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Modifications in aroma characteristics of'Merlot'dry red wines aged in American,French and Slovakian oak barrels with different toasting degrees
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作者 Haocheng Lu Binhao Cheng +2 位作者 Yibin Lan Changqing Duan Fei He 《Food Science and Human Wellness》 SCIE CSCD 2024年第1期381-391,共11页
Aging in oak barrels is widely used in enology which could bring flavor changes and aromatic complexity to wines.In the present study,the aroma compounds were analyzed from the‘Merlot’dry red wines,which were fermen... Aging in oak barrels is widely used in enology which could bring flavor changes and aromatic complexity to wines.In the present study,the aroma compounds were analyzed from the‘Merlot’dry red wines,which were fermented in two types of fermenters(stainless steel tank and rotated oak barrel)and aged in six types of oak barrels(three geographic origins×two toasting degrees)for different time(0,3,6 and 9 months,respectively).Results showed that 30 volatiles were associated with barrels and increased during oak aging.The fermenters could influence the intensities of the toast,leathery,smoky,fruity,floral and caramel aromas.The concentration of whisky lactone,eugenol,cis-isoeugenol,and the intensities of the toast and spicy aromas were highest in the wines aged in American oak and were lowest in the wines aged in French oak barrels.The concentrations of guaiacol,syringol,trans-isoeugenol,furfural alcohol,vanilla,cis-whisky lactone enabled the medium toasting barrels to be distinguished from the light toasting ones.The compounds originating from the barrels could be used to distinguish the types of different barrels,but the other general grape-derived and fermentation-derived volatiles could not.The fermenters,oak species and toasting degrees of the barrels all had significant effects on the aroma profiles of the aged‘Merlot’dry red wines,but the influence of the geographic origin was not obvious. 展开更多
关键词 Wine Aroma Oak Barrel Oak species Toasting degrees Geographic origin Aging
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The detrimental effect of autofrettage on externally cracked modern tank gun barrels 被引量:1
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作者 M.Perl T.Saley 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2019年第2期146-153,共8页
Overstraining gun tubes has a twofold advantage. First, it enables the increase of the Safe Maximum Pressure(SMP) in the tube, resulting in a higher muzzle velocity which extends the gun's range and its projectile... Overstraining gun tubes has a twofold advantage. First, it enables the increase of the Safe Maximum Pressure(SMP) in the tube, resulting in a higher muzzle velocity which extends the gun's range and its projectile kinetic energy. Second, it reduces the tube's susceptibility to internal cracking which prolongs its fatigue life. Unfortunately, autofrettage also bears an inherent detrimental effect as it considerably increases the tensile hoop stress at the outer portion of the barrel's wall, which enhances external cracking of the tube by increasing the prevailing Stress Intensity Factor(SIF). In order to quantify this disadvantageous effect, 3-D Mode I SIFs distributions along the front of a single external radial semielliptical crack initiating from the outer surface of an autofrettaged modern gun barrel, overstrained by either the Swage or the Hydraulic autofrettage processes, are evaluated. The analysis is performed by the finite element(FE) method, using singular elements along the crack front. Innovative residual stress fields(RSFs), incorporating the Bauschinger effect for both types of autofrettage are applied to the barrel.Hill's [1] RSF is also applied to the tube for comparison reasons. All three RSFs are incorporated in the FE analysis, using equivalent temperature fields, Values for K_(IA)-the SIF resulting from the tensile residual stresses induced by autofrettage are evaluated for: a typical barrel of radii ratio R_o/R_i = 2, crack depth to wall-thickness ratios(a/t = 0.005-0.1),crack ellipticities(a/c = 0.2-1.0),and five levels of Swage,Hydraulic and Hill's autofrettage(e = 40%,60%,70%,80%,and 100%). In total,375 different 3-D cases are analyzed. The analysis demonstrates undoubtedly the detrimental effect of all types of autofrettage in increasing the prevailing effective stress intensity factor of external cracks, resulting in crack initiation enhancement and crack growth rate acceleration which considerably shortens the total fatigue life of the barrel. Nonetheless, the detrimental effect is autofrettage-type dependent. Swage and Hydraulic autofrettage RSFs differ substantially from each other. The disadvantageous effect of Swage autofrettage is much greater than that resulting from Hydraulic autofrettage. The results also emphasize the significance of the Bauschinger effect and the importance of the 3-D analysis. 展开更多
关键词 GUN BARREL Swage and HYDRAULIC AUTOFRETTAGE External CRACK 3-D Finite element
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Cortical columns(barrels)display normal size in the brain’s primary somatosensory cortex of mice carrying null mutations of the insulin receptor substrate 1 gene:A preliminary report
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作者 Marta Lopez-Santibanez Guevara Eileen Uribe-Querol +3 位作者 Alma Lilia Fuentes Farias Esperanza Melendez-Herrera Agustine Joseph D’Ercole Gabriel Gutierrez-Ospina 《Advances in Bioscience and Biotechnology》 2013年第10期945-948,共4页
Circuits in barrels of the rodent brain’s primary somatosensory (S1) cortex build up following constructivist rules. Previous evidence in mice supports that the precise addition of barrel neuropil is promoted by insu... Circuits in barrels of the rodent brain’s primary somatosensory (S1) cortex build up following constructivist rules. Previous evidence in mice supports that the precise addition of barrel neuropil is promoted by insulin-like growth factor-1 (IGF-1). The signaling cascades mediating this response remain undetermined. To address whether the effects of IGF-1 upon the growth of S1 circuits are mediated by insulin receptor substrate-1 (IRS-1), we studied barrel size in adult mice having the IRS-1 gene knocked out (IRS-1 ko). Our results reveal that barrel size is similar between wild type and IRS-1 ko mice suggesting that IRS-1 is not essential for barrel circuitry growth. Hence, investigations aimed at exploring other substrates activated by IGF-1, namely IRS-2 and IRS-4, are needed to reveal signaling pathways that mediate the precise addition of S1 neuronal circuitry. 展开更多
关键词 Barrel Cortex Neuronal Circuit Assemblage Trophic Interactions CONSTRUCTIVISM
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Symbols in The Magic Barrel
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作者 FU He-yuan 《Journal of Literature and Art Studies》 2024年第1期48-53,共6页
The article takes the famous modern American Jewish writer Bernard Malamud’s novel The Magic Barrel as the object of study,and uses symbolism to interpret it,analyzing it one by one in terms of the magic barrel,the c... The article takes the famous modern American Jewish writer Bernard Malamud’s novel The Magic Barrel as the object of study,and uses symbolism to interpret it,analyzing it one by one in terms of the magic barrel,the colors,the seasons and the windows,respectively,so as to reveal the process of getting rid of the childishness within the novel’s male protagonist,Leo Finkel,who is maturing,as well as the novel’s Jewish theme of searching for the soul of the self. 展开更多
关键词 SYMBOL magic barrel WINDOW
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金卤灯汞蒸汽压的光谱学测定
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作者 龙奇 陈大华 《照明工程学报》 2007年第4期33-37,共5页
本文探讨了金属卤化物灯中汞蒸汽压的各种测定方法;并用Bartels方法测量了NavarNEC10000K70W金卤灯等离子体温度轮廓,用Abel转换测定Hg577nm和579nm谱线的发射系数,在此基础上,通过比较两次诊断的灯管中心温度进而确定此金卤灯额定功率... 本文探讨了金属卤化物灯中汞蒸汽压的各种测定方法;并用Bartels方法测量了NavarNEC10000K70W金卤灯等离子体温度轮廓,用Abel转换测定Hg577nm和579nm谱线的发射系数,在此基础上,通过比较两次诊断的灯管中心温度进而确定此金卤灯额定功率稳态运行过程中的Hg蒸汽压。 展开更多
关键词 汞蒸汽压 barrels方法 Abel转换 光谱学
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去胡须对大鼠行为及桶状皮层的影响 被引量:1
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作者 孙缦利 张小兵 +2 位作者 孙霞 赵孟辉 虞燕琴 《中国应用生理学杂志》 CAS CSCD 北大核心 2010年第3期354-358,共5页
目的:研究外周去胡须后大鼠行为及桶状皮层(barrel cortex,BC)的可塑性变化。方法:SD大鼠随机分组(n=4):正常对照(A组),出生后第2天去除双侧颊脂垫组(B组),出生后第2天去除右侧颊脂垫组(C组),出生后1~5d每天剪右侧胡须,从出生后第5天... 目的:研究外周去胡须后大鼠行为及桶状皮层(barrel cortex,BC)的可塑性变化。方法:SD大鼠随机分组(n=4):正常对照(A组),出生后第2天去除双侧颊脂垫组(B组),出生后第2天去除右侧颊脂垫组(C组),出生后1~5d每天剪右侧胡须,从出生后第5天起不剪由其胡须自由生长组(D组)。出生后第30天时称体重,测量左侧D2胡须长度,观测行为学变化(如狭缝实验、自由探索行为和趋壁行为)。采用细胞色素氧化酶组织化学法研究barrel排列与发育情况。结果:A组能迅速辨别出正确狭缝并钻入,平均用时(5.6±2.3)s;B组大鼠只有当鼻尖碰到狭缝壁时才会钻入狭缝。C组大鼠当其右侧脸颊靠近狭缝时,不能辨别出狭缝,只有当其掉转身体,用左侧胡须探测时才可能迅速钻入正确的狭缝。D组的表现同C组,B、C、D组大鼠进入正确狭缝的所用时间均显著长于A组(P<0.01,P<0.05,P<0.01)。去除双侧颊脂垫的大鼠其左趋壁时间、右趋壁时间以及总趋壁时间均较正常大鼠短。去除右侧颊脂垫组的大鼠右趋壁时间也显著短于正常(P<0.05)。四组大鼠左侧D2胡须长度以及体重均无显著差异。从出生后第2天时一直剪除右侧胡须的小鼠在出生后第30天时发现其barrel变小,排列较混乱,barrel之间的界限不清,皮层细胞色素氧化酶(CO)反应的灰度明显变淡。结论:外周去传入不引起大鼠体重改变及残留胡须长度的代偿性改变,但可引起其趋触及探索行为方面的改变。外周去传入可导致barrel形状及排列的可塑性变化。 展开更多
关键词 Barrel皮层 胡须 可塑性 去传入
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一种内窥镜变形矫正新方法 被引量:1
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作者 王宏志 郝红卫 《计算机研究与发展》 EI CSCD 北大核心 2004年第6期1010-1015,共6页
由于内窥镜透镜的特性 ,从内窥镜获得的图像有严重的“barrel”变形 ,在内窥镜的应用中对内窥镜变形进行矫正是必需的 Asari和ChaoZhang等人提出了基于最小平方误差的变形矫正的技术 ,但是 ,他们的方法并没有将变形中心作为可调节的变... 由于内窥镜透镜的特性 ,从内窥镜获得的图像有严重的“barrel”变形 ,在内窥镜的应用中对内窥镜变形进行矫正是必需的 Asari和ChaoZhang等人提出了基于最小平方误差的变形矫正的技术 ,但是 ,他们的方法并没有将变形中心作为可调节的变量进行修正 然而 ,实际对变形中心的估计是有误差的 ,而且变形中心的精确程度对整个变形矫正的效果有很大影响 ,所以对ChaoZhang的方法进行了改进 ,把变形中心作为可调节参数 ,应用优化方法对其进行调整 。 展开更多
关键词 内窥镜 变形矫正 “barrel”变形 镜头校准
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SD大鼠Barrel脑区氧化酶活性区域及其特殊细胞构筑研究
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作者 郑小敏 范光丽 +2 位作者 范增杰 张永德 王晋辉 《西北农林科技大学学报(自然科学版)》 CSCD 北大核心 2008年第6期10-14,20,共6页
【目的】确定控制大鼠胡须感觉的大脑皮质Barrel脑区的氧化酶活性区和该区的细胞构筑,为研究大脑皮质功能奠定基础。【方法】用多聚甲醛固定后的SD鼠脑组织修块、切片,应用氧化酶酶组织化学法及尼氏染色和尼氏复染等方法定位了SD鼠Bar... 【目的】确定控制大鼠胡须感觉的大脑皮质Barrel脑区的氧化酶活性区和该区的细胞构筑,为研究大脑皮质功能奠定基础。【方法】用多聚甲醛固定后的SD鼠脑组织修块、切片,应用氧化酶酶组织化学法及尼氏染色和尼氏复染等方法定位了SD鼠Barrel脑区,并观察了其脑区特殊的细胞构筑。【结果】SD鼠Barrel脑区定位结果表明,控制SD鼠胡须感觉的Barrel脑区高氧化酶活性区域位于皮层下约405~720μm;脑区的神经细胞成特殊的环状分布,通常在控制1根胡须的Barrel桶内同时包括数目不等的亚结构,亦成类似的环状排列,在这些小圆环状亚结构中包含有排布规则的高活性氧化酶细胞。【结论】Barrel脑区的精细排布及其内部存在的圆环状细胞亚结构,提示这些结构在感觉皮层神经网络运作中发挥着重要作用。 展开更多
关键词 细胞色素氧化酶 Barrel脑区 胡须 SD鼠
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幼年及成年SD大鼠Barrel脑区的变化
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作者 郑小敏 范光丽 +2 位作者 范增杰 王跟辈 王晋辉 《解剖学报》 CAS CSCD 北大核心 2008年第5期645-648,共4页
目的研究幼年和成年SD大鼠Barrel脑区的发育及变化。方法应用细胞色素氧化酶组织化学法研究成年SD鼠Barrel脑区的精确定位,及不同年龄段SD大鼠(出生后20d及3月龄成年SD大鼠)Barrel脑区的发育情况。结果成年SD大鼠的Barrel脑区面积明显... 目的研究幼年和成年SD大鼠Barrel脑区的发育及变化。方法应用细胞色素氧化酶组织化学法研究成年SD鼠Barrel脑区的精确定位,及不同年龄段SD大鼠(出生后20d及3月龄成年SD大鼠)Barrel脑区的发育情况。结果成年SD大鼠的Barrel脑区面积明显小于年轻鼠(P<0.01);发育过程中,Barrel脑区各列之间的间距缩小,尤其是D和E列之间的间距;应用Nissl复染后发现,分隔各个Barrel桶之间的间距缩小,且神经元数目减少;成年SD大鼠的Barrel桶中高活性细胞色素氧化酶细胞比例明显高于年轻鼠(P<0.01)。结论啮齿类动物躯体感觉皮层Barrel脑区神经网络的排布精细,其构筑在发育过程中存在着微妙的变化。 展开更多
关键词 Barrel脑区 胡须 细胞色素氧化酶组织化学法 大鼠
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Modeling and simulation of bullet-barrel interaction process for the damaged gun barrel 被引量:9
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作者 Chao Shen Ke-dong Zhou +1 位作者 Ye Lu Jun-song Li 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2019年第6期972-986,共15页
In this paper,the influences of bore damage on the bullet-barrel interaction process and the mechanism of how bore damage results in the end of a machine gun barrel’s service life were studied,which had seldom been p... In this paper,the influences of bore damage on the bullet-barrel interaction process and the mechanism of how bore damage results in the end of a machine gun barrel’s service life were studied,which had seldom been paid attention to in the past several decades.A novel finite element mesh generation method for the damaged barrel and a new transient coupled thermo-mechanical finite element(FE)model,which were based on the damage data obtained through barrel life tests,were developed to simulate the interior ballistics process of a coupled bullet-barrel system.Additionally,user subroutine VUAMP was developed in the FE model in order to take the bullet base pressure brought by propellant gas into account.Good consistency between the simulation results and the experimental results verified the preciseness of the proposed mesh generation method and the FE model.The simulation results show that the increase of bullet’s initial disturbance at the muzzle and the variation of its surface morphology caused by bore damage are primarily responsible for the life end of this 12.7 mm machine gun barrel. 展开更多
关键词 Barrel life tests Real bore damage Interior ballistics performance Initial disturbance Finite element method
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The law of barrel wear and its application 被引量:4
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作者 Ji-sheng Ma 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2018年第6期674-676,共3页
A power function relation between number of rounds and barrel wear amount is created based on the test data from firing of large-caliber barrels. The function is optimized to fully fit the test data. A new concept of ... A power function relation between number of rounds and barrel wear amount is created based on the test data from firing of large-caliber barrels. The function is optimized to fully fit the test data. A new concept of diameter change rate of bore is proposed and the law of barrel wear is put forward by means of comparing the diameter change rates for large-caliber barrels with different calibers. It is shown that the law of barrel wear is successful in barrel life prediction. 展开更多
关键词 BARREL LIFE Prediction model LAW of BARREL WEAR CURVE FITTING
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DEFORMATION BEHAVIOR OF AA6063 ALUMINIUM ALLOY AFTER REMOVING FRICTION EFFECT UNDER HOT WORKING CONDITIONS 被引量:6
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作者 Z. Y. Chen S. Q. Xu X.H. Dong 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2008年第6期451-458,共8页
The hot deformation behavior of AA6063 aluminium alloy has been investigated by means of compression tests at temperatures between 400 and 520℃, and strain rates ranging from 2.5 to 10 s^-1. Owing to the barreling, t... The hot deformation behavior of AA6063 aluminium alloy has been investigated by means of compression tests at temperatures between 400 and 520℃, and strain rates ranging from 2.5 to 10 s^-1. Owing to the barreling, the theoretical model on the basis of Hills general method is used to calculate the flow stress of a cylindrical specimen under uniaxial simple compression so as to consider the friction effect at the die-specimen interface. A method of evaluating the friction coefficient by combining compression tests with the finite element method is presented. The real flow behavior of AA6063 aluminium alloy can be described with sinh-Arrhenius equation. The hot deformation activation energy Q derived from the corrected stress and strain data is 232. 350 kJ/mol. 展开更多
关键词 Barreling Compression test FRICTION Flow stress Aluminium alloy Activation energy
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The Morphology and Structure of GABAergic Neurons in BARREL and VPM
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作者 范增杰 曹志恒 王子仁 《Agricultural Science & Technology》 CAS 2008年第1期81-84,共4页
To understand the structure of GABAergic neurons in the VMP and "barrel", the distribution of GABAergic neurons in the two areas were studied through immunohistochemistry and Laser Scanning Confocal Microscope. The ... To understand the structure of GABAergic neurons in the VMP and "barrel", the distribution of GABAergic neurons in the two areas were studied through immunohistochemistry and Laser Scanning Confocal Microscope. The results show that the distribution of GABAergic neurons in VMP and barrel are different, and the coding of information transmission in the two areas are also dissimilar; GABAergic neurons mainly distribute among the lines asymmetrically in VMP, the somata, dendrite and axon of GABAergic neurons are restricted in the "barrel", rarely having synaptic connections with other "barrel" around. Therefore, VMP and barrel may have different roles in transmission and on processing of informatiton. 展开更多
关键词 GABAERGIC BARREL VMP SD rats IMMUNOHISTOCHEMISTRY
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GABAergic神经元在BARREL和VPM区组织结构及形态特点的免疫组织化学研究
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作者 范增杰 曹志恒 王子仁 《安徽农业科学》 CAS 北大核心 2008年第15期6332-6334,共3页
[目的]研究GABAergic神经元在VPM和"barrel"区的组织结构及形态特点;[方法]通过免疫组织化学的方法和激光共聚焦电子显微镜研究GABAergic神经元在VPM和"barrel"区分布状态;[结果]GABAergic神经元在VPM和"barre... [目的]研究GABAergic神经元在VPM和"barrel"区的组织结构及形态特点;[方法]通过免疫组织化学的方法和激光共聚焦电子显微镜研究GABAergic神经元在VPM和"barrel"区分布状态;[结果]GABAergic神经元在VPM和"barrel"区分布状态不同,信息传递这2个区域编码程度也不一样;GABAergic在VPM区主要分布在列与列之间,且呈非对称分布,而GABAergic神经元的胞体、树突和轴突出现限定在"barrel"内,与周围"barrel"很少形成突触联系。[结论]提示VPM和"barrel"可能在信息传递及处理过程中具有不同的功能。 展开更多
关键词 GABAERGIC BARREL VPM SD大鼠 免疫组织化学
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Study on performance degradation and failure analysis of machine gun barrel 被引量:4
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作者 Xiaolong Li Lei Mu +1 位作者 Yong Zang Qin Qin 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2020年第2期362-373,共12页
An increase in the use of the gun barrel will cause wear of the inner wall,which reduces the muzzle velocity and the spin rate of the projectile.The off-bore flight attitude and trajectory of the projectile also chang... An increase in the use of the gun barrel will cause wear of the inner wall,which reduces the muzzle velocity and the spin rate of the projectile.The off-bore flight attitude and trajectory of the projectile also change,affecting the shooting power and the accuracy.Exterior ballistic data of a high-speed spinning projectile are required to study the performance change.Therefore,based on the barrel’s accelerated life test,the whole process of projectile shooting is reproduced using numerical simulation technology,and key information on the ballistic performance change at each shooting stage are acquired.Studies have shown that in the later stages of barrel shooting,the accuracy of shooting has not decreased significantly.However,it is found that the angle of attack of the projectile increases as the wear of the barrel increases.The maximum angle of attack reaches 0.106 rad when the number of shots reaches 4300.Meanwhile,elliptical bullet hole has appeared on the target at this shooting stage.Through combining external ballistic theory with simulation results,the primary reason of this phenomenon is found to be a significant decrease in the muzzle spin rate of the projectile.At the end of the barrel life,the projectile muzzle spin rate is 57.5%lower than that of a barrel without wear. 展开更多
关键词 WEAR of the INNER wall ACCELERATED LIFE test Numerical simulation BALLISTIC performance End of the BARREL LIFE
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α/β类蛋白折叠中π-π相互作用的特异性
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作者 王勤 李晓琴 马帅 《高等学校化学学报》 SCIE EI CAS CSCD 北大核心 2014年第12期2674-2679,共6页
以α/β类蛋白的2种典型折叠类型为研究对象,对205个低相似度蛋白样本中的π-π相互作用进行统计分析.计算结果表明,(α/β)8-barrel折叠中π-π相互作用的分布密度高于经典Rossmann折叠,且在关键的局部区域的差异更加显著;芳香族氨基酸... 以α/β类蛋白的2种典型折叠类型为研究对象,对205个低相似度蛋白样本中的π-π相互作用进行统计分析.计算结果表明,(α/β)8-barrel折叠中π-π相互作用的分布密度高于经典Rossmann折叠,且在关键的局部区域的差异更加显著;芳香族氨基酸在(α/β)8-barrel结构中更容易形成π-π相互作用;色氨酸对应的3种π-π相互作用组合在(α/β)8-barrel折叠中出现的几率显著高于经典Rossmann折叠;(α/β)8-barrel折叠中π-π相互作用形成复杂π网络的能力强于经典Rossmann折叠.上述结果表明,π-π相互作用在α/β类蛋白的不同折叠类型中存在特异性,其在稳定(α/β)8-barrel结构中的作用强于经典Rossmann折叠. 展开更多
关键词 (α/β)8·barrel折叠 Rossmann折叠 Π-Π相互作用 π-网络 非经典相互作用
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Fluid characteristic of multiphase fluid in annular space between pump barrel and plunger 被引量:5
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作者 XING Ming-ming ZHOU Li-li +2 位作者 ZHAO Yan XUE Kai-feng ZHANG Cheng-mao 《Journal of Central South University》 SCIE EI CAS CSCD 2019年第5期1327-1341,共15页
The pump performance parameters,such as pump pressure,plunger friction and pump valve resistance,are fundamental parameters of optimal design of pump efficiency and sucker rod pumping system (SRPS).In this paper,consi... The pump performance parameters,such as pump pressure,plunger friction and pump valve resistance,are fundamental parameters of optimal design of pump efficiency and sucker rod pumping system (SRPS).In this paper,considering the characteristic of geometrical nonlinear and rheology property of multiphase fluid,the pump performance parameters are studied.Firstly,a dynamics model of annular fluid flow is built.In the detail,a partial differential equation of annular fluid is established and a computing model of fluid pressure gradient is built.Secondly,the simulation models of plunger friction and hydraulic resistance of pump valve are built.Finally,a novel simulation method of fluid pressure in annular space is proposed with software ANSYS.In order to check up the correction of models proposed in this paper,the comparison curves of experiment and simulation results are given.Based on above model,the whole simulation model of plunger pump is simulated with Visual Basic 6.0.The results show that the fluid friction of pump plunger and instantaneous resistance of pump valve are nonlinear.The impact factors of pump performance parameters are analyzed,and their characteristic curves are given,which can help to optimize the pump motion parameters and pump structural. 展开更多
关键词 sucker rod pumping system (SRPS) PUMP pump plunger pump barrel performance parameter
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Taper barrel rheomoulding process for semi-solid slurry preparation and microstructure evolution of A356 aluminum alloy 被引量:5
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作者 张帆 康永林 +1 位作者 杨柳青 丁瑞华 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2010年第9期1677-1684,共8页
The self-developed taper barrel rheomoulding (TBR) machine for light alloy semi-solid slurry preparation was introduced.The semi-solid slurry was obtained from the intense shearing turbulence of the alloy melt in the ... The self-developed taper barrel rheomoulding (TBR) machine for light alloy semi-solid slurry preparation was introduced.The semi-solid slurry was obtained from the intense shearing turbulence of the alloy melt in the cause of solidification, which was further caused by the relative rotation of the internal and external taper barrel whose surface contained wale and groove.The heat transmission model of TBR process, the flow rules and the shearing model of the alloy melt were deduced.Taking A365 as experimental material, the microstructure evolution rules under different slurry preparation processes were analyzed.The results show that decreasing the pouring temperature of A365 alloy melt properly or increasing the shearing rate helps to obtain ideal semi-solid microstructure with the primary particle size of about 70 μm and the shape factor of above 0.8. 展开更多
关键词 taper barrel rheomoulding semi-solid slurry preparation microstrncture evolution A356 aluminum alloy
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Development of multi-physics numerical simulation model to investigate thermo-mechanical fatigue crack propagation in an autofrettaged gun barrel 被引量:3
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作者 Naveed Hussain Faisal Qayyum +1 位作者 Riffat Asim Pasha Masood Shah 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2021年第5期1579-1591,共13页
In this research,a detailed multi-physics study has been carried out by numerically simulating a solid fractured gun barrel for 20 thermo-mechanical cycles.The numerical model is based on thermal effects,mechanical st... In this research,a detailed multi-physics study has been carried out by numerically simulating a solid fractured gun barrel for 20 thermo-mechanical cycles.The numerical model is based on thermal effects,mechanical stress fields and fatigue crack mechanics.Elastic-plastic material data of modified AISI 4340 at temperatures ranging from 25 to 1200℃and at strain rates of 4,16,32 and 48 s^(-1) was acquired from high-temperature compression tests.This was used as material property data in the simulation model.The boundary conditions applied are kept similar to the working gun barrel during continuous firing.A methodology has been provided to define thermo-mechanically active surface-to-surface type interface between the crack faces for a better approximation of stresses at the crack tip.Comparison of results from non-autofrettaged and autofrettaged simulation models provide useful information about the evolution of strains and stresses in the barrel at different points under combined thermo-mechanical loading cycles in both cases.The effect of thermal fatigue under already induced compressive yield due to autofrettage and the progressive degradation of the accumulated stresses due to thermo-mechanical cyclic loads on the internal surface of the gun barrel(mimicking the continuous firing scenario)has been analyzed.Comparison between energy release rate at tips of varying crack lengths due to cyclic thermo-mechanical loading in the non-autofrettaged and autofrettaged gun has been carried out. 展开更多
关键词 Steel AUTOFRETTAGE Gun barrel Crack propagation Thermo-mechanical fatigue Numerical simulation Residual stress dissipation
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A New Treatment of Depression for Drainage Network Extraction Based on DEM 被引量:4
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作者 WANG Yan PENG Hong +3 位作者 CUI Peng ZHANG Wanshun QIAO Fei CHEN Cai'er 《Journal of Mountain Science》 SCIE CSCD 2009年第4期311-319,共9页
Depressions in landscapes function as buffers for water and sediment. A landscape with depressions has less runoff, less erosion and more sedimentation than that without depressions. Sinks in digital elevation models ... Depressions in landscapes function as buffers for water and sediment. A landscape with depressions has less runoff, less erosion and more sedimentation than that without depressions. Sinks in digital elevation models (DEMs) can be considered the real features that represent depressions in actual landscapes or spurious features that result from errors in DEM creation. In many hydrological and erosion models, all sinks are considered as spurious features and, as a result, these models do not deal with the sinks that represent real depressions. Consequently, the surface runoff and erosion are overestimated due to removing the depressions. Aiming at this problem, this paper presents a new method, which deal with the sinks that represent real depressions. The drainage network is extracted without changing the original DEM. The method includes four steps: detecting pits, detecting depressions, merging depressions, and extracting drainage network. Because the elevations of grid cells are not changed, the method can also avoid producing new fiat areas, which are always produced by the conventional filling methods. The proposed method was applied to the Xihanshui River basin, the upper reach of the Jialingjiang River basin, China, to automatically extract the drainage network based on DEM. The extracted drainage network agrees well with the reality and can be used for further hydrologic analysis and erosion estimation. 展开更多
关键词 Drainage network extraction Depression processing Digital elevation model Wooden barrel effect Xihanshui River basin.
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