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THE HILBERT BOUNDARY VALUE PROBLEM FOR GENERALIZED ANALYTIC FUNCTIONS IN CLIFFORD ANALYSIS 被引量:2
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作者 司中伟 杜金元 《Acta Mathematica Scientia》 SCIE CSCD 2013年第2期393-403,共11页
Let R0,n be the real Clifford algebra generated by e1, e2,... , en satisfying eiej+ejei=-2δij,i,j=1,2…,ne0 is the unit element.Let Ω be an open set. A function f is called left generalized analytic in ft if f sati... Let R0,n be the real Clifford algebra generated by e1, e2,... , en satisfying eiej+ejei=-2δij,i,j=1,2…,ne0 is the unit element.Let Ω be an open set. A function f is called left generalized analytic in ft if f satisfies the equation Lf=0,where ……qi 〉0, i =-, 1, - ……, n. In this article, we first give the kernel function for the generalized analytic function. Further, the Hilbert boundary value problem for generalized analytic functions in Rn+1 will be investigated. 展开更多
关键词 Generalized analytic function Hilbert boundary value problem H^u function
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Assessment of ecosystem services value in response to prevailing and future land use/cover changes in Lahore,Pakistan 被引量:2
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作者 Mobeen Akhtar Yuanyuan Zhao +3 位作者 Guanglei Gao Qudsia Gulzar Azfar Hussain Abdus Samie 《Regional Sustainability》 2020年第1期37-47,共11页
Land use/cover changes(LUCCs)significantly affect ecosystem services(ESs)and their corresponding monetary value.ESs can be evaluated to analyze the ecological and environmental changes caused by LUCCs.This research ai... Land use/cover changes(LUCCs)significantly affect ecosystem services(ESs)and their corresponding monetary value.ESs can be evaluated to analyze the ecological and environmental changes caused by LUCCs.This research aims to estimate variations in the ecosystem services value(ESV)due to LUCCs in Lahore of Pakistan,and to offer information and recommendations to policy-makers concerned with the economic improvement of metropolis areas.We first investigated the historical LUCCs from 1990 to 2019,and then simulated the future land use/cover in 2030 and 2050 based on the CA-Markov model under three scenarios,including business-as-usual(BAU),rapid economic growth(REG),and coordinated environmental sustainability(CES).Subsequently,we evaluated the ESV from 1990 to 2050 and evaluated the historical and potential future ESV changes induced by LUCCs during 1990–2019 and 2019–2050,respectively.The results showed that,land use/cover exhibited an increase in built-up land and decreases in vegetation,water body,and unused land both in the past and future.The net ESV decreased from 58.26 million USD in 1990 to 50.31 million USD in 2019.In 2050,the decrease in ESV is most rapid under the REG scenario(decrease ESV of 7.13 million USD and decrease percentage of 14.18%),followed by the BAU(decrease ESV of 5.61 million USD and decrease percentage of 11.15%)and CES(decrease ESV of 5.18 million USD and decrease percentage of 10.30%)scenarios.For each ecosystem service type,the ESV of waste treatment decreased by 18.37%from 1990 to 2019,followed by soil formation and conservation(17.52%),biodiversity and maintenance(13.23%),climate regulation(11.80%),food production(11.69%),hydrological regulation(11.11%),and aesthetic value(3.07%).These outcomes indicate that continuous land use/cover planning should focus on regenerating aquatic areas and vegetation restoration. 展开更多
关键词 Ecosystem services Land use/cover changes Environmental sustainability ca Markov urban expansion value coefficient
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Non Intrusive U Value Metering
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作者 Nikos Sakkas Jaume Madrid Valls +1 位作者 Costas Daskalakis Evangelos Kaltsis 《Open Journal of Energy Efficiency》 2015年第2期28-35,共8页
The significance of U values in buildings’ shell energy performance is well known in the scientific community as well as in the construction sector. In addition, conducting a validation of the energy performance of a... The significance of U values in buildings’ shell energy performance is well known in the scientific community as well as in the construction sector. In addition, conducting a validation of the energy performance of a building often requires the knowledge of real U value figures, since their theoretical peers may deviate considerably from the real ones. The theoretical U value of a shell element may be calculated using complex material and surface related information, while its practical validation is conducted usually by equipment that requires tedious installation and constant contact with the examined element. Aim of this paper is to introduce an easily deployed, plug and play, contact less technology, able to provide a reasonable approximation of the building element U value and its variation with external air speed as well as an accurate estimation of the U value change in case of a shell (wall or window) retrofit. 展开更多
关键词 u value METERING RETROFIT Impact on u value Plug and PLAY and Non-Intrusive METERING IR Sensing Wireless Sensor Networks—WSN
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Absolute Reference Values of the Real Gas
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作者 Albrecht Elsner 《Engineering(科研)》 2018年第5期270-290,共21页
With his publication in 1873 [1] J. W. Gibbs formulated the thermodynamic theory. It describes almost all macroscopically observed properties of matter and could also describe all phenomena if only the free energy U -... With his publication in 1873 [1] J. W. Gibbs formulated the thermodynamic theory. It describes almost all macroscopically observed properties of matter and could also describe all phenomena if only the free energy U - ST were explicitly known numerically. The thermodynamic uniqueness of the free energy obviously depends on that of the internal energy U and the entropy S, which in both cases Gibbs had been unable to specify. This uncertainty, lasting more than 100 years, was not eliminated either by Nernst’s hypothesis S = 0 at T = 0. This was not achieved till the advent of additional proof of the thermodynamic relation U = 0 at T = Tc. It is noteworthy that from purely thermodynamic consideration of intensive and extensive quantities it is possible to derive both Gibbs’s formulations of entropy and internal energy and their now established absolute reference values. Further proofs of the vanishing value of the internal energy at the critical point emanate from the fact that in the case of the saturated fluid both the internal energy and its phase-specific components can be represented as functions of the evaporation energy. Combining the differential expressions in Gibbs’s equation for the internal energy, d(μ/T)/d(1/T) and d(p/T)/d(1/T), to a new variable d(μ/T)/d(p/T) leads to a volume equation with the lower limit vc as boundary condition. By means of a variable transformation one obtains a functional equation for the sum of two dimensionless variables, each of them being related to an identical form of local interaction forces between fluid particles, but the different particle densities in the vapor and liquid spaces produce different interaction effects. The same functional equation also appears in another context relating to the internal energy. The solution of this equation can be given in analytic form and has been published [2] [3]. Using the solutions emerging in different sets of problems, one can calculate absolutely the internal energy as a function of temperature-dependent, phase-specific volumes and vapor pressure. 展开更多
关键词 ENTROPY REFERENCE value S (M V 0) = 0 INTERNAL Energy REFERENCE value u (M Tc) = 0 ...
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Loan Loss Reserves (LLR), Expected Loss (EL), and Value at Risks (VaR)
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作者 Mohd Yaziz Mohd Isa Yap Voon Choong +1 位作者 David Yong Gun Fie Md. Zabid Hj. Abdul Rashid 《Journal of Modern Accounting and Auditing》 2015年第4期218-222,共5页
关键词 准备金 LLR 损失 贷款 EL VAR 风险 商业银行
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川东北石笋SI3的U/Ca值变化及其古气候意义 被引量:1
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作者 陈琳 黄嘉仪 +6 位作者 刘淑华 陈琼 杨亮 贺海波 米小建 杨琰 周厚云 《矿物岩石地球化学通报》 CAS CSCD 北大核心 2016年第1期183-187,共5页
为探讨洞穴次生碳酸盐沉积U元素含量变化的气候环境意义,以川东北狮子洞石笋SI3为研究对象,通过对SI3的U/Ca值进行分析,发现在53.2~45.8ka之间SI3的U/Ca值变化与该石笋和格陵兰冰心NGRIP的δ^(18)O记录具有良好的对应关系。U/Ca值在东... 为探讨洞穴次生碳酸盐沉积U元素含量变化的气候环境意义,以川东北狮子洞石笋SI3为研究对象,通过对SI3的U/Ca值进行分析,发现在53.2~45.8ka之间SI3的U/Ca值变化与该石笋和格陵兰冰心NGRIP的δ^(18)O记录具有良好的对应关系。U/Ca值在东亚夏季风减弱时期偏大,在夏季风增强时期偏小。此外U/Ca值很好地记录了H5冷事件和GIS12、GIS13及GIS14暖事件。 展开更多
关键词 石笋 u/ca 夏季风 华中
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珊瑚中微量铀的ID-ICP-MS高精度测定及其在珊瑚U/Ca温度计研究中的应用 被引量:7
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作者 韦刚健 李献华 +1 位作者 刘海臣 孙敏 《地球化学》 CAS CSCD 北大核心 1998年第2期125-131,共7页
建立了同位素稀释技术与ICP-MS相结合的ID-ICP-MS分析方法,成功测量了取自南海北部的滨珊瑚样品中的微量铀,获得0.5%左右的精度。并以此建立南海北部近岸海域的珊瑚U/Ca温度计,其温度精度可达±0.5℃。
关键词 ID-ICP-MS 珊瑚 铀/钙温度计
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偕胺肟水热碳对U(Ⅵ)-CO3/Ca-U(Ⅵ)-CO3的吸附性能研究 被引量:1
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作者 张志宾 周润泽 +2 位作者 董志敏 曹小红 刘云海 《无机材料学报》 SCIE EI CAS CSCD 北大核心 2020年第3期352-358,共7页
水热碳吸附材料具有制备工艺简单、合成条件温和、表面易改性等优点。本研究以可溶性淀粉为碳源,在硝酸铈铵催化作用下,将丙烯腈开环接枝到淀粉分子上,通过水热反应和盐酸羟胺还原制备偕胺肟化水热碳(AO-HTC)。结合静态和动态吸附实验,... 水热碳吸附材料具有制备工艺简单、合成条件温和、表面易改性等优点。本研究以可溶性淀粉为碳源,在硝酸铈铵催化作用下,将丙烯腈开环接枝到淀粉分子上,通过水热反应和盐酸羟胺还原制备偕胺肟化水热碳(AO-HTC)。结合静态和动态吸附实验,重点研究了溶液pH、碳酸根和钙离子浓度对AO-HTC吸附铀性能的影响,通过Thomas和Yoon-Nelson模型探究AO-HTC吸附铀的动态过程。结果表明:随着pH、碳酸根浓度和钙浓度的增加,AO-HTC吸附铀的容量逐渐降低;掺杂5wt%AO-HTC土壤柱的穿透点和饱和点体积也随之减小。与纯土壤柱相比,掺杂5wt%AO-HTC土壤柱的最大吸附容量(qo)和吸附质穿透50%所需的时间(τ)增大了数倍。由此可见,AO-HTC是一种性能优异的可渗透性反应墙(PRB)介质,有望用于修复铀污染土壤和地下水。 展开更多
关键词 偕胺肟基 水热碳 u(Ⅵ)-CO3/ca-u(Ⅵ)-CO3 吸附
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棉花U3和U6启动子在CRISPR/Cas9基因组编辑体系中的功能鉴定 被引量:2
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作者 藏旭阳 代培红 +3 位作者 李继洋 蒲艳 顾爱星 刘晓东 《棉花学报》 CSCD 北大核心 2019年第1期31-39,共9页
【目的】对已克隆的海岛棉U3和U6启动子进行功能鉴定,为构建棉花CRISPR/Cas9多位点基因编辑技术体系提供更多可用的U3和U6启动子。【方法】分别构建以GbU3-2P和GbU6-7P为启动子驱动sg RNA,以抗旱负调控基因GGB为靶序列的CRISPR/Cas9基... 【目的】对已克隆的海岛棉U3和U6启动子进行功能鉴定,为构建棉花CRISPR/Cas9多位点基因编辑技术体系提供更多可用的U3和U6启动子。【方法】分别构建以GbU3-2P和GbU6-7P为启动子驱动sg RNA,以抗旱负调控基因GGB为靶序列的CRISPR/Cas9基因编辑载体,然后在新海16的棉花叶片原生质体中进行功能鉴定。通过Polymerase chain reaction方法富集构建好的CRISPR/Cas9基因编辑载体的核心片段,并利用PEG瞬时转化法将核心片段转入原生质体中。提取转化后的原生质体基因组DNA,采用酶切/Polymerase chain reaction法分析棉花GGB基因的突变情况并测序验证。最后绘制靶基因突变的频率分布图来计算该CRISPR/Cas9系统的编辑效率和确认突变的真实性。【结果】靶基因测序结果显示靶标位点序列突变的类型全部为碱基替换。【结论】以GbU3-2P和GbU6-7P为启动子的CRISPR/Cas9基因编辑体系可以成功地定点编辑棉花GGB基因的序列,引起基因突变。 展开更多
关键词 棉花 CRISPR/cas9 基因组编辑 u3/u6启动子 原生质体
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一种海岛棉U6启动子在CRISPR/Cas9基因组编辑体系中的功能鉴定 被引量:2
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作者 藏旭阳 代培红 +3 位作者 李继洋 蒲艳 刘晓东 顾爱星 《新疆农业大学学报》 CAS 2018年第1期31-35,共5页
U6启动子是CRISPR/Cas9基因编辑系统的重要元件之一。本研究以实验室已克隆的海岛棉U6启动子构建GbU6-1P启动子驱动sgRNA,构建以抗旱负调控基因GGB为靶序列的CRISPR/Cas9基因编辑载体,转入棉花‘新海16号’原生质体中,进行功能鉴定。经... U6启动子是CRISPR/Cas9基因编辑系统的重要元件之一。本研究以实验室已克隆的海岛棉U6启动子构建GbU6-1P启动子驱动sgRNA,构建以抗旱负调控基因GGB为靶序列的CRISPR/Cas9基因编辑载体,转入棉花‘新海16号’原生质体中,进行功能鉴定。经酶切实验验证、测序、数据统计等确认GbU6-1P启动子在基因编辑系统中的效果。结果表明,以GbU6-1P启动子构建的CRISPR/Cas9基因编辑体系可以成功地定点编辑棉花内源靶基因GGB,引起基因突变,突变率为34.5%,突变类型全部为碱基替换。 展开更多
关键词 棉花 CRISPR/cas9 基因组编辑 u6启动子 原生质体
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Relationship between serum calcium and CA 19-9 levels in colorectal cancer 被引量:5
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作者 PeterFuszek PeterLakatos +6 位作者 AdamTabak JanosPapp ZsoltNagy IstvanTakacs HenrikCsabaHorvath PeterLaszloLakatos GaborSpeer 《World Journal of Gastroenterology》 SCIE CAS CSCD 2004年第13期1890-1892,共3页
AIM: To examine the calcium metabolism of colorectal cancer (CRC) in patients with colorectal cancer and control patients.METHODS: Seventy newly diagnosed CRC patients were included. The healthy control group was age ... AIM: To examine the calcium metabolism of colorectal cancer (CRC) in patients with colorectal cancer and control patients.METHODS: Seventy newly diagnosed CRC patients were included. The healthy control group was age and gender matched (n=32). Particular attention was devoted to the relationship between serum calcium of patients, and levels of AFP, CEA, carbohydrate antigen 19-9 (CA 19-9) (that could be considered as prognostic factors). Furthermore, the Ca-sensing receptor (CaSR) gene A986S polymorphism was investigated in these patients, as well as the relationship between different CaSR genotypes and the data stated above.RESULTS: A lower level of ionized calcium (also corrected for albumin) was found in the serum of CRC patients with normal 25(0H) vitamin D levels. The ionized calcium concentration was inversely correlated with the serum level of CA 19-9. There was no difference in the distribution of CaSR genotypes, between CRC patients and general population. The genotypes did not correlate with other data examined.CONCLUSION: Based on these results, lower levels of serum calcium might be a pathogenic and prognostic factor in colorectal cancer. 展开更多
关键词 免疫血清 钙元素 ca 19-9 结直肠癌 肿瘤
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U形宽河谷典型拱坝坝体抗剪安全分析研究
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作者 王大威 王昱 刘国华 《水力发电》 CAS 2023年第4期47-54,80,共9页
我国缺少合理的拱坝坝体抗剪安全控制准则。由于实际工程地形地质条件不一,难以对比分析,故参照实际工程自拟坝高、河谷条件不同的U形宽河谷典型拱坝,模拟坝体超载破坏,对比超载安全度。结果表明,坝高越高、宽高比越大、河谷越偏于U形,... 我国缺少合理的拱坝坝体抗剪安全控制准则。由于实际工程地形地质条件不一,难以对比分析,故参照实际工程自拟坝高、河谷条件不同的U形宽河谷典型拱坝,模拟坝体超载破坏,对比超载安全度。结果表明,坝高越高、宽高比越大、河谷越偏于U形,考虑剪切破坏的超载安全度就越低。考虑横缝、施工层面、开裂面强度折减后,部分案例超载安全度低于现行规范基于拉压强度控制的期望值。建立截面抗剪安全系数与规范期望安全度的关联,得出针对不同坝高、河谷条件的坝体拱/梁截面抗剪安全系数控制值。检验坡甲、白莲崖两座拱坝,坡甲未达到抗剪安全控制值要求,白莲崖满足要求,结论与工程经验判断相符。 展开更多
关键词 拱坝坝体 u形宽河谷 剪切破坏 超载安全度 控制值
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CAS-KIT液压提升法与冲顶提升法在上颌窦内提升术中的应用观察
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作者 张凤成 魏泽宁 李丹 《中华老年口腔医学杂志》 2023年第5期285-288,共4页
目的探讨CAS-KIT液压提升法与冲顶提升法(骨凿法)在上颌窦内提升术中的应用效果。方法收集上颌窦内提升并同期完成种植的58例患者,其中30例采用CAS-KIT液压提升法,28例采用冲顶提升法,比较两组术后骨高度及骨提升幅度,记录黏膜穿孔数、... 目的探讨CAS-KIT液压提升法与冲顶提升法(骨凿法)在上颌窦内提升术中的应用效果。方法收集上颌窦内提升并同期完成种植的58例患者,其中30例采用CAS-KIT液压提升法,28例采用冲顶提升法,比较两组术后骨高度及骨提升幅度,记录黏膜穿孔数、感染数、植体脱落数、修复前ISQ值等指标,进行统计学分析。结果CAS-KIT液压提升组术后骨高度及骨提升幅度大于冲顶提升组(P<0.05);两组黏膜穿孔率、术后感染、修复前ISQ值、植体脱落率、总并发症率等方面无统计学差异(P>0.05)。结论CAS-KIT液压提升法和冲顶提升法均可以取得较好的临床效果,而前者在骨提升幅度方面更具优势,且能降低患者术中的不适感,预期性较好。 展开更多
关键词 caS-KIT液压提升法 冲顶提升法 上颌窦内提升 ISQ值
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Uranium Metabolism Associated with Ontogenetic Growth of Birds—Case Studies with Broilers and Ducks
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作者 Joao Dias de Toledo Arruda-Neto Guacyara Tenorio Cavalcante +4 位作者 Guilherme de Paula Nogueira Tulio Eduardo Rodrigues Luiz Eduardo Correa Fonseca Mitiko Saiki Godofredo Camara Genofre 《Advances in Bioscience and Biotechnology》 2014年第9期768-776,共9页
Cobb broilers and domestic ducks, both one-day-old, were treated using ration doped with 20 ppm of uranyl nitrate. Uranium concentrations in the tibia (μg-U/g-bone) were measured by neutron activation analysis as fun... Cobb broilers and domestic ducks, both one-day-old, were treated using ration doped with 20 ppm of uranyl nitrate. Uranium concentrations in the tibia (μg-U/g-bone) were measured by neutron activation analysis as function of the animals’ age, from the neonatal period to maturity. Results show that Uranium and Calcium qualitatively follow the same metabolic pathway, and that adult ducks incorporate on average ten times more Uranium than broilers. Data interpretation shows that the Uranium clearance rate in broilers is substantially higher than that in ducks, suggesting that metabolic characteristics favoring Calcium retention in bone may hinder the elimination of Uranium in ducks. The need for further comparative biochemistry studies between Galliformes and Anseriformes is addressed. 展开更多
关键词 Cobb Broilers Domestic Ducks uranium-Doped-Ration uranium-Content in Bones u/ca Metabolism uranium Residence Times
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CAS Scientist Engaged as Chancellor of a U.K. University
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《Bulletin of the Chinese Academy of Sciences》 2001年第1期12-13,共2页
Prof. Yang Fujia, a nuclearphysicist and educator, hasbeen elected as the Chancel-lor of the University of Nottingham,in the U.K. the first Chinese scholarto hold such a position in a Britishacademic institution, acco... Prof. Yang Fujia, a nuclearphysicist and educator, hasbeen elected as the Chancel-lor of the University of Nottingham,in the U.K. the first Chinese scholarto hold such a position in a Britishacademic institution, according tothe University’s public affairs office. "I feel privileged," said Prof.Yang. "And it is also an honor 展开更多
关键词 caS Scientist Engaged as Chancellor of a u.K uNIVERSITY
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精致美学工艺 华硕U305CA高性能运算体验
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《中国信息技术教育》 2016年第8期91-91,共1页
楔形流线设计在指尖上玩转应用作为13.3英寸笔记本电脑中轻盈度的佼佼者,华硕Zen Book U305CA整机采用楔形流线设计,融合钻石切割工艺,机身上盖采用同心圆拉发丝纹工艺,同时配合全铝合金的外观设计。华硕Zen Book U305CA支持高速响应触... 楔形流线设计在指尖上玩转应用作为13.3英寸笔记本电脑中轻盈度的佼佼者,华硕Zen Book U305CA整机采用楔形流线设计,融合钻石切割工艺,机身上盖采用同心圆拉发丝纹工艺,同时配合全铝合金的外观设计。华硕Zen Book U305CA支持高速响应触控屏,配合全新Windows8.1操作系统。 展开更多
关键词 u305ca 发丝纹 楔形 外观设计 笔记本电脑 流线设计 全铝合金 噪声抑制 动态范围 续航能力
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铁磁性及Hubbard U值对黄铜矿密度泛函理论计算的影响
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作者 李玉琼 简胜 陈建华 《矿产保护与利用》 2023年第1期32-36,共5页
黄铜矿具有反铁磁性,在密度泛函理论(DFT)计算过程中,磁性设置对计算的准确性非常重要,另外Hubbard U值对具有电子强关联性的Fe 3d轨道的修正对获得正确的电子结构也至关重要。研究了铁磁性、反铁磁性和Hubbard U值修正对黄铜矿密度泛... 黄铜矿具有反铁磁性,在密度泛函理论(DFT)计算过程中,磁性设置对计算的准确性非常重要,另外Hubbard U值对具有电子强关联性的Fe 3d轨道的修正对获得正确的电子结构也至关重要。研究了铁磁性、反铁磁性和Hubbard U值修正对黄铜矿密度泛函理论计算结果的影响。结果表明,没有设置U值修正会导致晶格常数偏离实验值较远,只有在反铁磁性和2.0eV的U值同时设置条件下,黄铜矿的晶格参数与带隙值才非常接近实验值。无任何磁性设置时,表面结构弛豫变化较大,并且捕收剂乙基硫氨酯(Z-200)不能吸附;铁磁性设置对Cu的结构弛豫影响大于Fe的结构弛豫,反铁磁性设置对这两种金属元素的弛豫影响相同,都使其在表面上与S成键后呈近似平面的结构;另外,Z-200在铁磁性表面的吸附弱于在反铁磁性表面的吸附。研究表明反铁磁性设置和Hubbard U修正对黄铜矿的密度泛函理论计算非常重要,该研究为黄铜矿的密度泛函理论计算提供了参考。 展开更多
关键词 黄铜矿 密度泛函理论计算 反铁磁性 Hubbard u
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多型腔U形扣注射模浇口排列布置与禁忌
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作者 高俊丽 袁开波 文根保 《模具制造》 2023年第1期28-32,35,共6页
U形扣注射模结构设计并不算复杂,由于该注射模结构对于多型腔排列布置没有规避浇注系统的禁忌,造成成型的三分之二的U形扣产生了填充不足和缩痕等缺陷。对于多型腔分流道长度不等的型腔排列,是需要反复计算浇口的平衡值,通过改变浇口截... U形扣注射模结构设计并不算复杂,由于该注射模结构对于多型腔排列布置没有规避浇注系统的禁忌,造成成型的三分之二的U形扣产生了填充不足和缩痕等缺陷。对于多型腔分流道长度不等的型腔排列,是需要反复计算浇口的平衡值,通过改变浇口截面和浇口长度的计算,并以计算数据为依据进行反复的浇口修理,以便达到塑料熔体流量的平衡,但这样做是得不偿失的。该案例就是一种警示,对于多型腔注射模的排列布置,一定要注意浇口截面的平衡值的计算。若在制订模具结构方案就注意到多型腔的排列布置浇口的平衡性,采用了等分流道长度的排列布置,就能完全避免浇注系统布置的禁忌。 展开更多
关键词 u形扣 多型腔 排列布置 平衡值 禁忌
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“华龙一号”核电厂倒U形预应力钢束摩擦力试验研究
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作者 曹钟引 陈伟 《中国核电》 2023年第6期798-804,共7页
“华龙一号”作为完全自主知识产权当代核电技术,其内层安全壳采用了倒U+水平预应力布置的预应力混凝土结构,在预应力正式施工前为了测试预应力孔道的摩擦力系数与设计数值的吻合度,需要选定特定的钢束通过千斤顶进行逐级拉伸测试其伸... “华龙一号”作为完全自主知识产权当代核电技术,其内层安全壳采用了倒U+水平预应力布置的预应力混凝土结构,在预应力正式施工前为了测试预应力孔道的摩擦力系数与设计数值的吻合度,需要选定特定的钢束通过千斤顶进行逐级拉伸测试其伸长值、拉力值,通过计算得出实际的摩擦系数。设计人员根据试验结果与理论数值的对比,验证和判断预应力孔道的成孔效果,并以此判断是否需要调整设计摩擦系数、张拉力和伸长值等理论数据。作为首堆工程,针对“华龙一号”核电厂倒U形钢束的摩擦力试验结果具有很好代表性和指导性。 展开更多
关键词 “华龙一号” 预应力 摩擦力试验 u形钢束 伸长值
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基于CA的城市增长与土地增值动态模拟方法探讨 被引量:42
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作者 韩玲玲 何政伟 +1 位作者 唐菊兴 李少达 《地理与地理信息科学》 CSSCI CSCD 北大核心 2003年第2期32-35,共4页
城市增长与土地增值是一种时空动态变化的复杂地理过程,如何有效地模拟这一过程是该研究领域的一个重要问题。基于GIS的元胞自动机模型,具有模拟地理时空演化过程的能力。该文首先对CA模型进行扩展,再与GIS集成,提出一种模拟城市增长与... 城市增长与土地增值是一种时空动态变化的复杂地理过程,如何有效地模拟这一过程是该研究领域的一个重要问题。基于GIS的元胞自动机模型,具有模拟地理时空演化过程的能力。该文首先对CA模型进行扩展,再与GIS集成,提出一种模拟城市增长与土地增值时空动态过程的新方法,并以四川省德阳市为例进行分析。 展开更多
关键词 城市增长 土地增值 元胞自动机模型 地理信息系统
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