Pay attention to the suitability of choosing ppe

1. To correctly select

To make good use of relays, correct selection of models is very important. First, we must have a thorough understanding of the nature, characteristics, and use requirements of the controlled objects and consider them carefully. The principles, applications, technical parameters, structural features, and specifications of selected relays must be mastered and analyzed. On this basis, the relay should be correctly selected according to the actual conditions and specific conditions of the project.

2. The understanding of the joint
When the relay coil is not energized, the static and dynamic contacts in the disconnected state are called “normally open contacts”; otherwise, they are called “normally closed contacts”. A moving contact is normally closed with one static contact and is normally open with another static contact, and they are called "changeover contacts". In the same relay, there can be one or more pairs of normally open contacts or normally closed contacts (both can also be present at the same time), and there can also be one set or array changeover contacts.

3. Elimination of contact sparks

Because the current of the relay contact is small, there will be no arc between the contacts, but there will be “spark discharge”. This is due to the presence of inductance in the contact circuit, and the overvoltage will appear on the inductor when it is disconnected. It is connected to the power supply voltage. They are added together on the contact gap, and the contact gap just separated by a certain distance is broken down and discharged. Due to the limited energy, only spark discharge will occur. The alternating capacitance between the capacitor and the energy in the inductor will make the spark discharge appear hidden and become a high-frequency signal, and the spark discharge joint will also cause damage. , And will reduce the service life, so we must try to eliminate, there are two kinds of practical anti-sparking circuit, as shown in Figure 1. 1. Its basic principle of action is to make the energy in the inductor pass through the rc without passing through the contact; 2. it is consumed on the load rl through the diode v when it is disconnected. Choose one of the applications. However, it should be noted that the rc parameter should be selected appropriately, and the parameter is mainly determined by experiments. Usually, the capacitor c can be selected according to the load current 1a/1 micro method. When using a diode, its positive and negative polarities should be connected correctly.

4. Increase the contact load method

In use, if the load capacity of the contact can not meet the requirements of the use, several pairs of contacts can be used to solve in parallel. However, adjustments should be made before use so that the synchronization of the contacts can meet the requirements. Otherwise, it will be counterproductive. The best method is to use intermediate relays or contactors to increase the load capacity of the contacts.

5. When the return coefficient is not satisfactory

The so-called return coefficient kf is a parameter that reflects the degree of cooperation between the suction force characteristics and the reaction force characteristics, that is, the difference between the relay action value and the release value. Relays of different uses often require different return coefficients. When the return coefficient of the relay cannot meet the requirements for use, the circuit shown in Figure 2 can be used to improve the return coefficient. Figure 2a is a circuit that reduces kf, while Figure 2b is a circuit that increases kf. The value of r in Fig. 2 should be appropriate, that is to say that the voltage applied to the relay coil must still be greater than the operating voltage (Fig. 2a) or the holding voltage (Fig. 2b) after the series r.

6. Pull release time does not meet the required improvement

When the relay's pull-in and release time can not meet the use requirements, the time constant of the relay coil loop can be changed to solve it. We know that the time constant t of the relay coil is equal to the ratio of the coil inductance l to the resistance r. If a resistor rf is series-connected in the relay coil loop, t2 (t2=l/r+rf) is smaller than t1 (t1=l/r).

When it is necessary to accelerate the pull-in, a resistance rf is connected in series in the coil circuit of the relay, and the power supply voltage is appropriately increased to ensure that the pull-in current of the coil remains unchanged, and the purpose of acceleration and pull-in can be achieved. If a capacitor c is connected in parallel across r, the pull-in time is shorter as shown in Figure 3a.

A diode is connected in parallel across the relay coil to achieve the purpose of delayed pull-in, see Figure 3b. Its principle is that after the relay coil is de-energized, it is equal to adding a short-circuit coil to the iron core, so that the release time is extended.

7. Correct selection of the relay's alarm action status

In general, alarms and interlocking instruments, dcs, and frequency converters are indispensable for the use of relays, that is, alarms and interlocks are mostly connected through relay contacts and alarms and interlocking circuits. When the alarm is to make the relay coil "charged" or in the "de-energized" state? We start from the reliability to analyze the "charged" and "lost power" state of the advantages and disadvantages.

The relay coil is "live" and operates to make the circuit alarm. This is the most easily understood design, but there is a hidden danger, that is, when the relevant wiring is not connected and an open circuit occurs, or if the relay coil power supply has a problem, the accident needs to occur. When the alarm occurs, the relay coil should be "live" but it will fail because of the above reasons. This result is very serious.

If the alarm is changed to “de-energized”, the meter wire will not be connected or open, the relay coil power supply problem, or the instrument failure. The reason is that when there is no alarm, the relay coil is in the "live" state. Once the above abnormal phenomenon occurs, the relay coil will return to the state of "de-energized". The operator and maintenance personnel will find out the cause of the alarm because of "alarm". , When the signal is found to be normal and alarm, it will go to find other reasons, and eliminate the fault, so that the alarm circuit back to normal, so as to avoid the occurrence of the phenomenon of missing, obviously "lost power" alarm is more reliable than "live" alarm.

Commercial Escalator

Economic Escalator,Safe Escalator,Commercial Escalator

Delfar Elevator Co., Ltd. , http://www.zjescalators.com

In the current market, the connection between the dome camera core and the casing is mostly a quick-release fastener structure. Since the cameras are generally installed on the non-vibrating building and the fixed frame, the failure of the core drop is less frequent, but individual Products still have hidden dangers in this area. Therefore, it needs to be improved so as to make the product more perfect.

Fault phenomenon

In the television monitoring of large-scale modern freight terminals, it is necessary to install a dome camera at the front end of a large crane boom such as a quayside container crane and a powder handling crane. In practical applications, the installed high-speed dome cameras have been damaged in large numbers in only half a year. The monitoring system has a high failure rate and is expensive to maintain.

Failure Analysis

Through the inspection of the fast dome camera, common fault phenomena and direct causes of damage are summarized in Table 1 below.

From the above table, it can be found that the direct cause of the above-mentioned damage of the dome camera is that the design of the mechanical structure of the connection between the dome and the shell of the dome is irrational. In use, failure occurs, the core falls off, and the electrical connection is disconnected. The ball failed.

Site use environment survey According to the field survey, the quayside crane is a large-scale steel frame structure with a suspended boom. When the crane is in operation, there is a large vibration movement at the front end of the boom that installs the dome camera. Taking a quayside container crane as an example, the main destructive vibrations are:

When a container crane on the shore lifts a container, more than 30 meters long, the position of the fast ball installed at the front end of the boom will continue to produce low-frequency vertical vibrations up to 3-5 centimeters;

When the container crane moves horizontally along the quay track, the front end of the boom will continue to generate lower-frequency horizontal vibrations with an amplitude of about 10 centimeters. In this case, the personnel need to support the fixed object to stand still;

Every time the container crane is put into and out of work or horizontally along the entire coast, in order to avoid the large masts and superstructures of large freighters, the front crane must be lifted up or down before the big boom, which will generate large shock vibrations.

When the crane moves forwards and backwards along the rails, no small vibration is generated, and it is transmitted to the fastball installed at the front end of the boom.

Therefore, fast dome cameras installed at the front end of long jibs of large quay cranes are constantly subject to horizontal and vertical low-frequency and large-amplitude vibration hazards and strong impact hazards, resulting in frequent damage to dome cameras. Conventional dome cameras are difficult to adapt to such a harsh vibration environment, and it takes too much time to damage. In fact, even if some dome cameras are installed in a fixed environment, occasionally there is a problem of poor core connection and poor electrical connection.

Failure Analysis of Failure Components

The dome camera weighs 1.2 kilograms and is mounted on the core mounting plate in the camera housing through a quick-release fastener structure. The connector is used between the core mounting plate and the commercial housing of the core. For electrical connection, the specific structure of the buckle is shown in Figure 1. After inspection of the damaged fastball camera at the scene, it was found that the damaged component was the core mounting base plate and the upper core cover attached to it, both of which were broken and cut off.

The main body of the core mounting base plate is an engineering plastic component, and the design of the base of the buckle is still relatively firm. However, the core mounting baseplate is on the side of the green sign fastener, and is easily broken near the fixing point fixed with the stud of the fastball housing. Because the fixed point has a certain distance from the force axis of the hanging floor buckle, it is similar to the cantilever type; the square hole is opened in the middle of the bottom plate, and the cross section of the fracture zone is only 17mm, so the stress is concentrated here and the structure is weak. . The adverse impact of the vibration shock again causes the core mounting base plate to break, causing the camera core fastener to loosen and detach, the camera electrical connector to be loosely connected, and the camera to malfunction. Therefore, there is a structural weak point in the core mounting base plate, and in the vibration and shock environment, fatigue mechanical damage occurs and breaks or breaks.

For the same reason, the upper shell of the core is also made of engineering plastics, and the retaining ring on the outer side of the upper buckle of the shell is also relatively thin. When the equipment is installed and operated, the inner ring controls the upper core mounting base buckle and the upper core cap buckle. The actual connecting area between the retainer and the upper housing is very small, with only 5mm on both sides, which is also the weak point of the structure. Due to the adverse impact of vibration and shock, the root of the retainer is easily broken from the upper casing, and the buckle of the core mounting base plate loses the restriction of the retainer and slides outwards, resulting in the loosening of the buckle group connection, the falling of the core, and the malfunction of the camera. . Therefore, the retainer of the upper housing is also structurally weak, and is subjected to fatigue mechanical damage due to vibration and it breaks and breaks.

Is the fast-camera's buckle connection structure itself reliable? By selecting a good dome camera, the core is removed and installed directly on the core. At this time, the two buckles are normally connected as in actual use. During the experiment, the buckle group was rocked by a series of methods such as continuously moving up and down, left and right, and swinging to simulate the vibration and impact effects of the fast ball on the quay crane. As a result, it takes a long time for the buckle to accidentally disengage, but the buckle can be reconnected after reinstallation. This shows that the buckle structure of the dome ball joint has a defect in the province and cannot withstand strong vibration impact. For this reason, even if the dome camera is installed in a fixed environment, there is an occasional problem of poor core connection and poor electrical connection.

For the above-mentioned problem of structural weakness and structural defects, it can be inferred that the root cause of the problem lies in the defects in product design and manufacturing.

ways to improve

For the core mounting base plate, the structural strength of the weak point of the member is reinforced. Reinforce ribs are provided at the joint between the concave hole of the round screw and the plane of the bottom plate; the material thickness of the entire bottom plastic member is thickened to ensure the fastness of the member, thereby decomposing stress concentration points and avoiding fatigue failure of the member. It is also possible to replace the core mounting base plate with metal components to improve the structural fastness.

One of the functions of the original damaged core upper cover buckle outer retainer is to lock the buckle connection of the upper core mounting bottom plate. The retainer actually has a certain distance from the buckle connection point, the locking effect is not good, and the impact itself is not small. Therefore, the method of increasing the strength of the weak point by simply increasing the connection area between the retainer and the base body is not the best improvement method, and cannot fully solve the defect that the fast ball core installation buckle will be accidentally released. A more reasonable method is to improve the ball comprehensively. Core installation buckle structure.

According to the analysis of the structure of the fast-ball buckle of FIG. 1 , there is a certain gap between the right side of the buckle of the core mounting base plate and the left side of the core decorative plate. When the ball buckle retainer breaks or the ball base mounting plate breaks and breaks, the buckle of the ball core mounting base plate easily slides to the gap on the right side, so that the buckle set is accidentally disengaged, the core ball falls off, and the camera malfunctions. In addition, even if the member is not broken, the snap-on retainer of the upper core cover as a snap-connected locking device is far from the fastening point, and the locking effect is poor, and the buckle-slipping of the core mounting base plate cannot be completely and reliably restricted. To the right of the gap, so that the buckle group accidentally released, will also lead to the above-mentioned failure phenomenon. Secondly, the rigidity of the core mounting base plate and the buckle itself is not enough, and the clearance of the structural fit is too large and the like may also cause accidental disengagement of the core mounting buckle group. Therefore, there are many factors that cause accidental disengagement of the dome camera mounting fasteners.

According to the above-mentioned defects of the buckle connection, a new fast ball core quick-release type buckle structure is improved and designed. The specific structure is shown in the figure, and the structure of the buckle fastening and disassembly device is shown in the figure. The main structural changes of the new fast ball core quick-release fasteners include:

Removed the original core on the shell buckle retainer and core buckle decorative plate;

The design increase is made of metal and includes a buckle closure for the button receiving hole;

The ball buckle is designed to be a floating form. It can be rotated to achieve convenient dismantlement of the ball core, and can also float left and right, cling to the right side, and increase the width of the buckle.

The new buckle baffle device is bent to the left, filling in the gap between the original buckle and the decorative plate. At the same time, the buckle of the core is always tight to the right side. Extruded by both sides, the buckles of the core buckles can be inserted into the snap holes of the core installation base plate smoothly and reliably, and the fasteners of the core mounting base plate will not slide to the right side. problem. In addition, the width of the ball buckle fastener is increased, and the button extends into the buckle baffle receiving hole to ensure that the two buckle faces of the buckle are completely in contact with the front face. When working, the forces are coaxial with each other and perpendicular to the fastening surface and cannot accidentally knock off the buckle. In this way, the new buckle baffle and the floating form core buckle actually constitute a reliable locking safety device, even in the shock and vibration environment, the fast ball camera buckle set will not accidentally disengage the failure, thus, completely Eliminate the hidden dangers of fastball cameras.

If the vibration of the actual use of the environment is very large, if necessary, you can use the safety screw to fasten the dome camera directly on the chassis. At the same time, the internal structure of the core should also meet the anti-vibration requirements.

For fast dome camera monitoring cameras that are to be used in vibrating environments, mechanical vibration reduction and vibration isolation devices may also be added to protect the equipment in an all-round way. The built-in mechanical vibration-reducing and vibration-isolation device in the camera is especially effective in improving the image shake and will be better than the software-based image stabilization.

The connection between the dome and the casing of the existing dome camera adopts a quick-release fastener structure. Since the cameras are generally installed on the non-vibrating building and the fixed frame, the failure of the core is less likely to occur, but individual products There is still such a hidden danger. Therefore, there is a need to improve structural design and strictly control materials and production processes. For the imitation products, we should fully grasp the product's structural principles, and take into account the gap between our material properties and production processes, and we should correct and improve the design. At the same time, we will carry out the necessary vibration fatigue test and quality test of impact test on the fastball products to detect hidden defects in time. Safety ropes must be installed during installation and maintenance of the dome to prevent accidents.

Chemical Mechanical Seal

Mechanical Seal,Pump Seal,Oil Seal

Longshen Seal Manufacture (Wuhan) Co., Ltd , http://www.topstarseal.com

The access control system should have a high degree of stability, choose an open hardware platform, support multiple communication methods, lay a solid foundation for interconnection and system integration between devices, and also have standardized and modular components to ensure great Flexibility and scalability.

Access control intercom system lightning protection

The outdoor door of the building is more likely to be struck by lightning, causing great inconvenience to the user and also causing great economic losses. Through the investigation and analysis of the causes of these lightning strikes, the main components of the crash are the power box, circuit board, and talker.

First, the main route to lightning strikes

(1) Directly hit mine. Direct lightning strikes the lightning directly on the object. The thundercloud near the ground induces an opposite charge on the protrusion. When the electric field strength between the thundercloud and the ground protrusion reaches the air breakdown strength, it will strike. Wear discharge, this type of thundercloud directly puncture discharge on the ground protrusion is called direct lightning. High buildings and their sides are subject to direct lightning strikes, and direct lightning strikes on the side of a building can be called side impact mines.

(2) Induction of thunder. Lightning strikes a conductor, such as a metal object next to the device, and indirectly strikes the object. Lightning induction is divided into electrostatic induction and electromagnetic induction. The formation of electrostatic induction is due to the induction of a large number of opposite charges on the top of ground projections when the cloud approaches the ground. When the thundercloud and other thunderclouds or other objects are discharged, the accumulated charge on the top of the protrusion suddenly loses its bondage, showing a high voltage and rapidly propagating in the form of lightning waves. The formation of electromagnetic induction is due to direct lightning currents that produce a rapidly changing strong magnetic field in the surrounding space, which induces high voltages in nearby metals. Induction mines are not as violent as thunder but they are much more likely to occur than direct thunder. Because direct lightning strikes only when lightning strikes the ground, it will cause disasters to the ground. Induction lightning, however, strikes lightning regardless of the lightning strikes on the ground, or lightning strikes between thunderclouds may occur and cause disasters. A lightning stroke can occur in a relatively large range and multiple small parts at the same time, and this induced high voltage can be transmitted far through the signal wires, power lines, telephone lines and other metal wires, resulting in lightning The scope has expanded.

Second, access control intercom system lightning installation

The following measures should be taken to prevent the above major lightning strikes:

1. The installation position of the power box should be properly selected.

(1) Avoid installing on the side wall of the house, especially on the side wall of the projected house, so as to prevent direct lightning strikes.

(2) Avoid installation on the side of a pipe where there is a metal pipe, a gas pipe, etc. Especially, the same side wall that is less than 5 meters from the metal pipe and the air pipe can not be installed.

2. Both the power box and the circuit board should be grounded. The grounding wire should be solid and reliable, and the grounding resistance should be ≤ 0.1Ω.

3, wiring should be correct and reasonable. Power lines and signal lines should be placed indoors to avoid outdoor wiring as much as possible, avoiding the same direction and cross wiring as metal pipes, air pipes, etc., and it is impossible to avoid wiring in the same direction as metal pipes, gas pipes, etc. The distance between the two should be ≥ 5 meters. . The wiring should be laid in a straight line to minimize bending wiring.

4. The power source of the power box should be connected to the power socket. When weather is prevented or weather changes may cause lightning, it is convenient to cut off the power in time to prevent lightning strikes.

Access control intercom purchase eight points one, strong stability

"Stable" is the first choice for the selection of access control systems. It should consider the mature products that are in the leading position in the world as far as possible, pass a number of authoritative certifications, and have many typical users. It has been operating for many years and has been highly recognized in the industry.

In terms of hardware, devices from the controller to the terminal are mature and stable products. As the core of the system, the access controller needs to support the offline mode of operation. It must use flash and other non-volatile memory chips, and the power loss or impact information will not be lost. Failure of the server and terminal to identify equipment does not affect the normal operation of the system. As the management software supported by the system, it should have a stable and reasonable database structure design. Between the hardware and the real-time polling method, the communication connection and address of the hardware should be maintained and monitored. Complete data integrity, reliability, consistency.

Second, extremely strong anti-destructive ability

Access control systems are used to protect people and property, so the system itself must be safe. The high security mentioned here refers to the natural or quasi-natural properties of the product or system. It should ensure the safety of the equipment and system operation and the safety of the operator. For example, the equipment and the system must be able to withstand high temperatures and low temperatures. Hot and humid, and can prevent static electricity, anti-jamming, etc.; on the other hand, access control and security systems should also have anti-human damage features, such as: with tamper alarm.

Third, excellent compatibility

To facilitate future upgrades, capacity expansion, and anti-jamming considerations, it is recommended that terminal identification devices comply with international standards be selected, and that the wider and better the compatibility, the better. Some formats have some advantages in terms of locality, but they do not conform to international standards. They will cause problems for future upgrades, capacity expansion, and anti-jamming. They should adhere to the principle of “practicality, stability, and compliance with standards”.

Fourth, flexible scalability and economy

It is suggested that the number of registered card rights need to reach 30,000, which can be suitable for the vast majority of customers on the storage capacity requirements, facilitate the attendance statistics and business scale expansion. The main equipments should adopt modular design and adopt advanced wiring methods. Through software and hardware upgrades, future system expansions can be achieved without having to make major changes to the system, maximizing the economical principle, and at the same time, products should be غير مجاز مي باشدt-effective.

Fifth, powerful software management functions

With the increasingly wide range of applications for access control systems, it is required to implement linkage control functions with other systems such as attendance management, security alarm, parking lot control, elevator control, consumption management, CCTV linkage, and online patrol. Therefore, the system software should have video Interfaces and support for extended functionality.

Six, easy to maintain
The system should be easy to install and configure, simple and popular, and have a unified network management capabilities, easy to maintain.

VII. Purchase of mature brand products at designated agents
A mature brand can guarantee a perfect and powerful service system. This includes two aspects: First, technical support and thoughtful after-sales service for the project; second, reliable follow-up research and development capabilities to ensure continuity and compatibility of new and old products.

Buying from agents can have reliable quality and perfect services. Buying from other channels may have lower prices, but technical support and after-sales service may not be enough.

Eight, product appearance

With the improvement of people's aesthetic standards, while pursuing function and practicality, one can use its design as one of the reference standards in order to realize additional functions of visual enjoyment.

Custom Design Slewing Bearing

Inner Gear Ring,Thrust Roller Bearing,Slewing Bearing For Crane

Slewing Bearing Co.,Ltd.  , http://www.slewingring-bearings.com

                    Product Description

1.Suitable for all kinds of plastic raw materials and color powder or granules
2.Fully stainless steel or iron contacting parts, rust free and easy to clean Installed with power control device to ensure safety.
3.Customizable for drying type model.

WITH HEATING

Recycling Line

Pet Bottle Recycling Line,Ldpe Film Washing Line,Bottle Recycling Machine

Lanhang Machinery Co., Ltd. , http://www.rh-plasticgranulator.com

Tiger Skull - Overview

Ancient name: Tripterygium "Compendium of Compendium of Materia Medica". Tigers

Tigers

Alias: Big cat licking.

Botanical name: bar plate return.

Growth environment: This product is a loose or relief-like vegetation. Born on the edge of the village, hillside, river, stream, and bushes, *** is more hiy.

Distribution: There are distributions in all parts of Guangdong and southern provinces in China.

Medication part: whole grass.

Collection period: summer and autumn.

Location: Hill.

Taste: cool, sour.

Function: heat.

Standard Padlock

Pad lock,Aluminium Alloy Lock,with Vane Keys

Hi-Stay Trading Co., Ltd. , http://www.szprotection.com

In recent years, video conferencing has become the first choice for business conferences due to its great advantages in network communications, and it has rapidly become popular among enterprises. Not only that, videoconferencing is rapidly merging with popular applications such as 3G, Internet of Things, and cloud computing, and its applications have become more extensive and deeper.

Video conferencing opens up a wider range of applications in the future
With the continuous development of technology, software video conferencing has broken through bottlenecks such as network bandwidth, interconnectivity, and stability, and quickly replaced hardware videoconferencing in a more stable, flexible, fast, and convenient manner, becoming the mainstream application in the industry. It is software video conferencing that has the advantages of easy deployment, easy maintenance, and high غير مجاز مي باشدt performance. This has led many SMEs to deploy video conferencing, which greatly expands the scope of video conferencing applications.

What is even more gratifying is that under the impetus of leading video conferencing manufacturers, high-definition, hi-fidelity, and removable software video conferencing have become a reality. The first full HD video conferencing system in China, Seegle Video Conference 2010 is For example, by adopting the concept of cloud computing and using the latest H.264 video codec technology, full-HD images with a resolution of 1080×1920 can be achieved. With excellent fault tolerance and transmission capabilities, higher quality at lower bandwidths can be achieved. Picture transmission, so that high-definition video conferencing is no longer a bandwidth killer.

In addition, the system can achieve audio and video effects that are indistinguishable from real soundtracks and steadily improve the effects of the conference. The system supports 3G networks, and can be quickly connected to conferences in many ways such as laptops and mobile phones, enabling many ordinary enterprises to enjoy high-definition video. Video conferencing brings the best conferencing experience.

With the help of software video conference systems such as Seegle Video Conference 2010, the application scope of video conferencing is no longer confined to the conference rooms of government agencies and large enterprises, but will be fully deployed in IT, power, and operators. In the fields of finance, transportation, education, and medical care, 40 million SMEs in China can also enjoy the efficiency gains of deploying videoconferencing.

Deeper application depth

With the development of videoconferencing so far, user needs are constantly changing. Videoconferencing is no longer just an exclusive tool for conferences, but it is becoming an integrated information system integrating collaboration, office, management, and storage, and is gradually becoming an enterprise informatization. The core part of communication will be implemented in all aspects of social activities, such as remote management, office collaboration, bidding, business negotiation, interview recruitment, education and training.

The in-depth application also puts a great test on videoconferencing vendors, requiring that they must have an accurate understanding of the user during the product requirements analysis phase, and must be able to achieve these requirements in the subsequent development process. In this regard, the Seegle videoconferencing system 2010 performed particularly well. From the early stage, it accurately grasped the needs of users, and assembled the strongest R&D team in the industry. All designs were based on the user's point of view. All designs were rigorously tested to ensure the products. Advanced, easy to use, and operability. The system supports only video display modes that can be set up, can support 10,000-person large-scale conferences, integrates the most advanced electronic whiteboard functions in the industry, and includes many conference support functions such as fully optimized file sharing, conference voting, etc. It can also meet the special needs of many special industries such as education, medical care, energy, aerospace, building materials, transportation and so on.

In the future, the application of videoconferencing will spread to all walks of life in society and infiltrate all places that need to be communicated. It will eventually become the word of informatization communication.

With the rapid development of society and economy and the improvement of informationization, the information age of educational facilities construction has also come. With the improvement of modern network technologies and the diversified development of education models, distance education has rapidly emerged as an education model that makes full use of network technology and has become one of the most important educational models.

The promotion of modern education and the rise of distance education are inevitable

Curing the current imbalance in the distribution of educational resources, distance education is the main force of science and technology is the social development and progress, and the essence of science and technology is the education. However, the current level of education in our country is not optimistic. Due to the vast territory and large population in China, the education level has obvious local limitations. For some remote areas, because of the occlusion of the environment, information exchange is not timely, and the level of education is quite backward. Therefore, the communication learning that overcomes the obstacles in the space area becomes the best choice.

The traditional measures of the aid education model usually take measures to organize teachers to go out for lectures or advanced teachers to carry out regular education, but this cannot solve the problem fundamentally. Organize teachers to go out to study, and then teach the students to perform the second conversion. Due to the subjective nature of the individual, it has been compromised to a certain extent. Regular support is also a drop-in, which does not enhance the comprehensive education concept. Through remote classrooms, students can go beyond the space constraints and bring students from different regions together in a classroom. Students can receive direct education, conduct classroom exchanges, and achieve real educational communication.

Increased social competition, distance education is the first choice for “charging”

With the rapid development of society and the acceleration of the pace of life, “living to the old to learn old” is no longer a self-disciplined spiritual realm, but a capital that is based on society. In order to be invincible in the fierce social competition, "charging" has become part of the lives of many incumbents.

For the office workers who work first and their time is tight, the traditional school education model is obviously not suitable. This is also the important reason for the rapid popularity of online classrooms in adult education. By accepting online education, people can arbitrarily choose the learning courses they need without considering space constraints. Based on the recording and broadcasting capabilities of remote video conferences, they can also reproduce the missed courses and effectively solve the time constraints. It saves time and effort, is flexible and free, and it caters to the ever-accelerating pace of life.

The prestigious school effect is increasing day by day and distance education effectively reduces stress

Decompression increases the pressure of competition in society. Preventing children from losing on the starting line has become the creed of choice for many parents. In order to squeeze into the threshold of elite schools, education spending has become the main economic burden for many families. According to relevant surveys, children’s education expenditure has already topped household’s daily expenses. The ever-increasing expenditure on education has made the emerging online classrooms quickly gaining attention.

Through online classes, students can not only effectively solve school choice problems, save education expenditure, but also help students develop their self-study ability. With the advent of information society, learning society and the era of knowledge economy, education is undergoing profound changes. Learning to learn by students has become a recognized goal in education. The model of separating students from teachers used in distance education will provide students with enough space for self-learning and fully explore their potential for self-study.

Solenoid Coil 15 to 15.9mm

Bomag Solenoid Coil,Electric Motor Coil,Solenoid Inductor Coil,Dirt Bike Ignition Coil

Brando Hardware Co., Ltd. , http://www.nbbrandohydraulic.com

Product Name Specification Material Steel/Origin Price (Yuan/Ton) Than Yesterday Last Week, General Line Φ6.5/8mm Q235 Handan Steel 4900 0 -50 450 High Line Φ6.5/8mm Q235 Handan Steel 5000 20 0 500 High Line Φ6.5/8mm Q235 New Gold 5000 20 50 500 High Line Φ6.5mm Q235 Licheng Taihang 4950 0 10 430 Rebar Φ12mm HRB335 Handan Steel 5130 0 -20 430 Rebar Φ12mm HRB335 Emerging Cast Pipe 5130 0 -20 430 Rebar Φ16-25mm HRB335 Handan 4900 0 -50 350 Rebar Φ16-25mm HRB335 Emerging Cast Pipe 4900 -30 -100 350 Rebar Φ16-28mm HRB335 Licheng Taihang 5100 0 50 430 Plate Screw Φ10mm HRB400 Licheng Taihang 4850 0 0 170 Hot rolled coil 1.8*1250*C Q235 Handan Steel 5820 10 -40 400 Hot rolled coil 2.0*1500*C Q235 Handan Steel 5700 30 -20 500 Hot rolled coil 2.5*1500*C Q235 Handan Steel 5400 - 70 - 120 460 Hot rolled coil 2.75*1500*C Q235 Handan Steel 5400 20 -30 540 Hot rolled coil 3.0*1500*C Q235 Handan Steel 5250 0 -100 470 Hot rolled coil 4.0-4.75*1500*C Q235 Handan Steel 5250 0 -100 570 Hot rolled coil 5.0-6.0*1500*C Q235 Handan Steel 5250 0 -100 570 Hot rolled coil 7.2-9.8*1500*C Q235 Handan Steel 5280 0 -100 600 Hot rolled coil 4.5 -10.0*1500*C Q235 Tiantie 523 0 -20 -120 580 Puzhong Plate 8.0mm Q235 Sky Steel, Handan Iron and Steel 6320 0 -180 730 Puzhong Plate 10.0mm Q235 Sky Steel, Handan Steel 6120 0 -180 740 Puzhong Plate 12.0mm Q235 Handan Steel 5890 0 -110 700 Puzhong board 14-25mm Q235 Handan steel 5830 0 -120 750 Puzhong board 14-25mm Q235 Wenfeng 5770 0 -130 770 Puzhong board 14-25mm Q235 Puyang 5800 0 -120 750 Puzhong board 14-25mm Q235 Yuanbaoshan 5760 0 -120 810 Low Alloy Plate 8mm Q345 Handan Steel 6470 0 -30 760 Angle Steel 50*5/6m Q235 An Steel 5300 0 100 600 Angle Steel 63*6 Q235 Ansteel 5300 0 100 650 Angle Steel 9# Q235 Ansteel 5300 0 100 650 Channel 8# Q235 Ansteel 5250 0 0 550 Channel 12# Q235 Handan Steel 5150 0 50 600 Channel Steel 20#/8m Q235 Jiangtian 5350 0 100 700 I-beam 12# Q235 Haicheng 5200 0 0 800 Steel 25b# Q235 Laiwu Steel 5400 0 50 700 I-beam 32# Q235 Laiwu Steel 5400 0 50 700 Hot-rolled strip 3.5mm and above *735*C Q235 Vertical and horizontal 4980 0 -20 480 Hot-rolled strip 5.5mm*685* C Q235 Vertical and horizontal 4980 0 -20 480 Hot-rolled strip 3.0mm*(685-735)*C Q195 Vertical and horizontal 5030 0 -20 500 Hot-rolled strip 3.5mm*(480-570)*C Q195 Wenfeng 5030 0 - 20 530 hot-rolled strip 3.75mm*520*C Q235 Wenfeng 4980 0 -20 480 hot-rolled strip 3.0mm * (480-570) * C Q235, Feng 49800-20450

Glow Plug

U & C Auto Parts Co., Ltd. , http://www.njradiator.com

I often see questions from users on some parking system forums and industry websites, saying that the parking system does not monitor images when it is operating. That is, the monitoring window is displayed as a fixed image, like a card screen. In fact, this is one of the common faults in the parking management system, which will cause some troubles in the management of the parking lot.

So how do you do when there is no monitoring image when the parking system is operating? There are two common reasons:

1. The software setting of the parking lot system is not appropriate. The general solution is to reset the relevant parameters of the video card in the “parking area setting” of the parking lot management system interface. For example, the correct selection of the video card model, in the parameter options of the lane, the image contrast in this item "Whether to monitor" must be selected;

2. The driver of the video capture card in the parking lot system is not installed correctly or not installed. The general solution is to right click on "My Computer", select "Device Manager", and then check if the driver of the video capture card is installed (if there is no installation or installation error, there will be corresponding prompts, such as a yellow question mark ) If it is not installed, then you can go to the manufacturer's website to download the driver for the corresponding product! If it still does not work, then you may suspect that the video capture card is broken. At this time, it is recommended that you send it to a professional for testing and replace it. !

Others

Solenoid Directional Control Valve,Hydraulic Valve,Solenoid Valve

Raypoo Technology Co., Ltd. , http://www.szhydraulicvalves.com

The content of carbohydrates in lettuce is low, while the content of inorganic salts and vitamins is relatively abundant, especially with more niacin. Niacin is an activator of insulin, and people with diabetes often eat lettuce, which improves sugar metabolism. Lettuce also contains a certain amount of trace elements zinc and iron, especially the iron in lettuce is easily absorbed by the body, often eating fresh lettuce, can prevent iron deficiency anemia. The content of potassium in lettuce is abundant, which is 27 times that of sodium salt, which is beneficial to the regulation of salt balance in vivo. For high blood pressure, heart disease and other patients, it has the effect of promoting diuresis, lowering blood pressure, and preventing heart rhythm disorders. Lettuce also has the functions of increasing appetite, stimulating secretion of digestive juice, promoting gastrointestinal motility and the like.

96.4 g per 100 g water content, protein 0.6 g, fat 0.1 g, carbohydrate 1.9 g, crude fiber 0.4 g, calcium 7 mg, phosphorus 31 mg, iron 2 mg, carotene 0.02 mg, thiamine 0.03 mg, nucleus Flavamine 0.02 mg, niacin 0.5 mg.

The content of carbohydrates in lettuce is low, while the content of inorganic salts and vitamins is relatively abundant, especially with more niacin. Niacin is an activator of insulin, and people with diabetes often eat lettuce, which improves sugar metabolism. Lettuce also contains a certain amount of trace elements zinc and iron, especially the iron in lettuce is easily absorbed by the body, often eating fresh lettuce, can prevent iron deficiency anemia. The content of potassium in lettuce is abundant, which is 27 times that of sodium salt, which is beneficial to the regulation of salt balance in vivo. For high blood pressure, heart disease and other patients, it has the effect of promoting diuresis, lowering blood pressure, and preventing heart rhythm disorders. Lettuce also has the functions of increasing appetite, stimulating secretion of digestive juice, promoting gastrointestinal motility and the like. However, if too much or regular consumption of lettuce, because lettuce lettuce compound on the optic nerve stimulation, will occur drowsiness and drowsiness poisoning reaction, leading to night blindness or other eye diseases induced, it is not appropriate to eat. The night blindness and eye diseases caused by eating more lettuce only need to stop eating lettuce and it will be improved in a few days. There are many nutrients in lettuce, including protein, fat, sugar, ash, vitamin A, vitamin B1, vitamin B2, vitamin c, trace elements such as calcium, phosphorus, iron, potassium, magnesium, silicon, and dietary fiber. The development of bones, hair, and skin helps people grow. In recent years, studies have found that lettuce contains an aromatic hydroxylated lipid, which can decompose carcinogenic nitrosamines in foods and prevent the formation of cancer cells. It has a preventive effect on the digestive system of liver cancer and gastric cancer. It can relieve cancer patients' response to radiotherapy or chemotherapy.

Funeral products

Embalming Table,Hospital Equipment,Medical Equipment

Flower Medical Equipment Co., Ltd. , http://www.shmedicalequipment.com

Product Name Specification Material Steel/Origin Price (Yuan/Ton) Than yesterday's previous week High Line Φ6.5mm Q235 Xing Steel 5040 0 -10 560 High Line Φ8/10mm Q235 Haixin 5040 0 -10 560 High Line Φ6 .5mm Q235 Sunshine 5040 0 -10 560 High Line Φ6.5mm Q235 Nangang 5120 0 -30 620 High Line Φ6.5mm Q335 Sha Steel 5120 0 -30 520 High Line Φ8mm Q335 Sha Steel 5100 0 0 500 High Line Φ6.5mm Q335 Yong Steel 5100 0 0 500 High Line Φ8mm Q335 Yong Steel 5100 0 0 500 High Line Φ6.5/8mm Q335 Ma Steel 5100 0 0 480 Rebar Φ10mm HRB335 Sha Steel 5070 0 0 470 Rebar Φ12mm HRB335 Sha Steel 5020 0 0 450 Rebar Φ14mm HRB335 Sand Steel 5000 0 0 450 Rebar Φ16-25mm HRB335 Sand Steel 5000 0 0 450 Rebar Φ10mm HRB335 Yong Steel 5070 0 10 500 Rebar Φ12mm HRB335 Yong Steel 5020 0 0 480 Rebar Φ14mm HRB335 Yong Steel 5000 0 0 470 Rebar Φ16 -25mm HRB335 Yong Steel 4980 0 0 460 Rebar Φ16-25mm HRB335 Ma Steel 5000 0 0 450 Rebar Φ16-25mm HRB335 South Steel 4980 -20 -20 430 Rebar Φ16-25mm HRB335 2672 Plant 4880 -30 -60 430 Thread Steel Φ18-25mm HRB335 Jiangyin up to 4860 -30 -60 410 Rebar Φ16-25mm HRB335 Ann Yang Xinyang 4860 -30 -60 410 Rebar Φ16-25mm HRB335 Shaanxi Longgang 4860 -30 -60 410 Rebar Φ18-25mm HRB335 Haixin 4860 -60 -90 410 Rebar Φ18-25mm HRB335 Ma Changjiang 4880 0 -80 430 Grade III Rebar Φ18-25mm HRB400 Masteel/Yong Steel 5120 0 0 460 Grade III Rebar Φ16mm HRB400 Sha Steel 5130 0 -20 470 Grade III Rebar Φ18-25mm HRB400 Sha Steel 5130 0 -20 470 Grade III Rebar Φ18-25mm HRB400 Pinggang 4900 0 -100 320 Grade III rebar Φ18-25mm HRB400 Nanchang 4900 0 -100 320 Grade III rebar Φ18-25mm HRB400 Rizhao 4900 0 -110 320 Round bar Φ10mm Q235 Yonggang 5090 0 0 420 Round bar Φ12mm Q235 Yong Steel 5080 0 0 420 Round Steel Φ14mm Q235 Yong Steel 5070 0 0 420 Round Steel Φ16mm Q235 Yong Steel 5060 0 0 420 Round Steel Φ18-20mm Q235 Yong Steel 5050 0 0 420 Hot Roll 2.75mm*1500*C Q235 Handan Steel 5500 0 0 550 Hot rolled coil 5.5mm*1500*C Q235 Handan Steel 5280 0 -70 580 Hot rolled coil 9.3mm*1500*C Q235 Handan Steel 5280 0 -70 580 Hot rolled coil 11.5mm*1500*C Q235 Handan Steel 5280 0 -70 550 Hot rolled coil 3.0mm*1500*C Q235 Shagang 5450 0 -50 600 Hot rolled coil 5.5mm*1250*C Q235 Shagang 5250 0 -100 550 Hot rolled coil 9.5mm*1500* C Q235 Shagang 5250 0 -100 550 Hot rolled coil 11.5mm*1500*C Q235 Shagang 5250 0 -100 520 Hot rolled coil 4.5*1250*C Q235 Rizhao 5270 0 -80 620 Hot rolled coil 5.75*1500*C Q235 Rizhao 5270 0 -80 620 Hot rolled coil 2.75mm*1250*C Q235 Masteel 5500 0 -50 550 Hot rolled coil 4.75mm*1800*C Q235 Masteel 5500 0 -50 600 Hot rolled coil 5.5mm*1800*C Q235 Masteel 5500 0 -50 670 Hot rolled coil 2.75mm*1500*C Q235 Tangshan Steel 5500 0 0 550 Hot Roll 4.5mm*1500*C Q235 Tang Steel 5350 0 0 650 Hot Rolled Roll 11.5mm*1500*C Q235 Tangsteel 5350 0 0 650 Strip 3.0*700 Q235 Beidai 4850 0 0 100 Strip 4.0*500 Q235 Beitai 4800 0 0 100 Strip 5.75*720 Q235 Beitai 4750 0 0 100 Strip 7.7*720 Q235 Beitai 4750 0 0 100 Strip 9.5 *720 Q235 Beitai 4750 0 0 100 Strip 11.5*720 Q235 Beitai 4800 0 0 100 Cold rolled sheet 1.0mm*1250*2500 DC01 Wuhan Iron and Steel 6550 0 0 850 Cold rolled sheet 1.2mm*1250*2500 DC01 Wuhan Iron and Steel 6500 0 0 850 Cold Rolled plate 1.5mm*1250*2500 DC01 Wuhan Iron and Steel 6500 0 0 850 Cold rolled plate 2.0mm*1250*2500 DC01 Wuhan Iron and Steel 6500 0 0 850 Cold rolled coil 2.5mm*1250*2500 DC01 Wuhan Iron and Steel 6500 0 0 800 Cold rolled coil 1.0mm* 1250*2500 ST12 Masteel 6550 0 0 850 Cold rolled coil 1.5mm*125 0*2500 ST12 Masteel 6500 0 0 850 Cold rolled coil 1.0mm*1250*C ST12 Meigang 6500 0 0 820 Cold rolled coil 1.5mm*1250*C ST12 Meigang 6500 0 0 900 Cold rolled coil 1.0mm*1500* C ST12 Ma Steel 6500 0 0 820 Cold rolled coil 1.0mm*1500*C spcc Tang Steel 6400 0 0 800 Product Name Specification Material Steel/Origin Price (Yuan/Ton) Yesterday Last Week 6mm Q235B Xinyu 6400 0 100 850 Puzhong board 8mm Q235A Xinyu 6300 0 100 800 Puzhong board 10mm Q235A Xinyu 6200 0 50 750 Puzhong board 14-20mm Q235A Xinyu 5980 0 30 880 Puzhong board 6mm Q235B Nangang 6400 0 100 850 Puzhong Plate 8mm Q235A Nangang 6300 0 100 800 Puzhong Plate 10mm Q235A Nangang 6200 0 50 750 Puzhong Plate 12mm Q235A Nangang 6000 0 50 900 Puzhong Plate 14-20mm Q235B Nangang 5980 0 30 980 Puzhong Plate 10mm Q235A Horse Steel 6200 0 50 700 Puzhong Plate 14-20mm Q235A Ma Steel 6000 0 50 900 Puzhong Plate 25mm Q235A Ma Steel 5980 0 30 900 Low Alloy Plate 6mm Q345 Nangang 6300 0 0 150 Low Alloy Plate 8mm Q345 Nangang 6150 0 0 450 Low Alloy Plate 10mm Q345 Nangang 6000 0 0 520 Low Alloy Plate 14-20mm Q345 Nangang 6500 0 0 850 Low Alloy Plate 14-20mm Q345 Masteel 6100 0 0 900 Low Alloy Plate 14-20mm Q345 Feida 6000 0 0 850 Boiler Plate 8mm 20g Nan Steel 7050 0 250 800 Boiler Plate 10mm 20g Nan Steel 6900 0 200 780 Boiler Plate 12mm 20g Nan Steel 6580 0 200 780 Boiler Plate 14-20mm 20g Nan Steel 6550 0 200 780 Container Plate 8mm 16MnR Xinyu 7220 0 250 900 Container Plate 10mm 16MnR Xinyu 7120 0 250 930 Container Plate 12mm 16MnR Nansteel/Xinyu 6750 0 240 880 Container Plate 14-25mm 16MnR Nangang/Xinyu 6700 0 250 850 Seamless Pipe 25*2.5 20# Wuxi 7500 0 500 1050 Seamless pipe 38*3.5 20# Wuxi 6700 0 300 950 Seamless pipe 48*4 20# Wuxi 6650 0 300 900 Seamless pipe 57*3.5 20# Wuxi 6650 0 300 950 None Seam pipe 60*4 20# Wuxi 6650 0 300 950 I-beam 20#/b Q235 Laiwu Steel 5300 0 450 800 I-beam 36#/b Q235 Laiwu Steel 5400 0 420 650 Channel 16#a Q235 Masteel 5450 0 300 850 channel steel 25# Q235 Wugang 5600 0 350 950 50*50*5mm angle steel Q235/magang steel 5350 0 50 550 angle steel 50*50*5mm Q235 Shougang 5350 0 150 700 galvanized coil 0.5mm*1000*2000 JY Wuhan Iron and Steel 6950 0 350 950 Galvanized coil 0.7mm*1000*2000 JY Wuhan Steel 6750 0 250 950 Galvanized coil 1.0mm*1000*2000 JY Wuhan Iron and Steel 6550 0 150 900 Galvanized coil 0.5mm*1000*2000 ST02Z 695003501000 galvanized coil 0.75mm * 1000 * 2000 ST02Z BX 66800200980 galvanized coil 1.0mm * 1000 * 2000 ST02Z BX 65500150900

Window Lid Aluminum Jar

Window Lid Aluminum Jar,Aluminum Jar with Window Lid,Aluminum Jar with Window Cap

Honesty-Honored E-Commerce Firm , http://www.ywغير مجاز مي باشدmeticpacking.com