Classical and Bayesian Inference of an Exponentiated Half-Logistic Distribution under Adaptive Type II Progressive Censoring

The point and interval estimations for the unknown parameters of an exponentiated half-logistic distribution based on adaptive type II progressive censoring are obtained in this article. At the beginning, the maximum likelihood estimators are derived. Afterward, the observed and expected Fisher’s information matrix are obtained to construct the asymptotic confidence intervals. Meanwhile, the percentile bootstrap method and the bootstrap-t method are put forward for the establishment of confidence intervals. With respect to Bayesian estimation, the Lindley method is used under three different loss functions. The importance sampling method is also applied to calculate Bayesian estimates and construct corresponding highest posterior density (HPD) credible intervals. Finally, numerous simulation studies are conducted on the basis of Markov Chain Monte Carlo (MCMC) samples to contrast the performance of the estimations, and an authentic data set is analyzed for exemplifying intention.     

Plastically deformable polyethylene with excellent transparency and stress whitening resistance properties fabricated by constructing massive chain entanglement

Stress whitening is one of the most prominent macroscopic defects for polyethylene (PE), which greatly affects the appearance and quality of its commodity. In order to eliminate the stress whitening defects of PE, ultrahigh molecular weight polyethylene (UHMWPE) was blended with PE to fabricated PE/UHMWPE, and the enhanced intermolecular entanglement and stretchability was achieved, which greatly suppressed and impeded the occurrence of heterogeneous plastic deformation and fibrillar bundle structure during applying tensile stress, resulting in the sharply deceased of the nanoscale cavities defects for the sample. And thus, the elimination of stress whitening defects and high-light transmittance in the visible region with excellent optical transparency performance were successfully achieved for PE/UHMWPE. Moreover, introduction of UHMWPE chains significantly improved the orientation degree and formed a dense oriented crystalline network with fine lamellae for the sample, which highly enhanced the mechanical strength of PE/UHMWPE after applying stress. This work provided a new strategy for developing stress whitening eliminating polyolefin materials with high performance, which was of great significance for sustainable development and environmental friendliness.     

Photo-Induced Self-assembly of Copolymer-Capped Nanoparticles into Colloidal Molecules

Colloidal molecules (CMs) are precisely defined assemblies of nanoparticles (NPs) that mimic the structure of real molecules, but externally programming the precise self-assembly of CMs is still challenging. In this work, we show that the photo-induced self-assembly of complementary copolymer-capped binary NPs can be precisely controlled to form clustered AB _x or linear ( AB ) _y CMs at high yield (x is the coordination number of NP- B s, and y is the repeating unit number of AB clusters). Under UV light irradiation, photolabile p-methoxyphenacyl groups of copolymers on NP- A *s are converted to carboxyl groups (NP- A ), which react with tertiary amines of copolymers on NP- B to trigger the directional NP bonding. The x value of AB _x can be precisely controlled between 1 and 3 by varying the irradiation duration and hence the amount of carboxyl groups generated on NP- A s. Moreover, when NP- A * and NP- B are irradiated after mixing, the assembly process generates AB clusters or linear ( AB ) _y structures with alternating sequence of the binary NPs. This assembly approach offers a simple yet non-invasive way to externally regulate the formation of various CMs on demand without the need of redesigning the surface chemistry of NPs for use in drug delivery, diagnostics, optoelectronics, and plasmonic devices.     

二元共组装法制备无裂痕反蛋白石结构薄膜的研究

近年来,由于在光学、电学和生化等领域具有广泛的潜在应用,有序多孔反蛋白石结构薄膜的研究引起了人们的广泛关注.但是其在制备过程中常常会形成一些无法控制的缺陷,限制了这类材料的普及和实际应用.通过使用两种基质前驱体（正硅酸乙酯或丝素蛋白）与胶体小球混合共组装,探究了二元体系共组装法制备无裂痕反蛋白石结构薄膜的可行性.并用扫描电镜和可见光谱对薄膜结构进行了表征.结果表明,对于正硅酸乙酯体系,在不影响胶体小球有序排列的条件下,正硅酸乙酯在小球间的空隙中发生溶胶凝胶转变,与微球共同组装成有序致密的整体,去除微球模板后,可以得到大规模（>200 μm）无缺陷有序的反蛋白石结构薄膜.而对于大分子丝素蛋白体系,由于它和胶体小球有较强的相互作用力,会抑制胶体小球的有序组装,导致无法形成有序结构薄膜.对两种二元共组装体系进行了实验探索,实验结果不仅有助于人们了解共组装方式的适用范围,而且为设计和制备无缺陷反蛋白石薄膜提供了新的途径.     

Research on the resolution of micro stereo lithography

Micro stereo lithography is a kind of technology utilizing the solidified effect that photo curable polymer will appear under ultraviolet （UV） laser exposure. It is widely used in three-dimensional （3D） micro fabrication. We get the experimental values of a pair of UV laser curing coefficients, absorption coefficient and critical curing energy, of curable resin by fitting the calculation results of the Gaussian beam theory and experimental curing results. The theoretical relation between the curing unit＇s shape and the exposure features of time and intensity of convergent Gaussian beam is presented. The calculation and experimental results of curing unit under different conditions agree well with each other. This research offers a steady base for further research about the improvement of resolution.     

Polarization storage by two-photon-induced anisotropy in bisazobenzene copolymer film

A copolymer containing bisazobenzene chromophores, poly[(methylmethacrylate)-co-4-{(2-methacryloyloxyethyl)oxy}-4′-(4-nitro-phenylazo)azobenzene)] (poly(MMA-co-M2BAN)), was synthesized and used for two-photon-induced polarization storage. Based on two-photon-induced optical anisotropy resulting from photoselective isomerization of bisazochromophores, the data have been recorded by linearly polarized Ti:Sapphire laser (wavelength: 800 nm, pulse duration: 80 fs, and repetition rate: 80 MHz) and read by reflection confocal laser scanning microscope. The recorded bits are dark dots when the polarization of the reading beam is parallel to the recording beam, but the recorded bits become bright dots when the polarization of the reading beam is perpendicular to the recording beam. Two letters can be encoded in the same region of a given layer by separating the two polarization directions of recording beams at an angle of 45°. The relationships between the readout intensity of the recorded bits and the recording power under two different readout modes were investigated and the results showed that there are two opposite change trends for parallel readout and perpendicular readout, respectively, and the readout threshold value is around 12 mW.     

Delay-dependent stability of symmetric schemes in Boundary Value Methods for DDEs

We consider the symmetric schemes in Boundary Value Methods (BVMs) applied to delay differential equations y^′(t)=ay(t)+by(t-τ) with real coefficients a and b. If the numerical solution tends to zero whenever the exact solution does, the symmetric scheme with (k₁+m,k₂)-boundary conditions is called τ_k1,k2(0)-stable. Three families of symmetric schemes, namely the Extended Trapezoidal Rules of first (ETRs) and second (ETR₂s) kind, and the Top Order Methods (TOMs), are considered in this paper.By using the boundary locus technology, the delay-dependent stability region of the symmetric schemes are analyzed and their boundaries are found. Then by using a necessary and sufficient condition, the considered symmetric schemes are proved to be τ_ν,ν-1(0)-stable.     

一类连续可分离背包问题的直接算法

对于一类带有单个线性约束以及盒约束的一般连续可分离二次背包问题给出了一种直接的算法,根据模型特有的结构,通过调节线性约束的拉格朗日乘子λ 的取值范围,以及在算法求解过程中通过判断目标函数一次项中的变量是否在盒约束范围内,来逐步确定所有变量的最优值, 并通过该算法得到的实验结果与其他算法的比较,说明了这种算法的可行性和有效性．     

钯催化偶联反应合成刚性桥连的苯并菲盘状液晶二聚体

盘状液晶是一类新型有机半导体材料, 盘状二聚体具有新颖的自组织特性. 合成了一系列官能化的盘状液晶单体, 再通过Pd催化端炔自身偶联反应合成了六个二苯基丁二炔桥连的苯并菲盘状液晶二聚体: (RO)₅C₁₈H₆(O₂CC₆H₄C≡C—C≡CC₆H₄CO₂)C₁₈H₆(OR)₅ (R＝C_nH_2n＋1, n＝4～9). 化合物的纯度和结构通过¹H NMR, IR和高分辨质谱表征. 二聚体的热失重分析(TGA)结果显示它们有良好的热稳定性, 在370 ℃才开始分解. 化合物的热致液晶性通过偏光显微镜和差视扫描热量法研究, 结果显示所有单体及二聚体化合物均为柱状相液晶, 在室温及以下仍处于液晶相. 单体清亮点随柔链增长呈下降趋势, 而二聚体呈相反趋势. 苯并菲柔链长度和连接基刚性对液晶性都有重要影响.     

鼓泡流化床中流动特性的多尺度数值模拟

鼓泡流化床因其较高的传热特性以及较好的相间接触已经被广泛应用于工业生产中,而对鼓泡流态化气固流动特性的充分认知是鼓泡流化床设计的关键.在鼓泡流化床中,气泡相和乳化相的同时存在使得床中呈现非均匀流动结构,而这种非均匀结构给鼓泡流化床的数值模拟造成了很大的误差.基于此,以气泡作为介尺度结构,建立了多尺度曳力消耗能量最小的稳定性条件,构建了适用于鼓泡流化床的多尺度气固相间曳力模型.结合双流体模型,对A类和B类颗粒的鼓泡流化床中气固流动特性进行了模拟研究,分析了气泡速度、气泡直径等参数的变化规律.研究表明,与传统的曳力模型相比,考虑气泡影响的多尺度气固相间曳力模型给出的曳力系数与颗粒浓度的关系是一条分布带,建立了控制体内曳力系数与局部结构参数之间的关系.通过模拟得到的颗粒浓度和速度与实验的比较可以发现,考虑气泡影响的多尺度曳力模型可以更好地再现实验结果.通过A类和B类颗粒的鼓泡床模拟研究发现,A类颗粒的鼓泡床模拟受多尺度曳力模型的影响更为显著.