Fabrication and temperature coefficient compensation technology of low cost high temperature pressure sensor

For the purposes of pressure measurement at high temperature in oil drilling industry as well as in other industrial measurement and control systems, the strain gauge chip of piezoresistive pressure sensor is designed based on separation by implanted oxygen (SIMOX) SOI (silicon on insulator) technology, and then fabricated in the micro-machining work bay. Some kinds of sensor mechanical structures are designed for different customers and conditions. The thermal coefficients of expansion (TCE) mismatches between different materials within the high-pressure sensor system are investigated. The sensor is fabricated successfully by using high temperature packaging process. The temperature coefficient of sensitivity (TCS) and temperature coefficient of offset (TCO) compensation circuitry is demonstrated. Based on experimental data, the sensor is tested with high accuracy and good stability.     

The low temperature polysilicon (LTPS) thin film MOS Schottky diode on glass substrate for low cost and high performance CO sensing applications

The Au/SnO₂/n-LTPS MOS Schottky diode prepared on a glass substrate for carbon monoxide (CO) sensing applications is studied. The n-LTPS (n-type low temperature polysilicon) is prepared by excimer laser annealing and PH₃ plasma treatment of an amorphous Si thin film on glass substrate. The developed Schottky diode exhibits a high relative response ratio of ∼546% to 100 ppm CO ambient under condition of 200 °C and −3 V bias. The response ratio is better than the reported SnO₂ based resistive type CO sensors of 100% and 37%, respectively on poly-alumina and glass substrates or comparable to 390% of Pt-AlGaN/GaN Schottky diode CO sensor. Thus, the Au/SnO₂/n-LTPS Schottky diode has the potential to develop a low cost high performance CO sensor.     

A high gain low noise amplifier for implantable cardio technologies

Microsystem Technologies - Increase in large number of neurological and cardiovascular illness that cannot be treated by medicine alone have brought about a critical development in the quantity of...     

Discounting decision for enterprises with high fixed cost and low variable cost

Higher sales are the key to increased profit, especially for low variable cost industries. The use of quantity discount to promote business is an important way to increase sales. This study evaluates the use of discount, prepaid, multiple‐purchase credit to increase sales. The purpose is to develop a strategy to maximize the unit revenue by simultaneously determining the discount rate and utility. A numerical example and sensitivity analysis are given to illustrate the theory.     

一种新型的低成本高性能在线式UPS

提出了一种新型的低成本单相在线不间断电源(UPS)。该系统包括具有功率因数校正(PFC)功能的整流/升压转换器和连接到DC-Link总线的两桥臂逆变器,电池组通过一个非常简单的系统可直接连接到DC-Link总线。采用6开关管的架构,相对于传统的8开关管全桥拓扑结构的系统降低了成本。即使在非线性负载下,该系统仍具有功率密度高和高品质输出电压的特点。最后详细描述了电路操作、分析以及模拟和实验结果。     

高电源抑制比低温漂带隙基准源设计

设计并实现了一种新的高PSRR、低TC带隙基准源。重点研究了带隙基准源电源抑制能力,尤其是高频PSRR,达到宽频带范围PSRR高性能指标。采用0.35μm BiCMOS工艺进行仿真,结果表明,PSRR在1 Hz频率下达-108.5 dB,在15 MHz频率下达-58.9 dB;采用二次温漂补偿电路使得带隙基准源常温下输出参考电压1.183 V,在-40℃⁹5℃温度范围内,温漂系数低达1.5 ppm/℃。     

可移动式燃气表高低温准确度检测装置的研制及推广

环境温度对燃气表的计量性能有何影响、影响多大,是一个值得探讨的问题。研制一套标准装置,检测燃气表在高低温环境下的计量性能,对实际生活和工业中的燃气计量有着非常重要的意义。     

低成本SINS/GPS组合导航系统方案

低成本捷联惯性导航系统SINS、GPS硬件和相应的组合导航算法已经开始成熟,但仍然缺少简单可行的、完整的组合系统方案.针对低成本SINS\GPS组合导航设计了一套完整的方案.首先利用GPRS和TCP/IP通信链路实时传输GPS差分数据,提高GPS定位精度.用计算机串口接收SINS\GPS数据,并利用计算机时间使SINS和GPS数据同步.然后给出了SINS速度和位置更新的简化算法,由于低成本SINS无法确定航向角,所以使用SINS自带的姿态和航向参考系统输出的航姿信息.最后阐述了方案采用的组合导航数据融合卡尔曼滤波模型,并以RTK定位数据为参考真值进行了车载实验,实验表明组合系统更加稳健,定位精度明显提高.     

A compact uniplanar ACS fed multi band low cost printed antenna for modern 2.4/3.5/5 GHz applications

Microsystem Technologies - A uniplanar compact triple operating band asymmetric coplanar strip (ACS) fed printed antenna loaded with multiple L-shaped branches and the asymmetric rectangular ground...     

In vivo monitoring of oxidative burst induced by ultraviolet A and C stress for oilseed rape by microbiosensor

In this paper, poly-o-phenylenediamine and Pt microparticle modified Pt electrode (POPD/Pt-MP/Pt) as microbiosensor has been developed to monitor in vivo oxidative burst induced by ultraviolet A (UV-A) and ultraviolet C (UV-C) radiation stress in oilseed rape (Brassica napus L.). Twice oxidative bursts were detected, appearing at 2 and 25 h, respectively. According to the peak area of amperometry, the amount of H₂O₂ induced by UV stress was estimated to be 6.2 × 10⁻¹⁰ and 3.1 × 10⁻¹⁰ mol for such two oxidative bursts in detected leafstalk, respectively. This novel microbiosensor provides an effective tool for studying the defense reaction of the plant in the situation of UV stress and probing the antioxidative mechanism of the antioxidative enzyme.     

The column protocol: A high availability and low message cost solution for managing replicated data

This paper presents a quorum-based replica control protocol which is resilient to network partitioning. In the best case, the protocol generates quorums of a constant size. When some replicas are inaccessible, the quorum size increases gradually and may be as large as O(n), where n is the number of replicas. However, the expected quorum size is shown to remain constant as n grows. This is a desirable property since the message cost for accessing replicated data is directly proportional to the quorum size. Moreover, the availability of the protocol is shown to be comparably high. With the two properties—constant expected quorum size and comparably high availability—the protocol is thus practical for managing replicated data.     

一种高性价比的PVFS并行文件系统

分析PVFS并行文件系统的构成,得出客户机软件、元数据服务器软件和数据服务器软件之间的接口关系,然后研究一种由PC客户机、PC元数据服务器和低价数据服务器共同构成的PVFS系统,其中客户及与元数据服务器不做重要改变,数据服务器软件需要开发修改以适应新的硬件平台,使得以更低的成本实现相同的系统或者以相同的硬件成本实现更高的性能。     

Examination of Au/SnO2 core-shell architecture nanoparticle for low temperature gas sensing applications

Au/SnO₂ core-shell structure nanoparticles (NPs) were synthesized using two methods, microwave and conventional precipitation. In both cases, the size of the Au core was 12-18 nm and the thickness of the SnO₂ shell was 8-12 nm. The particle size of SnO₂ synthesized using the microwave and precipitation method was 3-5 nm and 1-2 nm, respectively. Upon heating to 400-600 °C, both particles maintained their core-shell morphology but the smaller SnO₂ particles prepared using the precipitation method were more sintered. The resistance changes in films of these particles were measured as a function of CO concentration. The Au/SnO₂ particles prepared using the microwave method showed higher sensor response than those prepared using the precipitation method, even providing a significant signal at testing temperatures approaching ambient conditions, thereby affording a new class of material for gas sensing. Both sets of core-shell particles showed higher sensor response than the SnO₂ nanoparticles. The role of the Au core as a catalyst in improving the adsorption and oxidation of CO gas is important for improving the low temperature response. In addition, the maintenance of the size of SnO₂ in the microwave method during sintering contributed to the higher response towards CO sensing.     

On the behaviour of low cost laser scanners in HW/SW particle filter SLAM applications

Particle filters (PFs) are computationally intensive sequential Monte Carlo estimation methods with applications in the field of mobile robotics for performing tasks such as tracking, simultaneous localization and mapping (SLAM) and navigation, by dealing with the uncertainties and/or noise generated by the sensors as well as with the intrinsic uncertainties of the environment. However, the application of PFs with an important number of particles has traditionally been difficult to implement in real-time applications due to the huge number of operations they require. This work presents a hardware implementation on FPGA (field programmable gate arrays) of a PF applied to SLAM which aims to accelerate the execution time of the PF algorithm with moderate resource. The presented system is evaluated for different sensors including a low cost Neato XV-11 laser scanner sensor. First the system is validated by post processing data provided by a realistic simulation of a differential robot, equipped with a hacked Neato XV-11 laser scanner, that navigates in the Robot@Factory competition maze. The robot was simulated using SimTwo, which is a realistic simulation software that can support several types of robots. The simulator provides the robot ground truth, odometry and the laser scanner data. Then the proposed solution is further validated on standard laser scanner sensors in complex environments. The results achieved from this study confirmed the possible use of low cost laser scanner for different robotics applications which benefits in several aspects due to its cost and the increased speed provided by the SLAM algorithm running on FPGA.     

Design and performance investigation of a low profile MIMO/Diversity antenna for WLAN/WiMAX/HIPERLAN applications with high isolation

A low profile triband compact multiple input multiple output (MIMO) antenna operating at WLAN, WiMAX, and HIPERLAN bands is presented. The proposed MIMO antenna consists of two planar inverted‐F antenna elements located at the top two corners of printed circuit board (PCB). Dimensions of each antenna elements are reduced substantially by employing a meandered line and folded patch structure so that it occupies a small volume of 9 × 8.8 × 5.4 mm³. The proposed antenna consists of three arms namely, Main arm, Side arm 1, and Side arm 2. Each individual arm resonates corresponding to the λ/4 electrical length. Characterization of the antenna is carried out in the mobile environment as well as in user proximity. In the presence of mobile environment which includes liquid crystal display (LCD), Battery, RF components, and plastic housing, the isolation as well as reflection coefficient parameters deteriorated. To avoid the aggravation of S‐parameters, two nonradiating folded shorting strips are connected between each antenna element and ground plane of PCB. This folded shorting strip not only improves the isolation between ports but also prevent the deterioration of reflection coefficient parameter. The total efficiency, envelope correlation coefficient, and multiplexing efficiency are studied in the user proximity. The optimized structure is fabricated and measured. The measured S‐parameters cover WLAN (2.46–2.6 GHz), WiMAX (3.37–3.75 GHz), and HIPERLAN (5.2–5.87 GHz) based on ?10 dB reflection coefficient and ?24 dB isolation is achieved between antenna ports. Good agreement is obtained between the simulated and measured results. © 2015 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:510–521, 2015.     

氩氧比对ZnO薄膜特性的影响与紫外探测器的研制

利用射频磁控溅射技术在SiO2／n—Si和玻璃衬底上制备ZnO薄膜,研究了溅射气体氩氧比对薄膜特性的影响,在氩氧比为2：3下所制备的ZnO薄膜c轴择优取向相对较好,薄膜的颗粒随氩氧比的增加而增大,所制备的薄膜在可见光均具有较高的透射率,吸收边在360-380nm附近;并在以SiO。／n—Si为衬底,氩氧比为2：3,经过退火处理的ZnO薄膜上制作Ag-ZnO—Ag肖特基MSM叉指结构的紫外探测器,所制作的探测器在5V偏压下漏电流为3．3×10^-8A,在紫外波段有较高的响应度,光响应度峰值在365nm附近。     

A monitoring system for detecting repeated packets with applications to computer worms

We present a monitoring system which detects repeated packets in network traffic, and has applications including detecting computer worms. It uses Bloom filters with counters. The system analyzes traffic in routers of a network. Our preliminary evaluation of the system involved traffic from our internal lab and a well known historical data set. After appropriate configuration, no false alarms are obtained under these data sets and we expect low false alarm rates are possible in many network environments. We also conduct simulations using real Internet Service Provider topologies with realistic link delays and simulated traffic. These simulations confirm that this approach can detect worms at early stages of propagation. We believe our approach, with minor adaptations, is of independent interest for use in a number of network applications which benefit from detecting repeated packets, beyond detecting worm propagation. These include detecting network anomalies such as dangerous traffic fluctuations, abusive use of certain services, and some distributed denial-of-service attacks. P. van Oorschot(Ph.D. Waterloo, 1988) is a Professor in the School of Computer Science at Carleton University, and Canada Research Chair in Network and Software Security. He is the founding director of Carleton's Digital Security Group. He has worked in research and development in cryptography and network security, including at Bell-Northern Research (Ottawa), and Entrust Technologies (Ottawa) as VP and Chief Scientist. He is coauthor of the standard reference Handbook of Applied Cryptography. His current research interests include authentication and identity management, network security, software protection, and security infrastructures. J.-M. Robertis a Principal Security Researcher at Alcatel in Ottawa, Ontario. His research interests are network and telecom infrastructure security, focusing mainly on denial-of-service attacks and worm propagation. Previously, Dr. Robert worked as Security Director for the North American Development Center of Gemplus International as well as Professor at the Université du Québec à Chicoutimi. Dr. Robert received a Ph.D. in Computer Science from McGill University. M. Vargas Martinis an Assistant Professor at the University of Ontario Institute of Technology (Oshawa, Canada), with faculty appointments in Business and Information Technology, as well as Engineering and Applied Science. He was previously a post-doctoral researcher at Carleton University supported in part by Alcatel Canada. He holds a Ph.D. in Computer Science (Carleton University, 2002), a Masters degree in Electrical Engineering (Cinvestav, Mexico, 1998), and a Bachelor of Computer Science (Universidad Autónoma de Aguascalientes, Mexico, 1996). His current research interests include network and host-based intrusion detection and reaction, mitigation of denial-of-service (DoS) and distributed DoS attacks, Web modeling and optimization, Internet connectivity, and interconnection protocols.     

A half cut design of low profile UWB planar antenna for DCS/PCS/WLAN applications

A miniaturized half cut coalesced kite shaped printed antenna is presented for the ultrawide band (UWB) characteristics. The proposed design bears a compact and small physical dimension of 25 (L) × 9 (W) × 1.6 (h) mm³. This structure produces higher impedance bandwidth as compared to the corresponding full structure of the antenna design. The variation of ground plane dimension is studied to get the optimized results of the antenna. The measured impedance bandwidth (return loss <10 dB) of the proposed antenna is found to be 16.12 GHz in the frequency range 1.02 to 17.14 GHz. The average measured gain for this design is 3.12 dBi for the entire band of operation. The far field radiation patterns are also presented at 1.18, 3.1, 6.85, and 10.6 GHz. The antenna performances are first analyzed by the CST Microwave Studio, the simulation software based on finite integration technology (FIT) and then the optimized structure is fabricated for the measurements. The proposed design structure reveals the recent state of art by using the half cut technique which not only miniaturizes the size but also covers the whole UWB range to be used for many wireless systems.