Solvent fractionation of hard palm stearin to increase the concentration of tripalmitoylglycerol and dipalmitoyl-stearoyl-glycerol as substrates for synthesis of human milk fat substitute

This research aimed to produce triacylglycerols fraction rich in palmitic acid (PA) at the sn-2 position from hard palm stearin (HPS) through acetone fractionation. Fractionations were done at HPS-to-acetone ratios of 1:3, 1:5 and 1:7 (w/v) and at temperatures of 25, 30 and 35 °C for 3 h. Triacylglycerols with PA at the sn-2 position, such as tripalmitoylglycerol (PPP) and dipalmitoyl-stearoyl-glycerol (PPS), were concentrated in the solid fraction, obtained after separation by filtration. The optimal fractionation conditions were at a HPS-to-acetone ratio of 1:5 (w/v) and 30 °C. The total PPP and PPS content was more than 91%, with a corresponding yield of more than 59%. Triacylglycerols obtained were composed of more than 91% PA in which 88% were at the sn-2 position. Conclusively, the solvent fractionation is a suited alternative method for the preparation of triacylglycerols used for the enzymatic synthesis of 1,3-dioleoyl-2-palmitoylglycerol which is the main triacylglycerol for human milk fat substitute.     

多晶硅锭中硬质点分析及控制研究

以多晶硅锭中硬质点为研究对象,通过实验研究和数值模拟的方法,对多晶硅锭中硬质点进行形貌和成分分析,并提出改善控制方法。研究结果表明硅锭中部的硬质点较细小,主要由SiC组成;硅锭头部的硬质点较粗大,主要由SiC和Si3N4组成,还有少量O的存在。进一步研究发现多晶硅定向凝固铸锭炉的热场结构对于多晶硅锭硬质点形成有直接影响,通过改进热场结构,优化晶体生长界面,显著减少了铸锭中硬质点的数量。     

MG410采煤机滚筒辅助叶片板的增设与应用

针对MG170/410-WD滚筒式采煤机在大倾角、仰角、“三软”煤层使用中遗漏在机道中的浮煤多、装煤效率低等问题,通过添加螺旋板数量对采煤机滚筒进行改造。改造后,在滚筒转速不变的情况下,提高抛煤效率,缩短了工作面割煤和工作面空顶时间,提高了装煤效率,从源头上降低了顶板管理的安全风险。     

煤层顶板裂隙高位定向长钻孔安全高效抽采技术的研究与应用

放顶煤开采期间，上覆岩层受到矿压的影响，形成冒落带、裂隙带、弯曲下沉带，工作面采空区遗煤和围岩涌出的大量瓦斯飘浮在上方裂隙带区域，造成瓦斯聚集并向外涌出，形成了安全隐患，因此必须将该区域瓦斯抽出来；以往治理采空区瓦斯主要采用顶板裂隙高位钻场、顶板高抽巷等措施，但是这2种方法施工成本较高，且施工周期长，对生产接替影响较大。煤层顶板裂隙高位定向长钻孔安全高效抽采采用大功率钻机+定向钻进技术，在裂隙带施工控制整个回采范围的长钻孔，减少采空区和邻近层瓦斯向工作面空间的流动，真正实现了“以孔代巷”，既节省了成本，又缩短了工期，还提高了采空区瓦斯抽采的连续性、稳定性，减少了采空区瓦斯向外涌出，提升了瓦斯抽采效果，促进了煤矿安全高效发展。     

综放工作面防治水技术应用实践

为解决21000工作面采空区及顶板涌水问题,根据工作面出水点的不同情况,采取了集水器导水、老塘设挡水堰截水、挖排水沟疏水等多项治水措施,经统计排水量达33~42m3/h,有效控制了水情,确保了工作面正常生产。     

碎软煤层条带瓦斯地面高效抽采技术研究

为了提高碎软煤层条带瓦斯抽采效率和效果,基于目前地面瓦斯抽采主要采用垂直井或从式井的方式抽采效果差、效率低的现状,通过理论和实验分析论证了穿岩层压裂改造煤储层的可行性,提出了在目标煤层顶板岩层中钻水平井,并通过垂直向下射孔以及采用泵送桥塞分段进行压裂的方式进行地面瓦斯抽采。试验结果表明:顶板分段压裂水平井单井产量高、高稳产期更长、产量衰减更慢;有效水平井段控制区域内瓦斯下降均匀,更有利于进行条带瓦斯抽采;相同投资条件下,采用水平井的方式瓦斯抽采效率和投入产出比更高。     

油基钻井液的封堵性能研究与应用

在涠洲12-1北油田一期工程中使用油基钻井液后事故率明显降低,但仍未能彻底解决涠二段硬脆性泥页岩井壁稳定性问题。对进一步加强油基钻井液的封堵能力进行了室内研究。通过在油基钻井液中引入超微细颗粒材料、纤维材料、变形材料和粘弹性材料,可大幅度提高其封堵能力。在涠洲12-1北油田二期工程中应用了加强封堵能力的油基钻井液,结果钻井施工非常顺利,几乎无井下复杂事故。室内评价及二期工程实践结果表明,增强油基钻井液的封堵能力对保持硬脆性泥页岩井壁稳定至关重要。     

控制爆破切槽放顶处理空区技术探讨

文中筒要讨论了国内外黄金矿山采空区处理的几种方法。在对金风公司采空区综合评价与应力测试基础上．提出了控制爆破切槽放顶处理采空区的新技术，并详细介绍了新技术要点及实施细节。应用实践表明，该技术简便易行、经济安全、具有创新性。     

强捻棉纱针织产品的性能研究

通过对强捻棉纱针织产品进行服用性能测试，得出强捻纱织物具有良好的服用性能。     

Attribute Allocation and Retrieval Scheme for Large-Scale Sensor Networks

Wireless sensor network is an emerging technology that enables remote monitoring of large geographical regions. In this paper, we address the problem of distributing attributes over such a large-scale sensor network so that the cost of data retrieval is minimized. The proposed scheme is a data-centric storage scheme where the attributes are distributed over the network depending on the correlations between them. The problem addressed here is similar to the Allocation Problem of distributed databases. In this paper, we have defined the Allocation Problem in the context of sensor networks and have proposed a scheme for finding a good distribution of attributes to the sensor network. We also propose an architecture for query processing given such a distribution of attributes. We analytically determine the conditions under which the proposed architecture is beneficial and present simulation results to demonstrate the same. To the best of our knowledge, this is the first attempt to determine an allocation of attributes over a sensor network based on the correlations between attributes.