Fabrication and analysis of 2x2 thermo-optic SOI waveguide switch with low power consumption and fast response by anisotropy chemical etching

A low power consumption 2 x 2 thermo-optic switch with fast response was fabricated on silicon-on-insulator by anisotropy chemical etching. Blocking trenches were etched on both sides of the phase-shifting arms to shorten device length and reduce power consumption. Thin top cladding layer was grown to reduce power consumption and switching time. The device showed good characteristics, including a low switching power of 145 mW and a fast switching speed of 8 +/- 1 mus, respectively. Two-dimensional finite element method was applied to simulate temperature field in the phase-shifting arm instead of conventional one-dimensional method. According to the simulated result, a new two-dimensional index distribution of phase-shifting arm was determined. Consequently finite-difference beam propagation method was employed to simulate the light propagation in the switch, and calculate the power consumption as well as the switching speed. The experimental results were in good agreement with the theoretical estimations. (C) 2004 Elsevier B.V. All rights reserved.

Coherent transport through a quantum dot embedded in a double-slit-like Aharonov-Bohm ring

Coherent transport through a quantum dot embedded in one arm of a double-slit-like Aharonov-Bohm (AB) ring is studied using the Green's function approach. We obtain experimental observations such as continuous phase shift along a single resonance peak and sharp inter-resonance phase drop. The AB oscillations of the differential conductance of the whole device are calculated by using the nonequilibrium Keldysh formalism. It is shown that the oscillating conductance has a continuous bias-voltage-dependent phase shift and is asymmetric in both linear and nonlinear response regimes.

多功能车辆总线网络设备的设计与实现

随着高速列车在全世界范围内的应用日益广泛，列车通信网络成为重要的研究领域。而多功能车辆总线网络设备是列车通信网络的核心技术。传统的基于单片机或基于可编程片上系统的网络设备在实时性、可扩展性和可靠性等方面均存在较大的劣势，现场可编程逻辑门阵列和通用微处理器的组合为克服这一困难提供了新的解决方案。现场可编程逻辑门阵列是现在集成电路设计验证的主流技术，在设计成本、开发周期、可扩展性和可重构性等方面有着明显的优势，为实现高性能网络设备提供了新的实现方法。通用微处理器广泛应用于嵌入式系统，在低功耗、外设扩展、处理速度等方面表现尤为突出。 本文结合列车通信网络和多功能车辆总线的研究，系统介绍了多功能车辆总线网络设备及通讯协议栈的设计，阐述了系统开发的相关技术，并重点介绍了通讯协议栈的具体实现。多功能车辆总线网络设备基于现场可编程逻辑门阵列FPGA和通用微处理器ARM。协议栈链路下层协议和物理线路控制逻辑在时序、时延、可靠性和并发性等方面有严格要求，且此部分功能的算法相对简单，采用FPGA实现。协议栈链路上层协议和其他高层协议在多任务、存储和定时等方面有着诸多需求，且此部分功能的算法相对复杂，采用基于嵌入式实时操作系统RTEMS和ARM的软硬件平台实现。本课题已经完成了基于FPGA和ARM的多功能车辆总线网络设备及通讯协议栈，证明了该设计框架的可行性，为自主研发列车通信网络相关产品提供了一个良好的实例。

Comparative cytogenetics of bats (Chiroptera): The prevalence of Robertsonian translocations limits the power of chromosomal characters in resolving interfamily phylogenetic relationships

Although the monophyly of Chiroptera is well supported by many independent studies, higher-level systematics, e.g. the monophyly of microbats, remains disputed by morphological and molecular studies. Chromosomal rearrangements, as one type of rare genomic changes, have become increasingly popular in phylogenetic studies as alternatives to molecular and other morphological characters. Here, the representatives of families Megadermatidae and Emballonuridae are studied by comparative chromosome painting for the first time. The results have been integrated into published comparative maps, providing an opportunity to assess genome-wide chromosomal homologies between the representatives of eight bat families. Our results further substantiate the wide occurrence of Robertsonian translocations in bats, with the possible involvement of whole-arm reciprocal translocations (WARTs). In order to search for valid cytogenetic signature(s) for each family and superfamily, evolutionary chromosomal rearrangements identified by chromosomal painting and/or banding comparison are subjected to two independent analyses: (1) a cladistic analysis using parsimony and (2) the mapping of these chromosomal changes onto the molecularly defined phylogenetic tree available fromthe literature. Both analyses clearly indicate the prevalence of homoplasic events that reduce the reliability of chromosomal characters for resolving interfamily relationships in bats.

QUANTUM WAVE-GUIDE THEORY FOR MESOSCOPIC STRUCTURES

A one-dimensional quantum waveguide theory for mesoscopic structures is proposed, and the boundary conditions of the wave functions at an intersection are given. The Aharonov-Bohm effect is quantitatively discussed with use of this theory, and the reflection, transmission amplitudes, etc., are given as functions of the magnetic flux, the arm lengths, and the wave vector. It is found that the oscillating current consists of a significant component of the second harmonic. This theory is also applied to investigate quantum-interference devices. The results on the Aharonov-Bohm effect and the quantum-interference devices are found to be in agreement with previous theoretical results.

ACHT操作引起黑麦(Secale cereale)染色体的畸变和重建

用ACHT处理黑麦萌动种子，对修复前后材料的观察和分析结果表明：1. ACHT操作引起染色体数目变化和染色体断裂损失。在一定 条件和范围内，不同处理引起的这种变化具有显著差异，条件越剧烈，染色体数目变化的范围和频率愈大，断片发生的数量和频率 也愈高，同时修复前后染色体数目的变化范围和频率与断片发生的数量和频率以及它们的修复频率均表现明显的相关性。2. ACHT 操作引起染色体畸变的多样性。经ACHT处理后，胚根细胞染色体有4种断裂方式，包括着丝粒断裂、次溢痕断裂、长臂断裂和短臂 断裂等，其中着丝断裂频率最高；产生6种断片类型，包括有着丝粒和端粒的、有着丝粒而无端粒的、有部分着丝粒和端粒的、有 部分着丝粒而无端粒的、只有端粒的、既无着丝粒也无端粒的断片等。3. ACHT操作引起遗传结构重建的多样性。经ACHT处理后， 对修复24-72小时材料进行核型比较(按Stebbins 和 Levan 标准)和随体分析，处理细胞在染色体数目、大小、形态、位置等方面 均发生显著变化，说明ACHT处理使这些细胞的染色体结构和染色体组型发生了深刻变化。进一步通过Giemsa C— 带分析，观察到 多种重建染色体类型，包括易位型染色体、附加型染色体、无着丝粒染色体、化染色体、增加的m染色体以及某些带型特异的染色 体等。4. RAPD 分析从分子水平上验证了ACHT能有效地引起遗传结构的改变。所用10种引物对处理和对照材料基因组DNA的扩增产 物在条带数目、条带位置及带型特征等方面均有明显差异，其中4种引物出现条带减少，6种引物出现条带增加，后者还包括一个带 位移动。这说明两种材料的基因组DNA具有明显的RAPD反应多态性差异。This paper descripes some results draw on the basis of the observation and analysis on the rye before and after repaired through treating its budding seeds by ACHT in contrast to without ACHT: 1. ACHT manipulation caused the number variation and breakage damage of rye chromosome. Within certain conditions and timits, this phenomenon caused by different treats had signifcant difference: the more the treatment condition is drastie, the more the chageable range and frequence of rye chromosomae number, and so is the produced fragments. Meanwhile, there existed striking relationship among the changeable range and frequence of rye chromosome, the produced number and frequence of fragments and repairing frequence. 2. ACHT manipulafion engendered the diversify of rye chromosomal aberration. Four breakage patterns and six sorts of fragment were observed by watching the chromosome of the rye radicle treated by ACHT, including centric breakage (occuring in the highest frequence), secondary constriction breakage, long arm breakage and short arm breakage to the former, Comprising that with both centromere and telomere, that with centromere and without telomere, that with partial centromere and with telomere, that with partfial ceetromere and without telomere, that only with telomere and that neither with centromere nor with telomere, etc. 3. ACHT manipulation engendered the diversify or rye genetic structs reconstruction. Karureotype analysis(according to Stebbins and Levan) and satellite anaeysis were carried out to rye radicle through 24-72-hour-long recoverage after ACHT manipulation, which showed remarkable change happened on the rye chromosomal number、shape、arm ration and pattern, etc. and also on the satellite number、size、shape and location etc. Those indicated that ACHT manipulation engendered violent changes to rye chromatin structure and chromosome type. Further Giemsa C-banding analysis showed many types of reconstructed chromosome, such as translocation、addition、without centromere、st and other chromosome. 4. RAPD analysis checked the validity of ACHT on changing genetic structure of rye on the level of molecular biology. The treated and recovered rye has different amplifying band pattern by using IO valid arbitary primers selected from 40 comparing with the control.

微生物法生成辅酶Q10的研究

本文根据我们实验室建立的发酵产物中辅酶Q10定性定量检测方法，筛选得到一株可以代谢产生较多辅酶Q10的野生菌株放射形土壤杆菌(Agrobacterium radiobacter No.50)。 为了提高放射形土壤杆菌的辅酶Q10的产量，本实验利用液体培养研究了单因素对菌株辅酶Q10产量的影响，并用正交法确定了最佳液态发酵条件。最佳发酵培养基是：葡萄糖20g,蔗糖40g, 硫酸铵10g,玉米浆30g, 酵母膏3g，K2HPO4 3g,MgSO4.7H2O 1g，蒸馏水1000mL,pH 7.0-7.2。最佳发酵条件是：转接斜面菌种到种子培养基, 转速220r/min、温度28。C培养24h后，转入发酵培养基(250mL三角拼装液量为50mL，pH 7.0), 接种量为10％，转速220r/min、温度28。C，培养120h。在此条件下，菌体湿重约为50g/L，辅酶Q10含量约为20mg/L。 本文以放射形土壤杆菌为出发菌株进行诱变育种，以期获得辅酶Q10高产菌。根据微生物育种原理、参照辅酶Q10的代谢调控机制，以野生型放射形土壤杆菌(Agrobacterium radiobacter No.50)为出发菌株，采用紫外线和亚硝基胍复合诱变技术，依次筛选得到菌体提取物M抗性菌ARM－7、烟草提取物T抗性菌株ARMT-26、Vk3抗性菌株ARMTV-25、链霉素抗性菌株ARMTVS-32，菌株ARMTVS-32产量达到了36.8mg/L，与原始出发菌株相比，产量提高了77％。 研究了茄尼醇、对羟基苯甲酸、橘子皮提取物D、胡萝卜提取物E、烟草提取物对ARMTVS-32合成辅酶Q10的影响，结果表明这些物质对菌体合成辅酶Q10有一定促进作用，添加0.2g/L茄尼醇时，辅酶Q10含量提高了17%，达到了40.7mg/L；添加1.2g/L橘子皮提取物D时，辅酶Q10含量提高了13.8%，达到了39.6mg/L；添加0.5g/L胡萝卜提取物E时，辅酶Q10含量提高了25.3% ，达到了43.6mg/L；添加8g/L烟草提取物时，辅酶Q10含量提高了12.6%，达到了39.2mg/L。 Production of Coenzyme- Q10 (CoQ10) by fermentation is considered as a process with broad prospects.Quantitative Analysis of CoQ10 in the culture of microbe by TLC—UV spectrophotometry was developed, by using this method we got the strain Agrobacterium radiobacter,which was isolated from forest soil of southwest of China. The effect of the single factor on CoQ10-production ability of the strain was examined by liquid cultured, and its best optimum cultivation conditions were established by orthogonal method. The results showed that the optimum fermentation conditions were as following: carbon sources glucose 20g/L,sucrose 40g/L; nitrongen sources (NH4)2SO4 10g/L,maize liquid 30g/L;yeast extract 3g; K2HPO4 3g/L,MgSO4.7H2O 1g/L; initial pH was 7 and volume of medium(medium volume vs flask volume) was 50mL/500mL, incubating for 120h on a rotary shaker at 220 rpm and 28℃.Under these conditions, the biomass and CoQ10 concentration reached 50g/L and 20mg/L respectively. According to the biosynthesis mechanism of CoQ10 and breeding theory, CoQ10 over-production strains were screened by UV--NTG. mutation using Agrobacterium radiobacter No.50 as parent strain. A microbe-juice resistant mutant ARMTVS-32, which also could resist tobacco-juice, VK3 and streptomycin, was screened out from an agar plate. The CoQ10 content of ARMTVS-32 reached 36.8mg/L, which was 77% higher than the initial strain. In addition, We discussed the effects of some organic substrates on the synthesis of CoQ10 in ARMTVS-32. The results showed that solanesol, orange juice D, carrot juice E and tobacco juice could promote the CoQ10 accumulation in the cells. The CoQ10 content of ARMTVS-32 reached 40.7mg/L when added 0.2g/L solanesol,it reached 39.6mg/L when added 1.2g/L orange juice D，it reached 43.6mg/L when added 0.5g/L carrot juice E. it reached 39.2mg/L when added 8g/L tobacco juice.

冷却存储环虚拟加速器的数据交互系统

介绍了兰州重离子加速器冷却存储环(HIRFL-CSR)为重离子治癌而改造的控制系统中的数据交互系统,数据交互系统是CSR虚拟加速器的核心。该系统能实现对256个能量级的束流控制,为以后深层重离子治癌做好准备。系统主要采用Java,COM,Oracle,ARM,DSP,FPGA等技术实现了对磁铁电源的实时、同步控制,已达到对束流的控制及束流在不同能量级间的切换控制。该系统已经运行于冷却存储环主环(CS-Rm)的束流慢引出调试中,性能稳定,能满足物理人员的要求。

应用于同步加速器时序控制的片上可编程系统的设计

同步加速器对控制信号的时间约束要求非常严格,时序控制是加速器控制系统中十分重要的环节。在兰州重离子加速器冷却储存环(HIRFL-CSR)控制系统中,时序控制主要采用FPGA+ARM+linux+DSP的体系结构。本文介绍基于FPGA和uClinux操作系统的片上可编程系统(SOPC)的设计,可将目前ARM+LINUX的工作完全集成在FPGA内实现,省去专用ARM芯片。其最高工作频率可达185 MHz,硬件资源消耗不到4%。片上可编程系统的硬件处理器系统和操作系统都可根据具体需求重新裁剪和配置。SOPC技术在加速器物理以及其他领域有着非常广泛的应用前景。

兰州重离子冷却储存环束流踢轨控制系统

踢轨系统是一种以快速脉冲方式工作的以高压大电流驱动的特殊二极磁铁系统,用于环形加速器的束流注入和引出。简要介绍了在兰州重离子加速器冷却储存环上采用ARM+DSP+FPGA技术实现踢轨控制时序的方法,时间控制精度达ns量级。ARM主要控制信号的网络通讯,踢轨系统的时序精度控制主要由DSP结合FPGA技术完成。远程时序控制信号均通过光纤传输,同时对踢轨电源的电压给定采用信号隔离器及铁氧体以抑制脉冲干扰。经现场测试,系统可以安全稳定地实现束流踢轨的控制要求。

CSRe与RIBLLⅡ实时数据交互系统

介绍了国家重大科学工程项目——兰州重离子加速器冷却存储环(HIRFL-CSR)的实验环(CSRe)以及RIBLLⅡ的子系统——实时数据交互系统。该系统主要实现对前端电源设备的实时同步控制,具体的实现方法是从控制Web界面输入的前端控制设备所需的数据信息传送至中心Oracle数据库,再更新至前端服务器的Oracle数据库,随后传送至ARM板中的sqlite数据库,给DSP板提供输入数据信息,通过同步触发事例对电源设备进行同步实时控制。该系统正在RIBLLⅡ的测试中,运行正常、可靠性强、性能稳定。

RIBLLⅡ与CSRe中束流控制系统的设计

介绍了兰州重离子加速器冷却存储环(HIRFL-CSR)的实验环CSRe以及次级束线RIBLLⅡ中束流控制系统的设计。该系统主要采用了Java,COM,Oracle,ARM,DSP,FPGA等技术实现了对磁铁电源的实时、同步控制,已达到对束流的控制。该系统已经运行于现场的束流调试中,并在RIBLLⅡ的束流调试中运行正常、性能稳定。

基于FPGA的VME总线控制器及其驱动程序

本文论述了用于兰州重离子加速器冷却储存环(HIRFL-CSR)前端控制系统的总线控制器的FPGA设计及其基于ARM-Linux下的驱动程序设计。该总线控制器采用Altera公司的ACEX系列中的EP1K30实现,通过VME总线背板同其它VME设备(CPLD)通信,可读VME设备数据,监视电源运行状况,也可向VME设备发送命令和写数据,并且能够响应VME设备中断,读中断数据。为了能够通过AT91RM9200控制器访问VME总线控制器,必须为其编写相应的驱动程序。驱动程序定义了应用程序调用接口和数据格式,并实现了中断机制、多进程访问和数据的突发(burst)读写。

并行设备总线电源控制系统设计

为实现CSRe试验环磁铁电源的控制同步,采用32位ARM内核芯片技术结合DSP控制板方式,稳定可靠地实现控制数据流的传输和同步事例的收发。同时通过CPLD逻辑时序编程来设计eVME背板总线系统。本系统用嵌入式网络和并行总线技术可靠稳定实现数据的快速获取与给定。

基于AT91RM9200的触摸屏驱动及三点校正算法

凭借Internet的优势,随着性能的提高和价格的下降,嵌入式系统的应用也更加的普及和广泛.本文介绍了在ARM-Linux操作系统下,基于USB接口的五线电阻触摸屏的嵌入式驱动程序和一种可用于纠正一些常见机械性误差的触摸屏三点校准算法,驱动的编译配置和算法的实现。由于校准算法简单、灵活,用软件实现,可降低嵌入式系统中的成本,提高产品质量。