基于核密度估计多样性采集的背景建模算法     

毛燕芬  施鹏飞 《上海大学学报(英文版)》2005,9(6):506-509

1IntroductionBackground subtraction methods are extensively ex-ploited for moving object detection in videos in manyapplications ,such as traffic monitoring[1],human mo-tion capture[2]and video surveillance[3]. The centralidea behind such methods is to segment foreground ini mage sequences taken from a fixed camera by com-paring each newframe to a model of the scene back-ground . Therefore , correctly and efficiently modelingand updating the background model is one of the mostchallenging aspec…  相似文献   

掺杂剂与基质材料能量匹配的红色有机发光二极管     

朱文清  蒋雪茵  张志林  许少鸿 《上海大学学报(英文版)》2003,7(2):191-195

1　Introduction　Organiclight emittingdiodes(OLEDs)haveattract edconsiderableattentionduetoitsgreatpotentialinefficiency ,low voltage ,large area ,lightweight ,andfull colorflat paneldisplays[1,2 ] .Forfull colordis plays ,itisnecessarytohaveefficientred ,green ,andblueemitterswithappropriatechromaticity .Bycom parisonwiththehighperformanceofblueandgreenOLEDs ,theperformanceandpurechromaticityofredOLEDsarestillrelativelypoor .UsuallyredOLEDsareimprovedbydopingreddyesintohostmaterialswit…  相似文献   

Designing Curriculum-Based Mathematics Professional Development for Kindergarten Teachers     

Drew Polly  Christie S. Martin  Jennifer R. McGee  Chuang Wang  Richard G. Lambert  David K. Pugalee 《Early Childhood Education Journal》2017,45(5):659-669

This study examines the influence of a year-long mathematics professional development program on Kindergarten teachers’ beliefs, content knowledge, instructional practices, and their students’ achievement. The professional development program is grounded in the theoretical construct of learner-centered professional development and focuses on supporting teachers’ integration of standards-based pedagogies aligned with the Common Core State Standards in Mathematics. Data analysis included examining 15 Kindergarten teachers’ mathematics content knowledge, their beliefs about mathematics, their enactment of student-centered pedagogies, and student achievement on curriculum-based assessments. Findings indicated that teachers adopted more student-centered pedagogies and embraced more student-centered beliefs about mathematics teaching during their time in the project. Further, Kindergarten teachers also demonstrated gains in their mathematical content knowledge, and those content knowledge gains were linked to gains in student achievement.  相似文献   

Improving content area reading comprehension of Spanish speaking English learners in Grades 4 and 5 using web-based text structure instruction     

Kausalai Wijekumar  Bonnie J. F. Meyer  Puiwa Lei  Anita C. Hernandez  Diane L. August 《Reading and writing》2018,31(9):1969-1996

Reading and comprehending content area texts is important for academic and professional success as well as life skills necessary to maintain good health and quality lifestyle. Spanish speaking English language learners have shown poor performance on high-stakes assessments in reading comprehension. The number of Spanish speaking English learners (ELs) in our schools continues to increase at a fast pace, and therefore it is imperative that we address their reading comprehension needs swiftly and effectively. The text structure strategy has shown positive results on comprehension outcomes in many research studies with students at Grades 2, 4, 5, and 7. This study is the first implementation of instruction about the text structure strategy expressly designed to accommodate the linguistic and comprehension needs of Spanish speaking ELs in Grades 4 and 5. Strategy instruction on the web for English learners (SWELL) was designed to deliver instruction about the text structure strategy to Spanish speaker English learners. A randomized controlled study with pre and post-tests was conducted with 14 classrooms at fourth-grade and 17 classrooms at fifth-grade in high poverty schools where over 85% of students were Spanish speaking bilinguals or ELs. Analysis of data using multi-level models show moderate to large-effects favoring the students in the SWELL classrooms over the business as usual control classrooms on important measures such as a standardized reading comprehension test and main idea and cloze tasks. This research has practical implications for the use of web-based tools to provide high-quality and supportive instruction to improve Spanish speaking ELs reading comprehension skills.  相似文献   

Myricetin protects against diet-induced obesity and ameliorates oxidative stress in C57BL/6 mice     

Hong-ming Su  Li-na Feng  Xiao-dong Zheng  Wei Chen 《Journal of Zhejiang University. Science. B》2016,17(6):437-446

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Timothy Richard’s vision: Education and reform in China, 1880–1910     

Limin Bai 《Frontiers of Education in China》2016,11(1):117-118

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CIDE gene expression in adipose tissue,liver, and skeletal muscle from obese and lean pigs     

Yue-qin Qiu  Xue-fen Yang  Xian-yong Ma  Yun-xia Xiong  Zhi-mei Tian  Qiu-li Fan  Li Wang  Zong-yong Jiang 《Journal of Zhejiang University. Science. B》2017,18(6):492-500

The expression of the cell death-inducing DNA fragmentation factor α-like effector (CIDE) family including Cidea, Cideb, and Cidec was significantly increased in mouse and human models of obesity. However, there was less information on these genes’ expression in pigs. Here, we hypothesized that different fat accumulation between lean (Duroc×Landrace×Yorkshire gilts, DLY) and obese (Lantang) pigs was attributed to porcine CIDE-modulating lipid metabolism. Our data showed that Cidea and Cidec were expressed at a high level in adipose tissue, and at a relatively high level in skeletal muscle, whereas Cideb was mainly expressed in the liver in both breeds of pig. Lantang pigs had higher white adipose and skeletal muscle Cidea and Cidec mRNA abundance, and hepatic and muscle Cideb mRNA than DLY pigs. Lipid metabolism-related genes including sterol regulatory element binding protein 1c (SREBP-1c), hepatocyte nuclear factor-4α (HNF-4α), peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α), fatty acid synthase (FASN), diacylglycerol O-acyltransferase 1 (DGAT1), and DGAT2 showed a higher expression level in adipose tissue from obese pigs than in that from lean pigs. Lantang pigs exhibited higher mRNA abundance for liver SREBP-1c, HNF-4α, and PGC-1α, and higher skeletal muscle SREBP-1c, HNF-4α, PGC-1α, and DGAT2 expression, as compared with DLY pigs. However, the perlipin2 mRNA levels in adipose tissues, liver, and skeletal muscle were significantly lower in obese pigs than in their lean counterparts. Furthermore, plasma non-esterified fatty acid (NEFA), glucose, and triacylglycerol (TAG) levels were greater in obese pigs than in lean pigs. Finally, data from correlation analysis further found that CIDE mRNA expression was positively correlated with back fat thickness (BFT), abdominal fat mass (AFM), and the levels of NEFA, TAG, and glucose in the two breeds. Collectively, these data revealed that the porcine CIDEs possibly modulated lipid metabolism and contributed to the development of fat deposition and obesity in Lantang pigs.  相似文献   

Conversion of CO<Subscript>2</Subscript> to useful substances with composite iron,nickel, and copper catalysts     

Takashi Sagawa 《浙江大学学报(A卷英文版)》2018,19(1):80-85

Composite materials of Fe/Al₂O₃, which consist of small particles of iron supported by thermally stable alumina even at 500–700 °C, have been widely used in the water-gas shift reaction for natural gas reforming. Therefore, Fe/Al₂O₃ is one of the promising candidates for re-transformation of exhausted CO₂ into fuels such as alcohols and hydrocarbons. The development of a CO₂ reforming system using the composite materials of Fe/Al₂O₃ through CO₂ reduction to CO, dissociation of water into hydrogen, and methanol synthesis has been investigated. It was found that dry and steam (i.e. wet) reforming of CO₂ produced almost the same amount of CO. At a temperature above 500 °C, maximal and saturated yields of CO and H₂ from CO₂ and water were obtained. However, this CO₂ reforming system requires higher-pressure conditions from several tens to hundreds standard atmospheric pressure in order to achieve high yield and selectivity for methanol production. In this study we developed the modified CO₂ reforming system by the utilization of Ni and/or Cu instead of Fe in order to obtain other types of useful products such as CO, CH₄, and carbon, more efficiently and selectively under atmospheric pressure. When Ni or Cu was used, conversion of CO₂ was reduced to 76%, while 9% of methane was detected in the case of Ni. On the other hand, though the CO₂ conversion reduced half of the Fe, the selectivity of CO from CO₂ increased to 95% in the case of Cu.  相似文献   

Conversations with Innovators in Learning and Technology: E. Jane Davidson     

Fredrick W. BakerIII 《TechTrends》2017,61(5):411-414

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Numerical investigation of cavitating flow behind the cone of a poppet valve in water hydraulic system   总被引：2，自引：0，他引：2  

高红  傅新  杨华勇  Tsukiji Tetsuhiro 《浙江大学学报(A卷英文版)》2002,3(4):395-400

Computational Fluid Dynamics (CFD) simulations of cavitating flow through water hydraulic poppet valves were performed using advanced RNGk-epsilon turbulence model. The flow was turbulent, incompressible and unsteady, for Reynolds numbers greater than 43000. The working fluid was water, and the structure of the valve was simplified as a two dimensional axisymmetric geometrical model. Flow field visualization was numerically achieved. The effects of inlet velocity, outlet pressure, opening size as well as poppet angle on cavitation intensity in the poppet valve were numerically investigated. Experimental flow visualization was conducted to capture cavitation images near the orifice in the poppet valve with 30° poppet angle using high speed video camera. The binary cavitating flow field distribution obtained from digital processing of the original cavitation image showed a good agreement with the numerical result. Project supported by the National Natural Science Foundation of China (No. 59835160) and Scientific Research Foundation for Returned Overseas Chinese Scholars, State Education Ministry of China (No. 50175097)  相似文献