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对正项级数敛散性判别方法的研究 预览
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作者 李卫平 纪宏伟 《高等数学研究》 2019年第3期21-25,28共6页
利用函数的泰勒展开及极限的运算性质,借助已知敛散性的级数∑ 1/ n ( ln n) r 和∑ 1 /n( ln n)( ln ln n) r ,推出了判别正项级数敛散性的两个方法,并在此基础上得到了通项递减的正项级数敛散性的两个判别法.文中的结论强于双比值判别法.
关键词 正项级数 通项递减的正项级数 敛散性判别法
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A Generalized Propagator Algorithm for Localization of Non-circular Sources Using Arbitrary Array Geometry 预览
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作者 CAO Renzheng ZHANG Xiaofei 《南京航空航天大学学报:英文版》 EI CSCD 2019年第2期339-351,共13页
A propagator-based algorithm for direction of arrival(DOA)estimation of noncoherent one-dimensional(1-D)non-circular sources is presented such as binary phase shift keying(BPSK)and amplitude modulation(AM).The algorit... A propagator-based algorithm for direction of arrival(DOA)estimation of noncoherent one-dimensional(1-D)non-circular sources is presented such as binary phase shift keying(BPSK)and amplitude modulation(AM).The algorithm achieves DOA estimation through searching a 1-D spectrum,which is newly formed on the basis of the rank reduction criterion,and works well without knowledge of the non-circular phases.And then,a search-free implementation of the algorithm is also developed by using the polynomial rooting technique.According to the non-circular property,the algorithm can virtually enlarge the array aperture,thus significantly improving its estimation accuracy and enabling it to handle more sources than the number of sensors.Moreover,the algorithm requires no rotational invariance,so it can be applied to arbitrary array geometry and dispense with the high-complexity procedure of the eigen-decomposition of the correlation sample matrix.Finally,numerical simulations verify the performance and effectiveness of the proposed algorithm. 展开更多
关键词 direction of arrival(DOA) SUBSPACE method RANK reduction criterion PROPAGATOR NON-CIRCULAR source
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高地应力下硬岩V型破坏坑数值模拟研究
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作者 王媛 李宏璧 +1 位作者 张东明 张超锋 《水电能源科学》 北大核心 2019年第6期124-127,共4页
为确定可准确模拟高地应力下硬脆性岩体破坏的本构模型,以Mine-by试验隧道为例,采用线弹性模型、理想弹塑性模型、m-0准则、CWFS模型等4种常用的本构模型对高地应力下硬岩脆性破坏的一种典型破坏模式——V型破坏坑进行数值模拟。结果表... 为确定可准确模拟高地应力下硬脆性岩体破坏的本构模型,以Mine-by试验隧道为例,采用线弹性模型、理想弹塑性模型、m-0准则、CWFS模型等4种常用的本构模型对高地应力下硬岩脆性破坏的一种典型破坏模式——V型破坏坑进行数值模拟。结果表明,线弹性模型无法模拟硬岩的脆性破坏问题,仅可通过分析洞周围岩的二次应力场及强度系数分布特征粗略估计围岩张拉破坏范围;MOHR-COULOMB强度准则中不包含中间主应力σ2,无法考虑中间主应力对岩石强度的影响及岩体塑性屈服后的性能劣化,计算结果误差很大;可考虑围岩破坏过程中材料力学性能劣化的CWFS模型和m-0准则在模拟硬岩脆性破坏方面效果较好,数值结果与实际情形较为一致。研究结果可为类似工程开展岩爆破坏数值模拟和防治提供参考。 展开更多
关键词 Mine-by试验隧道 硬脆性岩体 V型破坏坑 摩尔库伦模型 应变软化模型 m-0准则
The HoekeBrown failure criterion and GSI-2018 edition 预览
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作者 E.Hoek E.T.Brown 《岩石力学与岩土工程学报:英文版》 CSCD 2019年第3期445-463,共19页
The HoekeBrown criterion was introduced in 1980 to provide input for the design of underground excavations in rock.The criterion now incorporates both intact rock and discontinuities,such as joints,characterized by th... The HoekeBrown criterion was introduced in 1980 to provide input for the design of underground excavations in rock.The criterion now incorporates both intact rock and discontinuities,such as joints,characterized by the geological strength index(GSI),into a system designed to estimate the mechanical behaviour of typical rock masses encountered in tunnels,slopes and foundations.The strength and deformation properties of intact rock,derived from laboratory tests,are reduced based on the properties of discontinuities in the rock mass.The nonlinear HoekeBrown criterion for rock masses is widely accepted and has been applied in many projects around the world.While,in general,it has been found to provide satisfactory estimates,there are several questions on the limits of its applicability and on the inaccuracies related to the quality of the input data.This paper introduces relatively few fundamental changes,but it does discuss many of the issues of utilization and presents case histories to demonstrate practical applications of the criterion and the GSI system. 展开更多
关键词 HOEK-BROWN criterion Geological STRENGTH index(GSI) ROCK MASS STRENGTH Uniaxial compressive strength(UCS) Tension cut-off ROCK MASS deformation modulus
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关于中医平行病历书写规范的建议
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作者 王昊 杨秋莉 +11 位作者 王子旭 杜渐 范逸品 商洪才 郭蓉娟 谢颖桢 孔军辉 张伯华 周荣新 贺苏 李春 王永炎 《现代中医临床》 2019年第3期6-10,共5页
叙事医学是医学人文实践的新形式,而其中平行病历为其实践的重要方式。中医学中没有叙事医学概念,但中医学具有浓厚的人文医学特性。中国中医科学院研究团队基于前期多项研究,通过在叙事医学实践过程中对不同年资医生进行访谈对话,以及... 叙事医学是医学人文实践的新形式,而其中平行病历为其实践的重要方式。中医学中没有叙事医学概念,但中医学具有浓厚的人文医学特性。中国中医科学院研究团队基于前期多项研究,通过在叙事医学实践过程中对不同年资医生进行访谈对话,以及中医平行病历的不断试写与实践探索,经过汇总专家意见并不断丰富与完善,最终形成了对中医平行病历书写规范的相关建议。内容主要包含中医平行病历的相关概念及书写目的、中医平行病历体裁形式与内容、中医平行病历书写流程、中医平行病历的分享、中医平行病历书写原则与注意事项以及中医平行病历访谈提纲等内容。在中医学临床实践中对中医平行病历的书写提出规范建议,更好地推动叙事医学理念方法在中医药领域的传播应用,促进和谐医患道德共同体的建立。 展开更多
关键词 叙事医学 平行病历 中医学 规范标准
Revisiting rock classification to estimate rock mass properties 预览
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作者 Robert Bertuzzi 《岩石力学与岩土工程学报:英文版》 CSCD 2019年第3期494-510,共17页
This paper presents the results of ongoing research carried out by the author exploring methods to provide a more robust estimate of rock mass properties specifically for use in tunnel design.Data from various large-s... This paper presents the results of ongoing research carried out by the author exploring methods to provide a more robust estimate of rock mass properties specifically for use in tunnel design.Data from various large-scale rock mass failures are introduced,including coal pillars.The damage-initiation,spalling-limit approach is compared to the coal pillar database.New comparisons of estimating the geological strength index(GSI)and relationships to estimate the Hoek-Brown failure criterion parameters,mb,s and a,are presented. 展开更多
关键词 ROCK mass PROPERTIES HoekeBrown STRENGTH criterion Geological STRENGTH index(GSI) TUNNELLING
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一元弱酸溶液氢离子浓度近似计算的课程新设计
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作者 林道广 王海水 《化学通报》 CAS CSCD 北大核心 2019年第6期563-565,533共4页
通常情况下,一元弱酸HA溶液氢离子浓度可按近似式[H^+]AV1=1/2(-Ka+√Ka^2+4cKa)或[H^2]AV2=√cKa估算。不同于现有教科书,本文以新的方式导出上述公式,并用数学方法推导出了[H^+]AV1和[H^+]AV2近似式的使用条件。(1)溶液中[H^+]■[OH^-... 通常情况下,一元弱酸HA溶液氢离子浓度可按近似式[H^+]AV1=1/2(-Ka+√Ka^2+4cKa)或[H^2]AV2=√cKa估算。不同于现有教科书,本文以新的方式导出上述公式,并用数学方法推导出了[H^+]AV1和[H^+]AV2近似式的使用条件。(1)溶液中[H^+]■[OH^-]时,可忽略水的离解,此时可用[H^+]AV1估算溶液pH。[H^+]AV1与氢离子准确浓度[H^+]T相对误差不大于±5%时,需要满足两条件c>6.0×10^-6mol·L^-1和c Ka≥10Kw;(2)用[H^+]AV2估算溶液pH的条件为[H^+]■[OH^-]和[HA]≈c,即同时忽略水的离解和忽略HA的离解。[H^+]AV2与[H^+]T相对误差不大于±5%时,要求满足c Ka≥10Kw和c≥105Ka。本文首次用数学方法推导出c Ka≥10Kw或c≥105Ka等条件,与现教科书有关内容比较,具有判据严谨、边界条件清晰、学生容易理解等优点,对提高教学效果具有积极意义。 展开更多
关键词 一元弱酸 氢离子浓度 近似式 判据
Fracture Analysis of Cast Iron Materials with Cracks Based on Elastoplastic Extended Finite Element Method
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作者 Yanjun Chang Qiao Song +2 位作者 Zheng Kuang Keshi Zhang Zhanguang Zheng 《固体力学学报:英文版》 SCIE EI CSCD 2019年第2期201-214,共14页
Based on the ABAQUS platform for finite element analysis, the extended finite element method (XFEM) considering elastoplastic constitutive relationship is developed, by which the displacement discontinuity across the ... Based on the ABAQUS platform for finite element analysis, the extended finite element method (XFEM) considering elastoplastic constitutive relationship is developed, by which the displacement discontinuity across the crack surface and the strong nonlinearity near the crack tip can be described more accurately. The strip specimens with unilateral cracks and central cracks under uniaxial tension are simulated using the XFEM and the FEM, respectively. The J-integral across the crack on each incremen t is calcula ted using the equivale nt domain integral met hod (EDIM), the interaction integral met hod and the FEM, respectively. The effec ts of mesh size and mesh shape near the crack tip, element type and different calculation methods on the accuracy of J-integral are analyzed. The simulation results show that the XFEM is more accurate than the FEM with the same element size and type. The fracture tests of cast iron specimens with unilateral cracks under uniaxial tension are performed, and the J-integral criterion is valid to predict the fracture initiation in numerical simulation. The critical value of J-integral is calculated using the EDIM of the XFEM. The comparisons demonstrate that the simulated elastoplastic load-displacement curves with the XFEM are in good agreement with the experimental results. 展开更多
关键词 J-INTEGRAL Extended FINITE element Elastoplasticity FRACTURE CRITERION
A case study of a Kuroshio main path cut-off event and impacts on the South China Sea in fall-winter 2013–2014 预览
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作者 Quanan Zheng Chung-Ru Ho +1 位作者 Lingling Xie Mingming Li 《海洋学报:英文版》 SCIE CAS CSCD 2019年第4期12-19,共8页
This study examines a Kuroshio main path(KMP)cut-off event east of Taiwan Island occurred in fall-winter 2013–2014 and its impacts on the South China Sea(SCS)by analyzing satellite altimetry and mooring observations.... This study examines a Kuroshio main path(KMP)cut-off event east of Taiwan Island occurred in fall-winter 2013–2014 and its impacts on the South China Sea(SCS)by analyzing satellite altimetry and mooring observations.Satellite altimeter sea level anomaly(SLA)images reveal a complete process that a huge cyclonic eddy(CE)from the Pacific collided with the Kuroshio and the western boundary from 15 October 2013 to 15 January 2014.Mooring observations evidenced that the Kuroshio upper ocean volume transport was cut off more than 82%from 17×10^6 m^3/s in September to 3×10^6 m^3/s in November 2013.The KMP cut-off event caused the Kuroshio branching and intruding into the SCS and strengthened the eddy kinetic energy in the northern SCS west of the Luzon Strait.Using the total momentum as a dynamic criterion to determine the role of eddy collision with the Kuroshio reasonably explains the KMP cut-off event. 展开更多
关键词 KMP CUT-OFF EVENT EDDY kinetic energy dynamic criterion South China Sea
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基于弹性应变能的钢筋混凝土简支梁极限承载力判据研究
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作者 夏雨 胡淼珍 +1 位作者 聂宏涛 张泽俊 《应用力学学报》 CAS CSCD 北大核心 2019年第2期485-491,517-518共8页
基于弹性应变能提出了钢筋混凝土简支梁极限承载力的能量判别依据。首先对简支梁进行了有限元建模计算;然后对简支梁9种工况下的混凝土单元弹性应变能进行了概率统计分析,由加载过程中弹性应变能的概率分布形式及变化情况来分析混凝土... 基于弹性应变能提出了钢筋混凝土简支梁极限承载力的能量判别依据。首先对简支梁进行了有限元建模计算;然后对简支梁9种工况下的混凝土单元弹性应变能进行了概率统计分析,由加载过程中弹性应变能的概率分布形式及变化情况来分析混凝土单元的破坏,从整体趋势上计算极限承载力,降低了数值计算时的误差。研究发现:混凝土单元应变能符合对数正态分布,且随着加载过程逐渐趋于稳定,较客观地反映了构件变形过程中能量积累的特征;应变能对数正态分布拟合参数的变化较符合二次曲线,由二次曲线方程能够推断出构件所能承受的极限荷载,与理论值相比有较高的一致性,其误差为13.6%,且此误差可通过改进模型得到控制。文中所提的判据可为极限承载力判据的研究提供参考。 展开更多
关键词 钢筋混凝土简支梁 弹性应变能 概率分布 极限承载力 判据
EM算法的参数分辨率 预览
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作者 鲁纳纳 余旌胡 《数学物理学报:A辑》 CSCD 北大核心 2019年第3期638-648,共11页
参数分辨率是在给定噪声情况下,衡量两个相近信号能否区分开的一个标准,为敏感参数、有效精度以及准确度的衡量提供了评估的"尺子".该文以EM算法为基础,结合Fisher线性判别准则的思想,给出EM算法参数分辨率的定义,并以两正态... 参数分辨率是在给定噪声情况下,衡量两个相近信号能否区分开的一个标准,为敏感参数、有效精度以及准确度的衡量提供了评估的"尺子".该文以EM算法为基础,结合Fisher线性判别准则的思想,给出EM算法参数分辨率的定义,并以两正态混合模型为例进行验证.实验表明两个方差为0.1的正态分布其均值距离大于0.206时,EM算法在90%的置信度下可以区分这两个分布,通过构建实验结果和理论推导之间的联系,得到不同置信度下的比例因子图.参数分辨率的提出,为准确度的衡量提供一个定量指标,也为相近信号的区分提供新的解决方案. 展开更多
关键词 EM算法 分辨率 判别准则 变异系数
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An Iterative Compensation Algorithm for Springback Control in Plane Deformation and Its Application
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作者 Rui Ma Chunge Wang +1 位作者 Ruixue Zhai Jun Zhao 《中国机械工程学报:英文版》 SCIE EI CAS CSCD 2019年第2期212-223,共12页
In order to solve the springback problem in sheet metal forming, the trial and error method is a widely used method in the factory, which is time-consuming and costly for its non-direction and non-quantitative. Finite... In order to solve the springback problem in sheet metal forming, the trial and error method is a widely used method in the factory, which is time-consuming and costly for its non-direction and non-quantitative. Finite element simulation is an e ective method to predict the springback of complex shape parts, but its precision is sensitive to the simulation model, particularly material model and boundary conditions. In this paper, the simple iterative method is introduced to establish the iterative compensation algorithm, and the convergence criterion of iterative parameters is put forward. In addition, the new algorithm is applied to the V-free bending and stretch-bending processes, and the convergence of curvature and bending angle is proved theoretically and verified experimentally. At the same time,the iterative compensation experiments for plane bending show that, the new method can predict the next compensaantido tnh ev atlaureg ebta cseurdv oatnu trhe ew sitphri tnhgeb earcrko ro fo fe laecshs ttehsat,n s0 o. 5 th%a ta rteh eo btatraigneet db aefntedri n2 g-3 a nitgelrea tiwoitnhs.t Thhei se rrreosre aorf clhe sps rtohpaons e±s 0 a.1%new iterative compensation algorithm to predict springback in sheet metal forming process, where each compensation value depends only on the iteration parameter di erence before and after springback for the same forming process of same material. 展开更多
关键词 SPRINGBACK control ITERATIVE COMPENSATION algorithm CONVERGENCE CRITERION V-free BENDING Stretchbending
Slope reliability and back analysis of failure with geotechnical parameters estimated using Bayesian inference 预览
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作者 Luis-Fernando Contreras Edwin T.Brown 《岩石力学与岩土工程学报:英文版》 CSCD 2019年第3期628-643,共16页
A Bayesian approach is proposed for the inference of the geotechnical parameters used in slope design.The methodology involves the construction of posterior probability distributions that combine prior information on ... A Bayesian approach is proposed for the inference of the geotechnical parameters used in slope design.The methodology involves the construction of posterior probability distributions that combine prior information on the parameter values with typical data from laboratory tests and site investigations used in design.The posterior distributions are often complex,multidimensional functions whose analysis requires the use of Markov chain Monte Carlo(MCMC)methods.These procedures are used to draw representative samples of the parameters investigated,providing information on their best estimate values,variability and correlations.The paper describes the methodology to define the posterior distributions of the input parameters for slope design and the use of these results for evaluation of the reliability of a slope with the first order reliability method(FORM).The reliability analysis corresponds to a forward stability analysis of the slope where the factor of safety(FS)is calculated with a surrogate model from the more likely values of the input parameters.The Bayesian model is also used to update the estimation of the input parameters based on the back analysis of slope failure.In this case,the condition FS?1 is treated as a data point that is compared with the model prediction of FS.The analysis requires a sufficient number of observations of failure to outbalance the effect of the initial input parameters.The parameters are updated according to their uncertainty,which is determined by the amount of data supporting them.The methodology is illustrated with an example of a rock slope characterised with a Hoek-Brown rock mass strength.The example is used to highlight the advantages of using Bayesian methods for the slope reliability analysis and to show the effects of data support on the results of the updating process from back analysis of failure. 展开更多
关键词 BAYESIAN ANALYSIS HOEK-BROWN CRITERION SLOPE reliability Back ANALYSIS of FAILURE
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Rock mechanics for design of Brisbane tunnels and implications of recent thinking in relation to rock mass strength 预览
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作者 L.B.McQueen A.Purwodihardjo S.V.L.Barrett 《岩石力学与岩土工程学报:英文版》 CSCD 2019年第3期676-683,共8页
This paper explores the potential implications of recent thinking in relation to rock mass strength for future tunnelling projects in Brisbane,Australia,particularly as they are constructed within deep horizons where ... This paper explores the potential implications of recent thinking in relation to rock mass strength for future tunnelling projects in Brisbane,Australia,particularly as they are constructed within deep horizons where the in situ stress magnitudes is larger.Rock mass failure mechanisms for the current tunnels in Brisbane are generally discontinuity controlled and the potential for stress-induced failure is relatively rare.For the road tunnels which have been constructed in Brisbane over the last 12 years,the strength of the more massive rock masses for continuum analysis has been estimated by the application of the Hoek-Brown(H-B)failure criterion using the geological strength index(GSI)to determine the H-B parameters mb,s and a.Over the last few years,alternative approaches to estimating rock mass strength for‘massive to moderately jointed hard rock masses’have been proposed by others,which are built on the work completed by E.Hoek and E.T.Brown in this area over their joint careers.This paper explores one of these alternative approaches to estimating rock mass strength for one of the geological units(the Brisbane Tuff),which is often encountered in tunnelling projects in Brisbane.The potential implications of these strength forecasts for future tunnelling projects are discussed along with the additional work which will need to be undertaken to confirm the applicability of such alternative strength criteria for this rock mass. 展开更多
关键词 Rock mass strength Hoek-Brown(H-B)failure criterion Triaxial testing BRITTLE FAILURE BRISBANE TUFF
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Existence criteria and validity of plate models for graphene-like materials
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作者 JiaPeng Chen Biao Wang 《中国科学:物理学、力学、天文学英文版》 SCIE EI CAS CSCD 2019年第5期84-98,共15页
Graphene-like(GL) materials have enriched the application prospects of two-dimensional materials by virtue of their various structures and properties. However, the following theoretical issues remain unsolved: how can... Graphene-like(GL) materials have enriched the application prospects of two-dimensional materials by virtue of their various structures and properties. However, the following theoretical issues remain unsolved: how can stable GL materials exist and is plate idealization valid for any GL materials? Here we answer these questions based on an atomistic potential-based approach.The existence criteria for GL materials with three common structures, including planar honeycomb(PH), buckled honeycomb(BH), and honeycomb MX2(2 H-MX2) structures, were established. Moreover, the validity of classic linear-elastic plate models for these materials was examined. A validity factor, which represents the validity of using thin plate models to investigate the overall mechanical response of GL sheets, was defined. We determined that 2 H-MX2 sheets can approximately be modeled as thin plates for arbitrary loadings, unlike PH and BH sheets. 展开更多
关键词 grapheme-like material EXISTENCE CRITERION plate IDEALIZATION
大坝可接受风险水平确定方法研究
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作者 王丽萍 李宁宁 +2 位作者 马皓宇 张验科 纪昌明 《水力发电学报》 CSCD 北大核心 2019年第4期136-145,共10页
F-N曲线法是一种通过直观图解描述风险频率(F)与后果(N)间关系的曲线,常与最低合理可行(as low as reasonably practicable,ALARP)准则相结合来确定社会风险可接受水平。现行方法中存在参数的确定缺乏理论依据、主观性强,且对于不同地... F-N曲线法是一种通过直观图解描述风险频率(F)与后果(N)间关系的曲线,常与最低合理可行(as low as reasonably practicable,ALARP)准则相结合来确定社会风险可接受水平。现行方法中存在参数的确定缺乏理论依据、主观性强,且对于不同地区、不同风险类别通用性差等问题。本文针对上述问题提出了融合风险矩阵的改进F-N曲线。通过风险矩阵有效衔接现有风险规范,并提出了风险单元等级划分定性与定量相结合的方法,基于此将风险矩阵转化为F-N曲线。在大坝可接受风险水平研究的基础上,阐述了该方法的具体实现过程,并对比分析了与传统方法的差异和联系,比较结果说明改进后的F-N曲线较传统曲线更加规范、合理,且易于推广应用到其他类型的风险研究与计算中。 展开更多
关键词 大坝风险 风险频率-后果曲线 风险矩阵 可接受水平 规范
基于MIRPSA的感应电动机转子断条数目诊断判据
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作者 许伯强 孙丽玲 《电力自动化设备》 EI CSCD 北大核心 2019年第3期132-136,共5页
在感应电动机转子断条数目诊断方面,电机定子电流信号分析(MCSA)类方法已经建立明确的解析判据,而电机瞬时无功功率信号分析(MIRPSA)类方法缺乏理论支撑。为此,针对转子断条故障推导了感应电动机瞬时无功功率特征分量的幅值与转子断条... 在感应电动机转子断条数目诊断方面,电机定子电流信号分析(MCSA)类方法已经建立明确的解析判据,而电机瞬时无功功率信号分析(MIRPSA)类方法缺乏理论支撑。为此,针对转子断条故障推导了感应电动机瞬时无功功率特征分量的幅值与转子断条数目间的数值对应关系,由此建立了具有解析意义的基于MIRPSA的转子断条数目诊断判据。感应电动机转子断条故障仿真与实验证明了所提判据的有效性。 展开更多
关键词 感应电动机 转子断条 故障诊断 判据 电机定子电流信号分析 电机瞬时无功功率信号分析
《蛔虫病诊断》(WS/565-2017)解读
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作者 臧炜 陈颖丹 +2 位作者 朱慧慧 郑彬 周长海 《中国血吸虫病防治杂志》 CAS CSCD 北大核心 2019年第2期207-209,共3页
蛔虫病曾是我国农村地区的常见病之一,尽管其流行程度较21世纪初已大幅减轻,但仍然广泛存在。2015年全国人体重点寄生虫病现状调查显示,我国人群蛔虫平均感染率为1.36%。原国家卫生和计划生育委员会于2017年8月1日颁布实施了《蛔虫病诊... 蛔虫病曾是我国农村地区的常见病之一,尽管其流行程度较21世纪初已大幅减轻,但仍然广泛存在。2015年全国人体重点寄生虫病现状调查显示,我国人群蛔虫平均感染率为1.36%。原国家卫生和计划生育委员会于2017年8月1日颁布实施了《蛔虫病诊断》(WS/565-2017)标准。该标准由6章组成,包括适用范围、术语和定义、诊断依据、诊断原则、诊断标准和鉴别诊断,另附有4个资料性附录(病原学、流行病学、临床表现及鉴别诊断)和1个规范性附录(病原学检查)。该标准的颁布施行,为全国各级医疗机构和疾病预防控制机构诊断蛔虫病提供了技术规范。本文结合我国蛔虫病流行情况,对《蛔虫病诊断》(WS/565-2017)标准的主要内容进行了解读,以促进该标准的宣传贯彻和实施。 展开更多
关键词 蛔虫病 诊断 标准
Heat transfer performance for DCLL blanket with no-wetting insulator walls 预览
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作者 Hulin Huang Shimou Yin Guiping Zhu 《力学快报:英文版》 CAS CSCD 2019年第3期195-201,共7页
Magnetohydrodynamic (MHD) effect and heat transfer are two key issues for design of dual coolant lead lithium (DCLL) blanket. Flow channel insert (FCI) has been applied to decouple the liquid metal from the walls to e... Magnetohydrodynamic (MHD) effect and heat transfer are two key issues for design of dual coolant lead lithium (DCLL) blanket. Flow channel insert (FCI) has been applied to decouple the liquid metal from the walls to efficiently decline MHD pressure drops and reduce heat losses from the liquid metal for increasing bulk exit temperatures of the blanket. However, there are still big pressure drops and a higher velocity jet located at the gap flow. Moreover, the FCI made from silicon carbide (SiC) constitutes a complex blanket structures which potentially causes special flow phenomena. In the present work, the characteristics of fluid flow and heat transfer in the DCLL blanket channel are investigated for the first wall (FW) sprayed a layer of no-wetting nano coating (NWNC) on its inner surface. The results show that the pressure drop with NWNC wall is oneorder magnitude lower than that with FCI in the general DCLL blanket. The Nusselt number on the NWNC wall is about half of that on the general wall. On this basis, a heat transfer criterion equation of DCLL channel is achieved for the NWNC wall without FCI. The results are compared with that criterion equation of general wall conditions, which indicates the criterion equation can well predict the convection heat transfer of DCLL channel. 展开更多
关键词 CONVECTION heat transfer Nano coating wall COMPUTATIONAL fluid dynamics MAGNETOHYDRODYNAMIC effect Criterion equation
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一项优化AJCC/UICC pTNM胃癌分期预后预测效能的多中心研究 预览
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作者 Cheng Fang Wei Wang +6 位作者 Jing-Yu Deng Zhe Sun Sharvesh Raj Seeruttun Zhen-Ning Wang Hui-Mian Xu Han Liang Zhi-Wei Zhou 《癌症》 SCIE CAS CSCD 2019年第4期187-198,共12页
背景与目的美国癌症联合会与国际抗癌联盟(AmericanJointCommitteeonCancer/UnionforInternationalCancerControl,A JCC/UICC)联合发布的第8版TNM病理分期(pathological tumor?node?metastasis,p TNM)较前进行了重要修改,以提高胃癌患... 背景与目的美国癌症联合会与国际抗癌联盟(AmericanJointCommitteeonCancer/UnionforInternationalCancerControl,A JCC/UICC)联合发布的第8版TNM病理分期(pathological tumor?node?metastasis,p TNM)较前进行了重要修改,以提高胃癌患者预后预测准确性。然而,该分期不同亚组间患者的预后仍存在一定的同质性。本研究旨在对比第8版和第7版AJCC/UICC pTNM分期对胃癌预后的预测效能,并纳入外部验证对现有分期进行优化。方法共纳入分析7911例就诊于中国3家大型医疗中心和10,208例美国流行病监测与最终治疗结果(Surveillance Epidemiology and End Results,SEER)数据库的患者临床资料。采用log-rank检验、线性趋势检验、似然比检验和赤池信息量准则(akaike information criterion,AIC)梯度评估第7、8版AJCC/UICC pTNM分期系统的同质性、辨别力和单调性,在此基础上优化分期并以SEER数据集作为外部验证。结果第7、8版分期系统在两组数据集中均存在明显分期偏移,且集中在III期患者。IIIA、IIIB和IIIC期各亚组内患者的生存率有显著差异,表明两个系统分期分层的同质性较差。我们根据中国患者数据构建一个新的改良版p TNM分期,上述分层同质性问题得到明显改善,进一步以SEER数据作为验证集同样得到了良好的结果。相较第7、8版分期系统,改良版p TNM分期在两组数据集中均有较高的log-rank、线性趋势、似然比卡方值和较低的AIC值,显示出更优的辨别力、同质性、单调性和预后预测效能。结论第8版AJCC/UICC pTNM分期系统优于第7版,但预后预测的同质性均较差。我们构建的改良版p TNM分期在两组大样本胃癌数据集中均显示出理想的分期分层和预后预测效能。 展开更多
关键词 TNM病理分期系统 胃癌 赤池信息准则(akaike information criterion AIC) 预后预测 SEER 中国人
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