检索结果-南通市图书馆

Influences of external heat transfer and Thomson effect on the performance of TEG-TEC combined thermoelectric device

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2018年第10期61卷 1600-1610页

作者： FENG yuanli CHEN LinGen MENG FanKai SUN FengRui Institute of Thermal Science and Power Engineering Naval University of Engineering Military Key Laboratory for Naval Ship Power Engineering Naval University of Engineering College of Power Engineering Naval University of Engineering

A thermodynamic model of a thermoelectric generator(TEG)-driven thermoelectric cooler(TEC) device considering Thomson effect and external heat transfer(HT) is established based on the combination of non-equilibrium and finite time thermodynamic theories. The expressions of cooling capacity and coefficient of performance(COP) are obtained. Performances are compared with and without considering Thomson effect using numerical optimization method. The influences of Thomson effect on the optimal performances, optimum allocations of thermoelectric(TE) element number and HT surface area are discussed. The results indicate that Thomson effect decreases the maximum cooling capacity and COP. More TE elements should be allocated to TEG, and more HT area should be allocated to the heat exchanger(HEX) of TEG, the hot-side HEX of TEG and the cold-side HEX of TEC in the design of the device considering Thomson effect. The results obtained can be used to help design TEG-TEC devices.

关键词： thermoelectric generator thermoelectric cooler combined thermoelectric device performance optimization non-equilibrium thermodynamics finite time thermodynamics

在线全文

学校读者我要写书评

暂无评论

助学教师如何指导学生制定个人学习计划

辽宁广播电视大学学报 2002年第3期 5-5页

作者：宋坤杨元利锦州电大

指导和帮助学生做好个人学习计划,是指导教师的一项重要工作。我们对此做了探索和实践,助学教师应帮助开放教育学生做好三个计划。

关键词：制定个人学习计划远程教育开放教育助学教师指导

在线全文

学校读者我要写书评

暂无评论

社区居民对大熊猫放归项目态度与预期行为

西华师范大学学报（自然科学版） 2017年第4期38卷 352-358,372页

作者：李程李玉杰董鑫张晋东白文科王晓杨远丽周材权西华师范大学生命科学学院四川南充637009 西华师范大学西南野生动植物资源保护教育部重点实验室四川南充637009 西华师范大学珍稀动植物研究所四川南充637009 西华师范大学环境科学与工程学院四川南充637009

珍稀野生物种的野化放归项目是否成功,与其栖息地生存周边的居民环境知识、态度和参与程度密切相关。正在进行的大熊猫野外放归项目是大熊猫保护的重要举措,目前主要针对圈养大熊猫的野化、放归地选择、放归大熊猫的野外跟踪开展一系列... 详细信息

珍稀野生物种的野化放归项目是否成功,与其栖息地生存周边的居民环境知识、态度和参与程度密切相关。正在进行的大熊猫野外放归项目是大熊猫保护的重要举措,目前主要针对圈养大熊猫的野化、放归地选择、放归大熊猫的野外跟踪开展一系列研究,而针对培训地、放归地的社区居民对放归项目的态度与行为响应尚未开展调查研究工作。作者运用远程耦合系统(2个及更多远距离区域之间的社会经济与环境交互作用)框架,研究了大熊猫培训地——卧龙保护区(发出系统),放归地——栗子坪保护区(接收系统)与潜在放归地——华蓥山(外溢系统)社区居民对大熊猫放归项目的态度、环境意识、参与程度与预期行为,比较各系统之间的差异性。结果表明:(1)总体上,各调查社区居民对大熊猫保护的重要性的认知程度相对较高(均高于85%),尤其在发出系统——卧龙保护区,作为大熊猫的著名保护区,受各界关注度较高,当地居民对大熊猫的认知程度相对更高。然而,每个调查社区居民对大熊猫相关知识的了解程度都较低,如对野外与圈养大熊猫数量的了解(均低于11%),这表明在放归项目执行过程中,在社区环境教育方面尚未开展深入工作;(2)尽管3个调查社区的居民多数都支持大熊猫放归野外,但是在实际的发出系统—卧龙与接收系统——栗子坪,对大熊猫放归的支持率明显低于外溢系统——华蓥山。这是因为在野化培训与放归过程中,尽管当地居民获得一些临时工作机会(如巡护员、维修护栏等),但管理部门对居民收集自然资源的行为进行更为严格的管控,如减少采药、打笋和放牧等,会在一定程度影响社区居民的经济来源。我们建议在放归大熊猫的同时也应考虑当地居民的利益,制定大熊猫保护与当地人福祉协调发展的政策。

关键词：大熊猫大熊猫放归项目远程耦合系统卧龙保护区栗子坪保护区华蓥山

Effect of Aspect Ratio on the Evolution of Shear Bands in Zr_(61.7)Al_8Ni_(13)Cu_(17)Sn_(0.3)Bulk Metallic Glass

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2017年第1期33卷 99-104页

作者： Wenli Ma yuanli Xu Bo Shi Jiangong Li Institute of Materials Science and Engineering and MOE Key Laboratory for Magnetism and Magnetic Materials Lanzhou UniversityLanzhou 730000China

Zr61.7A18Ni13Cu17Sn0.3 bulk metallic glass samples with different aspect ratios in the range of 0.25-2.25 were deformed by compression, and the effect of aspect ratio on the evolution of shear bands was investigated. It is found that for the deformed Zr61.7AlaNi13CulTSno3 bulk metallic glass, the average shear band spacing decreases and the shear band density increases monotonically as the aspect ratio increases from 0.25 to 2.25. A minimal average shear band spacing of 0.478μm is achieved for the sample with an aspect ratio of 2.25. In addition, the fractions of shear bands with spacings below 100 and 50 nm are about 12.84% and 6.76%, respectively, for the sample with an aspect ratio of 2.25. The reason for the formation of a higher density of shear bands can probably be attributed to the increase of the driving force for the samole with a larger aspect ratio.

关键词： Metallic glass Aspect ratio Shear band Compressive deformation

Distributions of dissolved oxygen and apparent oxygen utilization in the Cosmonaut Sea and Amundsen Sea in austral summer 2021

在线全文

学校读者我要写书评

暂无评论

Advances in Polar Science 2023年第4期34卷 272-303页

作者： GUO Jiaying yang Xufeng ZHAO Jun ZHU yuanli LI Dong PAN Jianming Key Laboratory of Marine Ecosystem Dynamics Ministry of Natural ResourcesHangzhou 310012China Second Institute of Oceanography Ministry of Natural ResourcesHangzhou 310012China

Dissolved oxygen(DO)and apparent oxygen utilization(AOU)are crucial parameters for investigating marine ecosystem evolution and the marine *** this study,DO and AOU data were obtained and their spatial distribution characteristics were explored in the Cosmonaut Sea and Amundsen Sea in austral summer *** standard deviation range of DO parallel samples was160μmol·L–1)could surge up to ca.150–200 m in both seas,with stronger intrusion in the Amundsen *** AOU in bottom water was significantly lower(p<0.01)in the Cosmonaut Sea(118.9±11.8μmol·L–1)than the Amundsen Sea(141.7±7.4μmol·L–1),indicating the stable existence of fresh oxygen-rich Antarctic Bottom Water in the Cosmonaut Sea.

关键词： dissolved oxygen apparent oxygen utilization Antarctic Cosmonaut Sea Amundsen Sea

Design of heat exchanger network based on entransy theory

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2018年第8期26卷 1692-1699页

作者： Li Xia yuanli Feng Xiaoyan Sun Shuguang Xiang Institute of Process System Engineering Ojngdao University of Sdence and Technology Qingdao 266042China

The heat exchanger network(HEN) synthesis problem based on entransy theory is analyzed. According to the characteristics of entransy representation of thermal potential energy, the entransy dissipation represents the irreversibility of the heat transfer process, the temperature difference determines the entransy dissipation, and four HEN design steps based on entransy theory are put forward. The present study shows how it is possible to set energy targets based on entransy and achieve them with a network of heat exchangers by an example of heat exchanger network design for four streams. In order to verify the correctness of the heat exchanger networks design method based on entransy theory, the synthesis of the HEN for the diesel hydrogenation unit is studied. Using the heat exchange networks design method based on entransy theory, the HEN obtained is consistent with energy targets. The entransy transfer efficiency of HEN based on entransy theory is 92.29%, higher than the entransy transfer efficiency of the maximum heat recovery network based on pinch technology.

关键词： Process systems Heat exchanger network synthesis Heat transfer Entransy Energy target Pinch

EXPRESSION OF mRNA FOR MEMBRANE-TYPE 1, 2, AND 3 MATRIX METALLOPROTEINASES IN HUMAN LARYNGEAL CANCER

在线全文

学校读者我要写书评

暂无评论

Chinese Medical Sciences Journal 2004年第3期19卷 170-173页

作者： Ya-nanSun yuanli DepartmentofEars NoseandThroattheThirdAffiliatedHospitalofSunYat-senUniversityGuangzhou510630

To investigate correlation of expressions of membrane-type 1, 2, and 3 matrix metalloproteinases (MT1, MT2, and MT3-MMP) to the invasion and metastases in laryngeal cancer. Methods Reverse transcription-polymerase chain reaction (RT-PCR) was used to examine the mRNA level of MT1, MT2, and MT3-MMP in 24 patients with laryngeal cancer. The relationships of these three MT-MMP expressions to clinico-pathology were analyzed by statistics. Results The expressions of MT1, MT2, and MT3-MMP were significantly higher in laryngeal cancer tissues than those in para-tumorous tissues (P 0.05). The expression of MT1-MMP was obviously higher in patients with metastatic lymph nodes than that in patients without metastatic lymph nodes (P < 0.05). Conclusion MT1, MT2, and MT3-MMP play an important role in the progression of laryngeal cancer, and MT1-MMP may serve as a reliable marker in estimating invasive and metastatic potency of laryngeal cancer. Suppressing expressions of MT1, MT2, and MT3-MMP early may inhibit the invasion and metastases of laryngeal cancer.

关键词： laryngeal cancer membrane type matrix metalloproteinases polymerase chain reaction

Online support vector regression for reinforcement learning

在线全文

学校读者我要写书评

暂无评论

High Technology Letters 2007年第2期13卷 173-176页

作者：于振华 Cai yuanli School of Electronic and Information Engineering Xi＇an Jiaotong University Xi＇an 710049 P.R.China

The goal in reinforcement learning is to learn the value of state-action pair in order to maximize the total reward. For continuous states and actions in the real world, the representation of value functions is critical. Furthermore, the samples in value functions are sequentially obtained. Therefore, an online sup-port vector regression （OSVR） is set up, which is a function approximator to estimate value functions in reinforcement learning. OSVR updates the regression function by analyzing the possible variation of sup-port vector sets after new samples are inserted to the training set. To evaluate the OSVR learning ability, it is applied to the mountain-car task. The simulation results indicate that the OSVR has a preferable con- vergence speed and can solve continuous problems that are infeasible using lookup table.

关键词： reinforcement learning function approximation support vector regression online leaming

Analysis on fluid permeability of dendritic mushy zone during peritectic solidification in a temperature gradient

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2021年第12期71卷 169-176页

作者： Peng Peng Jinmian Yue Anqiao Zhang Xudong Zhang yuanli Xu Institute of Materials Science and Engineering Lanzhou UniversityLanzhou730000China School of Physical Science and Technology Lanzhou UniversityLanzhou730000China

Compared with the growing applications of peritectic alloys,none research on the fluid permeability K of dendritic network during peritectic solidification has been reported *** fluid permeability K of dendritic network in the mushy zone during directional solidification of Sn-Ni peritectic alloy was investigated in this *** on the experimental results demonstrates that both the temperature gradient zone melting(TGZM)and Gibbs-Thomson(G–T)effects have obvious influences on the morphology of dendritic network during directional *** is realized through different stages of liquid diffusion within dendritic mushy zone by these effects during directional *** TGZM effect is demonstrated to play a more important role as compared with the G–T effect during directional ***,it is shown that the evolution of dendrite network is more complex during peritectic solidification due to the involvement of the peritectic *** the specific surface SV,analytical expression based on the Carman–Kozeny model was proposed to analyze the fluid permeability of dendritic mushy zone in directionally solidified peritectic *** addition,it is interesting to find a rise in permeability K after peritectic reaction in both theoretical predication and experimental results,which is different from that in other *** theoretical predictions show that this rise in fluid permeability K after peritectic reaction is caused by the remelting/resolidification process on dendritic structure by the TGZM and G–T effects during peritectic solidification.

关键词： Alloys Diffusion behaviour Directional solidification Peritecticm icrostructures Solid/liquid interface