84.5MeV~(12)C~(4+)离子诱发金属靶原子发射的Kβ与Kα-X射线强度比值的研究

本实验是在中国科学院兰州近代物理研究所,国家实验室的重离子加速器上完成的.实验用OR-TEC公司生产的HPGe X射线探测器测量了84.5 MeV的12C4+离子轰击Cu,Mo,Ag,Cd,In,Sn,W和Au金属靶产生的K壳层特征X射线谱,计算了Kβ与Kα-X射线强度的比值,并将结果与Scofield用Hartree-Fock-Slater模型计算出的理论值与用其它方法(如:衰变幅射,用光子,电子,质子等粒子与靶相互作用)得到的实验值进行了比较.比较结果表明用84.5 MeV的12C4+离子轰击Cu,Mo,Ag,Cd,In,Sn,W和Au金属靶产生的Kβ与K-αX射线强度比值比理论值和其它实验值要大许多.

Environmental geochemistry and health of fluorine in Chinese coals

IEECAS SKLLQG

The effect of the scalar-isovector meson field on hyperon-rich neutron star matter

We investigate the effect of the calar-isovector delta-meson field on the equation of state (EOS) and composition of hyperonic neutron star matter, and the properties of hyperonic neutron stars within the frame work of the relativistic mean field theory. The influence of the delta-field turns out to be quite different and generally weaker for hyperonic neutron star matter as compared to that for npe mu neutron star matter. We find that inclusion of the delta-field enhances the strangeness content slightly and consequently moderately softens the EOS of neutron star matter in its hyperonic phase. As for the composition of hyperonic star matter, the effect of the delta-field is shown to shift the onset of the negatively-charged (positively-charged) hyperons to slightly lower (higher) densities and to enhance (reduce) their abundances. The influence of the delta-field on the maximum mass of hyperonic neutron stars is found to be fairly weak, where as inclusion of the delta-field turns out to enhance sizably both the radii and the moments of inertia of neutron stars with given masses. It is also shown that the effects of the delta-field on the properties of hyperonic neutron stars remain similar in the case of switching off the Sigma hyperons.

基于FPGA的CSR高频控制系统相位求解模块设计

CSR高频控制系统需要对高频正弦波激励信号的幅度、相位、频率进行稳定控制。相位arctan(Q/I)求解是必不可少的模块。论述了一种新的基于FPGA平台和对称查找表法(SBTM)的求解相位arctan(Q/I)的方法,做了详细的理论分析,给出了具体实现的代码和结果。该模块精度高,消耗资源少,可直接应用于CSR高频控制系统。

大气沉降核素~(7)Be在黄土高原地被物中的分布初探

7Be具有环境微粒示踪价值,在示踪土壤侵蚀研究中有一定的应用,但是有关地被覆盖物对7Be截留吸收的研究目前还相当少,这直接影响了示踪结果的准确性、示踪模型的建立及应用。本文对不同地被物中的7Be含量进行了分析,结果表明:春季末地表不同地被覆盖物中干枯植物的7Be含量最大,半分解物次之,活植物中含量最少。在整个植物生长期内,植物体7Be累积含量呈增长趋势,尤其在秋季增加更为突出;不同植物中7Be含量差异性很大,变异系数达0.6;从总体上看,不同类型植物中7Be的平均含量分布趋势是草本>半灌木及小灌木>种植作物;和其它同类植物种相比,不同作物种中7Be含量的变异系数相对较大,为0.47。

有机肥用量对玉米体内养分浓度及分配的影响

通过5年(2002~2006年)的田间定位试验,研究了不同施肥量处理对玉米体内养分浓度、养分分配及每形成单位籽实产量收获养分量的影响。结果表明:施有机肥具有稳产高产作用,随着有机肥施用量的增加,玉米的稳产作用更为明显;玉米籽实的氮素和磷素浓度均随有机肥用量的增加而增加,钾素浓度与有机肥用量未呈现出明显相关性,玉米秸秆中的养分浓度大体上随有机肥用量的增加而增加;玉米收获产品中氮、磷含量在籽实和秸秆中的分配比与产量均呈现较好的相关性,钾表现不明显;玉米生长愈好(施肥愈多),每形成单位经济产量消耗的氮、磷、钾就愈多,说明玉米对氮、磷、钾的利用都存在一定程度奢侈吸收。

有机物料及其配施在潮土中的残留特点

试验采用尼龙布袋埋袋法研究了5种单一物料(玉米秸、稻秸、苜蓿、鸡粪、猪粪)和2种混合物料(玉米秸-猪粪-鸡粪、苜蓿-猪粪-鸡粪)在潮土中的腐解状况,以了解土壤中有机质的积累规律,探讨有机肥料对土壤的培肥效果。研究结果表明,玉米秸、稻秸、苜蓿、鸡粪、猪粪等是增加土壤有机质的较好物料;对C/N比较高的物料,当增加N素(添加猪粪、鸡粪这些氮含量较高的物料)、调节C/N比值时,可以促进混合物料有机碳的分解和向腐殖质的转化。

The Study of Electroactive Block Copolymer Containing Aniline Pentamer Isolated from Different Solvents

For the films and powder of polymers containing conductive oligomer are usually obtained from solution, the choice of better solvents for the regular arrangement of oligomers is very important for the higher conductivity. Because of the poor solubility of the oligomers, it is difficult to study the arrangement directly in most common solvents, so, we synthesized a triblock copolymer, mPEG2k-aniline pentamer-mPEG2k, as the model to investigate the arrangement-solvent relationship. For the poor solubility of the AP block in common solvents, the copolymer self-assembled into spheric micelles in toluene and into lamellar crystals in water and THF. The crystallinity (X-c) and crystallization temperature (T-c) values of mPEG blocks in powders prepared from different solvents differed obviously, which may be the effect of different self-assembled structures. From the two-phase model of one-dimensional electron density correlation function of SAXS, the long period of copolymer prepared from THF was presumably equal to the long period of pure mPEG plus the chain length of AP, which demonstrates that the AP blocks arrange regularly in the noncrystalline regions.

A new series of Ru(II)polypyridine surfactants: Synthesis, 2D NMR, fluorescence, electrochemistry and electrochemiluminescence

A new series of Ru(II) polypyridine surfactants, Ru(bpy)(2)[phenNH CO(CH2)(n)CH3](PF6)(2), where n is 10, 12, 14 or 16, has been prepared and characterized. The H-1-NMR spectra of these new Ru(II) complexes were attributed and discussed by the H-1-H-1 COSY method. The comparative analysis of IR spectra of these complexes and their responding free ligands has shown that there are intensive d --> pi* feedback interactions between central Ru(II) and their ligands. Their fluorescent, electrochemical and electrochemiluminescent behaviours are also reported.

Peptidoglycan recognition protein of Chlamys farreri (CfPGRP-S1) mediates immune defenses against bacterial infection

Peptidoglycan recognition protein (PGRP) is an essential molecule in innate immunity for both invertebrates and vertebrates, owing to its prominent ability in detecting and eliminating the invading bacteria. Several PGRPs have been identified from mollusk, but their functions and the underlined mechanism are still unclear. In the present study, the mRNA expression profiles, location, and possible functions of PGRP-S1 from Zhikong scallop Chlamys farreri (CfPG RP-St) were analyzed. The CfPGRP-S1 protein located in the mantle, gill, kidney and gonad of the scallops. Its mRNA expression in hemocytes was up-regulated extremely after PGN stimulation (P < 0.01), while moderately after the stimulations of LPS (P < 0.01) and beta-glucan (P < 0.05). The recombinant protein of CfPGRP-S1 (designated as rCfPGRP-S1) exhibited high affinity to PGN and moderate affinity to LPS, but it did not bind beta-glucan. Meanwhile, rCfPGRP-S1 also exhibited strong agglutination activity to Gram-positive bacteria Micrococcus luteus and Bacillus subtilis and weak activity to Gram-negative bacteria Escherichia coli. More importantly, rCfPGRP-S1 functioned as a bactericidal amidase to degrade PGN and strongly inhibit the growth of E. coli and Staphyloccocus aureus in the presence of Zn2+. These results indicated that CfPGRP-S1 could not only serve as a pattern recognition receptor recognizing bacterial PGN and LPS, but also function as a scavenger involved in eliminating response against the invaders. (C) 2010 Elsevier Ltd. All rights reserved.

Molecular authentication of the traditional Tibetan medicinal plant Swertia mussotii

Swertia mussotii is an important species in Tibetan folk medicine. However, it is quite expensive and frequently adulterated, so reliable methods for authentication of putative specimens and preparations of the species are needed to protect consumers and to support conservation measures. We show here that the chloroplast (cp) DNA rpl16 intron has limited utility for differentiating S. mussotii from closely related species, since the cpDNA rpl16 sequences are identical in S. mussotii and two other species of Swertia. However, the rDNA internal transcribed spacer (ITS) sequences differ significantly between S. mussotii and all of 13 tested potential adulterants. Thus, the ITS region provides a robust molecular marker for differentiating the medicinal S. mussotii from related adulterants. Therefore, a pair of allele-specific diagnostic primers based on the divergent ITS region was designed to distinguish S. mussotii from the other species. Authentication by allele-specific diagnostic PCR using these primers is convenient, effective and both simpler and less time-consuming than sequencing the ITS region.

大规模多数据库系统的互操作机制

Sharing data among disparate databases has so far mostly been achieved through some form of ad-hoc schema integration. This approach becomes less tractable as the number of participating database increases. In this paper,we first present the primary problems to be resolved in large multidatabase systems and discuss the autonomy and heteroheneity of large multidatabase systems and then describe a coalition agent mechanism to implement large multidatabase systems interoperation.

Credit and Debt in medieval England, c.1180-c.1350

Schofield, Phillipp, and N. J. Mayhew, eds., Credit and Debt in medieval England, c.1180-c.1350 (Oxford: Oxbow Books, 2002), pp.x+164 RAE2008