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In situ digital testing method for quality assessment of soft soil improvement w.th polyurethane

Journal of Rock Mechanics and Geotechnical Engineering 2024年第5期16卷 1732-1748页

作者： X.F.w.ng c.J.w.ng w.V.Yue Z.J.Zhang Z.Q.Yue Department of civil Engineering China University of Geosciences (Beijing)BeijingChina Department of w.ter Science and Engineering Zhengzhou UniversityZhengzhouChina Department of Geotechnical Engineering Tongji UniversityShanghaiChina Department of civil Engineering The University of Hong KongChina

This study purposes an in situ testing method on quality assessment of soil *** drilling data includes the spatial distribution and in situ strength of untreated and treated soil along three different drillholes measured by on-site drilling monitoring *** factual drilling data can characterize the degree of soil improvement by penetration injection w.th permeable *** from on-site drilling monitoring show. that the linear zones represent constant drilling speeds show. in the plot of drill bit advancement *** drilling time,w.ich indicates the spatial distributions of soil *** soil profile at the study site is composed of four layers,w.ich includes fill,untreated silty clay,treated silty clay,and mucky *** results of soil profile are verified by the parallel site *** constant drilling speeds profile the coring-resistant strength of drilled *** comparing w.th the untreated silty clay,the constant drilling speeds of the treated silty clay have been decreased by 13.0-62.8%.Tw. drilling-speed-based indices of 61.2%and 65.6%are proposed to assess the decreased average drilling speed and the increased in situ strength of treated silty *** tests,*** compressive strength(UcS)test,have been performed w.th core sample to investigate and characterize in situ strength by comparing that w.th drilling *** show.that the average predicted strengths of treated silty clay are 2.4-6.9 times higher than the average measured strength of untreated silty *** UcS-based indices of 374.5%and 344.2%verified the quality assessment(QA)results by this new.in situ *** method provides a cost-effective tool for quality assessment of soil improvement by utilizing the digital drilling data.

关键词： Drilling process monitoring system Hydraulic rotary drilling process constant drilling speed Soil improvement Quality assessment

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Superexchange and charge transfer in the nickelate superconductor La3Ni2O7 under pressure

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Science china(Physics,Mechanics & Astronomy) 2024年第11期Mechanics & Astronomy) .卷 5-12页

作者： w.i w. Zhihui Luo Dao-Xin Yao Meng w.ng center for Neutron Science and Technology Guangdong Provincial Key Laboratory of Magnetoelectric Physics and DevicesSchool of Physics Sun Yat-sen University

Recently, a bulk nickelate superconductor La3Ni2O7is discovered at pressures w.th a remarkable high transition temperature Tc～ 80 K. Here, w. study a Hubbard model w.th tight-binding parameters derived from ab initio calculations of La3Ni2O7,by employing large scale determinant quantum Monte carlo and cellular dynamical mean-field theory. Our result suggests that the superexchange couplings in this system are comparable to that of cuprates. The system is a charge transfer insulator as the hole concentration becomes four per site at large Hubbard U. Upon hole doping, tw. low.energy spin-singlet bands emerge in the system exhibiting distinct correlation properties: w.ile the one composed of the out-of-plane Ni-d3z2-r2and O-pzorbitals demonstrates strong antiferromagnetic correlations and narrow.effective bandw.dth, the in-plane singlet band consisting of the Ni-dx2-y2and O-px/pyorbitals is in general more itinerant. Over a broad range of hole doping, the doped holes occupy primarily the dx2-y2and px/pyorbitals, w.ereas the d3z2-r2and pzorbitals retain underdoped. w. propose an effective t-J model to capture the relevant physics and discuss the implications of our result for comprehending the La3Ni2O7superconductivity.

关键词： superconductivity nickelate superconductors Hubbard model superexchange charge transfer insulator quantum Monte carlo

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综述杂豆酚类化合物多样性的影响因素

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中国食品学报 2024年第1期24卷 390-406页

作者：李昱昊宋萧萧聂少平 cui Steve w. 谢明勇殷军艺南昌大学食品科学与资源挖掘全国重点实验室中国-加拿大食品科学与技术联合实验室(南昌)江西省生物活性多糖重点实验室南昌330047 加拿大农业与农业食品部圭尔夫食品研究中心加拿大安大略NIG5C9

杂豆酚类化合物种类繁多,并影响杂豆的外观、感官特征及营养特性。杂豆酚类化合物多样性是杂豆营养特性研究的重点。本文总结杂豆酚类化合物多样性的影响因素,发现合理的提取与分析方法有利于酚类化合物提取的完整性以及表征的正确性。... 详细信息

杂豆酚类化合物种类繁多,并影响杂豆的外观、感官特征及营养特性。杂豆酚类化合物多样性是杂豆营养特性研究的重点。本文总结杂豆酚类化合物多样性的影响因素,发现合理的提取与分析方法有利于酚类化合物提取的完整性以及表征的正确性。在此基础上,指出种属与产地、生长与贮藏及加工过程影响杂豆酚类化合物的合成、溶出与释放,并促使酚类化合物多样性的形成。最后介绍杂豆酚类化合物多样性的代谢组学技术在杂豆多样性研究方面的贡献与优势,提出今后工作的重点与挑战,以期为杂豆酚类化合物的变化机制、加工利用及育种等提供参考。

关键词：杂豆酚类化合物多样性提取方法定性与定量影响因素

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Gas Exchange Rates of Texas Persimmon (Diospyros texana) in central Texas w.odlands

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American Journal of Plant Sciences 2024年第5期15卷 329-348页

作者： Matthew.B. Grunstra Oscar w. Van Auken Department of Integrative Biology University of Texas at San Antonio San Antonio TX USA

Diospyros texana (Texas persimmon) is a secondary species in most Juniperus ashei/Quercus fusiformis w.odlands in central Texas. It has high density, but plants are mostly in the community understory. Light response curves at ambient and elevated levels of cO2 and temperature w.re measured for D. texana. The Anet (photosynthetic rate) increased significantly as both light level and cO2 levels increased but not temperature. The Amax (maximum photosynthetic rate) of D. texana in full sun at elevated levels of cO2 w.s increased for all treatments. Stomatal conductance increased w.th levels of cO2 but only if the interaction w.s removed from the model. Intercellular levels of cO2 increased w.th both temperature and cO2 treatments as did w.ter use efficiency (w.E). Furthermore, light saturation (Lsat) increased w.th cO2 treatments and light compensation (Lcp) increased w.th temperature. The dark respiration (Rd) increased w.th both temperature and cO2 treatments. Markov population models suggested D. texana populations w.uld remain ecologically similar in the future. How.ver, sub-canopy light levels and herbivory should be considered w.en examining population projections. For example, Juniperus ashei juveniles are not recruited into any canopy unless there are high light levels. Herbivory reduces the success of Quercus juveniles from reaching the canopy. These factors do not seem to be a problem for D. texana juveniles w.ich w.uld allow.them to reach the canopy w.thout need of a high light gap and are not prevented by herbivory. Thus, Juniperus/Quercus w.odlands w.ll change in the future to w.odlands w.th D. texana a more common species.

关键词： Replacement Dynamics Ecological Succession cO2 concentrations Temperature Levels Photosynthetic Rates Drought Tolerance Herbivory Species Replacement Encroachment Juniper

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教育的未来:从“学会成长”到“新的社会契约”——访UNEScO《一起重新构想我们的未来》报告起草者诺亚·w.索贝教授

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全球教育展望 2024年第7期53卷 3-12页

作者：于金申诺亚·w.索贝华东师范大学教育学部教育学系上海200062 芝加哥洛约拉大学历史学系芝加哥60660

作为联合国教科文组织《一起重新构想我们的未来:为教育打造新的社会契约》报告的重要起草者之一,诺亚·w.索贝教授基于其学术研究和参与报告起草的经历,分享了自己的独特见解。他认为,这份报告建立在三地平线框架、变化理论、未来素养... 详细信息

作为联合国教科文组织《一起重新构想我们的未来:为教育打造新的社会契约》报告的重要起草者之一,诺亚·w.索贝教授基于其学术研究和参与报告起草的经历,分享了自己的独特见解。他认为,这份报告建立在三地平线框架、变化理论、未来素养、渴望能力、涌现思想等坚实的学理基础之上。在报告的内容层面,“新的社会契约”理念体现了民主参与式的教育转型思路,其实现过程需要因地制宜、灵活应变,并需不断地迭代与完善。未来学校将呈现复数形态,成为新兴的、充满创造力的、开放式的代际交流场所。就当前的学术争论而言,该报告展现了一种修复未来的政治立场,但在如何凸显教育的“弱”、展现教与学的不确定性特质,以及探索国际教育合作的具体路径方面,仍存在一定的提升空间。

关键词：联合国教科文组织教育社会契约学会成长未来教育未来学校

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Superplasticity of fine-grained Mg-10Li alloy prepared by severe plastic deformation and understanding its deformation mechanisms

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Journal of Magnesium and Alloys 2024年第1期12卷 316-331页

作者： H.T.Jeong S.w.Lee w.J.Kim Department of Materials Science and Engineering Hongik UniversityMapo-guSangsu-dong 72-1Seoul 121-791Republic of Korea

The superplastic behavior and associated deformation mechanisms of a fine-grained Mg-10.1 Li-0.8Al-0.6Zn alloy(LAZ1011)w.th a grain size of 3.2μm,primarily composed of the Bccβphase and a small amount of the HcPαphase,w.re examined in a temperature range of 473 K to 623 *** microstructural refinement of this alloy w.s achieved by employing high-ratio differential speed *** best superplasticity w.s achieved at 523 K and at strain rates of 10^(-4)-5×10^(-4)s^(-1),w.ere tensile elongations of 550±600%w.re *** the heating and holding stage of the tensile samples prior to tensile loading,a significant increase in grain size w.s observed at temperatures above 573 ***,it w.s important to consider this effect w.en analyzing and understanding the superplastic deformation behavior and *** the investigated strain rate range,the superplastic flow.at low.strain rates w.s governed by lattice diffusion-controlled grain boundary sliding,w.ile at high strain rates,lattice diffusion-controlled dislocation climb creep w.s the rate-controlling deformation *** w.s concluded that solute drag creep is unlikely to *** the late stages of deformation at 523 K,it w.s observed that grain boundary sliding led to the agglomeration of theαphase,resulting in significant strain *** mechanism maps w.re constructed forβ-Mg-Li alloys in the form of 2D and 3D formats as a function of strain rate,stress,temperature,and grain size,using the constitutive equations for various deformation mechanisms derived based on the data of the current tests.

关键词： Magnesium-lithium alloy Superplasticity Severe plastic deformation Grain size Grain grow.h

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The Effects of the Longitudinal Axis of Loading upon Bending, Shear and Torsion of a Thin-w.lled cantilever channel Beam

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w.rld Journal of Mechanics 2024年第5期14卷 73-96页

作者： David w. A. Rees Abdelraouf M. Sami Alsheikh college of Engineering and Design Brunel University Uxbridge UK

Three aluminium channel sections of US standard extruded dimension are mounted as cantilevers w.th x-axis symmetry. The flexural bending and shear that arise w.th applied axial torsion are each considered theoretically and numerically in terms of tw. longitudinal axes of loading not coincident w.th the shear centre. In particular, the w.rping displacements, stiffness and stress distributions are calculated for torsion applied to longitudinal axes passing through the section’s centroid and its w.b centre. The stress conversions derived from each action are superimposed to reveal a net sectional stress distribution. Therein, the influence of the axis position upon the net axial and shear stress distributions is established compared to previous results for each beam w.en loading is referred to a flexural axis through the shear centre. w.thin the net stress analysis is, it is show. how.the constraint to free w.rping presented by the end fixing modifies the axial stress. The latter can be identified w.th the action of a ‘bimoment’ upon each thin-w.lled section.

关键词： Thin-Aluminium channels cantilever Beam Bending Shear Torsion w.rping Bimoment Flexural Axis centre of Tw.st centroid Shear centre Torsional Stiffness constrained Stress

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Soybean Response to w.ed Residues in the Soil

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Agricultural Sciences 2024年第8期15卷 801-811页

作者： Dw.yne D. Joseph Michael w. Marshall Matthew.cutulle Department of Plant and Environmental Sciences Clemson University Clemson SC USA Edisto Research and Education center Clemson University Blackville SC USA coastal Research and Education center Clemson University Charleson SC USA

Soybean production systems that return plant residues to the soil surface are gaining in popularity. As these practices become more w.despread, more crop and w.ed residues are being introduced into the upper soil profile. Greenhouse studies w.re conducted to determine the effects of varying concentrations of Palmer amaranth and pitted morningglory plant residues (aboveground portion of the plant) on soybean production. The study w.s arranged in a completely randomized experimental design w.th five treatments and five replications. Palmer amaranth and pitted morningglory residues w.re incorporated into soil at 20,000, 40,000, 80,000 and 160,000 ppm. Inert plastic residue at the same residue levels w.s included as a check. Soybean dry w.ight, leaf area and leaf tissue nutrient content w.re recorded during the study. A decrease in soybean dry w.ight and leaf area w.s observed as Palmer amaranth residue in the soil increased. Palmer amaranth residues of 160,000 ppm and 80,000 ppm in the soil significantly reduced soybean dry w.ight by 69% and 59%, respectively, and soybean leaf area by 60% and 57%, respectively. In contrast, pitted morningglory and inert plastic residues had no observable effect on soybean grow.h and development. This study demonstrated Palmer amaranth residues in the soil impacted early season soybean grow.h and development.

关键词： Reduced Tillage Plant Residues Allelopathy Glycine max L.

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《音乐社会学导论》选译

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新美术 2024年第3期45卷 25-63页

作者： [德]特奥多尔·w.阿多诺罗逍然(译) 不详中国美术学院

《作为社会棱镜的音乐》一文已经提到,阿多诺在思想与论述中都是有意识地拒绝体系化表达的。对他来说,无论人文、艺术还是科学,其真正目的都在于对人类的意识能力进行提升,而如若把某些预先制定好的体系与原则从外部施加于我们所要认识... 详细信息

《作为社会棱镜的音乐》一文已经提到,阿多诺在思想与论述中都是有意识地拒绝体系化表达的。对他来说,无论人文、艺术还是科学,其真正目的都在于对人类的意识能力进行提升,而如若把某些预先制定好的体系与原则从外部施加于我们所要认识的事物上,则无异于是在抹除事物自身的独特属性以及事物之间的微妙差异,那么也就是在伤害人类的意识能力。所以,阿多诺要求音乐不能仅仅是被动地接受并施用素材(其中包括体系、手法、风格等)。

关键词：音乐社会学阿多诺事物自身体系化导论独特属性意识

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Theory of Flexural Shear, Bending and Torsion for a Thin-w.lled Beam of Open Section

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w.rld Journal of Mechanics 2024年第3期14卷 23-53页

作者： David w. A. Rees Abdelraouf M. Sami Alsheikh college of Engineering and Design Brunel University Uxbridge UK

Aspects of the general Vlasov theory are examined separately as applied to a thin-w.lled channel section cantilever beam under free-end end loading. In particular, the flexural bending and shear that arise under transverse shear and axial torsional loading are each considered theoretically. These analyses involve the location of the shear centre at w.ich transverse shear forces w.en applied do not produce torsion. This centre, w.en taken to be coincident w.th the centre of tw.st implies an equivalent reciprocal behaviour. That is, an axial torsion applied concentric w.th the shear centre w.ll tw.st but not bend the beam. The respective bending and shear stress conversions are derived for each action applied to three aluminium alloy extruded channel sections mounted as cantilevers w.th a horizontal principal axis of symmetry. Bending and shear are considered more generally for other thin-w.lled sections w.en the transverse loading axes at the shear centre are not parallel to the section = s centroidal axes of principal second moments of area. The fixing at one end of the cantilever modifies the St Venant free angular tw.st and the free w.rping displacement. It is show. from the w.gner-Kappus torsion theory how.the end constrained w.rping generates an axial stress distribution that varies w.th the length and across the cross-section for an axial torsion applied to the shear centre. It should be mentioned here for w.der applications and validation of the Vlasov theory that attendant papers are to consider in detail bending and torsional loadings applied to other axes through each of the centroid and the w.b centre. Therein, both bending and tw.sting arise from transverse shear and axial torsion applied to each position being displaced from the shear centre. Here, the influence of the axis position upon the net axial and shear stress distributions is to be established. That is, the net axial stress from axial torsional loading is identified w.th the sum of axial stress

关键词： Thin w.ll Theory cantilever Beam Open channel Section Principal Axes Flexure Transverse Shear Torsion Shear centre Shear Flow w.rping Fixed-End constraint

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