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Comparative Experimental Study on Heat Transfer Characteristics of Building Exterior Surface at High and Low Altitudes

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Journal of Thermal Science 2024年第3期33卷 1119-1131页

作者： JIA Yonghong GUO Shurui LI Jin GUO Lei CHENG Zhu zhang yin YANG Hanyu LONG Enshen Institute for Disaster Management and Reconstruction Sichuan UniversityChengdu610065China MOE Key Laboratory of Deep Earth Science and Engineering College of Architecture and EnvironmentSichuan UniversityChengdu610065China

The external surface heat transfer coefficient of building envelope is one of the important parameters necessary for building energy saving design,but the basic data in high-altitude area are scarce.Therefore,the authors propose a modified measurement method based on the heat balance of a model building,and use the same model building to measure its external surface heat transfer coefficient under outdoor conditions in Chengdu city,China at an altitude of 520 m and Daocheng city at an altitude of 3750 m respectively.The results show that the total heat transfer coefficient(h_(t))of building surface in high-altitude area is reduced by 34.48%.The influence of outdoor wind speed on the convective heat transfer coefficient(h_(c))in high-altitude area is not as significant as that in low-altitude area.The fitting relation between convection heat transfer coefficient and outdoor wind speed is also obtained.Under the same heating power,the average temperature rise of indoor and outdoor air at highaltitude is 41.9%higher than that at low altitude,and the average temperature rise of inner wall is 25.8%higher than that at low altitude.It shows that high-altitude area can create a more comfortable indoor thermal environment than low-altitude area under the same energy consumption condition.It is not appropriate to use the heat transfer characteristics of the exterior surface of buildings in low-altitude area for building energy saving design and related heating equipment selection and system terminal matching design in high-altitude area.

关键词： altitude heat transfer characteristics convective heat transfer coefficient(h_(c)) radiative heat transfer coefficient(h_(r)) external building envelope

Research on the Legal Framework of Content Regulations for Network Platforms

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Contemporary Social Sciences 2024年第1期9卷 137-155页

作者： zhang yin Liao Xinyue Southwest University of Political Science and Law

In the era of the Internet,various network platforms have evolved into new hubs for information dissemination.Currently,China has established a platform-centered content regulation framework,wherein platforms proactively enforce content regulations in accordance with legal censorship obligations.Additionally,platform policies and user agreements augment their authority in content regulation.The platforms can achieve cost-effective and highly efficient content regulation by leveraging their strategic advantages enabled by their own technical capabilities and extensive coverage.The platform self-regulation model,however,still faces challenges.First,accurately evaluating content remains a formidable task;second,ensuring effective platform publicity through self-regulation poses difficulties;third,users may potentially face disadvantages due to the platform’s right of self-regulation;and fourth,digital copyright owners face challenges when defending digital copyright disputes under the safe harbor rule.Therefore,it is imperative to establish,review,and revise the legal framework for content regulation of network platforms in order to enhance the efficiency of their governance systems.The formulation of the legal framework for content regulation of network platforms may encompass the following aspects:rationalizing obligations pertaining to platform content regulations,enhancing supervision over platform self-regulation,and establishing a dual-track responsibility system for digital copyright content regulation.This will ensure a harmonious balance among public interests,users’personal rights and interests,and commercial benefits through regulating the content on network platforms.

关键词： content regulations platform self-regulation legal framework

Efficiently simulating the work distribution of multiple identical bosons with boson sampling

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Frontiers of physics 2024年第3期19卷 197-206页

作者： Wen-Qiang Liu zhang-qi yin Center for Quantum Technology Research and Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurements(MOE) School of PhysicsBeijing Institute of TechnologyBeijing 100081China

Boson sampling has been theoretically proposed and experimentally demonstrated to show quantum computational advantages.However,it still lacks the deep understanding of the practical applications of boson sampling.Here we propose that boson sampling can be used to efficiently simulate the work distribution of multiple identical bosons.We link the work distribution to boson sampling and numerically calculate the transition amplitude matrix between the single-boson eigenstates in a one-dimensional quantum piston system,and then map the matrix to a linear optical network of boson sampling.The work distribution can be efficiently simulated by the output probabilities of boson sampling using the method of the grouped probability estimation.The scheme requires at most a polynomial number of the samples and the optical elements.Our work opens up a new path towards the calculation of complex quantum work distribution using only photons and linear optics.

关键词： quantum simulation quantum work distribution boson sampling linear optic

Umami taste components in chicken-spices blends and potential effect of aroma on umami taste intensity

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Food Science and Human Wellness 2024年第3期13卷 1220-1230页

作者： Rani Andaleeb Yiwen Zhu Ninglong zhang Danni zhang Muzahir Hussain yin zhang yingshuang Lu Yuan Liu Department of Food Science&Technology School of Agriculture&BiologyShanghai Jiao Tong UniversityShanghai 200240China Tianjin Key Laboratory of Food Science and Health School of MedicineNankai UniversityTianjin 300071China MoBioFood Research Group Department of Biochemistry and BiotechnologyUniversitat Rovirai VirgiliTarragona 43007Spain Animal Nutrition Institut de Recercai Tecnologia Agroalimentàries(IRTA)Centre Mas BovéConstantí43120Spain Key Laboratory of Meat Processing of Sichuan Chengdu UniversityChengdu 610106China

In this study,umami taste intensity(UTI)and umami taste components in chicken breast(CB)and chickenspices blends were characterized using sensory and instrumental analysis.Our main objective was to assess the aroma-umami taste interactions in different food matrices and reconcile the aroma-taste perception to assist future product development.The impact of key aroma,including vegetable-note"2-pentylfuran",meaty"methional",green"hexanal",and spicy-note-estragole and caryophyllene"on UTI was evaluated in monosodium glutamate and chicken extract.We found that spices significantly decreased UTI and umami taste components in CB.Interestingly,the perceptually similar odorants and tastants exhibited the potential to enhance UTI in food matrices.Methional was able to increase the UTI,whereas spicy and green-note components could reduce the UTI significantly.This information would be valuable to food engineers and formulators in aroma selection to control the UTI perceived by consumers,thus,improving the quality and acceptability of the chicken products.

关键词： Chicken-spices blends Umami taste components Aroma-taste interactions Perceptual similarity Umami taste intensity

Attaining synergetic equilibrium of electrical conductivity and tensile strength in GQDs@GN/Cu composites through multi-scale intragranular and intergranular reinforcements

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Rare Metals 2024年第1期43卷 366-379页

作者： Shuang-yin zhang Liang Liu Rui Bao Jian-Hong Yi Sheng-Da Guo Faculty of Materials Science and Engineering Kunming University of Science and TechnologyKunming 650093China Key Laboratory of Advanced Materials of Yunnan Province Kunming University of Science and TechnologyKunming 650093China Faculty of Materials Metallurgy and Chemistry Jiangxi University of Science and TechnologyGanzhou 341000China

The configuration and quality of reinforcements, as well as the robustness of interfacial bonding,holding a critical significance in determining the concurrence between electrical conductivity and mechanical strength in metal matrix composites. In this study, citric acid was employed as the precursor for synthesizing multiscale carbon nanomaterials(graphene quantum dots and graphene, abbreviated as GQDs and GN). The GQDs@GN/Cu composites were fabricated through a segmented ball milling process in conjunction with subsequent spark plasma sintering(SPS). The intragranular GQDs and intergranular GQDs@GN had synergistically reinforced Cu composites through Orowan strengthening, load transfer strengthening and refinement strengthening. Furthermore,the robust interface bonding between GQDs@GN and Cu effectively mitigated interfacial impedance stemming from electron-boundary scattering. The yield strength and ultimate tensile strength of the GQDs@GN/Cu composites were recorded as 270 and 314 MPa, respectively, representing an improvement of 92 and 28% over pure Cu, while maintaining electrical conductivity at a level comparable to that of pure Cu. This study advances the understanding of the possibility of realizing a synergistic compatibility between electrical conductivity and mechanical strength in Cu composites.

关键词： Cu matrix composites Interface bonding Mechanical property Graphene quantum dots(GQDs) Electrical conductivity

Metal-Organic Frameworks Housing Active Molecules as Bioinspired Catalysts

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CCS Chemistry 2024年第6期6卷 1380-1402页

作者： yin zhang Peter E.VanNatta Junyu Ren Shengqian Ma Department of Chemistry University of North TexasDentonTexas 76201 Department of Chemical and Biomolecular Engineering National University of SingaporeSingapore 117585

Optimization of activity,selectivity,and stability of catalysts for practical application is a long-soughtafter goal.Recent progress in the advancement of rational catalyst design routinely takes queues from nature.Specifically,enzymes are renowned for their high efficiency and selectivity in diverse and significant reactions under mild conditions.Despite the well-known merits of enzymes,they often remain unsuitable for industrial catalysis due to issues,including limited environment(solvent/temperature/pH)compatibility,considerable structural uncertainty,and highly specific reaction scopes.In the context of bioinspired catalysis design,the development of synthetic heterogeneous catalyst analogs,which may not only mimic enzymes to reproduce or even surpass their performance but also bypass their intrinsic limitations,is thus,desirable and has been extensively studied in the context of porous materials.The metal-organic framework(MOF)is a superior candidate for porous materials towards this goal,thanks to facile and modular preparation,explicit crystalline composition/structure,tunable pore size/environment,and excellent stability.The introduction of active molecular species such as bioactive molecules(e.g.,proteins,enzymes,peptides,amino acids,porphyrins)and chemically active molecules(e.g.,frustrated Lewis pairs)into metal-organic frameworks(MOFs)via pore encapsulation,chemical postmodification,or bottom-up construction has been shown to facilitate the cooperative enhancement of catalysis through the enforcement of proximity,enhancement of control/activity,and even inducement of unexpected selectivity.In this minireview,we sought to summarize the last 5 years of fruitful progress,exploiting MOFs housing active molecules for substantial catalysis applications,including asymmetric reactions,CO_(2)conversion(reduction,cycloaddition),biocatalytic H_(2)O_(2)/dye degradation,and so on,and discuss challenges and opportunities in the prospective exploration of these systems towards enzyme mimicry and new-to-nature catal

关键词： metal-organic framework bioinspired catalyst active molecular species

Laser-induced Synthesis of Ultrafine Gold Nanoparticles in Covalent Organic Frameworks

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Chemical Research in Chinese Universities 2022年第2期38卷 468-471页

作者： zhang yin MA Shengqian Department of Chemistry University of North TexasDentonTX 76201USA

Metal nanoparticles in porous supports are of great importance for catalysis, separation and sensing, but their controllable preparation is still largely unmet. Herein, we describe a simple laser-induced synthesis of ultrafine gold nanoparticles in the covalent organic framework. Gold nanoparticles are well embedded, and they are about (1±0.1) nm in size. This work is universal for the preparation of well-dispersed and ultrafine metal nanoparticles in porous supports.

关键词： Metal nanoparticle Covalent organic framework(COF) Ultrafine Photoreduction

Four New Terpyridine Complexes Based Polyoxometalates with[W_(10)O_(32)]^(4-) Anions as High-Efficiency Dual-Site Catalysis for Thioether Oxidation Reaction

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Chinese Journal of Chemistry 2024年第6期42卷 592-598页

作者： yin zhang Wei-Dong Yu Fang-Qian Wang Xiangnan Wang Jiawan Zhou Chao Liu Jun Yan Junior Education Department Changsha Normal UniversityChangshaHunan410100 China School of Science Hunan University of Technology and BusinessChangshaHunan410000 China College of Chemistry and Chemical Engineering Central South UniversityChangshaHunan410000 China

Polyoxometalates modified with complex cations have attracted increasing attention because of the fascinating properties and the controllable structures.By adjusting the synthesis conditions,four new terpyridine complexes based hybrid POMs,[(TPY-H)CuCl]_(4)[W_(10)O_(32)]·2DMF·2H_(2)O(1),[(TPY-H)Cu(DMSO)(H_(2)O)]_(2)[W_(10)O_(32)]·2H_(2)O(2),[(TPY-H)_(2)Cu]_(2)[W_(10)O_(32)]·6DMSO·8H_(2)O(3) and[(TPY-Br)CuCl(DMSO)(H_(2)O)]_(2)[(TPY-Br)CuCl]_(2)[W_(10)O_(32)]·2DMSO·4H_(2)O(4),were prepared by using‘one-pot’method.Sing-crystal X-ray diffraction analyses,infrared radiation,etc.,revealed the structural composition of compounds 1—4,which indicates that synthesis conditions have a directional regulatory effect on the compounds synthesis.Thioether oxidation catalytic reactions show 1—4 have good catalytic activities,and powder X-ray diffraction and thermogravimetry analysis show 1—4 have superduper catalytic stability.Moreover,4 has better catalytic activity because of the different structure of terpyridine complexes.Therefore,a possible mechanism of dual-site catalysis by both cations and anions is proposed.

关键词： Polyoxometalates Terpyridine complexes Thioether oxidation Dual-site catalysis Clusters

Monitoring and analysis of snow cover change in an alpine mountainous area in the Tianshan Mountains,China

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Journal of Arid Land 2022年第9期14卷 962-977页

作者： zhang yin GULIMIRE Hanati SULITAN Danierhan HU Keke State Key Laboratory of Desert and Oasis Ecology Xinjiang Institute of Ecology and GeographyChinese Academy of SciencesUrumqi 830011China Aksu National Station of Observation and Research for Oasis Agro-ecosystem Aksu 843017China University of Chinese Academy of Sciences Beijing 100049China Xinjiang Institute of Water Resources and Hydropower Research Urumqi 830049China

Estimating the snow cover change in alpine mountainous areas(in which meteorological stations are typically lacking)is crucial for managing local water resources and constitutes the first step in evaluating the contribution of snowmelt to runoff and the water cycle.In this paper,taking the Jingou River Basin on the northern slope of the Tianshan Mountains,China as an example,we combined a new moderate-resolution imaging spectroradiometer(MODIS)snow cover extent product over China spanning from 2000 to 2020 with digital elevation model(DEM)data to study the change in snow cover and the hydrological response of runoff to snow cover change in the Jingou River Basin under the background of climate change through trend analysis,sensitivity analysis and other methods.The results indicate that from 2000 to 2020,the annual average temperature and annual precipitation in the study area increased and snow cover fraction(SCF)showed obvious signs of periodicity.Furthermore,there were significant regional differences in the spatial distribution of snow cover days(SCDs),which were numerous in the south of the basin and sparse in the central of the basin.Factors affecting the change in snow cover mainly included temperature,precipitation,elevation,slope and aspect.Compared to precipitation,temperature had a greater impact on SCF.The annual variation in SCF was limited above the elevation of 4200 m,but it fluctuated greatly below the elevation of 4200 m.These results can be used to establish prediction models of snowmelt and runoff for alpine mountainous areas with limited hydrological data,which can provide a scientific basis for the management and protection of water resources in alpine mountainous areas.

关键词： snow cover fraction snow cover days snowmelt runoff sensitivity analysis climate change Jingou River Basin Tianshan Mountains