易面各向异性羰基铁@SiO_(2)/聚氨酯复合材料吸波性能及其吸收机制

为了在低频段实现薄层高效微波吸收,首先通过机械球磨技术制备了具有易面各向异性的羰基铁粉;其次通过表面改性在羰基铁粉表面沉积了一层纳米SiO_(2);并通扫描电子显微镜、透射电子显微镜、振动样品磁强计、X射线衍射仪以及矢量网络分析仪对其进行测试表征。实验结果表明,易面各向异性羰基铁@SiO_(2)/聚氨酯复合材料不仅在垂直入射条件下具有优异的吸波性能,同时在斜入射条件下也具有优异的吸波性能;在垂直入射条件下,其反射损耗峰在S波段达到了−43 dB,意味着99.99%的电磁波被高效吸收;在入射角度为60°、厚度为1.5 mm时,在5~15 GHz范围内均能获得有效吸波,真正实现了薄层、宽带、宽角度高效吸收,对于解决先进武器装备急需的高效雷达吸波涂层展现了强大的应用潜力。

取向易面型羰基铁复合物在超高频RFID天线中的应用研究

基于如何实现超高频RFID天线的小型化及拓宽带宽这一课题进行研究,以球状羰基铁为原料,采用湿法球磨工艺对其进行扁平化处理,使其具有易磁化面,通过磁场取向工艺对磁粉/橡胶复合物进行取向,使复合物中磁粉的易磁化面平行排列。电磁参数测量结果显示,复合物在880 MHz磁导率实部达到7.77,磁损耗因子为0.18,介电常数实部为11.08,介电损耗因子仅为0.01。通过CST工作室套装(CST)软件模拟该复合物作为天线的发射特性,模拟结果发现,其对应的中心发射频率在880 MHz,回波损耗达到-14.5 dB,小于-10 dB的有效发射带宽为94 MHz,同时天线尺寸较非磁性天线有大幅度缩减。

应用铁磁共振法测量易(111)面YIG磁膜的K_1,K_u和γ

本文全面地分析了用铁磁共振法测量易(111)YIG(钇铁石榴石)磁性薄膜的立方磁晶各向异性常数K_1、单轴各向异性常数K_u以及旋磁比γ的理论公式,从而找到了将静磁场H加在YIG薄膜的((?)10)面上的测量及计算程序的简便方案.文中指出,在[11(?)]轴上,外加静磁场H和磁化强度M方向是不一致的,文中还给出了易(111)面YIG磁性薄膜K_1,H_u和γ的测量结果.

不同易密实超薄罩面处治方案应用效果分析

为了验证易密实超薄罩面作为一种预防性养护技术对改善路表功能、减少车辙、提高耐磨、抗滑的效果,该文结合江西省某高速公路沥青路面技术状况的平整度、车辙、抗滑等性能指标,采用了铣刨回补后易密实超薄罩面、精铣刨后易密实超薄罩面以及直接易密实超薄罩面3种处治方案,对不同处治方案路段的应用效果进行跟踪观测,结果表明:3种处治方案对路面平整度改善效果均不明显,但对路面车辙和抗滑性能处治效果较好,其中车辙改善效果铣刨回补方案最好,其次为精铣刨后罩面,最后为直接易密实超薄罩面。

易冒顶综采工作面支架回撤方法

开滦集团钱家营矿1376W综采工作面采用ZY9200-20/42D型液压支架,其支架体积、收尾空间、空顶面积及顶板压力均较大,回撤困难。为了安全、高效、经济回撤支架,根据该工作面的实际情况,采用双掩护支架加强工作面顶板支护,确保了工作面支架回撤作业安全。

高速公路易密实薄层罩面实施效果评价及应用经验总结

本文通过检测数据分析和现场调查,对江西省高速公路易密实薄层罩面的实施效果进行了跟踪检测和评价,并在江西省易密实薄层罩面应用经验的基础上,对其适用性、便利性、经济性和环保性进行了分析,最后归纳总结了易密实薄层罩面在设计阶段和施工阶段的注意事项,为易密实薄层罩面技术在江西省高速公路的进一步推广应用提供借鉴和参考。

WiNDOWS 3.0电子衍射谱理论分析系统

本文论述了Windows 3.0电子衍射谱理论分析系统的基本原理,并详细地介绍了它们的功能和特点。

Water, CO_2 and Energy Exchange at Vegetation-air Interface

[Objective] The aim was to analyze water and heat fluxes, CO2 fluxes and energy balance in wheat ecosystem in Luancheng County of Hebei Province. [Method] Based on data of water and heat flux, and CO2 fluxes, routine meteorological and biomass data in Luancheng in 2008, water and heat fluxes, CO2 fluxes and energy balance in wheat ecosystem were explored. [Result] The results showed that latent and sensible heat and CO2 fluxes were of obvious daily and seasonal changes; latent and sensible heat fluxes shaped an inverted U in daily change, and CO2 fluxes were of a U-shape; daily flux peak differed significantly. Furthermore, the change of latent heat, sensible heat and CO2 fluxes were closely related to environ- mental factors. Detailedly, the three were sensitive to light intensity and net radiation, and correlation coefficients were 0.92, 0.66, 0.65 and 0.90, 0.69, 0.74, respectively. Besides, the fluxes, sensitive to temperature, proved better in sunny day, especially for latent flux which is more sensitive to water in soils after precipitation. In addition, closure degree of energy balance in wheat fields was 0.91 and non-closure, caused by measurement error and neglection of heat storage, was observed, too. What＇s more. closure degree differed in months and time periods within a day. [Conclusion] The research concluded water and heat fluxes, CO2 fluxes, transport mechanisms and concerning factors, providing scientific reference for revealing mechanism of evapo- ration and heat dissipation of canopy, relationship between photosynthesis and water use efficiencyand energy distribution mechanism.

黔东南余凯路志留系翁项群地层滑坡分析

黔东南余凯路建设过程发生的滑坡多发育于志留系中上统翁项群地层,该套地层具有特殊的岩性特征和易滑结构面是其易产生滑坡的内在因素。从易滑结构面着手将翁项群地层滑坡归为顺层滑坡、切层滑坡和堆积体滑坡三种类型,分析了滑坡所在区域的环境地质特点和滑坡成因。结合翁项群地层滑坡勘察和处治经验,提出了勘察和处治设计应注意的问题。

Soybean Production & Trade in China——Implicated Impacts of GMO Regulation on Soybean Market

This paper provides an overview of the economic analysis,policy debate,and methodological issues on soybean production, import and export, and impacts of GMO regulation on soybean foreign trade of China. The paper analyzes China’s soybean production capability and discovers that the present yield of China’s soybean plant system cannot satisfy the domestic demand.The paperalso provides the method to solve such matters by using the result of a modified Cobb-Douglas model. In the third section of this paper, the impacts of GMO regulation on soybean trade and marketin China are analyzed.In this section,we provide a methodological issue to analyze the impacts of such regulation on trade.The paper then explains the implicated result induced by such regulations.

The Some New Aspects of the International Business Theory and International Economy

Different positions of the member states of the World Trade Organization （WTO）, especially the developed and developing countries and also the United States of America （USA）, the European Union （EU）, and Japan representatives, were observed during the Doha Round of trade negotiations under the WTO. The problems of agriculture protection in the developed countries, for example in the EU and USA and also in the developing countries, were becoming serious obstacles during the negotiations. Despite the undeniable benefits of the multilateral WTO forum for trade liberalization, the rapid increase of North-South bilateral and multilateral free trade areas （FTAs） begs a systematic explanation for why some forums are prioritized relative to others. The main aim of the article is the presentation of some new aspects of the international business theory in the context of international economy. The article presents the mercantilist tendencies in the international trade policy, the theory of public choice in the foreign trade policy, protectionist pressures in different political systems, the level of protectionist pressures, food producers＇ pressure, and conflicts between the tendencies to sustainable international trade liberalization and environmental protection.

Carbon Emissions in International Trade： Calculating Size and Causes

Due to ongoing growth in carbon emission, many governments＇ have taken measures to curb it. Thus, it is of great importance to measure carbon emissions in international trade and probe into the causes behind them. This paper first applies inputoutput model then it estimates the carbon emissions embodied in China＇s international trade in 2002, 2005 and 2007. Using structural decomposition analysis, this paper measures carbon emissions in international trade by their scale effect, composition effect and intensity effect. Our results illustrate： （1） a rapidly-rising net export of carbon emissions for China, and （2） scale effect and composition effect stimulates carbon emissions embodied in exports, while intensity effect discourages it.

Numerical simulation for explosion wave propagation of combustible mixture gas

A two-dimensional multi-material code was indigenously developed to investigate the effects of duct boundary conditions and ignition positions on the propagation law of explosion wave for hydrogen and methane-based combustible mixture gas. In the code,Young's technique was employed to track the interface between the explosion products and air,and combustible function model was adopted to simulate ignition process. The code was employed to study explosion flow field inside and outside the duct and to obtain peak pressures in different boundary conditions and ignition positions. Numerical results suggest that during the propagation in a duct,for point initiation,the curvature of spherical wave front gradually decreases and evolves into plane wave. Due to the multiple reflections on the duct wall,multi-peak values appear on pressure-time curve,and peak pressure strongly relies on the duct boundary conditions and ignition position. When explosive wave reaches the exit of the duct,explosion products expand outward and forms shock wave in air. Multiple rarefaction waves also occur and propagate upstream along the duct to decrease the pressure in the duct. The results are in agreement with one-dimensional isentropic gas flow theory of the explosion products,and indicate that the ignition model and multi-material interface treatment method are feasible.

Facile Synthesis of Micro/Nano Binary Dendritic Gold Structures for SERS and Superhydrophobic Applications

Via a galvanic displacement reaction, well-defined micro/nano binary dendritic gold structures were prepared on silicon wafers in fluoride acid solution containing HAuCI4 at 50 ℃. The gold deposits were characterized with scanning electron microscopy （SEM）, energy-dispersive X-ray （EDX） spectrum and X-ray diffraction （XRD）. The investigation of the surface-enhanced Raman scattering （SERS） reveals that the film of gold dendrites was an excellent substrate with significant enhancement effect. Also, the gold dendritic structured surface exhibited a remarkable superhydrophobic property with a contact angle of approximately 165° and low contact angle hysteresis after further simple surface modification with n-dodecanethiol.

The Developmental Stages of Rice （Bap） Culture in Korea： From Food Insufficiency towards Trade Dependency

The aim of this paper is to examine the developmental stages of rice culture in Korea. It is divided into five sections： （1） first stage （Japanese colonial period-1959）： absolute food insufficiency, （2） second stage （1960s）： encouraging the use of flour ＆ rice with mixed grains for food, （3） third stage （1970s）： rice self-sufficiency, （4） fourth stage （1980s）： change of rice culture, （5） fitch stage （since1990s）： stabilization/stagnation of rice culture in the era of globalization.

Grinding Characteristics Of Directionally Aligned SiC Whisker Wheel - Comparison With A12O3 Fiber Wheel

A unique SiC whisker wheel was invented,in which the whiskers were aligned normally to the grinding wheel surface.In this paper,grindabilities of the SiC whisker wheel are investigated and compared with those of other wheels of SiC grains,Al2O3 grains,as well as Al2O3 long and short fibres which were also aligned normally to the grinding wheel surface,respectively.The main research contents concern grinding characteristics of a directionally aligned SiC whisker wheel such as material-removal volume,wheel-wear rates,integrity of the ground surfaces,grinding ratios and grinding efficiency.Furthermore,grinding wheels of whiskers and fibres have a common disadvantage:they tend to load easily.The authors have proposed a simple method of loading-free grinding to overcome this propensity and investigate some related grinding characteristics under loading-free grinding conditions.

Analysis on Rice Production and International Trade in Vietnam

This paper introduces Vietnam's climate condition,main rice production regions and analyses the expansion of rice planting area,rice cropping system during the last decades.The result from the change of rice production,planting area,yield,and rice trade indicates that the economic reforms in Vietnam from 1986 have contributed to a spectacular rise in rice production and exports.However,there are still problems and opportunities for rice production and export in Vietnam.The paper suggests that Vietnam should make the most use of the advanced international rice cultivars and technology to improve irrigation and water conservancy facilities to benefit rice farmer and consolidate Vietnam to be the major exporter of rice in the world market.

Fine-control-valve of halide perovskite single crystal quality for high performance X-ray detection

Halide perovskite single crystals(HPSCs)provide a unique platform to study the optoelectronic properties of such emerging semiconductor materials,while the temperature induced crystal growth method often has an increased solute integration speed and/or unavoidable solute consumption,resulting in a soaring or slumping crystal growth rate of HPSCs.Here,we developed a universal and facile solvent-vola tilization-limited-growth(SVG)strategy to finely control the crystal growth rate by the fine-control-valve for high quality crystal grown through solution processes.The grown HPSCs by SVG method exhibited a record low trap density of 2.8×10^(8)cm^(-3)and a high charge carrier mobility-lifetime product(μτproduct)of 0.021 cm2/V,indicating the excellent crystal quality.The crystal surface defects were further passivated by oxygen suppliers as Lewis base,which led to a reduction of surface leakage current by two times when using for low dose rate X-ray detection.Such HPSC X-ray detector displayed a high sensitivity of 1274μC/(Gyair cm^(2))with a lowest detectable dose rate of 0.56μGyair/s under 120 keV hard X-ray.Further applications including alloy composition analysis and metal flaw detection by HPSC detectors were also demonstrated,which not only shows the bright future for product quality inspection and non-destructive materials analysis,but also paves the way for growing high quality single crystals and fabricating polycrystalline films.

Nanomagnetic CoPt truncated octahedrons:facile synthesis,superior electrocatalytic activity and stability for methanol oxidation

Nanomagnetic CoPt truncated octahedral nanoparticles （TONPs） were successfully synthesised through a facile one-pot strategy. These single crystal CoPt TONPs with an average size of about 8 nm exhibit excellent electrocatalytic performance of both activity and stability for methanol oxidation reaction （MOR）. The mass and specific activities of CoPt TONPs is 8 and 6 times higher than that of standard commercial Pt/C, respectively. After accelerated durability test （ADT）, the loss of electrochemical surface area （ECSA） for CoPt TONPs is only 18.5%, which is significantly less than that of commercial Pt/C （68.2%）, indicating that CoPt TONPs possess much better stability than commercial Pt/C in the prolonged operation. The Curie temperature of CoPt TONPs down to 8 nm is as high as 350 K with weak ferromagntism at room temperature （RT）, which is greatly valuable for recycling in the eletrocatalytic applications.

Poisson-Fokker-Planck model for biomolecules translocation through nanopore driven by electroosmotic flow

A non-continuous electroosmotic flow model(PFP model)is built based on Poisson equation,Fokker-Planck equation and Navier-Stokse equation,and used to predict the DNA molecule translocation through nanopore.PFP model discards the continuum assumption of ion translocation and considers ions as discrete particles.In addition,this model includes the contributions of Coulomb electrostatic potential between ions,Brownian motion of ions and viscous friction to ion transportation.No ionic diffusion coefficient and other phenomenological parameters are needed in the PFP model.It is worth noting that the PFP model can describe non-equilibrium electroosmotic transportation of ions in a channel of a size comparable with the mean free path of ion.A modified clustering method is proposed for the numerical solution of PFP model,and ion current translocation through nanopore with a radius of 1 nm is simulated using the modified clustering method.The external electric field,wall charge density of nanopore,surface charge density of DNA,as well as ion average number density,influence the electroosmotic velocity profile of electrolyte solution,the velocity of DNA translocation through nanopore and ion current blockade.Results show that the ion average number density of electrolyte and surface charge density of nanopore have a significant effect on the translocation velocity of DNA and the ion current blockade.The translocation velocity of DNA is proportional to the surface charge density of nanopore,and is inversely proportional to ion average number density of electrolyte solution.Thus,the translocation velocity of DNAs can be controlled to improve the accuracy of sequencing by adjusting the external electric field,ion average number density of electrolyte and surface charge density of nanopore.Ion current decreases when the ion average number density is larger than the critical value and increases when the ion average number density is lower than the critical value.Our numerical simulation shows that the translocation velocity of DNA given by the PFP model agrees with the experimental,results better than that given by PNP model or PB model.