氯苯标准气体的研制

介绍了氮气中氯苯标准气体的研制方法。氯苯标准气体所采用制备方法为称量法,分析方法为GC-FID法。实验结果显示,氯苯标准气体具有良好的线性、瓶内均匀性和稳定性,有效期为12个月。研究制备的氯苯标准气体标准值为1~5μmol/mol,相对扩展不确定度为5%（置信度为95%）,与美国Scott Specialty Gases的同类标准气体具有可比性。     

Effect of Dosage on the Conduction of Electron Beam Cross-Linked Thermoplastic Elastomeric Films from Blend of LDPE and EVA Copolymer

The effect of electron beam irradiation at different radiation doses (50, 100, 150, 200, and 300 kGy) on Low-density polyethylene/ethylene-vinyl acetate copolymer (LDPE/EVA) blend was investigated. Measurements of I-V characteristics have been carried out at room temperature. It was found that the β parameter increases with the doses. This feature was attributed to the differences in electrical conductivity of the materials. The conduction mechanism is discussed qualitatively on the basis of Poole-Frenkel conduction mechanisms (enhanced conductivity at high electric fields due to the lowering of the potential barrier), also, at low-voltage region conduction was discussed in terms of the Schottky conduction mechanism namely β_s (Schottky field-lowering coefficient). The value of the Poole-Frenkel high field-lowering coefficient β_PF increases with increasing voltage range. Both mechanisms are related and display a highly consistent response to electron beam exposure.     

Nanodots of multiferroic oxide material BiFeO3 from the first Principles

Multiferroic nanodots can be harnessed to aid the development of the next generation of nonvolatile data storage and multi-functional devices. In this paper, we review the computational aspects of multiferroic nanodot materials and designs that hold promise for the future memory technology. Conception, methodology, and systematical studies are discussed, followed by some up-to-date experimental progress towards the ultimate limits. At the end of this paper, we outline some challenges remaining in multiferroic research, and how the first principles based approach can be employed as an important tool providing critical information to understand the emergent phenomena in multiferroics.     

Impact of β-Sheet Conformations on the Mechanical Response of Protein in Biocomposites

Proteins in biological nanocomposites play an important role in their mechanical response. Proteins in nacre, the inner layer of seashells, have been shown to have exceptional mechanical properties. One of the important nacre proteins, Lustrin-A, has abundance of polypeptides in zig-zag conformation called β-sheets. β-sheets of protein when present close to each other in multiple numbers could take the shape of a planar β-sheath like structure or a β-barrel to form a domain. In natural proteins both these types of structures are commonly found. However, the conformation of β-sheets in Lustrin-A is not known at this time. Effort has been made through this work to study the mechanical response of these β-planar sheath and β-barrel structures when subjected to external loads. Comparative study of the stress-deformation characteristics of these two types of structures has been made. Both these structures with almost similar number of amino acids have been extracted from one single spinach protein: Ferredoxin Reductase (1FNR). Steered molecular dynamics has been used to conduct these studies. The article deals with the separation of the two domains from the main protein, simulation details, and results comparing the responses.     

Evaluation of critical formulation factors in the development of a rapidly dispersing captopril oral dosage form

New methods of manufacture have enabled the creation of novel dosage forms with unique rapid-dispersion properties. This study combines one such technique with a statistical experimental design to develop dosage forms from captopril, an angiotensin-converting enzyme inhibitor used to treat cases of hypertensive emergency. The TheriForm™ process, a novel microfabrication technique, was used to build the dosage forms in a layer-by-layer fashion. Three key formulation factors were chosen for the design of experiments. A modified central composite design (Box-Behnken design) was used to maximize the efficiency of the experiments. A total of 13 distinct formulations were fabricated and tested, using mannitol as the bulk excipient. In addition, three replicates of the center point were tested to assess variability and experimental error. These formulations were tested for speed of dispersion (flash time), active content, hardness, friability, and moisture absorption. Regression analysis was performed to fit data responses to quadratic equations. Excellent dose accuracy (95% to 102% of target) and content uniformity (between 1.03% to 2.84%) were observed from all experimental formulation batches. As expected, the choice of powder additive (maltitol, maltodextrin, polyvinyl pyrrolidone), level of additive (2.5% to 7.5%), and saturation level of the binder liquid (45% to 65%) were all found to be significant factors for the TheriForm process. The regression analysis suggested that a rapidly dispersing dosage form of optimal physical properties would be obtained when a powder mixture of mannitol (97.5%) and maltitol (2.5%) is used at a saturation level of 45%. In conclusion, rapidly dispersing captopril oral dosage forms were successfully fabricated and tested. A wide range of physical properties, flash time, and hardness, were determined experimentally, and the effects of key formulation factors were identified.     

Evaluation of the Heat Treatment Response of a Multiphase Hot-Rolled Steel Processed by Controlled Rolling and Accelerated Cooling

The tensile properties of hot-rolled multiphase steel after heat treatment were analyzed on a laboratory scale. Subcritical treatments applied to the hot-rolled strip revealed an increase in the yield stress and elongation with increasing temperature. Normalizing of the strip at 920°C notably improved the ductile response, while both the yield stress and the anisotropy of every property evaluated at 0°, 45°, and 90° to the rolling direction in the rolling plane were significantly reduced.     

z向流动RTM工艺树脂的流动浸润行为

研究了层间“离位”附载多孔薄膜结构形式增韧层的大厚度纤维预成型体中等代流体（树脂）沿预成型体厚度方向（z向）的流动行为,通过压力传感器监测z向流动RTM（z-RTM）工艺注射过程中进、出胶口压力的变化规律,进一步反推树脂在层间“离位”增韧与非增韧预成型体中的宏观流动及微观浸润模式。结果表明,在 z-RTM工艺注射过程中,树脂在沿纤维束间z向快速流动的同时完成对纤维丝束内部的浸润。层间“离位”附载的增韧层虽延缓了树脂的宏观流动,但使流动前锋曲面更加平滑。层间“离位”增韧预成型体z向渗透率为3.5×10^-15m²,与非增韧预成型体的z向渗透率2.9×10^-14m²相比,降低约一个数量级。     

Performance of multilayered particles: influence of a thin cushioning layer

Nowadays, oral dosage forms with controlled release kinetics have known an increasing interest. The polymer coating of drug-loaded particles is one of the most common methods used for controlling drug delivery. Such multilayered particles could be either filled into capsules or compressed into tablets for their oral administration. However, many studies have noticed that coating films are damaged during the compression process, leading to significant changes in drug release profiles. The aims of this study were to investigate the effects of a thin cushioning layer [made of HydroxyPropylMethyl Cellulose (HPMC)] applied on coated theophylline particles upon particle characteristics, tablet properties, and then upon their dissolution performance. If no significant effect was shown with particles, this thin HPMC layer played an important role in the tablets. Tablet cohesiveness was decreased due to HPMC cushioning properties and moreover, the theophylline release rate was increased, as HPMC is a water-soluble polymer creating channels in polymer film for dissolution medium. Therefore, a cushioning layer helped to protect polymer coats from fracture during compression but could also affect drug release and so, both effects must be checked in such a drug delivery system.     

克伦特罗残留检测免疫芯片的研制

为实现克伦特罗残留的规模检测设计其残留检测的免疫芯片。以玻片为载体并对玻片表面进行APTES-DGA化学修饰,将克伦特罗抗体偶联至玻片表面, 以牛血清白蛋白封闭玻片表面活性基团,加待测品和标样,标样中辣根过氧化酶标记的克伦特罗和待测品中的克伦特罗与克伦特罗抗体竞争性结合,借助辣根过氧化酶催化化学发光反应并检测光信号值,检测过程中考查加样体积、温育温度、温育时间、洗液浓度及化学发光积分时间等对检测结果的影响,检测方法学试验中考查检出限、定量限、线性和回收率等指标。结果显示：通过APTES-DGA修饰载玻片具有较好的信号均一性和抗体偶联能力,检测过程中加样体积为50 μL、温育温度为37 ℃、温育时间为30 min、洗液浓度为10倍稀释液、化学发光积分时间为60 s具有较稳定的检测结果。本法研制的免疫芯片检测克伦特罗残留快速、简单、准确。     

Mg-α-SiAlON/MgO复合材料中Mg-α-SiAlON的原位合成

为改善低品位Mg基材料高温性能,采用烧结Mg砂、金属Al粉、单质Si粉和Al₂O₃粉为主要原料,制备了Mg-α-SiAlON/MgO复合材料。通过XRD、SEM及EDS等检测手段,研究了不同原料质量分数及氮化温度条件下Mg-α-SiAlON/MgO复合材料中Mg-α-SiAlON的原位合成,结合热力学分析确定了合成Mg-α-SiAlON的气氛条件并分析了合成Mg-α-SiAlON的反应机制。结果表明：1 550℃时的氮、氧分压满足合成Mg-α-SiAlON的热力学条件。当烧结Mg砂粉、Al粉、Si粉和Al₂O₃粉的质量分数之和为40wt%时,1 550℃保温3 h氮化后的Mg-α-SiAlON/MgO复合材料中板片状Mg-α-SiAlON相生成量最高可达32.1%,且相互交错构成骨架,将低熔点物相包裹其中。利用烧结Mg砂原位氮化制备Mg-α-SiAlON/MgO复合材料,有利于提高Mg基材料的抗热震性能。     

Effect of tocopheryl polyethylene glycol succinate on the percutaneous penetration of minoxidil from water/ethanol/polyethylene glycol 400 solutions

We described to achieve the local retention of minoxidil which has penetrated the skin with minimization of its absorption into the general circulation and elimination of local irritation induced by propylene glycol. The effect of tocopheryl polyethylene glycol succinate (TPGS) on the penetration flux of minoxidil and its retention in the skin from topical minoxidil formulations consisting of water, alcohol, and polyethylene glycol 400 was characterized by an experimental design of ten solvent formulations in this study. Results show that the addition of TPGS was only able to improve the solubility of minoxidil in those solvent systems containing higher proportions of water and PEG 400, and the extent of improvement was also more profound with the addition of TPGS at concentrations higher than 5%. For those solvent systems containing a higher fraction of alcohol, an insignificant change in minoxidil solubility with increasing added amounts of TPGS was noted even with the tendency to decrease the solubility of minoxidil with higher amounts of TPGS. Increasing the amount of TPGS added gradually increased the flux and the corrected flux from solvent formulations with a lower solubility parameter, but decreased those from solvent systems with a higher solubility parameter. With the addition of TPGS, solvent formulation F6 (alcohol:PEG 400 of 50:50) was demonstrated to be the optimal choice by having an improved local effect and a reduced systemic effect compared to the reference of 2% Regaine®. Tocopheryl polyethylene glycol succinate (TPGS) was mainly retained locally in the stratum corneum, and the amount was proportional to the increase in the amount of TPGS added to these ten solvent formulations.     

概论包装整体系统化设计

从适应市场和人们不断提高消费需求的角度,宏观论述包装整体系统化设计与时代要求,分析课题调研、策划在设计中的关系与地位,讨论包装整体系统化设计的基本程序原则与必然趋势。     

超声辅助制备β-磷酸三钙/Mg-Zn-Ca生物复合材料及性能

在生物Mg合金基体中添加β-磷酸三钙（β-TCP）颗粒可以调控其力学性能及腐蚀降解性能,满足人体不同植入部位的服役需求。本研究在机械搅拌铸造的基础上,采用超声方法对Mg基复合材料的熔体进行辅助处理,制备了β-TCP添加量为1%（质量比）、Zn含量为3%（质量比）、Ca含量为0.2%（质量比）的β-TCP/Mg-Zn-Ca可降解生物复合材料,对超声处理制备的β-TCP/Mg-Zn-Ca复合材料的显微组织、力学性能和腐蚀行为与未超声处理制备的β-TCP/Mg-Zn-Ca复合材料进行了对比研究。结果表明：超声处理可以细化β-TCP/Mg-Zn-Ca复合材料的显微组织,有利于β-TCP复合颗粒的均匀分散;β-TCP/Mg-Zn-Ca复合材料在模拟体液环境下的耐蚀性得到提高;其屈服强度、抗拉强度和伸长率分别为211.54 MPa、334.32 MPa和7.28%,与未超声处理的β-TCP/Mg-Zn-Ca复合材料相比,分别提高了8.44%、4.67%和17.99%。     

TiO2对琼胶-κ-卡拉胶膜性能的影响

采用热铸法,制备了琼胶膜、κ-卡拉胶膜及其两者的共混膜,并在共混膜中添加质量分数为0.8%的TiO₂粉末,制得TiO₂/琼胶-κ-卡拉胶复合膜。对这4种膜的SEM、XRD、力学性能、透光率、不透明度和对水的阻抗性进行测试。结果表明：琼胶-κ-卡拉胶膜的力学性能、透光率、不透明度和对水的阻抗性均介于琼胶膜和κ-卡拉胶膜之间,琼胶和κ-卡拉胶之间有良好的共混性,并且在共混膜中形成了分子间作用力。TiO₂/琼胶-κ-卡拉胶复合膜的拉伸强度（45.44 MPa）比其他3种膜的拉伸强度都大,其中比琼胶-κ-卡拉胶膜的拉伸强度（31.06 MPa）提高46.30%,但断裂伸长率（15.73%）却比其他3种膜的都低,TiO₂与复合膜基质分子间形成强相互作用力,增强复合膜的拉伸强度;在相同波长下,TiO₂/琼胶-κ-卡拉胶复合膜的透光率比其他3种膜都低,在200~400 nm的紫外光区,TiO₂/琼胶-κ-卡拉胶复合膜的透光率明显低于其他3种膜,添加TiO₂的复合膜对紫外光有显著的屏蔽作用,但在600 nm波长处,不透明度（0.96）比其他3种膜都高;TiO₂/琼胶-κ-卡拉胶复合膜对水的阻抗性高于琼胶-κ-卡拉胶膜。     

特种氧化铝生产研究开发现状及其展望

介绍了特种氧化铝的分类、性质及国内外生产规模并分析其迅速发展的原因；重点介绍了特种氧化铝的应用、制备方法和研究进展，并对特种氧化铝的研究开发趋势提出了新的展望。     

Production of Carbopol 974P and Carbopol 971P pellets by extrusion-spheronization: optimization of the processing parameters and water content

Pellets obtained by extrusion-spheronization represent multiparticulate dosage forms whose interest in intestinal drug delivery can be potentiated and targeted through bioadhesive properties. However, adhesion itself makes the process difficult or even impossible. The problem of tackiness encountered with bioadhesive wet masses was previously eliminated by the use of electrolytes such as CaCl₂. This approach is known to reduce the viscosity of polyacrylic acids by disturbing the interactions between carboxylate groups on adjacent polymer molecules, thereby decreasing their bioadhesive properties. The present study aimed at producing pellets containing carbomers without addition of electrolytes in order to maintain their bioadhesive potentiality at its maximum. Carbopol® 974P (10%, 15% and 20%) and Carbopol® 971P (10%) were used in combination with Avicel® PH101. The extrusion speed (30, 45, 60, 90, and 150 rpm), spheronizer speed (350, 700, 960, 1000, and 1300 rpm), spheronization time (5, 10, 15, and 20 minutes) and amount of water (45%, 50%, 54%, and 58%) were optimized in order to obtain the highest yield of spherical pellets ranging 710-1000 µm in diameter. For pellets containing 10%, 15% Carbopol® 974P or 10% Carbopol® 971P and 45% water content, 30 rpm extrusion speed, 960 rpm, and 10 minutes spheronization speed and time led to the highest yields and sphericities, respectively, 72% and 0.91, 67% and 0.78, and 76% and 0.80. Production of pellets with 20% Carbopol® 974P could be achieved through the increase of the water content up to 58% and implementation of 30 rpm extrusion speed, 1300 rpm, and 10 minutes spheronization speed and time. The yield and sphericity were 42% and 0.78 respectively.     

单细胞测序技术的发展

单细胞测序是指在单个细胞的水平上，对其相关组学进行测序分析的一项新技术。单细胞测序不仅能够分析单个细胞蕴含的遗传信息，还能综合评价多细胞异质性的问题，具有广阔的应用前景。在过去的十几年间，单细胞的研究从开始的单个细胞分离、扩增测序，发展到现今的高通量单细胞测序，陆续出现了众多新型、高效率的方法以及平台。综述了单细胞测序的发展进程，讨论了不同方法以及商用平台的优缺点及其适用性，并展望了单细胞测序对生物计量的影响。     

热水预抽提对竹子硫酸盐纸浆无元素氯漂白性能的影响

本文选用箱3种热水预抽提H-因子(0、500和1 000)和合适的蒸煮有效碱用量,得到卡伯值相近(20)的3种竹子硫酸盐纸浆(KP浆);然后,采用DQP(二氧化氯漂、螯合处理、过氧化氢漂)漂序,通过变化二氧化氯用量和过氧化氢用量,对比漂白浆的白度、返黄值、卡伯值降低率、黏度。发现热水预抽提可以提高纸浆漂白过程的卡伯值降低率;相同总有效氯因子下,漂后浆的白度较高,返黄值较低,黏度相近;达到相同白度(85%ISO)可节省约1.4%的总有效氯用量,然而返黄值略高。     

内凹形针尖的拉曼散射增强特性

利用基于时域有限差分法的FDTD Solutions软件建立了镀银膜内凹形钨针尖-玻璃基底仿真模型,在相同条件下对镀金膜内凹形钨针尖-玻璃基底、内凹形钨针尖-玻璃基底模型的近场电场分布进行数值计算,验证了所设计的模型在拉曼散射增强方面的有效性。研究结果表明:在镀银膜内凹型钨针尖-玻璃基底情况下,该结构可产生最大的拉曼增强因子,为105量级。利用中国计量科学研究院的针尖制备装置制备了优化参数的针尖实物,并利用实验室中的TERS测量装置实现了SWCNTs的TERS信号测量,验证了所设计的针尖在拉曼信号测量方面的有效性。     

A study of the spread surface of polymeric dispersions of Eudragit

The rheology of non-Newtonian fluid systems is complex. Their experimental study is difficult because of the existence of many dependent variables. In the present work, a mathematical equation is proposed to calculate the spread surface from a simple viscosimetric study in a theoretical way. It was determined for multiple parameters. The spread surface has to be marked because of its direct relation to the shear stress; this fact enabled us to connect one variable dependent on the compression deformation with another dependent on the shear deformation. At the same time, the viscoelastic phenomenon can be evidenced by applying this mathematical equation.