藤三七中一个新黄烷醇和抗HIV活性成分

利用各种色谱(硅胶和凝胶)方法,从藤三七[Boussingaultia gracilis Miers var.pseudobaselloides Bailey]的70%(体积分数)的乙醇提取物中分离得到2个黄烷醇类化合物(1,2)和4个黄酮类化合物(3～6).采用UV,IR,MS 和1D,2D NMR方法,分别鉴定出如下化合物: 7-羟基-5-甲氧基-8-甲基-6-甲酰基-3,4-黄烷二醇,命名为藤三七醇A(1);4,7-二羟基-5-甲氧基-8-甲基-6-甲酰基黄烷(2);7-O-methylunonal(3);5,7-二羟基-6,8-二甲基-2-苯基-4H-1-苯并吡喃-4-酮(4);Desmosflavone(5)和Demethoxymatteucinol(6).其中化合物1是一个新的黄烷二醇化合物,化合物2～6为首次从该植物中分离得到.抗HIV-1活性筛选结果表明: 化合物1,2,5,6对HIV-1诱导合胞体的形成具有一定的抑制作用,其半数有效浓度(EC50)分别为45.09,48.73,55.47 和 82.75 μmol/L,治疗指数(TI)分别为1.41,1.20,7.15 和》8.51.

One new flavanoid and Anti-HIV active constituents from boussingaultia gracilis miers var. pseudobaselloides bailey

Boussingaultia gracilis Miers var. pseudobaselloides Bailey (Basellaccae) is a folk medicine used as an analgesic and supplements, only a few research was reported on the chemical constituents of this plant. This paper presented its chemical and anti-HIV

影响牛胚胎移植妊娠率的因素分析

相关研究得到云南省省院省校合作项目（YK98004）资助.

独立思考 敢于创新

刘建康院士是著名的鱼类学家、生态学家。他致力于淡水鱼的生态学研究,取得显著的社会效益和经济效益。他以极大的热情投身到湖北省梁子湖和长江干流的鱼类的生态调查研究,以及东湖渔业生产、生态学的研究,从理论和实践上为我国淡水渔业与淡水生态学的发展作出了贡献。他总结的“重视科学实验,着眼社会实践;不唯上,不唯书,不唯权威;独立思考,敢于创新”的治学格言,令人深受启发。现将他在《科学的道路》发表的“独立思考,敢于创新”一文; 经作者同意,转载于后。

Distribution matching for transduction

Many transductive inference algorithms assume that distributions over training and test estimates should be related, e.g. by providing a large margin of separation on both sets. We use this idea to design a transduction algorithm which can be used without modification for classification, regression, and structured estimation. At its heart we exploit the fact that for a good learner the distributions over the outputs on training and test sets should match. This is a classical two-sample problem which can be solved efficiently in its most general form by using distance measures in Hilbert Space. It turns out that a number of existing heuristics can be viewed as special cases of our approach.

A novel extremely broadband superluminescent diode based on symmetric graded tensile-strained bulk InGaAs

A novel broadband superluminescent diode (SLD), which has a symmetric graded tensile-strained bulk InGaAs active region, is developed. The symmetric-graded tensile-strained bulk InGaAs is achieved by changing the group III TMGa source flow only during its growth process by low-pressure metalorganic vapor-phase epitaxy (LP-MOVPE), in which the much different tensile strain is introduced simultaneously. At 200mA injection current, the full width at half maximum (FWHM) of the emission spectrum of the SLID can be up to 122nm, covering the range of 1508-1630nm, and the output power is 11.5mW.

Coherent transport through a quantum dot embedded in a double-slit-like Aharonov-Bohm ring

Coherent transport through a quantum dot embedded in one arm of a double-slit-like Aharonov-Bohm (AB) ring is studied using the Green's function approach. We obtain experimental observations such as continuous phase shift along a single resonance peak and sharp inter-resonance phase drop. The AB oscillations of the differential conductance of the whole device are calculated by using the nonequilibrium Keldysh formalism. It is shown that the oscillating conductance has a continuous bias-voltage-dependent phase shift and is asymmetric in both linear and nonlinear response regimes.

用纳米棒ZnO作模板生长无支撑的AlN纳米晶

用金属有机物气相外延在纳米棒ZnO模板上沉积AlN薄膜.SEM测试表明该薄膜形成了一种倾倒纳米棒的表面.而GIXRD测试进一步证实它是纤锌矿结构的AlN,晶粒尺度约为12nm,接近于ZnO纳米棒的直径(30nm).这意味着纳米棒结构的ZnO能限制AlN的横向生长.此外,高温下用H_2刻蚀ZnO直接在生长中实现了外延层的剥离.最终得到了无支撑的AlN纳米晶,完整无破损的区域约为1cm×1cm.定义这个生长机制为"生长-刻蚀-合并"过程.

An Electroabsorption Modulator Monolithically Integrated with a Semiconductor Optical Amplifier and a Dual-Waveguide Spot-Size Converter

A semiconductor optical amplifier and electroabsorption modulator monolithically integrated with a spotsize converter input and output is fabricated by means of selective area growth,quantum well intermixing,and asymmetric twin waveguide technology. A 1550-1600nm lossless operation with a high DC extinction ratio of 25dB and more than 10GHz 3dB bandwidth are successfully achieved. The output beam divergence angles of the device in the horizontal and vertical directions are as small as 7.3°× 18.0°, respectively, resulting in a 3.0dB coupling loss with a cleaved single-mode optical fiber.