期刊文献+
共找到49篇文章
< 1 2 3 >
每页显示 20 50 100
电站锅炉“四管”防腐防爆工作
1
作者 黄碧波 《通讯世界(下半月)》 2013年第6期103-104,共2页
电站锅炉在运行以及维护中必须做好防腐防爆工作,才能保证工作的安全性,保证电站的可持续发展。本文主要阐述了盘南发电厂锅炉中的水冷壁、省煤器、过热器、再热器四个设备在运行以及维护中的防腐防爆工作。
关键词 电站 锅炉 斯管 防腐 防爆
下载PDF
Debris Flows Risk Analysis and Direct Loss Estimation:the Case Study of Valtellina di Tirano,Italy 被引量:5
2
作者 Jan BLAHUT Thomas GLADE Simone STERLACCHINI 《Journal of Mountain Science》 SCIE CSCD 2014年第2期288-307,共20页
andslide risk analysis is one of the primary studies providing essential instructions to the subsequent risk management process. The quantification of tangible and intangible potential losses is a critical step becau... andslide risk analysis is one of the primary studies providing essential instructions to the subsequent risk management process. The quantification of tangible and intangible potential losses is a critical step because it provides essential data upon which judgments can be made and policy can be formulated. This study aims at quantifying direct economic losses from debris flows at a medium scale in the study area in Italian Central Alps. Available hazard maps were the main inputs of this study. These maps were overlaid with information concerning elements at risk and their economic value. Then, a combination of both market and construction values was used to obtain estimates of future economic losses. As a result, two direct economic risk maps were prepared together with risk curves, useful to summarize expected monetary damage against the respective hazard probability. Afterwards, a qualitative risk map derived using a risk matrix officially provided by the set of laws issued by the regional government, was prepared. The results delimit areas of high economic as well as strategic importance which might be affected by debris flows in the future. Aside from limitations and inaccuracies inherently included in risk analysis process, identification of high risk areas allows local authorities to focus their attention on the “hot-spots”, where important consequences may arise and local (large) scale analysis needs to be performed with more precise cost-effectiveness ratio. The risk maps can be also used by the local authorities to increase population’s adaptive capacity in the disaster prevention process. 展开更多
关键词 Debris flows Risk analysis Economic losses Central Alps ITALY
下载PDF
Efficacy and Safety of a Continuous Wound Catheter in Open Abdominal Partial Hepatectomy
3
作者 车璐 卢欣 裴丽坚 《Chinese Medical Sciences Journal》 CAS CSCD 2017年第3期171-176,共6页
Objective To investigate the efficacy and safety of continuous local anesthetic wound infiltration following open abdominal partial hepatectomy. Methods We performed a prospective, non-randomized, concurrent and con... Objective To investigate the efficacy and safety of continuous local anesthetic wound infiltration following open abdominal partial hepatectomy. Methods We performed a prospective, non-randomized, concurrent and controlled study. Patients undergoing open abdominal partial hepatectomy, according to their willingness, accepted one of the following managements for the postoperative pain: continuous wound catheter (CWC) infiltration, patient-controlled epidural analgesia (PCEA), patient-controlled intravenous analgesia of morphine (PCIAM), and patient-controlled intravenous analgesia of sufentanil (PCIAS). The primary outcome was postoperative visual analogue scale (VAS) scores at rest and on movement. Secondary outcomes included consumption of rescue medication, side effects, and complications associated with postoperative pain management. Results From August 2013 to December 2013, 80 patients were allocated to receive CWC (n=10), PCEA (n=22), PCIAM (n=29), or PCIAS (n=19). After adjusting for age, sex, body mass index, percentage of resected liver, operation time, and Amsterdam Preoperative Anxiety and Information Scale, there was no significant difference in the VAS scores at rest or on movement between Group CWC and the other groups, namely PCEA, PCIAM, and PCIAS, at 4, 12, 48, and 72 hours postoperatively (all P〉0.05). The need for rescue medication was not significantly different between Group CWC and the other three groups at 48 and 72 hours postoperatively (all P〉0.05). There was no significant difference in the incidence of postoperative nausea and vomiting or anal exsufflation time between group CWC and the other three groups (all P〉0.05). No severe adverse effects associated with continuous wound infiltration were observed during the study period. Conclusions CWC has a comparable analgesic effect compared with traditional analgesia methods at most time points postoperatively. CWC is a safe alternative for the postoperative analgesic management of open liver surgery. 展开更多
关键词 continuous wound catheter postoperative pain partial hepatectomy
下载PDF
CONTROL OF GAS EMISSION AT COAL FACE IN CHINA 被引量:2
4
作者 俞启香 郭俊峰 付建华 《Journal of China University of Mining and Technology》 1991年第1期53-63,共11页
All the underground coal mines in China are gassy mines. The gas emission at coal face increasingly grows with the increase of working depth and coal output, for example, the gas emission at a full mechanized coal fac... All the underground coal mines in China are gassy mines. The gas emission at coal face increasingly grows with the increase of working depth and coal output, for example, the gas emission at a full mechanized coal face of mine No. 2 at Yongquan with a daily output of 2. 000t/d is up to 66-72m2/min. Special gas emission phenomena such as gas blowout, gas and coal outburst etc. have occurred at some faces, which threatens the safe production of face. obstructs the growth of productivity and limits the full play of mechanized equipment.In this paper, gas at face is divided, according to its origin, into three constituents, namely , coming from the coal wall, mined coal and goaf;and a formula for calculation is given. Also , the characteristics of the variation of gas emission at coal face, and the influence of mining sequence of a group of seams and supplied air quantity on the gas emission are discussed. Furthermore . based on the regularity of gas emission at coal face from the above three sources, and on the experiences of years, three principles on controlling gas emission at coal face are presented, that are managing the gas on classification basis, harnessing each source separately and comprehensive prevention and control. Finally, technical measures for prevention and treatment of the accumulation of gas in the upper corner of face, at the working place of coal-winning machine and in the bottom trough of conveyor are introduced. 展开更多
关键词 mine safety coal face gas emission PREVENTION CONTROL
下载PDF
Mountain Pastures and Grasslands in the SW Tien Shan,Kyrgyzstan-Floristic Patterns,Environmental Gradients,Phytogeography,and Grazing Impact 被引量:4
5
作者 BORCHARDT Peter SCHICKHOFF Udo +1 位作者 SCHEITWEILER Sabrina KULIKOV Maksim 《Journal of Mountain Science》 SCIE CSCD 2011年第3期363-373,共11页
Vast grasslands are found in the walnut-fruit forest region of southern Kyrgyzstan,Middle Asia.Located above the worldwide unique walnutfruit forests and used for grazing,they play a pivotal role in the mixed mountain... Vast grasslands are found in the walnut-fruit forest region of southern Kyrgyzstan,Middle Asia.Located above the worldwide unique walnutfruit forests and used for grazing,they play a pivotal role in the mixed mountain agriculture of local farmers.Accordingly,these pastures are subject to an increasing utilization pressure reflecting the changing political and social conditions in the transformation process from a Soviet republic to an independent state.A first detailed analysis of mountain pasture vegetation in the Ferghana Range answers the following questions:What are the main plant community types among Kyrgyzstan's mountain pastures? What are the main environmental gradients that shape their species composition? Which phytogeographical distribution types are predominant? How does grazing affect community composition and species richness in these grasslands? Species composition was classified by cluster analysis;underlying environmental gradients were explored using DCA.A dataset of 395 relevés was used for classification,and a subset of 79 relevés was used in a DCA to analyze the correlation between vegetation,environment,and grazing impact.The investigated pastures were classified into four distinctive plant communities.The site factors altitude,heat load,inclination and grazing impact were found to be the major determinants of the vegetation pattern.A significant overlap between floristic composition and structural and spatial properties was shown.The majority of the species pool consisted of Middle Asian endemics and Eurosiberian species.However,disturbance-tolerant species played a significant role with respect to species composition and coverage of the herbaceous layer in vast areas of southern Kyrgyzstan's mountain pastures.In general,an intense grazing impact is clearly reflected by both species composition and structural variables of plant communities.The highly diverse and unique ecosystem is modified by an increasing utilization pressure.In order to maintain vital processes and functioning of this valuable ecosystem-in both economical and ecological terms-,it is indispensable to adopt appropriate pasture management strategies. 展开更多
关键词 Central Asia Classification ENDEMICS Gradient Analysis Grazing impact Middle Asia Pasture Management Ruderals Transformation Process Walnut-fruit forest.
下载PDF
Prevention of explosion in coal mine and management of coal mine gas 被引量:4
6
作者 FURUKAWA Hirofumi TOMITA Shinji 《Journal of Coal Science & Engineering(China)》 2009年第2期215-219,共5页
There are many problems in terms of safe coal production and the sound developmentof the coal industry.Accompanying the intensification and increasing efficiencyof coal production and the conducting of mining operatio... There are many problems in terms of safe coal production and the sound developmentof the coal industry.Accompanying the intensification and increasing efficiencyof coal production and the conducting of mining operations at deeper and more remoteareas of mines,the efficient recovery and utilization of Coal Mine Methane:(CMM) is animportant issue in improving and stabilizing the productivity in the coal mining industry withhigh levels of gas,where the incidence of gas outbursts is increasing.We plan to studyvarious aspects of the development of production technology and characteristics of themine site.This is to establish the technology for highly efficient coproduction coal and gasoperation rate.As a result,the productivity at the coal mine face will increase due to thereduction in gas emissions in the mining face.Effective use of recovered gas can be expectedto reduce global warming by reducing the amount of coal mine methane gas emissionin the air. 展开更多
关键词 coal mine methane coproduction coal and gas global warming
下载PDF
Klatskin tumor treated by inter-disciplinary therapies including stereotactic radiotherapy: A case report
7
作者 Gerhild Becker Felix Momm +7 位作者 Henning Schwacha Norbert Hodapp Henning Usadel Michael GeiBler Annette Barke Annette Schmitt-Gr(a|¨)ff Karl Henne Hubert E. Blum 《World Journal of Gastroenterology》 SCIE CAS CSCD 2005年第31期4923-4926,共4页
In view of the poor prognosis of patients with cholangiocarcinoma (CCC), there is a need for new therapeutic strategies. Inter-disciplinary therapy seems to be most promising. Radiotherapy is an effective alternativ... In view of the poor prognosis of patients with cholangiocarcinoma (CCC), there is a need for new therapeutic strategies. Inter-disciplinary therapy seems to be most promising. Radiotherapy is an effective alternative to surgery for hilar CCC (Klatskin tumors) if an adequate radiation dose can be delivered to the liver hilus. Here, we describe a patient for whom we used a stereotactic radiotherapy technique in the context of an inter-disdplinary treatment concept. We report a 45-year-old patient with a locally advanced Klatskin tumor. Explorative laparotomy showed that the tumor was not resectable. A metallic stent was implanted and the patient was treated by stereotactic radiotherapy using a body frame. A total dose of 48 Gy (3×4 Gy/wk) was administered. Therapy was well tolerated. After 32 too, local tumor recurrence and a chest wall metastasis developed and were controlled by radio-chemotherapy. After more than 56 mo with a good quality of life, the patient died of advanced neoplastic disease. Stereotactic radiotherapy led to a long-term survival of this patient with a locally advanced Klatskin tumor. In the context of inter-disciplinary treatment concepts, this radiotherapy technique is a promising choice of treatment for patients with hilar CCC. 展开更多
关键词 Klatskin tumor Stereotactic radiotherapy Inter-disciplinary treatment
下载PDF
Landform Planation Index Extracted from DEMs: A Case Study in Ordos Platform of China 被引量:3
8
作者 QIAN Yeqing XIONG Liyang +1 位作者 LI Jilong TANG Guoan 《Chinese Geographical Science》 SCIE CSCD 2016年第3期314-324,共11页
Planation surface, a surface that is almost flat, is a kind of low-relief landforms. Planation surface is the consequence of the denudation and planation processes under a tectonic stable condition. The quantitative e... Planation surface, a surface that is almost flat, is a kind of low-relief landforms. Planation surface is the consequence of the denudation and planation processes under a tectonic stable condition. The quantitative expression of the characteristics of planation surface plays a key role in reconstructing and describing the evolutionary process of landforms. In this study, Landform Planation Index(LPI), a new terrain derivative, was proposed to quantify the characteristics of planation surface. The LPIs were calculated based on the summit surfaces formed according to the clustering results of peaks. Ten typical areas in the Ordos Platform located in the central part of the Loess Plateau of China are chosen as the test areas for investigating their planation characteristics with the LPI. The experimental results indicate that the LPI can be effectively used to quantify the characteristics of planation surfaces. In addition, the LPI can be further used to depict the patterns of spatial differentiation in the Ordos Platform. Although the present Ordos Platform area is full of the high-density gullies, its planation characteristics is found to be well preserved. Furthermore, the characteristics of the planation surfaces can also reflect the original morphology of the Ordos Platform before the loess dusts deposition process evolved in this area. The statistical results of the LPI show that there is a gradually increasing tendency along with the increasing of slope gradient of summit surface. It indicates that the characteristics of planation surfaces vary among test areas with different landforms. These findings help to deepen the understanding of planation characteristics of the loess landform and its underlying paleotopography. Results of this study can be also served as an important theoretical reference value for revealing the evolutionary process of loess landform. 展开更多
关键词 Landform Planation Index(LPI) peak summit surface Digital Elevation Model(DEM) Ordos Platform China
下载PDF
Empirical Study About the Application of Knowledge Management in Selected Sector of Industry in Slovakia
9
作者 Dana Kisel'akova 《Chinese Business Review》 2012年第1期92-98,共7页
This study focuses on the analysis of the application of knowledge management in companies in selected sector of industry in Slovakia after Slovakia entering into Euro area in 2009. Based on relevant experience, main ... This study focuses on the analysis of the application of knowledge management in companies in selected sector of industry in Slovakia after Slovakia entering into Euro area in 2009. Based on relevant experience, main conditions and problems associated with the implementation are analyzed through fundamental empirical survey. The necessity of utilization of information and communication technologies, management information systems innovation and long life education in companies are considered in knowledge-based company in knowledge-based society. Further possibilities of application and expected economic effects and benefits on growth and international competitiveness of companies in European Union, Euro area in many fields are outlined in the end of this article as the main aim of this study 展开更多
关键词 knowledge management empirical survey management information system COMPETITIVENESS economic effects and benefits
下载PDF
Pakistan Electronic Media Legal and Regulatory System
10
作者 Muhammad Abrar 《Journalism and Mass Communication》 2014年第1期36-41,共6页
In this paper, the legal and regulatory system of Pakistan media TV will be examined. In the digital era, electronic TV media has become one of Pakistan's fastest growing service industries, but there is still a need... In this paper, the legal and regulatory system of Pakistan media TV will be examined. In the digital era, electronic TV media has become one of Pakistan's fastest growing service industries, but there is still a need for considerable improvement with regard to the laws and regulations governing the activity. It defines the Pakistan electronic regulatory process and the relevant media laws. After that, it discusses enforcement mechanism operating in Pakistan, Lastly, it suggests some recommendations. 展开更多
关键词 MEDIA REGULATION ENFORCEMENT BROADCASTING Pakistan TELEVISION
下载PDF
Bycatch of Shrimp Fishery in the West Coast of Madagascar: Case of Otolithes argenteus (Cuvier, 1830)
11
作者 Isabelle Herisoa Hantanirina Fanomezantsoa Randriarilala +4 位作者 Rivo Nirina Rabearimisa Faniriantsoa Randriaharimino Randriamiarisoa Georges Rafomanana Jean de Neupomuscene Rakotozandriny 《Journal of Environmental Science and Engineering(A)》 2016年第5期230-240,共11页
An increasing interest of the economic operators on the bycatch of shrimp fishery endangers bycatch species to over-exploitation risks. This study provides a better knowledge regarding to the current status of one maj... An increasing interest of the economic operators on the bycatch of shrimp fishery endangers bycatch species to over-exploitation risks. This study provides a better knowledge regarding to the current status of one major component of the bycatches Otolithes argenteus (O. argenteus) caught in the shrimp fishery area along the West coast of Madagascar using the morphometric analysis. Individual body weight and body measurement were carried out on 565 specimens collected from the sale's society of seafood (SOPROMER) in the Capital city. Results show a high proportion of small fishes like as immature young individuals. A "negative allometry" growth type within the juveniles to become "isometric allometry" for the adult, large size was observed. Marine environment is favorable to the development for the whole population of the O. argenteus species. The morphometry approach helped to better understanding of the characteristics and the operating status of the O. argenteus population thus constitute as a tool in establishing a sustainable fisheries management strategy in Madagascar. 展开更多
关键词 Otolith argenteus MORPHOMETRY BYCATCH West coast of Madagascar.
下载PDF
Driving Smartization Through Intelligent Transport 被引量:1
12
作者 Francesco Bifulco Cristina C. Amitrano Marco Tregua 《Chinese Business Review》 2014年第4期243-258,共16页
Smart cities initiatives are developing all over the world, due to their support in favouring a better provision of services, in connection with the aim of achieving efficiency in cities management. More and more big ... Smart cities initiatives are developing all over the world, due to their support in favouring a better provision of services, in connection with the aim of achieving efficiency in cities management. More and more big corporations are interested in this topic to develop their businesses, as several issues are linked to these projects, like environment, water management, energy policies, education, culture, and so on. In literature these issues, known as drivers, were also related to sustainability aims which could be reached through the accomplishment of better performances within environment, economy, and society. This study synthesizes all the different drivers identified by scholars and industry players in a model, in order to use it as a framework to depict the linkages among the various smart cities projects. Since transport resulted as one of the most considered drivers in the analyzed contributions, the research questions were delineated to describe its role in the different phases of smart initiatives, and to understand if it could encourage and enable the other drivers' development. The multiple case study was chosen as the fittest methodological approach and it was conducted with the selection of three smart cities, one for each of the most cited platform models developed by industry players, which had started transport initiatives at least three years ago: Singapore (IBM), Amsterdam (Accenture), and San Francisco (Microsoft). The analysis of the official documents set up by city departments and by the industry players showed transport as a driving force in smart cities projects which conveys a smart approach to different domains, especially energy savings, environment, and safety. The results also showed smart mobility as a pivot in stimulating investments and citizens' participation on different city drivers, especially as it concerns environment and services to both citizens and businesses. Smart transport initiatives, hardware and software infrastructures, technological devices, and people participation to smartization were closely interrelated in smart cities projects and they could be successfully used to achieve sustainability aims for different stakeholders. 展开更多
关键词 smart cities management platform models transport driver sustainable mobility ICTS
下载PDF
On the Edge of Malfeasance: Informal African Immigrant Traders in the/ohannesburg Inner City, South Africa
13
作者 Inocent Moyo Trynos Gumbob 《Sociology Study》 2014年第4期323-333,共11页
Admittedly, the stratospheric rise of Informal African Immigrant Traders (IAIT) in the Johannesburg inner city within a climate of discrimination, harassment, hostility, and xenophobia has engendered survival strate... Admittedly, the stratospheric rise of Informal African Immigrant Traders (IAIT) in the Johannesburg inner city within a climate of discrimination, harassment, hostility, and xenophobia has engendered survival strategies which border on the illegal and underground. Based on an in-depth interview study of 40 IAIT, operating in the Johannesburg inner city and specialising in clothes, cellphone and accessories, household goods, fruits and vegetables, and a courier company, this paper posits that the registered and unregistered IAIT operate side by side with the latter operating from undesignated sites, either bribing or deceitful evading the Johannesburg Metropolitan Police (JMP). Is this the characteristic of IAIT in the Johannesburg inner city? Ostensibly, the success of challenging the institutional regulatory regime points to the possibility of African immigrant traders existing on the edge of impropriety or lawlessness. To this end, there is a need for comprehensive policy initiatives starting from the national and cascading to the provincial and municipality levels that will effectively address and manage urban informality, including the activities of the IAIT, failing which these will fuel operations outside the regulatory regimes and the mushrooming of the underground economic activities. 展开更多
关键词 African immigrant traders urban informality discrimination JOHANNESBURG South Africa
下载PDF
Leadership in Safety and Regulatory Oversight: Defining the Leadership Framework in Pakistan Nuclear Regulatory Authority
14
作者 N. Afghan S.A. Mallick M.A. Habib 《Journal of Energy and Power Engineering》 2011年第6期528-535,共8页
The purpose of this paper is to define a leadership competency framework for nuclear within Pakistan Nuclear Regulatory Authority (PNRA). It provides arguments for a more holistic approach towards leadership develop... The purpose of this paper is to define a leadership competency framework for nuclear within Pakistan Nuclear Regulatory Authority (PNRA). It provides arguments for a more holistic approach towards leadership development in nuclear organization. It further provides leadership framework that can be used (adapted/adopted) by other regulatory bodies for developing leadership within the organization. It is expected that new countries embarking on nuclear power programme will especially find this interesting and useful as they will also face similar challenges as faced by Pakistan Nuclear Regulatory Authority during its formative year. Paper further provides insights into the process of leadership development in organization. It is suggested that an integrated approach is important to develop nuclear leadership within the organization. It was also found that an effective leadership development program is not only long process but requires commitment from top leadership. Leadership gap analysis, providing open feedback and action learning project were important elements for leadership development. 展开更多
关键词 PNRA NRC leadership.
下载PDF
Quality of life after three kinds of esophagectomy for cancer 被引量:18
15
作者 Jian Zeng Jin-Shi Liu 《World Journal of Gastroenterology》 SCIE CAS CSCD 2012年第36期5106-5113,共8页
AIM: TO evaluate quality of life (QOL) following Ivor Lewis, left transthoracic, and combined thoracoscopic/ laparoscopic esophagectomy in patients with esopha- geal cancer. METHODS: Ninety patients with esophagea... AIM: TO evaluate quality of life (QOL) following Ivor Lewis, left transthoracic, and combined thoracoscopic/ laparoscopic esophagectomy in patients with esopha- geal cancer. METHODS: Ninety patients with esophageal cancer were assigned to Ivor Lewis (/7 = 30), combined thora- coscopic/laparoscopic (n = 30), and left transthoracic (n = 30) esophagectomy groups. The QOL-core 30 questionnaire and the supplemental QOL-esophageal module 18 questionnaire for patients with esophageal cancer, both developed by the European Organization for Research and Treatment of Cancer, were used to evaluate patients' QOL from 1 wk before to 24 wk after surgery. RESULTS: A total of 324 questionnaires were collect- ed from 90 patients, 36 postoperative questionnaires were not completed because patients could not be contacted for follow-up visits. QOL declined markedly in all patients at 1 wk postoperatively: preoperative and 1-wk postoperative global QOL scores in the Ivor Lewis, combined thoracoscopic/laparoscopic, and left transthoracic groups were 80.8 ± 9.3 vs 32.0 ± 16.1 (P 〈 0.001), 81.1±9.0 vs 53.3 ± 11.5 (P 〈 0.001), and 83.6 ± 11.2 vs 46.4 ± 11.3 (P 〈 0.001), respectively. Thereafter, QOL recovered gradually in all patients. Patients who underwent Ivor Lewis esophagectomy showed the most pronounced decline in QOL; global scores were lower in this group than in the combined thoracoscopic/laparoscopic (P 〈 0.001) and left trans- thoracic (P 〈 0.001) groups at 1 wk postoperatively and was not restored to the preoperative level at 24 wk postoperatively. QOL declined least in patients under- going combined thoracoscopic/laparoscopic esopha- gectomy, and most indices had recovered to preopera- tive levels at 24 wk postoperatively. In the Ivor Lewis and combined thoracoscopic/laparoscopic groups, pain and physical function scores were 78.9 ± 18.5 vs 57.8 ± 19.9 (P 〈 0.001) and 59.3 ± 16.1 vs 70.2 ± 19.2 (P = 0.02), respectively, at 1 wk postoperatively and 26.1 ± 28.6 vs 9.5 ± 15.6 (P = 0.007) and 88.4 ± 10.5 vs 95.8 ± 7.3 (P = 0.003), respectively, at 24 wk postop- eratively. Scores in the left transthoracic esophagecto- my group fell between those of the other two groups. CONCLUSION: Compared with Ivor Lewis and left transthoracic esophagectomies, combined thoraco- scopic/laparoscopic esophagectomy enables higher postoperative QOL, making it a preferable surgical ap- proach for esophageal cancer. 展开更多
关键词 Esophageal cancer Quality of life Thora-coscope LAPAROSCOPE ESOPHAGECTOMY
下载PDF
Water blocking effect caused by the use of hydraulic methods for permeability enhancement in coal seams and methods for its removal 被引量:9
16
作者 Liu Qian Guo Yusen +2 位作者 An Fenghua Lin Luyao Lai Yongming 《International Journal of Mining Science and Technology》 SCIE EI CSCD 2016年第4期615-621,共7页
To research techniques for removing the water blocking effect caused by hydraulic applications in coal seams,the use of surfactants is proposed,based on the mechanics of the water blocking effect.Centrifugal experimen... To research techniques for removing the water blocking effect caused by hydraulic applications in coal seams,the use of surfactants is proposed,based on the mechanics of the water blocking effect.Centrifugal experiments were used to validate the effects of using surfactants;the results show that after dealing with vacuum saturation with water,the volume of micropores decreases,which results in a larger average pore size,and the volume of transitional pores,mesopores,macropores and total pores increases.Based on the distribution of pore size,the operation mode of ‘‘water infusion after gas extraction,then continuing gas extraction" is recommended to improve the volume of coal mine gas drainage.When the reflectance of vitrinite in coal samples is less than 1,using the surfactants Fast T,1631,APG,BS can mitigate the damage caused by the water blocking effect.But when the reflectance of vitrinite is larger than 1.4,the damage caused by the water blocking effect can be increased.When the surfactant CMC is used in hydraulic applications,the capillary forces of coal samples are almost negative,which means the capillary force is in the same direction as the gas extraction.The direction of capillary forces benefits the gas flow.So,using CMC can play an active role in removing the water blocking effect.Centrifugal experiments confirm that using CMC can effectively remove the water blocking effect,which has a beneficial effect on improving the gas drainage volume. 展开更多
关键词 Gas extraction Hydraulic measures Water blocking effect Capillary force Surfactant
下载PDF
Managing Salinity in Tunisian Oases
17
作者 Mohamed Hachicha Imed Ben Aissa 《Journal of Life Sciences》 2014年第9期775-782,共8页
The Tunisian oases face serious problems of waterlogging and salinization caused by mismanagement of water and soil resources and the reduced discharge of drainage water. The oases space is based on a fragile balance ... The Tunisian oases face serious problems of waterlogging and salinization caused by mismanagement of water and soil resources and the reduced discharge of drainage water. The oases space is based on a fragile balance between water, soil and man, which is now changed by modem irrigation and drainage systems. The oases pump most of their water from deep aquifers and only to a small degree from shallow aquifers. The quality of the irrigation water and the presence of a shallow saline water table are the main causes of salinization of the oases. Concerning the salt-affected landscapes and hydro-saline dynamic, the authors distinguish an equilibrium dynamic of salts to the parcel which depends on water management, and an equilibrium dynamic at the level of the basin watershed which is powered by drilling and ending in hypersaline depressions. For the management of salinization and waterlogging, a combination of agricultural management techniques are used, the first being modem methods of irrigation and drainage. Other, less used methods are sandy amendment, the reuse of drainage waters, geothermal waters and of treated wastewater. 展开更多
关键词 WATER IRRIGATION drainage SALINITY oases Tunisia.
下载PDF
Flow-Induced Acoustic Resonances in Exhaust Gas Economizer Tube Banks 被引量:1
18
作者 Satoru Okamoto 《Journal of Mechanics Engineering and Automation》 2013年第3期159-167,共9页
To investigate the conditions under which acoustic resonances occur, staggered arrays of closely spaced rigid tubes were tested in a wind tunnel under various flow velocities. The author investigated the Strouhal numb... To investigate the conditions under which acoustic resonances occur, staggered arrays of closely spaced rigid tubes were tested in a wind tunnel under various flow velocities. The author investigated the Strouhal numbers at which flow periodicities occur, the relation between these Strouhal numbers and those at which acoustic resonances occur, and the effects of Reynolds number and longitudinal tube spacings on the occurrence of acoustic resonance. This investigation showed the following: (1) Acoustic resonance can be produced at a frequency well removed from that of vortex shedding. The results also show evidence of vortex shedding and acoustic resonance existing simultaneously but at different frequencies. (2) Acoustic resonance behavior is consistent with that of a self-excited system. (3) A new model of this phenomenon provides an improved procedure for avoiding acoustic resonances in closely spaced tube banks. 展开更多
关键词 Flow-induced vibration flow measurements VORTEX aerodynamic acoustics resonance tube arrays.
下载PDF
Theoretical Study on Field Emission Patterns of the Nanotube
19
作者 HU Chen guo, WANG Wan lu, LIAO Ke jun, WANG Hao, XIAO Jin long (Department of Applied Physics,Chongqing University,Chongqing 400030,CHN) 《Semiconductor Photonics and Technology》 CAS 2003年第4期238-241,共4页
The distributions of the electrical potential and field have been given from Maxwells field equations.The results show that there exists very strong electric field intensity on the tip of the nanotube,and the intensit... The distributions of the electrical potential and field have been given from Maxwells field equations.The results show that there exists very strong electric field intensity on the tip of the nanotube,and the intensity decays rapidly as the distance increases away from the tip. The strong electric field intensity on the tip is consistent with the low threshold voltage under the electric field emission from a nanotube. The calculation also revealed that the higher the aspect ratio is,the stronger the electric field intensity on the tip of the nanotube will be,if the distance and voltage between the cathode and the anode do not change, which predicts the lower threshold voltage under the field emission. 展开更多
关键词 NANOTUBE Field emission Maxwell's field equation
下载PDF
Gas pipeline explosion resistance technology 被引量:1
20
作者 Zhao ZHU Zhen-Yuan JIA Kui-Jun WANG 《Journal of Coal Science & Engineering(China)》 2013年第3期353-357,共5页
Based on the features and requirements of gas drainage system, an optimized explosion resistance technology is done after a comprehensive analysis and research about the triple IR (Infrared Ray) flame detection tech... Based on the features and requirements of gas drainage system, an optimized explosion resistance technology is done after a comprehensive analysis and research about the triple IR (Infrared Ray) flame detection technology, explosion resistance valve technology and explosion resistance control technology. An intelligent PLC (Programmable Logic Controller) resistance control system is designed which can cut offthe gas branch quickly and accurately, and the controller have automatic pressure maintaining function, valve rotation limit function, remote and local control interlock function. The reliability and rationality of explosion resistance technology is verified by gas pipeline explosion propagation and resistance simulation test. Overall response time of explosion resistance system is less than 100ms, and the spread of fire in gas pipeline can be prevented effectively. 展开更多
关键词 explosion resistance technology flame detection fast shut-off valve intelligent control
下载PDF
上一页 1 2 3 下一页 到第
使用帮助 返回顶部