检索结果-南通市图书馆

Brillouin Klein space and half-turn space in three-dimensional acoustic crystals

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science Bulletin 2024年第13期69卷 2050-2058页

作者： Zhenxiao Zhu Linyun yang Jien Wu Yan Meng Xiang Xi Bei Yan Jingming Chen Jiuyang Lu Xueqin Huang Weiyin Deng Ce Shang Perry Ping Shum yihao yang Hongsheng Chen Kexin Xiang Gui-Geng Liu Zhengyou Liu Zhen Gao State Key Laboratory of Optical Fiber and Cable Manufacture Technology Department of Electronic and Electrical EngineeringSouthern University of Science and TechnologyShenzhen 518055China School of Physics and Optoelectronics South China University of TechnologyGuangzhou 510640China Key Laboratory of Artificial Micro-and Nanostructures of Ministry of Education and School of Physics and Technology Wuhan UniversityWuhan 430072China King Abdullah University of Science and Technology(KAUST) Physical Science and Engineering Division(PSE)Thuwal 23955-6900Saudi Arabia Interdisciplinary Center for Quantum Information State Key Laboratory of Modern Optical InstrumentationZJU-Hangzhou Global Science and Technology Innovation CenterCollege of Information Science and Electronic EngineeringZJU-UIUC InstituteZhejiang UniversityHangzhou 310027China Division of Physics and Applied Physics School of Physical and Mathematical SciencesNanyang Technological UniversitySingapore 637371Singapore Institute for Advanced Studies Wuhan UniversityWuhan 430072China

The Bloch band theory and Brillouin zone(BZ)that characterize wave-like behaviors in periodic mediums are two cornerstones of contemporary physics,ranging from condensed matter to topological *** theoretical breakthrough revealed that,under the projective symmetry algebra enforced by artificial gauge fields,the usual two-dimensional(2D)BZ(orientable Brillouin two-torus)can be fundamentally modified to a non-orientable Brillouin Klein bottle with radically distinct manifold ***,the physical consequence of artificial gauge fields on the more general three-dimensional(3D)BZ(orientable Brillouin three-torus)was so far ***,we theoretically discovered and experimentally observed that the fundamental domain and topology of the usual 3D BZ can be reduced to a non-orientable Brillouin Klein space or an orientable Brillouin half-turn space in a 3D acoustic crystal with artificial gauge *** experimentally identify peculiar 3D momentum-space non-symmorphic screw rotation and glide reflection symmetries in the measured band ***,we experimentally demonstrate a novel stacked weak Klein bottle insulator featuring a nonzero Z2 topological invariant and self-collimated topological surface states at two opposite surfaces related by a nonlocal twist,radically distinct from all previous 3D topological *** discovery not only fundamentally modifies the fundamental domain and topology of 3D BZ,but also opens the door towards a wealth of previously overlooked momentum-space multidimensional manifold topologies and novel gaugesymmetry-enriched topological physics and robust acoustic wave manipulations beyond the existing paradigms.

关键词： Momentum-space non-symmorphic symmetry Brillouin Klein space and half-turn space Acoustic Klein bottle insulator Self-collimated topological surface states

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

天然裂缝对水力压裂煤的起裂及扩展试验研究

煤炭科学技术 2024年第5期52卷 92-101页

作者：蒋长宝杨毅毫刘辉辉郭建泉付银兰吴家耀重庆大学煤矿灾害动力学与控制全国重点实验室重庆400030 兖矿能源集团股份有限公司济宁三号煤矿山东济宁272169 自然资源部复杂构造区非常规天然气评价与开发重点实验室贵州贵阳550009

水力压裂是提高低渗透高瓦斯煤层抽采效率和瓦斯产量的有效方法之一。由于煤层中存在丰富的天然裂缝,天然裂缝与水力裂缝相互作用会使水力裂缝的起裂和扩展形式呈现出复杂多样性,从而影响煤层的增透效果。为研究水力压裂煤在天然裂缝作... 详细信息

水力压裂是提高低渗透高瓦斯煤层抽采效率和瓦斯产量的有效方法之一。由于煤层中存在丰富的天然裂缝,天然裂缝与水力裂缝相互作用会使水力裂缝的起裂和扩展形式呈现出复杂多样性,从而影响煤层的增透效果。为研究水力压裂煤在天然裂缝作用下的起裂和扩展规律,利用自主研发的多功能真三轴流固耦合试验系统开展了煤的水力压裂试验。基于“孔壁应力集中诱发拉伸破裂”理论研究了水力压裂煤的裂缝起裂规律,并结合断裂力学从细观角度揭示了水力压裂煤的裂缝扩展机制。研究结果表明:天然裂缝的存在会诱导水力裂缝沿着天然裂缝方向扩展,极大降低了煤岩的起裂压力。不含明显天然裂缝煤岩压裂所需的起裂压力与根据拉伸破坏起裂准则计算的理论起裂压力结果相近,符合“孔壁应力集中诱发拉伸破裂”准则;含明显天然裂缝煤岩压裂所需的起裂压力均小于根据拉伸破坏起裂准则计算的理论起裂压力,且当天然裂缝方向垂直于最小主应力方向时,所需的起裂压力较小,为3.355 MPa;当天然裂缝平行于最小主应力时,所需的起裂压力仅大于最小主应力,为7.902 MPa。水力裂缝类型为I型时,不含明显天然裂缝煤岩的实测最小和最大扩展压力值均大于理论计算最小和最大扩展压力值,差值范围分别为2.043~6.845 MPa和3.951~8.576 MPa;当煤岩含明显天然裂缝且天然裂缝方向平行于X方向时,水平应力差的存在将引起煤岩的实测扩展压力值小于理论计算的扩展压力值。水力裂缝类型为Ⅱ型或I-Ⅱ型时,随着水力裂缝长度的增加,裂缝扩展所需压力逐渐减小。

关键词：天然裂缝地应力水力压裂裂缝扩展纳米压痕

短视频个性化推荐与使用意愿的倒U形关系研究

在线全文

学校读者我要写书评

暂无评论

现代情报 2024年第3期44卷 81-92页

作者：田晓旭毕新华杨一毫李彩宁吉林大学商学与管理学院吉林长春130012

[目的/意义]个性化推荐在促进信息系统使用方面具有积极作用,但过度的个性化推荐也会造成用户的隐私忧虑以致降低使用意愿。短视频情境下,个性化推荐与使用意愿之间的具体关系目前还不清楚。[方法/过程]基于隐私计算理论,探索短视频个... 详细信息

[目的/意义]个性化推荐在促进信息系统使用方面具有积极作用,但过度的个性化推荐也会造成用户的隐私忧虑以致降低使用意愿。短视频情境下,个性化推荐与使用意愿之间的具体关系目前还不清楚。[方法/过程]基于隐私计算理论,探索短视频个性化推荐与用户使用意愿之间的非线性关系。划分短视频类型并选取实用型短视频、享乐型短视频和隐私关注作为调节变量。运用层次回归分析的方法,应用Stata软件对假设进行验证。[结果/结论]个性化推荐与短视频使用意愿之间存在倒U形关系;隐私关注对倒U形关系存在显著的调节作用;不同类型短视频对倒U形关系的影响存在差异,且仅有实用型短视频的调节作用得到验证。

关键词：短视频个性化推荐使用意愿倒U形隐私计算理论短视频类型隐私关注

槲皮素对高脂饮食诱导肥胖小鼠肝脏脂肪变性的改善作用及对色氨酸代谢物的影响

在线全文

学校读者我要写书评

暂无评论

现代食品科技 2024年第6期40卷 96-103页

作者：郭晴君杨惠蘩杨蕴妍李淑欢杨宜浩谢佳玉苏立杰广州医科大学公共卫生学院广东广州511436

探讨槲皮素干预通对高脂饮食诱导肥胖小鼠肝脏脂肪变性的改善作用及对色氨酸代谢物的影响。该实验采用高脂饮食建立肥胖小鼠模型。将雄性C57BL/6J小鼠随机分为对照组(NC)、模型组(HFD)和槲皮素干预组(HFD+Q),每组10只。HFD+Q组小鼠灌胃... 详细信息

探讨槲皮素干预通对高脂饮食诱导肥胖小鼠肝脏脂肪变性的改善作用及对色氨酸代谢物的影响。该实验采用高脂饮食建立肥胖小鼠模型。将雄性C57BL/6J小鼠随机分为对照组(NC)、模型组(HFD)和槲皮素干预组(HFD+Q),每组10只。HFD+Q组小鼠灌胃给予槲皮素(50 mg/***),持续16周。称量小鼠体质量和肝脏组织的质量;组织切片和油红O染色检测肝脏脂肪沉积情况,ELISA检测丙氨酸氨基转移酶(ALT)、天门冬氨酸氨基转移酶(AST)、总胆固醇(TC)、三酰甘油(TG)水平;qPCR检测炎症因子白介素-1β(IL-1β)、肿瘤坏死因子-α(TNF-α)、白介素-6(IL-6)以及脂质代谢相关基因脂肪酸合成酶(FAS)、固醇调节元件结合蛋白1c(SREBP-1c)和ATP结合盒转运体A1(ABCA1)等基因的相对表达量;LC-MS技术靶向分析血清中色氨酸代谢产物吲哚-3-乙酸(IAA)和吲哚-3-丙酸(IPA)的含量。槲皮素干预能显著减少肥胖小鼠的体质量增加(P<0.05),减少肝脏脂肪沉积,降低炎症因子TNF-α(62.96%)、IL-1β(42.52%)和IL-6(50.88%)mRNA表达水平,抑制FAS(80.36%)、SREBP-1c(23.54%),提高ABCA1(5.21倍)脂质代谢基因mRNA表达;增加色氨酸代谢物IAA(1.71倍)和IPA(1.12倍)的含量。结论提示,槲皮素可减少肝脏脂肪沉积,减少肝脏炎性因子的表达,改善高脂饮食诱导的肥胖小鼠肝脏脂肪变性,同时增加血清中吲哚-3-乙酸、吲哚-3-丙酸等色氨酸代谢物含量。

关键词：槲皮素肝脏脂肪变性色氨酸代谢物肠道菌群

High-performance bifunctional polarization switch chiral metamaterials by inverse design method

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

npj Computational Materials 2019年第1期5卷 324-331页

作者： Chuanbao Liu yang Bai Ji Zhou Qian Zhao yihao yang Hongsheng Chen Lijie Qiao Beijing Advanced Innovation Center for Materials Genome Engineering University of Science and Technology BeijingBeijing 100083China Key Laboratory of Environmental Fracture(Ministry of Education) Institute for Advanced Materials and TechnologyUniversity of Science and Technology BeijingBeijing 100083China State Key Laboratory of New Ceramics and Fine Processing Tsinghua UniversityBeijing 100084China State Kay Laboratory of Tribology Department of Mechanical EngineeringTsinghua UniversityBeijing 100084China State Key Laboratory for Modern Optical Instrumentation Zhejiang UniversityHangzhou 310027China

Multifunctional polarization controlling plays an important role in modern photonics,but their designs toward broad bandwidths and high efficiencies are still rather ***,by applying the inverse design method of model-based theoretical paradigm,we design cascaded chiral metamaterials for different polarization controls in oppositely propagating directions and demonstrate their broadband and high-efficiency performance theoretically and *** with the derivation of scattering matrix towards specified polarization control,a chiral metamaterial is designed as a meta-quarter-wave plate for the forward propagating linearly polarized wave,which converts the x-or y-polarized wave into a nearly perfect left-or right-handed circularly polarized wave;intriguingly,it also serves as a 45°polarization rotator for the backward propagating linearly polarized *** bifunctional metamaterial shows a high transmission as well as a broad bandwidth due to the Fabry–Perot-like interference *** the similar approach,an abnormal broadband meta-quarter-wave plate is achieved to convert the forward x-and y-polarized or the backward y-and x-polarized waves into left-and right-handed circularly polarized waves with high transmission *** integration of multiple functions in a single structure endows the cascaded chiral metamaterials with great interests for the high-efficiency polarization-controlled applications.

关键词： chiral polarized inverse

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

某皮卡车动力总成悬置性能优化

汽车实用技术 2024年第17期49卷 103-108页

作者：黎绍涛杨年炯任磊杨艺豪孟浩伟广西科技大学机械与汽车工程学院广西柳州545006 中国汽车工程研究院股份有限公司重庆401122

动力总成悬置系统是影响车内振动响应的关键因素,是噪声、振动和声振粗糙度(NVH)性能优化中的重要一环。针对某皮卡车主观评价时方向盘怠速振动过大问题进行研究,通过测试发现,因动力总成悬置隔振能力不足,导致动力总成激励无法有效衰减... 详细信息

动力总成悬置系统是影响车内振动响应的关键因素,是噪声、振动和声振粗糙度(NVH)性能优化中的重要一环。针对某皮卡车主观评价时方向盘怠速振动过大问题进行研究,通过测试发现,因动力总成悬置隔振能力不足,导致动力总成激励无法有效衰减,引发方向盘振动过大。针对该问题,对样车动力总成悬置系统进行开发,以解耦率为优化目标,基于非支配排序遗传算法(NSGA-II)和能量解耦法,使用iSIGHT与MATLAB进行联合分析,对发动机悬置隔振性能进行优化,结合实车进行优化验证,优化后悬置系统隔振量基本达到20dB,方向盘振动主观评价可接受,该研究方法对样车NVH开发有一定指导意义。

关键词：怠速振动悬置隔振能量解耦遗传算法

维普期刊数据库博看期刊

Targeted mutagenesis of amino acid transporter genes for rice quality improvement using the CRISPR/Cas9 system

在线全文

学校读者我要写书评

暂无评论

The Crop Journal 2020年第3期8卷 457-464页

作者： Shiyu Wang yihao yang Min Guo Chongyuan Zhong Changjie Yan Shengyuan Sun Jiangsu Key Laboratory of Crop Genetics and Physiology/Key Laboratory of Plant Functional Genomics of the Ministry of Education/Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding Yangzhou 225009JiangsuChina Jiangsu Co-Innovation Center for Modern Production Technology of Grain Crops Yangzhou 225009JiangsuChina Agricultural College of yangzhou University Yangzhou 225009JiangsuChina

High grain protein content(GPC) reduces rice eating and cooking quality(ECQ). We generated OsAAP6 and OsAAP10 knockout mutants in three high-yielding japonica varieties and one japonica line using the CRISPR/Cas9 system. Mutation efficiency varied with genetic background in the T_0 generation, and GPC in the T_1 generation decreased significantly,owing mainly to a reduction in glutelin content. Amylose content was down-regulated significantly in some Osaap6 and all Osaap10 mutants. The increased taste value of these mutants was supported by Rapid Visco Analysis(RVA) profiles, which showed higher peak viscosity and breakdown viscosity and lower setback viscosity than the wild type. There were no significant deficiencies in agronomic traits of the mutants. Targeted mutagenesis of OsAAP6 and OsAAP10, especially OsAAP10, using the CRISPR/Cas9 system can rapidly reduce GPC and improve ECQ of rice, providing a new strategy for the breeding cultivars with desired ECQ.

关键词： AAP RVA Targeted mutagenesis of amino acid transporter genes for rice quality improvement using the CRISPR/Cas9 system CRISPR

Photonic amorphous topological insulator

在线全文

学校读者我要写书评

暂无评论

Light(Science & Applications) 2020年第1期9卷 726-733页

作者： Peiheng Zhou Gui-Geng Liu Xin Ren yihao yang Haoran Xue Lei Bi Longjiang Deng Yidong Chong Baile Zhang National Engineering Research Center of Electromagnetic Radiation Control Materials University of Electronic Science and Technology of China610054 ChengduChina Division of Physics and Applied Physics School of Physical and Mathematical SciencesNanyang Technological University21 Nanyang LinkSingapore 637371Singapore Centre for Disruptive Photonic Technologies The Photonics InstituteNanyang Technological University50 Nanyang AvenueSingapore 639798Singapore

The current understanding of topological insulators and their classical wave analogs,such as photonic topological insulators,is mainly based on topological band ***,standard band theory does not apply to amorphous phases of matter,which are formed by non-crystalline lattices with no long-range positional order but only shortrange order,exhibiting unique phenomena such as the glass-to-liquid ***,we experimentally investigate amorphous variants of a Chern number-based photonic topological *** tuning the disorder strength in the lattice,we demonstrate that photonic topological edge states can persist into the amorphous regime prior to the glass-to-liquid *** the transition to a liquid-like lattice configuration,the signatures of topological edge states *** interplay between topology and short-range order in amorphous lattices paves the way for new classes of non-crystalline topological photonic bandgap materials.

关键词： transition amorphous insulator

基于三维点云计算的CO_(2)-水-岩反应程度量化表征方法

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

实验技术与管理 2024年第6期41卷 9-19页

作者：蒋长宝程岳李春梅侯典东杨毅毫焦冰洋赵冬邓博知重庆大学煤矿灾害动力学与控制全国重点实验室重庆400030 重庆大学材料科学与工程学院重庆400030 兖矿能源集团股份有限公司济宁三号煤矿山东济宁272169

CO_(2)地质封存是减少大气中CO_(2)排放,降低温室效应的重要途径,CO_(2)注入含水地层中时,CO_(2)-水-岩反应可能引起岩石矿物的侵蚀,对CO_(2)地质封存安全性产生显著影响。在室内实验中,通过表征岩石表面的形貌特征可以有效地评估CO_(2)... 详细信息

CO_(2)地质封存是减少大气中CO_(2)排放,降低温室效应的重要途径,CO_(2)注入含水地层中时,CO_(2)-水-岩反应可能引起岩石矿物的侵蚀,对CO_(2)地质封存安全性产生显著影响。在室内实验中,通过表征岩石表面的形貌特征可以有效地评估CO_(2)-水-岩反应程度,为CO_(2)地质封存的安全性评估提供科学依据。通过三维点云计算可以精确量化地表征CO_(2)-水-岩反应程度,这种方法首先运用三维激光扫描技术,构建岩石表面的三维模型,确定CO_(2)-水处理前岩石表面三维模型的基准面,并基于处理前的均方根粗糙度确定处理后岩石表面三维模型的基准面。基于三维模型点云信息,提出了两种不同的体积计算新方法,并通过对规则模型体积的计算比较了两种计算方法的准确性与适用性,可根据实际情况选择两种计算方法量化表征CO_(2)-水处理前后岩石表面的侵蚀体积。最后,以陕西省咸阳市某煤矿煤样为例,开展了CO_(2)-水-岩反应模拟试验,验证了计算的可行性。试验结果表明:该文提出的侵蚀体积计算方法可有效地量化表征CO_(2)-水-岩反应程度,CO_(2)-水处理后岩石表面不同区域的侵蚀差异性明显,岩石表面的侵蚀体积与均方根粗糙度之间存在显著的正比关系,随着均方根粗糙度的增大,侵蚀体积也相应上升。

关键词：三维点云 CO_(2)-水-岩基准面均方根粗糙度反应程度