医用回旋加速器电源控制器软件设计

医用回旋加速器控制系统是在HIRFL—CSR控制系统上总结完善出来的，医用回旋加速器控制系统是一个基于网络的分布式控制系统，它由许多分控制系统组成。磁铁电源控制系统是回旋加速器控制系统中一个重要部分，它是一个集波形发生、数据采集、状态监测与一体的系统。输出波形的参数由实验需要而计算得到。因为加速器所有的运行激励都由电源所控制，电源控制着磁场的状态，磁场的状态决定着加速器的状态，所以控制系统的直接控制对象就是磁场电源。在整个控制系统中最重要的就是控制波形的同步和波形的精度，这是同步加速器控制系统的关键所在。波形的同步由同步时序系统控制，这是回旋加速器成功运行的先决条件。数据的采集、电源状态的监测由数据采集模块CPLD+ARM负责完成，CPLD与ARM控制器结合，形成数据的上行通道。采集到的数据均存放在中央控制室的数据库中，以供参考、后期分析及应用。论文论述了对医用回旋加速器电源控制器软件的设计实现。对磁铁电源控制系统，主要从系统的结构、I/O部件的硬件设计和软件设计这几个方面进行论述；对软件系统，主要描述各类硬件驱动设计、对数据预处理和与数据库通信的设计实现。本文的工作在医用回旋加速器控制系统中具有很重要的意义，为重离子束治疗肿瘤做了基础准备。从测试及验收结果来看，我们对控制系统的优化不仅在硬件结构上，还是在软件设计实现上都达到了设计要求

CSR束流快引出控制系统研究与实现

HIRFL—CSR（兰州重离子冷却储存环）控制系统由许多子控制系统组成，磁场电源控制系统是其重要的组成部分。为实现将加速后的束流引出到实验环和外靶实验终端，需要设计一套完善的束流快引出电源控制系统。我们利用自行研制的高实时性DSP控制器，并结合先进的ARM嵌入式网络技术，构建了一个基于以太网技术的分布式电源控制系统。对于整个控制系统，本文从分布式系统总体结构，I/O部件硬件构成和软件系统编程，同步时序系统的原理与具体实现等多个方面进行论述，最后给出在试验平台和现场的测试结果。通过现场测试与分析，本系统完全满足了HIRFL-CSR大科学工程对控制系统的要求。本控制系统的技术难点为：对束团位置的精确定位和对分布式控制系统中各I/O部件的操作同步。主要技术创新有：在加速器控制领域采用先进的ARM+DSP的嵌入式控制方式；利用高速FPGA数字技术实现Kicker的定时触发

总线控制器的设计及其在CSR控制系统中的应用

HIRFL-CSR(兰州重离子冷却储存环)是国家“九五”重大科学工程之一。CSR控制系统是保证CSR正常运行的重要环节。这是一个基于以太网的分布式控制系统，它由两部分组成：总体控制服务器系统和前端控制服务器系统。 本文介绍了应用于CSR前端控制系统中的嵌入式总线控制器。首先介绍了嵌入式总线控制器的硬件设计方案。系统以32位高速双以太网处理器JUPITER为核心。JUPITER是一款低成本、高性能、建立在以太网系统基础之上的处理器。该系统的外阴电路主要包括存储模块、接日模块、总线控制模块。接口模块有RS485、RS232和网络接口电路。其次论述了嵌入式操作系统uClinux的体系结构以及uClinux与标准Linux的不同之处。论文从uClinux的内核结构出发，讨论了源代码的组织结构，概括分析了uClinuxlj勺内存管理、进程管理。最后介绍了uClinujx统的移植方法和应用实现。uClinux移植主要包括引导装载程序、uClinux内核和文件系统三个部分。在引导装载程序的移植过程中，论文重点给出了一种固化引导装载程序的方法；在uClinux内核移植中，讨沦了交叉编译环境l为建立和uClinux内核配置方法，总结了uClinux内核移植的层次结构和具体的移植过程。沦文通过对嵌入式处理器的分析，以及对嵌入式操作系统移植的探讨，展示了嵌入式系统开发的核心技术，对眠入系统的开发应用具有一定的实际意义。

一种Post-WIMP界面：PGIS的实现

随着计算机应用从桌面环境扩展到移动环境，计算机用户从专业化走向大 众化，传统的 WIMP界面的缺点逐渐体现出来。笔式用户界面作为 Post-WIMP 界面的一种重要形式，具有自然、和谐的交互特性，成为当前研究的热点之一。 针对这一方向，本文对笔式用户界面范式展开了研究。首先，本文阐述了一种 新的基于笔交互的界面范式 PGIS，定义了纸、小工具等交互组件，以及各种组 件的显示形态及交互形式。然后，实现了 PGIS 界面，包括交互对象的管理、 显示等内容。最后，详细介绍了 PGIS 界面的使用过程，并用一个应用实例加 以验证。为了支持上层应用程序的可移植性和可维护性，PGIS界面的使用采用 了模型驱动构架的开发思想。目前，我们基于 PGIS 界面开发了几款优秀的笔 式交互软件，如幼儿教学系统、便签本系统、篮球战术板系统等。这些系统完 全满足用户对笔交互应用程序的需求，目前可在 Linux 系统、Windows 系统等 多种系统上运行。PGIS界面范式的可行性也因此得到了很好的验证。 本文的主要内容有以下几点： 1. 阐述了一种 Post-WIMP范畴下的新的界面范式：PGIS。 本文在对Post-WIMP界面做了充分地理解和分析的基础上，阐述了一种新 的界面范式：PGIS。这是一种基于笔交互的界面范式，文中对该范式的纸笔隐 喻方式、所包含的内容、各交互组件的表现形式、以及各组件间的静态及动态 关系做出了详细的描述。 2. 实现了PGIS界面。 为了验证PGIS界面范式的可行性，并直接支持基于 PGIS范式的应用程序 开发，本文详细介绍了PGIS界面的实现细节，其中包括PGIS界面中所包含的 元素、PGIS界面中交互对象的显示、交互对象的管理、以及交互对象对基本原 语的转换和响应。 3. 介绍了 PGIS界面的使用过程。 整个使用过程采用模型驱动架构的思想，引入对以下三个子模块的调用： 与平台相关的底层核心库和 PGIS 引擎、与平台无关的场景设计工具。这三个 子模块决定了上层应用程序的可移植性和可维护性。另外，场景设计工具提供 了代码自动生成的功能，大幅度缩短了应用程序的开发周期。 4. 实现了一个基于 PGIS界面的幼儿教学系统。 为了说明 PGIS界面的使用流程，本文设计并实现了一个基于PGIS界面的 幼儿教学系统。在开发过程中，大部分工作在场景设计工具中快速完成，小部 分工具集中在数据管理库、场景任务库的开发上。该系统的评估结果很好地验 证了 PGIS界面范式的可行性。

基于事件的文件系统恢复技术

在现代文件系统中，用户只能访问文件和目录的当前版本，而无法查看文件和目录的改变过程。用户可能无意地或错误地对文件执行了删除或修改操作，或者执行了一段恶意脚本，导致一系列文件遭到破坏。如果能够记录文件和目录的修改过程，并且可以方便地恢复某次操作破坏的一系列文件，这对用户是相当有帮助的。本文把一个进程在其执行过程中对文件的一系列修改称为一个事件。 文件系统可以通过文件版本化技术来记录文件的修改过程。文件版本化技术包括两种：快照技术和单文件版本化技术。这两种技术都没有提供用户一种方便有效的方法来撤销一个进程对多个文件的一系列修改，无法撤消一个事件对文件的改变。所以，本文在单文件版本化技术的基础上提出了基于事件的文件系统恢复技术，并设计实现了一个具有事件恢复功能的文件系统GobackFS（Go back file system，简称GobackFS）。本文的主要贡献体现在以下几点： (1) 针对如何恢复一个进程在其运行过程中改变的一系列文件这一问题，本文提出了基于事件的文件系统恢复技术，并通过一个实例——GobackFS文件系统，给出了基于事件的文件系统恢复技术的一种设计与实现。 (2) 对用户完全透明的系统设计和实现。GobackFS文件系统透明地创建文件版本，记录文件的改变过程。在GobackFS文件系统中，如果文件以写标志打开时，创建一个新的文件版本，在文件每一次打开和关闭期间最多创建一个新版本。文件的访问权限和所有权发生变化时，创建新的文件子版本。GobackFS文件系统透明地记录改变文件的事件信息。在创建文件版本和子版本时，记录触发文件版本创建的事件信息。 (3) 提供了简单易用的使用接口。在GobackFS文件系统中，用户可以通过一条简单的命令来查看某段时间内哪些事件对文件做了更改，某个事件对哪些文件做了更改，并且通过一条命令就可以撤销某个事件对一系列文件的更改。另外，用户还可以方便的查看单个文件的所有保留版本，并可以恢复到任意版本。 (4) 方便移植的系统架构。GobackFS文件系统基于FUSE框架实现，是一个用户空间文件系统，可以方便地移植到多个Unix/Linux系统中使用，而不需要对内核做任何修改，也不需要复杂的配置。

The effect of La or Ce on ageing response and mechanical properties of cast Mg-Gd-Zr alloys

Mg-8Gd-0.6Zr-1RE (RE = La or Ce, wt.%) alloys were prepared by casting. The microstructures, age hardening behavior and mechanical properties were investigated. The results show that the addition of 1 wt.% La or Ce to a Mg-8Gd-0.6Zr alloy reduces the dendrite arm spacing and slightly improves the mechanical properties and age hardening response.

Investigation of the dewetting inhibition mechanism of thin polymer films

The mechanism of inhibition of polymer film dewetting is investigated by adding a star comb-like polymer, four-arm P(S-ran-VB-g-PMMA), to PS film and PMMA film on different substrates. It is found that the mechanism of inhibition of polymer film dewetting is kinetic in nature, and is related to the miscibility between the additional compound and the polymer film. On addition to the miscible system [four-arm P(S-ran-VB-g-PMMA) and PMMA], the star comb-like polymers can increase the resistant force of dewetting with hole growth and inhibit the dewetting process of the thin polymer film by enrichment in the rim.

Macrocycle-Terminated Core-Cross-Linked Star Polymers: Synthesis and Characterization

We have synthesized macrocyclic polystyrene- (PS-) terminated PS star polymers via a core-cross-linking approach in this work. A tadpole-shaped macrocyclic PS-linear-PS copolymer was synthesized at first via click chemistry and ATRP polymerization method. The "living" ATRP initiating chain-ends of the tadpole-shaped copolymers were linked together via ATRP polymerization with divinylbenzene to form a core-cross-linked macrocyclic star polymer. The number of arms attached to the macrocyclic star polymers was measured with NMR. and absolute molecular weights with gel permeation chromatography (GPC) with multiangle laser light scattering detector. These macrocyclic star polymers had a highly cross-linked core and many radiating arms. The shorter tadpole-shaped precursors caused core-cross-linked star polymers with higher molecular weights and more arm numbers. The macrocycle-terminated core-cross-linked star polymers showed two glass transition temperatures, one arising from the linear branches and another from the macrocycles.

Influence of molecular topology on the static and dynamic properties of single polymer chain in solution

The influence of molecular topology on the structural and dynamic properties of polymer chain in solution with ring structure, three-arm branched structure, and linear structure are studied by molecular dynamics simulation. At the same degree of polymerization (N), the ring-shaped chain possesses the smallest size and largest diffusion coefficient. With increasing N, the difference of the radii of gyration between the three types of polymer chains increases, whereas the difference of the diffusion coefficients among them decreases. However, the influence of the molecular topology on the static and the dynamic scaling exponents is small. The static scaling exponents decrease slightly, and the dynamic scaling exponents increase slightly, when the topology of the polymer chain is changed from linear to ring-shaped or three-arm branched architecture. The dynamics of these three types of polymer chain in solution is Zimm-like according to the dynamic scaling exponents and the dynamic structure factors.

CE with electrochemical detection for investigation of label-free recognition of amino acid amides by guanine-rich DNA aptamers

In this work, we report a simple and effective investigation into adaptive interactions between guanine-rich DNA aptamers and amino acid amides by CE with electrochemical (EC) detection. Argininamide (Arm) and tyrosinamide (Tym) were chosen as model molecules. On a copper electrode, Arm generated a good EC signal in 60 mM NaOH at 0.7 V (vs Ag/ AgCl), while Tym. was detected well on a platinum electrode at 1. 3 V in 20 mM phosphate of pH 7.0. Based on their EC properties, the ligands themselves were used as indicators for the adaptive interactions investigated by CE-EC, making any step of labeling and/or modification of aptamers with indicators exempted. Hydrophilic ionic liquid was used as an additive in running buffer of CE to improve the sensitivity of Arm detection, whereas the additive was not used for Tym. detection due to its negative effect. Two guanine-rich DNA aptamers were used for molecular recognition of Arm and Tym. When the aptamers were incubated with ligands, they bound the model molecules with high affinity and specificity, reflected by obvious decreases in the signals of ligands but no changes in those of the control molecules. However, the ligands were hardly affected by the control ssDNAs after incubation. The results revealed the specific recognition of Arm and Tym. by the aptamers.

Phase diagram data for several salt plus salt aqueous biphasic systems at 298.15 K

Phase diagrams corresponding to aqueous biphasic systems of salt (the organic ionic liquid of salts [C(4)mim]Cl, [C(6)mim]Cl, and [C(8)mim]Cl) + salt (K3PO4, K2CO3) + water were determined at 298.15 K. The binodal curve was fitted to the Merchuk equation. Tie lines assigned from mass phase ratios according to the lever arm rule were satisfactorily described using the Othmer-Tobias and Bancroft equations.

Structural features of the L-argininamide-binding DNA aptamer studied with ESI-FTMS

The 24-mer DNA aptamer of Harada and Frankel ( Harada, K.; Frankel, A. D. EMBO J. 1995, 14, 5798-5811) that binds L-argininamide (L-Arm) was studied by electrospray ionization Fourier transform mass spectrometry (ESI-FTMS). This DNA folds into a stem and loop such that the loop is able to engulf L-Arm. As controls, two derivatives of the same base composition, one with the same stem but a scrambled loop and the other with no ability to form a secondary structure, were studied. The two DNAs that could fold into stem-loop structures showed a more negatively charged distribution of ions than the linear control. This tendency was preserved in the presence of ligand; complexes expected to have more secondary structure had ions with more negative charges. Distinct species corresponding to no, one, and two bound L-Arm molecules were observed for each DNA. The fractional peak intensities were fit to a straightforward binding model and binding constants were obtained. Thus, ESI-FTMS can provide both qualitative and quantitative data regarding the structure of DNA and its interactions with noncovalent ligands.

MISCIBILITY, MICROSTRUCTURE, AND DYNAMICS OF BLENDS CONTAINING BLOCK-COPOLYMER .1. MISCIBILITY OF BLENDS OF HOMOPOLYSTYRENE WITH STYRENE-BUTADIENE BLOCK-COPOLYMERS

The miscibilities of blends of homopolystyrene/styrene-butadiene/styrene (PS/SBS) and PS/SB-4A (4-arm star block copolymer) have been studied by dynamic mechanical analysis (DMA) and C-13 CPMAS NMR techniques. The results indicate that the miscibilities o

MISCIBILITY, MICROSTRUCTURE, AND DYNAMICS OF BLENDS CONTAINING BLOCK-COPOLYMER .2. MICROSTRUCTURE OF BLENDS OF HOMOPOLYSTYRENE WITH STYRENE-BUTADIENE BLOCK-COPOLYMERS

The microstructures of styrene-butadiene triblock (SBS) and styrene-butadiene four-arm star block (SB-4A) copolymers and their blends with homopolystyrene (PS) of different molecular weights, MPS, have been investigated by means of small-angle X-ray scatt

Differences in the rDNA-bearing chromosome divide the Asian-Pacific and Atlantic species of Crassostrea (Bivalvia, Mollusca)

Karyotype and chromosomal location of the major ribosomal RNA genes (rDNA) were studied using fluorescence in situ hybridization (FISH) in five species of Crassostrea: three Asian-Pacific species (C. gigas, C. plicatula, and C. ariakensis) and two Atlantic species (C. virginica and C. rhizophorae). FISH probes were made by PCR amplification of the intergenic transcribed spacer between the 18S and 5.8S rRNA genes, and labeled with digoxigenin-11-dUTP. All five species had a haploid number of 10 chromosomes. The Atlantic species had 1-2 submetacentric chromosomes, while the three Pacific species had none. FISH with metaphase chromosomes detected a single telomeric locus for rDNA in all five species without any variation. In all three Pacific species, rDNA was located on the long arm of Chromosome 10 (10q)-the smallest chromosome. In the two Atlantic species, rDNA was located on the short arm of Chromosome 2 (2p)-the second longest chromosome. A review of other studies reveals the same distribution of NOR sites (putative rDNA loci) in three other species: on 10q in C. sikamea and C. angulata from the Pacific Ocean and on 2p in C. gasar from the western Atlantic. All data support the conclusion that differences in size and shape of the rDNA-bearing chromosome represent a major divide between Asian-Pacific and Atlantic species of Crassostrea. This finding suggests that chromosomal divergence can occur under seemingly conserved karyotypes and may play a role in reproductive isolation and speciation.