Two-dimensional MX Dirac materials and quantum spin Hall insulators with tunable electronic and topological properties

We propose a novel class of two-dimensional(2D)Dirac materials in the MX family(M=Be,Mg,Zn and Cd,X=Cl,Br and I),which exhibit graphene-like band structures with linearly-dispersing Dirac-cone states over large energy scales(0.8–1.8 eV)and ultra-high Fermi velocities comparable to graphene.Spin-orbit coupling opens sizable topological band gaps so that these compounds can be effectively classified as quantum spin Hall insulators.The electronic and topological properties are found to be highly tunable and amenable to modulation via anion-layer substitution and vertical electric field.Electronic structures of several members of the family are shown to host a Van-Hove singularity(VHS)close to the energy of the Dirac node.The enhanced density-of-states associated with these VHSs could provide a mechanism for inducing topological superconductivity.The presence of sizable band gaps,ultra-high carrier mobilities,and small effective masses makes the MX family promising for electronics and spintronics applications.     

低临界胶束浓度PEGMA-b-PCL的制备及其 药物缓释性能

以ε-己内酯（ε-CL）为疏水链段,聚乙二醇甲醚甲基丙烯酸酯（PEGMA）为亲水链段,4-氰基-4-[(十二烷基硫基硫羰基)硫基]戊酸（CDPA）为可逆加成-断裂链转移（RAFT）试剂,在以甲苯为溶剂、N2氛围、80 ℃、反应24 h的条件下,通过RAFT聚合法制备了两嵌段聚合物PEGMA-b-PCL。将其自组装为胶束用作纳米药物载体,并以姜黄素（Cur）为胶束负载药物。考察了两嵌段聚合物结构、分子量及分布,表征了胶束载体粒径、形貌,测试了胶束载体的载药和释药性能。结果表明,不同嵌段聚合物相对分子质量范围为478~7318,此类聚合物具有较低的临界胶束浓度（CMC）,在常规条件下（pH=7.4）其范围为0.920~1.600 μg/mL。胶束载体粒径范围为:68.34~186.30 nm。当n(CDPA)∶n(ε-CL)=1∶200时,胶束载药量和包封率最高,可达12.05%和75.26%。在不同pH值环境下,药物缓释性能可达15 d,其中pH=5.0时释药量可达35.38%。     

Effects of Non-Opioid Analgesics on the Cell Membrane of Skin and Gastrointestinal Cancers

Skin and gastrointestinal cancer cells are the target of research by many scientists due to the increasing morbidity and mortality rates around the world. New indications for drugs used in various conditions are being discovered. Non-opioid analgesics are worth noting as very popular, widely available, relatively cheap medications. They also have the ability to modulate the membrane components of tumor cells. The aim of this review is to analyze the impact of diclofenac, ibuprofen, naproxen, acetylsalicylic acid and paracetamol on skin and gastrointestinal cancers cell membrane. These drugs may affect the membrane through topical application, at the in vitro and in vivo level after oral or parenteral administration. They can lead to up- or downregulated expression of receptors, transporters and other molecules associated with plasma membrane. Medications may also alter the lipid bilayer composition of membrane, resulting in changes in its integrity and fluidity. Described modulations can cause the visualization of cancer cells, enhanced response of the immune system and the initiation of cell death. The outcome of this is inhibition of progression or reduction of tumor mass and supports chemotherapy. In conclusion, non-opioid analgesics may be used in the future as adjunctive therapy for the treatment of these cancers.     

Biomimetic Modification of Water-Borne Polymer Coating with Carnauba Wax for Controlled Release of Urea

Benefitting from the special structure of the leaf cuticle layer, plants have natural hydrophobicity and anti-fouling abilities. Inspired by the leaf surface structure, a biomimetic modification strategy was raised to improve the surface hydrophobicity of polyacrylate coating for controlled release fertilizer. Double-layer (polyacrylate and carnauba wax) coated fertilizer was obtained after biomimetic modification. The quality of controlled release fertilizer modified with the carnauba wax was greatly enhanced, and the coating material was effectively saved. The surface appearance of polyacrylate-coated fertilizer was improved for the surface blemish was repaired by the loaded carnauba wax. The characterizations by Fourier transform infrared spectroscopy indicated that the hydrogen bonds were formed between the water-based polyacrylate membrane and the carnauba wax layers. By optimizing the content of polyacrylate and carnauba wax, the release duration of the fertilizer was effectively prolonged, which was improved from 1 month to more than 2 months after the biomimetic modification. Therefore, biological wax as an environmentally-friendly natural material that has showed a broad potential in the application of coated controlled release fertilizer.     

我国混凝土空心砌块节能建筑案例分析

通过我国混凝土空心砌块节能建筑案例分析,提出外保温、内保温、夹芯保温各有优缺点,应因地制宜,依据建筑功能要求采取适合的保温方式,并根据多年的研究和应用实践经验,提出了我国不同气候区域混凝土空心砌块节能建筑的外墙构造设计方案。     

浅谈零缺陷与质量成本

阐述零缺陷在工作中的行动准则和零缺陷管理所要达到的最终目标,分析了零缺陷在实际生产中对质量成本的影响。     

小型无人直升机的纵向横向解耦优化控制

论文根据小型无人直升机的机理建立了数学模型,并在悬停状态下近似线性化,运用Matlab的非线性控制工具箱(NCD)设计了具有很强鲁棒性的控制器,实现了对于小型无人直升机的纵向和横向的解耦控制,仿真结果证明了方法的有效性。     

Performance of Channel-Aware Scheduling Algorithms for HDR-WPAN

In this paper, we consider the performances in terms of system throughput and response time of various channel-aware scheduling algorithms for both MPEG streams and non-MPEG flows in a high-data-rate (HDR) wireless personal area network (WPAN). The algorithms under investigation are the shortest remaining processing time rule, the exponential rule, the modified largest weighted delay first rule, the maximum rate rule, and the proportionally fair rule. Decodability issues are taken care of by means of the frame-decodability aware technique and the burst transfer eligibility decision mechanism. The impacts of a number of factors including deadline and interference-plus-noise level are also examined. The investigations are carried out through extensive ns-2 simulations. Based on the numerical results, we propose a heuristic scheduling algorithm for MPEG streams that outperforms the above algorithms in terms of system throughput. The findings are useful for system designers.     

多通道高速实时数据采集与处理平台的设计

针对红外导引头多元信息探测和实时数据处理要求,设计了基于FPGA和DSP的多通道高速实时数据采集和处理平台;在该平台中,通过FPGA实现了DSP的引导、多通道高速A/D、D/A、大容量存储器(SDRAM和FLASH)和数字I/O等功能模块的无缝链接及逻辑控制;利用时序分配和EDMA(扩展的直接存储器访问)技术以及McBSP(多通道缓冲串口)和HPI(主机口),实现了FPGA和DSP之间实时传输与通信控制;实际应用表明在该平台中A/D与FPGA之间串行传输速率可达20MHz,FPGA与DSP之间串行传输速率可达70MHz,且平台运行稳定、可靠,满足了红外导引头的实时信号处理要求。