549 resultados para Panda (Schooner)


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A closed-loop control technique based on monitoring phase current risetime for switched reluctance (SR) motors without direct rotor-position sensors has been studied and implemented successfully. In this technique the variation in incremental phase inductance in a SR motor is used to detect rotor position. A control circuit for current-waveform-based rotor position detection has been implemented using hard-wire digital circuits. Torque-speed and system-efficiency characteristics resulting from the application of the method to a 4-kW, four-phase SR motor with an IGBT drive are presented.

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保护区是否真的能起保护作用?保护区究竟如何布局?这是自然保护区的建设一直争论不休的课题。就大熊猫保护而言,目前面临的最紧迫问题可能不是保护区数量多少的问题,而是这些多个保护区组成的保护区群的配置或格局是否合理。因此,本研究以岷山大熊猫保护区群为研究对象,分析现有大熊猫及栖息地及其保护现状,指出目前保护区存在的问题,并对岷山大熊猫自然保护区群合理布局提出建议性设计,以期为大熊猫保护及自然保护区建设的理论提供借鉴。 到目前,为了保护大熊猫,在岷山地区已经建立了1 7个自然保护区,这些保护区的建立对大熊猫的保护起到了非常重要的重要。但是,大熊猫栖息地仍然持续下降。就其原因有两方面,即岷山地区人为活动的干扰,如旅游业的盲目发展。但,同时大熊猫自然保护区本身的布局存在一定的不合理性。最后,从景观尺度上提出岷山大熊猫保护区群合理建设的布局,即在分析现有保护布局基础上,找到优先保护的敏感地带建立廊道,将所有保护区连成布局合理的保护区群。 大熊猫受威胁的关键因子并不是竹子,而是森林.竹子复合系统的破碎化或质量的退化,故保护大熊猫应从保护森林、恢复森林.竹子复合生态系统的质量入手。但是,具体实践中究竞采取什么模式来恢复退化的大熊猫栖息地?选取不同模式的科学依据是什么?如何评判不同恢复模式的成本和效益?这些方面的工作到目前缺少系统研究。本研究在分析了岷山地区自然、社会与经济条件的基础上,从荒山荒地造林、天然林保护与低效林地改造主要植被恢复措施着手,全面分析各类植被恢复措施所形成植被的生态效益(保持水土、涵养水源、保持肥力等)、经济收益(木材、果品和林副特产品)、社会效益(种植结构、劳动力再分配等),总结出植被恢复成本和效益的构成要素,计算主要植被恢复模式的成本和效益,为选择适宜的植被恢复措施、典型植被恢复模式和合理确定植被恢复技术提供科学依据,从而推动岷山植被快速健康地恢复,为大熊猫提供适宜的生存空间。 三峡大坝的建设使其固有水域的人为改造导致水位上升,使原本连续的山地生态系统被分割成大小不等的岛屿。水位变化导致的这种生境岛屿化为栖息地破碎化和岛屿生物地理学提供了十分难得的实证研究的机会。然而,同时,这种栖息地的片段化无疑对三峡库区生物多样性保护和生态系统的完整性造成威胁。到目前,为了监测库区建设对生态环境的影响,已经建立了22个定位观测站,但没有一个是生境破碎化方面的,为此建议尽快建立生境破碎化方面的定位研究站。三峡库区生物多样性丰富,但保护区面积仅仅占库区面积的6.9%,而同期我国已经建立了1 999个自然保护区,占国土面积的15%,因此,非常迫切建立更多的保护区(至少达到全国平均水平)。为了从宏观尺度上加强对库区的综合保护,建议从景观生态学的角度出发,将库区作为一个自然、社会和经济复合生态系绕对待。

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The monophyletic group Caniformia in the order Carnivora currently comprises seven families whose relationships remain contentious. The phylogenetic positions of the two panda species within the Caniformia have also been evolutionary puzzles over the past

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Developments in Micro-Electro-Mechanical Systems (MEMS), wireless communication systems and ad-hoc networking have created new dimensions to improve asset management not only during the operational phase but throughout an asset's lifecycle based on using improved quality of information obtained with respect to two key aspects of an asset: its location and condition. In this paper, we present our experience as well as lessons learnt from building a prototype condition monitoring platform to demonstrate and to evaluate the use of COTS wireless sensor networks to develop a prototype condition monitoring platform with the aim of improving asset management by providing accurate and real-time information. © 2010 IEEE.

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自然界丰富的生物多样性不断地激发着包括达尔文在内所有生物学家的研 究热情。自从达尔文进化论提出以来,进化生物学所要回答的一个基本问题就 是生物是如何从一个共同祖先进化到如此丰富多样的。随着分子生物学中心法 则的发现和基因组时代的到来,比较不同物种的基因组(即通过进化基因组学 研究)找出进化过程中发生的遗传变异成为求解这一基本进化生物学问题的重 要方法。 通过比较不同物种的基因组可以发现新基因的诞生是在进化过程中普遍存 在的基本过程,对生物的进化发挥着重要的作用。大量前人的研究认为新基因 主要通过老基因的重复产生,新基因的从头起源很少发生或根本不存在。直至 最近在果蝇中发现了新基因从头起源事件才改变了人们的这种看法,然而这些 研究缺少功能的证据。我们通过比较酿酒酵母近缘种的基因组序列发现了酿酒 酵母中进化出的一个从头起源的新基因BSC4,并且提供了群体遗传学、转录 组、蛋白质组学和表型水平的证据支持这个基因的生物学功能和蛋白编码能 力。同时我们在其近缘种中发现其直系同源的非编码序列拥有RNA 水平的表达 活性,由此我们提出了一个蛋白基因从头起源的两步模型。我们认为一个非编 码DNA 序列进化为蛋白编码基因需要经历两个步骤:第一,DNA 序列先进化出 顺式元件来招募转录机器变成有RNA 转录活性的序列;第二,转录的序列通过 突变获得开放读码框并加入到翻译机器中。 进一步的分析提示BSC4 可能在酿 酒酵母转换到营养贫瘠的环境中并进入生长停滞期时对酿酒酵母的适应性作出 了贡献。酿酒酵母是一种对人类生活十分重要的微生物,它进行发酵的能力在 工业生产中具有重要应用价值。生长停滞期是酿酒酵母实际生产应用中频繁经 ii 历的过程,对这一阶段的适应性进化也对其工业应用有重要意义。 大熊猫是我国的国宝。它是一种具有独特特性的熊科动物,进化上属于食 肉目类群,食性确以竹子为主。为了适应其食性,其前掌的籽骨还发育出了著 名的“伪拇指”来帮助其进食。然而这些性状是如何进化出来的确一直是个未 解之谜。进化基因组学为解决这些问题提供了一个重要的思路和方法。我们通 过应用第二代测序技术对大熊猫基因组进行了从头测序和组装,通过和其它基 因组比较分析发现了大熊猫基因组中不存在编码降解纤维素酶的基因,提示了 大熊猫特殊食性的进化机制很可能是通过其肠道微生物的改变而发生的。同 时,我们也发现了大熊猫鲜味受体的退化,这很可能是一个伴随其食性进化而 发生的变异。 长雄野生稻是栽培稻的近缘种,它和栽培稻同属于AA 基因组。由于它具有 以发达的地下茎为生理表型的多年生特性和自交不亲和性,研究这些特性背后 的遗传机制对改良栽培稻一年生为多年生和构建自交不亲和的新杂交稻育种体 系有重要意义。我们从头测序并组装了长雄野生稻的基因组,通过和栽培稻基 因组的比较分析,在前人工作的基础上找出了决定上述两个重要性状的可能的 基因组区域,为进一步的实验验证提供了候选的基因。同时我们的序列提供了 对其它野生稻特性研究的重要基础。

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We analyze theoretically the polarization characteristics of polarization maintaining fiber and study the basic measurement principles of beat length and polarization extinction ratio of this kind of optical fiber. According, to the dependence of the phase difference between two orthogonally polarized modes (denoted Os HE(11)(x) and HE(11)(y)) transmitted in the polarization maintaining fiber on the light wavelength, we propose the wavelength-sweeping modulation method to measure the beat length and the model birefringence. Based on this technique, the hew length and polarization extinction ratio of the PANDA polarization maintaining fibers (PMFs) (provided by Yangtze Optical Fiber and Cable Company, Wuhan, China) were investigated in detail. Experimental results show good consistent with the theoretical ones. We find that this method shows high measurement precision with the advantages of clear measurement principle and easy to operate. 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1466-1469, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25244

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大熊猫(Ailuropoda melanoleuca)是我国特有的珍稀濒危物种,国家Ⅰ级重点保护野生动物,被称为“国宝”。目前,大熊猫被局限在我国中西部的岷山、邛崃、大相岭、小相岭、凉山和秦岭6大山系中。对大熊猫的保护和研究,我国政府、保护生物学科研人员、社会各界及国际保护组织都做了大量的工作。根据全国三次大熊猫调查结果显示,大熊猫栖息地片段化现象依然存在,形成多个隔离的大熊猫小种群。尤其在小相岭、大相岭、岷山B和岷山C种群,大熊猫数量较少,且栖息地破碎,面临较大威胁。有的山系大熊猫种群数量些已低于最小可存活大熊猫种群的数量,如果不采取人工措施,这些种群的大熊猫存在灭绝的危险。 将圈养大熊猫放归野外,以补充野外大熊猫种群数量,增加其遗传多样性,复壮和扩大野生大熊猫种群,是大熊猫人工繁育的最终目标。为降低放归的风险性,在放归人工繁育大熊猫前,将救护存活的野生大熊猫先有计划放归野外,并对其进行跟踪监测,对积累大熊猫放归经验,进一步研究大熊猫野外生物学习性,丰富放归地大熊猫种群遗传多样性,为人工繁育大熊猫放归野外夯实基础,具有十分重要的意义。2005年8月8日,国家林业局和四川省人民政府联合将救护野生大熊猫“盛林1号”放归于龙溪-虹口国家级自然保护区内岷山B大熊猫种群栖息地,并进行系统监测研究。成功的积累了一些放归经验和放归大熊猫的生物学资料,为人工繁育大熊猫的放归奠定了一定基础。 2005年8月至2007年6月期间,我们采用GPS无线电项圈、粪便DNA检测和红外线自动触发相机陷阱的方法,对大熊猫“盛林1号”进行了追踪监测,获得了以下成果: 1.通过分析“盛林1号”放归后了活动趋势和采用两种贝叶斯方法,利用目前五大山系的已有微卫星遗传数据,检测“盛林1号”与五大山系的遗传关系的远近,推测其来源于邛崃山系的可能性较大。 2.收集了大量“盛林1号”野外生境选择数据。我们认为“盛林1号”放归后经历了应急期、初步稳定期、长途迁徙期三个阶段(这可能是今后放归大熊猫都必经的三个时期),并与当地大熊猫种群已发生交流。目前“盛林1号”仍在寻找适合的巢域。 3.结合过去监测数据分析,在放归区域大熊猫和羚牛尽管同域分布,但由于食性不同,对微生境选择还是有着很大差异,因此保护管理对策要有针对性。 4.“盛林1号”的放归是成功的。救护大熊猫异地放归工作应继续开展,但要改进放归后的监测技术。要改进现有对人工饲养大熊猫野化培训方法和放归方式,才能真正将人工繁殖个体放归野外。 Giant Panda (Ailuropoda melanoleuca) is an endangered species endemic to China. It was listed as National Protected I Class Species and is crowned as “National treasure” of China. The populations of Giant Panda are limited in 6 mountain system in Center-West of China, i.e. Mingshan, Mt. Qionglai, Mt. Daxiangling,Mt. Xiaoxiangling, Mt. Liangshan and Mt. Qinling. The results of the Third National Survey on Giant Panda showed that the habitats of Giant Panda is still fracted and Giant Panda population is divided into several isolated small populations. Population B from Mt. Daxiangling, Mt. Xiaoxiangling and Mt. Mingshan and Population C from Mt. Mingshan are very small with very fracted habitat and are more endangered. Several populations in those mountain systems are smaller than Minimum Viable Population of Giant Panda. It is very possible that those populations will be extinct without artificial help. The ultimate Goal of Reintroduction caged Giant Panda to wild is to increase wild population size and genetics diversity and rebuild and expand wild Giant Panda population. It is of significant to return rescued wild Giant Panda to wild and monitor their behavior before reintroduction artificial reproduced Giant Panda. It will increase our knowledge on reintroduction of Giant Panda. Aug 8th, 2005, “Shenglin 1”, a rescued wild Giant Panda was returned to Longxi-Hongkou National Nature Reservoir, which is habitat of Giant Panda Population B of Mt. Mingshan. A systematic monitor was carried out on “Shenglin 1”, and the successful return enriched our biological knowledge on Giant Panda reintroduction. It will be very help for future conservation work on reintroduce artificial reproduced Giant Panda. “Shenglin 1” was tracked with GPS collar, DNA in feces and infrared-trigged camera from Aug 2005 to Jun 2007. 1. Locomotion behavior and microsatellites comparison with Giant Panda from the 5 mountain systems indicated that “Shenglin 1” is possibly from Mt. Qionglai. 2. Habitat usage of “Shenglin 1” was studied. It was suggested that there were 3 phases after return, i.e. emergency response, preliminary stable phase and long distance locomotion, which could be a general process for other returned Giant Panda. It was indicated that there was some interaction between “Shenglin 1” and local population. “Shenglin 1” is seeking for suitable home range now. 3. Monitor data also indicated that microhabitat preference of Giant Panda and takin (Budorcas taxicolor) are different because of different diet, though they are sympatric. It was suggested that conservation management for the two species should be plan in particular. 4. The reintroduction of “Shenglin 1” is a successful case. The program of return rescued Giant Panda to other habitats is of value and should be continued. However, more improvement is needed for the monitor technique. More improvement is need for feralization and returning before we return artificial reproduced Giant Panda to wild.

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大熊猫(Ailuropoda melanoleuca)是我国特有的濒危野生动物之一,迁地保护已经成为大熊猫物种保护的一个重要方面。当前大熊猫圈养种群数量增长很快,但是其“多雄配一雌”的交配(配种方式),以及生产过程中记录遗失等原因,造成圈养种群普遍存在亲子关系不清、谱系混乱等问题。为了加强遗传管理,有必要进行亲子关系鉴定、完善谱系;还需要检测种群的基因多样性水平,并在此基础上提出相应的遗传管理建议。 本研究应用9个具有高度多态性的大熊猫微卫星标记,对来自成都大熊猫繁育研究基地2006和2007年度出生的17只大熊猫幼崽及其全部候选父母共37个样品做了基因型分析;然后应用最大似然法,判断幼崽的父-子关系。同时,还对来自卧龙大熊猫保护研究中心的31只大熊猫个体也做了基因分型。将两个种群的数据进行比较:1)等位基因多样性和杂合度水平;2)通过F统计法,分析两个种群的遗传分化水平;3)通过遗传距离法,对所有个体进行聚类分析。 研究结果表明: 1)在母子关系不清的情况下,9个微卫星标记联合的父亲鉴定排除概率E为0.940090;而在母子关系确实的条件下,E= 0.993933。由于本研究中所有后代的母亲都是清楚的,因此这9个微卫星位点能够有效用于圈养大熊猫的亲子鉴定。似然法分析也表明,本研究所获得的亲子鉴定结果置信度在95%以上。 2)2005年种源交换后,成都大熊猫的等位基因多样性和杂合度水平都略高于卧龙种群(但没有达到显著水平),两个种群间的遗传分化水平也有所降低。但是,与卧龙相比,成都种群面临较大的近交压力。 基于以上研究结果,我们建议:进一步加强种源交换和基因交流,把两个种群当作一个遗传单元(MU)来进行管理。 Giant panda (Ailuropoda melanoleuca) is one of the endangerd wildlife endemic to China, and the ex-situ breeding become more and more important for the conservation of this speices. Although the captive population is expanding rapidly, the uncertainty occurs because the paternities of cubs are not clear due to the breeding pattern of “multiple male to single female,”as well as the records lost, resulting in errors in the studbook. For this reason, the paternity of the cubs and the genetic diversity of the captive giant pandas should be tested carefully to get information for the genetic management in the future. 9 polymorphism microsatellite markers were used to do paternity assignment for the 17 cubs born in 2006 and 2007 from Chengdu Research Base for Giant Panda Breeding (CGB) based on the maximum-likelihood methods. A total of 37 individuals were sampled, including all the candidate dams and sires. These samples were also used for comparing with 31 individuals sampling from Wolong China Research and Conservation Center for the Giant Panda (WCG). The comparing indexes were: 1) Allelic diversity and heterozygosity; 2) Genetic differentiation based on F-statistic; 3) Cluster analysis based on genetic distance. The results show that: 1) If the mother is unkown, the combined exclusion probability using these 9 loci is 0.940090. If the mother is known then the exclusion probability is 0.993933. Since the dam-offspring relationship is known in captive populations, the results could resolve unknown paternities in the study. And the confidence level of the results is 95% based on the likelihood methods. 2) The allelic diversity and the heterozygosity of CGB were higher than WCG (n ot significant), and the genetic differentiation was reduced a little since the genetic exchange between two populations in 2005. However, the population of CGB will be threatening by inbreeding seriously than that of WCG. From above, we suggest to reiforce the genetic exchange and geneflow between CGB and WCG, and these two populations should be regarded as one genetic management unit (MU).

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A theoretical study of the (p) over barp -> (p) over barn pi(+) reaction for antiproton beam energy from 1 to 4 GeV is made by including contributions from various known N* and Delta* resonances. It is found that for the beam energy around 1.5 GeV, the contribution of the Roper resonance N-(1440)* produced by the t-channel sigma exchange dominates over all other contributions. Since such a reaction can be studied in the forthcoming PANDA experiment at the GSI Facility of Antiproton and Ion Research (FAIR), the reaction will be realistically the cleanest place for studying the properties of the Roper resonance and the best place for looking for other "missing" N* resonances with large coupling to N sigma.

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在HIRFL-CSR上筹建的兰州强子谱仪(HPLUS)中,前角区径迹探测器(FTD)对于粒子鉴别以及系统的触发都是非常重要的部分之一。计划中的FTD是由五块平面型的多丝漂移室组成,主要用来测量在前角区出射的带电粒子的径迹 (和能损),实现粒子动量测量和粒子鉴别,而联合其它探测器(如TOF和TPC)则可能提高由于取样数限制的粒子鉴别。实现探测器构型的优化和对拟建装置上物理目标的可行性预研是模拟工作的重要目的。快模拟是对拟建装置进行快速优化的有效方法。在Geant4环境对拟建装置的细致模拟,是进一步优化探测器结构、充分的估计探测器整体性能的必要步骤,为将来的谱仪的制造和可能的物理实验提供可靠的参考。 本论文的主要工作包括以下两个方面。(1)在HPLUS概念设计的基础上,发展了局域化的多径迹查找和径迹重建算法,对产物在前角区分布的典型反应道pp→pp+φ(→K+K-)进行了可行性预研,得到FTD对φ的几何覆盖率为83.5%,由于漂移室空间分辨对的动量分辨的贡献为1.3%,并在考虑了本底道pp→pp+K+K-的影响下,重建了φ的不变质量谱,得到φ峰宽度和信噪比分别为1.51MeV和4.36。在考虑到前角区径迹探测器的占有空间和探测要求的情况下对HPLUS构型做出了一定的优化,为全模拟提供了一组FTD参数。(2)基于快模拟得到的参数和参考了PANDA探测器漂移室的情况下,完成了FTD的初步设计并对其中的物质分布进行了预算,通过经验公式得到FTD的空间分辨和多次散射对K+动量分辨的贡献为1.34%和0.34%。在HPLUS模拟平台上,用GDML语言完成了对前角区径迹探测器的构建