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Study on tungsten sintering temperature field based on electromagnetic simulation and computational fluid dynamics

Tungsten 2024年第2期6卷 355-366页

作者： Lu-Yan Wang Yue-Guang Yu jian-Xin dong Kai-Ping Du Shan-Yu liu Cao-Bing li University of Science and Technology Beijing Beijing 100083China BGRIMM Technology Group Beijing 100160China China Iron&Steel Research Institute Group Beijing 100081China

In order to study the influence of various sintering variables more intuitively and clearly,electromagnetic field analysis and computational fl uid dynamics are used to analyze the infl uence of gas flow,heating power and other process parameters on the temperature range of medium-frequency sintering in this *** results indicate that the uniformity of temperature fi eld is determined by the gas flow rate and heating *** the heating power is 50 kW,the stable temperature drops about 10 K for every 1 m^(3)·h^(−1)increase of hydrogen *** peak value of the maximum temperature diff erence on the tungsten rods gradually increases with the increase of the hydrogen flow rate,and it appears slightly *** temperature distribution of tungsten rods in furnace is similar with diff erent hydrogen flow *** the same time,the closer to the furnace wall,the higher the temperature of the tungsten *** temperature diff erence between tungsten rods mainly occurred within 1 h after the beginning of *** the heating power can improve the stable temperature,but has little eff ect on the heating *** heating power can increase the peak value of the maximum temperature diff erence on the tungsten rods,but has little eff ect on the occurrence time of the peak value of the maximum temperature diff erence on the tungsten *** the heating power will increase the temperature diff erence of a single tungsten rod,but the temperature diff erence of a single tungsten rod never exceeds 65 *** study can be used to guide the process optimization *** with numerical simulation calculation,the sintering parameters with low energy consumption and high temperature uniformity can be quickly and eff ectively found,thus improving the microstructure and properties of sintered tungsten products.

关键词： Tungsten products Sintering Hydrogen flow rate Heating power

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Synergistic effect of homojunction and Ohmic junctions in CdS boosting spatial charge separation for U(VI)photoreduction

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Nano Research 2024年第8期17卷 6849-6859页

作者： Haonan Pei Zhimin dong Zifan li jian Huang Yuanping jiang Zuojia li lin Xu Xiaohong Cao Yunhai liu Zhibin Zhang Guoping Yang State Key Laboratory of Nuclear Resources and Environment East China University of TechnologyNanchang 330013China

Photo-excited holes usually migrate to the surface of the catalyst and rapidly recombine with electrons,reducing the photocatalytic reduction efficiency of uranium(VI)(U(VI))in radioactive ***,we employed a straightforward synthesis technique to meticulously shape and manipulate the morphology of CdS to precisely construct CdS-Ni dandelion-like composites with different aspect ***,the introduction of crystal facet homojunction with Ohmic contacts in this unique morphology siqnificantly improves the photocatalytic ***-dependent photoluminescence spectroscopy(TD-PL)verifies that the composite material positively effects on the dissociation of *** 30 min,CdS(002)/(102)/Ni-4 removed 98% of the uranium content in solution and showed a rather high apparent rate constant(0.114 min^(−1)),which was 4.8 times higher than that of CdS nanospheres(NSs)(0.024 min^(−1))and 3.7 times higher than that of CdS nanorods(NRs)(0.031 min^(−1)).This is much higher the most reported photocatalysts for U(VI)*** after 5 consecutive cycles,the photocatalytic efficiency only decreased by 7%.This offers a fresh perspective on constructing a new perspective for building a green,efficient,and multi mechanism collaborative catalytic system to remediate environmental pollution.

关键词： uranium dandelion-shaped axial size effect crystal facet homojunction ohmic contact

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Invisible and semi-invisible decays of bottom baryons

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Chinese Physics C 2024年第8期48卷 127-139页

作者： Yong Zheng jian-Nan Ding dong-Hao li Lei-Yi li Cai-Dian Lü Fu-Sheng Yu MOE Frontiers Science Center for Rare Isotopes Lanzhou UniversityLanzhou 730000China School of Nuclear Science and Technology Lanzhou UniversityLanzhou 730000China Center for High Energy Physics Peking UniversityBeijing 100871China Institute of High Energy Physics CASBeijing 100049China School of Physical Sciences University of Chinese Academy of SciencesBeijing 101408China

The similar densities of dark matter and baryons in the universe imply that they may arise from the same ultraviolet model.B-Mesogenesis,which assumes dark matter is charged under the baryon number,attempts to simultaneously explain the origin of baryon asymmetry and dark matter in the *** particular,B-Mesogenesis may induce bottom-baryon decays into invisible or semi-invisible final states,which provide a distinctive signal for probing this *** this work,we systematically study the invisible decays of bottom baryons into dark matter and the semi-invisible decays of bottom baryons into a meson or a photon together with a dark matter *** particular,the fully invisible decay can reveal the stable particles in *** QCD-based frameworks are used to calculate the hadronic matrix elements under the B-Mesogenesis *** estimate the constraints on the Wilson coefficients or the product of some new physics couplings with the Wilson coefficients according to the semi-invisible and invisible decays of bottom baryons detectable at future colliders.

关键词： baryon asymmetry dark matter B-Mesogenesis invisible and semi-invisible decay bottom baryons

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Alignment efficient image-sentence retrieval considering transferable cross-modal representation learning

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Frontiers of Computer Science 2024年第1期18卷 77-91页

作者： Yang YANG Jinyi GUO Guangyu li Lanyu li Wenjie li jian YANG School of Computer Science and Engineering Nanjing University of Science and TechnologyNanjing 210094China Department of Computing Hong Kong Polytechnic UniversityHong Kong 100872China State Key Lab.for Novel Software Technology Nanjing UniversityNanjing 210094China 14th Research Institute of China Electronics Technology Group Corporation Nanjing 210094China guangyu.li2017@***

Traditional image-sentence cross-modal retrieval methods usually aim to learn consistent representations of heterogeneous modalities,thereby to search similar instances in one modality according to the query from another modality in *** basic assumption behind these methods is that parallel multi-modal data(i.e.,different modalities of the same example are aligned)can be obtained in *** other words,the image-sentence cross-modal retrieval task is a supervised task with the alignments as ***,in many real-world applications,it is difficult to realign a large amount of parallel data for new scenarios due to the substantial labor costs,leading the non-parallel multi-modal data and existing methods cannot be used *** the other hand,there actually exists auxiliary parallel multi-modal data with similar semantics,which can assist the non-parallel data to learn the consistent ***,in this paper,we aim at“Alignment Efficient Image-Sentence Retrieval”(AEIR),which recurs to the auxiliary parallel image-sentence data as the source domain data,and takes the non-parallel data as the target domain *** single-modal transfer learning,AEIR learns consistent image-sentence cross-modal representations of target domain by transferring the alignments of existing parallel ***,AEIR learns the image-sentence consistent representations in source domain with parallel data,while transferring the alignment knowledge across domains by jointly optimizing a novel designed cross-domain cross-modal metric learning based constraint with intra-modal domain adversarial ***,we can effectively learn the consistent representations for target domain considering both the structure and semantic ***,extensive experiments on different transfer scenarios validate that AEIR can achieve better retrieval results comparing with the baselines.

关键词： image-sentence retrieval transfer learning semantic transfer structure transfer

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Rapid and chemoselective imidation of sulfides in aqueous buffer enabled by a novel guanidine-derived N-O reagent

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Science China Chemistry 2024年第6期67卷 1929-1934页

作者： Hanzheng li Long Xu Jiajia dong Key Laboratory of Organofluorine Chemistry Center for Excellence in Molecular SynthesisShanghai Institute of Organic ChemistryUniversity of Chinese Academy of SciencesChinese Academy of SciencesShanghai200032China Institute of Translational Medicine National Facility for Translational Medicine(Shanghai)Shanghai Jiao Tong UniversityShanghai200240China School of Chemistry and Chemical Engineering Zhangjiang Institute for Advanced StudyShanghai Jiao Tong UniversityShanghai200240China Shanghai Artificial Intelligence Laboratory Shanghai200232China

Herein we report the facile synthesis of a series of novel N-O reagents and identify N′-di-Boc-N′′-[(mesitylsulfonyl)oxy]-guanidine as an efficient imidating *** reagent is synthetically scalable and bench-stable,yet it shows unprecedented reactivity and chemoselectivity towards S(II)in buffer/hexafluoroisopropanol(HFIP)system,to generate a new class of Nguanyl *** transformation of N-guanyl sulfilimines to N-guanyl sulfoximines provides us a chance to investigate these rarely reached compounds,which are shown to be versatile precursors to a variety of N-heterocyclic and *** work provides an addition to the tool box of both sulfur imidation and guanidine synthesis,especially for the need of rapid and selective modifications of sulfur(II)center under biocompatible conditions.

关键词： sulfur imidation N-O reagent

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Salidroside Ameliorates Lung Injury Induced by PM_(2.5) by Regulating SIRT1-PGC-1αin Mice

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Biomedical and Environmental Sciences 2024年第4期37卷 367-376页

作者： li Xiao Hong liU Yu Mei SHAN Hui TAN Jin Feng ZHOU jian SONG Yuan Jin li Si Qi liU Chen XU dong Qun YU li li Wan Wei School of Public Health Shandong Second Medical UniversityWeifang 261053ShandongChina Key Laboratory of Health Inspection and Quarantine Weifang 261053ShandongChina Weifang Environmental Monitoring Station Weifang 261042ShandongChina Department of Orthopedics The 80th Army Hospital of PLAWeifang 261000ShandongChina Environment and Health Related Product Safety Institute of Chinese Center for Disease Control and Prevention Beijing 100021China School of Basic Medicine Shandong Second Medical UniversityWeifang 261053ShandongChina

Objective This study aimed to clarify the intervention effect of salidroside(SAL)on lung injury caused by PM_(2.5) in mice and illuminate the function of SIRT1-PGC-1ɑ*** Specific pathogen-free(SPF)grade male C57BL/6 mice were randomly assigned to the following groups:control group,SAL group,PM_(2.5) group,SAL+PM_(2.5) *** the first day,SAL was given by gavage,and on the second day,PM_(2.5) suspension was given by intratracheal *** whole experiment consist of a total of 10 cycles,lasting 20 *** the end of treatment,blood samples and lung tissues were collected and *** of pathological changes in lung tissue using inverted microscopy and transmission electron *** expression of inflammatory,antioxidants,apoptosis,and SIRT1-PGC-1ɑproteins were detected by Western *** Exposure to PM_(2.5) leads to obvious morphological and pathologica changes in the lung of ***_(2.5) caused a decline in levels of antioxidant-related enzymes and protein expressions of HO-1,Nrf2,SOD2,SIRT1 and PGC-1ɑ,and an increase in the protein expressions of IL-6,IL-1β,Bax,caspase-9 and cleaved ***,SAL reversed the aforementioned changes caused by PM_(2.5) by activating the SIRT1-PGC-1α *** SAL can activate SIRT1-PGC-1ɑ to ameliorate PM2.5-induced lung injury.

关键词： PM_(2.5) Salidroside Oxidative stress Inflammation Apoptosis SIRT1-PGC-1α

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Neg-Entropy Mechanism as a Target for Natural Medicines

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Engineering 2024年第7期38卷 11-12页

作者： Tian-Le Gao Hui-Hui Guo jian-dong jiang Institute of Materia Medica Chinese Academy of Medical Sciences&Peking Union Medical CollegeBeijing 100050China Institute of Medicinal Biotechnology Chinese Academy of Medical Sciences&Peking Union Medical CollegeBeijing 100050China

Current strategies for drug discovery research mainly focus on molecular targets,in which structure biology plays a central role,such as the detailed mechanism of a drug-target *** principle of this approach is the presumed molecular mechanism or genetic background of the disease being *** this approach has brought progress in understanding the mode of action for some drugs,most prevalent illnesses-especially chronic diseases-are multifactorial and present with a group of symptoms,as is often the case in cardiovascular diseases,metabolic disorders,cancers,and so *** newly emerging term“multi-morbidity”(i.e.,multiple co-occurring diseases)describes a grand challenge for this strategy,and successful drug intervention for multimorbidity should be multifaceted[1].So,our research team has shifted its attention to a new direction that views the disease as a whole instead of a single-molecule abnormality,and focusing on drugs with multiple targets.

关键词： drugs diseases cardiovascular

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Accurate simulations of pure-viscoacoustic wave propagation in tilted transversely isotropic media

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Petroleum Science 2024年第2期21卷 866-884页

作者： Qiang Mao jian-Ping Huang Xin-Ru Mu Ji-dong Yang Yu-jian Zhang Geosciences Department China University of Petroleum(East China)Qingdao266580ShandongChina Pilot National Laboratory for Marine Science and Technology(Qingdao) Qingdao266207ShandongChina

Forward modeling of seismic wave propagation is crucial for the realization of reverse time migration(RTM) and full waveform inversion(FWI) in attenuating transversely isotropic media. To describe the attenuation and anisotropy properties of subsurface media, the pure-viscoacoustic anisotropic wave equations are established for wavefield simulations, because they can provide clear and stable wavefields. However, due to the use of several approximations in deriving the wave equation and the introduction of a fractional Laplacian approximation in solving the derived equation, the wavefields simulated by the previous pure-viscoacoustic tilted transversely isotropic(TTI) wave equations has low accuracy. To accurately simulate wavefields in media with velocity anisotropy and attenuation anisotropy, we first derive a new pure-viscoacoustic TTI wave equation from the exact complex-valued dispersion formula in viscoelastic vertical transversely isotropic(VTI) media. Then, we present the hybrid finite-difference and low-rank decomposition(HFDLRD) method to accurately solve our proposed pure-viscoacoustic TTI wave equation. Theoretical analysis and numerical examples suggest that our pure-viscoacoustic TTI wave equation has higher accuracy than previous pure-viscoacoustic TTI wave equations in describing q P-wave kinematic and attenuation characteristics. Additionally, the numerical experiment in a simple two-layer model shows that the HFDLRD technique outperforms the hybrid finite-difference and pseudo-spectral(HFDPS) method in terms of accuracy of wavefield modeling.

关键词： Pure-viscoacoustic TTI wave equation Attenuation anisotropy Seismic modeling Low-rank decomposition method

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I-DCGAN and TOPSIS-IFP:A simulation generation model for radiographic flaw detection images in light alloy castings and an algorithm for quality evaluation of generated images

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China Foundry 2024年第3期21卷 239-247页

作者： Ming-jun Hou Hao dong Xiao-yuan Ji Wen-bing Zou Xiang-sheng Xia Meng li Ya-jun Yin Bao-hui li Qiang Chen jian-xin Zhou State Key Laboratory of Materials Processing and Die&Mould Technology Huazhong University of Science and TechnologyWuhan 430074China Xinjiang Technology(jiangsu)Co. Ltd.Nantong 226100JiangsuChina Southwest Technique and Engineering Research Institute Chongqing 400039China Shanghai Spaceflight Precision Machinery Institute Shanghai 201600China

The intelligent detection technology driven by X-ray images and deep learning represents the forefront of advanced techniques and development trends in flaw detection and automated evaluation of light alloy ***,the efficacy of deep learning models hinges upon a substantial abundance of flaw *** existing research on X-ray image augmentation for flaw detection suffers from shortcomings such as poor diversity of flaw samples and low reliability of quality *** this end,a novel approach was put forward,which involves the creation of the Interpolation-Deep Convolutional Generative Adversarial Network(I-DCGAN)for flaw detection image generation and a comprehensive evaluation algorithm named TOPSIS-IFP.I-DCGAN enables the generation of high-resolution,diverse simulated images with multiple appearances,achieving an improvement in sample diversity and quality while maintaining a relatively lower computational ***-IFP facilitates multi-dimensional quality evaluation,including aspects such as diversity,authenticity,image distribution difference,and image distortion *** results indicate that the X-ray radiographic images of magnesium and aluminum alloy castings achieve optimal performance when trained up to the 800th and 600th epochs,*** TOPSIS-IFP value reaches 78.7%and 73.8%similarity to the ideal solution,*** to single index evaluation,the TOPSIS-IFP algorithm achieves higher-quality simulated images at the optimal training *** approach successfully mitigates the issue of unreliable quality associated with single index *** image generation and comprehensive quality evaluation method developed in this paper provides a novel approach for image augmentation in flaw recognition,holding significant importance for enhancing the robustness of subsequent flaw recognition networks.

关键词： light alloy casting flaw detection image generator discriminator comprehensive evaluation index

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An unprecedented synthesis of axially chiral biaryls by rearrangement and aromatization of carbocations with central-to-axial conversion of chirality

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Science China Chemistry 2024年第9期67卷 2998-3003页

作者： Qi liu Xue-dong li liang Cheng li liu Beijing National Laboratory for Molecular Sciences(BNLMS) CAS Key Laboratory of Molecular Recognition and FunctionCAS Research/Education Center for Excellence in Molecular SciencesInstitute of ChemistryChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China

The central-to-axial chirality conversion represents a fascinating class of chemical processes consisting of the destruction of stereogenic centers and the simultaneous installation of axial chiral elements,which provides efficient methods for the preparation of axially chiral ***,developing catalytic asymmetric approaches for constructing these central chirality precursors and the efficient central-to-axial chirality conversion remains a challenge due to the requirement of aromatization or elimination *** this work,we have developed an unprecedented enantioselective intramolecular FriedelCrafts alkylation with unactivated-ketone carbonyls from which a chiral tertiary alcohol was generated with high efficiency and excellent *** addition,the central-to-axial chirality conversion strategy has been successfully applied to the synthesis of enantioenriched biaryls via a less-explored carbocation-initiated rearrangement and aromatization under the promotion of Lewis *** methodology provided a straightforward and sustainable access to a broad range of biaryl-2-carboxylic acid and in excellent yields(up to 92%)and excellent central-to-axial chirality conversion(up to 99%conversion percentage).This work could be a great model for developing new methods for synthesizing axially chiral biaryls and a general protocol for the rearrangement and aromatization of carbocations for further functionalization.

关键词： br?nsted acid catalysis desymmetrization phosphoric acid axially chiral biaryls central-to-axial conversion

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