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41.
如何以汉字拼音正确表达我国论作人名的问题非常重要。国家语委过去制定的几个相关件颁布以后,中国人姓名的拼写有了规矩,但仍不能适应献录和计算机信息检索的要求。为了规范数据库中重要检索和评价项目的数据格式,提高检索和数据处理的效率,我们制订了《中国学术期刊(光盘版)检索与评价数据规范(试行)》。该规范对汉语姓名拼写法作了变通处理。执行以来已取得了巨大的成绩。建议国家语言字工作委员会采取措施,尽快对原国家标准做出适当修订。  相似文献   
42.
The enrichment mechanisms of precious metals by base metals or their mattes in pyrometallurgical processes are discussed at the atomic level in this paper. The reasons brought forward for a trace amount of precious metals to be trapped into base metals or mattes are that the melted slag phases possess different chemical structures and properties from that of the melted base metal or matte phases. As for the melted slag phase, its formation is thought to depend on the covalent bonds and the ionic bonds between Si, O atoms and Ca2+, Mg2+, Fe2+ ions to tie up each other. Because the bridging electrons in the slag phase are all thought as the localized electrons, the precious metal atoms are not stable among them. However, as for the metal phase, its formation is thought depend on the metal bonds to bind up the metal atoms. Because the electrons in the metal phases can move freely among the atoms, the precious metal atoms that enter the metal phase can cause the system’s free energy to decrease. For the melted mattes phase,because it has high electrical conductivities (between 103~104 s·cm-1) at higher temperatures, and its temperature coefficients presents the negative values, its conductance mechanism belongs with the electronic conduction. The property of the mattes is in fact similar to that of the metal at their melted state, so the precious metal atoms will enter the matte phase instead of the slag phase in a mattesmelting process.  相似文献   
43.
The effects of zinc(Zn) at different spray concentrations(0, 500, and 1 0001μmol L) on the plant growth, the activities of antioxidant enzymes chemical forms of cadmium(Cd), and the accumulation of Cd were studied and compared between two varieties, Shijichaotianjiao(SJCTJ) and Yanjiao425(YJ425) of pepper(Capsicum annuum L.) in Cd-contaminated soil(Cd 10 1mg kg). The activities of catalase(CAT) and peroxidase(POD) were generally enhanced by Zn. However, superoxide dismutase(SOD) decreased. Addition of Zn decreased the ethanol-extractable Cd, NaCl-extractable Cd, and acetic acid-extractable Cd in the fruit by 34.6%- 55.3%, 2.0%-17.7% and 0.4%-32.9%, and reduced the accumulation of Cd in fruit and plant total Cd by 12.8%- 68.6% and 9.0%-29.3% in both varieties, respectively.  相似文献   
44.
The DBSA-PANI-Fe composite powder with 50wt% of Fe nanoparticles was prepared by mechanically mixing the DBSA-doped polyaniline powder and Fe nanoparticles. The composite powder was compacted to pellets and the pellets were annealed in vacuum at 443,493,543, and 593 K for 60 and 120 min. The conductivity of the pellet increases markedly with increasing the annealing temperature up to 493 K, and then decreases with further increasing the annealing temperature. When the pellet was annealed at 493 K for 60 min, the increment of conductivity reaches a maximum value, and the conductivity is 2.6 times as large as that of the pellet unannealed. The conductivities of the pellets annealed under the conditions of 543 K/120 min, 593 K/60 min, and 593 K/120 min are lower than the conductivity of the pellet unannealed. For all the pellets, the variation in conductivity with temperature reveals that the charge transport mechanism can be considered to be 1-D variable-range-hopping (1-D VRH). The composite pellet shows a magnetic hysteresis loop independent of the annealing condition. The saturation magnetization is about 5.4×104 emu/kg. The saturation field and the coercivity are estimated to be 4.38×105 and 3.06×104 A/m, respectively. The crystalline structure ofFe nanoparticles in the composites does not change with the annealing condition. The annealing condition cannot destroy the polymer backbones.  相似文献   
45.
Iodine-involved single-electron halogen bonds (SEXBs) weak interactions in the systems of CH3···I-Y(Y = BH2, H, CH3, CH==CH2, C≡CH, CN, NC) were investigated for the first time using B3LYP/6-311++G(d,p) and MP2/aug-cc-pVTZ computational levels (the relativistic effective core potential basis set of Lanl2dz was used on iodine atom). The interaction energies between two moieties with basis set super-position error corrections for the seven complexes are -0.57, -1.36, -3.80, -2.17, -4.49,-6.33 and -8.64 kJ mol-1 (MP2/aug-cc-pVTZ ), respectively, which shows that SEXBs interactions are all weak. Natural bond orbital theory analysis revealed that charges flow from CH3 to the I-Y moiety. The total amount of natural bond orbital charge transfer (ΔNC) from the CH3 radical to I-Y increases in the order CH3…IBH2 < CH3…IH ≈ CH3…ICH3 ≈ CH3···IC2H3 < CH3…ICCH< CH3…ICN< CH3…INC. Atoms-in-molecules theory was used to investigate the topological properties of the bond critical points in the seven SEXB structures.  相似文献   
46.
Base isolation is one of the most promising alternatives among the structure control methods. In recent decades, base isolation has been seriously considered for civil structures, such as buildings and bridges, subjected to ground motion. The research achievements and development of seismic base isolation technique for civil structures in Huazhong University of Science and Technology (HUST) are introduced. The achievements include project applications, experimental research results and theoretical innovation.  相似文献   
47.
目的对区域每一点的适居性进行综合评价。方法采用AHP法对因子赋权。结果首先构建了区域适居性评价因子体系,接着利用图文数据源,在地理信息系统空间分析模块的支持下,通过单因子空间分析、布尔逻辑运算和复合叠置分析对区域适居性进行综合评价。结论运用GIS空间分析技术能实现多数据源处理、多指标叠合分析、多维度显示,这些功能为适居性评价提供了科学、客观、高效、直观的方法支持,今后应进一步提高评价的可靠性。  相似文献   
48.
With the capacity of energy conversion from heat to electricity directly, thermoelectric materials have been considered as an alternative solution to global energy crisis. In this work, Cu modified Bi_(0.5)Sb_(1.5)Te_3(BST)composites are prepared by a facile electroless plating Cu method, spark plasma sintering, and annealing. The annealed 0.22 wt.%Cu/BST has an enhanced peak Figure of Merit(z T) of ~ 0.71 at 573 K with high average z T of0.65 in the wide temperature range between 300 and 573 K. Due to the significant increase of electrical conductivity and low lattice thermal conductivity, the annealed 0.22 wt.%Cu/BST shifts peak z T to high temperature, and shows 492% enhancement than that of pristine BST with z T of 0.12 at 573 K. Through detailed structural characterization of the annealed 0.22 wt.%Cu/BST, we found that Cu can dope into BST matrix and further form Cu2 Te nanoprecipitates, dislocations, and massive grain boundaries, leading to a low lattice thermal conductivity of 0.30 Wm-1 K-1 in the annealed 0.22 wt.%Cu/BST. Such enhanced peak z T in high-temperature and high average z T in the wide temperature range shows that the electroless plating Cu method and annealing can improve the thermoelectric performance of commercial BST and expand the applicability of Bi_2Te_3 thermoelectric materials in the power generations.  相似文献   
49.
The technology of Ultra-High Voltage (UHV) transmission requires higher dependability for electric power grid. Power Grid Communication Networking (PGCN), the fundamental information infrastructure, severs data transmission including control signal, protection signal, and common data services. Dependability is the necessary requirement to ensure services timely and accurately. Dependability analysis aims to predicate operation status and provide suitable strategies getting rid of the potential dangers. Due to the dependability of PGCN may be affected by external environment, devices quality, implementation strategies, and so on, the scale explosion and the structure complexity make the PGCN's dependability much challenging. In this paper, with the observation of interdependency between power grid and PGCN, we propose an electricity services based dependability analysis model of PGCN. The model includes methods of analyzing its dependability and procedures of designing the dependable strategies. We respectively discuss the deterministic analysis method based on matrix analysis and stochastic analysis model based on stochastic Petri nets.  相似文献   
50.
江Kun  董荣 《安徽科技》1998,(10):4-6
近几年来,在高寒山区发展蔬菜产业,取得了明显的成效,已经成为我省山区实现扶贫攻坚目标的一条有效措施,受到当地农民的普遍欢迎。 一、发展高山反季节蔬莱是山区农民脱贫致富的一条有效途径  相似文献   
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