紫外光引发的玉米淀粉在软材料表面的改性

以玉米淀粉作为改性剂、二苯甲酮（BP）做光引发剂对聚合物材料表面进行紫外光偶合反应,用X-射线电子能谱(XPS)、水接触角(CA)和扫描电子显微镜(SEM)对改性后的聚合物表面进行了结构和性能表征。结果表明,玉米淀粉被固定到CPP膜表面的最佳条件为0.03g/L玉米淀粉、1.0g/L BP、12.0mW/cm²光强和8min光照时间。玉米淀粉改性后的CPP膜的接触角可由105.0°变为66.3°。随着玉米淀粉的初始浓度的增加,改性CPP膜的表面水接触角先随之下降然后略有上升;延长光照时间和增加光强均会使玉米淀粉改性的CPP膜的表面水接触角随之下降。玉米淀粉改性后的CPP膜的表面形成了一定规则形状的颗粒结构。     

流媒体技术及其在企业中的应用

介绍了流媒体技术的概念、工作原理及其特点，叙述了流媒体技术在企业中的4种主要应用，展望了该技术在企业应用中的广阔前景。     

A≈250区原子核转动谱的系统研究

利用几个原子核转动谱公式系统研究了A≈250质量区偶偶核与奇A核的转动谱,这些公式包括Bohr-Mottelson提出的按I（I＋1）展开的AB（ABC和ABCD）公式,按ω2展开的Harris公式以及吴崇试、曾谨言提出的ab公式.结果显示,在二参数公式中,相较于AB公式和Harris公式,ab公式能够更好地描述A≈250质量区的偶偶核基态转动带.对于这个质量区的奇A核,除了K=1/2的转动带之外,ab公式也能给出较好的描述.对于实验观测到的253No的一条转动带,组态指定存在争议.利用ab公式研究表明,该转动带的组态为7/2＋[624].     

面向HgCdTe红外焦平面探测器应用的分子束外延材料研究进展

报道了针对第三代碲镉汞红外焦平面的应用需求进行的碲镉汞分子束外延研究进展.面向大规模HgCdTe红外焦平面探测器的应用,开展了大面积替代衬底上的分子束外延技术研究,报道了在大面积替代衬底上的碲镉汞分子束外延材料的晶体质量、表面形貌和组份均匀性的改善方法和研究结果.512×512及以上规模的中波、短波碲镉汞面阵器件制备验证表明Si基碲镉汞材料满足应用需求.围绕甚长波红外焦平面探测器及雪崩红外焦平面探测器的研制需要,开展了低缺陷的ZnCdTe基碲镉汞分子束外延研究.外延获得的HgCdTe外延材料均匀性得到明显提高.经过外延条件的优化,厚度为10μm的HgCdTe/ZnCdTe(组分x=0.22)分子束外延材料位错密度最好结果为3×104 cm-2,双晶半峰宽小于25弧秒.     

Geochronology and geochemistry of the Fangcheng Neoproterozoic alkali-syenites in East Qinling orogen and its geodynamic implications

Finding of Neoproterozoic syenites at Fangcheng in the northern Qinling region of the East Qinling orogen provides an important constraint on timing of tectonic transformation to extensional regime. The alkaline pluton consists mainly of nepheline syenite, aegirine syenite, and alkali-feldspar syenite. The syenites are of intermediate （SiO2 = 54%-62%）, rich in alkali （K2O＋Na2O = 12%-15%）, aluminum （Al2O3= 16.81%-23.26%） and large ion lithophile elements （LILE）, without any obvious Nb, Ta, Zr, and Hf anomalies. The Fangcheng syenites are geochemically characterized by relative enrichment of LREE, minor differentiation of HREE, significant negative Eu anomalies （Eu = 0.13-0.23）, less negative εNd（t） values of -1.37 to-3.90, young Nd model ages of 1364 to 1569 Ma, and high zircon saturation temperatures of 915 to 1044℃. The syenitic magmas probably originated from small proportion melting of upper mantle in an extensional regime of intraplate-anorogenic tectonic setting, and have been slightly contaminated by crustal materials during ascending and/or emplacement. LA-ICP-MS zircon U-Pb dating yields ages of 844.3±1.6 Ma （MSWD=0.86）, suggesting that the Fangcheng alkaline syenites formed in the early Neoproterozoic. They are the oldest Neoproterozoic alkaline rocks ever recognized in the Qinling orogen as well as in South China. This implies that the tectonic regime of the Qinling region would have transformed from post-collisional stretch to intraplate-anorogenic extension no later than 844 Ma.     

Sinorhizobium meliloti nifA gene exerts a pleiotropic effect on nodulation through the enhanced plant defense response

Sinorhizobium meliloti nifA gene is required for the expression of a bunch of nif and fix genes. Here, we report its pleiotropic effects on the nodule formation. Compared with wild type strain, nifA mutant sig- nificantly reduced nodule suppression rate in split-root system. The plants inoculated with mutant strain produced lower amount of daidzein and less necrotic cells on their roots. In addition, the defense genes failed to be evoked by nifA mutant at the early nodulation stage. These findings indicated that host defense response was one of the mechanisms mediated by nifA gene to regulate nodule formation during symbiosis. Even though nifA mutant could increase the number of nodules in host plant, it synthesized lower Nod factors than wild type. This suggested that nifA gene mediated multiple and diverse instances in nodulation formation.     

普洱茶的非线性光学效应与光速调控

利用Z扫描方法研究了普洱茶的非线性光学效应, 发现普洱茶水溶液在连续光下具有很高的非线性折射率, 与CS2相比高达6个数量级, 尤其是在普洱茶水溶液中观察到了光速减慢到超光速的转换过程, 实验结果显示了光波位相耦合色散效应导致光速变化机制的普适性.     

含钴酞菁聚芳醚酮降解三氯苯酚的催化性能

成功地合成了钴酞菁封端(T-PAEK-CoPc)和侧链悬挂钴酞菁的聚芳醚酮(S-PAEK-CoPc), 两种聚合物均具有良好的化学和热稳定性, 以及良好的溶解性, 并在可见光范围内具有较强的吸收. 研究了这两种聚合物作为高分子催化剂降解2,4,6-三氯苯酚(TCP)的催化性能, 结果表明, 两种聚合物显示了良好的催化性能, 且S-PAEK-CoPc的催化效果比T-PAEK-CoPc更好, 反应7 h后三氯苯酚的降解率超过70%. 两种聚合物可以作为苛刻条件下降解三氯苯酚的催化剂.     

Trainable unit selection speech synthesis under statistical framework

This paper proposes a trainable unit selection speech synthesis method based on statistical modeling framework. At training stage, acoustic features are extracted from the training database and statistical models are estimated for each feature. During synthesis, the optimal candidate unit sequence is searched out from the database following the maximum likelihood criterion derived from the trained models. Finally, the waveforms of the optimal candidate units are concatenated to produce synthetic speech. Experiment results show that this method can improve the automation of system construction and naturalness of synthetic speech effectively compared with the conventional unit selection synthe- sis method. Furthermore, this paper presents a minimum unit selection error model training criterion according to the characteristics of unit selection speech synthesis and adopts discriminative training for model parameter estimation. This criterion can finally achieve the full automation of system con- struction and improve the naturalness of synthetic speech further.     

Biogeographical patterns of the diet of Palearctic badger:Is badger an earthworm specialist predator?

Badgers were hypothesized as an earthworm specialist predator.We reviewed spatial patterns and food habits of the Eurasian badger(Meles spp.) in relation to geographical variables like latitude,elevation,aspects,and environmental variables,such as temperature,snow cover depth,precipitation,primary productivity,and human influence.The relative frequencies of occurrence of food items in the diets of badgers in 19 studies across 22 localities worldwide were included in the analysis plus the data from our study on the badger diet on the Qinghai-Tibetan Plateau.Principal component analysis(PCA) was used to extract the main components of dietary composition.Multiple regression analysis was applied to reveal the relationship between trophic diversity and the main PCA factors and biogeographical variables.We found a clear latitudinal gradient in the dietary composition of badgers,which was characterized by a greater consumption of insects and reptile in southern area and a higher intake of earthworm in northern regions.Nevertheless,badgers are not an earthworm specialist predator.Furthermore,trophic diversity of badger diets was significantly positively correlated with latitude and human activity.Abundance and availability of foods appear to determine badger foraging tactics.Badgers are adept in exploiting local resources and our results confirm that badgers are generalist predators with opportunistic foraging behavior across their entire distribution range.