期刊文献+
共找到40,338篇文章
< 1 2 250 >
每页显示 20 50 100
Effects of spot size on the operation mode of Ga As photoconductive semiconductor switch employing extrinsic photoconductivity 被引量:1
1
作者 韦金红 李嵩 +5 位作者 陈红 曾凡正 贾成林 付泽斌 葛行军 钱宝良 《Plasma Science and Technology》 SCIE EI CAS CSCD 2024年第5期91-99,共9页
To guide the illuminating design to improve the on-state performances of gallium arsenide(GaAs)photoconductive semiconductor switch(PCSS),the effect of spot size on the operation mode of GaAsPCSS based on a semi-insul... To guide the illuminating design to improve the on-state performances of gallium arsenide(GaAs)photoconductive semiconductor switch(PCSS),the effect of spot size on the operation mode of GaAsPCSS based on a semi-insulating wafer with a thickness of 1 mm,triggered by a 1064-nm extrinsic laser beam with the rectangular spot,has been investigated experimentally.It is found that the variation of the spot size in length and width can act on the different parts of the output waveform integrating the characteristics of the linear and nonlinear modes,and then significantly boosts the PCSS toward different operation modes.On this basis,a two-channel model containing the active and passive parts is introduced to interpret the relevant influencing mechanisms.Results indicate that the increased spot length can peak the amplitude of static domains in the active part to enhance the development of the nonlinear switching,while the extended spot width can change the distribution of photogenerated carriers on both parts to facilitate the linear switching and weaken the nonlinear switching,which have been proved by comparing the domain evolutions under different spot sizes. 展开更多
关键词 GaAs PCSS operation mode spot size on-state performances two-channel model domain evolution
下载PDF
6-48月龄婴幼儿Spot屈光度异常结果分析
2
作者 张永强 艾咏归 +2 位作者 刘晓慧 杨孝颖 何娇 《国际眼科杂志》 CAS 2024年第7期1162-1164,共3页
目的:分析6-48月龄婴幼儿Spot屈光异常情况,为婴幼儿屈光不正矫正及弱视早期防治提供依据。方法:对6-48月龄婴幼儿使用Spot双目视力筛查仪进行自然状况下验光,根据Spot屈光筛查仪4岁以下儿童转诊标准,收集屈光异常婴幼儿临床资料;使用... 目的:分析6-48月龄婴幼儿Spot屈光异常情况,为婴幼儿屈光不正矫正及弱视早期防治提供依据。方法:对6-48月龄婴幼儿使用Spot双目视力筛查仪进行自然状况下验光,根据Spot屈光筛查仪4岁以下儿童转诊标准,收集屈光异常婴幼儿临床资料;使用睫状肌麻痹剂视网膜检影验光,并对验光结果进行统计分析。结果:根据转诊标准共收集Spot屈光度异常婴幼儿168例336眼。其中远视及散光异常占比高,分别为38.4%和28.6%,而近视占比低(12.2%)。168例Spot屈光度异常婴幼儿中,屈光参差(≥1.00 D)共90例,其中散光性屈光参差41例(45.6%)、远视性屈光参差33例(36.7%),近视性屈光参差16例(17.8%)占比最少。共109例Spot屈光度异常婴幼儿完成睫状肌麻痹剂视网膜检影验光。对其Spot屈光度与睫状肌麻痹后检影验光结果差异及相关性分析结果显示,两者散光度差异为0.34±0.64 D(P<0.001),远视度差异为-2.10±1.27 D(P<0.001),近视度差异为-0.43±0.91 D(P=0.023);虽然二者结果存在统计学差异,但二者散光度、远视度及近视度均呈正相关(r=0.694、0.762、0.909)。结论:6-48月龄婴幼儿Spot屈光异常主要以散光、远视异常和屈光参差为主,近视异常较少;对Spot筛查异常者应进一步睫状肌麻痹剂视网膜检影验光,给予配镜矫正,有效防止婴幼儿屈光性弱视。 展开更多
关键词 spot视力筛查 婴幼儿 屈光
下载PDF
Analysis and construction of evaluation index system of inter-provincial electricity spot markets
3
作者 Hao Yue Yu Zhang +5 位作者 Jiahao Guo Yang Hu Chengmei Wei Heping Jia Dunnan Liu Dunjian Xie 《Global Energy Interconnection》 EI CSCD 2024年第6期697-706,共10页
Because of the contradiction between the scale of new energy installations and the continuous load growth in the central and eastern regions of China,the balance problems of the electricity market are becoming increas... Because of the contradiction between the scale of new energy installations and the continuous load growth in the central and eastern regions of China,the balance problems of the electricity market are becoming increasingly prominent,and it is urgent to solve such problems through inter-provincial electricity spot markets.First,the development history and construction status of the inter-provincial electricity spot market are summarized;second,the mechanism design of the inter-provincial electricity spot market is sorted out in terms of the market operation framework,transaction declaration,and clearing methods;subsequently,the evaluation index system of the inter-provincial electricity spot market is constructed,including four themes of electricity mutual aid and support,new energy consumption,economic benefits of market-based allocation,and social benefits of market-based allocation;finally,the operation of the inter-provincial electricity spot market is comprehensively analyzed by the algorithm based on the market operation data of 2022,which proves the feasibility and practicality of the proposed index system. 展开更多
关键词 Electricity market spot market Inter-provincial spot market Evaluation index system
下载PDF
Numerical Study of Flow Features Around Submerged Circular and Square Piles at Flat and Scoured Beds Using OpenFOAM
4
作者 WANG Chaolin WU Guoxiang +5 位作者 WANG Dianhe DU Shengtao ZHANG Zhiyong JIN Heng ZHU David Z. LIANG Bingchen 《Journal of Ocean University of China》 SCIE CAS CSCD 2024年第4期897-914,共18页
Elucidating the flow features around piles in local scouring processes is crucial for studies of local scouring mechanisms and scour depth estimates.This study details the flow turbulence characteristics of two submer... Elucidating the flow features around piles in local scouring processes is crucial for studies of local scouring mechanisms and scour depth estimates.This study details the flow turbulence characteristics of two submerged piles that are determined by solving the Navier-Stokes equations with the improved delayed detached eddy simulation model.This model is verified by comparing experimental and numerical results for hydrodynamic parameters with the literature for both square-crossing piles(SCPs)and circular-crossing piles(CCPs).Original topographies of flat and scoured beds(i.e.,the initial and equilibrium scouring stages)are based on experimental results obtained by the authors in the present paper.SCP and CCP flow features in the scouring process are discussed.The results indicate that during the scouring process,the time-averaged drag coefficient and root mean square(rms)of the lift coefficient increase linearly in the CCP test,while the rms of the lift coefficient in the SCP test decreases linearly.Moreover,the minimum pressure coefficient is always located in the upstream corners in the SCP case but moves from 72.5°to 79.5°when the scour hole is completely developed in the CCP case.Downward flow behind the pile,which is generated by separated boundary layers above the top face of the pile,can reach the sand bed and turn the separated shear layers into patches of small vortices in the near-wake regions.Thus,the high shear stress zones are mainly at the scour edges under scoured-bed conditions. 展开更多
关键词 flat bed scoured bed local scour OPENFOAM bed shear stress
下载PDF
Experimental observation of Fermi-level flat band in novel kagome metal CeNi_(5)
5
作者 陈学智 王乐 +7 位作者 张帅 张任杰 程以伟 胡裕栋 孟承诺 刘正太 吕佰晴 黄耀波 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第8期467-472,共6页
Kagome materials are a class of material with a lattice structure composed of corner-sharing triangles that produce various exotic electronic phenomena,such as Dirac fermions,van Hove singularities,and flat bands.Howe... Kagome materials are a class of material with a lattice structure composed of corner-sharing triangles that produce various exotic electronic phenomena,such as Dirac fermions,van Hove singularities,and flat bands.However,most of the known kagome materials have a flat band detached from the Fermi energy,which limits the investigation of the emergent flat band physics.In this work,by combining soft x-ray angle-resolved photoemission spectroscopy(ARPES)and the first-principles calculations,the electronic structure is investigated of a novel kagome metal CeNi_(5) with a clear dispersion along the kz direction and a Fermi level flat band in theΓ–K–M–Γplane.Besides,resonant ARPES experimental results indicate that the valence state of Ce ions is close to 4^(+),which is consistent with the transport measurement result.Our results demonstrate the unique electronic properties of CeNi_(5) as a new kagome metal and provide an ideal platform for exploring the flat band physics and the interactions between different types of flat bands by tuning the valence state of Ce ions. 展开更多
关键词 ARPES kagome lattice band structure flat band
下载PDF
Layered kagome compound Na_(2)Ni_(3)S_(4)with topological flat band
6
作者 叶君耀 林益浩 +4 位作者 王浩哲 宋志达 冯济 谢韦伟 贾爽 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第5期153-159,共7页
We report structural and electronic properties of Na_(2)Ni_(3)S_(4),a quasi-two-dimensional compound composed of alternating layers of[Ni_(3)S_(4)]^(2-)and Na^(+).The compound features a remarkable Ni-based kagome lat... We report structural and electronic properties of Na_(2)Ni_(3)S_(4),a quasi-two-dimensional compound composed of alternating layers of[Ni_(3)S_(4)]^(2-)and Na^(+).The compound features a remarkable Ni-based kagome lattice with a square planar configuration of four surrounding S atoms for each Ni atom.Magnetization and electrical measurements reveal a weak paramagnetic insulator with a gap of about 0.5 eV.Our band structure calculation highlights a set of topological flat bands of the kagome lattice derived from the rotated dxz-orbital with C_(3)+T symmetry in the presence of crystal-field splitting. 展开更多
关键词 kagome lattice flat band
下载PDF
Observation of flat-band localized state in a one-dimensional diamond momentum lattice of ultracold atoms
7
作者 曾超 石悦然 +5 位作者 毛一屹 武菲菲 谢岩骏 苑涛 戴汉宁 陈宇翱 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第1期212-217,共6页
We investigated the one-dimensional diamond ladder in the momentum lattice platform. By inducing multiple twoand four-photon Bragg scatterings among specific momentum states, we achieved a flat band system based on th... We investigated the one-dimensional diamond ladder in the momentum lattice platform. By inducing multiple twoand four-photon Bragg scatterings among specific momentum states, we achieved a flat band system based on the diamond model, precisely controlling the coupling strength and phase between individual lattice sites. Utilizing two lattice sites couplings, we generated a compact localized state associated with the flat band, which remained localized throughout the entire time evolution. We successfully realized the continuous shift of flat bands by adjusting the corresponding nearest neighbor hopping strength, enabling us to observe the complete localization process. This opens avenues for further exploration of more complex properties within flat-band systems, including investigating the robustness of flat-band localized states in disordered flat-band systems and exploring many-body localization in interacting flat-band systems. 展开更多
关键词 diamond lattice flat band momentum lattice localized state
下载PDF
Laser-induced breakdown spectroscopy as a method for millimeter-scale inspection of surface flatness
8
作者 Jinrui YE Yaju LI +8 位作者 Zhao ZHANG Xinwei WANG Kewei TAO Qiang ZENG Liangwen CHEN Dongbin QIAN Shaofeng ZHANG Lei YANG Xinwen MA 《Plasma Science and Technology》 SCIE EI CAS CSCD 2024年第9期148-155,共8页
A non-contact method for millimeter-scale inspection of material surface flatness via Laser-Induced Breakdown Spectroscopy(LIBS)is investigated experimentally.The experiment is performed using a planished surface of a... A non-contact method for millimeter-scale inspection of material surface flatness via Laser-Induced Breakdown Spectroscopy(LIBS)is investigated experimentally.The experiment is performed using a planished surface of an alloy steel sample to simulate its various flatness,ranging from 0 to 4.4 mm,by adjusting the laser focal plane to the surface distance with a step length of 0.2 mm.It is found that LIBS measurements are successful in inspecting the flatness differences among these simulated cases,implying that the method investigated here is feasible.It is also found that,for achieving the inspection of surface flatness within such a wide range,when univariate analysis is applied,a piecewise calibration model must be constructed.This is due to the complex dependence of plasma formation conditions on the surface flatness,which inevitably complicates the inspection procedure.To solve the problem,a multivariate analysis with the help of Back-Propagation Neural Network(BPNN)algorithms is applied to further construct the calibration model.By detailed analysis of the model performance,we demonstrate that a unified calibration model can be well established based on BPNN algorithms for unambiguous millimeter-scale range inspection of surface flatness with a resolution of about 0.2 mm. 展开更多
关键词 laser-induced breakdown spectroscopy machine learning surface flatness
下载PDF
T-SPOT联合颗粒酶B阳性Ts淋巴细胞对成人结核病诊断的价值
9
作者 戴乾滨 陈桉军 +3 位作者 朱清 魏丹丹 刘蓬 刘洋 《标记免疫分析与临床》 CAS 2024年第8期1454-1458,1534,共6页
目的探讨结核感染T细胞斑点试验(T-SPOT.TB)联合颗粒酶B(GrB)+CD8^(+)T淋巴细胞在诊断结核病中的价值。方法选取南昌大学第一附属医院2021年2月至2022年3月疑似结核病患者212例,所有患者均保留T-SPOT结果,流式细胞仪检测外周血中T淋巴... 目的探讨结核感染T细胞斑点试验(T-SPOT.TB)联合颗粒酶B(GrB)+CD8^(+)T淋巴细胞在诊断结核病中的价值。方法选取南昌大学第一附属医院2021年2月至2022年3月疑似结核病患者212例,所有患者均保留T-SPOT结果,流式细胞仪检测外周血中T淋巴细胞亚群及其穿孔素和GrB的表达,根据出院最终诊断分为结核病组和非结核病组,比较两组间T-SPOT斑点数和淋巴细胞亚群及其穿孔素和GrB表达差异,ROC曲线分析ESAT-6斑点数,CFP-10斑点数,结核特异性抗原(TBAg)与植物血凝素(PHA)斑点数的比值(TBAg/PHA)(ESAT-6/PHA和CFP-10/PHA中较大的一个),GrB^(+)Ts(CD8^(+)T)及“结核比值”[TBAg/(PHA*GrB^(+)Ts)]的诊断效能。结果GrB^(+)Ts细胞百分比在结核组中显著高于非结核组(44.95±2.98 vs 33.49±1.87,P<0.05),而总T细胞、穿孔素+T细胞,GrB^(+)T细胞,Ts细胞和穿孔素+Ts细胞百分比差异无统计学意义(P>0.05);非结核组T-SPOT.TB阳性率为51.85%,明显低于结核组的92%,且结核组的A抗原斑点数及B抗原斑点数显著大于非结核组(P<0.05),ROC曲线显示A抗原诊断结核病的灵敏度和特异性分别为80.0%和56.8%,曲线下面积(AUC)为0.748,约登指数为0.368;B抗原的灵敏度和特异性为分别62.0%和77.8%,AUC为0.758,约登指数为0.398;A抗原+B抗原灵敏度和特异性为72.0%和74.1%,AUC为0.796,约登指数为0.461;结核组的TBAg/PHA比率要显著高于非结核组(1.21±0.17 vs 0.26±0.02,P<0.001)以0.59为cut-off值时,诊断结核病的灵敏度和特异性分别为66%和91.4%,AUC高达0.852,约登指数为0.574;结核组的“结核比值”要显著高于非结核组(4.58±0.87 vs 1.71±0.24,P<0.01),以1.24为cut-off值时,诊断结核病的灵敏度和特异性分别为82.0%和72.2%,AUC为0.794,约登指数为0.542。结论应用TBAg/PHA比率和TBAg/(PHA*GrB^(+)Ts)比值诊断结核病的效能要优于常规的T-SPOT检测,两者结合使用对结核病诊断可能具有重要价值。 展开更多
关键词 结核 T-spot TBAg/PHA比率 TBAg/(PHA*Ts颗粒酶B)比值
下载PDF
Effects of Poria cocos polysaccharide on growth performance,physiological parameters,and lipid metabolism of spotted sea bass Lateolabrax maculatus
10
作者 Jing LU Zhangfan HUANG +2 位作者 Youling YE Anle XU Zhongbao LI 《Journal of Oceanology and Limnology》 SCIE CAS CSCD 2024年第1期316-331,共16页
The aquaculture industry has developed significantly over the past few decades and has had a substantial impact on the global food supply and marine fisheries resources.However,some problems arise behind the scenes du... The aquaculture industry has developed significantly over the past few decades and has had a substantial impact on the global food supply and marine fisheries resources.However,some problems arise behind the scenes due to excessive intensive farming,such as slow animal growth,frequent disease,and lipid metabolism disorders.These problems have limited the sustainable development of the aquaculture industry,and a continuable solution is required.The use of fungal polysaccharide appears to provide a solution to these problems.Therefore,different supplemented levels of Poria cocos polysaccharide(PCP)(0,0.4,0.8,1.2,1.6,and 2.0 g/kg,respectively)were fed to spotted sea bass(Lateolabrax maculatus)in similar size(30.28±0.18 g)in current study.The effects of PCP on growth,physiological parameters,and lipid metabolism of spotted sea bass were investigated after a 4-week rearing period.Results showed,fish with PCP intake presented a significantly higher weight gain,specific growth rate,and a significantly lower feed conversion ratio.Significantly higher trypsin activity in liver and intestine were observed in fish with PCP intake.The superoxide dismutase activity in serum and liver of fish with PCP intake were significantly improved,while significantly higher serum total antioxidant capacity and hepatic catalase activity were also observed.However,no significant differences in lysozyme and alkaline phosphatase activity were evident among groups.Fish with PCP intake showed a significantly lower total cholesterol,but no noteworthy change in triglyceride and lipid-metabolismrelated genes expression were observed among groups.Results indicated that intake of PCP has a positive effect on growth and antioxidant capacity of spotted sea bass,but seems to have a limited effect on the non-specific immunity and lipid metabolism of spotted sea bass.Based on the regression analysis results,1.4 g/kg of PCP is the optimal dose for spotted sea bass in size(30.28±0.18 g). 展开更多
关键词 spotted sea bass Poria cocos POLYSACCHARIDE GROWTH lipid metabolism
下载PDF
Development characteristics and controlling factors of fractures in lacustrine shale and their geological significance for evaluating shale oil sweet spots in the third member of the Shahejie Formation in the Qikou Sag, Bohai Bay Basin
11
作者 Xu Zeng Tao Yang +5 位作者 Jian-Wei Feng Cong-Sheng Bian Ming Guan Wei Liu Bing-Cheng Guo Jin Dong 《Petroleum Science》 SCIE EI CAS CSCD 2024年第2期791-805,共15页
Natural fractures are critical for shale oil and gas enrichment and development. Due to the extremely high heterogeneity of shale, the factors controlling the formation of internal fractures, especially horizontal fra... Natural fractures are critical for shale oil and gas enrichment and development. Due to the extremely high heterogeneity of shale, the factors controlling the formation of internal fractures, especially horizontal fractures, remain controversial. In this study, we integrate thin section analysis and microcomputed tomography(CT) data from several lacustrine shale samples from the third member(Es3) of the Shahejie Formation, Qikou Sag, Bohai Bay Basin, to assess the fractures in detail. The goal is to reveal the development characteristics, controlling factors, and geological significance for evaluating sweet spots in a shale oil play. The fractures in the Es3contain high-angle structural and horizontal bed-parallel fractures that are mostly shear and extensional. Various factors influence fracture development,including lithofacies, mineral composition, organic matter content, and the number of laminae. Structural fractures occur predominantly in siltstone, whereas bed-parallel fractures are abundant in laminated shale and layered mudstone. A higher quartz content results in higher shale brittleness, causing fractures, whereas the transformation between clay minerals contributes to the development of bedparallel fractures. Excess pore pressure due to hydrocarbon generation and expulsion during thermal advance can cause the formation of bed-parallel fractures. The density of the bed-parallel and structural fractures increases with the lamina density, and the bed-parallel fractures are more sensitive to the number of laminae. The fractures are critical storage spaces and flow conduits and are indicative of sweet spots. The laminated shale in the Es3with a high organic matter content contains natural fractures and is an organic-rich, liquid-rich, self-sourced shale play. Conversely, the siltstone, massive mudstone, and argillaceous carbonate lithofacies contain lower amounts of organic matter and do not have bed-parallel fractures. However, good reservoirs can form in these areas when structural fractures are present and the source, and storage spaces are separated. 展开更多
关键词 FRACTURES Development characteristics Controlling factors Shale oil Sweet spot
下载PDF
Evaluation of the seismic behavior of reinforced concrete structures with flat slab-column gravity frame and shear walls through nonlinear analysis methods
12
作者 M.A.Najafgholipour S.Heidarian Radbakhsh E.Erfani 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2024年第3期713-726,共14页
This paper presents an investigation of the seismic behavior of reinforced concrete(RC)structures in which shear walls are the main lateral load-resisting elements and the participation of flat slab floor systems is n... This paper presents an investigation of the seismic behavior of reinforced concrete(RC)structures in which shear walls are the main lateral load-resisting elements and the participation of flat slab floor systems is not considered in the seismic design procedure.In this regard,the behavior of six prototype structures(with different heights and plan layouts)is investigated through nonlinear static and time history analyses,implemented in the OpenSees platform.The results of the analyses are presented in terms of the behavior of the slab-column connections and their mode of failure at different loading stages.Moreover,the global response of the buildings is discussed in terms of some parameters,such as lateral overstrength due to the gravity flat slab-column frames.According to the nonlinear static analyses,in structures in which the slab-column connections were designed only for gravity loads,the slab-column connections exhibited a punching mode of failure even in the early stages of loading.However,the punching failure was eliminated in structures in which a minimum transverse reinforcement recommended in ACI 318(2019)was provided in the slabs at joint regions.Furthermore,despite neglecting the contribution of gravity flat slab-column frames in the lateral load resistance of the structures,a relatively significant overstrength was imposed on the structures by the gravity frames. 展开更多
关键词 RC flat slab-column frames seismic behavior nonlinear analysis time history analysis
下载PDF
Variations of phyllosphere microorganisms in asymptomatic and tobacco brown spot leaves before and after spraying 12% difenoconazole + fluxapyroxad SC
13
作者 LI Tong WANG Hancheng +6 位作者 YE Guo WANG Qing NGANGUEM NZALLE Yranney Brice WANG Feng CAI Liuti FENG Ruichao ZHANG Songbai 《农药学学报》 CAS CSCD 北大核心 2024年第5期932-948,共17页
12%difenoconazole+fluxapyroxad SC(commercial name:Jiangong)was first released by BASF in China in 2016.It has been registered to control many diseases,including pear scab,apple Alternaria leaf spot,tomato early blight... 12%difenoconazole+fluxapyroxad SC(commercial name:Jiangong)was first released by BASF in China in 2016.It has been registered to control many diseases,including pear scab,apple Alternaria leaf spot,tomato early blight,cucumber powdery mildew,etc.This study evaluated the bioactivity of Jiangong against Alternaria alternata and explored variations of phyllosphere microorganisms in both asymptomatic and tobacco brown spot leaves at different persistence periods(0,5,10,and 15 days post-fungicide application)using high-throughput sequencing technology.The results indicated that Jiangong effectively inhibited mycelial growth(average EC_(50) value of 0.51μg/mL),conidia germination(average EC_(50) value of 3.47μg/mL),and the carbon metabolism of A.alternata.Both asymptomatic and symptomatic leaves presented complex microbial communities.Higher fungal diversity was noted in asymptomatic leaves,while higher bacterial diversity was found in symptomatic leaves.After application,the diversity and abundance of microbial community structures in both types of leaves changed over time.Fungal microbiome communities showed greater sensitivity than bacterial groups,with the microbiome communities of asymptomatic leaves being more affected than those of symptomatic leaves.Fungal community diversity decreased for both symptomatic and asymptomatic leaves after 5 days of application,while the diversity of fungal community in symptomatic leaves showed an upward trend after 10 days of application.Meanwhile,bacterial community diversity increased in both symptomatic and asymptomatic leaves after 5 days of application but then declined in asymptomatic leaves after 15 days.The abundance of the dominant function group of phyllosphere bacteria(metabolism,genetic information processing,environmental information processing)was not affected by the application of Jiangong.However,the abundance of the dominant function group of phyllosphere fungi(animal pathogen-endophyte-wood saprotroph,endophyte-plant pathogen,plant pathogen-undefined saprotroph)was significantly affected by the application of Jiangong,and high variation was found in symptomatic leaves than that of asymptomatic leaves.The application of Jiangong-induced alterations in the community structure of the tobacco phyllosphere microbiome provides a basis for future tobacco brown spot control strategies based on phyllospheric microecology. 展开更多
关键词 tobacco brown spot DIFENOCONAZOLE fluxapyroxad microorganism communities diversity high-throughput sequencing
下载PDF
A More Accurate Determination of the Magnitude of Cosmic Inflation in the Big Bang Model
14
作者 Slobodan Spremo 《Journal of High Energy Physics, Gravitation and Cosmology》 CAS 2024年第1期27-30,共4页
According to our hypothesis, at the very beginning of the Big Bang, a hyperenergetic spherical wave was created. We described its characteristics in our previous work, and the present work is based on them. Logically,... According to our hypothesis, at the very beginning of the Big Bang, a hyperenergetic spherical wave was created. We described its characteristics in our previous work, and the present work is based on them. Logically, we saw that in cosmic inflation the frequency of such a wave would decrease sharply. Based on the temperature that prevailed immediately after inflation according to the hot Big Bang model, we determined a measure of the size of the inflation in this model, in accordance with our hypothesis. 展开更多
关键词 flat Space and Time Hyperenergetic Spherical Wave Primary Particles Quantum of Speed
下载PDF
Evaluation of Resistance of Different Kiwifruit Varieties (Lines) to Canker Disease and Brown Spot Disease
15
作者 Wenwen Su Chongpei Zheng +5 位作者 Zhencheng Han Chunguang Ren Di Wu Tao Li Yi Yang Weijie Li 《Phyton-International Journal of Experimental Botany》 SCIE 2024年第6期1249-1261,共13页
Kiwifruit canker and brown spot are significant diseases affecting kiwis,caused by Pseudomonas syringae patho-genic variations(Pseudomonas syringae pv.Actinidiae(Psa))and Corynesporapolytica(Corynespora cassiicola).At ... Kiwifruit canker and brown spot are significant diseases affecting kiwis,caused by Pseudomonas syringae patho-genic variations(Pseudomonas syringae pv.Actinidiae(Psa))and Corynesporapolytica(Corynespora cassiicola).At present,the research on canker disease and brown spot disease mainly focuses on the isolation and identification of pathogenic bacteria,drug control,resistance gene mining and functional verification.Practice has proved that breeding disease resistant varieties are an effective method to control canker disease and brown spot disease.However,most existing cultivars lack genes for canker and brown spot resistance.Wild kiwifruit resources in nat-ure exhibit extensive genetic diversity due to prolonged natural selection,containing numerous resistance genes.But,due to insufficient understanding of the resistance of most kiwifruit varieties(lines)to canker disease and brown spot disease,some high-quality resources have not been fully utilized.The incidence of canker and brown spot of 18 kiwifruit cultivars(lines)was measured by inoculating isolated branches and leaves,and their resistance to canker and brown spot was analyzed according to the length,disease index,mean diameter,and systematic clustering.The results were as follows:Among 18 different kiwifruit varieties(lines)for canker disease,there were two highly resistant materials,eight disease-resistant materials,four disease-susceptible materials,and two highly susceptible materials.Moreover,regarding brown spot disease,there were one highly resistant material,five dis-ease-resistant materials,four susceptible materials,and three highly susceptible materials.Furthermore,four resources were resistant to both diseases.The outcomes provided a theoretical basis for breeding kiwifruit against canker and brown spot. 展开更多
关键词 KIWIFRUIT canker disease brown spot resistance evaluation
下载PDF
Detour for the inexperienced? Migration count data suggest mostly juvenile Greater Spotted Eagles appear in coastal peninsulas in China
16
作者 Xu Shi Xiaoping Wang +2 位作者 Qian Wei Qiwei Lin Lei Zhu 《Avian Research》 SCIE CSCD 2024年第2期249-254,共6页
Soaring bird migration often relies on suitable terrain and airflow;therefore,route selection is vital for successful migration.While age and experience have been identified as key factor influencing migration route s... Soaring bird migration often relies on suitable terrain and airflow;therefore,route selection is vital for successful migration.While age and experience have been identified as key factor influencing migration route selection among soaring raptors in the African-Eurasian Flyway,how they shape the migration route of soaring raptors in East Asia is still largely unknown.In this study,we investigated potential variations in the routes and timing in autumn migration of juvenile and older soaring birds,using count data of Greater Spotted Eagles(Clanga clanga)from two coastal sites and two inland sites in China.From 2020 to 2023,we recorded a total of 340 individuals,with the highest site averaging over 90 individuals per autumn,making it one of the world’s top single-season counts and thus a globally important site for this species.We found that 82% and 61% records from coastal sites were juveniles,significantly higher than inland sites(15% and 24%).Juveniles at all four sites exhibited markedly earlier median passage time than non-juveniles,with brief overlapping in their main migration periods.Both coastal sites are located on the tip of peninsulas stretching southwest,requiring long overwater flights if crossing the Bohai Bay or Beibu Gulf,which would be energetically demanding and increase mortality risk.Experienced individuals may have learned to avoid such terrain and subsequent detour,while juveniles are more prone to enter these peninsulas due to lack of experience and opportunities for social learning,or following other raptor species that are more capable of powered flight.Our findings highlight the importance of age and experience in migration route selection of large soaring birds. 展开更多
关键词 Clanga clanga East Asia Greater spotted Eagle JUVENILE Migration route Social learning
下载PDF
Thermodynamic Analysis and Optimization of Flat Plate Solar Collector Using TiO_(2)/Water Nanofluid
17
作者 Firas F.Qader Falah Z.Mohammed Barhm Mohamad 《Journal of Harbin Institute of Technology(New Series)》 CAS 2024年第4期61-73,共13页
To research solar energy's efficiency and environmental benefits,the thermal efficiency,exergy,and entropy of solar collectors were calculated.The experiment involved two glass-topped collectors,fluid transfer tub... To research solar energy's efficiency and environmental benefits,the thermal efficiency,exergy,and entropy of solar collectors were calculated.The experiment involved two glass-topped collectors,fluid transfer tubes,and aluminum heat-absorbing plates.Glass wool insulation minimized heat loss.A 0.5% TiO_(2)/Water nanofluid was created using a mechanical and ultrasonic stirrer.Results showed that solar radiation increased thermal efficiency until midday,reaching 48.48% for water and 51.23% for the nanofluid.With increasing mass flow rates from 0.0045 kg/s to 0.02 kg/s,thermal efficiency improved from 16.26% to 47.37% for water and from 20.65% to 48.76% for the nanofluid.Filtered water provided 380 W and 395 W of energy in March and April,while the nanofluid increased it to 395 W and 415 W during these months.Mass flow generated energy,and the Reynolds number raised entropy.The noon exergy efficiency for nanofluids was 50%-55%,compared to 30% for water.At noon,the broken exergy measured 877.53 W for the nanofluid and 880.12 W for water.In Kirkuk,Iraq,the 0.5% TiO_(2)/Water nanofluid outperformed water in solar collectors. 展开更多
关键词 ENERGY EXERGY entropy generation NANOFLUID flat plate solar collector
下载PDF
ToF-SIMS characterization of a bare-spot defect in a hot-dip galvanized boron-added steel sheet
18
作者 JIN Xinyan HONG Jufeng 《Baosteel Technical Research》 CAS 2024年第3期1-9,共9页
To determine the root cause of a bare-spot defect in a hot-dip galvanized boron-added steel sheet,we performed metallurgical characterizations using time-of-flight secondary ion mass spectrometry(ToF-SIMS)in addition ... To determine the root cause of a bare-spot defect in a hot-dip galvanized boron-added steel sheet,we performed metallurgical characterizations using time-of-flight secondary ion mass spectrometry(ToF-SIMS)in addition to glow discharge optical emission spectrometry,field-emission scanning electron microscopy(FE-SEM),and energy dispersive spectroscopy.Mn and B enrichments on the steel surface in the bare-spot area were detected through various methods.FE-SEM revealed external oxide nodules and zinc droplets,which indicated poor wettability.ToF-SIMS further revealed considerably more detailed lateral and depth distributions of Mn,B,and Al.The formation of external Mn-B compound oxides on the steel surface prior to hot dipping,which substantially deteriorated the wettability and prevented the formation of a Fe_(2)Al_(5)inhibition layer,resulted in the formation of a bare-spot defect.ToF-SIMS mapping of Al ion proved that a slight reaction still occurred between the dissolved Al in the molten zinc bath and steel substrate,although no evident Fe_(2)Al_(5)inhibition layer formed in the bare-spot area. 展开更多
关键词 bare spot selective oxidation galvanized steel ToF-SIMS
下载PDF
Research status and hotspots of tight junctions and colorectal cancer:A bibliometric and visualization analysis
19
作者 Hui-Min Li Yin Liu +5 位作者 Meng-Di Hao Xiao-Qing Liang Da-Jin Yuan Wen-Bin Huang Wen-Jie Li Lei Ding 《World Journal of Gastrointestinal Oncology》 SCIE 2024年第8期3705-3715,共11页
BACKGROUND Colorectal cancer(CRC)is the third most common cancer worldwide and the second leading cause of cancer-related death.Over the past two decades,numerous researchers have provided important evidence regarding... BACKGROUND Colorectal cancer(CRC)is the third most common cancer worldwide and the second leading cause of cancer-related death.Over the past two decades,numerous researchers have provided important evidence regarding the role of tight junction(TJ)proteins in the occurrence and progression of CRC.The causal relationship between the presence of specific TJ proteins and the development of CRC has also been confirmed.Despite the large number of publications in this field,a bibliometric study to review the current state of research and highlight the research trends and hotspots in this field has not yet been performed.AIM To analyze research on TJs and CRC,summarize the field’s history and current status,and predict future research directions.METHODS We searched the Science Citation Index Expanded database for all literature on CRC and TJs from 2001-2023.We used bibliometrics to analyze the data of these papers,such as the authors,countries,institutions,and references.Co-authorship,co-citation,and co-occurrence analyses were the main methods of analysis.CiteSpace and VOSviewer were used to visualize the results.RESULTS A total of 205 studies were ultimately identified.The number of publications on this topic has steadily increased since 2007.China and the United States have made the largest contributions to this field.Anticancer Research was the most prolific journal,publishing 8 articles,while the journal Oncogene had the highest average citation rate(68.33).Professor Dhawan P was the most prolific and cited author in this field.Co-occurrence analysis of keywords revealed that“tight junction protein expression”,“colorectal cancer”,“intestinal microbiota”,and“inflammatory bowel disease”had the highest frequency of occurrence,revealing the research hotspots and trends in this field.CONCLUSION This bibliometric analysis evaluated the scope and trends of TJ proteins in CRC,providing valuable research perspectives and future directions for studying the connection between the two.It is recommended to focus on emerging research hotspots,such as the correlations among intestinal microbiota,inflammatory bowel disease,TJ protein expression,and CRC. 展开更多
关键词 Colorectal cancer Tight junctions Bibliometric analysis Research trends Hot spots
下载PDF
Key geological factors governing sweet spots in the Wufeng-Longmaxi shales of the Sichuan Basin,China
20
作者 Zongquan Hu Zengqin Liu +4 位作者 Wei Du Zhenrui Bai Ruyue Wang Chuanxiang Sun Dongjun Feng 《Energy Geoscience》 EI 2024年第3期163-174,共12页
Production performance of the Wufeng-Longmaxi shales varies significantly among Fuling,Weirong,and Wulong fields in the Sichuan Basin.Total organic carbon(TOC)content,mineralogy,and organic matter(OM)pore characterist... Production performance of the Wufeng-Longmaxi shales varies significantly among Fuling,Weirong,and Wulong fields in the Sichuan Basin.Total organic carbon(TOC)content,mineralogy,and organic matter(OM)pore characteristics are investigated to identify key factors governing sweet spots.Siliceous shales with good preservation conditions in the Fuling Field exhibit large thickness,high TOC content and thin-section porosity(TSP),and well-developed OM macropores,thus high initial production and estimated ultimate recovery(EUR).Thin carbonate-containing siliceous shales with good preservation conditions in the Weirong Field feature medium-to-high TOC and well-developed OM macropores but low TSP,leading to high initial production but low EUR.Siliceous shales with poor preservation conditions in the Wulong Field are characterized by large thickness,high TOC,low TSP and poorly-developed OM macropores,causing low initial production and EUR.Both sedimentary and preservation conditions are intrinsic decisive factors of sweet spots,as they control the mineral composition,TOC,and OM macropore development.Deep-water shales in transgressive systems tracts(TSTs)exhibit better-developed OM macropores and greater TOC compared to highstand systems tracts(HSTs).OM macropores are most prevalent in siliceous shales,followed by carbonate-containing siliceous shales and then argillaceous shales.Furthermore,good preservation conditions are conducive to retain OM macropores with low pore aspect ratio(PAR).Comparison among the three fields shows that high-TOC silicious shales with good preservation conditions are the highest in TSP and EUR.Therefore,organic richness,lithofacies,and preservation conditions are the major factors which determine OM pore development,governing the sweet spots of the Wufeng-Longmaxi shales. 展开更多
关键词 Shale gas Organic matter pores Sweet spot Wufeng-Longmaxi shales Sichuan basin
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部