电子商务配送速度与客户退单的关联建模仿真

在电子商务中,产品的配送速度与客户的退单率之间存在着较为复杂的关联性,这种关联性受到所在地域、购买时间、运输能力、订单处理能力、人为因素等多方因素的影响十分复杂.传统的建模方法只能利用多个简单的线性关系进行描述,加入了更多的复杂约束过程的描述,模型复杂,无法准确反映两者关系.为解决上述问题,提出基于PLS_SEM算法的电子商务中产品的配送速度与客户退单的关系建模方法.根据PLS_SEM算法的构建复杂模型特有的优势,建立电子商务客户退单评价模型,并利用退单校验因子定量分析了电子商务中不同的变量对于客户退单的影响,可以较好地解决模型中存在的过多约束问题,保证建模准确性.仿真结果表明,利用PLS_SEM算法能够实现对电子商务中产品配送速度与客户退单的关系进行准确分析,效果令人满意.     

远场激光能量密度分布的数值与图像估算

激光在大气传输过程中,由于同大气分子与气溶胶粒子之间的相互作用而产生了一系列的效应,即大气衰减和大气湍流效应,导致能量不断减弱,并影响激光的远场能量密度分布.根据设计的激光远场能量密度分布测试系统进行外场实际试验测试,只能获得指定位置上的远场能量密度分布数据和激光光斑图像,为了获得任意位置的激光传输特性,研究了大气衰减和大气湍流对激光传输的影响.根据上述系统测得的指定位置的光斑图像及能量分布数据,通过软件仿真分析,估算任意位置的激光光斑能量密度分布,通过伪彩色变换,将激光光斑的灰度图像转换为连续变化的伪彩色图像,可以直观地观察光斑的远场能量密度分布.     

Change in the molecular weight distribution of poly(ethylene oxide) caused by the complexation with poly(acrylic acid)

The complexation between poly(ethylene oxide) (PEO) and poly(acrylic acid) (PAA) was made by using double the molar quantity of either polymer component at pH 2 where the resulting complex completely precipitates. After the removal of the precipitate, PEO or PAA remaining in the supernatant was subjected to gel permeation chromatography to investigate the change in the molecular weight distribution (MWD) caused by the complexation. No remarkable difference is observed in the MWD curves for PEO[1] (M_w=1.37 × 10⁴) before and after the complexation with PAA[1] (M_w=1.10 × 10³) and PAA[2] (M_w=4.16 × 10⁵). However, the MWD curves of PEO[2] (M_w=1.26 × 10⁵) and PAA[2] become shortened and shift to the low molecular weight side after the complexation with PAA[1] or [2] and PEO[2], respectively. This tendency is enhanced by increasing the complexation temperature. From these results, it is indicated that the complexation between PEO and PAA deals with an equilibrium reaction, and the equilibrium constant is dependent on the chain length of both polymer components and also on the complexation temperature.     

Gel chromatographic investigation of p-benzoquinone and styrene products copolymerized in the presence of BF3·OEt2

The molecular weight distribution of copolymers of p-benzoquinone and styrene was studied by g.p.c.. It was shown that the products synthesized have low molecular weights and narrow MWD. p-Benzoquinone was found to be a copolymer macromolecule regulator.     

气升式内环流反应器中油滴的分散特性

本文研究了气升式内环流反应器中油滴的分散特性。以对数正态分布密度函数为油滴尺寸的分散模型,导出了油滴的Sauter平均直径解析式。对模型作了实验验证,关联了模型参数。提出了油滴的尺寸分布密度函数和Sauter平均直径的半经验式。结果表明计算值与实验值吻合良好。     

PAIDD: a hybrid P2P-based architecture for improving data distribution in social networks

Rapid growth in social networks(SNs)presents a unique scalability challenge for SN operators because of the massive amounts of data distribution among large number of concurrent online users.A request from any user may trigger hundreds of server activities to generate a customized page and which has already become a huge burden.Based on the theoretical model and analytical study considering realistic network scenarios,this article proposes a hybrid P2P-based architecture called PAIDD.PAIDD fulfills effective data distribution primarily through P2P connectivity and social graph among users but with the help of central servers.To increase system efficiency,PAIDD performs optimized content prefetching based on social interactions among users.PAIDD chooses interaction as the criteria because user’s interaction graph is measured to be much smaller than the social graph.Our experiments confirm that PAIDD ensures satisfactory user experience without incurring extensive overhead on clients’network.More importantly,PAIDD can effectively achieve one order of magnitude of load reduction at central servers.     

湛江电网故障统计分布及台风演化分析

研究湛江电网故障统计分布规律,发现湛江电网故障具有明显的幂律特性,去除故障极值日的数据呈指数分布.而故障极值日均伴有极端天气,表明湛江电网故障的幂律特性因极端天气引发.     

10kV配网自动化系统建设与规划

介绍10kV配网自动化系统建设与规划的主要内容,并提出注意事项。     

不同线密度粘胶原丝及其碳纤维的结构性能对比

用Weibull分析处理 10mm长的 4种不同线密度粘胶原丝和相应碳纤维的单丝断裂强度 ,得到原丝线密度、强度分布和碳纤维强度的对应关系。采用透射电镜 (TEM )和小角X散射 (SAXS)分析粗旦原丝 ,发现孔洞较多 ,并存在大于 70nm的大孔洞。截面和表面照片也揭示出细旦原丝截面相对规整 ,表面较光滑 ,粗旦原丝则反之。结果表明 ,原丝线密度小 ,截面形状圆整 ,缺陷少 ,所制得的碳纤维强度高。     

Structural characterization of 1,2-polybutadiene by 13C-n.m.r. spectroscopy: 2. Sequence distribution of 1,2-unit in hydrogenated polybutadienes

The configurational sequences of 1,2-unit in a series of hydrogenated syndiotactic 1,2-polybutadienes were determined in relation to the sequence distribution of 1,2- and 1,4-units on the basis of the ¹³C-n.m.r. signal assignment of the methyl carbons. The observed triad distributions of 1,2- and 1,4-units and configurational distributions of the 1,2-unit are in good agreement with the calculated distributions from transition probabilities. The number average sequence lengths of the 1,2-unit and the 1,2-unit in the racemic addition are 5.7 to 8.0 and 4.1 to 5.4, respectively. From the extrapolation of the plot of the number average sequence length against the crystallinity of the starting 1,2-polybutadienes, the minimum sequence length for crystallization is estimated to be 3.7 for the 1,2-unit in the racemic addition.