KF4-和KF4系列超卤化物稳定性及热裂解的理论研究

目的对KFn-和KFn(n=1～4)系列超卤化物进行理论研究。方法采用密度泛函理论B3LYP/6-311+G(3df)方法。结果得到了KF n-和KFn系列卤化物的稳定构型、垂直电离能VDE、垂直电子亲合能EAvert、绝热电子亲合能EAad、同位素效应及裂解反应热力学信息。结论同位素效应不影响VDE,EAvert,EAad及裂解反应热力学能变的值。中性物质每一步的裂解均易于其负离子的对应裂解。相对电离而言,热裂解更容易破坏该类负离子。     

烟草玉米黄质环氧化酶基因的转录表达模式及其功能研究

通过Real-time PCR检测了普通烟草(Nicotiana tabacum)红花大金元的玉米黄质环氧化酶(Zeaxanthin epoxidase,ZE)ZE基因在盛花期不同器官中的表达量.利用烟草脆裂病毒诱导的基因沉默(VIGS)技术抑制本氏烟草(Nicotiana benthamiana)ZE基因的表达,在该基因沉默后,Real-time PCR检测其上游基因的表达变化;同时检测烟草中质体色素(β-胡萝卜素、紫黄质、新黄质、叶黄质、叶绿素a和叶绿素b)含量的变化.结果显示:ZE基因在盛花期的第10位叶片、第15位叶片和花萼中表达量较高.与对照组相比,在ZE基因沉默后,其上游的基因八氢番茄红素合成酶(PSY)、八氢番茄红素脱氢酶(PDS)、ζ-胡萝卜素脱氢酶(ZDS)、类胡萝卜素异构酶(CRTISO)、番茄红素β-环化酶(β-LCY)、胡萝卜素β-环羟化酶(β-OHase)和紫黄质脱环氧化酶(VDE)的表达量降低;烟草中质体色素的含量降低.以上结果说明:ZE基因作为类胡萝卜素合成通路下游的基因在该通路中发挥着重要的调控作用,该基因表达量的变化可以影响烟草中质体色素的含量,与烟草的光合生理过程也存在着密切关系.     

杭州微光电子设备厂

杭州微光电子设备厂是浙江省高新技术企业，中国制冷学会、中国机电产品进出口商会团体会员，余杭区工业百强企业，2006浙江省最具成长性中型企业100佳，企业信用等级AAA。企业通过ISO9001质量体系认证、ISO14001环境体系认证。产品通过生产许可证及CCC认证，并取得CE、RoHS、VDE、UL认证。     

一种新型聚合物VDE用于快速吸附水中的硝酸盐

针对水中硝酸盐污染的问题， 合成一种新型的聚合物乙烯基咪唑/二溴癸烷/二甲基丙烯酸乙二醇（VDE）， 通过扫描电子显微镜（SEM）、 Fourier变换红外光谱仪（FT-IR）和X射线光电子能谱（XPS）对其结构进行表征， 并研究其在含硝酸盐水溶液的最佳剂量比、 pH值、吸附温度、 吸附时间以及重复利用性. 结果表明， 在15 ℃， pH=4时， VDE对硝酸盐氮的吸附量通过Langmuir模型拟合为28.31 mg/g， 该吸附过程在10 min可达到平衡， 且符合准一级和准二级动力学拟合模型， 在5次吸附/脱附实验后， 其吸附量仍可达到首次使用吸附量的95.5%， 表明该材料可有效净化低质量浓度的硝酸盐废水.      

加速度系统的结点化模型仿真

利用在Zeni VDE平台下建立的梁、平板质量、集总质量、气隙、压膜阻尼和锚点等结点化基本单元模型,对一种电容式加速度计系统进行了一系列的仿真,仿真内容包括静态仿真,时域仿真和频域仿真等。仿真结果和商用仿真工具ANSYS的仿真结果以及试验数据保持良好的一致。     

CJXI-09-22交流接触器

CJXI 系列交流接触器参照采用 IEC158、IEC337、VDE0660等国际和国外先进标准,其技术性能与德国西门子公司3TB 系列产品相当,并能等同互换使用。该产品具有结构紧凑、体积小、重量轻、吸合力大、通用性强、机械寿命长(经长城电器试验研究所测试,工作寿命可达1000万余次),带电部     

异双核阴离子NaMgCl4−的超卤素性质

利用MP2/6-311+G(3df)理论方法得到了稳定的异双核超卤素阴离子NaMgCl4?.NaMgCl4?阴离子的2个中心原子可以通过3个或2个氯原子连接.NaMgCl4?具有很大的垂直电子脱附能(VDE,6.573 eV和6.081 eV),所以可以判定为超卤素阴离子.研究发现配体原子及额外电子分布影响所研究的超卤...     

线性矩阵方程的梯度法神经网络求解及其仿真验证

 介绍一种基于梯度法的Hopfield神经网络在线求解线性矩阵方程,并且探讨其MATLAB仿真技术以验证该神经网络在求解线性矩阵方程问题时的准确性和有效性。仿真过程中用以下几种重要技术手段：①Kronecker乘积,用来将描述该神经网络的矩阵微分方程（MDE）转化为向量微分方程(VDE),即标准的给定初始值常微分方程（ODE）;②MATLAB指令“ode45”,用来仿真上述转化后的给定初始值常微分方程;③各种激励函数的编码实现,用以检验该神经网络系统的收敛性和存在实现误差时的鲁棒性。仿真结果同理论分析的对应与一致,进一步证实基于梯度法的Hopfield神经网络在求解固定系数线性矩阵方程中具有很好的效验。     

基因科技隐私法律问题

随着基因科技的发展,基因隐私成为人们关注的焦点。作为基因科技发展的必然产物,基因隐私较其它隐私有自身的特点,基因隐私权涉及的内容也很多。要处理好基因隐私保护与基因科技发展的关系,使基因隐私得到有效保护,切实维护权利人的基因隐私权,又使基因科技得到快速发展,为人类造福。     

提取基因标签的方法及识别率提高的方法

目的用较少的基因标签准确地来识别结肠癌患者。方法根据基因之间的相关性,采取模糊聚类分析法对大量基因进行聚类。引入各基因与基因中心向量的距离建立优化模型。其次根据基因在样本中的分布特征将基因分为突变基因和无关基因。综合基因的这两个特征建立优化模型。为了提高识别率,采用蒙特卡罗方法考虑了基因中的噪声。最后,考虑到已知的基因标签的特征,重新建立了优化模型。结果在不考虑噪声时,得到8个基因标签,正确识别率为72.6%;加入噪声之后正确识别率为85.00%;加入已知基因标签之后正确识别率为87.1%;加入符合已知基因标签特征的全部基因标签得到25个基因标签,识别率提高到了96.7%。结论考虑的基因特征越多,正确识别率越高。     

Molecular cloning, in vitro expression and enzyme activity analysis of violaxanthin de-epoxidase from Oryza sauva L.

The violaxanthin de-epoxidase gene was cloned from rice (Oryza sauva subsp japonica). The full length of the cDNA is 1887 bp, encoding a 446-amino acids protein with the transit peptide of 98 amino acids. The bacterial expression vector pET-Rvde was constructed and the expression quantity of the exogenous protein increased with the induction time by 0.4 mmol/L IPTG. Its molecular weight was similar with that of the native VDE. Western blotting indicated that the expressed protein has immunological reaction with the VDE polyclonal antibody. The absorbance spectrum together with xanthophyll pigments quantification by HPLC demonstrated that the expressed VDE has its enzyme activity, which can de-epoxidate violaxanthin into antheraxanthin and zeaxanthin in vitro.     

Molecular cloning, in vitro expression and enzyme activity analysis of violaxan-thin de-epoxidase from Oryza sativa L.

The violaxanthin de-epoxidase gene was cloned from rice (Oryza sativa subsp. japonica). The full length of the cDNA is 1887 bp, encoding a 446-amino acids protein with the transit peptide of 98 amino acids. The bacterial expression vector pET-Rvde was constructed and the expression quantity of the exogenous protein increased with the induction time by 0.4 mmol/L IPTG. Its molecular weight was similar with that of the native VDE. Western blotting indicated that the expressed protein has immunological reaction with the VDE polyclonal antibody. The absorbance spectrum together with xanthophyll pigments quantification by HPLC demonstrated that the expressed VDE has its enzyme activity, which can de-epoxidate violaxanthin into antheraxanthin and zeaxanthin in vitro.     

Identification and comparison of two sequence elements that confer cell-type specific transcription in yeast

The MAT alpha 2 protein of budding yeast represses a set of genes; if the MATa1 protein is also present, a further set of genes is repressed. DNA sequence comparisons reveal a 20-base pair 'operator' sequence that is present in genes repressed by a1/alpha 2. A related, but distinct, sequence is found in genes repressed by alpha 2 alone.     

Sequence identification of 2,375 human brain genes.

We recently described a new approach for the rapid characterization of expressed genes by partial DNA sequencing to generate 'expressed sequence tags'. From a set of 600 human brain complementary DNA clones, 348 were informative nuclear-encoded messenger RNAs. We have now partially sequenced 2,672 new, independent cDNA clones isolated from four human brain cDNA libraries to generate 2,375 expressed sequence tags to nuclear-encoded genes. These sequences, together with 348 brain expressed sequence tags from our previous study, comprise more than 2,500 new human genes and 870,769 base pairs of DNA sequence. These data represent an approximate doubling of the number of human genes identified by DNA sequencing and may represent as many as 5% of the genes in the human genome.     

The complete DNA sequence of yeast chromosome III.

The entire DNA sequence of chromosome III of the yeast Saccharomyces cerevisiae has been determined. This is the first complete sequence analysis of an entire chromosome from any organism. The 315-kilobase sequence reveals 182 open reading frames for proteins longer than 100 amino acids, of which 37 correspond to known genes and 29 more show some similarity to sequences in databases. Of 55 new open reading frames analysed by gene disruption, three are essential genes; of 42 non-essential genes that were tested, 14 show some discernible effect on phenotype and the remaining 28 have no overt function.     

The DNA sequence and biological annotation of human chromosome 1

The reference sequence for each human chromosome provides the framework for understanding genome function, variation and evolution. Here we report the finished sequence and biological annotation of human chromosome 1. Chromosome 1 is gene-dense, with 3,141 genes and 991 pseudogenes, and many coding sequences overlap. Rearrangements and mutations of chromosome 1 are prevalent in cancer and many other diseases. Patterns of sequence variation reveal signals of recent selection in specific genes that may contribute to human fitness, and also in regions where no function is evident. Fine-scale recombination occurs in hotspots of varying intensity along the sequence, and is enriched near genes. These and other studies of human biology and disease encoded within chromosome 1 are made possible with the highly accurate annotated sequence, as part of the completed set of chromosome sequences that comprise the reference human genome.     

A conserved DNA sequence in homoeotic genes of the Drosophila Antennapedia and bithorax complexes

A repetitive DNA sequence has been identified in the Drosophila melanogaster genome that appears to be localized specifically within genes of the bithorax and Antennapedia complexes that are required for correct segmental development. Initially identified in cloned copies of the genes Antennapedia, Ultrabithorax and fushi tarazu, the sequence is also contained within two other DNA clones that have characteristics strongly suggesting that they derive from other homoeotic genes.