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Heat-spreading analysis of a heat sink base embedded with a heat pipe

B. V. BORGMEYER, H. B. MA,

《能源前沿(英文)》 2010年 第4卷 第2期   页码 143-148 doi: 10.1007/s11708-010-0013-1

摘要: A simplified model predicting the heat transfer performance of a heat sink base with a high thermal conductivity was developed. Numerical analysis was performed using the commercial software FLUENT. The investigation indicates that for heat sink bases with a high effective thermal conductivity, such as the base embedded with a typical heat pipe, the entire heat sink can be modeled as a flat plate with a uniform temperature and an effective convection heat transfer coefficient. This simplified model can be used to determine the heat transfer performance of a heat sink embedded with a typical heat pipe or vapor chamber.

关键词: heat pipe     heat sink     microprocessor heat removal    

海洋渔业碳汇及其扩增战略

唐启升,刘 慧

《中国工程科学》 2016年 第18卷 第3期   页码 68-73 doi: 10.15302/J-SSCAE-2016.03.011

摘要:

本文介绍了海洋渔业碳汇和碳汇渔业的定义、研究现状、问题及技术需求。与林业碳汇比较结果表明,海洋渔业碳汇不仅有高效的特性,还有扩增的潜质。为此,提出海洋渔业碳汇扩增对策建议,主要包括:查明我国海洋渔业碳汇潜力及动态机制;大力发展以海水养殖为主体的碳汇渔业;加强近海自然碳汇及其环境的养护和管理;实施相应的渔业碳汇扩增工程建设,促进环境友好型水产养殖业发展。

关键词: 海洋渔业碳汇     碳汇渔业     碳汇扩增     养护和管理     贝藻养殖    

Effect of / molecular structures on pyrolysis performance and heat sink of decalin isomers

《化学科学与工程前沿(英文)》 2023年 第18卷 第1期 doi: 10.1007/s11705-023-2375-z

摘要: Decalin is considered as an important compound of high-energy-density endothermic fuel, which is an ideal on-board coolant for thermal management of advanced aircraft. However, decalin contains two isomers with a tunable composition, and their effects on the pyrolysis performance, such as the heat sink and coking tendency have not been demonstrated. Herein, we investigated the pyrolysis of decalin isomers, i.e., cis-decalin, trans-decalin and their mixtures (denoted as mix-decalin), in order to clarify the effects of the cis-/trans-structures on the pyrolysis performance of decalin fuels. The pyrolysis results confirmed that conversion of the tested fuels (600–725 °C, 4 MPa) decreased in the order cis-decalin > mix-decalin > trans-decalin. Detailed analyses of the pyrolysis products were used to compare the product distributions from cis-decalin, mix-decalin and trans-decalin, and the yields of some typical components (such as cyclohexene, 1-methylcyclohexene, benzene and toluene) showed significant differences, which could be ascribed to deeper cracking of cis-decalin. Additionally, the heat sinks and coking tendencies of the decalins decreased in the order cis-decalin > mix-decalin > trans-decalin. This work demonstrates the relationship between the cis/trans structures and the pyrolysis performance of decalin, which provides a better understanding of the structure-activity relationships of endothermic hydrocarbon fuels.

关键词: endothermic fuel     decalin     pyrolysis     heat sink     molecular structure    

Effects of radiation and heat source/sink on unsteady MHD boundary layer flow and heat transfer over

Krishnendu Bhattacharyya

《化学科学与工程前沿(英文)》 2011年 第5卷 第3期   页码 376-384 doi: 10.1007/s11705-011-1121-0

摘要: In this paper, an investigation is made to study the effects of radiation and heat source/sink on the unsteady boundary layer flow and heat transfer past a shrinking sheet with suction/injection. The flow is permeated by an externally applied magnetic field normal to the plane of flow. The self-similar equations corresponding to the velocity and temperature fields are obtained, and then solved numerically by finite difference method using quasilinearization technique. The study reveals that the momentum boundary layer thickness increases with increasing unsteadiness and decreases with magnetic field. The thermal boundary layer thickness decreases with Prandtl number, radiation parameter and heat sink parameter, but it increases with heat source parameter. Moreover, increasing unsteadiness, magnetic field strength, radiation and heat sink strength boost the heat transfer.

关键词: MHD boundary layer     unsteady flow     heat transfer     thermal radiation     heat source/sink     shrinking sheet     suction/injection    

On secondary new particle formation in China

Markku Kulmala,Tuukka Petäjä,Veli-Matti Kerminen,Joni Kujansuu,Taina Ruuskanen,Aijun Ding,Wei Nie,Min Hu,Zhibin Wang,Zhijun Wu,Lin Wang,Douglas R. Worsnop

《环境科学与工程前沿(英文)》 2016年 第10卷 第5期 doi: 10.1007/s11783-016-0850-1

摘要: Formation of new atmospheric aerosol particles is a global phenomenon that has been observed to take place in even heavily-polluted environments. In China, new particle production has been observed at very high pollution levels (condensation sink about 0.1s ) in several megacities. A holistic scientific understanding on the atmospheric phenomena associated with air quality as a whole, as well as on the connection between air quality and climate, is lacking at the moment.With a network of observation stations, we will be able to understand the interactions and feedbacks associated with the urban pollution mixture, and ultimately, are ready to make targeted strategies for the pollution control. This paper summaries the recent advances in studying secondary new aerosol formation in China and shows how increased process-level understanding will help us to understand air quality-climate-weather interactions and how the feedbacks and interactions affect the air quality in highly-polluted environments such as those frequently encountered in Chinese megacities. Formation of new atmospheric aerosol particles is a global phenomenon that has been observed to take place in even heavily-polluted environments. However, in all environments there appears to be a threshold value of the condensation sink (due to pre-existing aerosol particles) after which the formation rate of 3 nm particles is no longer detected. In China, new particle production has been observed at very high pollution levels (condensation sink about 0.1 s ) in several megacities, including Beijing, Shanghai and Nanjing as well as in Pearl River Delta (PRD). Here we summarize the recent findings obtained from these studies and discuss the various implications these findings will have on future research and policy.

关键词: Aerosol particles     Heavily-polluted environments     Condensation sink     New particle production     Megacities    

Development of a cloud condensation nuclei (CCN) counter using a laser and charge-coupled device (CCD

Mikyung PARK, Jinkwan OH, Kihong PARK

《环境科学与工程前沿(英文)》 2011年 第5卷 第3期   页码 313-319 doi: 10.1007/s11783-011-0346-y

摘要: A continuous flow streamwise thermal gradient cloud condensation nuclei (CCN) counter with an aerosol focusing and a laser-charge-coupled device (CCD) camera detector system was developed here. The counting performance of the laser-CCD camera detector system was evaluated by comparing its measured number concentrations with those measured with a condensation particle counter (CPC) using polystyrene latex (PSL) and NaCl particles of varying sizes. The CCD camera parameters (e.g. brightness, gain, gamma, and exposure time) were optimized to detect moving particles in the sensing volume and to provide the best image to count them. The CCN counter worked well in the particle number concentration range of 0.6–8000 #·cm and the minimum detectable size was found to be 0.5 μm. The supersaturation in the CCN counter with varying temperature difference was determined by using size-selected sodium chloride particles based on K?hler equation. The developed CCN counter was applied to investigate CCN activity of atmospheric ultrafine particles at 0.5% supersaturation. Data showed that CCN activity increased with increasing particle size and that the higher CCN activation for ultrafine particles occurred in the afternoon, suggesting the significant existence of hygroscopic or soluble species in photochemically-produced ultrafine particles.

关键词: aerosol     cloud condensation nuclei (CCN) counter     ultrafine particle    

features of new particle formation events at background sites in China and their influence on cloud condensation

Xiaojing SHEN,Junying SUN,Xiaoye ZHANG,Yangmei ZHANG,Lu ZHANG,Ruxia FAN

《环境科学与工程前沿(英文)》 2016年 第10卷 第5期 doi: 10.1007/s11783-016-0833-2

摘要: New particle formation (NPF) event at multi rural sites in China Identifying the characteristics of NPF event Comparing NPF event between clean and polluted conditions Quantifying contribution to the cloud condensation nuclei Implication of climate and air quality Long-term continuous measurements of particle number size distributions with mobility diameter sizes ranging from 3 to 800 nm were performed to study new particle formation (NPF) events at Shangdianzi (SDZ), Mt. Tai (TS), and Lin’an (LAN) stations representing the background atmospheric conditions in the North China Plain (NCP), Central East China (CEC), and Yangtze River Delta (YRD) regions, respectively. The mean formation rate of 3-nm particles was 6.3, 3.7, and 5.8 cm ·s , and the mean particle growth rate was 3.6, 6.0, and 6.2 nm·h at SDZ, TS, and LAN, respectively. The NPF event characteristics at the three sites indicate that there may be a stronger source of low volatile vapors and higher condensational sink of pre-existing particles in the YRD region. The formation rate of NPF events at these sites, as well as the condensation sink, is approximately 10 times higher than some results reported at rural/urban sites in western countries. However, the growth rates appear to be 1–2 times higher. Approximately 12%–17% of all NPF events with nucleated particles grow to a climate-relevant size (>50 nm). These kinds of NPF events were normally observed with higher growth rate than the other NPF cases. Generally, the cloud condensation nuclei (CCN) number concentration can be enhanced by approximately a factor of 2–6 on these event days. The mean value of the enhancement factor is lowest at LAN (2–3) and highest at SDZ (~4). NPF events have also been found to have greater impact on CCN production in China at the regional scale than in the other background sites worldwide.

关键词: New particle formation     Regional background     Cloud condensation nuclei     Growth rate     Formation rate    

CO capture and sequestration source-sink match optimization in Jing-Jin-Ji region of China

Zhong ZHENG , Dan GAO , Linwei MA , Zheng LI , Weidou NI ,

《能源前沿(英文)》 2009年 第3卷 第3期   页码 359-368 doi: 10.1007/s11708-009-0053-6

摘要: Carbon dioxide capture and sequestration (CCS) is considered to be an important option for climate change mitigation. A key problem for the implementation of CCS technology is the source-sink match design and optimization when considering both economic and environmental requirement. This paper presents a generic-optimization-based model for the strategic planning and design of future CCS source-sink matching. The features and capabilities of the model are illustrated through a detailed case study for the Jing-Jin-Ji (Beijing, Tianjin and Hebei Province) region in China. It shows how the model helps make a compromise in arriving at a strategic decision for CCS source-sink matching by providing the tradeoff frontiers between economic and environmental performance, and the features of match solutions with the best economic performance or with the best environmental performance.

关键词: CO2 capture and sequestration     China     source-sink match     tradeoff frontiers     multi-objective optimization    

Flow and thermal modeling of liquid metal in expanded microchannel heat sink

《能源前沿(英文)》   页码 796-810 doi: 10.1007/s11708-023-0877-5

摘要: Liquid metal-based microchannel heat sinks (MCHSs) suffer from the low heat capacity of coolant, resulting in an excessive temperature rise of coolant and heat sink when dealing with high-power heat dissipation. In this paper, it was found that expanded space at the top of fins could distribute the heat inside microchannels, reducing the temperature rise of coolant and heat sink. The orthogonal experiments revealed that expanding the top space of channels yielded similar temperature reductions to changing the channel width. The flow and thermal modeling of expanded microchannel heat sink (E-MCHS) were analyzed by both using the 3-dimensional (3D) numerical simulation and the 1-dimensional (1D) thermal resistance model. The fin efficiency of E-MCHS was derived to improve the accuracy of the 1D thermal resistance model. The heat conduction of liquid metal in Z direction and the heat convection between the top surface of fins and the liquid metal could reduce the total thermal resistance (Rt). The above process was effective for microchannels with low channel aspect ratio, low mean velocity (Um) or long heat sink length. The maximum thermal resistance reduction in the example of this paper reached 36.0%. The expanded space endowed the heat sink with lower pressure, which might further reduce the pumping power (P). This rule was feasible both when fins were truncated (h2 < 0, h2 is the height of expanded channel for E-MCHS) and when over plate was raised (h2 > 0).

关键词: liquid metal cooling     heat sink     expanded microchannel     flow and thermal modeling    

Review of the LNG intermediate fluid vaporizer and its heat transfer characteristics

《能源前沿(英文)》 2022年 第16卷 第3期   页码 429-444 doi: 10.1007/s11708-021-0747-y

摘要: The intermediate fluid vaporizer (IFV), different from other liquefied natural gas (LNG) vaporizers, has many advantages and has shown a great potential for future applications. In this present paper, studies of IFV and its heat transfer characteristics in the LNG vaporization unit E2 are systematically reviewed. The research methods involved include theoretical analysis, experimental investigation, numerical simulation, and process simulation. First, relevant studies on the overall calculation and system design of IFV are summarized, including the structural innovation design, the thermal calculation model, and the selection of different intermediate fluids. Moreover, studies on the fluid flow and heat transfer behaviors of the supercritical LNG inside the tubes and the condensation heat transfer of the intermediate fluid outside the tubes are summarized. In the thermal calculations of the IFV, the selections of the existing heat transfer correlations about the intermediate fluids are inconsistent in different studies, and there lacks the accuracy evaluation of those correlations or comparison with experimental data. Furthermore, corresponding experiments or numerical simulations on the cryogenic condensation heat transfer outside the tubes in the IFV need to be further improved, compared to those in the refrigeration and air-conditioning temperature range. Therefore, suggestions for further studies of IFV are provided as well.

关键词: intermediate fluid vaporizer     design of structure and intermediate fluid     condensation heat transfer    

我国典型农作区作物生产碳汇功能研究

佘玮,黄璜,官春云,陈阜,陈光辉

《中国工程科学》 2016年 第18卷 第1期   页码 106-113 doi: 10.15302/J-SSCAE-2016.01.013

摘要:

我国是一个农业大国,研究我国典型农作区作物生产碳汇对于估算区域碳收支和制定应对气候变化的管理政策有重要的意义。全国6个典型农作区中主要农作物生产整体表现为碳汇。同一区域内不同作物的碳汇量差异明显,同一作物在不同区域之间差异显著。全国年土壤有机碳储量整体表现为碳汇,不同区域年土壤有机碳储量的范围为–2.07 TgC·y–1~19.95 TgC·y–1。

关键词: 作物生产     固碳减排措施     碳汇功能    

Influence of infiltration on energy consumption of a winery building

Hejiang SUN, Qingxia YANG

《能源前沿(英文)》 2014年 第8卷 第1期   页码 110-118 doi: 10.1007/s11708-013-0293-3

摘要: With the wide use of light steel structure in industrial buildings, some problems such as air leakage, water dripping and condensation and so forth occur during the construction and operation phases. Through the onsite testing of a winery building in Huailai County, Hebei Province in China, the influence of infiltration on energy consumption in industrial buildings was studied. The pressurization test method and moisture condensation method were used to test the infiltration rates. The results show that the winery building is twice as leaky as normal Chinese buildings and five times as leaky as Canadian buildings. The energy use simulation demonstrates that the reduction of the infiltration rate of the exterior rooms to 1/3 and the interior rooms to 1/2 could help decrease a total energy consumption of approximately 20% and reduce a total energy cost of approximately $ 225000. Therefore, it has a great potential to reduce the energy consumption in this type of buildings. Enforcement of the appropriate design, construction and installation would play a significant role in improving the overall performance of the building.

关键词: industrial building     air change rate     pressurization test method     moisture condensation method     energy cost    

我国主要农作物生产碳汇结构现状与优化途径

佘玮,黄璜,官春云,陈阜,陈光辉

《中国工程科学》 2016年 第18卷 第1期   页码 114-122 doi: 10.15302/J-SSCAE-2016.01.014

摘要:

大气中温室气体浓度的增加引起的全球气候变化成为威胁人类生存和发展的一大难题。农作物的碳汇功能对气候变化也起着重要的调节作用。农作物的生产过程既是碳源也是碳汇。本文收集整理分析了我国主要农作物农作系统的相关碳排放参数,估算了农田碳汇碳源效应及其动态变化特征,对作物生产系统的碳投入产出进行定量评价。为我国发展低碳农业规划、政策制定提供了依据,并提出了我国农田碳汇结构的优化途径。

关键词: 农作物     碳汇     碳排放     优化途径    

土地利用变化对生态系统碳汇功能影响的综合评价

吴建国,张小全,徐德应

《中国工程科学》 2003年 第5卷 第9期   页码 65-71

摘要:

在分析了六盘山林区典型生态系统碳循环规律的基础上,结合碳汇/源的概念,综合评价了土地利用 变化对生态系统碳汇功能的影响。分析得出陆地生态系统碳汇/源功能体现在碳库的贮量、稳定性和碳库的输入 与输出强度方面;天然次生林和人工林生态系统的碳贮量汇功能较强,农田和草地较弱;土壤有机碳过程源/汇 方面,天然次生林生态系统是强汇,人工林生态系统是弱汇,草地和农田生态系统是源。提出增加生态系统碳 汇功能的措施包括增加生态系统碳输入、减少输出和增强碳库的稳定性。

关键词: 土地利用变化     土壤有机碳     碳循环     生态系统的碳汇/源    

High heat flux thermal management through liquid metal driven with electromagnetic induction pump

《能源前沿(英文)》 2022年 第16卷 第3期   页码 460-470 doi: 10.1007/s11708-022-0825-9

摘要: In this paper, a novel liquid metal-based minichannel heat dissipation method was developed for cooling electric devices with high heat flux. A high-performance electromagnetic induction pump driven by rotating permanent magnets is designed to achieve a pressure head of 160 kPa and a flow rate of 3.24 L/min, which could enable the liquid metal to remove the waste heat quickly. The liquid metal-based minichannel thermal management system was established and tested experimentally to investigate the pumping capacity and cooling performance. The results show that the liquid metal cooling system can dissipate heat flux up to 242 W/cm2 with keeping the temperature rise of the heat source below 50°C. It could remarkably enhance the cooling performance by increasing the rotating speed of permanent magnets. Moreover, thermal contact resistance has a critical importance for the heat dissipation capacity. The liquid metal thermal grease is introduced to efficiently reduce the thermal contact resistance (a decrease of about 7.77 × 10−3 °C/W). This paper provides a powerful cooling strategy for thermal management of electric devices with large heat power and high heat flux.

关键词: high heat flux     liquid metal     electromagnetic pump     minichannel heat sink     thermal interface material    

标题 作者 时间 类型 操作

Heat-spreading analysis of a heat sink base embedded with a heat pipe

B. V. BORGMEYER, H. B. MA,

期刊论文

海洋渔业碳汇及其扩增战略

唐启升,刘 慧

期刊论文

Effect of / molecular structures on pyrolysis performance and heat sink of decalin isomers

期刊论文

Effects of radiation and heat source/sink on unsteady MHD boundary layer flow and heat transfer over

Krishnendu Bhattacharyya

期刊论文

On secondary new particle formation in China

Markku Kulmala,Tuukka Petäjä,Veli-Matti Kerminen,Joni Kujansuu,Taina Ruuskanen,Aijun Ding,Wei Nie,Min Hu,Zhibin Wang,Zhijun Wu,Lin Wang,Douglas R. Worsnop

期刊论文

Development of a cloud condensation nuclei (CCN) counter using a laser and charge-coupled device (CCD

Mikyung PARK, Jinkwan OH, Kihong PARK

期刊论文

features of new particle formation events at background sites in China and their influence on cloud condensation

Xiaojing SHEN,Junying SUN,Xiaoye ZHANG,Yangmei ZHANG,Lu ZHANG,Ruxia FAN

期刊论文

CO capture and sequestration source-sink match optimization in Jing-Jin-Ji region of China

Zhong ZHENG , Dan GAO , Linwei MA , Zheng LI , Weidou NI ,

期刊论文

Flow and thermal modeling of liquid metal in expanded microchannel heat sink

期刊论文

Review of the LNG intermediate fluid vaporizer and its heat transfer characteristics

期刊论文

我国典型农作区作物生产碳汇功能研究

佘玮,黄璜,官春云,陈阜,陈光辉

期刊论文

Influence of infiltration on energy consumption of a winery building

Hejiang SUN, Qingxia YANG

期刊论文

我国主要农作物生产碳汇结构现状与优化途径

佘玮,黄璜,官春云,陈阜,陈光辉

期刊论文

土地利用变化对生态系统碳汇功能影响的综合评价

吴建国,张小全,徐德应

期刊论文

High heat flux thermal management through liquid metal driven with electromagnetic induction pump

期刊论文