液体金属吸附促进位错发射的分子动力学研究

结果表明，Al吸附Ga后可使发现位错的临界应力强度因子从K_(Ie)=0.5MPam~(1/2)降为K_(Ie)(L)=0.4Mpam~(1/2)；对Cu则从K_(Ie)=0.55MPam~(1/2)降为K_(Ie)(L)=0.45MPam~(1/2)，即Ga吸附后能促进位错的发现。另外，吸附Ga之后裂尖前方容易产生空位团及Frank位错。

Comparison-speed liquid jets

The performance of a small high-speed liquid jet apparatus is described. Water jets with velocities from 200 to 700 m/s were obtained by firing a deformable lead slug from an air rifle into a stainless steel nozzle containing water sealed with a rubber diaphragm. Nozzle devices using the impact extrusion (IE) and cumulation (CU) methods were designed to generate the jets. The effect of the nozzle diameter and the downstream distance on the jet velocity is examined. The injection sequences are visualized using both shadowgraphy and schlieren photography. The difference between the IE and CU methods of jet generation is found.

The vector fields admitting one-parameter spatial symmetry group and their reduction

For a n-dimensional vector fields preserving some n-form, the following conclusion is reached by the method of Lie group. That is, if it admits an one-parameter, n-form preserving symmetry group, a transformation independent of the vector field is constructed explicitly, which can reduce not only dimesion of the vector field by one, but also make the reduced vector field preserve the corresponding ( n - 1)-form. In partic ular, while n = 3, an important result can be directly got which is given by Me,ie and Wiggins in 1994.

Performance of a small high-speed liquid jet apparatus

The performance of a small high-speed liquid jet apparatus is described. Water jets of 200m/s to 700m/s have been obtained by firing a deformable lead slug from an air rifle into a stainless steel nozzle containing water sealed with a rubber diaphragm. Nozzle devices of using the impact extrusion (IE) method and cumulation (CU) method are designed to generate jets. The injection sequences are visualized using schlieren photography. The difference between the IE and CU methods in the jet generation is found.

Soluble Angiopoietin Receptor Tie-2 In Patients With Acute Myocardial Infarction And Its Detection By Optical Protein-Chip

The Tie-2 receptor has been shown to play a role in angiogenesis in atherosclerosis. The conventional method assaying the level of soluble Tie-2 (sTie-2) was ELISA. However, this method has some disadvantages. The aims of this research are to establish a more simple detection method, the optical protein-chip based on imaging ellipsomtry (OPC-IE) applying to Tie-2 assay. The sTie-2 biosensor surface on silicon wafer was prepared first, and then serum levels of sTie-2 in 38 patients with AMI were measured on admission (day 1), day 2, day 3 and day 7 after onset of chest pain and 41 healthy controls by ELISA and OPC-IE in parallel. Median level of sTie-2 increased significantly in the AMI patients when compared with the controls. Statistics showed there was a significant correlation in sTie-2 results between the two methods (r=0.923, P0.01). The result of this study showed that the level of sTie-2 increased in AMI, and OPC-IE assay was a fast, reliable, and convenient technique to measure sTie-2 in serum.

陆地棉组织培养及转化研究

1．以MS无机盐+B 5有机成分为基本培养基，附加2，4-D，KT，ZT等激素，以农艺性状良好，抗枯萎病的棉花品种“冀492”为材料，建立了愈伤组织诱导，体细胞胚胎发生和植株再生体系． 2．实验结果表明，2，4-D是诱导愈伤组织产生的促进因子，效果明显好于其它生长素类物质，但是随着培养基中2，4-D浓度的升高，愈伤组织状态也会变差，褐化严重，而且，附加O.lppm 2，4-D，O.lppm K T的培养基是较为合适的培养基．IAA，NAA对愈伤组织的诱导不十分理想，此外，愈伤组织的产生还同外植体，基因型和一些物理条件有关， 胚性愈伤组织的产生，需不断调节培养基中激素浓度，逐步降低2，4 -D浓度，并添加低浓度ZT，胚状体要在去除2，4-D的培养基上才能产生．虽然，2，4-D对于胚性愈伤组织的诱导是必须的，但是却抑制胚状体的发育． 3．培养基中硝态氮和氨态氮比例，激素浓度和种类，活性炭的添加，对于胚状体的萌发和成熟有重要影响，硝酸钾加倍，硝酸铵减半，并附加低浓度ABA和活性炭是胚状体诱导和成苗（去除ABA）的适宜培养基，而附加0.2ppm N A A，0.2ppm ZT和活性炭的M S2培养基是胚状体成熟的适宜培养基．通过对胚性愈伤组织的干燥处理，培养基中低浓度ABA和活性炭的添加，比较有效地抑制了畸形胚的产生，大大地提高了正常胚的比例． 4．对陆地棉“冀4 9 2”的下胚轴和子叶利用含Bt抗虫基因的根农杆菌(AgrobacterIIm tumefrens)进行了遗传转化研究，在筛选培养基上获得了大量生长旺盛的阳性愈伤组织，葡糖酸苷检测结果表明，大部分愈伤组织均有G us基因的表达． 5．通过花粉管通道法，进行了将含有Bt抗虫基因DNA的大肠杆菌质粒导入陆地棉“冀492”的实验，并收获了近1 0，000粒种子，为从大量种子中筛选出抗性种质材料，建立了卡那霉素田间初步筛选法． 6．利用活体压片和石蜡切片技术对体细胞胚胎发生过程和胚状体起源进行了观察，发现胚状体发生主要是通过类合子途径进行的，胚状体可能起源于单细胞． 7．通过对相同培养基上的非胚性愈伤组织，胚性愈伤组织和不同时期胚状体的可溶性蛋白SDS - PAGE电泳分析，发现16KD和50K D蛋白特异性地存在于胚性愈伤和各期胚状体中，该蛋白可作为胚性愈伤组织的筛选标记．对不同发育时期的愈伤组织进行了同工酶和可溶性蛋白的IE F/SD S-PA G E双向电泳分析，结果表明，不同发育时期的愈伤组织同工酶酶谱和可溶性蛋白电泳图谱之间具有较大的差别，分化前期的胚性愈伤组织酶的活性强，种类多，并且有新的蛋白斑点的出现，这些都可能与体细胞胚胎发生相关．

Effect of ration on the growth and energy budget of Chinese longsnout catfish, Leiocassis longirostris Gunther

The effect of ration on growth and energy budget of Chinese longsnout catfish was investigated in a growth trial. Fish of initial body weight of 6.5 g were fed at six ration levels (RLs): starvation, 0.8%, 1.6%, 2.4%, 3.2% of body weight per day, and apparent satiation for 8 weeks. Fish were weighed biweekly to adjust feed amount. The results showed that specific growth rate in wet weight, protein and energy increased logarithmically with increased RLs. The relationship of specific growth rate in wet weight (SGRw, % day(-1)) and RL (%) was a decelerating curve: SGRw=-0.62+3.10 Ln(RL+1). The energy budget equation at satiation was: 100 IE=12.94 FE+5.50(ZE+UE)+40.07 HE+41.49 RE, where IE, FE, (ZE+UE), HE, RE are food energy, faecal energy, excretory energy, heat production and recovered energy respectively. Body composition was slightly but significantly affected by ration size except for protein content. The most efficient ration based on the relationship between RL and feed efficiency ratio in energy (FERe) was 1.8% of body weight per day.

Effect of body size on growth and energy budget of Nile tilapia, Oreochromis niloticus

A growth trial was conducted at 30 degrees C to investigate the effect of body size on growth and energy budget of Nile tilapia. The average initial body weights of the four size groups tested were 9.3, 34.1, 80.3 and 172.4 g, respectively. Fish were fed to satiation twice a day with a diet containing 35.6% crude protein. Food consumption (C-max: kJ/day) increased with body size (W: g) according to the relationship: Ln C-max = 1.45 + 0.42 LnW. The final body contents of dry matter, crude protein and ash per unit body weight increased with increasing body size while contents of fat and energy were independent of body size. Specific growth rates of wet weight, dry weight, protein and energy decreased as the fish increased in size. Feed efficiencies in wet weigh, dry weight and crude protein decreased with increasing body size, while that of energy remained unchanged. The proportions of energy intake allocated to the various components (faecal energy, excretory energy, heat production and recovered energy) of the energy budget were not significantly affected by body size, and the average budget was: 100IE-18.5(+/- 1.33)FE + 5.9 (+/- 3.09)(ZE + UE) + 49.3(+/- 3.77)HE + 26.3(+/- 6.23)RE, where IE, FE, (ZE + UE), HE and RE represent gross energy intake, faecal energy, excretory (non-faecal) energy loss, heat production and recovered energy (growth), respectively. It is suggested that the decrease in growth rate in larger fish is mainly due to the decrease in relative food intake. (C) 1997 Elsevier Science B.V.

Energy budget of Nile tilapia (Oreochromis niloticus) in relation to ration size

Nile tilapia weighing 8.29-11.02 g were fed a practical diet at seven ration levels (starvation, 0.5, 1, 2, 3, 4% body weight per day and satiation) twice a day at 30 degrees C. Feed consumption, apparent digestibility, nitrogenous excretion and growth were determined directly, and heat production was calculated by difference of energy budget. The relationship between specific growth rate in wet weight (SGR(w), percentage per day) and ration size (RL, percentage per day) was a decelerating curve described as SGR(w) = 2.98 (1 - e(-0.61(RL-0.43))). The apparent digestibility coefficients for dry matter and protein showed a decreasing pattern with increasing ration while the apparent digestibility coefficient of energy was not significantly affected by ration size. The proportion of gross energy intake lost in nitrogenous excretion tended to decrease with increasing ration. Feed efficiency was highest, and the proportion of gross energy intake channelled to heat production was lowest, at an intermediate ration level (2% per day). The energy budget at the satiation level was: 100IE = 16.9FE + 1.2(ZE + UE) + 62.3HE + 19.6RE, where IE, FE, (ZE + UE), HE and RE represent gross energy intake, faecal energy, excretory (non-faecal) energy loss, heat production and recovered energy (growth), respectively. (C) 1997 Elsevier Science B.V.

Electro-mass olfactory multi-sensor (EMMS)

For an olfactory sensor or electronic nose, the task is not only to detect the object concentration, but also to recognize it. It is well known that all the elements can be identified by their charge to mass ratio e(+)/m. We tried to imitate this principle for molecular recognition. Two kinds of sensors are used simultaneously in testing. One is quartz crystal microbalance (QCM) for detecting the change in mass, the other is interdigital electrode (IE) for detecting the change in conduction, as an electro-mass multi-sensor (EMMS). in this paper, the principle and the feasibility of this method are discussed. The preliminary results on the recognition of alcohol by EMMS coated with lipids are presented. Meanwhile, the multi-sensor can also be used as an instrument for research on some physico-chemistry problems. The change in conduction of coated membrane caused by one absorbed molecule is reported. It is found that when a QCM is coated with membrane, it still obeys the relationship Delta F (frequency change of QCM) = K Delta m (mass change of absorbed substance) and the proportional coefficient, K, depends not only on quartz properties but also on membrane characteristics as well. (C) 2000 Elsevier Science S.A. All rights reserved.

基于图模型的信息检索技术研究及其应用

信息检索与查询是网络用户最常用的网络服务之一。信息检索技术旨在帮助 用户在有限的时间内找到感兴趣的文档。近年来，基于语言模型的信息检索技术 因其良好的性能和较完备的理论基础而吸引了众多研究者。 文档模型和查询模型 的估计是影响语言模型信息检索系统性能的两个重要因素， 针对现有方法存在的 问题，本文从理论和实际应用两个方面开展了研究。主要工作总结如下： 第一、对目前统计语言模型信息检索技术进行了较为全面和深入的综述。从 相关度估计方法、文档模型和查询模型等方面，对目前语言模型信息检索研究工 作进行了分析，并对一些有代表性的工作进行了介绍。讨论了语言模型信息检索 技术在个性化搜索中的应用。最后基于上述研究现状的分析，给出了语言模型信 息检索未来值得研究的几个方向。 第二、提出一种基于局部词图的文档平滑方法。对于每个文档，我们获取这 篇文档最相似的K个文档，使用这K个文档和文档本身建立一个局部文档集L。在 这个局部文档集L上建立一个局部词图：节点为L中的词项，边为两个节点在L中 的同现次数。然后在这个词图上使用类似PageRank的排序方法计算节点的权重， 使用节点的权重估计文档模型。 在3个TREC数据集上的实验结果验证了该方法的 有效性。 第三、提出一种基于图的迭代增强个性化检索算法。利用文档与文档、文档 与词、词与词这三种相互增强关系来计算词的权值和检索结果文档的得分。并根 据词的权值进行查询扩展，根据文档的得分进行查询结果的重排序。通过查询扩 展可以丰富结果文档，并通过重排序把用户关注的个性化文档推荐给用户。实验 结果表明，本文提出的个性化检索算法能够有效地提高检索精度。最后，基于该 算法，我们实现了IE浏览器插件形式的个性化检索工具GBAIR。

Electro-mass multi odor sensor

For an olfactory sensor or electronic nose the task is not only to detect the object concentration, but also to recognize it. It is well known that all the elements can be identified by their charge to mass ratio e+/m. We tried to use this principle for molecular recognition. Two kinds of sensors are used simultaneously in testing. One is Quartz Crystal Microbalance (QCM) for detecting the change in mass, the other is Interdigital Electrode (IE) for detecting the change in conduction. In this paper the principle and the feasibility of this method are reported. The preliminary results on the recognition of alcohols are presented. The multisensor can be used as an instrument for research on material properties and kinetic process as well.

Electro-mass olfactory multi-sensor (EMMS)

For an olfactory sensor or electronic nose, the task is not only to detect the object concentration, but also to recognize it. It is well known that all the elements can be identified by their charge to mass ratio e(+)/m. We tried to imitate this principle for molecular recognition. Two kinds of sensors are used simultaneously in testing. One is quartz crystal microbalance (QCM) for detecting the change in mass, the other is interdigital electrode (IE) for detecting the change in conduction, as an electro-mass multi-sensor (EMMS). in this paper, the principle and the feasibility of this method are discussed. The preliminary results on the recognition of alcohol by EMMS coated with lipids are presented. Meanwhile, the multi-sensor can also be used as an instrument for research on some physico-chemistry problems. The change in conduction of coated membrane caused by one absorbed molecule is reported. It is found that when a QCM is coated with membrane, it still obeys the relationship Delta F (frequency change of QCM) = K Delta m (mass change of absorbed substance) and the proportional coefficient, K, depends not only on quartz properties but also on membrane characteristics as well. (C) 2000 Elsevier Science S.A. All rights reserved.

Detection of avian influenza virus subtype H5 using a biosensor based on imaging ellipsometry

A novel method is reported for the detection of avian influenza virus subtype H5 using a biosensor based on high spatial resolution imaging ellipsometry (IE). Monoclonal antibodies specific to H5 hemagglutinin protein were immobilized on silicon wafers and used to capture virus particles. Resultant changes on the surface of the wafers were visualized directly in gray-scale on an imaging ellipsometry image. This preliminary study has shown that the assay is rapid and specific for the identification of avian influenza virus subtype H5. Compared with lateral-flow immunoassays, this biosensor not only has better sensitivity, but can also simultaneously perform multiplexed tests. These results suggest that this biosensor might be a valuable diagnostic toot for avian influenza virus detection. (c) 2009 Elsevier B.V. All rights reserved.

Quartz crystal microbalance study of the kinetics of surface initiated polymerization

Surface initiated polymerization (SIP) is a valuable tool in synthesizing functional polymer brushes, yet the kinetic understanding of SIP lags behind the development of its application. We apply quartz crystal microbalance (QCM) to address two issues that are not fully addressed yet play a central role in the rational design of functional polymer brushes, namely quantitative determination of the kinetics and the initiator efficiency (IE) of SIP. SIP are monitored online using QCM. Two quantitative frequency-thickness (f-T) relations make the direct determination and comparison of the rate of polymerization possible even for different monomers. Based on the bi-termination model, the kinetics of SIP is simply described by two variables, which are related to two polymerization constants, namely a = 1/(k (p,s,app)-[M][R center dot](0)) and b = k (t,s,app)/(k (p,s,app)[M]). Factors that could alter the kinetics of SIP are studied, including (i) the molecular weight of monomers, (ii) the solvent used, (iii) the initial density of the initiator, (iv) the concentration of monomer, [M], and (v) the catalyst system (ratio among the ingredients, metal, ligands, and additives). The dynamic nature of IE is also described by these two variables, IE = a/(a + bt). Instead of the molecular weight and the polydispersity, we suggest that film thickness, the two kinetic parameters (a and b), and the initial density of the initiator and IE be the parameters that characterize ultra-thin polymer brushes. Besides the kinetics study of SIP, the reported method has many other applications, for example, in the fast screening of catalyst system for SIP and other polymerization systems.