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41.
通过蒸汽辅助重力泄油(Steam Assisted Gravity Drainage,SAGD)技术开采稠油时,采出液温度较高,对其进行热回收的节能潜力较高,油田采用热管式换热器回收采出原油的余热,将其作为工业或生活用热具有研究价值。考虑到现场空间要求和工程设备模块化的特点,利用U形管壳式换热器、螺旋板式换热器作为分离型热虹吸热管蒸发段和冷凝段,并建立复合式分离型热管模型,分析其换热性能、循环压降、充液率及换热能力。采用新疆油田油水二次换热区的分离型热管系统验证该模型,结果表明:复合式分离型热管计算模型可行;复合式热管具备U形管壳式换热器、螺旋板式换热器的优点,换热性能强,系统换热能力可以满足实际要求,有较好的环境适应性。 相似文献
42.
对最新版本的《南京市绿地系统规划》(2013-2020)进行分析与研究,综合相关规划文件,对南京市近几年绿地规划、建设内容进行回顾与评价,总结南京市在绿地规划方面的可取与不足之处。对南京城市的历史沿革、山水格局、绿地现状、自身定位、发展趋势进行思考,结合国内政策、国外理念等因素统筹地对南京未来的绿地发展方向进行展望与研究,包括绿地宏观布局层面、中观联系层面、微观建设层面3方面。 相似文献
43.
Chengquan Tan Yongcheng Ji Xichen Zhao Zhongquan Xin Jiaying Li Shuangbo Huang Zhiying Cui Lijun Wen Caihua Liu Sung Woo Kim Jinping Deng Yulong Yin 《动物营养(英文)》2021,7(1):111
Increased metabolic burdens in breeding sows, which are induced by elevated systemic oxidative stress, could increase the need for nucleotides to repair lymphocyte DNA damage; however, de novo synthesis of nucleotides may be insufficient to cover this increased need. This study investigated the effects of dietary nucleotides on milk composition, oxidative stress status, and the reproductive and lactational performance of sows. Forty multiparous sows were assigned to 2 dietary treatments (Control group, and 1 g/kg Nucleotides group) based on a randomized complete block design using their BW at 85 d of gestation as a block. Sows from 2 groups were fed a restricted diet during gestation and ad libitum during lactation. The experiment lasted from 85 d of gestation to 21 d of lactation. The reproductive performance of sows and the growth performance of suckling piglets were measured. Oxidative stress parameters and milk components were also analysed. Data were analyzed using contrasts in the MIXED procedure of SAS. Sows in the Nucleotides group consumed more feed during the first week (P < 0.01) and from 1 to 21 d (P < 0.05) of lactation than those in Control group. Correspondingly, the litter weight gain of piglets showed a tendency to increase from cross-fostering to 9 d (P = 0.09) and from cross-fostering to 20 d (P = 0.10) in the Nucleotides group relative to the Control group. Additionally, the Nucleotides group was higher (P < 0.01) than the Control group in the concentrations of uridine 5''monophosphate, guanosine 5''monophosphate, inosine 5''monophosphate, adenosine 5''monophosphate and total nucleotides in milk. Furthermore, the Nucleotides group was higher (P < 0.01) than the Control group in the serum levels of total antioxidant capacity (P < 0.01) for sows at 109 d of gestation and glutathione peroxidase for weaning piglets, but lower at the levels of thiobarbituric acid-reactive substances (P < 0.05) in serum of weaning piglets. This study indicated that maternal dietary nucleotides could promote piglet growth, probably due to the higher lactational feed intake and higher concentration of nucleotides in the milk of sows, and lower oxidative stress for both sows and piglets. 相似文献
44.
在喷灌工程规划设计过程中,正确地选用规划设计方案,实际是一个综合分析决策的过程。主要应考虑的因素中,有些可定量,有些则是无法定量的。如何对非定量因素作定量分析,进而对整个喷灌规划设计方案作出评价决策,层次分析法是解决这类问题简洁、有效、实用的方法。 相似文献
45.
本文介绍一种用于分离检测土壤中棉枯萎病菌的选择性培养基—植选2号。其成分为:KH_2PO_41g,MgSO_4·7H_2O 0.5g,K_2S_2O_50.2g,KCl0.6g,NH_4NO_3 0.5g,蛋白胨5g,山梨糖10g,蔗糖5g,琼脂20g,蒸馏水1000ml,PCNB 620mg,Oxgall1g,硫酸链霉素300mg,盐酸金霉素75mg。根据棉枯萎病在此培养基上的形态特征,能较容易地识别和检测该病菌。 相似文献
46.
详述了首次在国内午餐肉罐头生产中采用的微波解冻系统科技成果的实施情况、系统操作与安全控制特点以及运行条件。探讨微波解冻技术支持下,无亚硝酸钠午餐肉罐头的生产工艺原理及其品质卓越的原因。 相似文献
47.
The green is as a symbol of no pollution,no public harm and environmental protection. The green automobile is the inevitable results that the automobile technique continuously developes. A new style vehicle--the green automobile is the urgent solicit of environmental protection is developed. The automobile industry can develop continuously. This article mainly discusses the importance of the green auto_mobile's research and development,the development status in quo and prospect of the green auto_mobile technique in the world,and states the relationship between the green automobile technique and environmental protection from green technical system theoretically clarify the study of green automobile,including its design and the system,the manufacture and its technology,the energy,the rebuild engineering and a series of subjects. How to evaluate the cycle and the evaluable mark of the green automobile,the prospect of green automobile are pointed out. 相似文献
48.
In TT&C system,unified spread spectrum framework and adaptive antenna digital beamforming technologies are used to track, telemetry and command objects. Constant modulus array (CMA) and adaptive signal canceller estimate the direction of arrival (DOA) of every signal and use the optimum weighted vector to form the beams. The phase weighted vectors estimated from DOA improve the processing gain as well as being utilized in the transmitting of tele command signal to form the beam of specified object. Its processing performance is researched and simulated in this paper. 相似文献
49.
The design of Bio-clean operating room in modern hospital is quite different from that of traditional operating room. This paper discusses three aspects of Bio-clean operating room design: air clean standard and air purification, interior equipment system and interior finish. It is hoped that this discussion will conduce to later designs. 相似文献
50.
Modeler and simulation modules in Ideas software are used to build the finite element models on involute gear and double involute gear with accurate tooth shape, and with the same design parameters and under the same loads, finite element contact analysis has been done. At last, the contact stress and bending stress on the two types gear transmission at the different meshing positions are solved out, and comparative analysis and study have been done. At the same time, that the ladder-shape tooth on the double involute gear how to influence contact stress and bending stress is emphatically analysed. All above offer the theoretical foundation that bring the double involute gear with ladder-shape tooth into the industry. 相似文献