2011.10
About Instruments Today No. 184
Enhanced Forward and Backward THz-Wave Difference Frequency Generations from Two-Dimensional Nonlinear Waveguide [ 下載 PDF ]
Tsong-Dong Wang, Yen-Chieh Huang
We report enhanced forward and backward THz-wave difference frequency generations at 197 and 469 µm from a rectangular crystal rod made of periodically poled lithium niobate (PPLN) with an aperture of 0.5 × 0.6 mm2 and length of 25 mm. The crystal rod appears as a waveguide for the THz waves but as a bulk material for the optical mixing waves at 1.54 µm. We measure enhancement factors of 1.6 and 1.8 for the forward and backward THz output powers, respectively, from the crystal rod when compared with those from a PPLN crystal slab waveguide of the same length, thickness, and domain period at an equal intensity of 100 MW/cm2 for the pump and signal waves in the two crystals.
Fabrication of Micro Tandem Lens Array by Glass Molding Technique [ 下載 PDF ]
Chien-Yao Huang, Hsiao-Yu Chou, Keng-Souo Chang, Wen-Tse Hsiao, Chang-Pin Chou
In recent years, micro lens array (MLA) has become an important element for optical systems. One of the most important applications of MLA is to uniform the intensity of light. The alignment construction of double-sided MLA is easier than one-sided MLA. The MLA fabricated by glass materials could be used in high energy systems or high temperature environment, such as laser system. Glass based MLA could be fabricated by laser machining, photolithography and precision glass molding (PGM) technologies, but the former two technologies are not suitable for manufacturing. In this paper, we proposed a manufacturing method of double-sided MLA by laser machining and PGM technique. A micro holes array was fi rstly fabricated on the surface of silicon carbide (SiC) mold material with the diameter of 500 µm and depth of 200 µm. The double-sided MLA was then molded by PGM process with two molds. In this paper, the parameters including laser pulse repetition rate, laser scanning speed, molding temperature and molding force, and the characteristics of double-sided MLA such as profi le and refractive index were discussed. We obtained the result that the double-sided MLA with the diameter of 20 mm and each lens with the height of 52 µm, the radius of 851 µm, and the pitch of 700 µm on soda lime glass.
Applications of Information Technology in Nuclear Radioactive Monitoring and Low-Level Radioactive Waste Management [ 下載 PDF ]
I-Hsin Chou
The main goal of this article is to present practical applications of nuclear radioactive monitoring and low-level radioactive waste management using the information technology (IT). The reasons of nuclear energy needed in Taiwan's government energy policy and current status of nuclear power plants are explained in the introduction section. Next, the detailed descriptions of IT which include network technology, distributed database, data mining, extension markup language (XML), ontology web Language (OWL) as well as cloud computing are introduced. To demonstrate the practical applied applications, a real-time radiation monitoring system and an integrated radioactive waste management system are described. In addition, the fundamental design of web service for the general internet users: information exchange model (i.e., XML schema) and Taiwan Radioactive Waste Management Ontology (TRWMO) are presented. Finally, the summary and a service-oriented integrated architecture for the future development are provided.
Conceptual Design of an FPGA-Based Digital Instrumentation and Control System for Nuclear Power Plants [ 下載 PDF ]
Jun-Jen Lu, Hwai-Pwu Chou, Kin-Wah Wong
Due to the high density and reliability and low nonrecurring engineering (NRE) expense, the fi eld programmable gate array (FPGA) technology has been used extensively for commercial applications over the last decade. However, not until recently, there are only few applications in using FPGA technology for instrumentation and control (I&C) systems in nuclear power plants (NPP). A diverse backup implementation for the digital I&C systems is an important means to defense against the undetectable software faults and the common cause failures. In this study, the application of quad-redundant FPGA technology in RPS design for the NPP will be presented.
Laser Scan Pico-Projector with MEMS Scanning Mirror [ 下載 PDF ]
Andrew Hung, Ryan Kao
In this article, we introduce the three primary pico-projector technologies and focus on discussing the working principle and features of laser scan projection display with MEMS scanning mirror. The MEMS scanning mirror scans RGB laser beams aligned into a single spot into a two-dimensional image area to form an image. Each pixel color is formed by modulating the RGB lasers simultaneously that leads to high optical efficiency, lower power consumption, wide color gamut and focus free operation. The geometrical distortion and brightness uniformity due to laser incident angle and sinusoidal motion of the scanning mirror may be compensated and corrected through fi rmware computation without additional optical components. Therefore, the light engine requires the least components and is inherently small and low cost, and is best suited for embedded projection application.
The Development of Data Acquisition Speed in Ellipsometry [ 下載 PDF ]
Yu-Faye Chao, Meng-Wei Wang, Chun-I Chuang, Chien-Yuan Han
Utilizing the polarization changes by refl ection, ellipsometry can extract the physical properties of a medium. For measuring the dynamic changes when a material is under heating, etching, deposition, exposure to light, etc. The measuring speed becomes one of the major targets for developing in ellipsometry. This laboratory started to measure a static thin fi lm by measuring three intensities at specifi c positions of analyzer through a simple PSA confi guration. Later, we employed the photo- elastic modulator to substitute the quarter wave plate in a PCSA confi guration for establishing the real time/in situ monitoring the etching process in a plasma etching chamber. In stead of using lock-in amplifi er, we installed a DAQ system in our own laboratory. By post fl ight analysis technique, we are able to measure the ellipsometric parameters in 20 µs.
"OLED—A Physiologically, Psychologically and Environmentally-Friendly Light Source Ever in Human History" [ 下載 PDF ]
Jwo-Huei Jou, Yung-Cheng Jou, Shiang-Hau Peng
Incandescent bulbs and fl uorescent tubes provide fundamental lighting needs but barely satisfy our desire for natural lighting, as from the sun, with time-varying color temperature. To have sunlight-style illumination, emission with daylight chromaticity and a wide color-temperature (CT) span is essential. However, no single lighting device, including previously published white organic light-emitting diodes (OLED) as well as the latest white light emitting diode (LED), exhibits daylight-like emission with a color temperature range covering that of sunlight. Here we demonstrate a man-made lighting device that is composed of a single simple OLED capable of yielding daylight chromaticity with color-temperature ranging from 2300 ± 70 to 7900 ± 1400 K, covering that of sunlight, i.e. 3250 K at dawn, 2500 K at dusk, and 5500 K at noon or 8000 K at noon in high-latitude country. Throughout this context, we will fi rst introduce some disruptive features of OLED, followed by an elucidation on the effect of CT on human health.
Application of Pt/In2O3-WO3 Material for Biomedical Nitric Oxide Gas Sensor [ 下載 PDF ]
Ren-Jang Wu, Pei-Yu Chang, Murthy Chavali, Ren-Guang Wu
This study was using impregnation method to fabricate bimetal oxides In2O3-WO3, the sensing materials were covered in a screen printing gold electrode on alumina substrate as a nitric oxide sensor. In the experiment by change the amount of In2O3 and WO3 to get various weight ratios and we change the amount of platinum doping and calcinations temperature to get the sensing material which has the best sensor response of nitric oxide sensing. The prepared samples were characterized by transmission electron microscope (TEM) techniques.
A Solar LED Module with the Guiding Function for Pedestrians [ 下載 PDF ]
Hsieh-Ping Chen
A glowing device with the guiding function for pedestrians is designed. On top of sidewalks or stairs, we embed lots of new guiding modules in order to become the newest guiding system. During daytime, the rechargeable batteries absorb sunlight and store it as energy. And during the night, these modules are formed as a straight row, and at the original state, the fi rst and last modules appear as a weak blue light. But when the pedestrians step onto either end of the module, the stepped module will glow bright LED blue light, meanwhile, send a wireless signal to the next module. And once the second module receives the signal, and it will also glow blue light, and then the second passes the signal to the third, the fourth, fi fth, and so on. The system will automatically shut off by itself when nobody is stepping on the modules, and then it returns to the original state, weak blue light. Since this system has cool LED light changes, it can interact with the pedestrians, and it'll intrigue people, and those people will like to follow these guiding modules. And if this system is to be brought to the sidewalks of streets on the zebra crossings, or be guided to cross-over bridges and underground passages, pedestrians won't cross streets carelessly. This device isn't just intriguing, it also brings safety to all people.
