电荷测量与时序逻辑电路的研究

中国科学院近代物理研究所大科学工程HIRFL-CSR（Heavy Ion Research Facility at LanZhou-Cooling Storage Ring兰州重离子冷却储存环）已建成并处于调试和验收阶段，实验探测系统也正在建设当中。CSRm实验探测系统由外靶系统和内靶系统构成，主要用于核物理实验研究。CSRm TOF测量系统是现阶段CSRm实验探测系统的主要任务之一。 针对CSRm TOF测量系统电荷测量部分，论文阐述了一种采用前端ASIC-SFE16（Saclay Front End 16）芯片实现电荷测量的新型方法。它替代了采用分立元件和电子学插件构建系统的传统方法，着重解决了近代核物理实验中越来越突出的多路多道需求和高性能指标要求。根据我所多丝漂移室探测器的实际情况，我们设计了基于ASIC芯片的电荷测量前端电路板，结合中国科技大学的时间测量数字获取板，我们初步完成了对系统软硬件的测试，给出的实验室性能测试指标，为其在实验探测系统中的应用奠定了坚实的基础。 同时为了选出测量中的有用事例，需要进行事例判选，因此我们研制了多路延迟/脉宽调节时序逻辑电路，主要功能是针对提供的多路逻辑时序信号进行延迟和脉宽调节，支持NIM负信号输入和输出。 文中最后一部分论述了根据在调试过程中出现的实际问题所提出的解决方法，主要是针对电路的可靠性设计和噪声的处理

用于多举物理实验中的多重逻辑单元的研制

本文全面地论述了用于多举物理实验中的多重逻辑单元的研制开发及这一系统的结构、电路原理、性能和结论。论文前一部分阐明了研制开发的背景及符合测量的一般原理和方法，后一部分就多重逻辑单元的电路原理、可靠性设计、性能、结论展开论述。用于多举物理实验中的多重逻辑单元是一个可广泛适用于数据获取系统中用作事件触发发生器的NIM插件，它对具有众多相关参数的多举物理实验的实验数据进行有效逻辑处理及筛选。它根据预置的符合重数“N”的大小，输出一个NIM信号“OUT”去触发数据获取系统和ADC（或TDC），使它们只对产生≥N重符合的事件的实验信号进行数据转换，而忽略掉小于N重符合的事件，进而根据“N”值大小的变化得到符合事件的多重性及其分布。并从而使得后台数据获取系统的计算机能更容易和快速地对实验数据进行筛选和获取，去除掉大量无用数据，筛选掉大量低符合重数的事件，提高了实验的效率节省了珍贵的束流时间，为后台数据获取系统的计算机节省大量的存储空间。

多路信号处理与QDC门信号产生逻辑插件的研制

本论文描述了多路信号处理与QDC（电荷数字转换器）门信号产生逻辑插件的研制过程。该逻辑插件的逻辑电路和模拟电路都经过了精心的设计和调试。核物理研究沿着激发能、核自旋及核同位旋三个自由度深入开展，产生了核物理研究中许多新的前沿领域。随着入射能量的增加，开放的反应道增多，多重探测器投入使用，使核物理实验的数据参数已经从几十路上升到上千路，即需要电子学工作者研制和开发一些高速触发、高密度、高稳定性的电子学硬件系统。本论文描述的多路信号处理与QDC门信号产生逻辑插件，主要用于产生QDC的开门信号。该电路系统早十六路并行、独立的高速放大单元电路、高速比较单元电路、延迟和脉宽成形单元电路、逻辑信号扇出单元电路、触发指示单元电路及多路模拟信号求和单元电路构成。该逻辑插件可接收≥ 20mv的小辐度输入信号而产生32路标准ECL（高电平-0.8V，低电平-1.6V）互补输出逻辑信号。输出ECL逻辑信号用于产生QDC的门控信号。该插件的多路模拟信号求和单元电路对每路输入信号可产生幅度为50mv的输出信号。该输出信号可用于多重符衙事件的鉴别和产生trigger触发信号。总的来说，多路辐度信号处理与QDC门信号产生逻辑插件不仅适用于重离子核物理实验中产生QDC开门信号，也可用于其它核物理实验的多重符合事件的鉴别。该插件的研制成功为多参数获取系统提供了一个良发的前端硬件设备。

Measures for describing the size distribution of sediments

Numerous measures are used in the literature to describe the grain-size distribution of sediments. Consideration of these measures indicates that parameters computed from quartiles may not be as significant as those based on more rigorous statistical concepts. In addition, the lack of standardization of descriptive measures has resulted in limited application of the findings from one locality to another. The use of five parameters that serve as approximate graphic analogies to the moment measures commonly employed in statistics is recommended. The parameters are computed from five percentile diameters obtained from the cumulative size-frequency curve of a sediment. They include the mean (or median) diameter, standard deviation, kurtosis, and two measures of skewness, the second measure being sensitive to skew properties of the "tails" of the sediment distribution. If the five descriptive measures are listed for a sediment, it is possible to compute the five percentile diameters on which they are based (phi 5 , phi 16 , phi 50 , phi 84 , and phi 95 ), and hence five significant points on the cumulative carve of the sediment. This increases the value of the data listed for a sediment in a report, and in many cases eliminates the necessity of including the complete mechanical analysis of the sediment. The degree of correlation of the graphic parameters to the corresponding moment measures decreases as the distribution becomes more skew. However, for a fairly wide range of distributions, the first three moment measures can be ascertained from the graphic parameters with about the same degree of accuracy as is obtained by computing rough moment measures.

两种种植密度下施肥对冬小麦生物学性状及产量的影响

以土垫旱耕人为土为供试土壤,采用大田试验,研究半湿润农田生态系统两种种植密度下不同施肥处理对冬小麦生物学性状及子粒产量的影响。试验设两种种植密度:常规密度(播种量为150.0kg/hm~2)和低密度(播种量为90.0kg/hm~2)。常规密度设7个施肥处理,即不施肥(CK),单施磷肥(PN0),单施氮肥(P0N135)和在施P的基础上每公顷施N45、90、135和180kg(即PN45、PN90、PN135、PN180);低密度施肥处理设不施肥(CK)、单施磷(PN0)、单施氮(P0N135)和氮磷配施(PN135)。结果表明,低密度时,CK处理分蘖数最低(每株平均3.2个),PN135分蘖数最高(每株平均6.9个);常规密度时,仍以CK分蘖数最低(每株平均3.2个),PN180分蘖数最大(每株平均6.8个)。低密度下,PN0和CK与P0N135和PN135间植株绿叶面积差异达显著水平(P<0.05),以PN135绿叶面积最大,PN0绿叶面积最小;常规密度下,PN180绿叶面积最大,为80.7cm~2/单茎,PN0绿叶面积最小,为44.4cm~2/单茎。低密度时,CK旗叶面积最小,PN135旗叶面积最大;常规...

黄土高原水蚀风蚀交错区治理的重要性与紧迫性

在全国范围划分水蚀、风蚀和冻融侵蚀三大侵蚀类型区基础上 ,提出进一步划分水蚀风蚀交错区的必要性及重要意义。黄土高原的强烈侵蚀中心出现在水蚀风蚀交错区 ,该区为黄河粗泥沙的主要来源区 ,生态环境脆弱 ,自然灾害频繁。该区又为世界级大型煤田蕴藏地 ,将建成我国 2 1世纪的能源重化工基地。强化水蚀风蚀交错区综合治理 ,对治黄及西部地区开发具有重大意义。

论数字黄土高原建设的若干问题

提出了“数字黄土高原”的概念 ,对其建设的必要性 ,发展的基础、目标、战略及其发展阶段 ,总体结构 (包括数据组成、数据库结构、投影方式、数据层的组织 ) ,和几个亟待研究的问题 ,包括数据标准与元数据体系、数据协调与集成方式、空间尺度的转换等 ,进行了初步的讨论。

黄土高原地区农田土壤水分高效调控技术

分析黄土高原节水农业的必要性 ,总结出黄土高原农业调水技术主要有 7大类 :培肥地力以肥调水 ,轮作倒茬调水 ,间隙休闲调水 ,抗旱育种调水 ,节水灌溉调水 ,径流农业调水 ,化学技术调水 ;指出在干旱、半干旱的黄土高原地区 ,利用农业调水技术是粮食增产增收的有效措施和必然趋势

Structural analysis of monoterpene glycosides extracted from Paeonia lactiflora Pall. using electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry and high-performance liquid chromatography/electrospray ionization tandem mass spectrometry

Paeoniflorin standard was first investigated by electrospray ionization Fourier transform ion cyclotron resonance tandem mass spectrometry (ESI-FTICR-MS/MS) using a sustained off-resonance irradiation (SORI) collision-induced dissociation (CID) method at high mass resolution. The experimental results demonstrated that the unambiguous elemental composition of product ions can be obtained at high mass resolution. Comparing MS/MS spectra and the experimental methods of hydrogen and deuterium exchange, the logical fragmentation pathways of paeoniflorin have been proposed. Then, the extracts of the traditional Chinese medicine Paeonia lactiflora Pall. were analyzed by high-performance liquid chromatography/electrospray ionization tandem mass spectrometry (HPLC/ESI-MS/MS). By comparison with the ESI-FTICR-MS/MS data of paeoniflorin, the isomers paeoniflorin and albiflorin in Paeonia lactiflora Pall. have been identified using HPLC/MS with CID in an ion trap and in-source CID. Furthermore, using the characteristic fragmentation pathways, the retention times (t(R)) in HPLC and MS/MS spectra, the structures of three other kinds of monoterpene glycoside compounds have been identified on-line without time-consuming isolation.

Studies on lignan constituents from Schisandra chinensis (Turcz.) Baill. fruits using high-performance liquid chromatography/electrospray ionization multiple-stage tandem mass spectrometry

A reversed-phase high-performance liquid chromatography-diode array detector-electrospray ionization multiple-stage tandem mass spectrometry (RP-HPLC-DAD-ESl-MSn) method has been developed for the detection and analysis of lignan constituents in the methanol extract from the fruits of Schisandra chinensis (Turcz.) Baill. RP-HPLC-DAD-ESI-MSn and electrospray ionization Fourier transform ion cyclotron resonance multiple-stage tandem mass spectrometry (ESI-FT-TCR-MSn) have been applied to investigate the characteristic product ions of four lignan reference compounds. Then, the logical fragmentation pathways of the lignans have been proposed. By comparing the retention time (t(R)) of HPLC, the ESI-MSn data and the structures of analyzed compounds with the data of reference compounds and in the literature, 11 peaks in HPLC have been unambiguously identified and another 5 peaks have been tentatively identified or deduced. Also, in the present paper, the extracted ion chromatograms (EIC) have been used to analyze the lignan isomers. The experimental results demonstrate that RP-HPLC-DAD-ESI-MSn is a specific and useful method for the identification of the lignan constituents and their isomers.

Analysis of strychnos alkaloids using electrospray ionization Fourier transform ion cyclotron resonance multi-stage tandem mass spectrometry

The fragmentations of four strychnos alkaloids have been investigated by electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI-FTICR-MS) in the positive ion mode. Experiments using multi-stage tandem mass spectrometry (ESI-FT-ICR-MSn) allowed us to obtain precise elemental compositions of product ions at high mass resolution. The experimental data demonstrated that the nitrogen bridge and the coordinated oxygen atom on the nitrogen bridge in the alkaloid compounds were the active sites in the MS2 fragmentations. The loss of CH3 or the OCH3 group in those alkaloids, which have an OCH3 substituent, was the dominant fragmentation mode in the MS3 fragmentations. Logical fragmentation schemes for strychnos alkaloids have been proposed and these should be useful for the identification of these compounds.

Functional characterization of sll0659 from Synechocystis sp PCC 6803

Synchocystis sp. PCC 6803 lacks a gene for the any known types of lycopene cyclase. Recently, we reported that sll0659 (unknown for its function) from Synechocystis sp. PCC6803 shows similarity in sequence to a lycopene cyclase gene-CruA from Chlorobium tepidum. To test, whether Sll0659 encoded protein serves as lycopene cyclase, in this study, we investigated the carotenoids of the wild types ans mutants, In the sll0659 deleted mutant, there is no blockage at the lycopene cyclization step. Our results demonstrate that sll0659 does not affect lycopene cyclization. However, the ultrastructure of mutants suggests the involvement or necessity of sll0659 in the cell division.

高原鼠兔的季节性繁殖

A nnual changes of the rep roduct ive act ivity in adult male p lateau p ika (Ochotona curzoniae) , a small endemic mammal in Q inghai2T ibet P lateau, w ere invest igated from J anuary to December, 1991. A ll of the animals w ere k illed and decap itated during the nigh t (23:00～ 24:00) and the p lasma, p ineal glands, testes ep ididym is, sem inal vesicles, deferent ducts were co llected and used for biochemical, and histo logical studies. Significant changes associated with seasonal cycles were found. (1) In February～ early April, the restoration phase, the weights of testes, epididym ides and deferent ducts were increased; the process of sperm atogenesis was strengthened and testo sterone level in plasma was increased, but the pineal weight and its melatonin content were decreased. (2) During the middle of April～ late May, the sexually active phase, a significant elevation of gonadal activity was observed. In this period, gonadalw eights were increased, spermatogenesis was completed, pineal weights were decreased and melatonin contents were fluctuated at alow level. These results suggested the increasing in sexual activity as well as in the ability of testo sterone secretion. (3) A striking reduction of test icular activity appears in June～A ugust. In this inhibition phase, gonada lweight, process of sperm atogenesis, plasma testo sterone level were decreased while the pineal weight and pineal melatonin content were increased. (4) During Sep tember～ J anuary, the sexually quiescent phase, declining in weights of testes and epididymides, arrest of spermatogenesis, decreasing of plasma testo sterone concent ration, fluctuating in pineal weights and increasing in pinealmelatonin level were observed. Our findings indicated that the male pikas under natural conditions exhibited an annual rep roductive cycle. A possible relationship between pineal activity and reproductive function was also suggested.

ISSR analysis of genetic diversity of the Qinghai-Tibet Plateau endemic, Rhodiola chrysanthemifolia (Crassulaceae)

Inter-simple sequence repeat markers (ISSR) were used to estimate genetic diversity within and among 10 populations of Rhodiola chrysanthemifolia along Nianqingtangula Mountains and Brahmaputra, a species endemic to the Qinghai-Tibet Plateau and an endangered medicinal plant. Of the 100 primers screened, 13 produced highly polymorphic DNA fragments. Using these primers, 116 discernible DNA fragments were generated of which 104 (89.7%) were polymorphic, indicating substantial genetic diversity at the species level. Genetic diversity measured by the percentage of polymorphic bands (PPB) at the population level ranged from 21.97% to 48.8%. Analysis of molecular variance (AMOVA) showed that the genetic variation was found mainly among populations (77.3%), but no regional differentiation was discernible. Variance within populations was only 22.7%. The main factor responsible for this high level of differentiation among populations is probably the historical geographical and genetic isolation of populations in a harsh mountainous environment. Concerning the management of R. chrysanthemifolia, the high genetic differentiation of populations indicates the necessity of conserving the maximum possible number of populations. (c) 2006 Elsevier Ltd. All rights reserved.

节能有效的无线传感器网络状态信息收集算法

网络状态信息收集协议既要保证信息收集的准确性、实时性,又要保证协议算法的轻量级特性。为解决上述矛盾问题,提出了一种轻量级的、能量有效的、基于无损聚合的层次分簇数据收集机制(QTBDC)。QTBDC首先对网络节点编码并在节点间建立起一个逻辑层次簇结构,然后利用各个子簇状态数据的相似性和编码的连续性,实现了网内无损聚合。该监测机制使得网络状态信息的收集在不丢失数据细节信息的情况下,数据通信量大大减少。经过仿真分析表明,该方法与现有经典数据收集方法相比,实现了节能,延长了网络的生命期。