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Relationship between Authoritative Parenting Style and Preschool Children’s Emotion Regulation:A Moderated Mediation Model
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作者 Yan Jin Wei Chen 《International Journal of Mental Health Promotion》 2024年第3期189-198,共10页
An authoritative parenting style has been shown to promote children’s emotion regulation in European-American family studies.However,little is known about how sleep problems and the child’s sibling status in Chinese... An authoritative parenting style has been shown to promote children’s emotion regulation in European-American family studies.However,little is known about how sleep problems and the child’s sibling status in Chinese families affect this relationship.Based on family system theory,this study attempts to better understand the relationship between authoritative parenting style and emotion regulation.Mothers of preschool children in Chinese kindergartens completed questionnaires about their children’s sleep habits,their authoritative parenting styles,and children’s emotion regulation.A total of 531 children participated in this study.Results showed that authoritative parenting was positively associated with emotional regulation.Sleep problems mediated the effects of authoritative parenting style on emotion regulation.The child’s sibling status moderated the mediating effects of sleep problems in authoritative parenting and emotion regulation relationships.Specifically,the relationship between the authoritative parenting style and sleep problems was significant for only children,while birth order had no significant influence on the authoritative parenting style and sleep problems in two-child families.These findings suggest that a lowauthoritative parenting style predicts low emotion regulation through sleep problems,and this depends on the child’s sibling status,indicating that children without siblings may impair emotion regulation due to increased sleep problems. 展开更多
关键词 sleep problem emotional regulation authoritative parenting child’s sibling status preschool children
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Investigation on variations of apparent stress in the region in and around the rupture volume preceding the occurrence of the 2021 Alaska MW8.2 earthquake 被引量:1
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作者 Xuezhong Chen Yane Li Lijuan Chen 《Earthquake Science》 2022年第3期147-160,共14页
On July 29, 2021, a large earthquake of MW8.2 occurred south of the Alaska Peninsula. To investigate the spatial-temporal changes of crustal stress in the earthquake-stricken area before this event, we selected 159 ea... On July 29, 2021, a large earthquake of MW8.2 occurred south of the Alaska Peninsula. To investigate the spatial-temporal changes of crustal stress in the earthquake-stricken area before this event, we selected 159 earthquakes of 4.7 ≤ MW ≤ 6.9 that occurred in the epicentral region and its surroundings between January 1980 and June 2021 to study the temporal variation and spatial distribution of their apparent stress. In addition, we analyzed the correlation between seismic activities and Earth’s rotation and explored the seismogenic process of this earthquake. The crustal stress rose from January 2008 to December 2016. This period was followed by a sub-instability stage from January 2017 until the occurrence of the MW8.2 earthquake. The average rate of apparent stress change in the first five years of the stress increase period was roughly 2.3 times that in the last four years. The lateral distribution of the apparent stress shows that the areas with apparent stress greater than 1.0 MPa exhibited an expanding trend during the seismogenic process. The maximum apparent stress was located at the earthquake epicenter during the last four years. The distribution of the apparent stress in the E-W vertical cross section revealed that an apparent stress gap formed around the hypocenter during the first five years of the stress increase period, surrounded by areas of relatively high apparent stress. After the Alaska earthquake, most parts of this gap were filled in by aftershocks. The seismic activities during the sub-instability stage exhibited a significant correlation with Earth’s rotation. 展开更多
关键词 MW8.2 earthquake in Alaska apparent stress variation characteristics Earth’s rotation correlation.
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Determinants of disease-specific knowledge among children with inflammatory bowel disease and their parents:A multicentre study
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作者 Kinga Kowalska-Duplaga Anita Gawlik-Scislo +4 位作者 Elzbieta Krzesiek Elzbieta Jarocka-Cyrta IzabellaŁazowska-Przeorek Mariusz Duplaga Aleksandra Banaszkiewicz 《World Journal of Gastroenterology》 SCIE CAS 2021年第27期4468-4480,共13页
BACKGROUND Disease knowledge is associated with increased treatment compliance and improvement of symptoms in inflammatory bowel disease(IBD).IBD-knowledge inventory device(IBD-KID)was developed and validated specific... BACKGROUND Disease knowledge is associated with increased treatment compliance and improvement of symptoms in inflammatory bowel disease(IBD).IBD-knowledge inventory device(IBD-KID)was developed and validated specifically as a tool to measure disease-related knowledge in children with IBD and their parents.AIM To prospectively assess the determinants of disease-related knowledge regarding paediatric IBD patients and their parents,using the IBD-KID.METHODS A questionnaire-based survey was carried out in paediatric patients and their parents.The determinants of patients’and parents’IBD-KID scores were assessed according to hierarchical linear regression models.RESULTS The study group consisted of 269 IBD patients and 298 parents.The patients’mean(standard deviation,SD)IBD-KID score was 10.87(±3.97),while the parents’was 11.95(±3.97).Both groups exhibited poor knowledge of the side effects of steroid therapy,the role of surgical treatment in IBD,dietary restrictions and the risks associated with the use of herbal medicines.The patients’IBD-KID scores were statistically associated with patient sex[B coefficient(standard error,SE)=1.03(0.44),P=0.021]and patient age[B(SE)=0.03(0.01),P<0.001].The parents’IBD-KID scores were significantly related to patient age[B(SE)=0.02(0.01),P=0.003],and treatment with immunosuppressive agent[B(SE)=1.85(0.48),P<0.001].The final models explained 26.9%of the variance of patients’IBD-KID scores and 18.5%of the variance of parents’scores.CONCLUSION The variables originating from parents’knowledge were significantly associated with patients’IBD-KID scores.The study results indicate the need to implement better education programmes for patients and parents. 展开更多
关键词 Crohn’s disease Inflammatory bowel disease-knowledge inventory device KNOWLEDGE parents Ulcerative colitis
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Parents' Experiences of When an Adult Child Is Seriously III--"lt Does Not Matter That It Is a Grown-Up Person, They Are Still Your Child"
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作者 Inger Benkel Ulla Molander 《Journal of Health Science》 2015年第4期165-173,共9页
Purpose and Topic: A longer life expectancy is expected to rise continuously in all populations on all continents. Older parents are at risk of having to accompany their adult children through a severe illness, somet... Purpose and Topic: A longer life expectancy is expected to rise continuously in all populations on all continents. Older parents are at risk of having to accompany their adult children through a severe illness, sometimes even to their death. The present study investigates the experiences of being a parent to an adult child with a severe illness and what support was helpful during the child's period of illness. Method: A qualitative approach with in-depth interviews which were analyzed using content analysis. Results: The results showed that a common perception was that it is very special to have a child with a severe illness. The underlying elements of existential experience and the relationship both influenced the parents' conceptions of life and permeated the whole situation. There were four areas that the parents found important and influenced how they could manage the situation: having information, participation, strategies to cope with the situation, and support. Conclusions: Accompanying an adult child through a severe and potentially fatal disease in the context of a growing elderly population will become an increasingly frequent problem. So far there is limited research in this area and more research should be a high priority in the future. 展开更多
关键词 parent grieving adult children's illness grieving adult child.
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Fifty-Six Big Data V’s Characteristics and Proposed Strategies to Overcome Security and Privacy Challenges (BD2)
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作者 Abou_el_ela Abdou Hussein 《Journal of Information Security》 2020年第4期304-328,共25页
The amount of data that is traveling across the internet today, including very large and complex set of raw facts that are not only large, but also, complex, noisy, heterogeneous, and longitudinal data as well. Compan... The amount of data that is traveling across the internet today, including very large and complex set of raw facts that are not only large, but also, complex, noisy, heterogeneous, and longitudinal data as well. Companies, institutions, healthcare system, mobile application capturing devices and sensors, traffic management, banking, retail, education etc., use piles of data which are further used for creating reports in order to ensure continuity regarding the services that they have to offer. Recently, Big data is one of the most important topics in IT industry. Managing Big data needs new techniques because traditional security and privacy mechanisms are inadequate and unable to manage complex distributed computing for different types of data. New types of data have different and new challenges also. A lot of researches treat with big data challenges starting from Doug Laney’s landmark paper</span><span style="font-family:Verdana;">,</span><span style="font-family:Verdana;"> during the previous two decades;the big challenge is how to operate a huge volume of data that has to be securely delivered through the internet and reach its destination intact. The present paper highlights important concepts of Fifty</span><span style="font-family:Verdana;">-</span><span style="font-family:Verdana;">six Big Data V’s characteristics. This paper also highlights the security and privacy Challenges that Big Data faces and solving this problem by proposed technological solutions that help us avoiding these challenging problems. 展开更多
关键词 Big Data Big Data V’s characteristics security PRIVACY CHALLENGEs Technological solutions
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Children's Social Emotional and Cognitive Development Association with Parent and Sibling
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作者 王肖莲 《海外英语》 2016年第6期73-75,共3页
The purpose of this article is to demonstrate the impact on children's development from parents and siblings differed in many aspects through literature review. From the literature review, it shows that parents an... The purpose of this article is to demonstrate the impact on children's development from parents and siblings differed in many aspects through literature review. From the literature review, it shows that parents and siblings contribute differently to children's emotional, social and cognitive development to some extent. Besides,it seems that having a sibling is more likely to benefit the younger siblings, not the older one. 展开更多
关键词 parent and sibling’s INFLUENCE emotinal COGNITIVE development
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Impact of the Changes in Women’s Characteristics over Time on Antenatal Health Care Utilization in Egypt (2000-2008) 被引量:1
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作者 Hassan H. M. Zaky Dina M. Armanious Mohamed Ali Hussein 《Open Journal of Obstetrics and Gynecology》 2015年第10期542-552,共11页
Objectives: This study empirically assesses the impact of the changes in women’s characteristics, empowerment, availability and quality of health services on woman’s decision to use antenatal care (ANC) and the freq... Objectives: This study empirically assesses the impact of the changes in women’s characteristics, empowerment, availability and quality of health services on woman’s decision to use antenatal care (ANC) and the frequency of that use during the period 2000-2008. Study Design: The study is a cross-sectional analytical study using 2000 and 2008 Egypt Demographic and Health Surveys. Methods: The assessment of the studied impact is conducted using the Zero-inflated Negative Binomial Regression. In addition, Factor Analysis technique is used to construct some of the explanatory variables such as women’s empowerment, the availability and quality of health services indicators. Results: Utilization of antenatal health care services is greatly improved from 2000 to 2008. Availability of health services is one of the main determinants that affect the number of antenatal care visits in 2008. Wealth index and quality of health services play an important role in raising the level of antenatal care utilization in 2000 and 2008. However, the impact of the terminated pregnancy on receiving ANC increased over time. Conclusions: Further research of the determinants of antenatal health care utilization is needed, using more updated measures of women’s empowerment, availability and quality of health services. In order to improve the provision of antenatal health care services, it is important to understand barriers to antenatal health care utilization. Therefore, it is advisable to collect information from women about the reasons for not receiving antenatal care. 展开更多
关键词 Women’s characteristics ANTENATAL Health Care Women’s EMPOWERMENT ZERO-INFLATED Negative BINOMIAL Regression EGYPT
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Analysis of the Pump-turbine S Characteristics Using the Detached Eddy Simulation Method 被引量:10
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作者 SUN Hui XIAO Ruofu +2 位作者 WANG Fujun XIAO Yexiang LIU Weichao 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2015年第1期115-122,共8页
Current research on pump-turbine units is focused on the unstable operation at off-design conditions, with the characteristic curves in generating mode being S-shaped. Unlike in the traditional water turbines, pump-tu... Current research on pump-turbine units is focused on the unstable operation at off-design conditions, with the characteristic curves in generating mode being S-shaped. Unlike in the traditional water turbines, pump-turbine operation along the S-shaped curve can lead to difficulties during load rejection with unusual increases in the water pressure, which leads to machine vibrations. This paper describes both model tests and numerical simulations. A reduced scale model of a low specific speed pump-turbine was used for the performance tests, with comparisons to computational fluid dynamics(CFD) results. Predictions using the detached eddy simulation(DES) turbulence model, which is a combined Reynolds averaged Naviers-Stokes(RANS) and large eddy simulation(LES) model, are compared with the two-equation turbulence mode results. The external characteristics as well as the internal flow are for various guide vane openings to understand the unsteady flow along the so called S characteristics of a pump-turbine. Comparison of the experimental data with the CFD results for various conditions and times shows that DES model gives better agreement with experimental data than the two-equation turbulence model. For low flow conditions, the centrifugal forces and the large incident angle create large vortices between the guide vanes and the runner inlet in the runner passage, which is the main factor leading to the S-shaped characteristics. The turbulence model used here gives more accurate simulations of the internal flow characteristics of the pump-turbine and a more detailed force analysis which shows the mechanisms controlling of the S characteristics. 展开更多
关键词 PUMP-TURBINE s-shaped characteristics detached eddy simulation(DEs numerical analysis
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Intersection capacity based on driver's visual characteristics 被引量:5
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作者 陆建 陈伟伟 范红静 《Journal of Southeast University(English Edition)》 EI CAS 2009年第1期117-122,共6页
In order to reflect the influence of the drivers' characteristic differences on intersection capacity under a mixed traffic flow, a driver correction coefficient for the intersection capacity calculation according to... In order to reflect the influence of the drivers' characteristic differences on intersection capacity under a mixed traffic flow, a driver correction coefficient for the intersection capacity calculation according to the driver's visual characteristics is proposed. First, the parameters of the driver's visual characteristics at some real roads, including gaze fixation distribution, mean fixation duration, visual angle distribution and some other parameters at intersections, are collected. Then, the relationship between the traffic flow rate at intersections and the parameters of driver eye movements are established. The analytical results indicate that when the traffic flow is unsaturated, the parameters of driver eye movements change relatively little; however, when the traffic flow is saturated, the parameters of driver eye movements change drastically. Finally, the saturation-flow-rate model is modified according to the parameters of driver eye movements; thus, a capacity model of intersections considering the driver's visual characteristics is obtained. 展开更多
关键词 INTERsECTION driver's visual characteristics saturation-flow-rate capacity compensation factor
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Parents' Perception and their Decision on their Children's Vaccination Against Seasonal Influenza in Guangzhou 被引量:5
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作者 Lei He Qiu-Yan Liao +2 位作者 You-Qi Huang Shuo Feng Xiao-Ming Zhuang 《Chinese Medical Journal》 SCIE CAS CSCD 2015年第3期327-341,共15页
Background: Seasonal influenza epidemic occurs every year in Guangzhou, which can affect all age groups. Young children are the most susceptible targets. Parents can decide whether to vaccinate their children or not ... Background: Seasonal influenza epidemic occurs every year in Guangzhou, which can affect all age groups. Young children are the most susceptible targets. Parents can decide whether to vaccinate their children or not based on their own consideration in China. The aim of this study was to identify factors that are important for parental decisions on vaccinating their children against seasonal influenza based on a modified health belief model (HBM). Methods: A cross-sectional study was conducted in Guangzhou, China. A total of 335 parents who had at least on child aged between 6 months and 3 years were recruited from women and children's hospital in Guangzhou, China. Each eligible subject was invited for a face-to-face interview based on a standardized questionnaire. Results: Uptake of seasonal influenza within the preceding 12 months among the target children who aged between 6 months and 36 months was 47.7%. Around 62.4% parents indicated as being "likely/very likely" to take their children for seasonal influenza vaccination in the next 12 months. The hierarchical logistic regression model showed that children's age (odds ratio [OR] =2.59, 95% confidence interval [C/I: 1.44-4.68), social norm (OR = 2.08, 95% CI: 1.06-4.06) and perceived control (OR - 2.96, 95% CI: 1.60-5.50) were significantly and positively associated with children's vaccination uptake within the preceding 12 months; children with a history of taking seasonal influenza vaccine (OR = 2.50, 95% CI: 1.31-4.76), perceived children's health status (OR = 3.36, 95% C1: 1.68-6.74), worry/anxious about their children influenza infection (OR = 2.31, 95% CI: 1.19-4.48) and perceived control (OR = 3.21, 95% CI: 1.65-6.22) were positively association with parental intention to vaccinate their children in the future 12 months. However, anticipated more regret about taking children for the vaccination was associated with less likely to vaccinate children within the preceding 12 months (OR = 0.21, 95% CI: 0.08-0.52). Conclusions: The modified HBM provided a good theoretical basic for understanding factors associated with parents' decisions on their children's vaccination against seasonal influenza. 展开更多
关键词 Children's Vaccination Health Belief Model parents Perception and their Decision seasonal Influenza
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Characteristics of Child Labour and Their Health Problems: Findings from Rural Community of India
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作者 Sourav Mondal Koustuv Dalal +1 位作者 Dilip Kumar Sahoo Animesh Biswas 《Health》 CAS 2016年第10期931-936,共7页
Background: Child labour is a big problem. Studies have indicated several problems of child labour. However, few studies have indicated the characteristics of child labour rural India. Objectives: This study has explo... Background: Child labour is a big problem. Studies have indicated several problems of child labour. However, few studies have indicated the characteristics of child labour rural India. Objectives: This study has explored characteristics of child labour and their families in the rural community of eastern India and also identified their health problems. Methods: A cross-sectional study was designed to explore their characteristics in purposively selected areas in rural Howrah, India. Frequency table and bar-diagrams were used. Results: The study identified 72% boys and 28% girls as child labour. Majority of the children (67.9%) were labour because they wanted to help their parents. In 8.9% cases, they were forced to work by their parents. In 5.4% cases, they were orphans. Majority of the children were not satisfied (78.6%) with their job place and job status. Conclusions: Child labourers are not satisfied with their job. Their money is used in family. Parents are illiterate. Lack of effective education system and availability of functional schools are both causes and consequences of child labour. Due to illiteracy, working conditions for these children get worse as they are not even aware of the occupational benefits. 展开更多
关键词 Child Labour characteristics parents ILLITERACY Rural INDIA
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Is the higher rate of parental child homicide in stepfamilies an effect of non-genetic relatedness?
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作者 Hans TEMRIN Johanna NORDLUND +1 位作者 Mikael RYING Birgitta S. TULLBERG 《Current Zoology》 SCIE CAS CSCD 北大核心 2011年第3期253-259,共7页
In an evolutionary perspective individuals are expected to vary the degree of parental love and care in relation to the fitness value that a child represents. Hence, stepparents are expected to show less solicitude th... In an evolutionary perspective individuals are expected to vary the degree of parental love and care in relation to the fitness value that a child represents. Hence, stepparents are expected to show less solicitude than genetically related parents, and this lack of genetic relatedness has been used to explain the higher frequencies of child abuse and homicide found in stepfamilies. However, other factors than non-genetic relatedness may cause this over-representation in stepfamilies. Here we use a 45-year data set of parental chiltl homicides in Sweden to test two hypotheses related to the higher incidence in stepfamilies: 1) adults in different types of family differ in their general disposition to use violence, and 2) parents are more likely to kill stepchildren than genetically related children. Of the 152 perpetrators in biparental families there was an overrepresentation of perpetrators in step- families (n=27) compared with the general population. We found support for the first hypothesis in that both general and violent crime rates were higher in stepfamilies, both in the general population and among perpetrators of child homicide. However, we found no support for the second hypothesis because of the 27 perpetrators in stepfamilies the perpetrator killed a genetically related child in 13 cases, a stepchild in 13 cases and both types of children in one case. Moreover, out of the 12 families where the perpetrator lived with both stepchildren and genetic children, there was no bias towards killing stepchildren. Thus, we found no evidence for an effect of non-genetic relatedness per se [Current Zoology 57 (3): 253-259, 2011]. 展开更多
关键词 Cinderella effect Alternative explanations characteristics of parents Previous criminality Violence
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甘肃积石山 M_(s)6.2级地震的震害特征与启示 被引量:6
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作者 王丽丽 王兰民 +5 位作者 卢育霞 许世阳 夏晓雨 盖海龙 池佩红 郭梅 《世界地震工程》 北大核心 2024年第1期58-71,共14页
2023年12月18日,甘肃省临夏回族自治州积石山保安族东乡族撒拉族自治县(35.70°N,102.79°E)发生了6.2级地震,震中烈度为VIII度。地震发生后,通过实地烈度评估与科学考察,对震区VI~VIII度区不同建(构)筑物与生命线工程的震害特... 2023年12月18日,甘肃省临夏回族自治州积石山保安族东乡族撒拉族自治县(35.70°N,102.79°E)发生了6.2级地震,震中烈度为VIII度。地震发生后,通过实地烈度评估与科学考察,对震区VI~VIII度区不同建(构)筑物与生命线工程的震害特点进行了统计分析;从抗震设计与施工管理、场地放大效应与地震次生灾害对建筑结构抗震性能的影响等角度,提出了此次地震的震害启示。结果表明:1)严重破坏和毁坏的建筑结构主要集中在老旧的土木结构、砖木结构和无设防或设防不规范的砖混结构。2)造成建筑结构破坏的主要原因是少量自建房抗震设计和施工的不规范、场地放大效应和地震次生灾害。3)优化和改良生土砌筑材料,改进纵横墙间的拉结措施,强化结构整体性是提高土木结构抗震的有效方法;普及“上下圈梁与构造柱”等基本抗震设防措施,规范水泥砂浆强度,提升农村工匠的施工水平,可有效提高砌体结构的整体性,避免房屋出现整体性垮塌;室内洗手间的墙体应该与房顶、纵横墙间建立有效联接,提高结构的抗震性能。4)孤突斜坡、河流高阶地与岸边为抗震不利地带。当建造用地极为匮乏,不得不选址在这些场地之上时,应该综合考虑场地的地形地貌特征、岩土体物理力学特性、水文地质条件、抗震设防目标、建筑结构类型等影响因素,做好地震灾害风险评估,根据评估结果进行科学设防。灾后重建过程中,应由政府统一规划选址、统一设计,规范施工。 展开更多
关键词 积石山6.2级地震 震害调查 场地放大效应 黄土液化流滑 震害特征
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改变导叶翼型对水泵水轮机“S”特性的影响 被引量:1
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作者 李琪飞 谢耕达 +1 位作者 韩天丁 李正贵 《排灌机械工程学报》 CSCD 北大核心 2024年第1期1-7,共7页
针对水泵水轮机“S”特性区域的不稳定性问题,提出使用改型活动导叶翼型进行性能提升.以某水泵水轮机模型为研究对象,采用SST k-ω湍流模型对水泵水轮机全流道进行三维数值计算,通过对活动导叶翼型的改型设计,得出流量-转速模拟曲线,分... 针对水泵水轮机“S”特性区域的不稳定性问题,提出使用改型活动导叶翼型进行性能提升.以某水泵水轮机模型为研究对象,采用SST k-ω湍流模型对水泵水轮机全流道进行三维数值计算,通过对活动导叶翼型的改型设计,得出流量-转速模拟曲线,分析水泵水轮机组“S”特性改善情况.将计算与试验结果进行对比,并对改型活动导叶翼型前后机组的无叶区进行压力脉动分析.结果表明:在保证整体效率依然保持在92%附近的前提下,新的活动导叶翼型对机组的“S”特性依旧具有改善效果;无叶区压力脉动主要是受到活动导叶叶栅区域的分流在此重新聚集影响,并且与转轮叶片的动静相互扰动引起的;改型后的活动导叶降低了无叶区的压力脉动幅值,提升了水泵水轮机运行中的并网稳定性. 展开更多
关键词 水泵水轮机 s”特性曲线 活动导叶 翼型设计 数值计算
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基于数值模拟的高速公路S型曲线积水规律分析
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作者 吴文亮 曾威凯 +1 位作者 李智 王晓飞 《华南理工大学学报(自然科学版)》 EI CAS CSCD 北大核心 2024年第8期56-64,共9页
S型曲线由于特殊的线型几何特征形成了易积水的路面区域,对于积水规律的掌握有利于在设计和建造阶段提前预防和处理积水路段的危害。该文基于计算流体力学软件Fluent,结合计算流体力学分析中基于欧拉-拉格朗日方法的欧拉液膜模型EWF(Eul... S型曲线由于特殊的线型几何特征形成了易积水的路面区域,对于积水规律的掌握有利于在设计和建造阶段提前预防和处理积水路段的危害。该文基于计算流体力学软件Fluent,结合计算流体力学分析中基于欧拉-拉格朗日方法的欧拉液膜模型EWF(Eulerian Wall Film),针对精细化处理的典型S型曲线双向多车道道路模型进行模拟计算。模拟包含了几何特征与降雨量等不同变量因素,得出了积水的水膜厚度以及流速分布规律。模拟结果表明:在降雨阶段,S型曲线横坡坡度0%~1%路段为积水路段,横坡坡度1%~2%路段为易积水路段,横坡坡度大于2%的路段积水情况受到降雨强度影响;在排水阶段,S型曲线横坡坡度0%~1%路段为排水困难路段,横坡坡度1%~2%路段为排水不畅路段,横坡坡度大于2%的路段排水顺畅,在排水时间结束时,路面在不同的几何条件和降雨条件下均能将积水排除至水膜厚度小于2 cm,横坡的大小与渐变影响了积水的横向分布与纵向分布,横向呈现中间高两边低、横断面上标高大的位置水膜厚度小和标高小的位置水膜厚度大的水膜厚度分布规律,总体呈现S型的分布规律;水膜流速在积水阶段呈现纵向上中间低两边高、水膜厚度大则水膜流速大的水膜厚度分布规律,在排水阶段则为纵向上中间高两边低的水膜流速分布规律。道路宽度影响了降雨落到路面的积水总量,进而对积水水膜厚度产生了影响;超高缓和率则主要使得积水路段、易积水路段增长,从而影响了积水分布的范围。 展开更多
关键词 计算流体力学 s型曲线 路面积水 积水规律
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K-S变换及其电网超谐波时频分析应用
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作者 滕召胜 梁成斌 +2 位作者 唐求 张雷鹏 成达 《湖南大学学报(自然科学版)》 EI CAS CSCD 北大核心 2024年第6期128-136,共9页
依据FFT→优化窗→IFFT思路,突破线性时频变换的窗函数积分性能桎梏,实现高性能优化窗函数的线性时频变换应用,建立新型时频变换算法——K-S变换.对信号x(t)的FFT频谱向量进行频移处理后,与该频移点下Kaiser优化窗的频谱向量进行Hadamar... 依据FFT→优化窗→IFFT思路,突破线性时频变换的窗函数积分性能桎梏,实现高性能优化窗函数的线性时频变换应用,建立新型时频变换算法——K-S变换.对信号x(t)的FFT频谱向量进行频移处理后,与该频移点下Kaiser优化窗的频谱向量进行Hadamard乘积,再将乘积结果进行FFT逆变换(IFFT),构造出K-S变换复时频矩阵,由此获得x(t)的时间-频率-幅值、时间-频率-相位三维信息;给出逆变换的数学推导与局部性质、线性性质和变分辨率特性;0~150 kHz电网的稳态与时变超谐波信号仿真实验表明,K-S变换的时域、频域分辨能力均优于流行的短时傅里叶变换、S变换,具有优良的变分辨率性能;0~40 kHz超谐波信号的实测证明,基于K-S变换的超谐波电压幅值测量绝对误差均小于0.032 3 V. 展开更多
关键词 K-s变换 时频分析 Kaiser优化窗 变分辨率特性 电网超谐波
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Sportswomen's Parents Speak About Their Daughters
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作者 HE WEN ZHAO NING 《Women of China》 1994年第4期18-19,共2页
Leading track-and-field athlete Wang Junxia is from Dalian, in Northeast China’s Liaoning Province. There
关键词 sportswomen’s parents speak About Their Daughters
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基于哨兵函数和S变换的风力机叶片材料损伤特性研究
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作者 廖力达 舒王咏 +3 位作者 张芝铭 刘亮 冯飞 陈为强 《太阳能学报》 EI CAS CSCD 北大核心 2024年第7期656-663,共8页
利用声发射检测技术研究玻璃纤维增强环氧树脂复合材料的损伤特性,在此过程中,采用哨兵函数来表征该材料的损伤程度,并通过S变换和模糊C均值(FCM)聚类来分析声发射信号,从而获得材料的损伤特征。三点弯曲实验结束后对试件断口进行扫描... 利用声发射检测技术研究玻璃纤维增强环氧树脂复合材料的损伤特性,在此过程中,采用哨兵函数来表征该材料的损伤程度,并通过S变换和模糊C均值(FCM)聚类来分析声发射信号,从而获得材料的损伤特征。三点弯曲实验结束后对试件断口进行扫描电子显微镜(SEM)拍照来验证,可得:通过对SEM照片的分析得到基体开裂、纤维脱粘、分层破坏、纤维断裂4种损伤模式;对整个声发射事件进行哨兵函数分析,观察到试件在弯曲过程中哨兵函数曲线呈明显下降趋势;对依据哨兵函数划分的不同阶段的信号进行VMD降噪处理,然后采用S变换进行时频分析得到不同损伤的特征频率,最后采用FCM聚类进行验证。结果表明:哨兵函数值的突变可作为材料断裂的预警信号,材料损伤类型的识别可依据S变换的频率分布结果进行确定。 展开更多
关键词 风力机叶片 复合材料 声发射 损伤特性 哨兵函数 s变换
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湿气环境中CO_(2)-H_(2)S在α-Fe(110)密排面上吸附与点蚀机理研究
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作者 李金灵 马文骏 +2 位作者 朱世东 屈撑囤 付安庆 《表面技术》 EI CAS CSCD 北大核心 2024年第20期82-93,共12页
目的从微观尺度探究CO_(2)-H_(2)S(CO_(2)和H_(2)S共存)在湿气管道顶部的吸附特性,进而揭示点蚀机理。方法基于密度泛函理论的第一性原理,利用Materials Studio构建CO_(2)、H_(2)S和CO_(2)-H_(2)S在α-Fe(110)密排面的吸附模型,对CO_(2)... 目的从微观尺度探究CO_(2)-H_(2)S(CO_(2)和H_(2)S共存)在湿气管道顶部的吸附特性,进而揭示点蚀机理。方法基于密度泛函理论的第一性原理,利用Materials Studio构建CO_(2)、H_(2)S和CO_(2)-H_(2)S在α-Fe(110)密排面的吸附模型,对CO_(2)、H_(2)S和CO_(2)-H_(2)S在α-Fe(110)面的吸附能、局域态密度、分波态密度和差分电荷密度进行仿真;利用高温高压釜模拟CO_(2)-H_(2)S-Cl^(-)腐蚀环境,分析L360钢在湿气环境中的腐蚀行为;最后,揭示含Cl^(-)湿气管道顶部CO_(2)-H_(2)S吸附机制与点蚀机理。结果CO_(2)、H_(2)S、CO_(2)-H_(2)S及CO_(2)-H_(2)S-Cl^(-)在最稳定位置时的吸附能分别为-4.065、-3.961、-8.538、-12.775e V,表明相较于CO_(2)与H_(2)S单独吸附,CO_(2)-H_(2)S在α-Fe(110)面的吸附能更负,Cl^(-)会进一步降低CO_(2)-H_(2)S的吸附能;且CO_(2)在与H_(2)S竞争环境电子中占优势;Cl^(-)会使CO_(2)-H_(2)S的局域态密度峰值降低,转移趋势为失去电子,基体和腐蚀介质的电子向着低能级跃迁释放出更多能量,进而加强了Fe与CO_(2)-H_(2)S间的化学键强度;Cl^(-)的2p轨道与Fe的3d轨道在-6.8 eV和-5.7 eV发生重叠,Cl^(-)被吸附到Fe表面并与Fe形成化学键生成氯化物,进而改变腐蚀产物膜的组分与结构,削弱产物膜的致密性和稳定性,减弱腐蚀阻抗力。在含Cl^(-)湿气的CO_(2)-H_(2)S环境中,液相中的Cl^(-)浓度升高,使L360钢的气相平均腐蚀速率逐渐增大,最高达2.935mm/a,点蚀越发严重。结论CO_(2)与H_(2)S在α-Fe(110)面吸附存在一定的协同和竞争作用,协同促进金属的腐蚀,FeCO3会优先沉积成膜,但H_(2)S会抑制FeCO3的生长,腐蚀产物以FeS为主;Cl^(-)会增强CO_(2)-H_(2)S与α-Fe(110)面间的作用力,弱化腐蚀产物膜层的保护性,进一步加速金属腐蚀、尤其是点蚀。 展开更多
关键词 CO_(2)-H_(2)s Cl^(-) 第一性原理 α-Fe(110)密排面 吸附特征 腐蚀机理
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Isolation and algae-lysing characteristics of the algicidal bacterium B5 被引量:31
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作者 MU Rui-min FAN Zheng-qiu +3 位作者 PEI Hai-yan YUAN Xue-liang Liu Si-xiu WANG Xiang-rong 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2007年第11期1336-1340,共5页
Water blooms have become a worldwide environmental problem. Recently, algicidal bacteria have attracted wide attention as possible agents for inhibiting algal water blooms. In this study, one strain of algicidal bacte... Water blooms have become a worldwide environmental problem. Recently, algicidal bacteria have attracted wide attention as possible agents for inhibiting algal water blooms. In this study, one strain of algicidal bacterium B5 was isolated from activated sludge. On the basis of analysis of its physiological characteristics and 16S rDNA gene sequence, it was identified as Bacillusfusiformis. Its algaelysing characteristics on Microcystis aeruginosa, Chlorella and Scenedesmus were tested. The results showed that: (1) the algicidal bacterium B5 is a Gram-negative bacterium. The 16S rDNA nucleotide sequence homology of strain B5 with 2 strains of B. fusiformis reached 99.86%, so B5 was identified as B. fusiformis; (2) the algal-lysing effects of the algicidal bacterium B5 on M. aeruginosa, Chlorella and Scenedesrnus were pronounced. The initial bacterial and algal cell densities strongly influence the removal rates of chlorophyll-a. The greater the initial bacterial cell density, the faster the degradation of chlorophyll-a. The greater the initial algal cell density, the slower the degradation of chlorophyll-a. When the bacterial cell density was 3.6 × 10^7 cells/ml, nearly 90% of chlorophyll-a was removed. When the chlorophyll-a concentration was less than 550 μg/L, about 70% was removed; (3) the strain B5 lysed algae by secreting metabolites and these metabolites could bear heat treatment. 展开更多
关键词 algicidal bacteria water blooms algae-lysing characteristic 16s rDNA Bacillusfusiformis
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