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Search Results: 1 - 10 of 7142 matches for " 蒲育 "
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Winkler-Pasternak弹性地基梁自由振动的二维弹性分析 Two-dimensional elastic analysis for free vibration of beams set on winkler-pasternak elastic foundations

,滕兆春
- , 2016, DOI: 10.7511/jslx201602007
Abstract: 基于二维线弹性理论,应用Hamilton原理,获得Winkler-Pasternak弹性地基梁自由振动的控制微分方程,应用微分求积法(DQM)数值研究了梁自由振动的量纲频率特性。计算结果与已有的结果(Bernoulli-Euler梁和Timoshenko梁)比较表明,本文的分析方法对弹性地基长梁和短梁自由振动的研究都有效。最后考虑了几何参数对梁频率的影响,以及不同边界条件下地基系数对频率的影响和收敛性。
Based on the two-dimension linear elasticity theory and applied the Hamilton's principle,the governing differential equations of free vibration for beam set on Winkler-Pasternak elastic foundation are derived.Using differential quadrature method (DQM),the free vibration dimensionless frequencies of beams are investigated numerically.With application of DQM in this paper,it illustrated that the method was validated and accurate for Bernoulli-Euler beams as well as for Timoshenko beams by comparison of previously reported results.Finally,the effect of the geometrical parameter on the non-dimensional frequency parameter of the beams,the influence and the convergence for dimensionless frequency owing to elastic coefficients of foundation under different boundary conditions are considered.
FGM圆环板面内自由振动的DQM求解
滕兆春,,房晓林
北京理工大学学报 , 2014,
Abstract: 基于二维线弹性理论,假定材料物性沿圆环板的径向按照幂律梯度分布,建立了FGM薄圆环板面内自由振动的运动微分方程,采用微分求积法数值研究了FGM圆环板面内自由振动的量纲一频率特性,并与各向同性材料圆环板面内自由振动的量纲一频率进行了比较,说明本文的分析方法有效.结果表明,不同边界条件,FGM梯度指标以及FGM圆环板内、外半径比对量纲一频率均有影响,其计算结果和分析方法可供设计参考.
各种典型边界FGM矩形板面内自由振动的二维弹性分析
Two-Dimensional Elasticity Solutions for In-Plane Free Vibration of FGM Rectangular Plates under Different Boundary Conditions

, 滕兆春
PU Yu
, TENG Zhaochun

- , 2016, DOI: 10.3969/j.issn.0258-2724.2016.06.020
Abstract: 为获得功能梯度材料(FGM)矩形板面内自由振动的动力学响应,基于二维线弹性理论建立了功能梯度材料矩形板面内自由振动的控制微分方程.采用微分求积法(DQM)数值研究了9种典型边界下FGM矩形板面内自由振动的频率特性,分析了边界条件、长宽比及梯度指数对自振频率的影响.分析结果表明:通过设置梯度指数为0,将FGM矩形板退化为各向同性矩形板,与已有各向同性矩形板的文献结果进行比较,表明了DQM的适用性和精确性;9种边界下长宽比对FGM矩形板基频的影响不同,基频随长宽比的增大而增大的板分别为:C-C-C-C板、SS2-C-SS2-C板、C-C-C-F板、SS1-C-SS1-C板、C-C-F-F板和SS1-SS1-SS2-SS2板;基频随长宽比的增大而减小的板分别为:F-F-F-F板与C-F-C-F板;SS1-SS1-SS1-SS1板发生剪切自锁现象,基频随长宽比的增大而基本保持不变;基频随梯度指数的增大而快速减小,梯度指数p >10时,基频变化不再明显.
: In order to obtain the dynamic responses on in-plane free vibration of functionally graded material (FGM) rectangular plates, based on the two-dimensional linear elasticity theory, the governing partial differential equations for the in-plane free vibration of FGM rectangular plates were derived. Using differential quadrature method (DQM), the frequency characteristics for in-plane free vibration of FGM rectangular plates under 9 different boundary conditions were investigated. The effects of boundary conditions, geometrical parameters and material gradient indexes on the dimensionless frequencies of the FGM rectangular plates were analyzed. The material gradient index was set as zero to take FGM rectangular plates as isotropic rectangular plates. Then, the applicability and accuracy of the DQM were demonstrated by comparing the in-plane free vibration of the obtained isotropic rectangular plates with those in literature. The effect of the length-width ratio on the fundamental frequency of the FGM rectangular plates varies under different boundary conditions. The fundamental frequency increases with the length-width ratios for the plates C-C-C-C, SS2-C-SS2-C, C-C-C-F, SS1-C-SS1-C, C-C-F-F and SS1-SS1-SS2-SS2, and decreases with the increase of the length-width ratios for the plates F-F-F-F and C-F-C-F, but has no significant changes for SS1-SS1-SS1-SS1 plate because of shear locking. The fundamental frequency decreases rapidly with the increase of material gradient indexes, but it has no obvious change when the material gradient index p is more than 10
FGM环扇形板的面内自由振动分析 In-plane free vibration analysis of FGM annular sector plates
In-plane free vibration analysis of FGM annular sector plates

滕兆春,朱亚文,
- , 2018, DOI: 10.7511/jslx20170703001
Abstract: 假定功能梯度材料(FGM)的物性参数沿环扇形板径向按照幂律梯度变化,基于平面线弹性理论,建立了FGM环扇形板面内自由振动的运动控制微分方程。采用二维微分求积法(DQM)对FGM环扇形板面内自由振动的量纲运动控制微分方程进行离散,数值求解了不同边界条件下FGM环扇形板面内自由振动的量纲固有频率,同时也给出了FGM环扇形板扇形角为π/4时有限元商用软件ANSYS的部分计算结果,验证了本文方法的正确性。结果表明,在相应边界条件下,FGM环扇形板的梯度指标、内外半径比以及扇形角对量纲固有频率均有影响,其计算结果和分析方法可供设计和研究参考。
Assuming that the material physical parameters of the annular sector plates follows a power law distribution along the radius and based on plane linear theory of elasticity,the governing differential equations of motion for in-plane free vibration of a functionally graded material (FGM) annular sector plate are established.Then using two-dimensional differential quadrature method (DQM),the dimensionless governing differential equations of motion of in-plane free vibration of FGM annular sector plates are discretized and the dimensionless natural frequencies of the in-plane free vibration of FGM annular sector plates under the corresponding boundary conditions are solved numerically.Some results of dimensionless natural frequencies of FGM annular sector plate with π/4 angle of the sector are computed by the finite element commercial software ANSYS.They show that the current method is effective and accurate.When the plates are under the corresponding boundary conditions,the results indicate that the gradient index of FGM,the internal and external radius ratio and the angle of the sector all affect the dimensionless natural frequencies,the calculation results and the analysis method can be used in design and research.
煤矿斜井冻结孔定向钻进关键装备研发
袁辉,邓昀,朝阳,董新旺,李尚泽,邵公,杨雪
煤炭科学技术 , 2015,
Abstract: 为解决目前我国西部斜井冻结施工只能采用立井垂直孔冻结技术的问题,满足斜井沿轴线冻结工艺要求,研制了应用于斜井冻结孔定向钻进关键装备,如近水平小倾角斜井冻结钻机、斜冻结孔冻结管下放装备等,通过无线随钻测斜仪测斜定向技术的现场试验和磁导向测斜定向装备的实验室研究,证明了测斜精度满足要求。这些装备和测斜技术有望解决斜井沿轴线冻结孔钻孔、下放冻结管及钻孔精度难以保证的技术难题。
小麦品系P81抗条锈性遗传分析
宗君,颜泽洪,,杨武云,郑有良
植物保护学报 , 2007,
Abstract: 小麦条锈病是小麦生产中最重要的病害,培育抗病品种是防治条锈病的有效措施。小麦品系P81在苗期和成株期对当前流行的条锈菌小种条中30、31和32均表现免疫。以感病品种川麦28、Taichung29作母本,P81作父本通过杂交分别配制了F1、F2和BC1、BC2代,用人工接种方法研究P81及其杂交后代对条中32号的苗期抗性并进行了遗传分析;同时,将P81分别与含有抗条锈基因的Yr5、Yr10、Yr15、Yr26材料进行杂交配制F2,用条中32号小种对其F2进行抗感鉴定,确定抗性基因的等位性。结果表明,P81与川麦28、Taichung29杂交F1代植株对条锈菌条中32号小种表现出与P81相似的高抗,说明P81中的抗条锈基因为显性表达。根据P81与川麦28、Taichung29杂交的F2、BC1、BC2代植株的抗性分离情况及F1代植株及亲本的抗性表现,说明P81对条中32号的抗性由1对显性抗条锈病基因控制;用条中32号小种接种鉴定P81与已知抗锈基因Yr5、Yr10、Yr15、Yr26构建的F2群体时均出现了感病植株,说明P81中的抗条锈病基因与Yr5、Yr10、Yr15、Yr26不相同;系谱分析表明,该基因来源于叙利亚普通小麦品系叙29。
芹菜对小鼠生精细胞中Bcl-2、Bax蛋白表达影响
党瑜慧,李芝兰,杜蔚云,,安婧
中国公共卫生 , 2011, DOI: 10.11847/zgggws2011-27-09-35
Abstract: ?目的探讨芹菜对小鼠生精细胞中Bcl-2、Bax蛋白表达的影响。方法成年健康SPF级昆明种雄性小鼠72只,按体重随机分为4组:对照组、低、中、高剂量芹菜汁组,各组又随机分成3个时间组即:7、14、28d组,每组6只;以0.3mL不同浓度芹菜汁灌胃,对照组以0.3mL生理盐水灌胃。实验结束处死小鼠,取一侧睾丸,免疫组织化学法(SABC)检测小鼠睾丸生精细胞Bcl-2和Bax蛋白表达。结果灌胃7d时,对照、低、中、高剂量芹菜汁组Bax蛋白表达平均光密度值分别为0.38、0.35、0.35和0.34,与对照组比较,各剂量芹菜汁组明显下降,差异有统计学意义(P<0.05);灌胃28d时,对照组Bcl-2蛋白表达平均光密度值为0.34,中、高剂量芹菜汁组分别为0.37和0.38,明显高于对照组,差异有统计学意义(P<0.05)。结论本实验条件下未观察到芹菜对生精细胞的促凋亡作用,而Bcl-2抑制生精细胞凋亡的作用增强。
甘肃省居民不同年份死亡状况比较分析
王晓辉,刘玉琴,王晓莉,,张小栋
中国公共卫生 , 2009, DOI: 10.11847/zgggws2009-25-07-50
Abstract: ?人口死亡率及死亡原因分析是研究人群健康状况不可缺少的重要内容,是衡量社会经济发展水平和卫生状况的客观综合指标.为了解不同年份甘肃省居民死亡谱的变化趋势,研究其变化规律,为预测疾病未来发展、发生状况提供资料,对甘肃省1970-1974,1990-1992及2004-2005年死因回顾抽样调查资料进行分析.结果报告如下.
引大灌区玉米套种花椰菜滴灌高效栽培技术
,王海鹏,汪玉萍, 明
北方园艺 , 2010, DOI: 10.11937/bfyy.201009027
Abstract:
非结构化文本数据的gis描述性查询方法
海霞*,李佳田,李锐,,王华
计算机应用 , 2012,
Abstract: ?针对传统地理信息系统(gis)结构化或半结构化属性查询方法对查询语句输入的精度及查询范围的限制,提出了以哈尔滨工业大学《同义词词林》扩展版文本相关度计算为核心的非结构化文本数据gis描述性查询方法。基本过程是根据描述性查询语句计算其与地理要素所关联的文本的相关度,进而以相关度值得出概括性查询结果。对比实验结果表明,描述性查询方法不但支持查询语句输入的多样化,而且能够有效地得出与输入的描述性查询相关联的地理要素。
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