Research advances of electrochemical micro/nanofabrication based on confined etchant layer technique

与机械加工相比, 电化学加工技术具有无刀具磨损、无热效应、无机械损伤、加工效率高等优点, 而且适用于柔性、脆性及超硬材料,; 具备传统方法难以实现的复杂结构加工能力, 因而在航空航天、汽车、微电子等领域有着重要应用, 日益成为一种重要的工业制造技术.; 随着超大规模集成电路(ULSI)、微机电系统(MEMS)、微全分析系统(mu-TAS)、现代精密光学系统等高技术产业的迅速发展,; 功能性结构/器件的微型化和集成化的要求越来越高. 由于传统电化学只适用于金属材料, 为了应对微纳制造的时代要求, 拓展电化学加工的材料普适性,; 1992年田昭武院士提出了具有我国自主知识产权的约束刻蚀剂层技术(CELT). 一般的, 约束刻蚀包括3个步骤:; (1)通过电化学、光化学或光电化学的方法在模板电极表面生成刻蚀剂;; (2)通过后续的均相化学反应或自由基衰变反应将刻蚀剂约束在微/纳米厚度的液层内; (3)将模板电极逼近加工基底,; 当约束刻蚀剂层接触被加工基底时, 通过刻蚀反应实现微纳加工. 最近, 联合课题组通过仪器、原理和方法3个方面的努力, 引入外部物理场调制技术,; 实现一维铣削、二维抛光、三维微/纳结构加工, 大幅提升了CELT的技术水平.Compared with mechanical machining, ECM has several advantages, such as; avoiding tool wear, none thermal or mechanical stress on machining; surfaces, as well as high removal rate. Moreover, ECM is capable of; making complex three-dimensional structures and is appropriate for; flexible, fragile, or fissile materials even materials harder than the; machining tool. Thus, ECM has been widely used for various industrial; applications in the fields of aerospace, automobiles, electronics, etc.; ECM methods can be classified usually as electrolytic machining based on; anodic dissolution and electroforming based on cathodic deposition of; metallic materials. Recently, high technology industry, such as; ultralarge scale integration (ULSI) circuits, microelectromechanical; systems (MEMS), miniaturized total analysis systems (mu-TAS) and; precision optics, has developed more and more rapidly, where; miniaturization and integration of functional components are becoming; significant. Nowadays, the feature size of interconnectors in ULSI; circuits has been down to 20 nanometers, predicted by Moore's law.; Confined etchant layer technique (CELT) was proposed in 1992 to; fabricate three-dimensional micro- and nanostructures (3D-MNS) on; different metals and semiconductors, which has been developed an; effective machining method with independent intellectual property; rights. Generally, there are three procedures in CELT: (1) generating; the etchant on the surface of the tool electrode by electrochemical or; photoelectrochemical reactions; (2) confining the etchant in a depleted; layer with a thickness of micro- or nanometer scale; (3) etching process; when the tool electrode is fed to the workpiece, which applicable for 1D; milling, 2D polishing, and 3D microfabrication with an accuracy at micro; or nanometer scale. External physical-field modulations have recently; been introduced into CELT to improve its machining precision. In this; review, the advances of CELT in principles, instruments and applications; will be addressed as well as the prospects.国家自然科学基金; 机械制造系统工程国家重点实验室开放课题资助项

广州南沙滨海泳场II期开发供水源水质研究

为探索南沙滨海泳场II期开发的可行性,对待建泳场周边人工湖、虎门-凫洲水道进行了原位围隔和围隔人工添加外源氮干预的对比试验研究,测定了各水体的8个理化指标和3个生物指标,并对为期6个月的监测数据进行了分析,同时根据地表水环境质量III类标准、按单因子评价法对水体作出水质评价。结果表明:人工湖水为IV类,总磷和化学需氧量(COD)未达标;湖围隔水除COD超标11%外,其他指标均达标;湖围隔加氮水总氮超标率为181%, COD超标率29.5%。水道水为劣V类,总氮浓度均值为2.48 mg·L~(-1),浮游植物生物量随时间变化呈增长趋势,并且以硅藻门藻属居多;水道围隔及围隔加氮水在7、9月以蓝藻为优势类群。与水道水相比,人工湖水更适宜用作泳场的供水源

广州南沙滨海泳场II期开发供水源水质研究

为探索南沙滨海泳场II期开发的可行性,对待建泳场周边人工湖、虎门-凫洲水道进行了原位围隔和围隔人工添加外源氮干预的对比试验研究,测定了各水体的8个理化指标和3个生物指标,并对为期6个月的监测数据进行了分析,同时根据地表水环境质量III类标准、按单因子评价法对水体作出水质评价。结果表明:人工湖水为IV类,总磷和化学需氧量(COD)未达标;湖围隔水除COD超标11%外,其他指标均达标;湖围隔加氮水总氮超标率为181%, COD超标率29.5%。水道水为劣V类,总氮浓度均值为2.48 mg·L~(-1),浮游植物生物量随时间变化呈增长趋势,并且以硅藻门藻属居多;水道围隔及围隔加氮水在7、9月以蓝藻为优势类群。与水道水相比,人工湖水更适宜用作泳场的供水源

广州南沙滨海泳场II期开发供水源水质研究

为探索南沙滨海泳场II期开发的可行性,对待建泳场周边人工湖、虎门-凫洲水道进行了原位围隔和围隔人工添加外源氮干预的对比试验研究,测定了各水体的8个理化指标和3个生物指标,并对为期6个月的监测数据进行了分析,同时根据地表水环境质量III类标准、按单因子评价法对水体作出水质评价。结果表明:人工湖水为IV类,总磷和化学需氧量(COD)未达标;湖围隔水除COD超标11%外,其他指标均达标;湖围隔加氮水总氮超标率为181%, COD超标率29.5%。水道水为劣V类,总氮浓度均值为2.48 mg·L~(-1),浮游植物生物量随时间变化呈增长趋势,并且以硅藻门藻属居多;水道围隔及围隔加氮水在7、9月以蓝藻为优势类群。与水道水相比,人工湖水更适宜用作泳场的供水源

实验测定~(183)0s的Q_(EC)值

用39 MeV-α粒子轰击天然钨靶产生了~(183)Os测量了~(183)Os衰变的γ-β符合谱,确定了β~+能谱的端点能量。最终提取出~(183)Os衰变的Q_(EC)值:Q_(EC)=2.24±0.10 MeV,与系统学的估计值:2.304±0.10MeV在误差范围内相符

安集延鸡mtDNA D-loop遗传多样性及系统进化研究/Research on mtDNA D-loop Genetic Diversity and Phylogeny of Anjiyan Chicken[J]

本研究通过分析mtDNA,对安集延鸡的母系遗传多样性和母系来源进行调查.随机采集了29个安集延鸡DNA样品,测定了D-loop区1 231 bp序列.结果显示,共检测到30个多态位点和10个单倍体型,在859 bp位置发现一个插入/缺失变异,此变异在安集延鸡中的分布频率为51.72％;单倍体型多样度和核苷酸多样度适中,分别为0.776和0.00614;Tajima'D检验和Fu&li'D检验值分别为-0.0041和-0.0192;遗传距离与红色原鸡最近,为0.007;Network结构图显示安集延鸡群体分为五大世系,可划分到家鸡世系的A、B、C、D和E分支中;世系D所占比例最高为45％,据以往报道,D型世系中分布的大部分为红色原鸡和斗鸡,结果表明安集延鸡母系大部分来源于红色原鸡和斗鸡,并且也掺入一些家鸡母系,为多母系构成的群体

新疆小麦地方品种籽粒硬度及其Puroindoline 基因等位变异研究/Identification of the Allelic Variation of Puroindoline Alleles in Xinjiang Wheat Landraces[J]

[目的]籽粒硬度是重要的小麦品质性状,了解新生疆小麦地方品种籽粒硬度的变异类型和分布,为新疆小麦品质育种提供遗传信息.[方法]利用单籽粒硬度仪(SKCS)和PCR扩增、酶切及DNA测序技术,结合改良的Friabilin提取及电泳分析方法,对105份新疆小麦地方品种的籽粒硬度及Pina和Pint等位基因进行研究.[结果]新疆小麦地方品种以硬质类型为主,平均硬度值为63.5.新疆小麦地方品种Puroindoline基因共有9种突变型,分别是Pina-D1a/Pinb-D1a,Pina-D1a/Pinb-Dlb,Pina-D1a/Pint-D1p,Pina-D1k (null)/null,Pina-D1l/Pinb-D1a,Pina-D1r/Pinb-D1a,Pina-D1a/Pinb-D1ab,Pina-D1a/Pint-Dlac和Pina-D1b/Pinb-D1p,其中Pina-D1 r/Pinb-D1a为新发现的突变型.新疆小麦地方品种Puroindoline基因型以Pina-D1a/Pinb-D1p为主导类型,共有62份,占59.1%;其Pina-D1k(null)/null和Pina-D1 a/Pint-D1ab两种突变型与其地理来源和生态型密切相关,主要分布在南疆冬小麦中.Pina-D1a/Pinb-D1a(野生型)的硬度值显著低于突变型,Pina-Dlk(null)/null的硬度值最高,但Pins-D1k (null)/ null,Pina-D1a/Pinb-D1p和Pina-D1a/Pinb-D1ab的硬度值差异不显著.[结论]新疆小麦地方品种籽粒硬度及其Puroindoline等位变异和分布信息能为新疆小麦品质改良和引种提供理论依据

JUNO Sensitivity on Proton Decay p→νˉK+p\to \bar\nu K^+ Searches

The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this paper, the potential on searching for proton decay in $p\to \bar\nu K^+$ mode with JUNO is investigated.The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits to suppress the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via $p\to \bar\nu K^+$ is 36.9% with a background level of 0.2 events after 10 years of data taking. The estimated sensitivity based on 200 kton-years exposure is $9.6 \times 10^{33}$ years, competitive with the current best limits on the proton lifetime in this channel