一款保湿面贴膜的即时功效初步研究

采用配有水分测试探头CM825、色素测试探头MX18的皮肤弹性测试仪Cutometer MPA580,测定在使用一款保湿面贴膜前后及用后5 h内面部皮肤角质层含水量、黑色素含量及弹性的变化,评估面贴膜使用后改善皮肤水分、肤色及弹性的即时功效。结果表明使用该面贴膜有非常明显的即时功效,主要表现在皮肤水分含量较使用前有非常显著的增加（P〈0.05）,测得皮肤黑色素含量也明显降低（P〈0.05）,但弹性无明显增加。     

芳纶标准回潮率测试方法的改进

针对现有GB/T 6503—2008测试纤维回潮率的缺陷,提出测试芳纶标准回潮率的改进方法:采用烘箱法先将纤维试样在烘箱中烘至恒重,然后将烘至恒重的试样在标准大气条件下调湿至平衡状态,最后将调湿平衡的试样在烘箱中烘至恒重,测试芳纶的标准回潮率。结果表明:该方法中起初的预烘干处理消除了芳纶表面的油剂等对测试有干扰的因素,测得的标准回潮率更准确,标准回潮率的相对标准偏差为0.64%,方法的重复性好。     

高强度硅烷化聚氨酯(SPU)密封胶的研究

综述了硅烷化聚氨酯(SPU)密封胶的性能优势和特点,研究硅烷化聚氨酯、填料和黏附促进剂三者对高强度硅烷化聚氨酯密封胶性能的影响。结果表明:中模量的SPUR1、SPUR2树脂和高模量的SPUR3以1∶6的质量比例进行复配使用时,密封胶的强度和断裂伸长率都能满足应用要求;偶联剂A-1100和A-1120进行等量混合使用后,密封胶的固化速率和力学性能都能取得相对较佳效果;在纳米碳酸钙用量占总配方量的50%~60%时,密封胶的补强性及工艺操作性取得最佳平衡。最后介绍了高强度硅烷化聚氨酯密封胶的应用前景。     

高含量哒螨灵原药合成研究

以叔丁基肼水溶液、糠氯酸为原料,在甲苯做溶剂、冰乙酸做催化剂条件下经成腙、闭环、脱溶,然后在水相结晶制得高含量2-叔丁基-4,5-二氯-3(2H)-哒嗪酮(以下简称哒嗪酮);哒嗪酮再与对叔丁基苄硫醇在甲醇做溶剂的条件下经缩合、脱甲醇、水相结晶制得高含量哒螨灵原药。反应具有操作稳定、收率高的优点,缩合反应在低温下进行,有利于提高产品质量及收率;哒螨灵在一定浓度的稀碱水溶液中结晶,其含量可达到96%以上。该方法具有产品质量高、成本低的优点,适合工业化生产。     

Water Content Determinations for Peat and Other Organic Soils Using the Oven-Drying Method

There has been much debate in the literature over the past 60 years regarding an appropriate oven-drying temperature for water content determinations in peat and other organic soils. For inorganic soils, the water content is usually based on the equilibrium dry mass corresponding to drying temperatures in the range 100–110°C. However, for peat and other organic soils, several researchers have recommended lower drying temperatures in the range 60–90°C in an attempt to prevent possible charring, oxidation, and/or vaporization of substances other than pore water. However, all of the relevant water is not fully evaporated at too low a temperature, and because specimen dry mass is a function of drying temperature, the resulting water content values are lower than those determined for the temperature range 100–110°C. Experimental data reported in this article show that oven drying of peat and other organic soils at 100–110°C using either gravity–convection or forced-draft ovens is acceptable for routine water content determinations. Because a standardized oven temperature is desirable when correlating water content with other material properties, it is recommended that oven drying of peat and other organic soils be performed over temperature ranges of either 105–110°C or 105 ± 5°C, in line with standardized ranges for inorganic soils.     

A Moisture Transfer Model for Isothermal Drying of Plant Cellular Materials Based on the Pore Network Approach

Plant materials with cellular structure, like fruits and vegetables, are often viewed as porous media in terms of model building of the drying process, on the basis of a hypothesis that all of the moisture of a plant tissue is trapped in a continuous and connected pore network system. However, most of the moisture in the plant tissue is contained naturally in enclosed cells. In the course of drying, the trapped moisture has to cross the cell membranes and then migrates in the extracellular space. Based on this concept, a pore network model for isothermal drying of plant materials was developed in which two stages of moisture movement—transmembrane transfer and extracellular transfer in the pore network—were considered. Finally, the isothermal convective air-drying processes of a potato slice were simulated. The calculated results were validated by the experiments conducted under the simulation conditions.     

A Generalized Relationship for Determination of Tensile Strength of Fine-Grained Soils from Shrinkage Characteristics

Tensile strength of fine-grained soils has been extensively investigated by earlier researchers and several methodologies have been evolved for its determination. However, either most of these methods are not valid/applicable for a wide range of moisture contents or they involve tedious sample/specimen preparation. In this context, the methodology of determining tensile strength by employing thin films, which is available in the literature, has been found to be quite handy and useful. It has been observed that a unique relationship exists among the tensile strength, moisture content, and shrinkage characteristics of fine-grained soils. This methodology is appreciable due to its applicability to a wide range of moisture contents, comparable ease of sample preparation and testing, and the obtained results lack generalization. Exhaustive tests were conducted on fine-grained soils of entirely different characteristics and generalized relationships have been proposed between the percentage linear shrinkage, tensile strength, and moisture content (defined as liquid to solid ratio). Based on a critical analysis of the results available in the literature, the efficiency of such relationships for determination of tensile strength of fine-grained soils has been demonstrated. In the authors’ opinion, such relationships would be quite useful for determining tensile strength of fine-grained soils from their linear shrinkage, which can easily be measured in a conventional geotechnical engineering laboratory.     

Analysis and Evaluation of Power Formulations for Wood and Hardboard Using Radio Frequency and Microwave Energy

This article analyzes the influence of frequency, temperature, moisture content, and structural orientation on the applicability of the Beer-Lambert law for various wood species using radio frequency and microwave radiation. To achieve this objective, the study compares the power dissipation computed from Maxwell's equation and Lambert's power law. The wood species considered are white oak (Quercus alba), Douglas fir (Pseudotsuga menziesii), trembling aspen (Populus tremuloides), white birch (Betula paperyfera), yellow birch (Betula alleghaniensis), sugar maple (Acer saccharum), and four commercial hardboards. The dielectric constant and dielectric loss factor are examined as a function of moisture conditions, temperature, frequencies, and the three principal structural orientations. The study involved 3,000 complex dielectric constants. It was found that the radial critical thickness is somewhat smaller than the tangential critical thickness (0.95 times smaller) and the longitudinal critical thickness is significantly smaller than the radial (0.52 times). It was demonstrated that the critical thickness L _crit above which the Beer-Lambert law is valid for all of the wood species studied under various conditions obeys the following conditions: log₁₀(L _crt) = 0.999 log₁₀(β^?1) + 0.4122, where β^?1 is the penetration depth (cm). In the case of microwave radiation, the critical thickness can be estimated from L _crt = 2.615 β^?1 ? 0.0626. Finally, a model is proposed to take into consideration the effect of moisture content with frequency (or with attenuation constant).     

第三代煤调湿技术在生产实践中的应用

介绍了第三代煤调湿技术在生产实际应用中对炼焦和煤气净化系统生产带来的不利影响以及在节能方面的效果,同时进行原因分析并提出建议。     

复合可聚合乳化剂制备高固含量低黏度聚丙烯酸酯乳液

以DNS-86和F-6为复合可聚合乳化剂APS为引发剂,MMA、BA为单体采用半连续法制备20%固含量种子乳液,以种子乳液为介质,选用4种不同类型乳化剂:非离子可聚合乳化剂F-6,阴离子可聚合乳化剂DNS-86、常规非离子乳化剂OP-10、常规阴离子乳化剂SDS进行不同组合,同时滴加预乳化液、引发剂、缓冲剂直接二次成核制备62%固含量二元粒径分布乳液。重点研究了乳化剂复合方式、用量及配比、反应温度等对聚合稳定性、乳液流变性等的影响。,