垃圾填埋渗滤液溶解性有机物组分的光谱学特性研究

选取3个不同填埋年限的渗滤液样品,以Leenheer的分组方法为基础,采用XAD-8树脂将渗滤液中的溶解性有机物(DOM)按极性和电荷特性分为结构较为均一的不同组分,用荧光光谱和紫外光谱对其中3个组分进行分析。荧光光谱分析表明,填埋初期,疏水酸性组分(HOA)、疏水中性组分(HON)和亲水性组分(HIM)均以类蛋白物质为主,随着填埋年限增加,其分子复杂化程度增强;其中HOA组分分子量最大、复杂程度最高,同时芳烃化合物的含量也最高,HON居中,HIM组分最小。紫外光谱分析表明,HOA和HON组分芳香环上的取代基均以羰基、羧基、羟基为主;而HIM组分则以脂肪链为主,同时芳香烃化合物含量较低。研究结果表明,随着填埋年限的增加,三种组分的复杂化程度均呈上升趋势。     

Preparation of Silica Aerogel/Resin Composites and Their Application in Dental Restorative Materials

As the most advanced aerogel material, silica aerogel has had transformative industrial impacts. However, the use of silica aerogel is currently limited to the field of thermal insulation materials, so it is urgent to expand its application into other fields. In this work, silica aerogel/resin composites were successfully prepared by combining silica aerogel with a resin matrix for dental restoration. The applications of this material in the field of dental restoration, as well as its performance, are discussed in depth. It was demonstrated that, when the ratio of the resin matrix Bis-GMA to TEGDMA was 1:1, and the content of silica aerogel with 50 μm particle size was 12.5%, the composite achieved excellent mechanical properties. The flexural strength of the silica aerogel/resin composite reached 62.9546 MPa, which was more than five times that of the pure resin. Due to the presence of the silica aerogel, the composite also demonstrated outstanding antibacterial capabilities, meeting the demand for antimicrobial properties in dental materials. This work successfully investigated the prospect of using commercially available silica aerogels in dental restorative materials; we provide an easy method for using silica aerogels as dental restorative materials, as well as a reference for their application in the field of biomedical materials.     

Py-GC/MS分析技术与其在烟用中草药添加剂中的应用

通过热裂解实验,可以更加深入地了解卷烟燃吸过程中各个燃烧条件和整个烟气化学的关系,还可对不同温度下的裂解产物和作用机理进行研究。本文综述了裂解-气相色谱/质谱法在烟用中草药添加剂研究中的应用。     

Performance of La2O3/InAlN/GaN metal—oxide—semiconductor high electron mobility transistors

We report on the performance of La2O3/InAlN/GaN metal-oxide-semiconductor high electron mobility transistors(MOSHEMTs) and InAlN/GaN high electron mobility transistors(HEMTs).The MOSHEMT presents a maximum drain current of 961 mA/mm at Vgs = 4 V and a maximum transconductance of 130 mS/mm compared with 710 mA/mm at Vgs = 1 V and 131 mS/mm for the HEMT device,while the gate leakage current in the reverse direction could be reduced by four orders of magnitude.Compared with the HEMT device of a similar geometry,MOSHEMT presents a large gate voltage swing and negligible current collapse.     

求解Euler方程的区域分解方法与并行算法

将复杂形状区域划分成多块子区域,研究发展了一种多块区域之间迎风守恒型的内边界耦合方法,实现相邻子区域解的光滑过渡,使多区耦合得到总体流场的数值解。对二维翼型跨音速流动和圆弧形隆起物超音速流动等进行了分区数值计算,并将计算结果与单区计算结果和实验结果作了比较。并行分区计算引入"先进先出"的同步控制等待机制,实现了高效率并行计算,还分析了影响并行效率的主要因素。     

低气压条件下氢气潘宁放电的模拟分析

为更好地理解低气压、弱电离条件下潘宁离子源放电过程中离子和电子的动力学行为, 通过建立二维轴对称模型, 采用粒子模拟与蒙特卡罗相结合(PIC/MCC)的方法, 考虑了电子与氢气之间的弹性碰撞、激发、电离以及氢原子、离子之间的弹性碰撞和电荷交换等过程, 对微型氢气潘宁离子源放电和引出过程进行了数值研究. 考察了磁场位形、壁面二次电子发射系数、引出电压和充气压力对放电过程的影响, 得到了实验中难以诊断得到的放电腔内电子与离子数密度分布, 阳极电流、引出极离子电流、单原子氢离子比例和双原子氢离子比例等宏观参数与实验结果相一致. 通过仿真使得对氢气潘宁放电机制的研究从定性过渡到定量, 这对于潘宁离子源的设计和改进具有重要意义. 关键词： 潘宁放电 氢气 粒子模拟 蒙特卡罗     

不同类型细胞穿膜肽二级结构特征研究

细胞穿膜肽是一类能以受体依赖或非受体依赖方式介导胞吞作用的小分子短肽,能够携带不同分子穿过细胞膜,这一特性使细胞穿膜肽成为一种有效的运输载体,为药物靶向治疗提供了新希望.本文从生物信息角度针对不同长度区间、运输不同类型分子细胞穿膜肽之间的异同二级结构特征进行了系统研究,同时进一步对不同穿膜方式对应的细胞穿膜肽二级结构特征进行了对比研究,结果表明不同类型细胞穿膜肽之间在二级结构组成上具有不同程度差异特征,为今后揭示细胞穿膜肽相关分子结构机制奠定可靠的理论基础.     

HSH-carbon: A novel sp2−sp3 carbon allotrope with an ultrawide energy gap

An sp²-sp³ hybrid carbon allotrope named HSH-carbon is proposed by the first-principles calculations. The structure of HSH-carbon can be regarded as a template polymerization of [1.1.1]propellane molecules in a hexagonal lattice, as well as, an AA stacking of recently reported HSH-C₁₀ consisting of carbon trigonal bipyramids. Based on calculations, the stability of this structure is demonstrated in terms of the cohesive energy, phonon dispersion, Born−Huang stability criteria, and ab initio molecular dynamics. HSH-carbon is predicted to be a semiconductor with an indirect energy gap of 3.56 eV at the PBE level or 4.80 eV at the HSE06 level. It is larger than the gap of Si and close to the gap of c-diamond, which indicates HSH-carbon is potentially an ultrawide bandgap semiconductor. The effective masses of carriers in the VB and CB edge are comparable with wide bandgap semiconductors such as GaN and ZnO. The elastic behavior of HSH-carbon such as bulk modulus, Young’s modulus and shear modulus is comparable with that of T-carbon and much smaller than that of c-diamond, which suggests that HSH-carbon would be much easier to be processed than c-diamond in practice.     

Bioactive Components and Anticancer Activities of Spray-Dried New Zealand Tamarillo Powder

Tamarillo fruit contains many phytochemicals that have beneficial therapeutic and nutritional properties. Spray-drying is widely used to preserve fruit puree in powder form. However, to obtain high-quality fruit powder, the optimisation of spray-drying conditions is necessary, as a high drying temperature can damage sensitive bioactive compounds. This study investigated the effects of spray-drying on the microstructure, polyphenolics, total flavonoids, total carotenoids, antioxidant activity, and anticancer capacity of tamarillo powder. Response surface methodology (RSM) was used to optimise the spray-drying process to produce tamarillo powder. The independent variables were inlet drying temperature (120–160 °C), flow rate (1–5 g/mL), and maltodextrin concentration (0–10%). These variables influenced the microstructural attributes, bioactive components, and cytotoxicity of the spray-dried tamarillo powder. The increase in polyphenols and antioxidant activities were favoured under high-temperature spray drying conditions and a low carrier concentration. The optimised spray-drying conditions for producing tamarillo powder with high antioxidant and anticancer activities, high yield, and stable bioactive compounds were found to be at 146.8 °C inlet temperature, and a flow rate of 1.76 g/mL.