顶部平坦化32通道AWG的设计与研制

根据优化输入端多模干涉器（MMI）结构设计，研制出32通道50GHz通道间隔、顶部平坦化的阵列波导光栅（AWG）器件。该器件的采用6μm×6μm折射率差为0．75％的Si基SiO2埋型波导结构，阵列波导数为130，罗兰圆半径为9419．72μm，相邻阵列波导长度差为128．42μm。测试结果表明

青藏高原东缘青杨（Populus cathayana Rehd.）遗传多样性研究

青杨（Populus cathayana Rehd.）是青杨派杨树的主要树种之一，为我国特有乡土树种，其主要分布区之一是我国的青藏高原，集中分布地带在甘肃省中部及青海省东部，四川省西北部岷江上游和松潘等地区。本研究以青藏高原东缘青杨天然分布区的6个群体143个个体为材料，用AFLP、SSR和叶绿体SSR分子标记分析青杨天然群体的遗传多样性，分析其遗传结构和分化，比较6个群体间遗传多样性的高低和群体间的遗传关系。旨在为青杨基因资源评价、保护与保存、遗传改良策略制定等提供科学理论依据。通过以上研究，得出如下主要研究结果： 1 AFLP分子标记研究结果 采用4对选择性引物对6个青杨天然群体143个个体进行分析，扩增谱带分析共检测到175个位点，其中173个位点表现为多态，多态位点百分率高达98.9%。从整体上表现出较高的遗传多样性，Nei’s基因多样度(h)水平为0.306。从青杨天然群体位点分布来看，有高达20%的位点（32位点）为群体所特有，仅有9.14%的位点（16位点）在所有群体中存在。群体间的遗传分化极大，所有遗传变异中，有48.9%的遗传变异存在于群体间。在个体群丛（Individuals cluster）和主坐标（PCO analysis）分析中，青杨各群体未呈现任何地理模式，Mantel检测也显示各群体间遗传距离与地理距离无明显相关。研究认为，由于地理和空间上大尺度的隔离和地形地貌复杂使得群体间无法进行基因交流，导致群体间遗传分化极大，另外各群体在不同的选择压力下，经历各自独立的进化历程，这些都可能导致群体间遗传距离与地理距离的不相关。 2 SSR分子标记研究结果 在SSR分析中，7个位点在6个青杨天然群体143个个体中共检测到79个等位基因，每位点检测到的等位基因数在5-16之间，平均11.3个，总体上多态位点百分率达100%。平均观察杂合度和期望杂合度分别为0.792和0.802。Hardy-Weinberg平衡检验表明青杨大部分群体都处于非平衡状态，群体大部分位点都是偏离哈迪-温伯格平衡（76.3%），只有23.7%的测验满足哈迪-温伯格平衡。分析青杨天然群体内和群体间的遗传变异，基因分化系数（GST）为0.373，即有62.7%的遗传变异存在群体内，37.3%的遗传变异存在群体间。群体内的遗传变异高于群体间水平。根据各群体遗传距离UPGMA聚类分析，有来自相临分布区、近似气候类型的群体聚在一起的趋势，但Mantel检测反映遗传距离与地理距离间并无明显相关性。 3 cpSSR分子标记研究结果 分析来自青藏高原东缘6个青杨天然群体，所用cpSSR引物中有5对cpSSR引物（CCMP2、CCMP5、SCUO01、SCU03、SCU07）都表现较高的多态性，单个引物检测的片段数都在4以上。5对cpSSR引物共检测片段数26个，组成了12种叶绿体DNA单倍型。各群体的单倍型分布和频率有较大差异，群体单倍型多样性范围为0-0.4926，TS、JZ、PW和SHY群体单倍型多样性高于QHY和LED群体水平。本研究发现，分布在青藏高原东缘的青杨天然群体，群体间不存在共享的单倍型，各群体间存在极大的遗传分化（GST=0.9223）。从青藏高原东缘地区经历的地质历史事件来看，第四纪的冰期气候变迁可能是造成青杨现今遗传结构模式的主要因素之一。根据单倍型在各群体的分布情况，进行青杨群体聚类分析结果，各群体无明显的分组现象，青杨各群体也未呈现任何清晰地理模式。 由于不同分子标记在对群体遗传多样性检测能力与效率上存在差异，所以三种标记检测的青藏高原东缘青杨天然群体遗传多性水平也不尽一致，但在与用同种方法检测其它物种或同一物种不同种源群体比较，三种分子标记方法都揭示了青藏高原东缘青杨天然群体具有中等偏上的遗传多样性水平。结果分析表明，群体间遗传分化极大，这是由于青杨天然群体分布于青藏高原东缘，既有高原又有高山峡谷，由于地理和空间上大尺度的隔离和地形地貌复杂导致了基因流物理上的阻隔。三种分子标记研究结果经Mantel分析检测，遗传距离与地理距离之间都无明显相关性。较为一致的解释是，青杨分布区域地理和空间上大尺度的隔离和和地形地貌复杂导致群体之间不存在均匀扩散现象，另外各群体在不同的选择压力下，经历各自独立的进化历程，这些都可能导致群体间遗传距离与地理距离的不相关。 The wide geographical and climatic distribution of P. cathayana Rehd. indicates that there is a large amount of genetic diversity available, which can be exploited for conservation, breeding programs and afforestation schemes. The results are as follows: 1 Research results of AFLP genetic diversity In present study, genetic diversity was evaluated in the natural populations of P. cathayana originating from southern and eastern edge of the Qinghai-Tibetan Plateau of China by means of AFLP markers. For four primer combinations, a total of 175 bands were obtained, of which 173 (98.9%) were polymorphic. Six natural populations of P. cathayana possessed different levels of genetic diversity, high level of genetic differentiation existed among populations (GST=0.489) of P. cathayana. Individuals cluster and PCO analysis based on Jaccard’s similarity coefficient also showed evident population genetic structure with high level population genetic differentiation. The long evolutionary process coupled with genetic drift within populations, rather than contemporary gene flow, are the major forces shaping genetic structure of P. cathayana populations. Moreover, there is no correspondence between geographical and genetic distances in the populations of P. cathayana, seldom gene exchange among populations and different selection pressures may be the causes. Our finding of different levels of genetic diversity within population and high level of genetic differentiation among populations provided promising condition for further breeding or conservation programs. 2 Research results of SSR genetic diversity In this study, the genetic diversity of P. cathayana was investigated using microsatellite markers. In a total of 150 individuals collected from six natural populations in the southeastern part of the Qinghai-Tibetan Plateau in China, a high level of microsatellite polymorphism was detected. At the seven investigated microsatellite loci, the number of alleles per locus ranged from 5 to 16, with a mean of 11.3, the observed heterozygosities across populations ranged from 0.408 to 0.986, with a mean of 0.792, and the expected heterozygosities across populations ranged from 0.511 to 0.891, with a mean of 0.802. The proportion of genetic differentiation among populations accounted for 37.3% of the whole genetic diversity. The presence of such a high level of genetic diversity could be attributed to the features of the species and the habitats where the sampled populations occur: The southeastern part of the Qinghai-Tibetan Plateau is regarded as the natural distribution and variation center of the genus Populus in China. Variation in environmental conditions and selection pressures in different populations, and topographic dispersal barriers could be factors associated with the high level of genetic differentiation found among populations. The populations possessed significant heterozygosity excesses, which may be due to extensive population mixing at the local scale. The cluster analysis showed that the populations are not strictly grouped according to their geographic distances but the habitat characteristics also influence the divergence pattern. In addition, we suggest that population SHY should be regarded as an ecologically divergent species of P. cathayana. 3 Research results of cpSSR genetic diversity Genetic diversity of six natural populations of P. cathayana originating from the southeastern part of the Qinghai-Tibetan Plateau in China was studied by use of cpSSR markers. Based on 5 pairs of polymorphic primers screened from 12 pairs of primers, twenty-six different length fragments and twelve different kinds of haplotypes were reduced in 143 samples. There were significant variant haplotypes among the populations．There were no shared haplotypes found among populations, analysis of molecular variance indicated that a high proportion of the total genetic variance was attributable to variations among populations (92.23%). The pattern of genetic structure which is associated with spatial separation, variation in environmental conditions and selection pressures in different populations, is also the result of geological historical factor. A molecular phylogenetic tree based on the 12 haplotypes showed that the populations are not strictly grouped according to their geographic distances.

长安四府村32～10kaBP期间沙尘暴活动的记录

IEECAS SKLLQG

由剂量当量率估算52MeV/u~(32)S+Ta的中子与γ光子产额

研究通过测量中子和γ剂量当量率估算 5 2MeV/u32 S束轰击Ta靶时的中子与γ光子产额的方法 ,并给出了估算结果。

白浆土－植物系统营养物质转化机制及其有效性研究Ⅰ．~（32）P同位素示踪法对白浆土中P肥利用率

利用３２Ｐ同位素示踪法对白浆土中Ｐ肥利用率进行了研究．结果表明，在岗地白浆土上，表层土壤表现出一定程度的供Ｐ不足现象，白浆层土壤有效Ｐ含量严重缺乏．表层土壤中当季Ｐ肥利用率的变幅范围为６．０９～１２．３５％，白浆层土壤Ｐ肥利用率为１３％左右．施用有机肥能明显提高白浆土ＯｌｓｅｎＰ的含量，加速土壤本身Ｐ的活化，各种有机物中，以猪粪对土壤潜在Ｐ的活化效果最好．将ＯｌｓｅｎＰ与Ｘ值、Ａ值比较，认为ＯｌｓｅｎＰ是评价白浆上Ｐ肥力简便易行的可靠指标．

A {Co-32} Nanosphere Supported by p-tert-Butylthiacalix[4]arene

Calixarene-capped Co-32 clusters are constructed by a sodalite Co-24(II) cage and an encapsulated Co-8(III) cube. The spherical units are arranged into three isomeric structures, two of which are stacked by the bcc lattices and the third of which is assembled by the cubic closest packing of the spherical units.

The crystal structure and drawing-induced polymorphism in poly(aryl ether ketone)s .1. Poly(oxybiphenyl-4-4'-diyloxy-1,4-phenylenecarbonyl-1,3-phenylenecarbonyl-1,4-phenylene)

Crystal structure and polymorphism induced by uniaxial drawing of a poly(aryl ether ketone) [PEDEKmK] prepared from 1,3-bis(4-fluorobenzoyl)benzene and biphenyl-4,4'-diol have been investigated by means of transmission electron microscopy (TEM), electron diffraction (ED), wide-angle X-ray diffraction (WAXD), and differential scanning calorimetry (DSC) techniques. The melting and recrystallization process in the temperature range of 250-260 degrees C, far below the next melting temperature (306 degrees C), was identified and found to be responsible for the remarkable changes in lamellar morphology. Based on WAXD and ED patterns, it was found that crystal structure of isotropic-crystalline PEDEKmK obtained under different crystallization conditions (melt-crystallization, cold-crystallization, solvent-induced crystallization, melting-recrystallization, and crystallization from solution) keeps the same mode of packing, i.e., a two-chain orthorhombic unit cell with the dimensions a = 0.784 nm, b = 0.600 nm, and c = 4.745 nm (form I). A second crystal modification (form II) can be induced by uniaxial drawing above the glass transition temperature, and always coexists with form I. This form also possesses an orthorhombic unit cell but with different dimensions, i.e., a = 0.470 nm, b = 1.054 nm, c = 5.064 nm. The 0.32 nm longer c-axis of form II as compared with form I is attributed to an overextended chain conformation due to the expansion of ether and ketone bridge bond angles during uniaxial drawing. The temperature dependence of WAXD patterns for the drawn PEDEKmK suggests that form II can be transformed into the more stable form I by relaxation of overextended chains and relief of internal stress at elevated temperature in absence of external tension.

SUPERCONDUCTIVITY IN BI1.5PB0.4SBXSR2CA2CU2OY SYSTEM (X=0-0.32)

The effect of doping with various amount of Sb (0.06-0.32) to (Bi,Pb):Sr:Ca:Cu = 1:1:1:1 system were studied with XRD and Tc measurements. The presence of Sb promotes the conversion of low Tc phase (2212 phase) to high Tc phase (2223 phase) and at around Sb = 0.18 the 2212 phase nearly completely disappears; but at the same time a new phase of unknown structure appears even with Sb = 0.06 showing that the incorporation of Sb into the Bi-based superconducting phase is of very low concentration. Tc measurements show that the optimum concentration of Sb-doping is around 0.10 and that unknown phase has an adverse effect to the superconducting properties; a composition disproportion at the surface of pellet was observed.