逆掩推覆构造水平井井壁稳定性研究

随着石油勘探开发的不断深入,钻井所面对的地质环境日趋复杂,逆掩推覆构造逐渐发展为钻井过程的重要地质对象之一。在剧烈的构造挤压运动下,地层构造应力显著增加,地层主应力规律发生较大变化,较之构造平缓地区,水平井钻井过程中的井壁稳定性存在较大差异。研究逆掩推覆构造地应力的预测方法,根据多孔介质弹性力学理论,建立该构造环境下水平井的井壁稳定分析模型,分析井眼轨迹对井壁稳定性的影响规律,对于该构造区域内水平井的钻井设计具有重要的指导意义。     

口服制剂掩味方法的研究进展

综述了药物掩味方法的研究进展,对不同的技术进行了总结.开发药物制剂时,正确运用这些方法与技术,不影响药物的物理、化学稳定性和生物利用度.     

掩模版表面灰尘检查设备的优化

如今是经济和科技都飞速发展的时代,掩模版应用十分广泛,在涉及光刻工艺的领域都需要使用掩模版,传统的掩模版生产工艺中检测中需要将掩模版利用翻转检查机翻转180°,利用人眼去观察掩模版表面是否有灰尘和杂质,这种当前的检测方式费时费力,加强自动化,不仅可以最大程度消除一些认为因素所造成的误差,利用机器视觉去检测可以大大提高劳动生产率,获得更高的准确度。     

头孢呋辛酯掩味方法及颗粒剂的稳定性研究

制备掩盖头孢呋辛酯苦味的混合物,并用其进一步制成头孢呋辛酯混悬颗粒剂。以Carbopol为载体材料,用溶剂挥发法制备掩味混合物：以口感有无苦味为评价指标,结合体外溶出实验,找出最佳处方;并对最终处方进行稳定性考察。以Carbopo 1934 PNF为载体材料制备的混合物可以掩盖头孢呋辛酯药物的苦味,且体外释放及稳定性均符合要求,其制成的颗粒剂质量合格。     

克拉霉素掩味颗粒的制备及评价

制备克拉霉素掩味颗粒并对其进行评价。通过流化床包衣和造粒工艺制备克拉霉素掩味颗粒。对样品在不同pH溶出介质的溶出度进行分析,通过傅里叶红外光谱、热分析、扫描电镜及X-射线粉末衍射对样品和物理混合物(克拉霉素+卡波姆+邻苯二甲酸羟丙甲基纤维素酯)进行分析,比较两者差异,通过志愿者对掩味效果进行评价。通过该工艺制备的克拉霉素颗粒体外释放度良好,掩味效果优异。制备的克拉霉素掩味颗粒的耐酸性较好,与美国市售制剂相比溶出度相似性较高,并且该工艺能应用于工业化生产。     

我国光掩模玻璃基板的发展现状及趋势

1光掩模玻璃基板的定义及种类 1.1光学掩模的定义及分类 1.1.1光学掩模板的定义 光学掩模板,又称光掩模板、掩模板、掩膜版、光掩膜、光刻掩膜版、光罩等,在薄膜、塑料或玻璃基体材料上制作各种功能图形并精确定位,以便用于光致抗蚀剂涂层选择性曝光的一种结构,是微电子制造中光刻工艺所使用的图形母版.光掩模板应用十分广泛,在涉及光刻工艺的领域都需要使用光掩模板,主要用于集成电路(1C)、平板显示器(FPD)、印刷电路板(PCB)、微机电系统(MEMS)等领域.     

探究反渗透制水工艺在化纤工程中的应用

黏胶纤维行业中的纺丝技术对水质要求较为严格。本文中作者论述了反渗透技术在化纤工程中制水工艺上的设计思路和工程应用实例。探讨了在高硬度、高铁含量的苦成水水质条件下反渗透膜元件的选用和配置;讨论了原水除铁、化学药剂添加等几个关键工艺的比选和对系统稳定性的影响;介绍了工程中的节水措施和产水脱气过程中的防污染措掩。     

聚丙烯酸树脂Ⅳ及其水分散体对替米考星包衣与体外释放研究

使用三种不同的包衣材料,利用流化床对替米考星颗粒进行了掩味包衣,分别考查了包衣替米考星颗粒在胃液以及唾液中的溶出效果并进行了口尝实验,结合扫描电镜对颗粒包衣后表面的形貌进行了细致分析。结果表明,使用溶液-乳液聚合法制备的聚丙烯酸树脂Ⅳ(E100)、水分散体E30DⅡ作为包衣材料掩味效果最好,且包衣后不影响药物在胃中的溶出效果,可以部分取代聚丙烯酸树脂Ⅳ在药物掩味包衣方面的应用。     

恩诺沙星复合掩味微囊的制备及体外评价

采取固体分散技术联合微囊技术制备兽用恩诺沙星复合掩味微囊,考察了其掩味效果;以其在模拟口腔液中的释放度、载药量和包封率为指标,利用单因素实验和正交实验优化制备工艺.结果表明,复合微囊最优制备条件为:海藻酸钠溶液浓度15 g/L,滴加针头孔径1.0 mm,CaCl_2浓度100 g/L,固化时间10 min.该条件下所得复合微囊外观形态良好,载药量为20.3%,包封率为89.8%,平均粒径为273.67μm;微囊在模拟口腔液中30 s的释放度小于猪对恩诺沙星的苦味阈值,有较好的掩味效果.     

中国“差生”在加拿大成“天才”

又是新学期开学的时间，虽然今年教育部确定的开学第一课主题是“幸福”，但还是难掩学生开学不快乐、不幸福的现状。     

头孢呋新酯的合成改进

将头孢呋新钠溶于偶极非质子性溶剂 N,N-二甲基乙酰胺 ( DMAC)溶液中 ,加入三乙胺( Et3N) ,在室温下 ,滴加 1 -乙酰氧 - 1 -溴乙烷 ,高产率合成头孢呋新酯。产品结构用 IR,1H NMR与HPLC验证     

头孢呋辛酯制剂制备技术进展

头孢呋辛酯为临床上广泛使用的第二代口服头孢菌素。介绍了头孢呋辛酯制剂制备技术,包括微粉化技术和超临界流体技术,详细介绍了制粒技术和掩味技术。     

头孢呋辛酯掩味干混悬剂的制备

通过固体分散体技术采用熔融硬脂酸包裹进行掩味,制备出口感较好的干混悬剂,并符合中国药典要求。采用硬脂酸为掩味材料,加热熔融后混入头孢呋辛酯制备成固体分散体,再进行干混悬剂的制备,并对其处方的最佳比例及其它组分的比例进行了实验筛选。结果表明,采用将2∶1的头孢呋辛酯原料加入75℃加热熔融的硬脂酸中,搅拌均匀粉碎后加入1.5%黄原胶,可以很好地掩盖头孢呋辛酯的苦味,同时能符合中国药典对干混悬剂的要求。     

Coprecipitation of Cefuroxime Axetil-PVP composite microparticles by batch supercritical antisolvent process

Batch supercritical antisolvent precipitation (SAS) process was used to coprecipitate Cefuroxime Axetil amorphous (CFA, antibiotic) and Polyvinylpyrrolidone (PVP-K30) for preparing drug-polymer composite particles. Solutions of CFA and PVP-K30 in methanol with overall concentrations of 50-150 mg/ml and polymer/drug ratios of 1/1-4/1 were sprayed into the CO₂ at 70-200 bar and 35-50 °C with drug + polymer solution injection rates of 0.85 and 2.5 ml/min. Spherical particles having mean diameters of 1.88-3.97 μm, distribution ranges of 0.82-9.7 μm (the narrowest distribution) and 0.91-46.64 μm (the broadest distribution) were obtained. Mean particle size was not affected significantly with the change of process parameters. It was only affected by pressure change. On the other hand particle size distribution was affected by pressure, temperature, drug + polymer solution injection rate and concentration. It was observed that temperature and polymer/drug ratio affected the particle morphology most. The drug release rate of SAS-coprecipitated CFA-PVP (1/1) particles was almost 10 times slower than the drug alone. As the ratio of the polymer increased drug release rate also increased due to the wetting effect of PVP.     

Investigation and scale-up of hot-melt coating of pharmaceuticals in fluidized beds

This study was performed to investigate and scale-up the hot-melt coating process in fluidized beds. A series of well-designed experiments was carried out in a pilot scale unit with 20 kg product capacity to investigate the effects of process variables on the efficiency of the coating of Cefuroxime Axetil with stearic acid. Results showed that the efficiency is at the highest when the fluidization air flow rate is adjusted by considering the changes in the amount of materials present in the unit as well as the changes in the terminal velocities of particles during the process.With the objective to scale-up the hot-melt coating process from pilot to production scale, a dynamic thermodynamic model based on conservation equations of mass and energy was developed. Predictive accuracy of the model was assessed by applying it to the pilot scale unit and comparing its predictions with the online measurements taken on the same unit. Results showed that the predictions of the model agree well with the measurements. Utilizing this model and taking several experiments performed in the pilot scale unit as a basis, scaling up of the hot-melt coating process was carried out. Comparisons of the model predictions with the measurements taken on the production scale unit (200 kg product capacity) revealed that the model is able to reproduce the product attributes and the outlet air temperatures across scales. Therefore, it proves to be a promising tool that can be used in the scale-up of the hot-melt coating processes in fluidized beds.     

Synthesis of cyclodextrin‐based polymers and their use as debittering agents

Cyclodextrins (CDs) and their derivatives are used to suppress unpleasant tastes and odors or to achieve a controlled release of certain food constituents. This article describes the synthesis by nonconventional methods of (1) crosslinked, insoluble CD polymers and (2) water‐soluble, CD‐grafted carboxymethylchitosan and carboxymethylcellulose. The CD polymers were obtained by the reaction of β‐CD with one of the following crosslinking agents: epichlorohydrin, diphenyl carbonate, or hexamethylene diisocyanate. Their preparations were usually carried out under high‐intensity ultrasound, which resulted in much shorter reaction times and narrower distributions of particle size (as determined by scanning electron microscopy measurements). A novel, insoluble CD polymer was obtained by reticulation under microwaves of propargyl‐β‐CD with 1,3‐bis(azidomethyl)benzene through Huisgen 1,3‐dipolar cycloaddition. Short columns packed with the insoluble polymers were found to efficiently sequester naringin from aqueous solutions; successively, they could be easily regenerated by a counter‐current ethanol wash that also achieved an excellent recovery of the flavonoid. Differential scanning calorimetry thermograms showed that the crosslinked CD polymers formed inclusion complexes with naringin. The soluble polymers also interacted with bitter flavonoids of citrus fruits (naringin and limonin), as shown by the results of sensorial panel tests, in which they behaved as bitter‐masking agents. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Preparation of bitter taste masked cetirizine dihydrochloride/β-cyclodextrin inclusion complex by supercritical antisolvent (SAS) process

Rapid-disintegrating tablets (RDT) provide many advantages, such as rapid onset of action and assisting those patients who have difficulty swallowing. An important consideration in the formulation of RDT is masking the bitter taste of the drug to ensure patient compliance. The purpose of this study was to evaluate the possibility of inclusion complexation as a means of formulating taste masked cetirizine dihydrochloride (CTZ) rapid-disintegrating tablets. The inclusion complex between CTZ and β-cyclodextrin (β-CD) was prepared using a supercritical antisolvent (SAS) process, where dimethylsulfoxide (DMSO) was used as a liquid solvent and carbon dioxide (CO₂) as a supercritical antisolvent.Compared to large, irregular shaped products of freeze-drying method, small, spherically shaped, uniformly sized CTZ/β-CD inclusion complex products were successfully prepared by the SAS process. Concerning the structure of the complex, space conformation of the phenyl ring and chlorophenyl ring of CTZ in the β-CD hydrophobic cavity was confirmed by nuclear magnetic resonance spectroscopy (¹H NMR) and two-dimensional rotating frame overhauser effect spectroscopy (2D ROESY) studies. The obtained inclusion complex products prepared by both freeze-drying method and SAS process have the same efficacy in regards to dissolution characteristics and show the effective taste masking as compared to pure CTZ and CTZ/β-CD physical mixtures. In addition, the resulting products prepared by SAS process have negligible amount of residual solvent.     

苦瓜甙的微波提取工艺研究

以苦瓜为原料,用微波提取苦瓜中的苦瓜甙,考察了微波提取工艺中苦瓜投料物液比、微波输出功率、提取时间、溶剂用量等对苦瓜甙提取效果的影响,优选出微波提取的工艺方案.实验结果表明,最佳投料物液比1:3785,微波输出功率700 W,最佳提取时间为6 min,溶剂用量22 mL·g-1,浸润水用量6 mL·g-1.将微波技术运用在苦瓜甙的提取过程中,有效地强化了提取过程,缩短了提取时间,减少杂质.     

Comparative study of the autoxidation of TAG containing conjugated and nonconjugated C<Subscript>18</Subscript> PUFA

Four TAG containing linoleate (soybean-TAG), α-linoleate (perilla-TAG), conjugated linoleate (CLA-TAG), and conjugated linolenate (bitter gourd-TAG) were oxidized in the bulk phase at 50°C. The effects of α-tocopherol and Trolox (6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid) on the oxidation of these TAG were also studied. Progress of oxidation was determined by measuring the oxygen consumption, peroxide formation, and polymer formation. The rates of oxygen consumption and polymer formation of bitter gourd-TAG and CLA-TAG were faster than those of perilla-TAG and soybean-TAG, respectively. The present results revealed that the main oxidation products of bitter gourd-TAG and CLA-TAG were dimers and polymers, whereas hydroperoxides were the main products in the oxidation of perilla-TAG and soybean-TAG. These differences in the oxidation of TAG were characterized mainly by oxidation of the main PUFA contained in each TAG, namely, linoleate (56.1%) for soybean-TAG, α-linolenate (54.5%) for perilla-TAG, conjugated linoleate (69.5%) for CLA-TAG, and conjugated linolenate (61.6%) for bitter gourd-TAG, respectively. α-Tocopherol and Trolox inhibited the oxidation of TAG. The inhibitory effect of these antioxidants was more effective against the oxidation of CLA-TAG and bitter gourd-TAG than that of soybean-TAG and perilla-TAG, respectively. This was probably due to the high rate at which the antioxidants inhibited the dimerization and polymerization of CLA-TAG and bitter gourd-TAG.