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Risk factors, prevention and screening of colorectal cancer: A rising problem
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作者 Vladislav V Tsukanov Alexander V Vasyutin Julia L Tonkikh 《World Journal of Gastroenterology》 2025年第5期117-123,共7页
Colorectal cancer(CRC)is the third most commonly diagnosed cancer and the second leading cause of cancer death worldwide.The leading risk factors for CRC include male gender,age over 50,family history,obesity,tobacco ... Colorectal cancer(CRC)is the third most commonly diagnosed cancer and the second leading cause of cancer death worldwide.The leading risk factors for CRC include male gender,age over 50,family history,obesity,tobacco smoking,alco-hol consumption,and unhealthy diet.CRC screening methods vary considerably between countries and depend on incidence,economic resources and healthcare structure.Important aspects of screening include adherence,which can vary signi-ficantly across ethnic and socioeconomic groups.Basic concepts of CRC screening include pre-stratification of patients by identifying risk factors and then using fecal immunochemical test or guaiac-based fecal occult blood test and/or colono-scopy or radiologic imaging techniques.Technological capabilities for CRC scree-ning are rapidly evolving and include stool DNA test,liquid biopsy,virtual colo-nography,and the use of artificial intelligence.A CRC prevention strategy should be comprehensive and include active patient education along with targeted imple-mentation of screening. 展开更多
关键词 Colorectal cancer SCREENING PREVENTION Risk factors Colonoscopy Fecal immunochemical test Fecal occult blood test Stool DNA test Diet Lynch syndrome
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A novel detection method for warhead fragment targets in optical images under dynamic strong interference environments
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作者 Guoyi Zhang Hongxiang Zhang +4 位作者 Zhihua Shen Deren Kong Chenhao Ning Fei Shang Xiaohu Zhang 《Defence Technology(防务技术)》 2025年第1期252-270,共19页
A measurement system for the scattering characteristics of warhead fragments based on high-speed imaging systems offers advantages such as simple deployment,flexible maneuverability,and high spatiotemporal resolution,... A measurement system for the scattering characteristics of warhead fragments based on high-speed imaging systems offers advantages such as simple deployment,flexible maneuverability,and high spatiotemporal resolution,enabling the acquisition of full-process data of the fragment scattering process.However,mismatches between camera frame rates and target velocities can lead to long motion blur tails of high-speed fragment targets,resulting in low signal-to-noise ratios and rendering conventional detection algorithms ineffective in dynamic strong interference testing environments.In this study,we propose a detection framework centered on dynamic strong interference disturbance signal separation and suppression.We introduce a mixture Gaussian model constrained under a joint spatialtemporal-transform domain Dirichlet process,combined with total variation regularization to achieve disturbance signal suppression.Experimental results demonstrate that the proposed disturbance suppression method can be integrated with certain conventional motion target detection tasks,enabling adaptation to real-world data to a certain extent.Moreover,we provide a specific implementation of this process,which achieves a detection rate close to 100%with an approximate 0%false alarm rate in multiple sets of real target field test data.This research effectively advances the development of the field of damage parameter testing. 展开更多
关键词 Damage parameter testing Warhead fragment target detection High-speed imaging systems Dynamic strong interference disturbance suppression Variational bayesian inference Motion target detection Faint streak-like target detection
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High-frequency interference waves in low strain dynamic testing of X-section concrete piles 被引量:1
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作者 Qu Liming Fan Yuming +2 位作者 Ding Xuanming Yang Changwei Zhang Yanling 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2021年第4期877-885,共9页
Stress waves propagate along vertical,radial and circumferential directions when a non-uniformly distributed load is applied at one end of a three-dimensional shaft.As a result,the receiving signals are usually mixed ... Stress waves propagate along vertical,radial and circumferential directions when a non-uniformly distributed load is applied at one end of a three-dimensional shaft.As a result,the receiving signals are usually mixed with undesired interference components,often featuring as high-frequency fluctuations.Previous studies have revealed that sectional geometry(shape and size)greatly affects the high-frequency interference.In this study,low strain dynamic testing on full-scale X-section concrete is conducted in order to investigate the influences of high-frequency interference on velocity responses at the pile head.Emphasis is placed on the frequency and peak value of interference waves at various receiving points.Additionally,the effects of the geometrical,and mechanical properties of the pile shaft on high-frequency interference are elaborated on through the three-dimensional finite element method.The results show that the measured wave is obscured by interference waves superposed by two types of high-frequency components.The modulus and cross-sectional area are contributing factors to the frequency and peak value of the interference waves.On the other hand,the position with the least interference is determined,to some extent,by the accurate shape of the X-section. 展开更多
关键词 low strain dynamic testing X-section concrete pile high-frequency interference full-scale model test finite element method
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Spectrum spatial structure characteristic analysis of remote sensing alteration information and interference factors 被引量:1
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作者 杨自安 彭省临 +3 位作者 朱谷昌 石菲菲 邹林 张远飞 《Journal of Central South University》 SCIE EI CAS 2009年第4期647-652,共6页
Based on the statistical characteristics of remote sensing data, the spatial geometric structure characteristics of spectral data and distribution of background, interference and alteration information in characterist... Based on the statistical characteristics of remote sensing data, the spatial geometric structure characteristics of spectral data and distribution of background, interference and alteration information in characteristic space were researched through the analysis of two-dimensional and three-dimensional scatter diagrams. The results indicate that the hyper-space of remote sensing multi-data aggregation belongs to low-dimensional geometric structure, i.e. hyperplane form, and anomalous point groups including alteration information usually dissociate out of hyperplane. Scatter diagrams of remote sensing data band are mainly presented as two distribution forms of single-ellipse and dual-ellipse. Clarifying the relations of three objects of background, disturbance and alteration information in remote sensing images provides an important technical thought and guidance for accurately detecting and extracting remote sensing alteration information. 展开更多
关键词 remote sensing data alteration information BACKGROUND interference factor spectrum spatial structure scatter diagram
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Does Cognitive Interference Induce Measurement Bias in Cognitive Ability Tests?
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作者 Georgia Papantoniou Despina Moraitou +2 位作者 Dimitra Filippidou Effie Katsadima Magda Dinou 《Journal of Behavioral and Brain Science》 2017年第1期21-29,共9页
The aim of this paper was to test for measurement bias, due to cognitive interference on cognitive ability tests, using a structural equation modeling technique. The sample consisted of 231 undergraduate students who ... The aim of this paper was to test for measurement bias, due to cognitive interference on cognitive ability tests, using a structural equation modeling technique. The sample consisted of 231 undergraduate students who were examined with three tests addressed to numerical ability, space visualization and inductive ability, respectively. They were also asked to respond to the Cognitive Interference Questionnaire tapping task-oriented worries while working on the aforementioned tests. In comparing two nested models, one hypothesizing measurement bias due to cognitive interference and one not, results show that the test tapping inductive ability displays measurement bias due to cognitive interference. 展开更多
关键词 COGNITIVE ABILITY tests COGNITIVE interfereNCE Measurement BIAS
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Seismic performance evaluation of water supply pipes installed in a full-scale RC frame structure based on a shaking table test 被引量:1
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作者 Wu Houli Guo Endong +2 位作者 Wang Jingyi Dai Xin Dai Chenxi 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2024年第1期163-178,共16页
As an important part of nonstructural components,the seismic response of indoor water supply pipes deserves much attention.This paper presents shaking table test research on water supply pipes installed in a full-scal... As an important part of nonstructural components,the seismic response of indoor water supply pipes deserves much attention.This paper presents shaking table test research on water supply pipes installed in a full-scale reinforced concrete(RC)frame structure.Different material pipes and different methods for penetrating the reinforced concrete floors are combined to evaluate the difference in seismic performance.Floor response spectra and pipe acceleration amplification factors based on test data are discussed and compared with code provisions.A seismic fragility study of displacement demand is conducted based on numerical simulation.The acceleration response and displacement response of different combinations are compared.The results show that the combination of different pipe materials and different passing-through methods can cause obvious differences in the seismic response of indoor riser pipes. 展开更多
关键词 water supply pipe different materials shaking table test amplification factor seismic fragility
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HIV Testing Decision and Determining Factors in Ghana
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作者 Abdul-Karim Iddrisu Kwaku Opoku-Ameyaw +2 位作者 Francis Kwame Bukari Bashiru Mahama Jerry John Amaasende Akooti 《World Journal of AIDS》 2019年第2期85-104,共20页
Knowledge on individual’s HIV/AIDS status provides a tool to reduce or avoid HIV transmission, spread and mortalities due to HIV-related illness. However, most people still do not know their HIV status because they a... Knowledge on individual’s HIV/AIDS status provides a tool to reduce or avoid HIV transmission, spread and mortalities due to HIV-related illness. However, most people still do not know their HIV status because they are not willing to test for HIV/AIDS due to various reasons. Hence the aim of this paper is to investigate the effects of various risk factors that are likely to influence decision to ever test for HIV/AIDS. The data used in this paper were obtained from the Ghana Demographic and Health Survey (n = 1828 observations and 32 risk factors). We applied the Chi-Square test statistic and the logistic regression model to the data in order to study the effects of these risk factors on one’s decision to ever test for HIV. STATA version 14.1 and R version 3.5.2 were used to carry out the statistical analyses. Generally, the results show that education, especially higher education significantly (OR = 0.53, 95% = 0.230, 0.837) increases the likelihood to ever test for HIV. Also, the younger the age groups the higher the effect and significance in the likelihood to ever test for HIV. We found that HIV-TB co-infection (OR = 0.53, 95% = 0.165, 0.893), use of condom anytime one has sex (OR = 0.31, 95% = 0.054, 0.573), wealth index (OR = 0.46, 95% = 0.137, 0.791), awareness of HIV transmission during child-delivery, number of partners significantly affect HIV testing. Those with many partners are less likely (OR = -0.26, 95% = -0.504, -0.007) to ever test for HIV and those who know that healthy person may have HIV are more likely (OR = 0.41, 95% = 0.137, 0.679) to ever test for HIV. Age is the common significant risk factor of ever tested for HIV across the 10 regions in Ghana. Resources should be allocated for more education on these significant risk factors in order to help in the fight against HIV-Health related issues. 展开更多
关键词 AIDS CHI-SQUARE test Statistic Ghana DEMOGRAPHIC and Health Survey HIV HIV-TB CO-INFECTION LOGISTIC Regression Model Risk factors
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Seroprevalence, Importance of Rapid Testing and Factors Associated with HBsAg Carriage in Pregnancy in Three Referral Maternity Hospitals in Mono (Benin), in 2020
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作者 Aboudou Raïmi Kpossou Djima Patrice Dangbemey +3 位作者 Véronique Mèdessè Tognifodé Barnard Acakpo Jean Sehonou Josiane Angeline Tonato Bagnan 《Open Journal of Gastroenterology》 2023年第9期279-298,共20页
Introduction Difficulties in accessing the screening test for viral hepatitis B in maternity wards could be a factor in underestimating the prevalence of anti-HBV antibodies. The rapid diagnostic orientation test (RDO... Introduction Difficulties in accessing the screening test for viral hepatitis B in maternity wards could be a factor in underestimating the prevalence of anti-HBV antibodies. The rapid diagnostic orientation test (RDOT) could improve seroprevalence and obstetrical prognosis. The aim of this study was to use the rapid diagnostic orientation test (RDOT) to determine the seroprevalence of HBs antigen carriage in pregnant women while highlighting the associated factors. Methods This was a cross-sectional and descriptive study that took place from October to December 2020 (three months) in three (03) reference maternities in western Benin (Mono). Consenting pregnant women received in prenatal consultation had been screened by RDOT. Positive cases were confirmed by ELISA test. The follow-up of these cases made it possible to establish the obstetrical prognosis. Results Of 201 women studied, 11 (5.5%) were positive for RDOT HBV and confirmed by the ELISA test. The factors associated with HBsAg carriage during pregnancy were multiple sexual partnerships (p = 0.01), female circumcision (p = 0.0001), and ignorance of prior HBV serological status (p = 0.0001). No influence of hepatitis B on pregnancy was noted. Conclusion The seroprevalence of hepatitis B in pregnancy was intermediate in the reference maternities of western Benin. The associated factors were multiple sexual partnerships, female circumcision and unawareness of prior HBV status. Free RDOT in maternity wards would improve early detection and management of viral hepatitis B in pregnancy. 展开更多
关键词 Hepatitis B SEROPREVALENCE Associated factors Rapid test BENIN
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Study on the Factors Affecting the Ability of Higher Vocational College Students in Practical English Test
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作者 Siyang LI 《International Journal of Technology Management》 2015年第4期45-46,共2页
Practical English test for higher vocational colleges is examining students learning effect, curriculum arrangement and teaching model rationality, and it is one of the important propositions in the study of English a... Practical English test for higher vocational colleges is examining students learning effect, curriculum arrangement and teaching model rationality, and it is one of the important propositions in the study of English application ability. In practical English test, concreteness, pertinence and practicability are emphasized. It is closely linked with the students' knowledge practice and attracts more attention from school teachers and students to a large extent. In the real interactive teaching and learning, the scores of higher vocational college students in practical English test are affected by many factors. In this paper, the factors affecting the ability of higher vocational college students in practical English test are discussed from teaching model, learning strategies, and the cultivation of the students' English comprehensive ability. 展开更多
关键词 Higher Vocational Colleges Practical English test SCORES factors
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Adaptive detection of range-spread targets in homogeneous and partially homogeneous clutter plus subspace interference
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作者 JIAN Tao HE Jia +3 位作者 WANG Bencai LIU Yu XU Congan XIE Zikeng 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2024年第1期43-54,共12页
Adaptive detection of range-spread targets is considered in the presence of subspace interference plus Gaussian clutter with unknown covariance matrix.The target signal and interference are supposed to lie in two line... Adaptive detection of range-spread targets is considered in the presence of subspace interference plus Gaussian clutter with unknown covariance matrix.The target signal and interference are supposed to lie in two linearly independent subspaces with deterministic but unknown coordinates.Relying on the two-step criteria,two adaptive detectors based on Gradient tests are proposed,in homogeneous and partially homogeneous clutter plus subspace interference,respectively.Both of the proposed detectors exhibit theoretically constant false alarm rate property against unknown clutter covariance matrix as well as the power level.Numerical results show that,the proposed detectors have better performance than their existing counterparts,especially for mismatches in the signal steering vectors. 展开更多
关键词 adaptive detection subspace interference constant false alarm rate Gradient test partially homogeneous environment
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Behavior of transporting pipeline sections without and with hydrogen exposure based on full-scale tests
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作者 Nóra Nagy János Lukács 《China Welding》 CAS 2024年第3期14-24,共11页
Pipeline transport of hydrogen is one of today’s economic and environmental challenges.In order to find safe and reliable application of both existing gas and build new pipelines,it is essential to carry out tests on... Pipeline transport of hydrogen is one of today’s economic and environmental challenges.In order to find safe and reliable application of both existing gas and build new pipelines,it is essential to carry out tests on full-scale pipeline section,including the potentially more dangerous places than the main pipe,the girth welds.For the investigations,pipeline sections of P355NH steel with girth welds were prepared and exposed to pure hydrogen at twice the maximum allowable operating pressure for 41 days.Subsequently,full-scale burst tests were carried out and specimens were cut and prepared from the typical locations of the failed pipeline sections for mechanical,and macro-and microstructural investigations.The results obtained were evaluated and compared with data from previous full-scale tests on pipeline sections without hydrogen exposure.The results showed differences in the behavior of pipeline sections loaded in different ways,with different characteristics of the materials and the welded joints,both in the cases without hydrogen exposure and in the cases exposed to hydrogen. 展开更多
关键词 gas transporting pipeline full-scale pipeline test complex loading condition hydrogen exposure safety factor
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Influence of Factors on Dechromisation of a Cu-Cr alloy in HCl Solution by Orthogonal Test
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作者 Yan Chen Panpan Zhai +2 位作者 Guirong Peng Jianhua Liu Ruijun Zhang 《材料科学与工程(中英文版)》 2010年第10期56-59,共4页
关键词 盐酸溶液 铜铬合金 正交试验 影响因素 溶液浓度 温度上升 HCI 变形
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Analysis and Evaluation of Housing Price Factors Using Mathematical Modeling
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作者 Xing Lyu 《Proceedings of Business and Economic Studies》 2024年第6期17-23,共7页
In recent years,the real estate industry has achieved significant progress,driving the development of related sectors and playing a crucial role in economic growth.However,rapid real estate market expansion has led to... In recent years,the real estate industry has achieved significant progress,driving the development of related sectors and playing a crucial role in economic growth.However,rapid real estate market expansion has led to challenges,particularly concerning housing prices,which have drawn widespread societal attention.This article explores the theories of housing prices,analyzes factors influencing them,and conducts an empirical investigation of the impact of representative factors on ordinary residential prices.Using regression analysis and the entropy weight method,a mathematical model was developed to examine how various factors affect housing prices. 展开更多
关键词 Mathematical modeling Regression analysis Housing price Formation factors Multiple linear regression H ypothesis testing Multiple decision coefficients
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我国宠物饲料安全风险及监管中亟待解决的问题
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作者 孙国荣 陈磊 +1 位作者 金琦琦 周静 《中国饲料》 北大核心 2025年第1期153-156,共4页
近年来,我国宠物饲料行业发展的规模和速度惊人,市场份额不断增大,同时也显露出不少问题。本文侧重于宠物饲料质量安全,从宠物营养要求特点出发,对存在的有害微生物、霉菌毒素、药物及添加剂、有毒有害元素等风险因素进行分析总结,同时... 近年来,我国宠物饲料行业发展的规模和速度惊人,市场份额不断增大,同时也显露出不少问题。本文侧重于宠物饲料质量安全,从宠物营养要求特点出发,对存在的有害微生物、霉菌毒素、药物及添加剂、有毒有害元素等风险因素进行分析总结,同时提出质量安全监管中限量标准、检测方法和监管体系中存在的亟待解决的问题,希望对生产加工、科研开发、监管工作提供参考。 展开更多
关键词 宠物饲料 质量安全 风险因素 限量标准 检测方法 风险监管
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交通循环荷载下橡胶混凝土阻尼耗能特性试验研究
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作者 张玲 陈智超 +1 位作者 彭芯钰 周蓉 《湖南大学学报(自然科学版)》 北大核心 2025年第1期12-23,共12页
橡胶混凝土是以橡胶颗粒为附加集料形成的混凝土,其独特的物理特性和强化效果使其在土木工程中日益推广应用.为了研究橡胶混凝土作为桩承式低路堤体系中桩帽的可行性,制备了不同橡胶颗粒粒径和体积掺量的橡胶混凝土试件,开展了系列静力... 橡胶混凝土是以橡胶颗粒为附加集料形成的混凝土,其独特的物理特性和强化效果使其在土木工程中日益推广应用.为了研究橡胶混凝土作为桩承式低路堤体系中桩帽的可行性,制备了不同橡胶颗粒粒径和体积掺量的橡胶混凝土试件,开展了系列静力抗压试验和循环荷载下滞回特性试验,获得了橡胶混凝土的抗压强度、滞回耗能、阻尼损耗因子、动弹性模量等力学性能指标及其随橡胶颗粒粒径、体积掺量的变化规律.研究发现,随着橡胶颗粒体积掺量的增加,橡胶混凝土试件抗压强度和动弹性模量逐渐呈指数形式降低至某一临界值,该临界值大小与橡胶颗粒粒径大小有关,粒径越小,强度越小,动弹性模量越小;而滞回耗能、损耗因子随橡胶颗粒掺量呈现二次函数变化趋势,先增长后略微下降,且在橡胶颗粒掺量8%~10%左右达到峰值,相较于加载幅值水平,颗粒粒径对能耗的影响较小. 展开更多
关键词 橡胶混凝土 滞回试验 滞回耗能 损耗因子
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基于因子分析的新高考英语效度验证
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作者 陈康 《中国考试》 北大核心 2025年第2期32-40,共9页
2014年以来,新高考英语科依据国家课程标准和高校人才选拔要求深化考试内容改革,设计启用新题型并调整优化了试卷结构。为深入开展新高考英语科效度验证,本研究运用结构方程模型方法分析了新高考英语科实考数据。分析结果显示,高阶因子... 2014年以来,新高考英语科依据国家课程标准和高校人才选拔要求深化考试内容改革,设计启用新题型并调整优化了试卷结构。为深入开展新高考英语科效度验证,本研究运用结构方程模型方法分析了新高考英语科实考数据。分析结果显示,高阶因子模型与数据的拟合效果最佳,可以代表新高考英语科因子结构。其中,一个高阶因子代表整体语言能力,三个一阶因子分别代表听力、阅读和写作能力。该模型的参数估计结果表明,新高考英语试卷结构设计科学合理,新题型考查效果符合预期,并给教学带来启示。 展开更多
关键词 新高考英语 内容改革 结构方程模型 因子分析 效度验证
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Rheological properties of warm mix asphalt binder by DSR test at medium temperature 被引量:6
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作者 张久鹏 刘国强 +2 位作者 杜慧 裴建中 马学军 《Journal of Southeast University(English Edition)》 EI CAS 2015年第3期384-388,共5页
The rheological properties including the complex modulus G* and the phase angle δof matrix and warm mix asphalt (WMA)binders were measured by using the dynamic shear rheometer (DSR ) test at the medium temperatu... The rheological properties including the complex modulus G* and the phase angle δof matrix and warm mix asphalt (WMA)binders were measured by using the dynamic shear rheometer (DSR ) test at the medium temperature ranging from 16 to 40 ℃,and the relationships between the fatigue factor G* sinδand the matrix binder property,WMA additive and test temperature were established.It is found that G* decreases with the increasing temperature while δincreases inversely,and G* of the asphalt binder with high WMA additive dosage is large,and δis small.G*sinδexponentially decreases with the increasing temperature and linearly increases with the increase in additive dosage,and the amplitudes of variation are large at low temperatures and high additive dosages.The effect of WMA additive on the rheological property is more remarkable for the matrix asphalt binder with low G*.Besides,aging has a great effect on the property of matrix asphalt binder,and a slight effect on the interaction between asphalt and additive.The high additive dosage can increase the fatigue cracking potential of the asphalt binder. 展开更多
关键词 warm mix asphalt dynamic shear rheometer (DSR test medium temperature rheological property fatigue factor
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鼠伤寒沙门氏菌群体感应干扰策略研究进展
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作者 肖雪 张红蕊 +3 位作者 张鹏 乔建军 财音青格乐 吴胜波 《食品与发酵工业》 北大核心 2025年第2期382-389,共8页
鼠伤寒沙门氏菌(Salmonella enterica serovar Typhimurium)作为常见的食源性致病菌,由于其耐药性问题而严重危害公共健康。研究表明干扰致病菌的群体感应(quorum sensing,QS)系统是解决其耐药性问题的有效方案之一。QS是细胞间的一种... 鼠伤寒沙门氏菌(Salmonella enterica serovar Typhimurium)作为常见的食源性致病菌,由于其耐药性问题而严重危害公共健康。研究表明干扰致病菌的群体感应(quorum sensing,QS)系统是解决其耐药性问题的有效方案之一。QS是细胞间的一种通讯机制,涉及多种代谢活动,例如生物被膜形成、运动性、毒力因子、黏附和侵袭等过程。为了系统地总结鼠伤寒沙门氏菌的群体感应及其相应的干扰策略,该文首先介绍了S.Typhimurium包含的N-高丝氨酸内酯类、2型自诱导分子、3型自诱导分子、吲哚和扩散信号分子等介导的5种QS系统。然后从信号分子合成、胞外运输及反应、与受体蛋白相互作用3方面总结了对不同QS系统的抑制和促进策略。指出了未来QS干扰策略的开发应更多立足于多靶点和多层次的系统网络,以期为解决沙门氏菌耐药性开辟新的思路。 展开更多
关键词 群体感应干扰 群体感应猝灭 肠道致病菌 抗生素耐药性 生物被膜 毒力因子
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采用端口阻抗测试的车载充电机传导电磁干扰建模方法研究 被引量:1
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作者 李季风 耿宇宇 +2 位作者 贾晋 廖兴林 路青洋 《西安交通大学学报》 EI CAS 北大核心 2025年第1期172-182,共11页
针对电动汽车车载充电机的设计过程中普遍存在的电磁干扰频率范围广、干扰源复杂的问题,提出了一种基于端口阻抗测试的等效电路建模和系统级协同仿真方法。首先,通过对车载充电机系统各部件进行阻抗测试和三维电磁仿真,建立了无源器件... 针对电动汽车车载充电机的设计过程中普遍存在的电磁干扰频率范围广、干扰源复杂的问题,提出了一种基于端口阻抗测试的等效电路建模和系统级协同仿真方法。首先,通过对车载充电机系统各部件进行阻抗测试和三维电磁仿真,建立了无源器件、端口滤波器和高压屏蔽线缆模型,提取了系统印制电路板关键回路的高频寄生参数。其次,建立了有源器件的仿真电路模拟器等效模型,并通过双脉冲实验验证模型的精度;针对功率因数校正电路控制环节的仿真与建模难以同步实现的问题,采用协同建模的方法构建整个系统的等效电路模型。最后,将各部件模型组合在一起,建立了完整的车载充电机系统传导电磁干扰预测模型,并依据相关测试标准进行了系统传导电磁干扰仿真和实验。结果表明:在150 kHz~30 MHz频率范围内,预测结果与实际结果的误差小于9 dB,具有良好的一致性,表明该模型能够精确预测车载充电机系统高压交流端的传导干扰水平,可以有效指导充电机系统的电磁兼容正向设计。 展开更多
关键词 车载充电机 电磁干扰 端口阻抗测试 协同仿真
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流态固化土水泥剂量EDTA滴定法检测影响因素分析
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作者 罗義錬 罗强 +3 位作者 蒋良潍 张良 胡秋辉 覃李兵 《大连理工大学学报》 CAS 北大核心 2025年第1期79-88,共10页
水泥剂量是控制流态固化土强度的关键指标,工程中多采用EDTA滴定法进行检测,但流态固化土制备过程中含水量与水泥水化时间偏差会导致检测数据失真.研究了EDTA二钠标准溶液消耗量随水泥剂量、含水量和水化时间三因素的变化规律;基于回归... 水泥剂量是控制流态固化土强度的关键指标,工程中多采用EDTA滴定法进行检测,但流态固化土制备过程中含水量与水泥水化时间偏差会导致检测数据失真.研究了EDTA二钠标准溶液消耗量随水泥剂量、含水量和水化时间三因素的变化规律;基于回归正交试验,开展了多因素及交互影响的主次关系分析与显著性评价,建立了考虑三因素综合影响的EDTA二钠标准溶液消耗量回归方程.试验表明,EDTA二钠标准溶液消耗量与水泥剂量近似呈线性正相关,随含水量增大或水化时间延长近似线性降低;影响因素主次顺序为水泥剂量、含水量、水化时间,交互作用不显著;因素水平在回归正交试验组范围内,回归方程计算值误差低于2.40%;含水量或水化时间分别偏差2.9%、86min,将造成水泥剂量检测值增减约0.5%.研究成果可为完善流态固化土水泥剂量检测技术提供参考. 展开更多
关键词 流态固化土 水泥剂量 EDTA滴定法 回归正交试验 因素主次关系
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