46 resultados para Analog multipliers.


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Two kinds of quantum computation systems using artificial molecules: quantum computer and quantum analog computer are described. The artificial molecule consists of two or three coupled quantum dots stacked along z direction and one single electron, In quantum computer, one-qubit and two-qubit gates are constructed by one molecule and two molecules, respectively. The coupling between two qubits in a quantum gate can be controlled by thin film electrodes. We also constructed a quantum analog computer by designing a three-dot molecule network and mapping a graph 3-colorability problem onto the network. The ground-state configuration of the single electrons in the network corresponds to one of the problem solutions, We numerically study the operations of the two kinds of the quantum computers and demonstrate that they quantum gates can perform the quantum computation and solve complex problems.

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In this paper a new half-flash architecture for high speed video ADC is presented. Based on a high speed single-way analog switch circuit, this architecture effectively reduces the number of elements. At the same lime no sacrifice of speed is needed compared with the normal half-flash structure.

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禾谷孢囊线虫严重影响禾谷类作物的产量,在小麦中由禾谷孢囊线虫引起的产量损失可达30-100%。尤其在澳大利亚、欧洲、印度和中东危害严重,目前禾谷孢囊线虫已成为危害我国作物的主要病源。控制禾谷孢囊线虫的方法主要有:作物轮作、杀线虫剂、寄主抗性等等,其中基因工程方法培育抗线虫小麦品种被认为是最经济有效的方法。分离抗禾谷类孢囊线虫基因对揭示抗性基因结构与功能及其表达调控具有重要意义。 尽管小麦是重要的粮食作物,在小麦中已发现的抗禾谷孢囊线虫的基因很少,而比其近缘属如节节麦、易变山羊草、偏凸山羊草中含有丰富的抗源。目前已鉴定出禾谷孢囊线虫抗性位点Cre,并发现了9个禾谷孢囊线虫抗性基因(Cre1,2, 3, 4, 5, 6, 7, 8, and R) ,其中只有Cre1和Cre8直接从普通小麦中获得。从节节麦中获得的Cre3基因能最有效的控制线虫数量,其次是Cre1和Cre8。这些基因的克隆对于了解禾谷孢囊线虫抗性机制及进一步的育种应用都是非常关键的。然而,目前为止仅有Cre3基因通过图位克隆的方法从节节麦中被分离得到。该基因已被克隆得到的多数线虫抗性基因一样均属于核苷酸结合位点区(NBS)-亮氨酸重复序列区(LRR)基因家族。目前,已有很多抗性基因被分离,这些已知的NBS-LRR类抗性基因的保守序列为应用PCR的方法克隆新的抗性基因提供了可能。 因此本课题的目的是采用保守区同源克隆、3′RACE 和5′RACE 等方法从抗禾谷孢囊线虫小麦-易变山羊草小片段易位系E10 中克隆小麦抗禾谷孢囊线虫基因全序列,进而通过半定量PCR 和荧光定量PCR 研究该基因的表达模式。同时通过mRNA 差别显示技术和任意引物PCR(RAP-PCR)技术分离克隆植物禾谷孢囊线虫抗性基因及其相关基因,为阐明植物抗病性分子机制以及改良作物抗病性和作物育种提供基础,为通过分子标记辅助育种和基因工程方法实现高效、定向转移抗病基因到优良小麦品种奠定了重要的理论和物质基础。主要研究结果: 1. 本实验根据此前从抗禾谷孢囊线虫材料E-10 扩增得到的与来自节节麦的抗禾谷孢囊线虫Cre3 基因及其他的NBS-LRR 类抗性基因的NBS 和LRR 保守区序列设计了两对特异性引物,从E10 中扩增到532bp 和1175bp 的两个目标条带,它们有一个32bp 的共同序列,连接构成总长为1675bp 的NBS-LRR 编码区(命名为RCCN)。根据RCCN设计引物,利用NBS-LRR区序列设计引物,通过5′RACE 和3′RACE 技术采用3′-Full RACE Core Set(TaKaRa)和5'-Full RACE Kit (TaKaRa)试剂盒,反转录后通过嵌套引物GSP1 和GSP2 分别进行两轮基因特异性扩增,分别将NBS_LRR 区向5′端和3′端延伸了1173bp 和449bp,并包含了起始密码子和终止密码子。根据拼接的得到的序列重新设计引物扩增进行全基因扩增的结果与上面获得的一致。拼接后得到全长2775 bp 的基因序列(记作CreZ, GenBank 号:EU327996)。CreZ 基因包括完整的开放阅读框,全长2775 bp,编码924个氨基酸。序列分析表明它与已知的禾谷孢囊线虫抗性基因Cre3的一致性很高,并且它与已经报到的NBS-LRR 类疾病抗性基因有着相同的保守结构域。推测CreZ基因可能是一个新的NBS-LRR 类禾谷孢囊线虫抗性基因,该基因的获得为通过基因工程途径培育抗禾谷孢囊线虫小麦新品种奠定了基础,并为抗禾谷孢囊线虫基因的调控表达研究提供了参考。 2. 通过半定量PCR和SYBR Green荧光定量PCR技术对CreZ基因的相对表达模式进行了研究。以α-tubulin 2作为参照,采用半定量PCR 分析CreZ 基因在不同接种时期1d, 5d, 10, 15d 的E-10的根和叶的的表达情况。在内参扩增一致的条件下,CreZ 在E-10的根部随着侵染时间的增加表达量有明显的增加,在没有侵染的E-10的根部其表达量没有明显变化,而在叶中没有检测表达,说明该基因只在抗性材料的根部表达。SYBR Green定量PCR分析接种前后E10根部基因CreZ基因的表达水平为检测CreZ基因的表达建立了一套灵敏、可靠的SYBRGreen I 荧光定量PCR 检测方法。接种禾谷孢囊线虫后E10根内CreZ基因的相对表达水平显著高于接种前。随接种时间的延长持续增加,最终CreZ基因的相对表达量达到未接种的对照植株的10.95倍。小麦禾谷孢囊线虫抗性基因CreZ的表达量与胁迫呈正相关,表明其与小麦的的禾谷孢囊线虫抗性密切相关,推测CreZ基因可能是一个新的禾谷孢囊线虫候选抗性基因。 3. 针对小麦基因组庞大、重复序列较多,禾谷孢囊线虫抗性基因及其相关基因的片断难以有效克隆的问题,通过mRNA 差别显示技术及RAP-PCR 技术分离克隆植物禾谷孢囊线虫抗性及其相关基因。试验最终得到154 条差异表达条带,将回收得到的差异条带的二次PCR 扩增产物经纯化后点到带正电的尼龙膜上,进行反向Northern 杂交筛选,最终筛选得到102 个阳性差异点。将其中81 个进行测序,并将序列提交到Genbank 中的dbEST 数据库,分别获得登录号(FE192210 -FE192265,FE193048- FE193074 )。序列比对分析发现,其中26 个序列与已知功能的基因序列同源;有28 条EST 序列在已有核酸数据库中未找到同源已知基因和EST,属新的ESTs 序列;另外27 个EST 序列与已知核酸数据库中的ESTs 具有一定相似性,但功能未知。其所得ESTs 序列补充了Genbank ESTs 数据库,为今后进一步开展抗禾谷类孢囊线虫基因研究工作打下了基础。结合本试验功能基因的相关信息,对小麦接种禾谷孢囊线虫后产生的抗性机制进行了探讨。接种禾谷孢囊线虫后植物在mRNA 水平上的应答是相当复杂的,同时植物的抗病机制是一个复杂的过程,涉及到多个代谢途径的相互作用。 The cereal cyst nematode (CCN), Heterodera avenae Woll, causes severe yieldreductions in cereal crops. The losses caused by CCN can be up to 30-100% in somewheat fields. At present, cereal cyst nematode has become the major disease sourcein China and it also damaged heavily in Australia, Europe, India and Middle East.The damage caused by CCN can be mitigated through several methods, includingcrop rotation, nematicide application, cultural practice, host resistance, and others.Of these methods, incorporating resistance genes into wheat cultivars and breedingresistant lines is considered to be the most cost-effective control measure forreducing nematode populations. Although wheat is an economically important crop around the world, far fewergenes resistant to CCN were found in wheat than were detected in its relatives, suchas Aegilops taucchi, Aegilops variabilis and Aegilops ventricosa. Cloning these genesis essential for understanding the mechanism of this resistance and for furtherapplication in breeding. Because of the huge genome and high repeat sequencescontent, the efficient methods to clone genes from cereal crops, are still lacking. A resistance locus, Cre, has been identified and 9 genes resistant to CCN (designatedCre1, 2, 3, 4, 5, 6, 7, 8, and R) have been described, in which Cre1 and Cre8 werederived directly from common wheat. The Cre3 locus, which was derived from Ae.tauschii, has the greatest impact on reducing the number of female cysts, followed byCre1 and Cre8. Cloning these genes is essential for understanding the mechanism ofthis resistance and for further application in breeding. However, to this point, only Cre3, a NBS-LRR disease resistance gene, has been obtained through mappingcloning in Ae. tauschii. The majority of nematode resistance genes cloned so far belong to a super familywhich contains highly conserved nucleotide-binding sites (NBS) and leucine-richrepeat (LRR) domains. To date, many NBS-LRR resistance genes have been isolated.The conserved sequences of these recognized NBS-LRR resistance genes provide thepossibility to isolate novel resistance genes using a PCR-based strategy. The aim of the present study was to clone the resistance gene of CCN fromWheat/Aegilops variabilis small fragment chromosome translocation line E10 whichis resistant to CCN and investigate the espression profiles of this gene withsemi-quantitative PCR and real-time PCR. Another purpose of this study is cloningthe relational resistance gene for CCN by mRNA differential display PCR andRAP-PCR. These works will offer a foundation for disease defence of crop andbreeding and directional transferring resistance gene into wheat with geneengineering. Primary results as following: 1.According to the conversed motif of NBS and LRR region of cereal cystnematode resistance gene Cre3 from wild wheat (Triticum tauschlii) and the knownNBS-LRR group resistance genes, we designed two pairs of specific primers for NBSand LRR region respectively. One band of approximately 530bp was amplified usingthe specific primers for conversed NBS region and one band of approximately 1175bpwas amplified with the specific primers for conversed LRR region. After sequencing,we found that these two sequences included 32bp common nucleotide having 1675bpin total, which was registered as RCCN in the Genbank. Based on the conservedregions of known resistance genes, a NBS-LRR type CCN resistance gene analog wasisolated from the CCN resistant line E-10 of the wheat near isogenic lines (NILs), by5′RACE and 3′ RACE.designated as CreZ (GenBank accession number: EU327996) .It contained a comlete ORF of 2775 bp and encoded 924 amino acids. Sequencecomparison indicated that it shared 92% nucleotide and 87% amino acid identitieswith those of the known CCN-resistance gene Cre3 and it had the same characteristic of the conserved motifs as other established NBS-LRR disease resistance genes. 2. Usingα-tubulin 2 as exoteric reference, semi-quantitative PCR and real-timePCR analysis were conducted. The expression profiling of CreZ indicated that it wasspecifically expressed in the roots of resistant plants and its relative expression levelincreased sharply when the plants were inoculated with cereal cyst nematodes. therelative expression level of the 15days-infected E10 is the 10.95 times as that ofuninfected E10,ultimately. It was inferred that the CreZ gene be a novel potentialresistance gene to CCN. 3.We cloned the relational resistance gene for CCN by mRNA differentialdisplay PCR and arbitrarily primed PCR fingerprinting of RNA from wheat whichpossess huge and high repeat sequence content genomes. Total 154 differentialexpression bands were separated and second amplified by PCR. The products werenylon membrane. The 102 positive clones were filtrated by reverse northern dot blotand 81 of those were sent to sequence. The EST sequences were submitted toGenbank (Genbank accession: FE192210 - FE192265, FE193048 - FE193074). Thesequences alignment analysis indicated 26 of them were identical with known genes;28 were not found identical sequence in nucleic acid database; another 27 ests wereidentical with some known ests, but their functions were not clear. These ESTsenriched Genbank ESTs database and offered foundation for further research ofresistance gene of CCN.

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目的 探讨颅颌运动仿真系统的骀接触模拟精度,为该仿真系统的应用提供依据.方法 制作10副石膏模型并上(牙合)架.用(牙合)架模拟侧方运动,三维扫描侧方运动终点(牙合)架上的上下颌模型,重建数字化上下颌模型作为对照组.运用仿真系统模拟耠架的侧方运动,以仿真系统输出的侧方运动终点的数字化上下颌模型为试验组.通过比较试验组与对照组下颌牙列之间的位置差异评价仿真系统的(牙合)接触模拟精度.结果 仿真系统模拟的下颌牙列与对照组下颌牙列之间的绝对平均距离为(0.18±0.05)mm;在前后左右四个分区中,两组右后牙区之间的绝对平均距离最大,为(0.19±0.07)mm.结论 该仿真系统的体外胎接触模拟精度为0.19mm.

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Water is an integral part of DNA, and the conserved water molecules at the binding sites can modulate drug binding to DNA or protein. We report here that anthracycline antitumor antibiotics, adriamycin (AM) and daunomycin (DM), binding to DNA is accompanied by different hydration changes, with AM binding resulting in the uptake of about twice as many water molecules as DM. These results indicate that water is playing an important role in drug binding to DNA.

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The synthesis, thermal and emission properties of an electrophosphorescent platinum(II) metallopolyyne polymer consisting of 9-butylcarbazole-2,7-diyl spacer P1 are described. The optical and electronic properties of P1 are compared to their molecular diplatinum(II) and digold(I) model complexes. The photophysical properties of P1 are somehow analogous to its 2,7-fluorene-linked congener but differs significantly from that for the 3,6-carbazole derivative. Its optical band gap is notably reduced as compared to that for the 3,6-carbazole analog. Multi-layer polymer light-emitting diodes (PLEDs) were fabricated with P1 as the emitting layer which gave a strong green-yellow electrophosphorescence. The best PLED can reach the maximum current efficiency of 4.7 cd . A(-1) at 5 wt.-% doping level, corresponding to an external quantum efficiency of 1.5%. This represents the first literature example of efficient PLEDs exhibiting pure triplet emission under electrical excitation for metallopolyynes without the concomitant singlet emission.

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A new fluorinated diamine monomer, [1,4-bis(4-amino-3-trifluoromethylphenoxy)benzene (2)], and a known isomeric analog 1,4-bis(4-amino-2-trifluoromethylphenoxy)benzene (3) were synthesized. A series of organosoluble polyimides Ia-d and IIa were prepared from the diamines (2, 3) and dianhydrides (a-d) by a high-temperature one-step method. The effects of the trifluoromethyl substituents on the properties of polyimides were evaluated through the study of their soluble, thermal, optical, and gas permeability properties. Polyimides (Ia-d) had glass transition temperatures between 229 and 279 degrees C, and the temperatures at 5% weight loss ranged from 510 to 533 degrees C under nitrogen. These polyimides could be cast into flexible and tough membranes from DMAc solutions. The membranes had tensile strengths in the range of 137-169 MPa, tensile modulus in the range of 1.6-2.2 GPa and elongations at break from 11% to 14%. The polyimide la with trifluoromethyl groups ortho to the imide nitrogen exhibited enhanced gas permeability, solubility, transparency, and thermal stability compared with the isomeric polyimide IIa with the CF3 group meta to the imide nitrogen.

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The thiol group of glutathione (GSH) reacts specifically with 2,4-di-ni-trochlorobenzene to give S-substituted dinitrophenyl glutathione (GSH-S-DNP); two carboxyl groups of GSH-S-DNP were further esterified by n-butanol to produce the hapten, multisubstrate analog GSH-S-DNP Butyl Ester (GSH-S-DNP BE). The primary structure of the hapten was characterized by the free. amino group analysis, H-1 NMR, IR determinations and the elemental analysis. The hapten was then conjugated to bovine serum albumin (BSA) in the presence of glutaraldehyde. The reaction mixture was purified by Ultrogel AcA54 colum chromatography to give the antigen. On an average, 25 haptens were bound to each BSA molecule. Electrophoresis analysis showed that the average molecular weight of the antigen was 87 KD. CD spectrum showed that the a-helix content of the antigen increased.

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Planktonic foraminiferal faunas, oxygen isotope and modern analog technique sea surface temperature records were obtained in piston core DGKS9603 (28degrees08.869'N, 127degrees16.238'E, water depth 1100 in) collected from the middle Okinawa Trough. During the last glaciation, four cold events were identified and correlate Heinrich events (HE) H2-5 of the last 45 ka. During the last deglaciation, core DGKS9603 has begun to be influenced by the Kuroshio since about 16 cal ka BP. Three weakenings of this warm current occurred at about 2.8-5.3, 11.4 and 15.5 cal ka BP respectively. Among the three fluctuations, the oldest one is synchronous with HE1 and could be a response to the strong cooling observed in the North Atlantic Ocean. The fluctuation occurring at about 11.4 cal ka ago corresponds to the Younger Dryas within the age error bars. Our observations provide new evidence that the HEs documented from Greenland and the northern North Atlantic had a global climatic impact. Changes in the intensity of the East Asian monsoon could be the main mechanism responsible for the paleoccanographic variations observed in the Okinawa Trough. (C) 2001 Elsevier Science B.V. All rights reserved.

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提出了一种多回路测控系统的设计方案。该方案仅使用一个DSP(数字信号处理器)及一个多通道集成的D/A转换器件MAX5307,不仅同时保证了多个测控回路的实时性及控制精度,而且实现简单,成本低廉。文中结合实际系统,给出了其具体的硬件和软件实现。该方法具有广泛的适用性,对类似系统的设计具有参考价值。

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介绍了一种基于嵌入式ARM9技术的微型ROV的控制装置及控制方法。该装置可以同时进行两通道串行通讯,实现微型ROV的视频信号、潜水深度、艏向角度、纵倾角度、横摇角度、电子舱温度等数据的采集和与上位机的通讯传输;该装置可以采集16路模拟量信号和12路数字量信号,输出4路模拟量信号和12路TTL电平信号,实现推进器、水下灯、水下摄像机、云台等ROV功能器件的驱动。该装置具有通讯能力强、集成度高、功耗低等特点,可以满足微型ROV所有的常用功能要求。

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本文介绍了一种利用 PWM方式进行模拟量长线传送的应用,突出了它的结构简单、抗干扰能力强的优点。

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目的利用单片机技术设计多路温度测控系统,实现多路温度的测量和控制.方法系统以单片机AT89C52为核心,利用多路转换器和新型数字器件MAX6675构成8路K型热电偶温度测量电路,利用D/A转换器AD7528和驱动电路构成输出电路,实现8路一一对应的闭环温度测量控制.系统软件采用PID控制器.结果实践证明,可根据需要增减系统温度信号采样通道的数目,使用软件抗干扰措施,提高了采样数据的可靠性.简化了输入输出硬件结构,使系统具有低成本高速度和较好的测量控制精度.结论多路温度测控系统作为整机适用于现场测量控制应用,也可作为多路温度控制模块应用在体积小、温度测量精度要求较高的大型系统中.

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The loess-paleosol sequences in China are among the best continental records of paleoclimate changes. Although numerous sedimentological and geochemical studies have contributed greatly to the understanding of past climate changes during this period, it is still necessary to decipher more details through investigating these sequences using various approaches including biological analyses. In this study, we analyze the mollusk fossil assemblages preserved in the upper part of the Xifeng section, from the fifth loess layer (L5) to the Holocene soil (S0), with the sampling interval of 10 cm. The main results and conclusions obtained are as follows: 1. A continuous terrestrial mollusk fossil record, covering the past 500 ka, has been obtained from the Xifeng loess-paleosol sequence, which provides important biological data for the study of paleoenvironmental changes in the Loess Plateau and its comparison with marine record during this period. A total of 475 mollusk assemblages were studied, and twenty-one species have been identified among the 210,000 mollusk individuals counted. Among these species, most have modern representatives and are found in previous terrestrial mollusk studies of Chinese loess-paleosol sequences. Thus, they can be grouped into cold-aridiphilous, thermo-humidiphilous, oriental, and cool-humidiphilous ecological groups, as defined by previous studies. 2. Comparison of mollusk assemblages between the last five glacials and four interglacials and Holocene shows very different climate conditions. The warmest period occurred at MIS 11, MIS 5e, and Holocene, respectively. The coldest period is the Last Glacial Maximam, rather than the MIS 12. 3. Our mollusk record provides insight into the climate conditions in the Loess Plateau during the MIS 11, interpreted as the closest analog to the present interglacial. S4 paleosol, equivalent of MIS 11, developed under two major different climate regimes: ranging from the very warm–humid early phase to the mild-cool late interval. Furthermore, a cooling spell has been documented at the interglacial optimum, reflecting unstable climate conditions. The early warm–humid conditions lasted over 30 ka, supporting that MIS 11 is a unique long interglacial in the Quaternary climate history. 4. Comparison of MIS 11 and Holocene climates based on the mollusk species compositions indicates major differences. The climate at the early part of MIS 11 was warmer and more humid than during the Holocene optimum period, but the conditions during the late part of MIS 11 were similar to or cooler than late Holocene. Our study indicates that the extent of warming during the Holocene might be significantly less than the conditions that prevailed during the early part of MIS 11 interglacial period. 5. Two strong summer monsoon events were observed during the MIS 12 and MIS 10. They correspond to the maximam values of insolation gradient between low and high latitudes, suggesting a causal linkage. 6. Our study, combined with the previously investigated Luochuan land snail record, reveals that the climate in the Loess Plateau during MIS 3 experienced three stages: relatively warm, humid climate prevailed during MIS 3c, relatively cold, dry climate during MIS 3b, and relatively warm-humid period during MIS 3a. Climate at this time fluctuated frequently in Luochuan, and changed from warm-cool to cold-dry in Xifeng. Our results reveal that the relatively warm-humid climate during MIS 3c may be resulted from an increasing insolation gradient controlled by obliquity. Our result also reveals that obvious regional difference existed in the Loess Plateau during MIS 3. A greater climate gradient occurred during this time compared with today’s climate pattern in the Loess Plateau.

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The seismic data acquisition system is the most important equipment for seismic prospecting. The geophysicists have been paying high attention to the specification of the equipment used in seismic prospecting. Its specification and performance are of great concerned to acquire precisely and accurately seismic data, which show us stratum frame. But, by this time, limited by the technology, most of the Broad-band Seismic Recorder (BSR) for lithosphere research of our country were bought from fremdness which were very costliness and maintained discommodiously. So it is very important to study the seismic data acquisition system.The subject of the thesis is the research of the BSR, several items were included, such as: seismic data digitizer and its condition monitor design.In the first chapter, the author explained the significance of the implement of BSR, expatiated the requirement to the device and introduced the actuality of the BSR in our country.In the second chapter, the collectivity architecture of the BSR system was illustrated. Whereafter, the collectivity target and guideline of the performance of the system design were introduced. The difficulty of the system design and some key technology were analyzed, such as the Electro Magnetic Compatibility (EMC), system reliability technology and so on.In the third chapter, some design details of BSR were introduced. In the recorder, the former analog to digital converter (ADC) was separated from the later data transition module. According to the characteristic of seismic data acquisition system, a set high-resolution 24-bit ADC chip was chosen to the recorder design scheme. As the following part, the noise performance of the seismic data channel was analyzed.In the fourth chapter, the embedded software design of each board and the software design of the workstation were introduced. At the same time the communication protocol of the each module was recommendedAt the last part of this thesis, the advantages and the practicability of the BSR system design were summarized, and the next development items were suggested.