不同攻角下超声速降落伞伞绳的影响研究

文章基于一种简易＂浸入边界技术＂与流固耦合方法对超声速来流条件下的三维降落伞系统进行了数值模拟。研究中,降落伞系统包括前体和伞体,两者通过伞绳连接。文章的研究目的是分析不同攻角下降落伞伞绳对于降落伞系统周围复杂非定常流场的影响,以及对降落伞性能表现的影响。结果表明：在较小的前体和伞体距离下,由于攻角的影响,非定常流场结构呈现上下不对称,并且上下伞绳激波形成时间不同步。随着攻角的增加,上下面的伞绳激波形成时间出现推迟,并且有变弱的趋势。另外,由于攻角与伞绳的综合影响,伞内表面的时间平均压力分布在5o攻角时最小,而在10o攻角时最大,阻力系数却随着攻角的增加而增加

Advance in Red-emitting Mn⁴⁺-activated Oxyfluoride Phosphors

稳定可靠的高光子能量发光(620~650 nm)红光荧光粉, 对于构建低色温、高显指荧光粉转换型白光发光二极管(WLED)至关重要。Mn⁴⁺激活红光荧光粉是当前 WLED 用荧光粉研究热点之一。本文介绍了 Mn⁴⁺离子的能级跃迁与光致发光特性, 详细叙述了目前所报道的七种 Mn⁴⁺激活含 d⁰/d¹⁰/s⁰离子氧氟化物系列红色荧光粉(如Na₂WO₂F₄:Mn⁴⁺等)的制备方法、晶体结构及其发光特性。目前⁴⁺在氧氟化物结构中得到强 R 线(零声子线)发光的情况少, 微观配位体仍是[MnF₆]或[MnO₆], 其化学稳定性和量子效率研究也很缺乏。最后对 Mn⁴⁺激活氧氟化物红光荧光粉的研究进行了展望。The stable and reliable red phosphor with high-photon energy emission (620–650 nm) is critical for the fabrication of the phosphor-converted white light-emitting diode (WLED) with low correlated color temperature and high color rendering index. Mn⁴⁺-activated phosphor is an emerging kind of red-emitting phosphor for WLED. Herein, the energy levels transition and photoluminescence characteristics of the Mn⁴⁺ ion were introduced; then, the preparation, crystal structure and luminescent properties of as-far reported seven kinds of Mn⁴⁺-doped oxyfluoride red phosphors (such as Na₂WO₂F₄:Mn⁴⁺) containing d⁰/d¹⁰ or s⁰ cations were reviewed. Currently, only in quite rare case of oxyfluoride, Mn⁴⁺ was found to exhibit strong R-line emission, with local coordination remaining as either [MnF₆] or [MnO₆]. The studies on the chemical stability and quantum efficiency of Mn⁴⁺ -doped oxyfluoride phosphors are still insufficient. Finally, we prospected the future development of Mn⁴⁺-doped oxyfluoride phosphor

Studies on chemical constituents in ethanolic extract from Acanthus ilicifolius as a pharmaceutic mangrove

目的探讨老鼠簕的化学成分。方法将老鼠簕全株粉碎后,用95%乙醇浸提3次,合并浓缩,浸膏的石油醚部位经反复硅胶柱层析分离,结合波谱学数据鉴定化合物结构。结果从石油醚部位分离得到8个化合物,分别为β-谷甾醇(Ⅰ)、豆甾醇(Ⅱ)、正十六烷酸(Ⅲ)、正二十八烷酸(Ⅳ)、4,22-二烯-3-酮豆甾烷(stig-masta-4,22-dien-3-one)(Ⅴ)、4-烯-3-酮豆甾烷(stigmast-4-en-3-one)(Ⅵ)、5,22-二烯-7-酮-3β-羟基豆甾烷(3β-hydroxystigmasta-5,22-dien-7-one)(Ⅶ)、2-唑啉酮(2-benzoxazolinone)(Ⅷ)。结论其中Ⅴ,Ⅵ,Ⅶ为首次从该植物中分离得到。Objective To study the chemical constituents of Acanthus ilicifolius.Methods The air-dried and powdered plant material was extracted with 95% ethanol.Silica gel and Sephadex LH-20 column chromotography were used in the isolation from the ethanol extracts of the whole plant,the compounds were determined on the basis of various modern spectroscopic analyses and physical constants.Results Eight compounds were isolated from the petroleum ether soluble portion,identified as β-sitosterol(Ⅰ),stigmasterol(Ⅱ),n-hexadecane acid(Ⅲ),n-octacosanic acid(Ⅳ),stigmasta-4,22-dien-3-one(Ⅴ),stigmasta-4-en-3-one(Ⅵ),3β-hydroxystigmasta-5,22-dien-7-one(Ⅶ) and 2-benzoxazolinone(Ⅷ).Conclusion CompoundⅤ,Ⅵ,Ⅶ were obtained from the genus for the first time.国家自然科学基金(30671646);; 福建省科技计划资助项目(2003Y036

钯纳米粒子体系中的近场耦合与SERS效应

利用广义米氏散射理论(gEnErAlIzEd MIE)从理论上系统研究了球形钯纳米粒子二聚体的线性光学性质及其表面增强拉曼散射效应.计算表明,粒子间的近场耦合效应对粒子对的吸收、散射和消光光谱影响显著,其表面等离子体激元共振峰的位置随粒子间隔的变小而显著红移.在耦合效应和尺寸效应的共同作用下,钯纳米粒子二聚体中“热点“位的最大SErS增强因子可达到107~108,表面平均SErS增强因子可达105~106.通过对远场和近场的对比研究,发现消光谱与粒子间的近场增强谱的谱型大致相同,但消光谱的极值峰位与SErS的最大增强峰位之间存在一定的偏离,这显示了表面等离子激元共振对远场和近场的不同影响,我们对此进行了讨论.相关结果对揭示远场与近场的关联性及探索过渡金属体系中表面增强散射的电磁场增强机理有较重要的科学意义.国家自然科学基金(20703032);国家重点基础研究发展计划(2009CB930703);福建省自然科学基金(E0710028)资助项

Expression and test of the neutralization Fab antibody against infectious bursal disease virus

为表达抗鸡传染性法氏囊病病毒(IbdV)抗体fAb并检测其中和活性,本研究将抗IbdV抗体的轻链(l)和重链片段(fd)基因分别克隆于P ET-27b(+)载体中,并转化于大肠杆菌rOSETTA(dE3)进行诱导表达。将l和fd片段包涵体蛋白变性后等量混合于复性液中,制备fAb并对其进行活性鉴定。结果显示l和fd蛋白相对分子质量大小分别为25 ku和28 ku。WESTErn blOT和ElISA检测结果表明,获得的抗体fAb大小约为50 ku,并且与VP2蛋白和不同病毒株均具有特异性结合能力。体外中和试验结果表明,获得的IbdV抗体fAb具有中和活性,可以有效阻断IbdV(b87株)对鸡胚成纤维细胞(df1)的感染。本实验获得的IbdV抗体fAb有望成为治疗Ibd的候选生物制剂,为研制治疗Ibd抗体制剂奠定了基础。To express the neutralizing Fab antibody against infectious bursal disease virus(IBDV),the gene of light chain(L)or heavy chain fragment(Fd) against IBDV was cloned into the prokaryotic expression plasmid,respectively,and then the recombinant L or Fd was expressed in E.coli Rosetta(DE3),respectively,and purified through sole denaturation and co-renaturation of inclusion body.Western blot results showed that the Fab was approximately 50 ku.ELISA results showed that the Fab exhibited binding ability and specify to VP2 for different IBDV strains.The results of neutralization test in vitro showed that the Fab exhibited neutralizing activity to IBDV-B87 strainin chicken embryo fibroblast(DF1) cells.The Fab antibody prepared in this study is expected to become a candidate drug for treatment of IBD,which laid the foundation for the treatment of IBD.黑龙江省应用技术研究与开发计划项目(GC13C104

Expression of Fusion Protein of Parathyroid Hormone and Transferrin N-terminal Half-molecule in Pichia pastoris

利用重叠PCR技术将PTH(parathyroidhormone,甲状旁腺激素)基因与TFN(transferrinN_terminalhalf_molecule,转铁蛋白N端半分子)基因在体外融合,融合基因克隆至真核表达载体pPIC9中,转化毕赤酵母GS115。转化子经甲醇诱导后,融合蛋白得到了表达并分泌到发酵上清液中。经SPSepharoseFF阳离子交换层析、PhenylSepharoseFastFlow疏水层析纯化获得了纯度大于95%的PTH_TFN样品。Westernblot分析及腺苷酸环化酶实验证明融合蛋白中的PTH具有与抗PTH抗体结合能力及刺激腺苷酸环化酶的活性,铁饱和实验证明融合蛋白中的TFN和单独的TFN具有相同铁结合能力。因而TFN可望作为PTH的天然运输载体。The fused gene (PTH_TFN) of parathyroid hormone (PTH) gene and transferring N_terminal half_molecule (TFN) gene was amplified by multiple PCR and inserted into pPIC9 vector. The recombinant plasmid pPIC9_PTH_TFN was transformed into Pichia pastoris GS115 by PEG. After methanol induction, the target protein was expressed in fermentation supernatant at high level.The fused protein PTH_TFN with purity being higher than 95% was finally obtained after purification through two_step chromatography : SP Sepharose Fast Flow and Phenyl Sepharose Fast Flow.Western blot analysis and adenylate cyclase assay proved that the fused protein exhibited the bioactivity to stimulate cAMP synthesis and the ability to bind Fe ~3+ in the Fe ~3+ saturation study as the recombinant TFN did indicating that TFN could be used as the transcellar carrier of PTH.国家高技术研究与发展项目基金资助(No.2004AA215172)。~

1978～2008年中国湿地类型变化

分别基于美国陆地卫星(Landsat MSS/TM/ETM+)和中巴资源卫星(CBERS-02B)影像数据,以人工目视解译为主,完成了中国1978～2008年4期(基准年分别为1978,1990,2000和2008年)湿地遥感制图,并进行了大量的室内外验证.在此基础上,对我国湿地现状及近30年来湿地变化进行了初步分析,得到以下主要结论:(ⅰ)截止2008年,中国湿地面积约为324097km2,其中以内陆沼泽(35%)和湖泊湿地(26%)为主.(ⅱ)1978～2008年,中国湿地面积减少了约33%,而人工湿地增加了约122%.过去30年里湿地减少的速度大幅降低,由最初5523km2/a(1978～1990年)降为831km2/a(2000～2008年).(ⅲ)减少的自然湿地(包括滨海湿地和内陆湿地),其类型变化由湿地向非湿地转化的比例逐渐降低.初期(1978～1990年)几乎全部(98%)转换为非湿地;在1990～2000年间减少的自然湿地约有86%转化为非湿地,而在2000～2008年,这一比例下降为77%.(ⅳ)气候变化和农业活动是中国湿地变化的主要驱动因素,湿地变化在中国分为三大不同特征区域,即西部三省/自治区(西藏、新疆和青海)、北部两省/自治区(黑龙江和内蒙古)和其他省市区.其中西部区域尤其是青藏高原,湿地变化的驱动因子以气候增温为主;新疆湿地由于气候增温和农业活动共同作用造成变化不大.北部省/自治区的湿地变化则主要由农业活动引起;而其他省市区的湿地变化几乎完全受控于人类的农业经济活动

卫星激光网络应用技术研究

卫星互联网的快速发展，使得带宽及频谱资源的紧缺问题日益凸显。卫星激光通信大带宽及无频谱约束的特点，使其成为缓解射频资源紧张和提升通信带宽的有效手段。文章通过对国内外卫星激光通信发展的调研，总结出该领域未来的技术发展趋势，同时针对所涉及的网络重构和高效编码等关键技术进行了设计与仿真验证，为我国卫星激光通信的研究提供了理论与技术参考

电路仿真专用芯片设计

电路仿真对于电信网向分组交换网的平稳过渡有着重要意义。文章根据相关标准提出并实现了一种电路仿真专用芯片的设计方案,并对其中主要功能模块和关键算法作出了详细说明,包括一种全数字的自适应时钟恢复方法、动态深度缓冲算法等。目前该设计已经通过了验证和在实际网络环境中的测试

New progresses on UAV swarm confrontation

无人机集群对抗是未来无人机作战的重要模式,它是一群无人机对另一群无人机进行拦截而形成的空中协作式的缠斗,对抗中无人机具有自组织、自适应特点和拟人; 思维属性,通过感知环境,对周围态势进行判断,依据一定的行为规则,采取攻击、避让、分散、集中、协作、援助等有利策略,使得在整体上涌现出集群对抗系统; 的动态特性。本文对近年来无人机集群对抗的研究进展进行综述,分析总结相关的关键技术,对研究思路和方法进行深入探讨,以期为从事无人机集群对抗建模研究; 提供参考。Unmanned aerial vehicle (UAV) swarm confrontation will be an important; combat mode for UAVs in the future. It is coordinated airborne dogfight; between two adversary UAV swarms when one side attempts to intercept the; other. UAVs in the conflict have the abilities of self- organization and; self- adaption and the property of human- like thinking. By sensing; environment, UAVs can evaluate their surrounding situation and take; actions to their advantages, like target attack, evasion, separation,; concentration, coordination, fire support, etc. according to their; behavior regularities. The interaction process between UAVs and; environments, as a whole, exhibites nonlinear dynamic characteristics; UAV swarm confrontation is a nonlinear dynamic complex system and also; is an emerging research field, therefore, it has received extensive; attention. This paper reviews the recent research advances on UAV swarm; confrontation, analyzes and summarizes its key techniques as well as; discusses related study thoughts and approaches. The paper is also; expected to be a reference to the research of modeling of UAV swarm; confrontation.国家自然科学基金项目; 2016年度航空科学基金项