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深水多相混输管输量调整对乙二醇管理影响 被引量:1
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作者 王飞 王梓力 +1 位作者 李文昭 王凯 《天然气技术与经济》 2018年第3期37-40,共4页
为了提高乙二醇管理水平和确保管道运行的安全,以目前具有代表性的荔湾3-1气田为例,利用成熟的OLGA商用软件,模拟研究分析了管输量改变对乙二醇贫液加注及富液再生的影响,分析获得了以下结论:(1)在减输过程中,管道积液量增大,为达到新... 为了提高乙二醇管理水平和确保管道运行的安全,以目前具有代表性的荔湾3-1气田为例,利用成熟的OLGA商用软件,模拟研究分析了管输量改变对乙二醇贫液加注及富液再生的影响,分析获得了以下结论:(1)在减输过程中,管道积液量增大,为达到新的平衡需增加乙二醇贫液的储存量;(2)在增输过程中,大量积液被顶出管道,对平台液相分离能力提出了更高的要求,应增强乙二醇富液的储存和处理能力。并建议随着输量调整幅度增大,宜采取多阶段递阶式缓解液涌的调整策略,达到新平衡态所需时间延长。 展开更多
关键词 深水气田 多相流管道 管输量调整 动态模拟 乙二醇管理
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天然气管输成本测算与合理收费方法探讨 被引量:2
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作者 张孝松 《天然气技术与经济》 2003年第1期38-41,78,共5页
天然气管输收费以管输成本为基础,这是目前公认的作法。本文从分析天然气管输成本的影响因素入手,推导出在一定管道条件下,管输成本与运距、输气量的关系,从而给出了天然气管输成本测算公式,说明了管输成本的构成与形成规律,证明了我国... 天然气管输收费以管输成本为基础,这是目前公认的作法。本文从分析天然气管输成本的影响因素入手,推导出在一定管道条件下,管输成本与运距、输气量的关系,从而给出了天然气管输成本测算公式,说明了管输成本的构成与形成规律,证明了我国制定的按管榆运距收费的办法有一定根据,同时指出其缺陷和不足,并提出了按管输成本构成特点和国际通行的两部制收费办法的建议。 展开更多
关键词 管输成本 管输量 管输运距 管输费构成
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管道独立改革有效性的博弈分析
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作者 丁鹏 李宏勋 《甘肃科学学报》 2015年第5期117-121,共5页
通过建立双寡头油气企业管输量的Hotelling模型分析管道独立改革在促进油气价格市场化和解决管道重复建设问题中的作用,得出四点结论:油气企业总是存在自建管道的动机;油气企业对独立管道公司的依赖程度越高,油气企业的利润越低;高成本... 通过建立双寡头油气企业管输量的Hotelling模型分析管道独立改革在促进油气价格市场化和解决管道重复建设问题中的作用,得出四点结论:油气企业总是存在自建管道的动机;油气企业对独立管道公司的依赖程度越高,油气企业的利润越低;高成本油气企业可以通过管输量优势降低甚至扭转其在市场竞争中的劣势;独立管道公司有过度提高单位油气运输价格的动机。并提出四点政策建议:为保证改革的有效性,政府需要禁止油气企业自建管道;协调独立管道公司和油气企业之间管输利润的分配关系;采取措施防止出现竞争失衡状况,始终使油气市场保持充分的竞争性;对管道公司管输定价进行监管,防止其利用市场势力损害消费者利益。 展开更多
关键词 HOTELLING模型 独立管道公司 管输量 管道重复建设
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Energy Balance in Crop Production 被引量:1
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《Journal of Agricultural Science and Technology(B)》 2012年第5期527-533,共7页
The most appropriate method of energy balancing in crop production is the process analysis where fossil energy input is considered rather than manpower or solar energy. In our approach, fossil energy input is split to... The most appropriate method of energy balancing in crop production is the process analysis where fossil energy input is considered rather than manpower or solar energy. In our approach, fossil energy input is split to direct and indirect input components. Direct energy input includes the consumption of diesel fuel required for field operations taking into account the influences of location and management conditions. Moreover, energy consumption for construction of agricultural machines is also considered as direct energy input. Indirect energy inputs include seed material, plant protection agents, fertilizers and operation of machines. Production and utilisation of nitrogen (N) fertilizer represents by 50% of energy consumption in agricultural systems. Data from a field experiment conducted during 1995-2000 on a fertile sandy loess in the Hercynian dry region of central Germany were used to determine the energy efficiency of winter oilseed rape (Brassica napus L.) as affected by nitrogen (N) fertilization. Our results show that different N management strategies affect the energy balance of the seed oil. Lowest energy input and energy output occurred in the unfertilized crop. The energy efficiency was determined using the parameters energy gain (net energy output), energy intensity (energy input per unit grain equivalent GE; term GE is used to express the contribution that crops make to the nutrition of monogastric beings), and output/input ratio. The most favourable N rate for minimum energy intensity was 80 kg N hal while that needed for maximum energy gain was 160 kg ha1. Output/input ratio was the highest at 80 kg N ha-l. 展开更多
关键词 Energy balance nitrogen fertilizer crop production.
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Effects of Saline Administration, Abdominal Compression, and Prolongation of Acquisition Delay on Image Quality Improvement of CT Urography 被引量:7
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作者 Hao Sun Hua-dan Xue +3 位作者 Wei Liu Xuan Wang Yu Chen Zheng-yu Jin 《Chinese Medical Sciences Journal》 CAS CSCD 2012年第4期201-206,共6页
Objective To retrospectively evaluate the effects of saline administration following contrast material injection, abdominal compression and two delay phase acquisition on image quality improvement of computed tomograp... Objective To retrospectively evaluate the effects of saline administration following contrast material injection, abdominal compression and two delay phase acquisition on image quality improvement of computed tomographic urography (CTU). Methods Medical records and informed consents of patients were obtained. In totally 122 patients (50 men, 72 women), two delay phase images with CTU were performed. Scans began simultaneously with a contrast bolus injection of 100 mL (300 mgI/mL) followed by a saline bolus injection of 100 mL at a rate of 5 mL/s. Two delay phase images were taken at 400 and 550 seconds for each patient. Examinations were taken by using abdominal compression or not. The distention and opacification of the urinary tract were evaluated by two interpreters together on transverse images and post-processing images. Effects of four techniques (saline administration and abdominal compression, saline administration only, compression only, and neither saline administration nor compression) and two delay phase acquisition on image quality improvement were analysed by using ANOVA and Chi-square test. Results Saline administration improved opacification (P<0.05) and increased overall image quality (P<0.01) of the intrarenal collecting system and proximal ureter. Abdominal compression (P<0.05) and delayed phase image acquisition of 550 seconds (P<0.01) all improved distention of the intrarenal collecting system and proximal ureter but did not improve opacification. No statistically significant effects on the distal ureter were found. However, there were more visualized distal ureteral segments with the longer imaging delay. Conclusion Saline administration, abdominal compression and longer imaging delays are all effective in improving image quality of 64-detector row CTU. 展开更多
关键词 computed tomographic urography image quality
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Hepatorenal syndrome 被引量:4
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作者 Jan Lata 《World Journal of Gastroenterology》 SCIE CAS CSCD 2012年第36期4978-4984,共7页
Hepatorenal syndrome(HRS) is defined as a functional renal failure in patients with liver disease with portal hypertension and it constitutes the climax of systemic circulatory changes associated with portal hypertens... Hepatorenal syndrome(HRS) is defined as a functional renal failure in patients with liver disease with portal hypertension and it constitutes the climax of systemic circulatory changes associated with portal hypertension.This term refers to a precisely specified syndrome featuring in particular morphologically intact kidneys,where regulatory mechanisms have minimised glomerular filtration and maximised tubular resorption and urine concentration,which ultimately results in uraemia.The syndrome occurs almost exclusively in patients with ascites.Type 1 HRS develops as a consequence of a severe reduction of effective circulating volume due to both an extreme splanchnic arterial vasodilatation and a reduction of cardiac output.Type 2 HRS is characterised by a stable or slowly progressive renal failure so that its main clinical consequence is not acute renal failure,but refractory ascites,and its impact on prognosis is less negative.Liver transplantation is the most appropriate therapeutic method,nevertheless,only a few patients can receive it.The most suitable "bridge treatments" or treatment for patients ineligible for a liver transplant include terlipressin plus albumin.Terlipressin is at an initial dose of 0.5-1 mg every 4 h by intravenous bolus to 3 mg every 4 h in cases when there is no response.Renal function recovery can be achieved in less than 50% of patients and a considerable decrease in renal function may reoccur even in patients who have been responding to therapy over the short term.Transjugular intrahepatic portosystemic shunt plays only a marginal role in the treatment of HRS. 展开更多
关键词 Liver cirrhosis Hepatorenal syndrome As-cites VASOCONSTRICTORS Terlipressin
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A statistical hiding algorithm based on self-similar network traffic
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作者 沙学军 徐玉滨 强蔚 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2008年第1期100-103,共4页
Although the encryption of network packets significantly increases privacy, the density of the traffic can still provide useful information to the observer, and maybe results in the breach of confidentiality. In this ... Although the encryption of network packets significantly increases privacy, the density of the traffic can still provide useful information to the observer, and maybe results in the breach of confidentiality. In this paper, we address issues related to hiding information in self-similar network, which is proved to be similar with modern communication network. And a statistical hiding algorithm is proposed for traffic padding. The figures and the comparison of Hurst Parameters before and after traffic padding, show the effective performance of the algorithm. 展开更多
关键词 Self-similar traffic Hurst Parameter FGN hiding algorithm traffic padding
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Transumbilical laparoendoscopic single-site surgery of simple nephrectomy of nonfunctioning kidney: a two-year experience 被引量:1
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作者 Wang Linhui Wu Zhenjie Liu Bing Yang Qing Chen Wei Sheng Haibo Xu Zunli Wang Cheng Sun Yinghao 《Journal of Medical Colleges of PLA(China)》 CAS 2011年第4期213-221,共9页
Background: Laparoendoscopic single-site surgery (LESS) may serve as a potential alternative to conventional laparoscopy and is developing quickly, but still in its infancy. The study is to present our two-year exp... Background: Laparoendoscopic single-site surgery (LESS) may serve as a potential alternative to conventional laparoscopy and is developing quickly, but still in its infancy. The study is to present our two-year experience in transumbilical LESS simple nephrectomy (LESS-SN) for non-functioning kidney, in an effort to evaluate its feasibility, clinical outcomes and potential advantages. Methods: From December 2008 to December 2010, a total of 11 patients with body mass index (BMI)≤30 underwent transumbilical TriPortTM LESS-SN by a single experienced urologist at our institution. The indications for nephrectomy included nonfunctioning kidney associated with ureteropelvic junction stricture (n=l), ureteral calculi (n=6), tuberculosis (n=3), and ureteral stricture (n=l). Patient demographics perioperative and follow-up data were prospectively collected and analyzed. Results: Ten procedures were successfully completed with one patient converted to open surgery due to uncontrollable bleeding. The mean operative time was 189.2 (ranging 100-320 min) with an estimated blood loss of 204.5 (ranging 50-1 000 ml). There were two complications of bleeding (1- intra-, 1- post-). The mean hospitalization after surgery was 7.9 d (ranging 4-17 d) With a regular follow-up of 1, 6, 12, and 24 months after surgery, all patients remained symptom-free with an intra-umbilical scar. Conclusion: Transumbilical LESS simple nephrectomy for nonfunctioning kidney can be accomplished with favorable surgical outcomes and a superiority of cosmesis. However, cases with chronic inflammation are not suitable for initial up-take and should only be attempted by the very experienced laparoscopist. 展开更多
关键词 Laparoendoscopic Single-site Surgery Laparoendoscopic single-site surgery LAPAROSCOPY NEPHRECTOMY
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Improvement of Physical and Biological Quality of Soil in a Sugarcane Plantation through the Management of Organic Matter Input
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作者 Nurhidayati Endang Arisoesilaningsih +1 位作者 Didik Suprayogo Kumiatun Hairiah 《Journal of Agricultural Science and Technology(A)》 2015年第5期316-324,共9页
Changes in soil quality of sugarcane plantation as a result of changes in land management can not be measured directly, but must be demonstrated by measuring the change in the properties of the ecosystem as an indicat... Changes in soil quality of sugarcane plantation as a result of changes in land management can not be measured directly, but must be demonstrated by measuring the change in the properties of the ecosystem as an indicator. This research aimed to study the effect of the addition of various quality and quantity of organic matter on soil biology (earthworms) and physical quality (aggregate stability, macroporosity and infiltration rate). There were i 5 treatment combinations tested. The first factor is the type of organic matter: (1) cattle manure (CM), (2) filter cake (FC), (3) sugarcane trash (ST), (4) a mixture ofCM + FC and (5) a mixture of CM + ST. The second factor is the application dose of organic matter, which consists of three levels-5, l0 and 15 Mg/ha. The treatments were arranged in a factorial randomized block design with three replicates and one control treatment (without organic matter input). The result of this research showed that the highest population density of earthworms was found in the treatment of ST (78 individuals/m2) and a mixture of CM + ST (84 individuals/m2). The type of organic matter with C/N ratio ranged from 15.5 to 34.7 and cellulose content in 33.3%-40.1% gave better growth of earthworm. The effect of increase in earthworm growth on soil physical improvement is more apparent in the treatment of mixture of low quality and high quality organic matter. The increase of earthworm density and biomass enhanced soil macroporosity (from r = 0.683 to r = 0.606) and infiltration rate (from r = 0.669 to r = 0.756). The results of this study suggest a mixture of CM + ST or ST alone as organic matters, which is recommended to improve soil physical and biological quality of sugarcane land, with the dose application ranged from 10 Mg/ha to 15 Mg/ha. 展开更多
关键词 Quality and quantity of organic matter earthworms physical and biological quality of soil.
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Dynamic Force Reduction and Heat Transfer Improvement for Horizontal Tubes in Large-Particle Gas-Fluidized Beds 被引量:4
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作者 Yusumi Nagahashi John R.Grace +1 位作者 Kok-Seng Lim Yutaka Asako 《Journal of Thermal Science》 SCIE EI CAS CSCD 2008年第1期77-83,共7页
The effects of tube bank configuration on forces and heat transfer were investigated for both two-dimensional and three-dimensional gas fluidized beds. Effective dynamic forces and heat transfer coefficients were meas... The effects of tube bank configuration on forces and heat transfer were investigated for both two-dimensional and three-dimensional gas fluidized beds. Effective dynamic forces and heat transfer coefficients were measured for several tube bank configurations, and it was found that the average forces are smaller than for a single tube. The heat transfer coefficient can be increased by providing sufficient space for particles to descend around both sides of the tube bank. The results provide useful guidelines for optimizing the configuration of tube banks to achieve high heat transfer coefficients while reducing tube erosion due to dynamic forces. 展开更多
关键词 fluidized beds FORCES heat transfer tube arrangement sofid circulation
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