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Science China(Technological Sciences) 2013年第8期56卷 1651-1656页

作者： LU YuanWei LI XiaoLi LI Qiang WU YuTing MA ChongFang Key Laboratory of Enhanced Heat Transfer and Energy Conservation College of Environmental and Energy EngineeringBeijing University of Technology

In order to get the Natural convection heat transfer mechanism of molten salt, the experimental investigation of Natural convective heat transfer of LiNO3was studied after it was simulated by numerical calculation. Experiment was carried out on the nat-ural convection heat transfer of air and water around the fine wire using the method of Joule heating. The results showed that the Natural convection heat transfer of air and water around the fine wire agreed well with Fand's correlation. Based on the aforementioned experiment, the Natural convection heat transfer of molten salt LiNO3was studied by experiment and the same results were got. Therefore, the Natural convection heat transfer of molten salt can be calculated by Fand's correlation, which takes into consideration the effect of viscosity dissipation.

关键词： Joule heating Natural convection numerical simulation molten salt

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Delimitation and Zoning of Natural Ecological Spatial Boundary Based on GIS

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Asian Agricultural Research 2019年第5期11卷 40-45页

作者： Yonghao WANG Hengji LI Jun REN Gansu Academy of Natural Resources Planning Lanzhou730000China Global Change Research Information Center Lanzhou Information CenterChineseAcademy of SciencesLanzhou730000 Qinghai University Xining810016China

In order to improve the control of land use in China,taking Sunan Yugur Autonomous County in the Qilian Mountains area as an example,this paper explores the method of national ecological space delimitation and zoning based on ARCGIS platform. Three kinds of space division techniques are formed to unify Natural resources survey data,carry out land spatial suitability evaluation,delimit three kinds of space and optimize Natural ecological space division. According to existing laws in China,based on ecological protection red line,Natural ecological space is divided into ecological protection red line and general ecological space. According to the regulation requirements and the functional division of various protected areas,the red line area of ecological protection is divided into core protected area,ecological restoration area,traditional utilization and recreation area with the area of 3 947. 28,3 216. 89 and 6 936. 56 km2,respectively. In view of the prominent problems in the process of delimitation and zoning of Natural ecological space,some suggestions are put forward,such as unification of chassis,optimization of ecological protection red line and coordination and unification of management boundary.

关键词： Territorial space Natural ecological space Ecological protection red line General ecological space

Natural Gas Utilization and Policy Incentives under the Economic “New Normal”

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China Oil & Gas 2019年第4期26卷 38-46页

作者： Xiong Wei Gas & Economics Research Institute PetroChina Southwest Oil & Gasfield Company

Since the Chinese economy entered the“new normal”stage,Natural gas consumption in China has been sluggish and supply and demand have been relaxed.At the same time,environmental protection policies are intensified and the marketization process is accelerated.Many factors have intertwined with each other and affected China’s Natural gas consumption.Judging from China’s economic growth,structural adjustment of and energy consumption,and the scale and structure of global Natural gas utilization,we believe that there is still significant rise of Natural gas consumption in China.However,there are still many problems that hinders the utilization of Natural gas,which may be solved by policies and market-oriented reforms.Taking Natural gas-based distributed energy as an example,this paper analyzes the change and influence of relevant policies,and puts forward proposed incentive policies to promote the utilization of Natural gas in China under the economic“new normal”.

关键词： New normal Natural gas utilization Policies

Natural Monopoly and Mixed Ownership Reform--Based on Natural Experiment and Cost Function Analysis Method

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China Economist 2018年第5期13卷 60-83页

作者：陈林 Institute of Industrial Economics Jinan University Institute of Industrial Economics Chinese Academy of Social Sciences

Despite a multitude of theoretical discussions on China's mixed ownership reform, very few studies have addressed realistic questions concerning the implementation of the reform. The Resolutions of the Third Plenum of the 18 th CPC Central Committee and other reform strategies have outlined the reform of sectors with Natural monopoly, including urban public utility sectors. The question is how mixed ownership reform should be carried out in sectors of Natural monopoly, or which public utilities sectors should enjoy priority of mixed ownership reform. To answer this question, this paper employs data of large public utility enterprises in China from 1998 to 2008, and estimates the Natural monopoly attribute at the industry level and corporate total factor productivity(TFP) using cost function analysis method excluding the impact of product price factor. Based on the difference-indifferences-in-differences(DDD) method of Natural experiment, an empirical test is carried out for the relationship among Natural monopoly, mixed ownership reform and corporate productivity. Our results suggest that:(1) Statistically, mixed ownership reform cannot significantly increase corporate TFP in sectors with Natural monopoly;(2) mixed ownership reform should not be carried out indiscriminately on a nationwide basis and for all public utilities sectors. Such an attempt of reform without distinguishing Natural monopoly and the level of competitiveness is fraught with policy uncertainties;(3) relative to sectors with Natural monopoly, corporate productivity in competitive sectors after mixed ownership reform will improve more significantly and enjoy greater "policy dividends" of institutional reform. Therefore, mixed ownership reform should be carried out first in competitive sectors.

关键词： mixed ownership reform Natural monopoly cost function Natural experiment,difference-in-differences-in-differences(DDD)method

China Natural Gas Industry Prosperity Index in the Third Quarter of 2018 Analysis Report

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China Oil & Gas 2018年第6期25卷 56-58页

作者： Shen Xilin Li Yi China Natural Gas Industry Prosperity Index Research Center Southwest Petroleum University

The statistics of the China Natural gas industry prosperity index show that:China Natural gas industry prosperity index reached 65.77 in the third quarter of 2018,a relatively prosperous state;the prosperity index of Natural gas production enterprises reached 67.37,also a relatively prosperous state.Natural gas sales companies' prosperity index reached 65.29,a relatively prosperous state;the prosperity trend index of the Natural gas industry in the coming year was set at 85.33,and the Natural gas industry in the coming year will be in a very prosperous state.

关键词： China Natural Gas industry Index Analysis Report

Constructing an International Cooperation System of Natural Gas in Northeast Asia

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China Oil & Gas 2019年第4期26卷 47-55页

作者： He Runmin Luo Lingrui Cao Qiang PetroChina Southwest Oil & Gasfield Company

Supply&demand pattern and development trends of Natural gas in Northeast Asia The consumption of Natural gas in Northeast Asia is over half that of the Asia-Pacific region Since 2010,with the global economic recovery,the long-term upward trend of Natural gas demand has been restored.The annual year-onyear growth rate has been maintained at about 2%and the annual output has been higher than the consumption.2017 witnessed world Natural gas consumption reaches 367.04 billion m3,representing a year-on-year growth rate of 3%,higher than the average growth rate of 2.2%in the past 10 years.

关键词： Natural gas Northeast Asia economic recovery

Natural history of chronic hepatitis B:Phases in a complex relationship

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World Journal of Gastroenterology 2014年第30期20卷 10395-10404页

作者： Catherine MN Croagh John S Lubel Department of Gastroenterology and Hepatology Eastern Health3128 VictoriaAustralia Eastern Health Clinical School Monash UniversityMelbourne3800 VictoriaAustralia

Chronic hepatitis B(CHB)is a condition of globalprevalence and its sequelae include cirrhosis and hepatocellular carcinoma.The Natural history of CHB isa complex interplay of virological,environmental andhost factors.The dynamic relationship between thevirus and host evolves over the duration of the infection and different phases of the disease have been observed and described.These have been conceptualizedin terms of the state of balance between the host immune system and the hepatitis B virus and have beengiven the labels immune tolerant,immune clearance,immune control and immune escape although othernomenclature is also used.Host factors,such as age atinfection,determine progression to chronicity.Virological factors including hepatitis B viral load,mutationsand genotype also have an impact on the adverseoutcomes of the infection,as do hepatotoxic cofactorssuch as alcohol.Our understanding of the Natural history of CHB has evolved significantly over the past fewdecades and characterizing the phase of disease ofCHB remains an integral part of managing this virus in the clinic.

关键词： Hepatitis B Fibrosis Natural history Hepatitis B e

Laparoscopic Natural orifice specimen extraction-colectomy: A systematic review

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World Journal of Gastroenterology 2014年第36期20卷 12981-12992页

作者： Albert M Wolthuis Anthony de Buck van Overstraeten André D'Hoore Department of Abdominal Surgery University Hospital Leuven 3000 Leuven Belgium

Over the last 20 years, laparoscopic colorectal surgery has shown equal efficacy for benign and malignant colorectal diseases when compared to open surgery. However, a laparoscopic approach reduces postoperative morbidity and shortens hospital stay. In the quest to optimize outcomes after laparoscopic colorectal surgery, reduction of access trauma could be a way to improve recovery. To date, one method to reduce access trauma is Natural orifice specimen extraction(NOSE). NOSE aims to reduce access trauma in laparoscopic colorectal surgery. The specimen is delivered via a Natural orifice and the anastomosis is created intracorporeally. Different methods are used to extract the specimen and to create a bowel anastomosis. Currently, specimens are delivered transcolonically, transrectally, transanally, or transvaginally. Each of these NOSEprocedures raises specific issues with regard to operative technique and application. The presumed benefits of NOSE-procedures are less pain, lower analgesia requirements, faster recovery, shorter hospital stay, better cosmetic results, and lower incisional hernia rates. Avoidance of extraction site laparotomy is the most important characteristic of NOSE. Concerns associated with the NOSE-technique include bacterial contamination of the peritoneal cavity, inflammatory response, and postoperative outcomes, including postoperative pain and the functional and oncologic outcomes. These issues need to be studied in prospective randomized controlled trials. The aim of this systematic review is to describe the role of NOSE in minimally invasive colorectal surgery.

关键词： Laparoscopy Colorectal surgery Natural orifice spe

Natural orifice transesophageal thoracoscopic surgery:A review of the current state

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World Journal of Gastrointestinal Endoscopy 2010年第1期2卷 3-9页

作者： Brian G Turner Denise W Gee Gastrointestinal Unit Massachusetts General Hospital55 Fruit StreetBostonMA 02114United States Department of Surgery Massachusetts General Hospital15 Parkman StreetBostonMA 02114United States

Since the concept of Natural Orifice Translumenal Endoscopic Surgery(NOTES) was introduced,it has continued to gain significantly in popularity and enthusiasm for its potential clinical applications.The ability to perform conventional laparoscopic and thoracoscopic procedures without the creation of scars and perhaps faster and less painful recovery has prompted a worldwide devotion to further this field.While intraabdominal NOTES has rapidly transitioned from animal models to human trials,applying the NOTES concept to perform thoracic procedures has been slower to gain momentum.The goal of this review is to summarize the current state of transesophageal NOTES thoracoscopy by looking at its potential for diagnostic and therapeutic interventions as well as the challenges in transitioning to human trials.

关键词： Natural orifice translumenal endoscopic surgery Transesophageal Thoracoscopy Mediastinoscopy Esophagotomy Natural orifice Endoscopy

Analysis of Combined Natural Convection and Radiation Heat Transfer in a Partitioned Rectangular Enclosure with Semitransparent Walls

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Transactions of Tianjin University 2019年第5期25卷 472-487页

作者： Liqun Zhou Jiaying Liu Qunwu Huang Yiping Wang School of Chemical Engineering and Technology Tianjin UniversityTianjin 300350China Shanghai Urban Construction Material Co. Ltd Shanghai 200063China

In this paper, we present a two-dimensional numerical analysis of the conjugate Natural convection and radiation heat transfer in a double-space enclosure with two semitransparent walls. Two kinds of boundary conditions are considered, the rst being the isothermal process of the opaque wall, and the other the incidence of a constant radiation ux in the left semitransparent wall. The renormalization group k ε model is adopted to simulate the turbulent ow in the enclosure. To compute the radia- tion heat transfer in a semitransparent medium, the discrete ordinates model is used. We compare the behaviors of enclosures with single and double semitransparent walls and determine the di erence in the results obtained for semitransparent and opaque partitions. The results indicate that a semitransparent partition facilitates a reduction in the heat loss or obtains a higher temperature distribution. The transmittance of a semitransparent wall has a great e ect on the thermal and ow char- acteristics in an enclosure. The change of wall temperature is found to be signi cant when the thermal conductivity values range from 0.05 to 0.5 W/(m K), and to be small when ranging from 0.5 to 10 W/(m K). These conclusions are helpful for green design and energy saving in solar buildings.

关键词： Natural convection Enclosure Semitransparent wall Thermal conductivity Transmittance