Applied Mechanics and Materials Vols. 321-324

Abstract: A wide variety of current embedded microcontrollers like 8,16 and 32-bit of Freescale Micro Control Unit(MCU) performance is stable and various. Mc9s12xs128 is a kind of Freescale 16-bit microcontroller. The concept of the Freescale Microcontroller Minimum System and the principle of realization is systematically elaborated. Many peripheral module such as Serial Communication, Liquid Crystal Display(LCD), keyboard scanning and Digital Tube Display are developed after a thorough understanding of the basic theory of Minimum System. In addition to this work, a very detailed description of each module's hardware design and software programming methodology is also made to show that an embedded system can achieve a specific function.

Abstract: Placement is the crucial step in modern VLSI physical design, and the result may decisively influence the follow-up wiring design. The advantages and limitations of the random optimization algorithm, ant colony algorithm, genetic algorithm, heuristic algorithm and simulated annealing algorithm which are used for placement optimization were analyzed in allusion to optimal search problems of VLSI placement. With a view to speedability of search, global convergence and the optimality of the solution, the initial placement is received through integrated use of all algorithms. In the meantime, the iterative improvement placement is realized by means of dynamic multi-branch tree. Practice has shown that the structure of the algorithm is clear, and it can also ensure the optimality of the received solution.

Abstract: GaN ultraviolet photoelectric detector have advantages of high quantum efficiency, work at room temperature, high-temperature resistance, good corrosion resistance, resistance to radiation ability etc. Therefore, research of GaN ultraviolet photoelectric detector has important application value in the spacecraft, fire monitoring, ultraviolet communication and other fields. MSM Schottky type ultraviolet photoelectric detector has been prepared by a metal organic chemical vapor phase epitaxial deposition method in growth of high quality GaN semiconductor film on the sapphire substrate. Then optical and electrical properties of device have been studied by analyzing its illumination and light response performance. The detector sample has high pressure resistance and response degree. After annealed treatment, the ultraviolet detector has response peak for 0.19 A/W and response time for 70ns.

Abstract: RFID belongs to the basic input device in the IOT(Internet of Things) applications. The country has attached much importance to the technique and application of IOT, and RFID has been widely used in logistics, warehousing, traffic, cattle raising and some other industries. The thesis employs MFRC531 chip and Atmel 89C518 bit microprocessors to design and realize a RFID card reader which can be characterized by simple circuits, easy to realize and convenient to debug. Thus, it may be referred by IOT technicians.

Abstract: In this paper, a high-speed data transmission system based on FPGA (Field Programmable Gate Array) and USB 2.0 (Universal Serial Bus) technology is designed. Firstly, we introduce the hardware of the data transmission system, which includes data acquisition circuit, transmission circuit and power conversion circuit, etc. Secondly, the corresponding software design including USB firmware program, USB driver and firmware modification are described in detail. Finally, the corresponding experiment has been carried out, which show that the developed system will help to achieve the data transmission system with the characteristics of high-speed, integration and low power consumption, etc.

Abstract: This paper presents the chip design strategy of resistance type humidity readout circuit for greenhouse application. The designed chip includes resistance change type humidity readout circuit, temperature compensation circuit, low voltage dropout generator (LDO), and analog to digital convertor (ADC).The humidity sensor which used in this research is HCZ_H8, and it is produced by Ghitron Company .Because resistance change type humidity sensor depends much on the temperature, so this paper develops a temperature sensing circuit to compensate the effects caused by the temperature change. The ADC in this research is13-bit fully-differential incremental delta sigma A/D converter, and the power supply is 3.3v, but the power supply of the humidity readout circuit is 5v, so a low voltage dropout generator (LDO) is included to match the power supply.

Abstract: So far, all known charge control algorithm have failed as they commonly falsely detect overcharge at random times in the charging and leave the battery partially charged. In traditional charging environments, the current is controlled to a desired value and the thresholds are calculated for this specific value. The goal of this paper is to propose adequate algorithms that would improve the battery charging. New solutions that address the specific problem for modular solar panels are developed in this paper.

Abstract: A new display technology is being developed that uses quantum dot materials, the luminescence with different color different dot sizes from CdSe quantum dot made by us is presented. The fabrication methods, the luminescence behaviors for the materials are also reviewed. A bright future of the applications of the quantum dots luminescence materials and its applications in display devices is described.

Abstract: This essay uses the method of photon tracing to describe the simulation of PbSe quantum dots luminescent solar concentrator based on GoldSim software and optimize its size. We find that under the condition of size optimization, the photoelectric conversion efficiency of silicon solar cells which stick to the side of PbSe quantum dots luminescent solar concentrator can reach 32.5%. It explains that PbSe quantum dots are very suitable for LSC system.

Abstract: The traditional wavelength filter only have one face of grating, the gratings length must be long enough to obtain good filtering result, so the filter device can not be made to a small size. We describe a procedure for rapidly and conveniently prototyping Bragg grating on the three side of the polymer ridge waveguide using holographic interferometry and micro-molding processes. In this experiment, the master of the periodic structure was created on an i-line submicrometer positive photoresist film by a holographic interference using a He-Cd (325nm) laser. A subsequent mold using polydimethylsiloxane (PDMS) polymer was cast against this master and used as a stamp to transfer the grating pattern onto a UV cure epoxy. The technique shows accurate control for the transferring of a gratings period and depth. It can obtain the filtering result with very short grating length which means that it can be made with a small filtering device.