Subjects: Materials Science >> Materials Science (General) submitted time 2023-03-18 Cooperative journals: 《材料研究学报》
Abstract： Due to the complicated geometry and thin wall of the stainless steel impeller, during the investment casting process, some casting defects such as shrinkage porosity and filling shortage are usually produced, which have a close relationship with the filling and solidification process. So, the software ProCast was used to study the filling and solidification process of impeller and the numerical simulation results were compared with the experimental results in this paper. The following results can be acquired: 1. when the pouring temperature is 1550℃ and the casting speed is 0.75 m/s, the investment casting impeller can be filled to avoid the filling shortage defect; 2. although the appropriate pouring temperature and casting speed can avoid the filling shortage defect, but it can not avoid the shrinkage porosity defects in the impeller casting; 3. to pre-place certain cold iron in the middle of the impeller casting mold according to its structural characteristics can eliminate the shrinkage porosity defects. When the height of the pre-placed cold iron is 1/3 of the height of the inner cavity of impeller mold, the effectiveness in elimination the defects in the castings is the best thereby a high quality impeller can be acquired.
Subjects: Biology >> Botany >> Applied botany submitted time 2021-04-29 Cooperative journals: 《广西植物》
Abstract： Ardisia gigantifolia Stapf. is a common Chinese medicinal material in Southwest China, which is widely used in food stewing and medicinal bath. In recent years, the leaves of A. gigantifolia have been developed to make tea, which has effectively broadened the way of application. In order to clarify the nutritional value of A. gigantifolia leaves, we used the national standard method to analyze and evaluate the mineral elements, general nutrients, amino acids and active components of its leaves in different cultivation years, so as to provide scientific basis for its development and utilization. The results were as follows: (1) The leaves of A. gigantifolia contained rich mineral nutrition, which has the characteristics of high potassium and low sodium food. The contents of P, K, Cu, Fe, Mn and Zn in leaves of 1-year-old plants were significantly higher than those of 2-4-year-old plants (P < 0.05). (2) The contents of general nutrients and amino acids of A. gigantifolia leaves were higher. The contents of vitamin C, total sugar and amino acid in leaves of 4-year-old plants were significantly higher than those of 1～3 years old plants (P < 0.05). (3) The leaves of A. gigantifolia were rich in phenols and saponins, but the content of flavonoids was low. The content of total saponins in 1-year-old and total phenolsin 4-year-old were significantly higher than that in other cultivated years (P < 0.05). The mineral nutrition and saponins were the most abundant in 1-year-old, and general nutrition, amino acids andphenols were the most abundant in 4-year-old of A. gigantifolia plants. Compared with common fruits, vegetables and tea, leaves of A. gigantifolia have higher nutritional value and better development and utilization prospects.
Subjects: Medicine, Pharmacy >> Clinical Medicine submitted time 2018-12-04 Cooperative journals: 《协和医学杂志》
Abstract：目的探讨加速康复外科胃癌患者术后不常规留置导尿管的可行性。方法回顾性分析2016年6月至2017年3月，南京总医院普通外科采用加速康复外科理念择期行胃癌根治术患者的临床资料。人选患者麻醉诱导期插人导尿管，手术结束时即刻拔除导尿管并以此时间为观察起始点，记录患者术后首次排尿时间、首次排尿量、重插尿管的比例，分析首次排尿延迟及重插尿管的危险因素。结果137例患者纳人本研究，其中男90例(65.7%)，女47例(34.3 %) ,平均年龄X58.9士10. 1)岁，术后首次排尿时间为(}5. 3士2. 1) h，首次自解尿量(298. 9101. 3 ) ml，重置尿管比例为11.7% (16/137);相比开腹组，机器人组自主排尿率高，诱导排尿率、重置导尿管及尿路刺激征发生率均较低(P均6 h组术中输液量较多、术中尿量较多、首次自解小便时间及首次下床活动时间均延迟(P均<0.01)。结论加速康复外科胃癌患者术后即刻拔除尿管是可行的，术中控制性输液、多模式镇痛是不常规留置导尿管的基础条件，机器人手术有利于患者术后早期恢复自主排尿
Subjects: Biology >> Bioengineering submitted time 2018-05-16 Cooperative journals: 《中国生物工程杂志》
Abstract：细胞穿膜肽（Cell-penetrating peptide,CPP）作为一种体内大分子药物跨膜运输载体被广泛研究和应用。中期因子Midkine（MK）是人体的一种带有肝素结合域（Heparin-Binding Domain，HBD）的生长因子。本文报道了MK中HBD的部分富含碱性氨基酸的基因序列（命名为MK-S0）与绿色荧光蛋白（EGFP）基因融合表达后，能将EGFP有效地转运入胞内，且其穿膜转运效率高于经典穿膜肽Tat。将MK-S0序列进行进一步突变优化改造得到的MK-∆4，其穿膜效率比天然序列来源的MK-S0提高16倍以上，且MK-∆4的穿膜转运作用适用于多种肿瘤细胞。穿膜机理分析研究结果显示，MK-∆4可与细胞表面硫酸乙酰肝素结合，随之以巨胞饮形式内吞入胞。采用MTT方法检测的细胞生长抑制试验结果显示，连接有MK-∆4的苦瓜来源的核糖体失活蛋白MAP30比单独的MAP30对HeLa肿瘤细胞的IC50值降低5.8倍，大大提高了这种药物蛋白抑杀肿瘤细胞的效果。由此表明，源于MK的这种经过突变改造的MK-∆4，可作为一种新型高效的细胞穿膜肽，将药物蛋白有效运输到细胞内发挥抗肿瘤效应。
Subjects: Library Science，Information Science >> Information Science submitted time 2017-11-08 Cooperative journals: 《数据分析与知识发现》
Abstract：【目的】为满足电网公司针对新能源项目投资进行管控的需要, 尝试基于电网公司内部大数据, 建立面向新能源项目投资效益评价的数据抽取方法和评价指标体系。【方法】基于电网公司SG-ERP 系统架构, 构建面向大数据应用的数据管理体系, 提出基于Golden Gate 的评价数据抽取方法, 建立覆盖项目经济、社会、环境效益,及项目决策期、建设期和运营期的全过程评价指标体系, 并辅以Delphi 法进行验证。【结果】通过实证得到指标变异系数权重和Y 市电网公司2015 年新能源项目投资的经济、社会和环境效益得分。【局限】量化评价指标时采取的分类标准可进一步细化。【结论】本研究方案可实现电力新能源项目投资效益全过程的评价, 数据抽取方法、评价指标体系和权重算法具有一定的推广价值。
Subjects: Materials Science >> Materials Science (General) submitted time 2017-03-31 Cooperative journals: 《腐蚀科学与防护技术》
Abstract：针对海南省内变电站接地网土壤腐蚀问题，对海南境内17个地区，共计33所变电站（11座35kV变电站，17座110kV变电站和5座220kV变电站）进行调研，对变电站接地网实际腐蚀程度进行了分类。同时对海南省各变电站接地网所处土壤环境的腐蚀等级进行评价，结果显示，33所变电站内土壤腐蚀等级为C2~C5级，其中处于C2级的仅8个，占24.2%，属轻度腐蚀；处于C3级的15个，占全部的45.5%，属中等腐蚀；处于C4、C5级的10个，占全部的30.3%，为严重腐蚀、重度腐蚀；对海南省各变电站内直流杂散电流强弱程度进行测量，均处于中、高级。分析了接地网土壤腐蚀的原因。
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