两端线型双量子点分子Aharonov-Bohm干涉仪电输运

设计一个两端线型双量子点分子Aharonov-Bohm (A-B)干涉仪. 采用非平衡格林函数技术, 理论研究无含时外场作用下的体系电导和引入含时外场作用下的体系平均电流. 在不考虑含时外场时, 调节点间耦合强度或磁通可以诱导电导共振峰劈裂. 控制穿过A-B干涉仪磁通的有无, 实现了共振峰电导数值在0与1之间的数字转换, 为制造量子开关提供了一个新的物理方案. 同时借助磁通和Rashba自旋轨道相互作用, 获得了自旋过滤. 当体系引入含时外场时, 平均电流曲线展示了旁带效应. 改变含时外场的振幅, 实现了体系平均电流的大小与位置的有效控制, 而调节含时外场的频率, 则可以实现平均电流峰与谷之间的可逆转换. 通过调节磁通与Rashba自旋轨道相互作用, 与自旋相关的平均电流亦得到有效控制. 研究结果为开发利用耦合多量子点链嵌入A-B 干涉仪体系电输运性质提供了新的认知. 上述结果可望对未来的量子器件设计与量子计算发挥重要的指导作用.     

Preparation of acid–base bi-functional hydrotalcite based catalyst for converting Vietnamese coconut oil to green hydrocarbons

Acid–base bi-functional hydrotalcite like compounds based on partial incorporation of Al³⁺ into brucite structure of Mg(OH)₂ with various molar ratios were prepared through co-precipitation method. The co-precipitation of the precursors produced precipitations followed by drying at 120 °C for 12 h and calcination in air flow at 500 °C for 6 h to obtain the catalysts (Mg–Al HLCs). Many techniques including XRD, TG–DTA, EDX, NH₃-TPD, CO₂-TPD, GC–MS and XANES were used to characterize and optimize Mg/Al molar ratio based on the thermal stability of the Mg–Al HLCs and their activities in decarboxylation process of coconut oil. The results showed that the best molar ratio of Mg/Al was 3/1 providing a stable hydrotalcite like structure, and the catalyst possessed both acid and base sites on its surface enhancing its activity and selectivity in the decarboxylation process. The catalysts revealed high performance in the decarboxylation process of coconut oil established at 400 °C for 4 h for green hydrocarbons belonging to kerosene fractions.     

24 Y‐chromosomal STR haplotypic polymorphisms for Chinese Uygur ethnic group and its phylogenic analysis with other Chinese groups

The Uygur ethnic minority is the largest ethnic group in the Xinjiang Uygur Autonomous Region of China, and is a precious resource for the study of ethnogeny and forensic biology. Previous studies have focused on the genetic background of the Uygur group, however, the patrilineal descent of the group is still unclear. In this study, we investigated the genetic diversity of 24 Y‐STR loci in the Uygur group and analyzed the population differentiations as well as the genetic relationships between the Uygur group and other previously reported populations using 17 Y‐filer loci. According to haplotypic analysis of the 24 Y‐STR loci in 109 Uygur individuals, 104 different haplotypes were obtained, 99 of which were unique. The haplotypic diversity and discrimination capacity of these 24 Y‐STR loci in Uygur group were 0.9992 and 0.9541, respectively. An additional 7 loci (DYS388, DYS444, DYS447, DYS449, DYS522, and DYS527a,b) showed high genetic diversity and improved the overall discrimination capacity of the 24 Y‐STR system. Pairwise Fst and neighbor‐joining analysis showed that the Uygur group was genetically close to the Han populations from different regions.     

Developmental validation of the AGCU 21+1 STR kit: A novel multiplex assay for forensic application

In this study, we describe the developmental validation assay performed on a novel designed STR multiplex system, AGCU 21+1 STR kit. This kit contains a sex‐determining locus amelogenin and 21 noncombined DNA index system STR loci, that are, D6S474, D12ATA63, D22S1045, D10S1248, D1S1677, D11S4463, D1S1627, D3S4529, D2S441, D6S1017, D4S2408, D19S433, D17S1301, D1GATA113, D18S853, D20S482, D14S1434, D9S1122, D2S1776, D10S1435, and D5S2500. The 21+1 kit was validated by a series of tests including optimized PCR conditions, sensitivity, precision and accuracy, stutter ratio, DNA mixture, inhibitors, and species specificity according to the revised validation guidelines issued by the Scientific Working Group on DNA Analysis Methods (SWGDAM). Our results in this study show that the kit is a useful tool for forensic application.     

Population genetics and forensic efficiency of twenty‐one novel microsatellite loci of Chinese Yi ethnic group

In this study, we investigated polymorphic distributions of allelic frequencies and forensic genetic parameters of 21 novel autosomal microsatellite loci from 110 unrelated healthy individuals of Chinese Yi ethnic group. Expected heterozygosity, power of discrimination, and polymorphic information content ranged from 0.617 to 0.812, 0.777 to 0.936 and 0.560 to 0.790. The microsatellite loci showed high forensic efficiency. The total discrimination power and cumulate probability of exclusion were 0.99999999999999999986902 and 0.999998818, respectively. Locus‐by‐locus allelic frequencies were compared using analysis of molecular variance (AMOVA) method, and the statistically significant differences were observed between Yi group and Russian, Tujia, Kazak, Bai, Ningxia Han, Salar, Tibetan, and Uigur groups at 5, 6, 7, 7, 7, 8, 12, and 13 loci, respectively. The results of genetic distance comparisons, genetic structure analyses, and principal component analysis all indicated that the Yi group showed relatively short genetic relationships with Russian, Salar, and Bai group. The experimental results showed that the 21 loci in the multiplex system provided highly polymorphic information and forensic efficiency for forensic individual identification and paternity testing, also basic population data for population genetics and anthropological research.     

内给电子体对Ziegler-Natta催化剂性能的影响

研究了5种新型内给电子体对Ziegler-Natta催化剂结构和催化性能的影响.结果表明,使用两种不同制备工艺制备的氯化镁载体均为δ晶型,而不同的内给电子体的加入使得催化剂的氯化镁载体具有不同的微晶结构和形态.在催化剂制备阶段中,内给电子体的加入方式对催化剂的性能有很大的影响.在5种内给电子体中,以cis-1,2-环己二甲酸二异丁酯为内给电子体时,催化剂的聚合活性和PP等规度最高,性能与工业催化剂相当;当选用cis-1,2-环己二甲酸二异丁酯为内给电子体,CMMS为外给电子体,硅钛物质的量之比为10及铝钛物质的量之比为100时,催化剂的聚合活性和PP等规度达到最高.     

Crosslinked nanofibrillated cellulose: poly(acrylic acid) nanocomposite films; enhanced mechanical performance in aqueous environments

Nanofibrillated cellulose (NFC) was compounded with poly(acrylic acid) (PAA) via solvent casting. Nanocomposite films were thermally-crosslinked to allow the formation of ester bonds between NFC and PAA, as confirmed by ¹³CNMR and infrared spectroscopy. The network morphology of the cellulose nanofibrils was left intact by the introduction of PAA and crosslinking. Water absorption and swelling was diminished by the introduction of crosslinking, due to the reduced number of vacant hydroxyl and carboxyl groups available to interact with water molecules. Crosslinking with PAA increased the activation energy required for thermal degradation. PAA effectively reinforced NFC, increasing Young’s modulus, tensile strength and glass transition temperature. Crosslinking imparted restraints on segmental motion of polymer chains, further enhancing the thermomechanical properties and retaining elasticity. Wet-strength properties were enhanced due to the reduced hydrophilicity of crosslinked nanocomposite films.     

Stability of solutions of a class of nonlinear fractional diffusion equations with respect to a pseudo‐differential operator

In this paper, we study the forward and the backward in time problems for a class of nonlinear diffusion equations with respect to the pseudo‐differential operator. Herein, we investigate the stability of the solution of the forward problem in relationship with parameters of the pseudo‐differential operator and initial data. Besides, as known, the backward in time problem is instability. Hence, we give a method to regularize the solution of the backward problem in the case of the parameters are perturbed.     

Reproducing kernel approximation in weighted Bergman spaces: Algorithm and applications

In this paper, we present algorithms of preorthogonal adaptive Fourier decomposition (POAFD) in weighted Bergman spaces. POAFD, as has been studied, gives rise to sparse approximations as linear combinations of the corresponding reproducing kernels. It is found that POAFD is unavailable in some weighted Hardy spaces that do not enjoy the boundary vanishing condition; as a result, the maximal selections of the parameters are not guaranteed. We overcome this difficulty with two strategies. One is to utilize the shift operator while the other is to perform weak POAFD. In the cases when the reproducing kernels are rational functions, POAFD provides rational approximations. This approximation method may be used to 1D signal processing. It is, in particular, effective to some Hardy H^p space functions for p not being equal to 2. Weighted Bergman spaces approximation may be used in system identification of discrete time‐varying systems. The promising effectiveness of the POAFD method in weighted Bergman spaces is confirmed by a set of experiments. A sequence of functions as models of the weighted Hardy spaces, being a wider class than the weighted Bergman spaces, are given, of which some are used to illustrate the algorithm and to evaluate its effectiveness over other Fourier type methods.