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On the Analysis Method of the Triple Test Cross Design
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作者 Jin Yi(Northeast Agricultural University, Harbin 1 50030, P R C) 《Journal of Northeast Agricultural University(English Edition)》 CAS 1995年第1期66-74,共9页
The analysis method of the triple test cross design has been discussed carefully from the two factor experiment design and the genetic models of additive dominant effect and of epistasis effect.Two points different f... The analysis method of the triple test cross design has been discussed carefully from the two factor experiment design and the genetic models of additive dominant effect and of epistasis effect.Two points different from the previous reports have been concluded: (1)both the degrees of freedom of the orthogonal terms C2 and C3 are m, (2)the denominator in the F test to C2 and C3 is the error mean of square between plots. 展开更多
关键词 Triple test cross design Additive-dominant model Epistasis model Genetic parameter estimate.
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Research and application of cross-test strategy based on component
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作者 SONG Yu TIAN Hua CAO Yong-feng 《通讯和计算机(中英文版)》 2007年第8期40-43,共4页
关键词 交叉测试策略 软件测试 组成 应用 软件开发
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Study of Neutron Cross Talk Rejection Based on Testing Experiment and Simulation
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作者 游海波 宋玉收 +1 位作者 肖军 叶沿林 《Plasma Science and Technology》 SCIE EI CAS CSCD 2012年第6期473-477,共5页
Experimental data analysis and simulation calculations were performed in order to evaluate the cross-talk rejection performance of a typical neutron detection array. For very closely packed scintillation bars, the CT ... Experimental data analysis and simulation calculations were performed in order to evaluate the cross-talk rejection performance of a typical neutron detection array. For very closely packed scintillation bars, the CT rejection may rely on the position relation between the two signals. The criteria |△x|≤ 15 cm and |△y|≤12 cm are currently proposed for a rejection rate higher than 90%. For signals coming from distanced bars, the energy conservation relationship can be applied to reject the CT events with a similar performance. In both cases the results of simulation agree very well with the experimental data, assuring their applicability to other detection systems and physics problems. 展开更多
关键词 test experiment GEANT4 simulation cross talk neutron detection
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The “Colour Family Drawing Test”: Assessing Children’s Perception of Family Relationships. Studies on Mental Health and Cross-Cultural Comparisons
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作者 Valeria Biasi Paolo Bonaiuto James M. Levin 《Health》 2015年第3期300-307,共8页
We apply the Colour Family Drawing Test, as a development of the traditional black and white test, for cross-cultural comparison. The participants, aged 7 - 10 years, both genders, were examined individually. Each sub... We apply the Colour Family Drawing Test, as a development of the traditional black and white test, for cross-cultural comparison. The participants, aged 7 - 10 years, both genders, were examined individually. Each subject sat at a single table with a white rectangular card of standard size, 24 well-sharpened colour pencils, a black pencil, an eraser and other appropriate tools. S/he received this verbal instruction: “Draw your family”. The procedure was firstly applied to 120 participants attending primary schools of Rome (Biasi, Bonaiuto and Levin, 2014). The families were evaluated through a semi-structural interview conducted with the children’s teachers and divided into: Harmonious versus Very Conflictual Families. The drawings made by children of Harmonious Families consistently used “Reassuring and Playful Colours” (Pink, Orange, Sky Blue, Light Green, Light Yellow, other pastel colours);and were larger, tidier and more proportioned to respect the opposite group. Children belonging to Conflictual Families used mostly “Alarming and Serious Colours” (Grey, Black, Dark Bleu, Violet, Olive Green) and their drawings were less extended, more often disordered and had typical deformations such as figures too thin. A second investigation examined 120 participants belonging to Asian immigrant families residing in Italy. A third investigation examined 120 participants belonging to Russian families of Moscow. Both last two investigations obtained very similar results on the use of colours, and gave a confirmation of the relevance of the Colour Family Drawing Test. 展开更多
关键词 COLOUR Conflictual FAMILY cross-Cultural Comparison COLOUR DRAWING FAMILY test EXPRESSIVENESS
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Testing for Cross-Sectional Dependence in a RandomEffects Model
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作者 Afees Salisu Sam Olofin Eugene Kouassi 《Open Journal of Statistics》 2012年第1期88-97,共10页
This paper extends and generalizes the works of [1,2] to allow for cross-sectional dependence in the context of a two-way error components model and consequently develops LM test. The cross-sectional dependence follow... This paper extends and generalizes the works of [1,2] to allow for cross-sectional dependence in the context of a two-way error components model and consequently develops LM test. The cross-sectional dependence follows the first order spatial autoregressive error (SAE) process and is imposed on the remainder disturbances. It is important to note that this paper does not consider alternative forms of spatial lag dependence other than SAE. It also does not allow for endogeneity of the regressors and requires the normality assumption to derive the LM test. 展开更多
关键词 cross-SECTIONAL DEPENDENCE Error Components MODEL LAGRANGIAN MULTIPLIER (LM) tests
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Characteristics of the Variation of Cross Fault Short-Baseline and Short-Range Leveling in Western Yunnan Earthquake Test Site Before Lijiang M_S7.0 Earthquake
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作者 Li Zhonghua, Su Youjing, and Liu ZhuyinSeismological Bureau of Yunnan Province, Kunming 650041, China 《Earthquake Research in China》 1998年第4期46-56,共11页
Results of analysis of variation of cross fault short-baseline and short-range leveling in Western Yunnan Earthquake Test Site (WYETS), results show that among five observation stations of cross fault short-baseline a... Results of analysis of variation of cross fault short-baseline and short-range leveling in Western Yunnan Earthquake Test Site (WYETS), results show that among five observation stations of cross fault short-baseline and short-range leveling in WYETS before the Lijiang MS7.0 Earthquake occurred in February 1996 only Yongsheng observation station (epicentral distance 82 km) located at Chenghai fault shows great variation about one year before the earthquake. And the nearest observation station, Lijiang (epicentral distance 42 km); presents great coseismic variation, but does not show obvious anomalous variation before the earthquake. There are no significant variations related to the earthquake at the other three observation stations. Two methods are used in analysis of the observed data and some valuable results have been obtained. 展开更多
关键词 cross FAULT measurement Lijiang MS7.0 EARTHQUAKE Western Yunnan EARTHQUAKE test Site.
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线性规划的无比值检验criss-cross算法 被引量:2
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作者 颜红彦 潘平奇 《合肥工业大学学报(自然科学版)》 CAS CSCD 北大核心 2009年第12期1949-1952,共4页
Zionts提出的求解线性规划问题的criss-cross算法实际是一阶段算法,不过与传统一阶段算法不同,它交替进行原始和对偶迭代,而产生的既可以是原始可行解,也可以是对偶可行解。为了提高计算效率,文章提出了一种采用无比值检验规则的新criss... Zionts提出的求解线性规划问题的criss-cross算法实际是一阶段算法,不过与传统一阶段算法不同,它交替进行原始和对偶迭代,而产生的既可以是原始可行解,也可以是对偶可行解。为了提高计算效率,文章提出了一种采用无比值检验规则的新criss-cross算法,基于新算法编制的一个稠密软件在对40个小问题进行的数值试验中,就迭代次数而言,以2.12的比率胜过了传统的两阶段算法。 展开更多
关键词 线性规划 criss—cross算法 无比值检验规则
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USING CROSS-CORRELATION THEORY TO EXTRACT MODAL PARAMETERS IN FREQUENCY- DOMAIN 被引量:1
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作者 ShenFan ZhengMin 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2003年第1期83-86,共4页
Conventional modal parameter identifications are usually based on frequencyresponse functions, which require measurements of both the input force and the resulting response.However, in many cases, only response data a... Conventional modal parameter identifications are usually based on frequencyresponse functions, which require measurements of both the input force and the resulting response.However, in many cases, only response data are available while the actual excitations (such aswind/wave load) are not measurable. Modal parameters estimation must base itself on response-onlydata. Over the past years, many time-domain modal parameter identification techniques fromoutput-only are proposed. A poly-reference frequency-domain modal identification scheme onresponse-only is presented. It is based on coupling the cross-correlation theory with conventionalfrequency-domain modal parameter extraction. An experiment using an airplane model is performed toverify the proposed method. 展开更多
关键词 Modal identification Vibration testing cross-correlation theory Operating conditions
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The Trail Making Test in Morocco: Normative Data Stratified by Age and Level of Education 被引量:1
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作者 Asmaa Oumellal Mustapha El Alaoui Faris Maria Benabdeljlil 《Open Journal of Medical Psychology》 2018年第1期1-12,共12页
The purpose of this study is to design a Moroccan Trail Making Test B;explore the effects of age, education and gender on the performance of the Trail Making Test (TMT);and provide normative information in Moroccan su... The purpose of this study is to design a Moroccan Trail Making Test B;explore the effects of age, education and gender on the performance of the Trail Making Test (TMT);and provide normative information in Moroccan subjects. Our normalization study was conducted on 348 subjects (156 female and 192 male). The subjects were classified into four groups based on age (18 - 39 years, 40 - 59 years, 60 - 69 years and ≥70 years), and three groups based on educational level (3 - 6 years, 7 - 10 years and ≥11 years). The data were analyzed using descriptive statistics through SPSS. The results displayed that increasing age and decreasing levels of education significantly result in a decreased performance on the Trail A, Moroccan Trail B and English Trail B. Only 229 bilingual subjects among the 348 initial subjects completed both versions of Trail B. There was no significant difference on performance between Moroccan Trail B and English Trail B for these subjects. 展开更多
关键词 TRAIL MAKING test in Morocco cross-CULTURAL NEUROPSYCHOLOGY NORMATIVE Data
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CONTOUR DESIGN AND PRACTICE FOR A LOW RADAR CROSS SECTION VEHICLE
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作者 Zhang Zhongan Wang Lue(Research Institute of Pilotless Aircraft, Nanjing University of Aeronautics and Astronautics, Nanjing, China, 210016) 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 1996年第1期43-47,共5页
On the basis of the canard configuration a contour stealth design including chiefly the wing, the fuselage and their connection type is projected. The prime project of a blended wing body vehicle with canard is provid... On the basis of the canard configuration a contour stealth design including chiefly the wing, the fuselage and their connection type is projected. The prime project of a blended wing body vehicle with canard is provided and through the change of the fuselage head form and the different fin disposals, the radar cross section (RCS) is optimized. The average value of RCS and the value of RCS in the ± 45 ° front sector for different designs are illustrated. The model measurement proves that the project having a sharp head fuselage and 30 ° angle double fin has the minimum value of RCS. The wind tunnel test to the model with RCS optimized proved that the vehicle project has excellent aerodynamic characteristics such as high lift curve slope, up to 26° stalling angle, high lift / drag ratio equal to 8, and also has low RCS value in the front sector and in the lateral sector. 展开更多
关键词 aircraft design electromagnetic scattering wind tunnel tests radar cross section
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Balloon test occlusion of internal carotid artery: Angiographic findings predictive of results
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作者 Kazufumi Kikuchi Takashi Yoshiura +3 位作者 Akio Hiwatashi Osamu Togao Koji Yamashita Hiroshi Honda 《World Journal of Radiology》 CAS 2014年第8期619-624,共6页
AIM: To reveal angiographic findings to predict the re-sult of balloon test occlusion(BTO).METHODS: The cerebral angiograms of 42 consecu-tive patients who underwent cerebral angiography in-cluding both the Matas and ... AIM: To reveal angiographic findings to predict the re-sult of balloon test occlusion(BTO).METHODS: The cerebral angiograms of 42 consecu-tive patients who underwent cerebral angiography in-cluding both the Matas and Allcock maneuvers and BTO were retrospectively analyzed. Visualization of the an-terior cerebral artery(ACA) and the middle cerebral ar-tery(MCA) by the cross flow on the tested side during the Matas or Allcock maneuver was graded on a 5-point scale. Circle of Willis(COW) anatomy with respect to the presence/absence of a collateral path to reach the tested internal carotid artery(ICA) was classified intofour categories. A univariate logistic analysis was used to analyze the associations between each angiographic finding and the BTO result. Sensitivity, specificity, accu-racy, positive predictive value, and negative predictive value for each finding were calculated. RESULTS: Five patients(12%) were BTO-positive and the remaining 37 patients(88%) were BTO-negative. Visualizations of the ACA and MCA as well as the COW anatomy were significantly associated with the BTO re-sult(P = 0.0051 for ACA, P = 0.0002 for MCA, and P < 0.0001 for COW anatomy). In particular, good MCA vi-sualization and the presence of an anterior connection(collateral path to the tested ICA from the contralateral ICA via the anterior communicating artery) in the COW were highly predictive for negative BTO(negative pre-dictive value = 100% for both). 展开更多
关键词 BALLOON test OCCLUSION cross flow Circle of WILLIS ANTERIOR CIRCULATION Posterior CIRCULATION
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Study on Various Compositions of Polyvinyl Alcohol and Starch Blends by Cross-Linking with Glyoxal 被引量:3
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作者 Ravindra V. Gadhave Prakash A. Mahanwar Pradeep T. Gadekar 《Open Journal of Polymer Chemistry》 2019年第4期76-85,共10页
The aim of this study is to analyze the various compositions of polyvinyl alcohol (PVA) and starch blends. The blends have been cross-linked with glyoxal to enhance its properties. The hydroxyl groups of PVA and starc... The aim of this study is to analyze the various compositions of polyvinyl alcohol (PVA) and starch blends. The blends have been cross-linked with glyoxal to enhance its properties. The hydroxyl groups of PVA and starch react with glyoxal via formation of acetal bonds;hence crosslinking could take place. The cross-linking of glyoxal is observed in various analytical methods such as DSC and FTIR. The cross-linked blends showed better thermal and mechanical properties. Viscosity, tensile shear strength, pencil hardness and ultimate stress were evaluated to estimate the changes due to cross-linking. It was observed that the cross-linking is directly proportional to starch, since the starch hydroxyl groups are easily accessible for reacting. The cross-linked blend showed better cohesion between its chains, thereby increasing glass transition temperature. It was reflected in the subsequent increase in tensile strength properties. 展开更多
关键词 STARCH Polyvinyl ALCOHOL cross-Linking GLYOXAL Mechanical testing
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Self-Cross-Linked Tannin-Aminated Tannin Surface Coatings for Particleboard
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作者 Bengang Zhang Antonio Pizzi +2 位作者 Mathieu Petrissans Anelie Petrissans Colin Baptiste 《Journal of Renewable Materials》 EI 2023年第12期4097-4121,共25页
Aminated tannins were prepared by reacting mimosa condensed tannin extract with ammonia yielding the substitution of many,if not all of the tannin hydroxyl groups with–NH_(2)groups.A tannin-aminated tannin(ATT)partic... Aminated tannins were prepared by reacting mimosa condensed tannin extract with ammonia yielding the substitution of many,if not all of the tannin hydroxyl groups with–NH_(2)groups.A tannin-aminated tannin(ATT)particleboard coating was then prepared by reacting raw tannin extract with aminated tannin extract and thus cross-linking the two by substituting tannin’s hydroxyl groups with the–NH_(2)groups on the aminated tannin to form–NH-bridges between the two.The resulting particleboard coating gave encouraging results when pressed at 180℃for 3 min.Conversely,the system in which tannin was reacted/cross-liked with urea(ATU)by a similar amination reaction did not perform as well as the ATT system,and this even when a higher curing temperature and longer hot press time were used.In particular its water repellence was worse probably due to the presence of urea and such a system with lower reactivity.Nonetheless,substituting the tannin–OHs with the urea–NH_(2)groups appeared to also take place.ATT gave better results than ATU as regards water repellence and mechanical resistance as shown by the cross cut test.The ATT system was shown to be between 95%and 98%biosourced.The difference appeared to be due,by TMA analysis,to the much faster formation of the ATT hardened network leading to a better cross-linked polymer coating.The chemical species formed for both the ATT and ATU system were studied by MALDI ToF and CP MAS^(13)C NMR. 展开更多
关键词 Biocoatings PARTICLEBOARD aminated tannin cross-linked tannin-aminated tannin tannin-urea cross links water repellence cross cut test MALDI ToF ^(13)C NMR
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一种基于函数依赖的跨合约模糊测试方案
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作者 张立强 路梦君 严飞 《信息网络安全》 CSCD 北大核心 2024年第7期1038-1049,共12页
随着区块链应用的快速发展和智能合约的广泛使用,由智能合约引发的安全事件急剧增多,导致基于区块链的数字资产产生了巨大损失。目前,虽然部分工具可以检测智能合约安全漏洞,但是它们主要针对单个智能合约进行检测,未考虑跨合约之间的... 随着区块链应用的快速发展和智能合约的广泛使用,由智能合约引发的安全事件急剧增多,导致基于区块链的数字资产产生了巨大损失。目前,虽然部分工具可以检测智能合约安全漏洞,但是它们主要针对单个智能合约进行检测,未考虑跨合约之间的交互依赖关系,因此会产生较多的误报。针对上述智能合约漏洞检测工具在跨合约场景下误报率较高和性能消耗过大的问题,文章提出一种基于函数依赖的跨合约模糊测试方案FIFuzz。该方案提出ContractRank算法进行合约间依赖关系建模,采用函数重要度来表征函数在合约间交互过程中的重要程度,并在后续模糊测试模块中加以利用。模糊测试通过基于函数重要度的交易序列生成策略和基于合约地址映射关系的地址类型数据生成策略来提高检测效率,缩减跨合约漏洞检测的搜索空间。另外,通过合约调用模拟来降低漏洞检测的假阳性率。与相关工具的对比实验表明,FIFuzz的漏洞检测时间相对其他工具缩短了80%,检测到的漏洞数量是其他工具的两倍,检测跨合约漏洞的准确率也明显高于其他工具。实验结果表明,FIFuzz能够有效提升跨合约漏洞的检测准确率,降低误报率,并减小时间开销。 展开更多
关键词 智能合约 模糊测试 跨合约漏洞
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Architecture and Methodology of Unit Testing Embedding Pair-Wise Mode for Small Team
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作者 Mengqing TanLi Ying Zhang Yulin Wang 《Journal of Software Engineering and Applications》 2022年第11期385-405,共21页
In this paper, the new organization for unit testing embedding pair-wise mode is proposed with the core thought focused on the cooperation of programmer and tester by “cross-testing”. The typical content of unit tes... In this paper, the new organization for unit testing embedding pair-wise mode is proposed with the core thought focused on the cooperation of programmer and tester by “cross-testing”. The typical content of unit testing for the new organizing mode should have three aspects, including self-checking, cross-testing and independent-testing. For cross-testing, executing “pair-wise” mode, mainly tackles data testing, function testing and state testing, which function testing must be done by details and state testing must be considered for completeness. With the specializing of independent-testing, it should be taken as more rigid testing without arbitrariness. Consequently, strategy and measure are addressed for data testing focusing on boundary testing and function/state testing. And organizing method of procedure and key points of tackling unit testing are investigated for the new organizing mode. In order to assess the validity of our study and approach, a series of actual examples are demonstrated for GUI software. The result indicates that the execution of unit testing for the new organizing mode is effective and applicable. 展开更多
关键词 Unit testing Organizing Architecture Pair-Wise Mode cross-testing Data testing Function/State testing Boundary testing Small Team
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RCS SCALE-MODEL-TESTING METHOD BY VARIANCE IN THE SIZE FOR SIMPLY SHAPED SCATTERERS
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作者 刘宏伟 时振栋 唐璞 《Journal of Electronics(China)》 1995年第2期177-180,共4页
t According to a general representation of physical scale factor of RCS for variance in the size of simply shaped scatterers, a novel RCS model-testing method is described. The computed results of the prototype scatte... t According to a general representation of physical scale factor of RCS for variance in the size of simply shaped scatterers, a novel RCS model-testing method is described. The computed results of the prototype scatterers by this method from the model-testing agree well with their measured values both for two kinds of simply shaped scatterers, cylinders and ladder-shaped plates. 展开更多
关键词 Radar-cross-section(RCS) Model-testing Scale factor Physical-optic approximation
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复杂受荷下盾构隧道原型结构试验平台的研发与实证 被引量:1
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作者 柳献 刘震 +1 位作者 叶宇航 姚鸿梁 《岩土工程学报》 EI CAS CSCD 北大核心 2024年第5期927-937,共11页
盾构隧道结构在全寿命周期中往往将面临诸多复杂荷载状态,如注浆、偏载、偏转等非对称偏不利工况。为验证结构在这些复杂荷载状态下的适用性,探究结构力学性能,开展足尺原型结构试验研究往往是最为直接而有效的手段。既有原型试验主要... 盾构隧道结构在全寿命周期中往往将面临诸多复杂荷载状态,如注浆、偏载、偏转等非对称偏不利工况。为验证结构在这些复杂荷载状态下的适用性,探究结构力学性能,开展足尺原型结构试验研究往往是最为直接而有效的手段。既有原型试验主要关注隧道结构在简单对称荷载条件下的力学性能,鲜有关注复杂非对称荷载状态。为拓展原型试验的适用范围,提出了适用于不同断面盾构隧道结构的原型试验平台和用于模拟复杂荷载状态的试验荷载设计方法。该方法适用于任意加载点布置和液压站分组的试验系统,可对注浆、偏载、偏转等复杂荷载状态下结构响应进行精确模拟。通过类矩形盾构隧道、双圆隧道和圆形隧道的偏载原型结构试验研究,验证了试验平台和试验荷载设计方法的适用性。进一步针对试验关键参数的分析表明,控制目标权重系数的调整能有效满足不同的试验模拟要求;基于试验荷载设计方法优化的迭代算法能有效考虑计算模型或边界支承条件的非线性;环箍钢绞线和千斤顶的组合加载模式能将拟合误差水平降低至千斤顶加载模式的1/5,但需要删去部分加载点使试验荷载合理且适用;对于越复杂的结构和荷载,精确模拟结构状态需要的试验系统独立荷载组数越高,对试验平台的要求也越高。 展开更多
关键词 复杂受荷状态 原型试验 试验平台 试验荷载设计 断面形式
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一种在线快速图像抖动消除方法及其在疲劳试验中的应用
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作者 张文东 陈莉 +1 位作者 陈先民 苏少普 《应用力学学报》 CAS CSCD 北大核心 2024年第6期1274-1281,共8页
提出一种基于先验信息的直方图匹配算法,以实现疲劳试验中试件观测图像抖动的在线快速消除。首先,根据灰度阈值对基准帧图像和目标帧图像计数统计形成直方图;其次,采用傅里叶变换将直方图变换为频域信息,并根据先验信息确定偏移阈值,进... 提出一种基于先验信息的直方图匹配算法,以实现疲劳试验中试件观测图像抖动的在线快速消除。首先,根据灰度阈值对基准帧图像和目标帧图像计数统计形成直方图;其次,采用傅里叶变换将直方图变换为频域信息,并根据先验信息确定偏移阈值,进行互相关分析从而获得互相关数组;最后,选取互相关数组中的最大值,并根据最大值位置确定目标帧图像的抖动量,进行图像抖动的消除。基于先验信息的互相关频域分析极大地降低了计算量,从而使得本研究方法可以实现高分辨率图像中抖动的在线快速消除。试验结果表明,对于分辨率为4096×3000的图像,在保持抖动消除效果不变的情况下,本研究算法与传统方法相比,计算效率提高了3倍,能满足疲劳试验中试件观测的试验应用需求。 展开更多
关键词 疲劳试验 图像消抖 直方图匹配 互相关分析 傅里叶变换
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Research on Well Testing Interpretation of Low Permeability Deformed Dual Medium Reservoir
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作者 Meinan Wang Yue Xie +2 位作者 Rui Zhang Guohao Zhang Jianguo Liu 《Open Journal of Applied Sciences》 2023年第11期2141-2148,共8页
Considering the influence of quadratic gradient term and medium deformation on the seepage equation, a well testing interpretation model for low permeability and deformation dual medium reservoirs was derived and esta... Considering the influence of quadratic gradient term and medium deformation on the seepage equation, a well testing interpretation model for low permeability and deformation dual medium reservoirs was derived and established. The difference method was used to solve the problem, and pressure and pressure derivative double logarithmic curves were drawn to analyze the seepage law. The research results indicate that the influence of starting pressure gradient and medium deformation on the pressure characteristic curve is mainly manifested in the middle and late stages. The larger the value, the more obvious the upward warping of the pressure and pressure derivative curve;the parameter characterizing the dual medium is the crossflow coefficient. The channeling coefficient determines the time and location of the appearance of the “concave”. The smaller the value, the later the appearance of the “concave”, and the more to the right of the “concave”. 展开更多
关键词 Low Permeability Oil Reservoirs Deformation Medium Dual Media cross Flow Coefficient Well testing Interpretation Model
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应用霍普金森压杆试验分析柠条动态力学特性
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作者 李春东 张家宁 +1 位作者 曹丽英 张晓礼 《东北林业大学学报》 CAS CSCD 北大核心 2024年第5期102-106,共5页
为研究柠条的动态力学特性,采用分离式霍普金森压杆(SHPB)装置对柠条的横纹、顺纹试件进行动态压缩试验。通过改变驱动气压,使撞击杆分别以12、19、26 m·s^(-1)的初速度对入射杆撞击,比较不同应变率时,柠条试件的应力表现、破坏形... 为研究柠条的动态力学特性,采用分离式霍普金森压杆(SHPB)装置对柠条的横纹、顺纹试件进行动态压缩试验。通过改变驱动气压,使撞击杆分别以12、19、26 m·s^(-1)的初速度对入射杆撞击,比较不同应变率时,柠条试件的应力表现、破坏形态。结果表明:在相同的冲击能作用时,柠条顺纹试件的动态屈服应力强于横纹试件;随着应变率的提升,顺纹试件的动态屈服强度变化程度高于横纹试件,且应变率效应亦强于横纹试件。由动态应力-应变特性可知,柠条横纹试件经历弹性变形和弱强化两个阶段,顺纹试件经历弹性变形和压溃两个阶段。对柠条横纹试件动态屈服点后的应力-应变特性曲线,采用修正后的Johnson-Cook(J-C)本构模型进行拟合,获得良好的拟合度。 展开更多
关键词 柠条 霍普金森压杆试验 顺纹 横纹 动态力学特性
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