Genetic Diversity Caused by Environmental Stress in Natural Populations of Niupidujuan as Revealed by RAPD Technique

Multiplex environmental factors are generally expected to have significant effects on genetic diversity of plant populations.In this study,randomly amplified polymorphic DNA(RAPD) technique was used to reveal the genetic diversity in the same species of four populations collected from Niupidujuan(Rhododendron chrysanthum) at different altitudes,an endangered species,endemic to Northeast China.Initially,twenty informative and reproducible primers were chosen for final RAPD analysis.A total of 152 clear bands...     

Immunofluorescent Labeling of Human HepG2 Cells with CdTe Quantum Dot Probe Conjugated with Anti-pan CK MAb

A relatively sensitive, specific, and photostable method for the detection of cytokeratin of cancer cells via conjugation with cadmium telluride quantum dots(CdTe QDs) was described. Water soluble CdTe QDs were conjugated to anti-pan-cytokeratin(CK) monoclonal antibody(MAb) through coupling reagent [1-ethyl-3-(3-dimethyla- mino propyl)carbodiimide, EDC] and the conjugates were purified by dialysis. The expression of pan CK protein in HepG2 cells was observed by immunocytochemistry and direct immunofluoresce...     

掺入Eu的钛酸钡纳米晶陶瓷材料制备与电子结构特征

以Eu2O3、TiO2和BaCO3为原材料,在高温高压的极端条件下(4．0GPa,1090℃)采用固相反应法制备了结构均匀的新陶瓷材料Ba1-xEuxTiO3(x=0.1-0.4),样品显示灰黑色。当x增加到0．5时,出现ABO3型钙钛矿相和Eu2Ti2O7焦绿石相共存。X射线衍射图样显示Eu离子对A位Ba离子的均匀替代。并随着Eu含量的增加,结构向高对称性转变。通过对X射线衍射数据计算,表明材料结晶在平均粒度为几十纳米的数量级。X射线电子能谱(XPS)分析说明：在高压的作用下,Eu^3 离子部分被还原,在晶体结构中以Eu^3 离子(4f^6)和亚稳态Eu^2 离子(4f^7终态构形)稳定共存。同时在样品表面存在大量的吸附氧。Ba1-xEuxTiO3材料的电中性由亚稳态Eu^2 离子和吸附氧(O^-)共同补偿。     

ZnO薄膜的掺杂特性

通过MOCVD方法生长的ZnO薄膜一般为富锌生长,呈n型电导,要想得到高阻或低阻p-ZnO薄膜需要对其进行掺杂施主或受主杂质.主要研究在生长过程中通过NH₃对ZnO薄膜进行氮掺杂的情况,利用优化生长条件,即生长温度为610℃,Ar气(携带DEZn)流量为4sccm,O₂流量为120sccm,N₂流量为600sccm,得到在NH₃流量为80sccm时生长样品的结晶质量最高,在掺杂薄膜中NH₃流量高于或低于80sccm时,样品的表面形貌都将变差,只有在80sccm时表面粗糙度最低晶粒最小,表明该流量下获得的样品表面较光滑致密.所以80sccmNH₃流量为在R面蓝宝石上生长<110>取向ZnO薄膜的最佳掺杂流量.Hall测量结果表明,NH₃流量为50sccm的样品电导呈弱p型,电阻率为102Ω·cm,空穴载流子浓度为+1.69×10¹⁶cm^-3,迁移率为3.6cm²·V^-1·s^-1;当NH₃流量增加时样品的电导呈n型,电阻率最高达10⁸Ω·cm,我们认为与进入ZnO薄膜的H的量有关,并对其变化机理进行了详细的分析.     

Highly efficient Nd:YAG/LBO laser at 473 nm under direct 885-nm diode laser pumping

<正>In diode pumped Nd:YAG lasers,the quantum defect is the most important parameter determining the thermal load of the laser crystal,which can be dramatically reduced by pumping directly into the upper laser level.A compact folded three-mirror cavity with a length of 105 mm is optimized to obtain a highly efficient 473-nm laser.When the absorbed pump power(with 15.8-W incident pump power) at 885 nm into Nd:YAG is 10 W,a continuous-wave 473-nm blue laser as high as 2.34 W is achieved by LBO intra-cavity frequency doubled.The optical-to-optical conversion efficiency is 14.8%.To the best of our knowledge, this is the highest efficiency at 473 nm by an intra-cavity doubled frequency Nd:YAG laser.     

Etoposide Induces Mitochondria-Associated Apoptotic Cell Death in Human Gastric Carcinoma Cells

Recent observations indicate that the resistance of apoptosis is an important process of tumor metastasis and metastases are the cause of 90% of human cancer death. Etoposide, a semisynthetic derivative of the podophyllotoxins, is a clinically used anti-cancer reagent, but the effects of it on metastatic gastric carcinoma cells are totally unknown. In this study, etoposide induced apoptotic cell death in human gastric adenocarcinoma cell line SGC-7901, derived from metastatic lymph nodes, as evidenced by the analysis of DNA fragmentation, apoptotic body formation, caspase activation, and apoptosis specific changes in cell morphology is demonstrated. The depolarization of mitochondrial membrane and the release of cytochrome c were most early events in etoposide treated SGC-7901 cells, and were followed by caspase-3 activation and PARP cleavage. Caspase-8 activation was not detected under the same condition. Thus, it was proposed that etoposide induces caspase-associated apoptotic cell death in human metastatic gastric carcinoma, which is initiated by mitochondrial cytochrome c release.     

Electroless Nickel Plating and Electroplating on FBG Temperature Sensor

Metal-coated fiber Bragg grating（FBG）temperature sensors were prepared via electroless nickel（EN）plating and tin electroplating methods on the surface of normal bare FBG.The surface morphologies of the metal-coated layers were observed under a metallographic microscope.The effects of pretreatment sequence,pH value of EN plating solution and current density of electroplating on the performance of the metal-coated layers were analyzed.Meanwhile, the Bragg wavelength shift induced by temperature was monitored by an optical spectrum analyzer.Sensitivity of the metal-coated FBG（MFBG）sensor was almost two times that of normal bare FBG sensor.The measuring temperature of the MFBG sensor could be up to 280℃,which was much better than that of conventional FBG sensor.     

膨润土吸附水溶液中微量氯仿的研究

针对水中微量氯仿的吸附脱除和粉末状膨润土吸附剂实际应用中难以分离的问题,以河北省灵寿县膨润土制备的钛柱撑膨润土、成型膨润土及成型钛柱撑膨润土为吸附剂,于25℃条件下对水溶液中微量氯仿的脱除进行了研究,测得了被吸附物浓度、吸附时间对吸附过程的影,及膨润土经过不同处理后的结构变化。结果表明,钛柱撑膨润土具有优越的吸附性能,并且成型之后吸附性能仍与粉末状膨润土相当,而成型膨润土由于晶层塌陷几乎没有吸附性能。此外还测定了成型钛柱撑膨润土对氯仿的吸附等温线。     

单目视觉的同时三维场景构建和定位算法

同时场景构建和定位算法是机器人自主导航的重要组成部分.针对传统算法不能应用于室外环境和缺乏定量分析的缺点,提出了一种单摄像机恢复场景三维结构和摄像机位姿的新算法.提出了视频序列关键帧提取方法,降低了运算复杂度;利用特征点对和摄像机内参量计算场景三维结构和关键帧的位姿并提出一种估计关键帧位姿的简便方法;最后,提出一种兼顾优化效果和运算复杂度的自适应光束法平差算法优化场景结构和摄像机位姿,并生成适于机器人导航的数字高程图.室内和室外多种场景下的定量和定性实验结果表明,绕行误差低于4%,该算法能够接近实时准确实现同时场景构建和摄像机定位.     

艾奇逊炉提纯碳纳米管的组织结构性能表征

碳纳米管作为锂离子电池正极导电剂已经在中国得到了普遍应用,作为电池导电剂的碳纳米管需要提纯处理。本文研究了利用艾奇逊炉对化学气相沉积的碳纳米管在3 000℃进行提纯处理后的组织结构和电学性能,利用扫描电子显微镜(SEM),电子能谱仪(EDS),等离子体发射光谱仪(ICP),红外光谱仪(FT-IR),热重分析仪(TGA),X射线光电子谱仪(XPS),拉曼光谱分析仪,四探针薄膜电阻仪对艾奇逊炉提纯的碳纳米管进行了检测。结果表明高温提纯的碳纳米管的含铁量可降低到71ppm,氧化物含量低于0.45wt%,晶格缺陷大幅减少,石墨组织结构完整,表面官能团少,具有体积电阻率0.050～0.035Ω·cm,作为电池电极的导电材料,可以用于动力电池正极。