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粉煤灰制备单相态分子筛及对溶液中Cu^(2+)的吸附 被引量:7
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作者 孙霞 黄丽平 +1 位作者 钱小军 李健生 《化工环保》 CAS CSCD 北大核心 2010年第6期539-543,共5页
以粉煤灰为原料,采用两步水热合成法制备分子筛。对所制备的分子筛的晶体类型和形貌进行表征,研究了所制备分子筛对溶液中Cu^(2+)的吸附性能。实验结果表明:控制硅铝凝胶中的m(SiO_2):m(Al_2O_3)分别为1.7和2.9,可得到单相态NaA型分子筛... 以粉煤灰为原料,采用两步水热合成法制备分子筛。对所制备的分子筛的晶体类型和形貌进行表征,研究了所制备分子筛对溶液中Cu^(2+)的吸附性能。实验结果表明:控制硅铝凝胶中的m(SiO_2):m(Al_2O_3)分别为1.7和2.9,可得到单相态NaA型分子筛和X型分子筛;硅铝凝胶在100℃的低温条件下晶化,有利于制备小粒径的NaA型分子筛;NaA型分子筛对Cu^(2+)的吸附容量大于X型分子筛;在25℃、溶液初始pH为3、Cu^(2+)质量浓度为50 mg/L、溶液体积为100 mL的条件下,NaA型分子筛最佳加入量为1.5 g,吸附30 min,Cu^(2+)去除率可达95.3%;NaA型分子筛对Cu^(2+)最大吸附容量为82.37 mg/g。 展开更多
关键词 粉煤灰 水热合成 分子筛 单相态 硅铝凝胶 吸附
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基于三维非稳态PEMFC模型的冷启动仿真 被引量:1
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作者 邓棚 高鑫 +2 位作者 张存满 郑俊生 马建新 《电源技术》 CAS CSCD 北大核心 2012年第1期36-39,共4页
建立了一种PEMFC三维非稳态单相数学模型。针对PEMFC阴极通入热空气这一辅助冷启动过程进行仿真研究,研究了通入电池阴极热空气温度和流量的变化对电池辅助冷启动过程的影响,为优化PEMFC阴极通入热空气的辅助启动策略提供理论依据。
关键词 质子交换膜燃料电池 低温启动 阴极热空气 三维非稳单相模型
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不同泄油体模式下水平井产能方程分析 被引量:8
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作者 张小龙 李晓平 +1 位作者 谢维扬 王小梅 《天然气与石油》 2012年第2期45-48,58,共5页
水平井产量计算公式众多,不同泄油体模式下的水平井产量计算公式和适用条件不同。根据油藏大小、水平井段长度及油藏边界形状等因素,将水平井泄油体分为圆柱形、椭球形和箱形三种主要模式。以单相稳态流动为基础,选择国外有代表性的水... 水平井产量计算公式众多,不同泄油体模式下的水平井产量计算公式和适用条件不同。根据油藏大小、水平井段长度及油藏边界形状等因素,将水平井泄油体分为圆柱形、椭球形和箱形三种主要模式。以单相稳态流动为基础,选择国外有代表性的水平井产能方程,对其特点和应用条件进行分析,同时阐述国内相关学者的水平井产能方程。所介绍的产能公式均是将三维流动转换为二维流动,采用复势叠加原理和镜像反映原理进行数学推导,在形式上具有明显的相似性,都是基于几种理想化的假设条件和一定的简化处理,因此预测结果与真实值存在一定误差。 展开更多
关键词 泄油体 渗流模型 单相 水平井 产能
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Effects of Compound Probiotics on Intestine and Intestinal Aeromonas hydrophila of Fish 被引量:3
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作者 朱芝秀 邓舜洲 +4 位作者 张丽珍 徐添乐 李敏 刘小兰 柳仲 《Agricultural Science & Technology》 CAS 2016年第11期2622-2626,共5页
[Objective] This study was conducted to develop compound probiotics that can be used as the alternatives of chemical drugs and antibiotics in aquaculture. [Method] Different concentrations of EM (effective microorgan... [Objective] This study was conducted to develop compound probiotics that can be used as the alternatives of chemical drugs and antibiotics in aquaculture. [Method] Different concentrations of EM (effective microorganisms) and Bacillus amyloliquefaciens were mixed at a ratio of 1:1, and sprayed on fish feed. The growth of intestinal villi of the fishes that had been fed with the feed mixed with compound probiotics for three months was observed; meanwhile, the content of in- testinal Aeromonas hydrophila was detected by real-time quantitative PCR. |Result] The compound probiotics promoted the development of intestinal villi, and inhibited the growth of A. hydrophila, and the effects were also concentration dependent. However, the compound probiotics did not increase the thickness of the intestinal serous layer, muscular layer and submucosal layer. [Conclusion] The compound probiotics we prepared can be used and popularized in aquiculture as it can inhibit the growth of A. hydrophila. 展开更多
关键词 PROBIOTICS Aeromonas hydrophila EFFECTS
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Polymorphism of Exon 3 of MHC Class Ⅱ B Gene in Chinese Alligator(Alligator sinensis)
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作者 刘辉 吴孝兵 +1 位作者 晏鹏 蒋志刚 《Journal of Genetics and Genomics》 SCIE CAS CSCD 北大核心 2007年第10期918-929,共12页
The polymorphism of MHC class II B gene in 14 Chinese alligators was analyzed, which came from three different areas: a wild population from Xuancheng, Anhui, a captive population from Changxing, Zhejiang, and a capt... The polymorphism of MHC class II B gene in 14 Chinese alligators was analyzed, which came from three different areas: a wild population from Xuancheng, Anhui, a captive population from Changxing, Zhejiang, and a captive population from Anhui Research Center for Reproduction of Chinese Alligators. The gene fragment was amplified using a pair of specific primers designed from the MHC gene sequence of the spectacled caiman. A total of 34 sequence haplotypes of exon 3 were detected in the sampled Chinese alligators. The numbers of haplotypes of the 3 Chinese alligator populations were 15, 10, and 9, respectively. The overall estimation of the MHC polymorphism in the Chinese alligator population was higher than those in mammals and in cypdnid fish, The rates of nonsynonymous substitutions (dN) occurred at a significantly lower frequency than that of synonymous substitutions (ds), which were not consistent with the common rule. This result might suggest that the polymorphism of exon 3 seemed not to be maintained by the balancing selection. The neutrality test of Tajima excluded the null hypothesis that the polymorphism of exon 3 was generated by a random drift, and the fact that D = -0.401 indicated an excess of rare mutations in the Chinese alligator. The nucleotide diversity of the sequences and the phylogenetic relations were also analyzed, and the results suggested that there was no significant difference in genetic diversity among the 3 populations of Chinese alligator. 展开更多
关键词 Chinese alligator (Alligator sinensis) major histocompatibility complex (MHC) POLYMORPHISM HAPLOTYPE
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W火焰炉炉内流动特性的试验研究 被引量:2
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作者 姜健 《节能技术》 CAS 2013年第3期223-226,231,共5页
为摸清从国外引进的一台330 MW W火焰锅炉炉内流动特性,依据相似模化的准则,对该锅炉建立了1∶10冷态单相试验台,在试验台上进行了变锅炉配风(即三次风占总二次风的比例R=0%、6%、14%、20%和27%共5个工况)的冷态模化试验,得出了炉内流... 为摸清从国外引进的一台330 MW W火焰锅炉炉内流动特性,依据相似模化的准则,对该锅炉建立了1∶10冷态单相试验台,在试验台上进行了变锅炉配风(即三次风占总二次风的比例R=0%、6%、14%、20%和27%共5个工况)的冷态模化试验,得出了炉内流场特征和拱部下行气流衰减规律。当R=0~6%时炉内流场基本对称,R值加大至14%后炉内流场出现偏斜现象,继续加大R值,则流场偏斜加剧,前、后墙侧下行气流的衰减特性差异变大。 展开更多
关键词 W火焰炉 单相模化试验 流场 风量分配
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A single-phase turbulent flow numerical simulation of a cyclonic-static micro bubble flotation column 被引量:7
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作者 Yan Xiaokang Liu Jiongtian +1 位作者 Cao Yijun Wang Lijun 《International Journal of Mining Science and Technology》 2012年第1期95-100,共6页
Improved fluid dynamics can enhance the separation efficiency of flotation methods. A Computational Fluid Dynamics simulation using FLUENT was performed to model the fluid environment of a cyclonic-sta- tic micro bubb... Improved fluid dynamics can enhance the separation efficiency of flotation methods. A Computational Fluid Dynamics simulation using FLUENT was performed to model the fluid environment of a cyclonic-sta- tic micro bubble flotation column. The simulation results visually show the interior flow and illustrate mix- ing of the different flows within the apparatus. An analysis of the distribution in velocity and vorticity was used to analyze the separation mechanism and the synergism of the component parts and to strengthen the design of each unit. The conclusions are that axial back mixing and vortexes still exist in the separation unit even in the presence of packing media. The inverted cone structure near the tangential inlet (cone 1 ) within the cyclonic unit is the main reason for this. The cone 1 structure enhances swirling and focuses energy within the inner area of the cone where there are abundant bubbles. As a result slowly floating minerals are forcibly recovered and railings are effectively separated within this unit. However, cone 1 also reduces the vorticity downstream from it, which reduces the efficiency of railings separation within this part. Therefore, the design of cone 1 should be based on the principles of lessening disturbances to the column unit while strengthening the separation effect of the cyclonic unit. Also, the axial distance between the paired cyclonic structures at the bottom of the column (cone 2) and cone 1 poses tough requirements because of an interaction between separation of the middlings and railings. 展开更多
关键词 Cyclonic-static micro bubble flotationcolumn CFD Flow field Vorticity magnitude Optimization design
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An efficient strategy for photocatalytic hydrogen peroxide production over oxygen-enriched graphitic carbon nitride with sodium phosphate 被引量:2
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作者 Yu Zhang Ling Zhang +4 位作者 Di Zeng Wenjing Wang Juxue Wang Weimin Wang Wenzhong Wang 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 2022年第10期2690-2698,共9页
Photocatalytic hydrogen peroxide(H_(2)O_(2))production is a promising strategy to replace the traditional production processes;however,the inefficient H_(2)O_(2) productivity limits its application.In this study,oxyge... Photocatalytic hydrogen peroxide(H_(2)O_(2))production is a promising strategy to replace the traditional production processes;however,the inefficient H_(2)O_(2) productivity limits its application.In this study,oxygen-rich g-C_(3)N_(4) with abundant nitrogen vacancies(OCN)was synthesized for photocatalytic H_(2)O_(2) production.X-ray photoelectron spectroscopy and Fourier-transform infrared spectroscopy indicated that oxygen-containing functional groups(–COOH and C–O–C)were obtained.Electron paramagnetic resonance confirmed the successful introduction of nitrogen vacancies.OCN exhibited efficient photocatalytic H_(2)O_(2) production performance of 1965μmol L^(−1) h^(−1) in air under visible-light irradiation.The high H_(2)O_(2) production was attributed to the enhanced adsorption of oxygen,enlarged specific surface area,and promoted carrier separation.An increased H_(2)O_(2) production rate(5781μmol L^(−1) h^(−1))was achieved in a Na_(3)PO_(4) solution.The improved performance was attributed to the changed reactive oxygen species.Specifically,the adsorbed PO_(4)^(3−) on the surface of the OCN promoted the transfer of holes to the catalyst surface.•O_(2)−obtained by O_(2) reduction reacted with adjacent holes to generate 1O_(2),which could efficiently generate H_(2)O_(2) with isopropanol.Additionally,PO_(4)^(3−),as a stabilizer,inhibited the decomposition of H_(2)O_(2). 展开更多
关键词 PHOTOCATALYSIS Hydrogen peroxide production Graphitic carbon nitride Singlet oxygen Sodium phosphate
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Coherent States and a Path Integral for the Relativistic Linear Singular Oscillator
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作者 S.M.Nagiyev E.I.Jafarov M.Y.Efendiyev 《Communications in Theoretical Physics》 SCIE CAS CSCD 2008年第2期315-318,共4页
The SU(1,1) coherent states for a relativistic model of the linear singular oscillator are considered. The corresponding partition function is evaluated. The path integral for the transition amplitude between SU(1,... The SU(1,1) coherent states for a relativistic model of the linear singular oscillator are considered. The corresponding partition function is evaluated. The path integral for the transition amplitude between SU(1,1) coherent states is given. Classical equations of the motion in the generalized curved phase space are obtained. It is shown that the use of quasiclassical Bohr Sommerfeld quantization rule yields the exact expression for the energy spectrum. 展开更多
关键词 relativistic linear singular oscillator SU(1 1) coherent states path integral
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Quantum Entropy of Black Hole with Internal Global Monopole 被引量:4
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作者 HANYi-Wen YANGShu-Zheng LIUWen-Biao 《Communications in Theoretical Physics》 SCIE CAS CSCD 2005年第2期382-384,共3页
Using the generalized uncertainty relation, the new equation of state density is obtained, and then the entropy of black hole with an internal global monopole is discussed. The divergence that appears in black hole en... Using the generalized uncertainty relation, the new equation of state density is obtained, and then the entropy of black hole with an internal global monopole is discussed. The divergence that appears in black hole entropy calculation through original brick-wall model is overcome. The result of the direct proportion between black hole entropy and its event horizon area is drawn and given. The result shows that the black hole entropy must be the entropy of quantum state near the event horizon. 展开更多
关键词 generalized uncertainty relation state density quantum entropy black hole
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Single Nucleotide Polymorphism of FSHβ Gene Associated with Reproductive Traits in Japanese Flounder (Paralichthys olivaceus) 被引量:4
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作者 HE Feng WEN Haishen +8 位作者 YU Dahui LI Jifang SHI Bao CHEN Caifang ZHANG Jiaren JIN Guoxiong CHEN Xiaoyan Shi Dan Yang Yanping 《Journal of Ocean University of China》 SCIE CAS 2010年第4期395-398,共4页
Follicle stimulating hormone β (FSHβ) of Japanese flounder (Paralichthys olivaceus) plays a key role in the regulation of gonadal development.This study aimed to investigate molecular genetic characteristics of the ... Follicle stimulating hormone β (FSHβ) of Japanese flounder (Paralichthys olivaceus) plays a key role in the regulation of gonadal development.This study aimed to investigate molecular genetic characteristics of the FSHβ gene and elucidate the effects of single nucleotide polymorphisms (SNPs) of FSHβ on reproductive traits in Japanese flounder.We used polymerase chain reaction single-strand conformation polymorphism (PCR-SSCP) and sequencing of the FSHβ gene in 60 individuals.We identified only an SNP (T/C) in the coding region of exon3 of FSHβ.The SNP (T/C) did not lead to amino acid changes at the position 340 bp of FSHβ gene.Statistical analysis showed that the SNP was significantly associated with testosterone (T) level and gonadosomatic index (GSI) (P<0.05).Individuals with genotype TC of the SNP had significantly higher serum T levels and GSI (P<0.05) than that of genotype CC.Therefore, FSHβ gene could be a useful molecular marker in selection for prominent reproductive trait in Japanese Flounder. 展开更多
关键词 Japanese flounder FSHΒ SNP reproductive trait
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A Study on Neutral Point Earthed Method of Power System
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作者 Feigao Li Yanhua Meng Shaobing Shi 《International Journal of Technology Management》 2013年第3期5-7,共3页
This paper mainly is study on power system working state with neutral point different grounded methods, when the power system is normal working and the single-phase grounding. And further analysis of the different ope... This paper mainly is study on power system working state with neutral point different grounded methods, when the power system is normal working and the single-phase grounding. And further analysis of the different operating modes of voltage and current relationships, expounds the different operation occasions and characteristics. 展开更多
关键词 power system neutral point grounded methods
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Association of NOD1 and NOD2 genes polymorphisms with Helicobacter pylori related gastric cancer in a Chinese population 被引量:9
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作者 Peng Wang Li Zhang +8 位作者 Jian-Ming Jiang Dan Ma Hao-Xia Tao Sheng-Ling Yuan Yan-Chun Wang Ling-Chun Wang Hao Liang Zhao-Shan Zhang Chun-Jie Liu 《World Journal of Gastroenterology》 SCIE CAS CSCD 2012年第17期2112-2120,共9页
AIM:To investigate the association between the tag single nucleotide polymorphisms(TagSNPs) of NOD1 and NOD2 and the risk of developing gastric cancer.METHODS:We conducted a hospital-based case-control study including... AIM:To investigate the association between the tag single nucleotide polymorphisms(TagSNPs) of NOD1 and NOD2 and the risk of developing gastric cancer.METHODS:We conducted a hospital-based case-control study including 296 incident gastric cancer patients and 160 gastritis controls.Eight TagSNPs in the NOD1 and NOD2 genes were selected from the Hapmap database using the haploview software and genotyped by the Sequenom MassArray system.The serum levels of anti-Helicobacter pylori(H.pylori) IgG were measured by enzyme-linked immunosorbent assay to indicate H.pylori infection.The odds ratios(OR) and 95% confidence intervals(CI) were calculated by unconditional logistic regression,including sex and age as confounding factors.RESULTS:The NOD1 rs2907749 GG genotype showed a decreased risk for gastric cancer(OR 0.50,95% CI:0.26-0.95,P = 0.04) while the rs7789045 TT genotype showed an increased risk(OR 2.14,95% CI:1.20-3.82,P = 0.01).An elevated susceptibility to gastric cancer was observed in the subjects with H.pylori infection and the NaOD1 rs7789045 TT genotype(OR 2.05,95% CI:1.07-3.94,P = 0.03) or the NOD2 rs7205423 GC genotype(OR 2.52,95% CI:1.05-6.04,P = 0.04).Haplotype analysis suggested that the distribution of AGT(rs2907749,rs2075820 and rs7789045) in NOD1 between the cases and control groups was significantly different(P corrected:0.04),and the diplotype AGT/AGT was associated with an elevated gastric cancer risk(OR 1.98,95% CI:1.04-3.79,P = 0.04).The association of the NOD1 rs7789045 TT genotype and the diplotype AGT/AGT was significant with H.pylori-related diffuse-type gastric cancer(OR 3.00,95% CI:1.38-6.53,P = 0.01;OR 4.02,95% CI:1.61-10.05,P < 0.01,respectively).CONCLUSION:Genetic polymorphisms in NOD1 and NOD2 may interact with H.pylori infection and may play important roles in promoting the development of gastric cancer in the Chinese population. 展开更多
关键词 Gastric cancer NOD1 NOD2 Gene polymorphisms Helicobacter pylori infection
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Separability of Pure States and Mixed States of the Quantum Network of Two Nodes
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作者 GUZhi-Yu QIANShang-Wu 《Communications in Theoretical Physics》 SCIE CAS CSCD 2003年第4期421-424,共4页
This article discusses the separability of the pure states and mixed states of the quantum network of two nodes by means of the criterion of no entanglement in terms of the covariance correlation tensor in quantum net... This article discusses the separability of the pure states and mixed states of the quantum network of two nodes by means of the criterion of no entanglement in terms of the covariance correlation tensor in quantum network theory, i.e. for a composite system consisting of two nodes. The covariance correlation tensor is equal to zero for all possible and . 展开更多
关键词 covariance correlation tensor in quantum network theory criterion of no entanglement pure state mixed state
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Singlet-Triplet Transitions of a Poeschl-Teller Quantum Dot
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作者 XIE Wen-Fang 《Communications in Theoretical Physics》 SCIE CAS CSCD 2006年第6X期1101-1104,共4页
We study the energy spectra of a two-dimensional two-electron quantum dot (QD) with P6schl-Tefler confining potential under the influence of perpendicular homogeneous magnetic field. Calculations are made by using t... We study the energy spectra of a two-dimensional two-electron quantum dot (QD) with P6schl-Tefler confining potential under the influence of perpendicular homogeneous magnetic field. Calculations are made by using the method of numerical diagonalization of Hamiltonian matrix within the effectlve-mass approximation. A ground-state behavior (spin singlet-triplet transitions) as a function of the strength of a magnetic field is found. We find that the dot radius R of a Poeschl-Teller potential is important for the ground-state transition and the feature of ground-state for a Poeschl Teller QD and a parabolic QD is similar when R is larger. The larger the well depth, the higher the magnetic field for the singlet-triplet transition of the ground-state of two interacting electrons in a Poesehl-Teller QD. 展开更多
关键词 electron-electron interaction quantum dot SEMICONDUCTOR
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Entropy and Entanglement in Master Equation of Effective Hamiltonian for Jaynes-Cummings Model
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作者 H.A.Hessian F.A.Mohammed A.-B.A.Mohamed 《Communications in Theoretical Physics》 SCIE CAS CSCD 2009年第4期723-728,共6页
In this paper, we analytically solve the master equation for Jaynes-Cummings model in the dispersive regime including phase damping and the field is assumed to be initially in a superposition of coherent states. Using... In this paper, we analytically solve the master equation for Jaynes-Cummings model in the dispersive regime including phase damping and the field is assumed to be initially in a superposition of coherent states. Using an established entanglement measure based on the negativity of the eigenvalues of the partially transposed density matrix we find a very strong sensitivity of the maximally generated entanglement to the amount of phase damping. Qualitatively this behavior is also reflected in alternative entanglement measures, but the quantitative agreement between different measures depends on the chosen noise model The phase decoherence for this model results in monotonic increase in the total entropy while the atomic sub-entropy keeps its periodic behaviour without any effect. 展开更多
关键词 ENTANGLEMENT phase damping master equation superposition state
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A simplified model to predict blast response of CFST columns 被引量:1
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作者 ZHANG Jun-hao CHEN Bin JIANG Shi-yong 《Journal of Central South University》 SCIE EI CAS CSCD 2017年第3期683-691,共9页
In order to study the dynamic response of concrete-filled steel tube(CFST) columns against blast loads,a simplified model is established utilizing the equivalent single-degree-of-freedom(SDOF) method,which considers t... In order to study the dynamic response of concrete-filled steel tube(CFST) columns against blast loads,a simplified model is established utilizing the equivalent single-degree-of-freedom(SDOF) method,which considers the non-uniform distribution of blast loads on real column and the axial load-bending moment(P-M) interaction of CFST columns.Results of the SDOF analysis compare well with the experimental data reported in open literature and the values from finite element modeling(FEM) using the program LS-DYNA.Further comparisons between the results of SDOF and FEM analysis show that the proposed model is effective to predict the dynamic response of CFST columns with different blast conditions and column details.Also,it is found that the maximum responses of the columns are overestimated when ignoring the non-uniformity of blast loads,and that neglecting the effect of P-M interaction underestimates the maximum response of the columns with large axial load ratio against close range blast.The proposed SDOF model can be used in the design of the blast-loaded CFST columns. 展开更多
关键词 concrete-filled steel tube (CFST) columns dynamic response single-degree-of-freedom (SDOF) analysis non-uniformblast loads axial load-bending moment (P-M) interaction
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The entanglement evolution of two coupling two-level atoms interacting with a single-mode vacuum field in multiphoton Tavis-Cummings model
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作者 Lu Daoming 《Engineering Sciences》 EI 2012年第1期80-85,共6页
Using multipohton Tavis-Cummings model,the entanglement evolution of two coupling two-level atoms in Bell states interacting with a single-mode vacuum field is investigated by using negativity.The influences of coupli... Using multipohton Tavis-Cummings model,the entanglement evolution of two coupling two-level atoms in Bell states interacting with a single-mode vacuum field is investigated by using negativity.The influences of coupling constants between atoms,the atomic initial states and the photon number of transition on the entanglement evolution of two coupling two-level atoms are discussed.The results obtained using the numerical method show that the entanglement of two atoms is related with coupling constants between atoms,the atomic initial states and the photon number of transition.The two-atom entanglement state will forever stay in the maximum entanglement state when the initial state is β11〉.When the initial state of two atoms is β01〉,the entanglement of two atoms displays periodic oscillation behavior.And its oscillation period decreases with increasing of coupling constant between atoms or the photon number of transition.On the other hand,when the initial state is β00〉 or β10〉,the entanglement of two atoms displays quasiperiodic oscillation behavior and its oscillation period decreases with increasing of coupling constant between atoms or the photon number of transition. 展开更多
关键词 quantum optics single-mode vacuum field two coupling two-level atoms muhiphoton ENTANGLEMENT
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水电站地下主厂房施工通风动态数值模拟 被引量:11
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作者 王晓玲 刘雪朋 +2 位作者 张自强 李涛 安娟 《工程力学》 EI CSCD 北大核心 2009年第12期175-180,188,共7页
在考虑了支洞和主变洞影响的情况下,以某水电站地下主厂房四层施工通风为例,对主厂房施工通风的风流组织和污染物扩散过程进行了模拟研究。结果表明:由工作面至出口,速度逐渐减小,主厂房内大部分区域速度小于0.15m/s,X-Y剖面处存在涡流... 在考虑了支洞和主变洞影响的情况下,以某水电站地下主厂房四层施工通风为例,对主厂房施工通风的风流组织和污染物扩散过程进行了模拟研究。结果表明:由工作面至出口,速度逐渐减小,主厂房内大部分区域速度小于0.15m/s,X-Y剖面处存在涡流区;在主厂房内出口处存在一个高浓度区,且主厂房内的CO和粉尘分布趋势相似,并以Nakayama等的矿井通风甲烷浓度分布实验结果进行了验证,模拟结果与实验基本吻合。 展开更多
关键词 水电站地下主厂房 非稳单相流模型 施工通风 CO浓度分布 粉尘浓度分布
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Direct Numerical Simulation of Convective Heat Transfer in a Zero-Pressure-Gradient Boundary Layer with Supercritical Water 被引量:2
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作者 C. Azih J.R. Brinkerhoff M.I. Yaras 《Journal of Thermal Science》 SCIE EI CAS CSCD 2012年第1期49-59,共11页
Experimental research has long shown that forced-convective heat transfer in wall-bounded turbulent flows of fluids in the supercritical thermodynamic state is not accurately predicted by correlations that have been d... Experimental research has long shown that forced-convective heat transfer in wall-bounded turbulent flows of fluids in the supercritical thermodynamic state is not accurately predicted by correlations that have been developed for single-phase fluids in the subcritical thermodynamic state. In the present computational study, the statistical properties of turbulent flow as well as the development of coherent flow structures in a zero-pressuregradient flat-plate boundary layer are investigated in the absence of body forces, where the working fluid is in the supercritical thermodynamic state. The simulated boundary layers are developed to a friction Reynolds number of 250 for two heat-flux to mass-flux ratios corresponding to cases where normal heat transfer and improved heat transfer are observed. In the case where improved heat transfer is observed, spanwise spacing of the near-wall coherent flow structures is reduced due to a relatively less stable flow environment resulting from the lower magnitudes of the wall-normal viscosity-gradient profile. 展开更多
关键词 boundary layer TURBULENCE supercritical fluids improved heat transfer DNS
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