内压圆筒上不同接管型式的有限元分析

文章基于文献[1]的实验,采用三维有限元法对实验中的内压圆筒开孔接管区进行了应力分析,获得了筒体、接管及其连接部位的应力分布结果,并对比分析了径向和周向斜接管结构的应力分布情况。分析结果表明,容器开孔接管处应力分布复杂,并产生明显的应力集中,其应力集中系数随着距接管与筒体连接处的距离的增大而快速降低;周向斜接管结构的应力分布规律与径向接管结构的相类似,最大应力强度均出现在连接处且位于筒体的纵向截面的内侧区域;与径向接管结构相比,周向斜接管结构的最大应力强度较小;而且,随着周向斜接管结构的倾斜角α增大,其最大应力值变小。     

胶乳改性乳化沥青性能试验研究

实验室内通过添加不能掺量的SBS胶乳和SBR胶乳分别制成改性乳化沥青。分别考察了筛上剩余量、恩格拉粘度、储存稳定性以及残留物的软化点、延度等几项主要指标随胶乳掺量变化的情况。SBS胶乳和SBR胶乳在对乳化沥青高低温性能的改善上各有侧重,建议在对高温性能要求较为严苛的地区使用SBS胶乳改性乳化沥青,而在对低温性能要求较为严苛的地区使用SBR胶乳改性乳化沥青。     

Kriging插值中条件数据点个数的选择

Kriging插值时使用的数据量越大,插值结果越可靠,但数据量对耗时的影响则呈指数增加。为了保证尽量多的数据参与Kriging插值,又能维持合理的计算耗时,必须正确地选择条件数据点个数。通过对地质统计学中Kriging插值算法的深入解析,利用Kriging插值中产生的平均权系数分析插值过程中的条件数据点个数的选择,当平均权系数最小时,找到这个平衡点,让插值过程中的计算在保证计算精度的同时,尽量减少计算耗时。并改变Kriging插值的维数、网格大小和变差函数的变程,分析所选择的条件数据点个数对此3种因素的敏感度,得到条件数据点个数选择40～60最为合适,主要的影响因素为计算维数。     

普光气田层序地层格架与储层发育特征

综合利用露头、岩心、测井和地震资料,对川东断褶带普光气田飞仙关组、长兴组储层进行了高频层序分析、沉积相预测和有利储集带预测。将长兴组划分为2个三级层序、6个四级层序和10个五级层序;飞仙关组划分为2个三级层序、8个四级层序和19个五级层序。在三级层序的层面上,论述了层序特征,进行了沉积相预测;该区储集空间主要为溶蚀孔隙,储层发育具有明显相控性,高能环境下的颗粒灰岩经白云化形成的孔隙远高于低能环境下地层的孔隙;鲕滩和生物礁基本上都经历了较好的暴露和溶蚀,一般孔隙发育较好;斜坡、陆棚、泻湖及潮坪多发育高放射性的泥岩,孔隙不发育。     

The improving effect of spray-drying encapsulation process on the bitter taste and stability of whey protein hydrolysate

Although whey protein hydrolysate (WPH) possesses good physiological functionality, its bitter taste and hygroscopic property limit its direct utilization as food ingredient. The aim of this work was to encapsulate whey protein hydrolysate by spray drying using maltodextrin or maltodextrin/??-cyclodextrin mixture as wall materials to attenuate the bitter taste and enhance the stability of whey protein hydrolysate. Hygroscopicity, glass transition temperature, bitter taste, and morphology of non-encapsulated WPH and encapsulated WPH were evaluated. Solubility, particle size, bulk density, and moisture content were also measured. Compared with the non-encapsulated WPH, the encapsulated WPH exhibited significantly lower hygroscopicity and higher glass transition temperature. The bitterness of both maltodextrin-encapsulated WPH and maltodextrin/??-cyclodextrin-encapsulated WPH was significantly lower than that of the original non-encapsulated WPH. Morphological analysis by scanning electron microscopy showed that the microcapsules of the spray-dried encapsulated WPH were matrix-type with less link bridge and had a continuous wall with many concavities. In addition, encapsulation process did not exert negative effect on the solubility of whey protein hydrolysate. The results indicated that encapsulation with maltodextrin and ??-cyclodextrin as carriers was helpful to attenuate the bitter taste and enhance the stability of whey protein hydrolysate.     

Fabrication of Reduced Fat Products by Controlled Heteroaggregation of Oppositely Charged Lipid Droplets

Abstract: This study describes how the rheological properties of colloidal dispersions formed by heteroaggregation of oppositely charged protein‐coated lipid droplets depend on total particle concentration. Mixed‐particle emulsions were formed by mixing single‐particle emulsions containing either β‐lactoglobulin‐coated lipid droplets (ζ≈?42 mV, d₄₃≈ 0.35 μm) or lactoferrin (LF)‐coated lipid droplets (ζ≈+26 mV, d₄₃≈ 0.32 μm). A series of single‐particle and mixed‐particle emulsions with different total fat contents (5% to 40%) were prepared, and their mean particle size, apparent viscosity, and shear modulus were measured. Mixed‐particle emulsions (40% LF: 60%β‐Lg) containing relatively high fat contents (>10%) had high viscosities and paste‐like properties. These rheological characteristics were attributed to extensive particle aggregation and network formation due to electrostatic attraction between oppositely charged droplets. The viscosities of mixed‐particle emulsions were much higher than those of single‐particle emulsions with equivalent fat contents. Measurements of the color coordinates (L*, a*, b*) of mixed‐particle emulsions with low fat contents showed that they had similar appearances as single‐particle emulsions with high fat contents. This study has important implications for the creation of reduced fat foods with similar sensory qualities as higher fat foods. Practical Application: This study describes how novel food materials can be created by mixing together negatively charged and positively charged lipid droplets. These mixed emulsions may be suitable for the creation of reduced fat products, since they have high viscosities and paste‐like properties at relatively low fat contents.     

微小机械的研究现状和动向

介绍了微小机械的发展现状及国外在这方面的最新研究成果,对微小机械的研究方向提出了见解。     

顶空气相色谱法同时测定铀产品中痕量氯,溴,碘

本工作研究了一种灵敏简便的同时测定氯、溴,碘的顶空气相色谱法,并成功地应用于铀产品中氯、溴、碘的分析。 方法基于氯、溴、碘在中性或酸性介质中与硫酸二甲酯反应,生成氯甲烷、溴甲烷、碘甲烷;应用顶空气相色谱法,不需经分离手续,即可同时测量这些卤代甲烷,在样品分析时用标准加入法定量。本方法较液体进样的气相色谱法提高灵敏度1至2个数量级,可以用于测定铀产品中ppm数量级的氯,ppb数量级的溴和碘。三个元素的回收率均大于90％。     

钩编机在家纺花边生产中的应用

钩编花边按其外观形态可分为花边带、缨边花边、毛边花边和底摆花边，文中分别阐述了编织这些花边的设备要求和技术要求，并结合实例具体说明了它们的编织工艺。     

汽车用液化石油气加气站的设计技术

介绍了车用液化石油气加气站的形式、主体设施(包括用作液化气槽车卸车、卧罐储存、汽车加气和安全消防的设施)和加气站的设备选择及配备,以及加气站的总平面设计、工艺安装及电气、仪表控制设计中应注意的问题。