两种高Tg非线性光学聚合物母体及掺杂、极化的研究

利用具有非线性光学活性的对硝基苯胺掺杂高玻璃化转变温度的聚芳醚砜(PES-C)和聚芳醚酮(PEK-C),得到了两种掺杂含量较高的掺杂型非线性光学聚合物体系。电晕极化表明较高的取向和较慢的松驰。

细胞色素P-450模拟体系的活性中间体—亚碘酰苯铬(Ⅳ)四苯基卟啉配合物的分离、表征和氧化反应

铬(Ⅲ)四苯基卟啉-亚碘酰苯体系在温和条件下能催化氧化碳氢化合物,是细胞色素P-450很好的模拟体系。分离和表征细胞色素P-450模拟体系的活性中间体,不仅能解释细胞色素P-450模拟体系催化氧化碳氢化合物的反应机理,而且也有助于深入了解细胞色素P-450催化氧化碳氢化合物的反应机理及其活性中间体的结构。我们首先分离和表征的细胞色素P-450模拟体系的一种活性中间体-氧配位铬(V)四苯基卟啉配合物,具有氧化碳氢化合物的活性。这篇论文报道细胞色素P-450模拟体系的另一种活性中间体-亚碘酰苯铬(Ⅳ)四苯基卟啉配合物的分离,表征和对环已烯的氧化性质。

[Cp_2ErCl(THF)]_2的晶体结构

本文报导了(Cp_2ErCl(THF)]_2的晶体结构,晶体属单斜晶系,P2_1/c空间群。晶胞参数为a=8.141(2),b=21.218(6),c=8.597(2),β=107.77(2)°;V=1414.1(6) ~3;Z=2,D_c=1.90g/cm~3,F(000)=780,μ_c=66.3cm~(-1)(MoK_a)。最终的偏离因子R=0.047,R_(to)=0.048。结构分析表明,该配合物是以两个氯离子与金属离子桥联的二聚体形式存在。四氢呋喃中的氧原子同金属离子键合,Er—O键长为2.490(6),两个环戊二烯中的所有碳原子同金属离子间的平均键长为2.649,Er-Cl=2.666(3),Er—Cl-a=2.797(3),Er-Er_a=4.42,Cl-Er-Cl_a键角为72.2°。

OBSERVATION OF MOSSBAUER-EFFECT IN THE HIGH-TEMPERATURE SUPERCONDUCTOR EUBA2CU3O7-X WITH DC ELECTRIC-CURRENT

The difference between the Mossbauer parameters for EuBa2Cu3O7-x with dc electric current and those without dc electric current at 83 K has been observed. The change in isomer shift, electric quadrupole splitting and the asymmetry parameter of the electric field gradient at the Eu-151 nucleus may be caused by the movement of a mass of conduction electrons along a certain direction in the EuBa2Cu3O7-x crystal with a layered structure.

钙钛矿型LnGaO_3(Ln=La、Pr、Nd)晶体的光谱性质

本文报导了室温下钙钛矿型LnGaO_3(Ln=La、Pr、Nb)晶体的紫外、可见和红外吸收光谱的测定,对主要谱带进行了归属。从理论上计算出点阵振动数目和对称类型,并与实验结果进行了对比。晶体的色心及退火对吸收光谱的影响也做了研究。首次得到LaGaO_3和PrGaO_3晶体室温下的激发光谱和荧光光谱,观察到由于晶场环境不同引起荧光谱线窄化的现象。发现LaGaO_3晶体能够产主峰值为540nm的可见荧光,有成为色心发光晶体的可能性。

γ-辐照结晶聚合物的表征——用T_c表征某些聚合物的辐射交联

本工作发现,用DSC测定从熔体等速降温时辐照样品的结晶温度T_c随辐照剂量R增加而线性变低,即辐照前后样品的△T_c=T_c_o-T_c_R=KR。依据Charlesby-Pinner方程,导出一新关系式,S+S~(1/2)=A+B/△T_c。已经证明,式中的T_c只与聚合物的交联度有关,与辐射交联方法和过程无关。因此,该方程可用于结晶聚合物的强化辐射交联,以获得非无规交联的瞬时G(c,1)值。本文为定量研究结晶聚合物的无规交联与非无规交联提供了一个简便的方法。

氢化物发生-分光光度法测定微量铅的研究

本文提出了一个以硝酸银-明胶-乙醇为氢化铅吸收显色液测定微量铅的新的分光光度法。该方法试剂毒性小、操作简便快速、灵敏度较高,氢化铅发生率达87％。用于分析沉积物样品,取得了较好的结果。

Dy~(3+),Sm~(3+)和Ce~(3+)离子在M_3La_2(BO_3)_4(M=Ca,Sr,Ba)中光谱性质的研究

本文报导了Dy~(3+),Sm~(3+)和Ce~(3+)离子在M_3La_2(BO_3)_4(M=Ca,Sr,Ba)基质中的激发与发射光谱;研究了Dy~(3+)离子黄蓝发射的相强度随基质化合物的组成和结构的不同而呈现的变化规律;讨论了Sm~(3+)离子电荷迁移激发带的能量与基质中近邻阳离子的关系并分析了Sm~(3+)和Eu~(3+)离子4f电子构型对电荷迁移带能量的影响。本文还给出了Dy~(3+),Sm~(3+)和Ce~(3+)离子发光的浓度淬灭值。

裂解气相色谱法讲座Ⅱ 裂解器

裂解装置是裂解色谱仪的关键部件,它包括裂解器、连接管和控制部分。习惯上为了简便起见,就把裂解装置称作裂解器。在概述中已经指出,影响裂解反应的因素,除了样品本身外,主要有温度,裂解器的结构和性能等。从五十年代建立裂解色谱法以来,人们研制了各种形式的裂解器,其中主要有四种类型,即热丝(带)、管式炉、居里点和激光。从加热方式来看,除管式炉为连续式外,其余三种均为脉冲式。两者之间的差别在于:前者为裂解室的平衡温度是预先设置和控制好的,随后把样品架推入裂解室样品裂解;后者是使裂解室荷载样品的发热元件(或样品架)在瞬间(或短

Construction of bacterial artificial chromosome libraries for Zhikong Scallop Chlamys farreri

Two Large-insert genomic bacterial artificial chromosome (BAC) libraries of Zhikong scallop Chlamys farreri were constructed to promote our genetic and genomic research. High-quality megabase-sized DNA was isolated from the adductor muscle of the scallop and partially digested by BamH I and Mbo I, respectively. The BamH I library consisted of 53 760 clones while the Mbo I library consisted of 7 680clones. Approximately 96 % of the clones in BamH I library contained nuclear DNA inserts in average size of 100 kb, providing a coverage of 5.3 haploid genome equivalents. Similarly, the Mbo I library with an average insert of 145 kb and no insert-empty clones, thus providing a genome coverage of 1.1 haploid genome equivalents.

There are two 5 '-flanking regions of bkt encoding beta-carotene ketolase in Haematococcus pluvialis

The unicellular green alga Haematococcus pluvialis accumulates a commercially valuable astaxanthin, with levels reaching up to 4% dry weight under environmental stress. In recent years, much effort has been devoted to understanding the molecular mechanisms regulating astaxanthin biosynthetic pathways. Beta-carotene ketolase (bkt), with control being exhibited at the transcription level, plays an important role in astaxanthin biosynthesis by H. pluvialis. Here we demonstrate the presence of two separate 5'-flanking regions [1.5 kilobase (kb) and 2 kb] of bkt (bkt1 and bkt2) that possess regulatory elements similar to those of known stress-responsive genes in plants. Results of 5'-deletion constructs and transient beta-galactosidase expression assays demonstrate that there may be positive regulatory elements governing expression in the shorter promoter at -1060/-900 from the 1.5 kb 5' region, and in the longer promoter at -1838/-1219 and at -1046/ -734 from the 2 kb 5' region relative to each homologous ATG start codon. Furthermore, our present studies reveal that the first intron (+371/+497) downstream from the 1.5 kb 5' untranslated region of bkt1 may function as a negative regulatory element to regulate its own promoter.

The Shandong mud wedge and post-glacial sediment accumulation in the Yellow Sea

Two well-defined deltaic sequences in the Bohai Sea and in the South Yellow Sea represent post-glacial accumulation of Yellow River-derived sediments. Another prominent depocenter on this epicontinental shelf, a pronounced clinoform in the North Yellow Sea, wraps around the northeastern and southeastern end of the Shandong Peninsula, extending into the South Yellow Sea. This Shandong mud wedge is 20 to 40 m thick and contains an estimated 300 km(3) of sediment. Radiocarbon dating, shallow seismic profiles, and regional sea-level history suggest that the mud wedge formed when the rate of post-glacial sea-level rise slackened and the summer monsoon intensified, at about 11 ka. Geomorphic configuration and mineralogical data indicate that present-day sediment deposited on the Shandong mud wedge comes not only from the Yellow River but also from coastal erosion and local rivers. Basin-wide circulation in the North Yellow Sea may transport and redistribute fine sediments into and out of the mud wedge.

Reconstruction of vertical thermal structure from several subsurface temperatures in the China Seas and adjacent waters

Empirical Orthogonal Function (EOF) analysis is used in this study to generate main eigenvector fields of historical temperature for the China Seas (here referring to Chinese marine territories) and adjacent waters from 1930 to 2002 (510 143 profiles). A good temperature profile is reconstructed based on several subsurface in situ temperature observations and the thermocline was estimated using the model. The results show that: 1) For the study area, the former four principal components can explain 95% of the overall variance, and the vertical distribution of temperature is most stable using the in situ temperature observations near the surface. 2) The model verifications based on the observed CTD data from the East China Sea (ECS), South China Sea (SCS) and the areas around Taiwan Island show that the reconstructed profiles have high correlation with the observed ones with the confidence level > 95%, especially to describe the characteristics of the thermocline well. The average errors between the reconstructed and observed profiles in these three areas are 0.69A degrees C, 0.52A degrees C and 1.18A degrees C respectively. It also shows the model RMS error is less than or close to the climatological error. The statistical model can be used to well estimate the temperature profile vertical structure. 3) Comparing the thermocline characteristics between the reconstructed and observed profiles, the results in the ECS show that the average absolute errors are 1.5m, 1.4 m and 0.17A degrees C/m, and the average relative errors are 24.7%, 8.9% and 22.6% for the upper, lower thermocline boundaries and the gradient, respectively. Although the relative errors are obvious, the absolute error is small. In the SCS, the average absolute errors are 4.1 m, 27.7 m and 0.007A degrees C/m, and the average relative errors are 16.1%, 16.8% and 9.5% for the upper, lower thermocline boundaries and the gradient, respectively. The average relative errors are all < 20%. Although the average absolute error of the lower thermocline boundary is considerable, but contrast to the spatial scale of average depth of the lower thermocline boundary (165 m), the average relative error is small (16.8%). Therefore the model can be used to well estimate the thermocline.

渤海湾和胶州湾表层沉积物中甾醇的分布和来源

甾醇及其成岩作用过程中生成的衍生物普遍存在于沉积物中，由于该类化合物的特定来源及其分子结构中的不同特征结构反应了在不同生物体体内合成过程的差异，因此常将其作为一类重要的生物化学标志物用于指示与许多海洋及陆 地生物有关的有机物质的来源和输入，以及用于生物地球化学的研究和环境质量及环境污染的评价。该类化合物在近海环境中已得到广泛应用，然而对中国北部陆海相互作用强烈，受人类活动影响显著的近海沉积物中甾醇的研究尚未见报道。 本研究以渤海湾和胶州湾为目标，系统研究了甾醇类化合物在渤海湾和胶州湾22 个表层沉积物样品中含量和组成，并分析了其分布特征和来源。 通过测定沉积物有机物C/N 比值，表明渤海湾和胶州湾 两海区沉积物中的有机物主要来自陆源植物和人为源的输入。所测定的8 种甾醇类化合物在两海区表层沉积物中的含量和分布具有很大的区域差异，其浓度范围在0~4.303 μg/g，渤海湾甾醇总浓度为0.287~18.579 μg/g，高于胶州湾0.084~10.584 μg/g。8种化合物中只有谷甾醇在全部样品中检出，而粪便甾醇仅存在于受人类活动影响较大和有生活污水输入的近岸区域。而代表陆源高等植物来源的特征甾醇化合物豆甾醇和谷甾醇则在河口区表层沉积物中分布较高。研究表明根据表层沉积物中不同甾醇化合物的组成、含量和分布特征，可以很好地指示河流输入以及大量生活废水的排放对近岸海区的污染状况, 从而可以作为近岸环境污染监测和评价的重要指标。