Ten Daily Electronic Common Sense-Section 67

Vacuum sealing wax：

Vacuum sealing wax is made of waxy heavy lubricating oil fraction or mixture of bitumen and cylinder oil through oxidation and shallow refining, and it is in the form of dark black solid. Vacuum sealing wax is not easy to become brittle and dry when the temperature changes rapidly.

What kind of microcontroller is SJAl000?

SJAl000 is an I/O device based on memory addressing single chip microcomputer.

Which signals are directly driven by the Spartan-3E FPGA experiment board through Resistorss?

The Spartan-3E FPGA experiment board directly drives 5 VGA signals through resistors, among which VGA RED, VGA GREEN and VGA_BLUE are all controlled by lbit data.

What is the priority-based cache management strategy?

The cache resources carried by nodes in a delay-tolerant network are limited, so the cleaning strategy when the buffer space overflows and the priority of message forwarding often affect the performance of the routing algorithm. At the same time, the number of hops passed by the message and the time that it has survived are used as the comprehensive criteria for measuring the priority, so that the number of hops and messages that have survived for less time have higher priority, avoiding the chance of using only the number of hops as the metric.
Use C(M to represent the number of hops of message M, use 3(M to represent the time that message M has survived, TTL to represent the time the message can survive (ie, the life cycle of the message), and NC to represent the number of nodes in the network.
Use H(M) of Equation (3.8) and D(M) of Equation (3.9) to measure the influence of the number of hops and the elapsed time on the priority, respectively. Finally, use Equation (3.10) to calculate the message M The final priority of UP( pomelo. The more hops the message M passes through, the larger the value of its day (M), and the smaller the value of its final priority UP (the larvae. And the longer the message M has survived, Then the value of its r(M is larger, and the value of its final priority UP(M is also smaller.
In this way, considering the influence of the number of hops and the elapsed time, a message with a small number of hops and a message with a short elapsed time can initially have a relatively high priority. As time goes by, the priority of messages with fewer hops will decrease, and messages with more hops may also get higher priority. With the constant change of message priority, the forwarding times of each message in the cache is balanced to a certain extent, and some messages are prevented from being forwarded all the time.

What are the structures of LED digital tubes?

There are two structures, “common anode” and “common cathode”.

What is Java?

Java is a language similar to C and C, but with additions and deletions. In order to achieve its simplicity, safety and other characteristics.

What are the naming rules for identifiers?

• The naming rules are as follows:
  1. It must start with a letter;
  2. The underscore cannot be used together;
  3. The last character cannot be an underscore;
  4. It is not sensitive to uppercase and lowercase letters (English letters do not distinguish between uppercase and lowercase) );
  5. The length cannot exceed 32 characters.

How to write Testbench for testing?

The process of writing a Testbench for testing is as follows:
Generate an analog stimulus (waveform), add the generated stimulus to the tested module and observe its output response. Compare the output response to the expected value to judge the correctness of the design.

What pipeline conflicts can occur in 28x?

Conflicts arising from simultaneous read and write operations in the same data space; register conflicts.

How is the DP master configured with the intelligent slave master-slave communication?

The automation task can be divided into several sub-tasks controlled by multiple PLCs. These sub-tasks are processed independently and efficiently by several CPUs. These CPUs are used as DP master stations and intelligent slave stations in the DP network.  
The DP master station does not directly access the physical I/O area of the intelligent slave station, but exchanges data through the I/O area of the two communication parties specified during the configuration of the slave station. This I/O area cannot occupy the physical I/O address area allocated to the I/O module.  
The data exchange between the master station and the slave station is automatically completed by the PLC operating system periodically and does not require user programming, but the user must make the communication connection between the master station and the intelligent slave station and the address area for data exchange. configuration. This communication method is called master/slave (Master/Slave) communication mode, referred to as MS mode for short.