用弥散单元法计算平面及轴对称热应力

用弥散单元法计算平面及轴对称热应力@曾宪伟...

重视边远分散单位党的建设

改革开放、发展社会主义市场经济,给部队建设特别是边远分散单位党的建设带来许多新情况、新问题.一是小远散单位条件艰苦,军地反差在这些单位表现得更加突出.二是一些小远散单位的主官忽视党支部集体领导,个人拍板说了算的现象随之增多,基层党组织贯彻民主集中制的质量有下降趋势.三是一些小远散单位的干部骨干对军队的特殊性认识不清,受地方影响,组织纪律观念淡薄,工作随意性大等等.针对这些新情况新问题,我们认为,在抓小远散单位的建设上必须注意以下两点.一、越是边远分散单位越要切实把党的建设摆上位置一要克服重大轻小的思想,牢固树立全面建设的整体意识.要切实把边远分散单位当成党委的“心头肉”,不因其小而丢弃,不因其远而减力,不因其散而疏漏,使基层党的建设得到均衡发展.二要克服重表轻本的思想,牢固树立抓好党支部建设的责任意识.长期以来,在对小远散单位建设的认识上存在着一种偏差,就是只重其表,忽略其本.

单分组散列函数的口令安全存储算法的设计与实现

随着互联网的普及和计算机技术的发展,信息安全愈加重要。保护个人隐私的数据安全已经成为每个人关注的焦点。其中,身份认证技术是必不可少的,目前常用的用户认证方式主要是口令认证。通常使用散列函数处理静态口令,依据散列函数原理填充位数过多影响口令的安全。因此,文章依照散列函数的设计原则,首先从外部和内部的结构上重新设计一个输入长度小于256比特的安全单分组散列函数(SSBH)。其次提出了基于SSBH的口令安全存储算法。通过实验表明SSBH函数具有更高的可靠性和运行效率。

单城市聚散均衡机制与多城市非均衡发展

城市化进程的内部运行机制是通过微观主体追求比较利益、互补利益和选择利益,重新配置资源和经济要素,使经济不断地处于聚集和扩散的动态均衡状态。不仅聚集要素内部之间和扩散要素内部之间要保持局部均衡,同时,聚集要素与扩散要素之间要保持一般均衡。聚散均衡是非均衡发展的前提、基础,非均衡发展是聚散均衡的目的和归宿。政府应利用聚散均衡规律,推进城市非均衡发展。

基于单分组散列函数的安卓应用程序保护方案的设计

针对安卓手机的安全保护机制,提出了一种基于单分组散列函数的数字签名机制和关键资源保护机制相结合的保护方案.首先该方案通过安全文件生成器将关键资源文件的哈希值保存到安全文件中,然后使用数字签名机制保证安全文件不被篡改,最后由关键资源保护机制确保关键资源文件的完整性,其中包括对被篡改的关键资源进行纠错.实验结果表明,本方案不仅能够有效地防止安卓应用程序被篡改,而且增加了逆向攻击的难度.

31例外伤性硬膜外血肿致单瞳散大影响其预后的临床因素分析

2002年1月～2006年5月我院收治颅脑损伤硬膜外血肿手术患者100例，其中硬膜外血肿合并单瞳孔散大31例，占同型颅内血肿的31％左右。现将影响其预后因素临床分析如下。

加强对门诊医疗单位麻醉药品的管理

我区属内陆省军区,建制部队少,机关、直属小散单位多。长期以来,由于对麻醉药品缺乏有效的管理,致使麻醉药品在购、储、用等环节上存在一些问题。(如:麻醉药品贮量过大、陈旧产品多、管理制度不健全、“五专”不落实、使用把关不严等)。近年来,我们结合基层医疗单位的特点,在摸清各单位麻醉药品底数的基础上,严把购入、储存、使用三关,收到良好效果,现报告如下:

Unraveling the roles of atomically-dispersed Au in boosting photocatalytic CO_(2)reduction and aryl alcohol oxidation

Atomically-dispersed metal-based materials represent an emerging class of photocatalysts attributed to their high catalytic activity,abundant surface active sites,and efficient charge separation.Nevertheless,the roles of different forms of atomically-dispersed metals(i.e.,single-atoms and atomic clusters)in photocatalytic reactions remain ambiguous.Herein,we developed an ethylenediamine(EDA)-assisted reduction method to controllably synthesize atomically dispersed Au in the forms of Au single atoms(Au_(SA)),Au clusters(Au_(C)),and a mixed-phase of Au_(SA)and Au_(C)(Au_(SA+C))on CdS.In addition,we elucidate the synergistic effect of Au_(SA)and Au_(C)in enhancing the photocatalytic performance of CdS substrates for simultaneous CO_(2)reduction and aryl alcohol oxidation.Specifically,Au_(SA)can effectively lower the energy barrier for the CO_(2)→*COOH conversion,while Au_(C)can enhance the adsorption of alcohols and reduce the energy barrier for dehydrogenation.As a result,the Au_(SA)and Au_(C)co-loaded CdS show impressive overall photocatalytic CO_(2)conversion performance,achieving remarkable CO and BAD production rates of 4.43 and 4.71 mmol g^(−1)h^(−1),with the selectivities of 93%and 99%,respectively.More importantly,the solar-to-chemical conversion efficiency of Au_(SA+C)/CdS reaches 0.57%,which is over fivefold higher than the typical solar-to-biomass conversion efficiency found in nature(ca.0.1%).This study comprehensively describes the roles of different forms of atomically-dispersed metals and their synergistic effects in photocatalytic reactions,which is anticipated to pave a new avenue in energy and environmental applications.

大魔群的历史与发展

有限单群分类定理的证明是本世纪初取得的一项重大成就。作为有限单群中最大的散单群,大魔群自20世纪70年代就以其复杂的结构和迷人的性质受到广泛关注。文章介绍了人们对大魔群求索与认知的过程,分析了它与数学其他学科乃至物理学的关系。

Research on the correlation between the dual diffusion behavior of zinc in InGaAs/InP single-photon avalanche photodiodes and device performance

The development of InGaAs/InP single-photon avalanche photodiodes(SPADs)necessitates the utiliza-tion of a two-element diffusion technique to achieve accurate manipulation of the multiplication width and the dis-tribution of its electric field.Regarding the issue of accurately predicting the depth of diffusion in InGaAs/InP SPAD,simulation analysis and device development were carried out,focusing on the dual diffusion behavior of zinc atoms.A formula of X_(j)=k√t-t_(0)+c to quantitatively predict the diffusion depth is obtained by fitting the simulated twice-diffusion depths based on a two-dimensional(2D)model.The 2D impurity morphologies and the one-dimensional impurity profiles for the dual-diffused region are characterized by using scanning electron micros-copy and secondary ion mass spectrometry as a function of the diffusion depth,respectively.InGaAs/InP SPAD devices with different dual-diffusion conditions are also fabricated,which show breakdown behaviors well consis-tent with the simulated results under the same junction geometries.The dark count rate(DCR)of the device de-creased as the multiplication width increased,as indicated by the results.DCRs of 2×10^(6),1×10^(5),4×10^(4),and 2×10^(4) were achieved at temperatures of 300 K,273 K,263 K,and 253 K,respectively,with a bias voltage of 3 V,when the multiplication width was 1.5µm.These results demonstrate an effective prediction route for accu-rately controlling the dual-diffused zinc junction geometry in InP-based planar device processing.

Radial mixing and segregation of granular bed bi-dispersed both in particle size and density within horizontal rotating drum

Taking simultaneous variations in both particle volume and density into account, the radial mixing and segregation of binary granular bed in a rotating drum half loaded were investigated by a 3D discrete element method. Then, based on the competition theory of condensation and percolation, radial segregation due to differences in particle volume and/or density was analyzed. The results show that if either percolation effect induced by volume difference or condensation effect induced by density difference dominates in the active layer of moving bed, separation will occur. Controlling the volume ratio or density ratio of the two types of particles can achieve an equilibrium state between percolation and condensation, and then homogenous mixture can be obtained. When the percolation balances with the condensation, the relationship between volume ratioand density ratiopresents nearly a power function. Scaling up a rotating drum will not affect the mixing degree of the granular bed so long as the volume ratio and density ratio are predefined.

Dispersion of copper oxide supported on γ-alumina and its sulfation properties

CuO/γ-Al2O3 catalysts were prepared by impregnation with different CuO loadings. The dispersion of CuO supported on γ-Al2O3 support was studied using X-ray diffraction （XRD）, scanning electron microscopy （SEM）, and temperature programmed reduction （TPR）. The dispersion threshold of CuO in γ-Al2O3 determined by X-ray quantitative analysis was 0.275 g/g, i.e., 0.275CuAl. Highly dispersed CuO or crystalline CuO would appear on the γ-Al2O3 support when CuO loading was below or more than its dispersion threshold. TPR experiments show that reduction peak temperature ranges of 0.1CuAl and pure CuO are 420-690 °C and 290-380 °C, respectively. 0.1CuAl is not easily reduced due to interaction between CuO and γ-Al2O3. 0.5CuAl shows a two-step reduction range during 210-300 °C and 410-730 °C, which confirms the existence of highly dispersed CuO and crystalline CuO. The sulfation experiments show the optimal CuO loading amount is far below its dispersion threshold, and copper oxide supported on γ-Al2O3 is in the form of submonolayer.

Surfactant-assisted hydrothermally synthesized MoS_2 samples with controllable morphologies and structures for anthracene hydrogenation

MoS_2 samples with controllable morphologies and structures were synthesized using surfactantassisted hydrothermal processes.The effects of surfactants（PEG,PVP,P123,SDS,AOT,and CTAB）on the morphologies and structures of MoS_2 samples were investigated.The results revealed that spherical,bulk-like,and flower-like MoS_2 particles assembled by NH4~＋-intercalated MoS_2 nano-sheets were synthesized.The morphologies of the MoS_2 samples and their structures（including the slab length and the number of stacked layers） of MoS_2 nano-sheets in these samples could be controlled by adjusting the surfactants.Mono-dispersed spherical MoS_2 particles could be synthesized with PEG via the creation of MoS_2 nano-sheets with slab lengths shorter than 15 nm and fewer than six stacked layers.Possible formation mechanisms of these MoS_2 samples created via surfactant-assisted hydrothermal processes are proposed.Further,the catalytic activities of MoS_2 samples for anthracene hydrogenation were evaluated in a slurry-bed reactor.The catalyst synthesized with the surfactant PEG exhibited the highest catalytic hydrogenation activity.Compared with the other catalysts,it had a smaller particle size,mono-dispersed spherical morphology,shorter slab length,and fewer stacked layers;these were all beneficial to exposing its active edges.This work provides an efficient approach to synthesize transition metal sulfides with controllable morphologies and structures.

流化床内沉浸管磨损特性的理论预测

基于气固两相双流体模型和颗粒动力学方法模拟流化床内气体和颗粒流动特性,采用单层能量耗散磨损模型模拟沉浸管的磨损率和亚网格尺度模型(SGS)模拟气相湍流流动,同时应用贴体坐标系使计算网格与沉浸管表面相吻合。模拟计算得到了沉浸管的瞬时磨损率和时均磨损率。数值模拟流化床内气固两相流体动力行为和沉浸管磨损特性。模拟计算结果表明沉浸管磨损受气泡尾涡及颗粒运动的直接影响。分析了沿沉浸管环向时均磨损率的变化规律。当沉浸管横向相对节距为2．0～3．0时磨损率达最大。数值模拟得到的流化床内构件磨损率与前人的实验结果和数值模拟相吻合。

Applicability of Markov chain-based stochastic model for bubbling fluidized beds

A Markov chain-based stochastic model （MCM） is developed to simulate the movement of particles in a 2D bubbling fluidized bed （BFB）. The state spaces are determined by the discretized physical cells of the bed, and the transition probability matrix is directly calculated by the results of a discrete element method （DEM） simulation. The Markov property of the BFB is discussed by the comparison results calculated from both static and dynamic transition probability matrices. The static matrix is calculated based on the Markov chain while the dynamic matrix is calculated based on the memory property of the particle movement. Results show that the difference in the trends of particle movement between the static and dynamic matrix calculation is very small. Besides, the particle mixing curves of the MCM and DEM have the same trend and similar numerical values, and the details show the time averaged characteristic of the MCM and also expose its shortcoming in describing the instantaneous particle dynamics in the BFB.

A Single Mode980 nm In Ga As/Ga As/Al Ga As Large Optical Cavity Quantum Well Laser with Low Vertical Divergence Angle

To achieve high optical power as well as low vertical divergence angle,a new kind of optim ized large opti- cal cavity (L OC) structure is applied to a ridge waveguide 980 nm In Ga As/ Ga As/ Al Ga As m ulti- quantum well laser.The optical power density in the waveguide is successfully reduced.The maxim um output power is more than 40 0 m W with a slope efficiency of 0 .89W/ A and the far- field vertical divergence angle is lowered to 2 3°.

对抗洪抢险部队住院病员发病情况分析与思考

1998年8月20日、22日,我们在随首长看望、慰问伤病员的同时,对正在庐山疗养院住院治疗的72名伤病员的发病情况进行了调查统计。现将情况分析报告如下: 1 基本情况 72名病员中,军官7人、士兵65人,分别占9.7％、90.3％。其中,因伤17人,占23.68％;因病55人,占76.48％。除1例疟疾外无其它传染病员。

精做“小文章”

精做“小文章”杨耀奎张军伟我部驻守在东海某群岛的４个岛屿５５个点上，小散单位占执勤单位的三分之二，最小的单位只有４名战士，有的一个营就有八九个执勤点。近几年来，小散单位文化生活面貌虽有明显的改观，但由于受客观条件限制，总有这样那样的问题。一是任务重，...

Mechanical stirring for highly efficient gas injection refining

In gas injection refining processes,wide dispersion of small bubbles in the bath is indispensable for high refining efficiency.Eccentric mechanical stirring with unidirectional impeller rotation was tested using a water model for pursuing better bubble disintegration and dispersion.Effects of various factors on bubble disintegration and dispersion were investigated.These factors were stirring mode,eccentricity and rotation speed,nozzle structure,nozzle immersion depth,and gas flow rate.Gas injection from a nozzle at the end of the impeller shaft and from an immersed lance was studied.Under eccentric stirring,a vortex was formed away from the shaft.Small bubbles were produced in the strong turbulence or high shear stress field near the rotating impeller and moved in the direction to the vortex keeping up with the macroscopic flow induced by the mechanical stirring.Thus small bubbles could disperse widely in the bath under eccentric stirring with unidirectional rotation.