Pt／C－SPE和PtRu／C－SPE膜电极上甲醇的催化氧化

采用化学还原法制得直接甲醇燃料电池中甲醇阳极氧化的Ｐｔ／Ｃ和ＰｔＲｕ／Ｃ催化剂．结果表明后者比前者具有更高的催化活性．通过ＸＲＤ和ＸＰＳ的分析，阐明了Ｒｕ对提高甲醇电催化氧化活性的作用．

4f金属化合物催化苯乙烯和双烯烃的共聚 Ⅱ．苯乙烯和丁二烯共聚合的研究

用新型稀土催化体系Ｌ３ＬｎｎＬ＇－ＲＸ－Ｒｍ＇ＡＩＨ３－ｍ对苯乙烯和丁二烯共聚合反应进行了系统地研究．探讨了配位基因、稀土元素、烷基铝和第三组份等因素对共聚合反应活性、聚合物的分子量以及立体规整性的影响．用１３Ｃ—ＮＭＲ方法解析了共聚物的序列结构．计算了苯乙烯与丁二烯的三种微现结构的键接几率，并以π－烯丙基机理和近扣配位机理，对一些实验结果进行了定性的解释．

麝鼠香化学成分的研究

对麝鼠香腺分泌物的一般化学成分和有效成分进行了分析测定，结呆表明，分泌物约由１１％水分、３．５％粗蛋白质、８５．５％粗脂肪、０．７％灰分所组成。主要有效成分为麝香酮和环十七烷酮。

以AQ膜中沉积铂的玻碳电极为基底的葡萄糖传感器

生物传感器所面临的两个主要问题就是电活性物质对测定的干扰和生物样品中大分子物质对电极的污染.人们很早就在研究解决这两个问题的方法.使用透析膜可以一定程度地解决上述问题,但这种传感器的响应时间太长.从80年代起,人们开始研究使用化学修饰电极来解决干扰和污染的问题,先后研制了以醋酸纤维素膜、聚邻苯二胺膜、Nation 膜修饰电极为基底的葡萄糖传感器.Eastman AQ 是一种全氟代磺酯,具有阳离子交换性质,易溶于水,而干燥后不再溶于水.利用这个性质,J.Wang 用 AQ-55在铂电极表面用一步法固定了葡萄糖氧化酶,在+0.7V(vs.Ag/Ag-Cl)下.AQ 膜可以使干扰低到最小的程度.Hale等在碳糊葡萄糖氧化酶电极表面涂一层 AQ-29D 膜,用来消除干扰和防止酶的流失.

INVESTIGATION OF ELECTRIC DICHROISM OF CETYLPYRIDINIUM BROMIDE BY SPECTROELECTROCHEMISTRY WITH A LONG OPTICAL-PATH LENGTH THIN-LAYER CELL

In this paper, the electric dichroism of cetylpyridinium bromide (CPB) has been found and studied by spectroelectrochemistry with a long optical path length thin-layer cell (LOPTLC) for the first time. The CPB molecule with a long carbon chain and a polar pyridinium ring is anisotropic in molecular configuration or in polarizability. In the electric field of a thin-layer cell, the CPB molecule reorientates along the direction of the electric field and exhibits electric dichroism, which results in the increase of absorbance of CPB in the UV-vis range. By use of in situ measurement of spectroelectrochemistry, the order parameters of long molecular axis (S = 0.845) and short molecular axis (D = 0.155) and the angle between the long axis direction of the CPB molecule and the direction normal to the electrode surface (theta = 18-degrees 44') have been determined. These data were used to describe the state of arrangement of the molecules in the solution. The reorientation of CPB molecules is the result of the interaction between the anisotropic molecules and electric field. The effects of the concentration of CPB and of the applied electric field on the electric dichroism have been investigated.

星形聚苯乙烯本体粘弹性对结构的依赖性

用应力松弛法研完了一组4—12支链星形聚苯乙烯本体的粘弹性。从应力松弛主曲线测定了零切变粘度η_0、稳态柔量J_e~o和其它流变学参数。结果发现,零切变粘度和最大松弛时间τ_m强烈地依赖于聚合物的分子尺寸,并且可以用无扰特性粘度或折合分子量来描述。η_0和τ_m随支化度增大而增大。实验还直接证实了支链长度相同的星形聚合物的J_e~o与支链数目无关,但是星形聚合物的稳态柔量比具有和支链间分子量相同的线形聚合物的稳态柔量大。

蓖麻油聚氨酯基网状聚合物的动态力学性质

研究了蓖麻油聚氨酯基AB型交联聚合物(ABCP)及同步法合成互穿聚合物网络(IPN)的动态力学谱。ABCP的两组分近似互容,在动态力学谱上呈现出单一T_g松弛,用透射电子显微镜观察,聚氨酯相区尺寸小于 2 nm;而其化学组成相同的 IPN则呈现出两相结构,其动态力学谱上有两个 T_g松弛,两组分间虽有链段互穿,但其相容性仍次于 ABCP。

Consensus scoring for enriching near-native structures from protein-protein docking decoys

The identification of near native protein-protein complexes among a set of decoys remains highly challenging. A stategy for improving the success rate of near native detection is to enrich near native docking decoys in a small number of top ranked decoys. Recently, we found that a combination of three scoring functions (energy, conservation, and interface propensity) can predict the location of binding interface regions with reasonable accuracy. Here, these three scoring functions are modified and combined into a consensus scoring function called ENDES for enriching near native docking decoys. We found that all individual scores result in enrichment for the majority of 28 targets in ZDOCK2.3 decoy set and the 22 targets in Benchmark 2.0. Among the three scores, the interface propensity score yields the highest enrichment in both sets of protein complexes. When these scores are combined into the ENDES consensus score, a significant increase in enrichment of near-native structures is found. For example, when 2000 dock decoys are reduced to 200 decoys by ENDES, the fraction of near-native structures in docking decoys increases by a factor of about six in average. ENDES was implemented into a computer program that is available for download at http://sparks.informatics.iupui.edu.

Molecular characterization and mRNA transcript profile of vitellogenin in Chinese shrimp, Fenneropenaeus chinensis

A full-length cDNA encoding vitellogenin (Vg) was cloned from Chinese shrimp, Fenneropenaeus chinensis using RACE method. The full-length cDNA consist of 7,942 nucleotides including a 7,761 bp open reading frame, which encodes 2,587 amino acid residues. The deduced amino acid sequence showed high (from 94% to 37%) identity with other known crustacean Vgs. In addition, a consensus cleavage site (R-X-K/R-R) recognized by an endopeptidase and a member of subtilisin family of serine protease were identified in the deduced Vg precursor. RT-PCR analysis shown that Vg mRNA can be detected in both ovary and hepatopancreas of vitellogenic females but not in other experimental tissues including muscle, heart, lymph organ, gill, haemocytes and intestine. These results suggest that the Vg gene may be expressed exclusively in mature females, and both ovary and hepatopancreas are the possible tissues for Vg synthesis in F. chinensis. In addition, Vg gene is detected in genomic DNA of both females and males.

Numerical wave flume study on wave motion around submerged plates

Nonlinear interaction between surface waves and a submerged horizontal plate is investigated in the absorbed numerical wave flume developed based on the volume of fluid (VOF) method. The governing equations of the numerical model are the continuity equation and the Reynolds-Averaged Navier-Stokes (RANS) equations with the k-epsilon turbulence equations. Incident waves are generated by an absorbing wave-maker that eliminates the waves reflected from structures. Results are obtained for a range of parameters, with consideration of the condition under which the reflection coefficient becomes maximal and the transmission coefficient minimal. Wave breaking over the plate, vortex shedding downwave, and pulsating flow below the plate are observed. Time-averaged hydrodynamic force reveals a negative drift force. All these characteristics provide a reference for construction of submerged plate breakwaters.

Ship-board measurements and estimations of air-sea fluxes in the western tropical Pacific during TOGA COARE

Direct air-sea flux measurements were made on RN Kexue #1 at 40 degrees S, 156 degrees E during the Tropical Ocean Global Atmosphere (TOGA) Coupled Ocean-Atmospheric Response Experiment (COARE) Intensive Observation Period (IOP). An array of six accelerometers was used to measure the motion of the anchored ship, and a sonic anemometer and Lyman-alpha hygrometer were used to measure the turbulent wind vector and specific humidity. The contamination of the turbulent wind components by ship motion was largely removed by an improvement of a procedure due to Shao based on the acceleration signals. The scheme of the wind correction for ship motion is briefly outlined. Results are presented from data for the best wind direction relative to the ship to minimize flow distortion effects. Both the time series and the power spectra of the sonic-measured wind components show swell-induced ship motion contamination, which is largely removed by the accelerometer correction scheme, There was less contamination in the longitudinal wind component than in the vertical and transverse components. The spectral characteristics of the surface-layer turbulence properties are compared with those from previous land and ocean results, Momentum and latent heat fluxes were calculated by eddy correlation and compared to those estimated by the inertial dissipation method and the TOGA COARE bulk formula. The estimations of wind stress determined by eddy correlation are smaller than those from the TOGA COARE bulk formula, especially for higher wind speeds, while those from the bulk formula and inertial dissipation technique are generally in agreement. The estimations of latent heal flux from the three different methods are in reasonable agreement. The effect of the correction for ship motion on latent heat fluxes is not as large as on momentum fluxes.

Determination of tetrodotoxin by liquid chromatography coupled with electrospray ion-trap mass spectrometry

Two methods for tetrodotoxin analysis using liquid chromatography coupled with electrospray iontrap mass spectrometry (LC-ESI-MS) have been established with C,, reversed phase column and hydrophilic interaction liquid chromatography (HILIC) column, respectively. Sensitivity and reproducibility of the methods were compared. The method using C-18 column in selected ion monitoring (SIM) mode had a detection limit (S/N = 3) of 120 pg, and a good linearity of the calibration curve was obtained for tetrodotoxin (r = 0. 9992). High reproducibility of the method was observed, with a relative standard deviation (RSD) below 10%. The method using HILIC column in SIM mode and selected reaction monitoring (SRM) mode had detection limits (S/N = 3) of 15 and 3.75 pg, respectively. Good linearity of the calibration curves was obtained for tetrodotoxin (r = 0. 9996 and 0. 9998 in SIM and SRM mode, respectively). T he reproducibility was high in SIM mode but relatively poor in SRM mode. Based on the results, the method using HILIC column in SIM mode was suggested for the analysis of tetrodotoxin with LC-MS system.

A preliminary genetic linkage map of the pacific abalone Haliotis discus hannai Ino

Preliminary genetic linkage maps were constructed for the Pacific abalone (Haliotis discus hannai Ino) using amplified fragment length polymorphism (AFLP), randomly amplified polymorphic DNA (RAPD), and microsatellite markers segregating in a F, family. Nine microsatellite loci, 41 RAPD, and 2688 AFLP markers were genotyped in the parents and 86 progeny of the mapping family. Among the 2738 markers, 384 (including 365 AFLP markers, 10 RAPD markers, and 9 microsatellite loci) were polymorphic and segregated in one or both parents: 241 in the female and 146 in the male. The majority of these markers, 232 in the female and 134 in the male, segregated according to the expected 1:1 Mendelian ratio (alpha = 0.05). Two genetic linkage maps were constructed using markers segregating in the female or the male parent. The female framework map consisted of 119 markers in 22 linkage groups, covering 1773.6 cM with an average intermarker space of 18.3 cM. The male framework map contained 94 markers in 19 linkage groups, spanning 1365.9 cM with an average intermarker space of 18.2 cM. The sex determination locus was mapped to the male map but not to the female map, suggesting a XY-male determination mechanism. Distorted markers showing excess of homozygotes were mapped in clusters, probably because of their linkage to a gene that is incompatible between two parental populations.

放牧强度对混播草地群落数量特征的影响

放牧强度对人工草地群落数量特征的影响，国内外学者已有报道，而有关青藏高原的研究则很少。Reategui认为，载畜量增大将使丛生禾草向矮生禾草演替，而导致草地退化。另外，放牧强度对植物群落组成和生物多样性也有很大影响，随着放牧强度的增加，一些适口性高、再生性强、不耐牧的种类减少，而适口性差、耐牧的种类增多。