物流成本的推断方法研究

原本方物流成本和第三方物流成本会因各自条件明显欠缺而难以集中并进行会计核算．尽管如此,却可以运用统计方法对它们进行估算,即在理清物流成本结构的基础上,分别对物流需求者和物流经营者总体的有关特征进行抽样推断,进而估算出原本方物流成本和第三方物流成本以及由它们合成的物流供给成本．抽样推断方法具有科学性和可操作性,能有效解决物流成本估算问题,其应用成果为制定物流发展规划或设计物流建设方案提供了依据,为解决物流卫星账户构建之瓶颈问题奠定了重要基础．     

Phase Transitions of an Epidemic Spreading Model in Small-World Networks

We propose a modified susceptible-infected-refractory-susceptible (SIRS) model to investigate the global oscillations of the epidemic spreading inWatts-Strogatz (WS) small-world networks. It is found that when an individual immunity does not change or decays slowly in an immune period, the system can exhibit complex transition from an infecting stationary state to a large amplitude sustained oscillation or an absorbing state with no infection. When the immunity decays rapidly in the immune period, the transition to the global oscillation disappears and there is no oscillation. Furthermore, based on thespatio-temporal evolution patterns and the phase diagram, it is disclosed that a long immunity period takes an important role in the emergence of the global oscillation in small-world networks.     

酪氨酸希夫碱邻菲咯啉氧钒配合物的合成、结构及其与DNA相互作用研究

合成了一个新的L-酪氨酸萘酚醛希夫碱及邻菲咯啉混配氧钒配合物[VO(Naph-L-Tyr)(Phen)]•CH₃OH (Naph-L-Tyr＝2-羟基-1-萘甲醛与L-酪氨酸形成的希夫碱, Phen＝1,10-邻菲咯啉). 利用元素分析、红外光谱和X射线单晶衍射进行了表征. 晶体结构测定表明, 该晶体属于三斜晶系, P-1空间群, 其晶体学数据: a＝1.00023(11) nm, b＝1.13478(12) nm, c＝1.34076(15) nm, a＝108.118(2)o, b＝96.3920(10)o, g＝92.4010(10)o, V＝1.4326(3) nm³, Z＝2, D_c＝1.420 g/cm³, F(000)＝634, 最终的偏差因子为R₁＝0.0670, wR₂＝0.1324 [I＞2s (I)]. 以钒原子为中心形成了六配位变形的八面体构型, 晶体中相邻分子之间通过氢键和π-π相互作用形成一维链状结构. 利用紫外吸收光谱、荧光光谱、圆二色光谱和粘度测量等研究了配合物与小牛胸腺DNA (CT-DNA)的作用, 结果表明配合物以插入方式与CT-DNA作用. 琼脂糖凝胶电泳法研究表明, 配合物对质粒pBR322 DNA分子具有切割作用.     

含不同质子供体的2-苯基苯并三唑衍生物激发态质子转移的理论研究

用密度泛函理论(DFT)和二级微扰理论(MP2)研究了带不同质子供体的2-苯基苯并三唑衍生物: 2-(2-羟苯基)苯并三唑(H-TIN), 2-(2-氨苯基)苯并三唑(APyBT)和2-(2-巯苯基)苯并三唑(MPyBT)的激发态分子内质子转移(ESIPT)性质以及它们作为紫外光吸收剂的光物理机制. 结果表明, 在基态时三个化合物的最稳定异构体是均存在分子内氢键的正常构型N, 而互变异构体T和其扭曲构型T_twisted都是不稳定的. 激发态势能曲线表明H-TIN和APyBT的ESIPT分别需要克服约7.06和20.7 kJ/mol的能垒, 而MPyBT的ESIPT无需能垒|同时结合分子轨道, 电荷差分密度三维立体图的分析结果表明三个化合物都能发生ESIPT, 并且伴随有扭曲分子内电荷转移, 这些原因均表明它们都具有好的紫外光稳定作用.     

超支化聚苯乙烯-线型聚苯乙烯-超支化聚甲基丙烯酸甲酯三嵌段聚合物的合成与表征

合成了超支化聚苯乙烯-线型聚苯乙烯-超支化聚甲基丙烯酸甲酯三嵌段聚合物(HPS-b-LPS-b-HPMMA). 首先分别合成了带有炔基和溴的三硫代碳酸酯(ATC和BTC), 然后通过苯乙烯(St)的可逆加成-断裂链转移(RAFT)聚合, 制得端炔基和端基溴的线型聚苯乙烯大分子RAFT试剂, 然后将大分子RAFT试剂的溴末端转化为叠氮末端. 接着在大分子RAFT试剂存在情况下, 通过自缩合原子转移自由基共聚合(SCATRCP)分别制得端炔基超支化聚苯乙烯-线型聚苯乙烯(HPS-b-LPS)和端叠氮基超支化聚甲基丙烯酸甲酯-线型聚苯乙烯(HPMMA-b-LPS)两嵌段聚合物. 最后将两种两嵌段聚合物通过点击(click)反应偶合, 得到不对称的超支化-线型-超支化三嵌段聚合物HPS-b-LPS-b-HPMMA. 核磁共振氢谱(¹H NMR)、凝胶渗透色谱(GPC)结果表明, 所得产物分子量可控, 得到了预期结构的聚合物.     

PVP-SDS软模板引导常温水相一锅法合成银纳米棒

以银氨络离子为前躯体, 葡萄糖为还原剂, 在聚乙烯吡咯烷酮(PVP)和十二烷基硫酸钠(SDS)组成的软模板中反应, 首先得到形貌均一、粒径为(50±5) nm的纳米银颗粒, 随后自发生长成银纳米棒. 测试结果表明纳米银颗粒的等离子共振吸收峰在441 nm处, XRD表明其为面心立方体, 在(111)晶面有最强吸收|高分辨透射电镜(HRTEM)观察到的晶格条纹和孪晶面证实其为多重孪晶(MTP), 选区电子衍射(SAED)进一步证实了其具有五重孪晶结构. 由于孪晶结构具有很高的生长活性, 故推断上述孪晶纳米银颗粒经PVP-SDS软模板诱导, 在常温、水相且无需多元醇辅助的条件下, 仅通过受约束Ostwald熟化生长, 便可一锅法合成出各向异性的银纳米棒. 用该法替代高温有机相并加入晶种的多元醇方法, 提高了湿化学方法的实用性并可以显著降低制备一维银纳米材料的成本.     

砂磨法制备聚苯胺及其电化学性能的研究

首次采用砂磨法制备了导电态聚苯胺(PANI), 通过循环伏安和电导率的测试分析, 探讨了转速(N)、反应时间(t)、盐酸(HCl)浓度、十二烷基苯磺酸钠(SDBS)浓度和过硫酸铵(APS)浓度对产物氧化还原性及导电性能的影响|并采用红外光谱(FT-IR)对产物结构进行了表征. 结果表明: 当N为400 r/min, t为2 h, HCl与苯胺(An)的摩尔比(n_HCl/n_An)为4∶1, SDBS与An的摩尔比(n_SDBS/n_An)为1∶1, APS与An的物质的量比(n_APS/n_An)为0.8∶1时, 产物的各项性能达到最佳值|且砂磨法与乳液法制备的PANI结构相符, 电化学性能接近, 但是砂磨法的生产成本和环保优势十分显著(砂磨法的反应时间仅为乳液法的1/3, 用水量仅为乳液法的1/2).     

3D numerical simulation on fluid-structure interaction of structure subjected to underwater explosion with cavitation

In the underwater-shock environment,cavitation occurs near the structural surface.The dynamic response of fluid-structure interactions is influenced seriously by the cavitation effects.It is also the difficulty in the field of underwater explosion.With the traditional boundary element method and the finite element method(FEM),it is difficult to solve the nonlinear problem with cavitation effects subjected to the underwater explosion.To solve this problem,under the consideration of the cavitation effects and fluid compressibility,with fluid viscidity being neglected,a 3D numerical model of transient nonlinear fluid-structure interaction subjected to the underwater explosion is built.The fluid spectral element method(SEM) and the FEM are adopted to solve this model.After comparison with the FEM,it is shown that the SEM is more precise than the FEM,and the SEM results are in good coincidence with benchmark results and experiment results.Based on this,combined with ABAQUS,the transient fluid-structure interaction mechanism of the 3D submerged spherical shell and ship stiffened plates subjected to the underwater explosion is discussed,and the cavitation region and its influence on the structural dynamic responses are presented.The paper aims at providing references for relevant research on transient fluid-structure interaction of ship structures subjected to the underwater explosion.     

AN ARITHMETIC METHOD OF SEGMENTING MOVING AEOLIAN SAND PARTICLES＇ IMAGES FROM BACKGROUND INFORMATION OF DIGITAL HIGH-SPEED PHOTOGRAPHY IMAGES

为了深入理解多因素驱动下风沙颗粒起动的动态演化规律,需要准确地获得沙质床面附近沙粒群起跳的方式、速度和运动轨迹.以连续强激光源为照明的数字高速摄影技术是研究这类问题的有效手段,但由于风沙运动的高速摄影图像具有运动沙粒和静止床面的对比度小、相邻两帧图像相似性小等特点,原始图像叠加算法难以有效实现目标与背景的分割.该文提出了基于相邻的风沙运动图像灰度差值变化原理的图像分割算法.实例显示,只要选择合适的相邻图像灰度差值阈值和自适应二值化处理方法就能实现图像中运动沙粒与床面分割.当起跳沙粒浓度较低情况下,基于MATLAB平台的最小距离匹配的粒子追踪算法（PTV算法）能较为准确地恢复床面附近沙粒的运动轨迹.     

High-efficiency improved symmetric successive over-relaxation preconditioned conjugate gradient method for solving large-scale finite element linear equations

Fast solving large-scale linear equations in the finite element analysis is a classical subject in computational mechanics. It is a key technique in computer aided engineering （CAE） and computer aided manufacturing （CAM）. This paper presents a high-efficiency improved symmetric successive over-relaxation （ISSOR） preconditioned conjugate gradient （PCG） method, which maintains lelism consistent with the original form. Ideally, the by 50% as compared with the original algorithm. the convergence and inherent paralcomputation can It is suitable for be reduced nearly high-performance computing with its inherent basic high-efficiency operations. By comparing with the numerical results, it is shown that the proposed method has the best performance.