期刊文献+
共找到159,938篇文章
< 1 2 250 >
每页显示 20 50 100
Auxin-brassinosteroid crosstalk:Regulating rice plant architecture and grain shape
1
作者 Meidi Wu Jing Zhou +3 位作者 Qian Li Dunfan Quan Qingwen Wang Yong Gao 《The Crop Journal》 SCIE CSCD 2024年第4期953-963,共11页
Rice(Oryza sativa)plant architecture and grain shape,which determine grain quality and yield,are modulatedby auxin and brassinosteroid via regulation of cell elongation and proliferation.We review the signaltransducti... Rice(Oryza sativa)plant architecture and grain shape,which determine grain quality and yield,are modulatedby auxin and brassinosteroid via regulation of cell elongation and proliferation.We review the signaltransduction of these hormones and the crosstalk between their signals on the regulation of rice plantarchitecture and grain shape. 展开更多
关键词 AUXIN BRASSINOSTEROID Auxin-brassinosteroid crosstalk Plant architecture Grain shape
下载PDF
3shape Trios 3口内扫描和传统硅橡胶在牙体缺损修复中的失败原因分析
2
作者 李娜 《临床医学研究与实践》 2024年第9期85-88,共4页
目的分析并比较3shape Trios 3口内扫描和传统硅橡胶在牙体缺损修复中的失败原因,为临床取模以及口内扫描仪性能改善提供参考依据。方法回顾性分析2021年1月至2023年10月实施口腔固定修复治疗并返工的200例患者为研究对象,以取模方式将... 目的分析并比较3shape Trios 3口内扫描和传统硅橡胶在牙体缺损修复中的失败原因,为临床取模以及口内扫描仪性能改善提供参考依据。方法回顾性分析2021年1月至2023年10月实施口腔固定修复治疗并返工的200例患者为研究对象,以取模方式将其分为口扫组(n=97)和硅橡胶组(n=103)。口扫组给予3shape Trios 3口内扫描,硅橡胶组给予传统硅橡胶。比较两组在牙体缺损修复中的失败原因。结果两组的牙体缺损修复失败分布情况比较,差异具有统计学意义(P<0.05);口扫组中,龈下缺损修复失败占比高于龈上(P<0.05)。两组的龈下缺损修复失败原因比较,差异具有统计学意义(P<0.05)。结论相较于传统硅橡胶,3shape Trios 3口内扫描在龈上缺损修复中更有优势,但在龈下缺损修复中,硅橡胶应用效果更佳。 展开更多
关键词 3shape Trios 3口内扫描 硅橡胶 牙体缺损
下载PDF
基于Cross熵与改进麻雀搜索算法的图像分割模型
3
作者 黄蓉 陈倩诒 《计算机应用与软件》 北大核心 2024年第11期251-260,共10页
传统基于熵标准的图像分割法采用穷尽法搜索分割阈值,存在计算代价高、分割效率低的不足。针对这一问题,设计基于Cross熵与改进麻雀搜索算法的图像分割方法。为了提升标准麻雀搜索算法的寻优精度和寻优速率,利用反向学习机制进行种群初... 传统基于熵标准的图像分割法采用穷尽法搜索分割阈值,存在计算代价高、分割效率低的不足。针对这一问题,设计基于Cross熵与改进麻雀搜索算法的图像分割方法。为了提升标准麻雀搜索算法的寻优精度和寻优速率,利用反向学习机制进行种群初始化,改善初始种群结构,提升种群多样性和初始解质量。设计正余弦优化和惯性权重的发现者更新机制,提升发现者全局搜索能力。提出柯西混沌变异的追随者更新机制,结合混沌映射和柯西变异,避免算法产生局部最优。以Cross熵最小为标准评估个体适应度,利用改进麻雀搜索算法寻找图像分割最佳阈值,并实现图像分割。实验结果表明,改进算法在分割指标上表现优异,可以有效提升图像分割精度和分割效率。 展开更多
关键词 图像分割 交叉熵 麻雀搜索算法 反向学习 正余弦算法 柯西变异
下载PDF
基于遗传算法与Hardy-Cross方法的矿井通风机控制
4
作者 杜聿静 马建华 《煤矿机械》 2024年第8期54-57,共4页
针对矿井通风机系统控制的复杂问题,提出了一种遗传算法与Hardy-Cross方法相结合的矿井通风控制,强化了其在处理离散变量和非凸搜索空间中寻找全局最优解的能力。通过数学形式化定义问题并结合基尔霍夫定律,确立了通风机网络的优化模型... 针对矿井通风机系统控制的复杂问题,提出了一种遗传算法与Hardy-Cross方法相结合的矿井通风控制,强化了其在处理离散变量和非凸搜索空间中寻找全局最优解的能力。通过数学形式化定义问题并结合基尔霍夫定律,确立了通风机网络的优化模型。根据实际用风情况智能调节通风机的供风量,以实现能源节约和安全生产的目标。通过对某煤矿的通风案例深入研究和验证,风扇的配置在优化气流方面表现出了卓越性能。该研究不仅为矿山工程领域提供了新的优化思路和方法,也为通风机系统的管理提供了重要参考。 展开更多
关键词 矿井通风 遗传算法 通风机控制 Hardy-cross方法
下载PDF
Machine learning-assisted efficient design of Cu-based shape memory alloy with specific phase transition temperature 被引量:2
5
作者 Mengwei Wu Wei Yong +2 位作者 Cunqin Fu Chunmei Ma Ruiping Liu 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2024年第4期773-785,共13页
The martensitic transformation temperature is the basis for the application of shape memory alloys(SMAs),and the ability to quickly and accurately predict the transformation temperature of SMAs has very important prac... The martensitic transformation temperature is the basis for the application of shape memory alloys(SMAs),and the ability to quickly and accurately predict the transformation temperature of SMAs has very important practical significance.In this work,machine learning(ML)methods were utilized to accelerate the search for shape memory alloys with targeted properties(phase transition temperature).A group of component data was selected to design shape memory alloys using reverse design method from numerous unexplored data.Component modeling and feature modeling were used to predict the phase transition temperature of the shape memory alloys.The experimental results of the shape memory alloys were obtained to verify the effectiveness of the support vector regression(SVR)model.The results show that the machine learning model can obtain target materials more efficiently and pertinently,and realize the accurate and rapid design of shape memory alloys with specific target phase transition temperature.On this basis,the relationship between phase transition temperature and material descriptors is analyzed,and it is proved that the key factors affecting the phase transition temperature of shape memory alloys are based on the strength of the bond energy between atoms.This work provides new ideas for the controllable design and performance optimization of Cu-based shape memory alloys. 展开更多
关键词 machine learning support vector regression shape memory alloys martensitic transformation temperature
下载PDF
Corneal collagen cross-linking in patients with keratoconus from the Dresden protocol to customized solutions:theoretical basis 被引量:1
6
作者 Ciro Caruso Luca D’Andrea +4 位作者 Mario Troisi Michele Rinaldi Raffaele Piscopo Salvatore Troisi Ciro Costagliola 《International Journal of Ophthalmology(English edition)》 SCIE CAS 2024年第5期951-962,共12页
Keratoconus is an ectatic condition characterized by gradual corneal thinning,corneal protrusion,progressive irregular astigmatism,corneal fibrosis,and visual impairment.The therapeutic options regarding improvement o... Keratoconus is an ectatic condition characterized by gradual corneal thinning,corneal protrusion,progressive irregular astigmatism,corneal fibrosis,and visual impairment.The therapeutic options regarding improvement of visual function include glasses or soft contact lenses correction for initial stages,gas-permeable rigid contact lenses,scleral lenses,implantation of intrastromal corneal ring or corneal transplants for most advanced stages.In keratoconus cases showing disease progression corneal collagen crosslinking(CXL)has been proven to be an effective,minimally invasive and safe procedure.CXL consists of a photochemical reaction of corneal collagen by riboflavin stimulation with ultraviolet A radiation,resulting in stromal crosslinks formation.The aim of this review is to carry out an examination of CXL methods based on theoretical basis and mathematical models,from the original Dresden protocol to the most recent developments in the technique,reporting the changes proposed in the last 15y and examining the advantages and disadvantages of the various treatment protocols.Finally,the limits of non-standardized methods and the perspectives offered by a customization of the treatment are highlighted. 展开更多
关键词 corneal collagen cross linking KERATOCONUS custom fast protocol Dresden protocol lambert-beer law Bunsen-roscoe law
下载PDF
Effects of tube cross-sectional shapes on flow pattern, liquid film and heat transfer of n-pentane across tube bundles
7
作者 Xuejing He Zhenlin Li +1 位作者 Ji Wang Hai Yu 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2023年第8期16-25,共10页
The heat transfer of hydrocarbon refrigerant across tube bundles have been widely used in refrigeration.Three-dimensional simulation model using volume of fluid(VOF) was presented to study the effects of tube shapes o... The heat transfer of hydrocarbon refrigerant across tube bundles have been widely used in refrigeration.Three-dimensional simulation model using volume of fluid(VOF) was presented to study the effects of tube shapes on flow pattern, film thickness and heat transfer of n-pentane across tube bundles, including circle, ellipse-shaped, egg-shaped and cam-shaped tube bundles. Simulation results agree well with experimental data in the literature. The liquid film thickness of sheet flow and heat transfer for different tube shapes were obtained numerically. The flow pattern transition occurs lower vapor quality for ellipse-shaped tube than other tube shapes. For sheet flow, the liquid film on circle tube and ellipseshaped tube is symmetrically distributed along the circumferential direction. However, the liquid film on egg-shaped tube at circumferential angles(θ) = 15°–60° is thicker than θ = 135°–165°. The liquid film on cam tube at θ = 15°–60° is slightly thinner than θ = 135°–165°. The liquid film thickness varies from thinner to thicker for ellipse-shaped, cam-shaped, egg-shape and circle within θ = 15°–60°. The effect of tube shape is insignificant on thin liquid film thickness. Ellipse-shaped tube has largest heat transfer coefficient for sheet flow. In practical engineering, the tube shape could be designed as ellipse to promote heat transfer. 展开更多
关键词 Tube shapes Flow pattern Liquid film thickness Heat transfer Two-phase flow
下载PDF
Computer vision-aided DEM study on the compaction characteristics of graded subgrade filler considering realistic coarse particle shapes 被引量:1
8
作者 Taifeng Li Kang Xie +2 位作者 Xiaobin Chen Zhixing Deng Qian Su 《Railway Engineering Science》 EI 2024年第2期194-210,共17页
The compaction quality of subgrade filler strongly affects subgrade settlement.The main objective of this research is to analyze the macro-and micro-mechanical compaction characteristics of subgrade filler based on th... The compaction quality of subgrade filler strongly affects subgrade settlement.The main objective of this research is to analyze the macro-and micro-mechanical compaction characteristics of subgrade filler based on the real shape of coarse particles.First,an improved Viola-Jones algorithm is employed to establish a digitalized 2D particle database for coarse particle shape evaluation and discrete modeling purposes of subgrade filler.Shape indexes of 2D subgrade filler are then computed and statistically analyzed.Finally,numerical simulations are performed to quantitatively investigate the effects of the aspect ratio(AR)and interparticle friction coefficient(μ)on the macro-and micro-mechanical compaction characteristics of subgrade filler based on the discrete element method(DEM).The results show that with the increasing AR,the coarse particles are narrower,leading to the increasing movement of fine particles during compaction,which indicates that it is difficult for slender coarse particles to inhibit the migration of fine particles.Moreover,the average displacement of particles is strongly influenced by the AR,indicating that their occlusion under power relies on particle shapes.The dis-placement and velocity of fine particles are much greater than those of the coarse particles,which shows that compaction is primarily a migration of fine particles.Under the cyclic load,the interparticle friction coefficientμhas little effect on the internal structure of the sample;under the quasi-static loads,however,the increase inμwill lead to a significant increase in the porosity of the sample.This study could not only provide a novel approach to investigate the compaction mechanism but also establish a new theoretical basis for the evaluation of intelligent subgrade compaction. 展开更多
关键词 Subgrade filler particles Deep learning particle shape analysis Particle library Compaction characteristics Discrete element method(DEM)
下载PDF
Cross section determination of^(27)Al(n,2n)^(26)Al reaction induced by 14-MeV neutrons uniting with D-T neutron activation and AMS techniques 被引量:1
9
作者 Xian-Lin Yang Chang-Lin Lan +6 位作者 Yu-Ting Wei Yi Zhang Gong Jiang Bo Xie Yu Liu Hong-Tao Shen Xiao-Jun Sun 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2024年第6期78-89,共12页
Aluminum is the primary structural material in nuclear engineering,and its cross section induced by 14-MeV neutrons is of great significance.To address the issue of insufficient accuracy for the^(27)Al(n,2n)^(26)Al re... Aluminum is the primary structural material in nuclear engineering,and its cross section induced by 14-MeV neutrons is of great significance.To address the issue of insufficient accuracy for the^(27)Al(n,2n)^(26)Al reaction cross section,the activation method and accelerator mass spectrometry(AMS)technique were used to determine the^(27)Al(n,2n)^(26)Al cross section,which could be used as a D-T plasma ion temperature monitor in fusion reactors.At the China Academy of Engineering Physics,neutron activation was performed using a K-400 neutron generator produced by the T(d,n)4He reaction.The^(26)Al∕^(27)Al isotope ratios were measured using the newly installed GYIG 1 MV AMS at the Institute of Geochemistry,Chinese Academy of Sciences.The neutron flux was monitored by measuring the activity of 92mNb produced by the 93Nb(n,2n)92mNb reaction.The measured results were compared with available data in the experimental nuclear reaction database,and the measured values showed a reasonable degree of consistency with partially available literature data.The newly acquired cross-sectional data at 12 neutron energy points through systematic measurements clarified the divergence,which has two different growth trends from the existing experimental values.The obtained results are also compared with the corresponding evaluated database,and the newly calculated excitation functions with TALYS−1.95 and EMPIRE−3.2 codes,the agreement with CENDL−3.2,TENDL-2021 and EMPIRE−3.2 results are generally acceptable.A substantial improvement in the knowledge of the^(27)Al(n,2n)^(26)Al reaction excitation function was obtained in the present work,which will lay the foundation for the diagnosis of the fusion ion temperature,testing of the nuclear physics model,evaluation of nuclear data,etc. 展开更多
关键词 14-MeV neutron ^(27)Al(n 2n)^(26)Al cross section AMS
下载PDF
Correction to:Feasibility study of the photonuclear reaction cross section of medical radioisotopes using a laser Compton scattering gamma source
10
作者 Yu-Ning Gu Wei-Juan Zhao +5 位作者 Xi-Guang Cao Yu-Xuan Yang Ting-Kai Ma Zheng-Li Liao Fei-Long Xu Yu-Gang Ma 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2024年第11期244-244,共1页
Correction to:Nuclear Science and Techniques(2024)35:155 https://doi.org/10.1007/s41365-024-01481-7 In Eq.(2)of this article,the term'i'should be denoted as a subscript,the corrected equation should read N_(0)... Correction to:Nuclear Science and Techniques(2024)35:155 https://doi.org/10.1007/s41365-024-01481-7 In Eq.(2)of this article,the term'i'should be denoted as a subscript,the corrected equation should read N_(0)=σ(E)N_(t)QC_(kbeam)^(e^(-λt_(i)))∫_(0)^(t_(i))e^(λt)dt,(2)The original article has been corrected. 展开更多
关键词 corrected EQUATION cross
下载PDF
Low cross-talk optical addressing of trapped-ion qubits using a novel integrated photonic chip
11
作者 Ana S.Sotirova Bangshan Sun +10 位作者 Jamie D.Leppard Andong Wang Mohan Wang Andres Vazquez-Brennan David P.Nadlinger Simon Moser Alexander Jesacher Chao He Fabian Pokorny Martin J.Booth Christopher J.Ballance 《Light(Science & Applications)》 SCIE EI CSCD 2024年第10期2179-2191,共13页
Individual optical addressing in chains of trapped atomic ions requires the generation of many small,closely spaced beams with low cross-talk.Furthermore,implementing parallel operations necessitates phase,frequency,a... Individual optical addressing in chains of trapped atomic ions requires the generation of many small,closely spaced beams with low cross-talk.Furthermore,implementing parallel operations necessitates phase,frequency,and amplitude control of each individual beam.Here,we present a scalable method for achieving all of these capabilities using a high-performance integrated photonic chip coupled to a network of optical fibre components.The chip design results in very low cross-talk between neighbouring channels even at the micrometre-scale spacing by implementing a very high refractive index contrast between the channel core and cladding.Furthermore,the photonic chip manufacturing procedure is highly flexible,allowing for the creation of devices with an arbitrary number of channels as well as non-uniform channel spacing at the chip output.We present the system used to integrate the chip within our ion trap apparatus and characterise the performance of the full individual addressing setup using a single trapped ion as a light-field sensor.Our measurements showed intensity cross-talk below~10^(-3) across the chip,with minimum observed cross-talk as low as~10^(-5). 展开更多
关键词 SPACING cross OPTICAL
原文传递
基于改进Alpha Shape算法的点云数据岛屿边界提取
12
作者 宋晓辉 熊祖雄 +2 位作者 张炎 吕富强 韦建林 《海洋测绘》 CSCD 北大核心 2024年第1期58-62,共5页
针对机载LiDAR点云的岛屿岸线提取过程复杂、附属岛屿岸线难以提取等问题,提出一种基于改进Alpha Shape算法的点云数据岛屿边界提取方法。首先利用布料模拟滤波算法剔除非岛屿点云数据,通过欧式聚类进行不同岛屿的提取,再将岛屿点云数... 针对机载LiDAR点云的岛屿岸线提取过程复杂、附属岛屿岸线难以提取等问题,提出一种基于改进Alpha Shape算法的点云数据岛屿边界提取方法。首先利用布料模拟滤波算法剔除非岛屿点云数据,通过欧式聚类进行不同岛屿的提取,再将岛屿点云数据投影至二维平面,并根据岛屿点云构建格网。在此基础上使用自适应Alpha Shape算法,对提取出的岛屿点云进行边界提取,即可得到岛屿的岸线轮廓。选取新西兰的玛提尤/萨姆斯岛作为研究区域,并将本文算法与Alpha Shape算法进行对比,结果表明:本文算法提取岛屿边界点云的精准度为97.78%,可以准确地提取岛屿岸线,为海岛规划提供参考。 展开更多
关键词 摄影测量 机载LiDAR点云 边界提取 欧式聚类 自适应Alpha shape
下载PDF
J-shaped association between dietary thiamine intake and the risk of cognitive decline in cognitively healthy,older Chinese individuals
13
作者 Chengzhang Liu Qiguo Meng +7 位作者 Yuanxiu Wei Xinyue Su Yuanyuan Zhang Panpan He Chun Zhou Mengyi Liu Ziliang Ye Xianhui Qin 《General Psychiatry》 CSCD 2024年第1期44-52,共9页
Background The prospective association of dietary thiamine intake with the risk of cognitive decline among the general older adults remains uncertain.Aims To investigate the association between dietary thiamine intake... Background The prospective association of dietary thiamine intake with the risk of cognitive decline among the general older adults remains uncertain.Aims To investigate the association between dietary thiamine intake and cognitive decline in cognitively healthy,older Chinese individuals.Methods The study included a total of 3106 participants capable of completing repeated cognitive function tests.Dietary nutrient intake information was collected through 3-day dietary recalls and using a 3-day food-weighed method to assess cooking oil and condiment consumption.Cognitive decline was defined as the 5-year decline rate in global or composite cognitive scores based on a subset of items from the Telephone Interview for Cognitive Status-modified.Results The median follow-up duration was 5.9 years.There was a J-shaped relationship between dietary thiamine intake and the 5-year decline rate in global and composite cognitive scores,with an inflection point of 0.68 mg/day(95%confidence interval(Cl):0.56 to 0.80)and a minimal risk at 0.60-1.00 mg/day of dietary thiamine intake.Before the inflection point,thiamine intake was not significantly associated with cognitive decline.Beyond the inflection point,each unit increase in thiamine intake(mg/day)was associated with a significant decrease of 4.24(95%Cl:2.22 to 6.27)points in the global score and 0.49(95%Cl:0.23 to 0.76)standard units in the composite score within 5 years.A stronger positive association between thiamine intake and cognitive decline was observed in those with hypertension,obesity and those who were non-smokers(all p<0.05).Conclusions This study revealed a J-shaped association between dietary thiamine intake and cognitive decline in cognitively healthy,older Chinese individuals,with an inflection point at 0.68 mg/day and a minimal risk at 0.60-1.00 mg/day of dietary thiamine intake. 展开更多
关键词 INTAKE shaped cognitive
下载PDF
Synthesis and Charcterization of Silane Crosslinked Hydrogel to pH Sensitive Study
14
作者 Muhammad Awais Shahid Abdul Haseeb Tahir +1 位作者 Zeeshan Ahmad Muhammad Arslan 《American Journal of Analytical Chemistry》 CAS 2024年第5期165-176,共12页
Eco-friendly and biodegradable novel hydrogel were prepared by blending and solution casting method. The designed hydrogel is based on chitosan/ PEG600/Gurgam with carbon nanofiller along silane crosslinked (TEOS) wit... Eco-friendly and biodegradable novel hydrogel were prepared by blending and solution casting method. The designed hydrogel is based on chitosan/ PEG600/Gurgam with carbon nanofiller along silane crosslinked (TEOS) with pH sensitive response to controlled release of drug in biomedical materials and agriculture industry. The various concentration of carbon nanofiller is used to analyze its effect on the fabricated hydrogel characteristics by using FTIR, SEM, TGA, swelling studies (water, buffer and ionic solution). Spectra of FTIR reflected both established and newly developed groups (like hydrogel). COOH group presence is clearly observed in this range in the carbon filler reinforced hydrogel. The SEM micrographs show that CPG0.003 had a collection of polysaccharide chains as thin helices, which is attributed to the increase in the size of porosity. TGA shows to increase concentration of nanofiller enhanced the thermal stability of the designed hydrogels at temperature 25˚C to 550˚C mass loss percentage decrease upto 20% and increase thermal stability. This pH response made these resultant hydrogels as fruitful competitor against the many reported controlled release application. 展开更多
关键词 CHITOSAN Guargum HYDROGEL Carbon Nano Filler Silane cross Linker pH Sensitive
下载PDF
Shape and diffusion instabilities of two non-spherical gas bubbles under ultrasonic conditions
15
作者 包乌日汗 王德鑫 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第1期715-721,共7页
Ultrasonic cavitation involves dynamic oscillation processes induced by small bubbles in a liquid under the influence of ultrasonic waves. This study focuses on the investigation of shape and diffusion instabilities o... Ultrasonic cavitation involves dynamic oscillation processes induced by small bubbles in a liquid under the influence of ultrasonic waves. This study focuses on the investigation of shape and diffusion instabilities of two bubbles formed during cavitation. The derived equations for two non-spherical gas bubbles, based on perturbation theory and the Bernoulli equation, enable the analysis of their shape instability. Numerical simulations, utilizing the modified Keller–Miksis equation,are performed to examine the shape and diffusion instabilities. Three types of shape instabilities, namely, Rayleigh–Taylor,Rebound, and parametric instabilities, are observed. The results highlight the influence of initial radius, distance, and perturbation parameter on the shape and diffusion instabilities, as evidenced by the R_0–P_a phase diagram and the variation pattern of the equilibrium curve. This research contributes to the understanding of multiple bubble instability characteristics, which has important theoretical implications for future research in the field. Specifically, it underscores the significance of initial bubble parameters, driving pressure, and relative gas concentration in determining the shape and diffusive equilibrium instabilities of non-spherical bubbles. 展开更多
关键词 non-spherical bubble shape instability diffusive instability
下载PDF
Asymmetric expression of CA2 and CA13 linked to calcification in the bilateral mandibular condyles cause crossed beaks in chickens
16
作者 Lei Shi Yanyan Sun +14 位作者 Yunlei Li Hao Bai Jingwei Yuan Hui Ma Yuanmei Wang Panlin Wang Aixin Ni Linlin Jiang Pingzhuang Ge Shixiong Bian Yunhe Zong Jinmeng Zhao Adamu MIsa Hailai HTesfay Jilan Chen 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2024年第7期2379-2390,共12页
Crossed beak is a complex mode of inheritance with prevalence ranging from 0.2 to 7.4% in at least 12 chicken strains worldwide.To reveal the intrinsic factors causing crossed beaks,genes expression patterns in bilate... Crossed beak is a complex mode of inheritance with prevalence ranging from 0.2 to 7.4% in at least 12 chicken strains worldwide.To reveal the intrinsic factors causing crossed beaks,genes expression patterns in bilateral mandibular condyle between affected and normal birds were characterized by RNA sequencing analysis in the present studies.Crossed beak was induced by short length of unilateral mandibular ramus,and a total of 110differentially expressed genes were up-or down-regulated in the affected(short)mandibular condyle side as compared to the normal side.Carbonic anhydrase 2(CA2)and Carbonic anhydrase 13(CA13)were enriched in the carbonate dehydratase activity,and high-expressed in mandibular condyle and osteoblasts(P<0.05).However,both were low-expressed in short mandibular condyle side of affected birds(P<0.05).The carbonate dehydratase inhibitor experiments confirmed that there is positive association between the calcification and carbonic anhydrase isoenzymes.Quantitative analysis with cetylpyridinium chloride showed a decrease in calcification when the cells were transfected with an anti-CA13 shRNA.Our research suggested that CA2 and CA13 are down-calcified in shortside mandibular condyle,and caused mandibular ramus to grow slowly.CA2 and CA13 have the critical role in crossed beaks by regulating calcification of mandibular condyle. 展开更多
关键词 CHICKEN crossed beak carbonic anhydrase CALCIFICATION CA2 CA13
下载PDF
Effect of granular shape on radial segregation in a two-dimensional drum
17
作者 徐悦 李然 +3 位作者 迟志鹏 修文正 孙其诚 杨晖 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第4期509-514,共6页
Granular segregation is widely observed in nature and industry.Most research has focused on segregation caused by differences in the size and density of spherical grains.However,due to the fact that grains typically h... Granular segregation is widely observed in nature and industry.Most research has focused on segregation caused by differences in the size and density of spherical grains.However,due to the fact that grains typically have different shapes,the focus is shifting towards shape segregation.In this study,experiments are conducted by mixing cubic and spherical grains.The results indicate that spherical grains gather at the center and cubic grains are distributed around them,and the degree of segregation is low.Through experiments,a structured analysis of local regions is conducted to explain the inability to form stable segregation patterns with obviously different geometric shapes.Further,through simulations,the reasons for the central and peripheral distributions are explained by comparing velocities and the number of collisions of the grains in the flow layer. 展开更多
关键词 granular materials cubic grains shape segregation segregation mechanism
下载PDF
Atomic transport dynamics in crossed optical dipole trap
18
作者 彭鹏 张正熙 +5 位作者 樊耀塬 殷国玲 毛德凯 陈徐宗 熊炜 周小计 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第7期293-301,共9页
We study the dynamical evolution of cold atoms in crossed optical dipole trap theoretically and experimentally. The atomic transport process is accompanied by two competitive kinds of physical mechanics, atomic loadin... We study the dynamical evolution of cold atoms in crossed optical dipole trap theoretically and experimentally. The atomic transport process is accompanied by two competitive kinds of physical mechanics, atomic loading and atomic loss.The loading process normally is negligible in the evaporative cooling experiment on the ground, while it is significant in preparation of ultra-cold atoms in the space station. Normally, the atomic loading process is much weaker than the atomic loss process, and the atomic number in the central region of the trap decreases monotonically, as reported in previous research. However, when the atomic loading process is comparable to the atomic loss process, the atomic number in the central region of the trap will initially increase to a maximum value and then slowly decrease, and we have observed the phenomenon first. The increase of atomic number in the central region of the trap shows the presence of the loading process, and this will be significant especially under microgravity conditions. We build a theoretical model to analyze the competitive relationship, which coincides with the experimental results well. Furthermore, we have also given the predicted evolutionary behaviors under different conditions. This research provides a solid foundation for further understanding of the atomic transport process in traps. The analysis of loading process is of significant importance for preparation of ultra-cold atoms in a crossed optical dipole trap under microgravity conditions. 展开更多
关键词 cold atom crossed optical dipole trap transport process
下载PDF
Tailoring the texture and mechanical properties of 3%Y_(2)O_(3)p/ZGK200 composites fabricated by unidirectional and cross rolling followed by annealing
19
作者 Xihai Li Hong Yan +1 位作者 Zhiwei Shan Rongshi Chen 《Journal of Magnesium and Alloys》 SCIE EI CAS CSCD 2024年第4期1479-1495,共17页
3%Y_(2)O_(3)p/ZGK200 composites were subjected to unidirectional rolling(UR)and cross rolling(CR)at 400℃and 350℃followed by annealing at 300℃for 1 h.The microstructure,texture and mechanical properties of rolled an... 3%Y_(2)O_(3)p/ZGK200 composites were subjected to unidirectional rolling(UR)and cross rolling(CR)at 400℃and 350℃followed by annealing at 300℃for 1 h.The microstructure,texture and mechanical properties of rolled and annealed composites were systematically studied.The rolled composites exhibited a heterogeneous microstructure,consisting of deformed grains elongated along rolling direction(RD)and Y_(2)O_(3)particles bands distributed along RD.After annealing,static recrystallization(SRX)occurred and most deformed grains transformed into equiaxed grains.A non-basal texture with two strong T-texture components was obtained after UR while a non-basal elliptical/circle texture with circle multi-peaks was obtained after CR,indicating that rolling path had great influences on texture of the composites.After annealing process,R-texture component disappeared or weakened,as results,a non-basal texture with double peaks tilting from normal direction(ND)to transverse direction(TD)and a more random non-basal texture with circle multi-peaks were obtained for UR and CR composites,respectively.The yield strength of rolled composites after UR showed obvious anisotropy along RD and TD while a low anisotropic yield strength was obtained after CR.Some Y_(2)O_(3)particles broke during rolling.The fracture of the composites was attributed to the existence of Y_(2)O_(3)clusters and interfacial debonding between particles and matrix during tension,as a result,the ductility was not as superior as matrix alloy. 展开更多
关键词 Magnesium matrix composites Unidirectional rolling cross rolling TEXTURE Mechanical properties
下载PDF
State-selective charge exchange cross sections in collisions of highly-charged sulfur ions with helium and molecular hydrogen
20
作者 朱小龙 崔述成 +9 位作者 邢大地 徐佳伟 B.Najjari 赵冬梅 郭大龙 高永 张瑞田 苏茂根 张少锋 马新文 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第2期29-33,共5页
The state-selective cross section data are useful for understanding and modeling the x-ray emission in celestial observations.In the present work,using the cold target recoil ion momentum spectroscopy,for the first ti... The state-selective cross section data are useful for understanding and modeling the x-ray emission in celestial observations.In the present work,using the cold target recoil ion momentum spectroscopy,for the first time we investigated the state-selective single electron capture processes for S^(q+)–He and H_(2)(q=11–15)collision systems at an impact energy of q×20 keV and obtained the relative state-selective cross sections.The results indicate that only a few principal quantum states of the projectile energy level are populated in a single electron capture process.In particular,the increase of the projectile charge state leads to the population of the states with higher principal quantum numbers.It is also shown that the experimental averaged n-shell populations are reproduced well by the over-barrier model.The database is openly available in Science Data Bank at 10.57760/sciencedb.j00113.00091. 展开更多
关键词 highly charged sulfur ion charge exchange state-selective cross sections COLTRIMS
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部