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Understanding the Thermal Impedance of Silicone Rubber/Hexagonal Boron Nitride Composites as Thermal Interface Materials

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Chinese Journal of Polymer Science 2024年第3期42卷 352-363,I0008页

作者： Yuan Ji Shi-da Han Hong Wu Shao-Yun Guo Feng-Shun Zhang Jian-Hui Qiu The State key Laboratory of Polymer Materials Engineering Sichuan Provincial Engineering Laboratory of Plastic/Rubber Complex Processing TechnologyPolymer Research InstituteSichuan UniversityChengdu 610065China Institute of Chemical Materials China Academy of Engineering PhysicsMianyang 621900China Department of Mechanical Engineering Faculty of Systems Science and TechnologyAkita Prefectural UniversityAkita 015-0055Japan

Silicone rubber(SR) composites are most widely used as thermal interface materials(TIMs) for electronics heat dissipation. Thermal impedance as the main bottleneck limiting the performance of TIMs is usually neglected. Herein, the thermal impedance of SR composites loaded with different levels of hexagonal boron nitride(h-BN) as TIMs was elaborated for the first time by the ASTM D 5470 standard test and finite element analysis. It was found that elastic modulus and surface roughness of SR composites increased with the increase of h-BN content, indicating that the conformity was reduced. When the assembly pressure was 0.69 MPa, there existed an optimal h-BN content at which the contact resistance was minimum(0.39 k·cm^(2)·W^(-1)). Although the decreased bond line thickness(BLT) by increasing the assembly pressure was beneficial to reduce the thermal impedance, the proper assembly pressure should be selected to prevent the warpage of the contact surfaces and the increase in contact resistance, according to the compression properties of the SR composites. This study provides valuable insights into fabrication of high-performance TIMs for modern electronic device applications.

关键词： Thermal interface materials Hexagonal boron nitride Thermal impedance Surfaces

High-performance anisotropic SmCo-based magnet with novel microstructure

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Journal of Rare Earths 2024年第8期42卷 1539-1545,I0005页

作者： Yingchang Li Zicao Xing Nengjun Yu Zesong ren Minxiang Pan Qiong Wu Hongliang Ge Minggang Zhu Wei Li College of Materials and Chemistry China jiliang UniversityHangzhou 310018China Division of Functional Materials Research Central Iron and Steel Research InstituteBeijing 100081China

A novel micro structure of magnetically anisotropic Sm Co-based magnet with high-performance is *** magnet consists of SmCo_(7)-H(TbCu_(7)-hexagonal type),Sm_(2)Co_(17)-H(Th_(2)Ni_(17)-hexagonal type)and SmCo_(3)-R(SmCo_(3)-rhombohedral type)*** maximum magnetic energy product of the magnet is 231.69 kj/m^(3),and the intrinsic coercivity is 1005.47 kA/*** outstanding intrinsic coercivity temperature coefficient(β)of-0.125%/k between 298 and 773 k is obtained,which is very close to theβof commercial high-temperature Sm_(2)Co_(17)-based sintered *** initial magnetization curve indicates that the coercivity mechanism is controlled by a domain wall pinning *** SmCo_(3)-R lamellar phase may be a potential pinning center or self-pinning *** microstructure of the magnet is different from that of any previous SmCo-based *** findings provide a new idea for preparing high-performance SmCo-based permanent magnets.

关键词： Rare earths Permanent magnet Composite magnet Melt-spinning Microstructure

New Benthic Fossils from the Late Ediacaran Strata of Southwestern China

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Acta Geologica Sinica(English Edition) 2024年第2期98卷 311-323页

作者： LIU Junping LI Ming TANG Feng ZHAO Jiangtai SONG Sicun ZHOU Ying SONG Xiaohan ren Liudong School of Earth Science and Resources China University of GeosciencesBeijing 10083China Yunnan Institute of Geological Survey Kunming 650216China Chinese Academy of Geological Sciences Beijing 10037China key Laboratory for Stratigraphy and Paleontology MNRCBeijing 10037China School of Earth Science and Engineering Nanjing UniversityNanjing 210093China Department of Earth Sciences University College LondonLondon WC1E 6BTU.K. CAS and Shandong Province key Laboratory of Experimental Marine Biology Center for Ocean Mega-ScienceInstitute of OceanologyChinese Academy of SciencesQingdaoShandong 266071China Institute of Geology Chinese Academy of Geological SciencesBeijing 10037China

The Jiangchuan Biota from the Jiucheng Member(Mb.)of the Dengying Formation(Fm.),discovered in Jiangchuan,eastern Yunnan,China,is marked by copious macrofossils at the apex of the Ediacaran *** fauna features benthic algae with varied holdfasts and other fossils of indeterminate taxonomic affinity and is compositionally unique compared to the Shibantan and Gaojiashan biotas of the Dengying *** the Miaohe and Wenghui biotas of the Doushantuo Fm.,elsewhere in *** novel benthic saccular macroalgal fossil,named here Houjiashania yuxiensis *** ***.,from the Jiangchuan Biota is based on fossils that are sausage-shaped,elongate,tubular,ranging from 0.3 to 4 cm in length,and up to 0.8 cm in *** terminus is blunt and rounded to an obtuse angle,the other is bent with a spread-out surface resembling a holdfast,suggesting a three-dimensional ***,stipe-shaped outgrowths,likely vestiges of sessile saccular life forms,are prevalent in macroalgal fossils of analogous size and shape,as well as present brown algae Scytosiphonaceae,such as Colpomenia and *** new findings augment the diversity of benthic algae,such as those known from the Early Neoproterozoic Longfengshan Biota in North *** benthic algal macrofossils in the Jiucheng *** to knowledge of Late Ediacaran metaphyte diversification and offer more clues about the evolutionary positioning of primitive *** co-occurrence of numerous planktonic and benthic multicellular algae and planktonic microbes might have facilitated ecologically the more extensive later Cambrian explosion evidenced by the Chengjiang Biota in Yunnan.

关键词： paleophytology benthic saccular algae algal evolution Neoproterozoic Jiucheng Member Jiangchuan Biota Yunnan Province

Reorganization of 3D genome architecture provides insights into pathogenesis of early fatty liver disease in laying hens

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Journal of Animal Science and Biotechnology 2024年第3期15卷 1086-1100页

作者： Yanli Liu Zhuqing Zheng Chaohui Wang Yumeng Wang Xi Sun Zhouzheng ren Xin Yang Xiaojun Yang College of Animal Science and Technology Northwest A&F UniversityYangling 712100China Institute of Agricultural Biotechnology Jingchu University of TechnologyJingmen 448000China

Background Fatty liver disease causes huge economic losses in the poultry industry due to its high occurrence and lethality ***-dimensional(3D)chromatin architecture takes part in disease processing by regulating tran-scriptional *** study is carried out to investigate the alterations of hepatic 3D genome and H3k27ac profiling in early fatty liver(FLS)and reveal their effect on hepatic transcriptional reprogramming in laying *** Results show that FLS model is constructed with obvious phenotypes including hepatic visible lipid deposi-tion as well as higher total triglyceride and cholesterol in serum.A/B compartment switching,topologically associat-ing domain(TAD)and chromatin loop changes are identified by high-throughput/resolution chromosome conforma-tion capture(HiC)*** genes of these alternations in hepatic 3D genome organization significantly enrich pathways related to lipid metabolism and hepatic damage.H3k27ac differential peaks and differential expres-sion genes(DEGs)identified through RNA-seq analysis are also enriched in these ***,certain DEGs are found to correspond with changes in 3D chromatin structure and H3k27ac binding in their *** motif analysis reveals that candidate transcription factors are implicated in regulating transcriptional ***,disturbed folate metabolism is observed,as evidenced by lower folate levels and altered enzyme *** Our findings establish a link between transcriptional reprogramming changes and 3D chromatin struc-ture variations during early FLS formation,which provides candidate transcription factors and folate as targets for FLS prevention or treatment.

关键词： 3D chromatin architecture Fatty liver disease Folate H3k27ac profiling Transcription reprogramming

The Modified BAPG_s Method for Support Vector Machine Classifier with Truncated Loss

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Applied Mathematics 2024年第4期15卷 267-278页

作者： kexin ren School of Information Science and Technology Jinan University Guangzhou China

In this paper, we modify the Bregman APGs (BAPGs) method proposed in (Wang, L, et al.) for solving the support vector machine problem with truncated loss (HTPSVM) given in (Zhu, W, et al.), we also add an adaptive parameter selection technique based on (ren, k, et al.). In each iteration, we use the linear approximation method to get the explicit solution of the subproblem and set a function to apply the Bregman distance. Finally, numerical experiments are performed to verify the efficiency of BAPGs.

关键词： HTPSVM Bregman Distance BAPGs Algorithm

Mechanism of Wendan decoction in preventing obesity by regulating multiple signal pathway networks based on gene promoter methylation

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Journal of Traditional Chinese Medical Sciences 2024年第1期11卷 93-100页

作者： Haiyan Yang Meiling ren Ziting Wu Jinchao Li Ping Wang School of Traditional Chinese Medicine Jiangxi University of Chinese MedicineNanchang 330004China Graduate School Jiangxi University of Chinese MedicineNanchang 330004China

Objective:To investigate the potential mechanism of Wendan decoction in obesity by screening target genes with promoter region methylation changes and constructing a multiple signaling pathways network based on promoter ***:The methylation degree of Itgad,Col8a1,Adra2b,Jund,Rab2a,Wnt8b,Fzd9,B4galt7,Pik3cd,Creb1,Stard8,and Mmp1 in the abdominal adipose tissue of obese rats was determined using the Agena MassARRAY *** blot was performed to assess protein expression *** genes were identified based on the methylation degree in the promoter region and protein *** analysis of signaling pathways was conducted to identify relevant target genes and obtain a multiple signaling pathway network associated with *** and terminal effector molecules in the pathway networks were selected as research targets for reverse transcription-polymerase chain reaction(RT-PCR)***:Four genes(Adra2b,Creb1,Itgad,and Pik3cd)showed a degree of promoter methylation consistent with their respective protein expression *** them,Adra2b,Creb1,and Pik3cd expression increased,while that of Itgad *** analysis revealed that Creb1 and Pik3cd were involved in 6 signaling pathways related to obesity:tumor necrosis factor(TNF)signaling pathway,growth hormone synthesis/secretion and action,adenosine 5'-monophosphate-activated protein kinase(AMPk)signaling pathway,relaxin signaling pathway,cyclic nucleotide(cAMP)signaling pathway,and phosphatidylinositol 3-kinase/protein kinase B(PI3k/Akt)signaling ***,a multiple signaling pathways network was constructed based on promoter *** molecules including protein kinase B(AkT),mechanistic target of rapamycin complex 1(mTORC1),and unc-51 like autophagy activating kinase 1(ULk1),as well as terminal effector molecules interleukin-1β(IL-1β),interleukin-6(IL-6),and chemokine(C-X-C motif)ligand 2(CXCL2)were selected as research *** decoct

关键词： Wendan decoction Obesity Signal pathway Methylation

Zero thermal expansion in Cs_(2)W_(3)O_(10)

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Chinese Chemical Letters 2024年第7期35卷 538-541页

作者： Juan Guo Mingyuan Fang Qingsong Liu Xiao ren Yongqiang Qiao Mingju Chao Erjun Liang Qilong Gao School of Physics&Microelectronics Key Laboratory of Materials Physics of Ministry of Education of ChinaZhengzhou UniversityZhengzhou 450052China

Zero thermal expansion materials are important for the practical applications due to their shape stability as changing *** reported concept of average atomic volume is an available method to hunt new zero thermal expansion ***,according to this concept,a tetragonal tungstate Cs_(2)W_(3)O_(10)with zero expansion has been *** is no structure phase transition as increasing temperature from 150 k to 573 *** coefficient of thermal expansion of axes and volume areαa=0.0074×10^(-6)k^(-1),αc=1.63×10^(-6)k^(-1),andαV=1.60×10^(-6)k^(-1),respectively,in the temperature range of 150~573 *** temperature-and pressure-dependent Raman spectra reveal that the vibrations of WO6octahedra libration modes with positive total anharmonicity and W-O-W bending mode with negative Grüneisen parameter are possibly the origin of zero thermal expansion in Cs_(2)W_(3)O_(10).

关键词： Zero thermal expansion Cesium tungstate Raman spectra Average atomic volume Temperature-dependent X-ray diffraction

Reduced magma generation and its implications for the Pulang giant porphyry Cu-polymetallic deposit in Northwest Yunnan,China

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Acta Geochimica 2024年第4期43卷 802-813页

作者： Jingwei Guan Tao ren Lei Wang Shenjin Guan Lianrong Wu Baosheng Shi Faculty of Land Resources Engineering Kunming University of Science and TechnologyKunming 650093People’s Republic of China Diqing Nonferrous Metals Co. LtdShangri-La 674400People’s Republic of China

The Pulang giant porphyry Cu-Mo polymetallic deposit is located in the Zhongdian area in the center of the Sanjiang Tethys tectonic domain,which was formed by the westward subduction of the Garze-Litang oceanic slab beneath the Zhongza ***-pyrrhotite-pyritemolybdenite occurs as disseminations,veins,veinlets,and stockworks distributed in the k-silicate alteration zone in the monzonite porphyry,which is superimposed by *** chemical compositions of biotite and amphibole analyzed by electron probe microanalysis(EPMA)indicate that the ore-forming magma and exsolved fluids experienced a continuous decrease in the oxygen fugacity(fO_(2)).Primary amphibolite and biotite(type I)crystallized at relatively high temperatures(744-827°C)and low fO_(2)(log fO_(2)=−12.26 to−11.91)during the magmatic *** fluids exsolved from the magma have a relatively lower temperature(621-711°C)and fO_(2)(log fO_(2)=−14.36 to−13.32)than the original *** addition,the presence of a high abundance of pyrrhotite and an insufficiency of primary magnetite and sulfate in the ore(i.e.,anhydrite and gypsum)indicate that the deposit may be a reduced porphyry *** and fluid fO_(2)results,combined with previous research on magmatic fO_(2)at the Pulang deposit,indicate that the magma associated with the reduced Pulang ore assemblages was initially generated as a highly oxidized magma that was subsequently reduced by sedimentary rocks of the Tumugou Formation.

关键词： Porphyry deposit Oxygen fugacity(fO_(2)) Contamination of surrounding rock Pulang Zhongdian arc

Discovering the ultralow thermal conductive A_(2)B_(2)O_(7)-type high-entropy oxides through the hybrid knowle dge-assiste d data-driven machine learning

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Journal of Materials Science & Technology 2024年第1期168卷 131-142页

作者： Ying Zhang ke ren William Yi Wang Xingyu Gao Ruihao Yuan Jun Wang Yiguang Wang Haifeng Song Xiubing Liang Jinshan Li State key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi’an 710072China Innovation Center NPU ChongqingChongqing 401135China Institute of Advanced Structure Technology Beijing Institute of TechnologyHaidian DistrictBeijing 100081China Laboratory of Computational Physics Institute of Applied Physics and Computational MathematicsBeijing 100088China Defense Innovation Institute Academy of Military Sciences of the PLA of ChinaBeijing 100071China

Lattice engineering and distortion have been considered one kind of effective strategies for discovering advanced *** instinct chemical flexibility of high-entropy oxides(HEOs)motivates/accelerates to tailor the target properties through phase transformations and lattice ***,a hybrid knowledge-assisted data-driven machine learning(ML)strategy is utilized to discover the A_(2)B_(2)O_(7)-type HEOs with low thermal conductivity(κ)through 17 rare-earth(RE=Sc,Y,La-Lu)solutes optimized A-site.A designing routine integrating the ML and high throughput first principles has been proposed to predict the key physical parameter(kPPs)correlated to the targetedκof advanced *** the smart-designed 6188(5RE_(0.2))_(2)Zr_(2)O_(7)HEOs,the best candidates are addressed and validated by the princi-ples of severe lattice distortion and local phase transformation,which effectively reduceκby the strong multi-phonon scattering and weak interatomic ***,(Sc_(0.2)Y_(0.2)La_(0.2)Ce_(0.2)Pr_(0.2))_(2)Zr_(2)O_(7)with predictedκbelow 1.59 Wm^(−1)k^(−1)is selected to be verified,which matches well with the ex-perimentalκ=1.69 Wm^(−1)k^(−1)at 300 k and could be further decreased to 0.14 Wm^(−1)k^(−1)at 1473 ***,the coupling effects of lattice vibrations and charges on heat transfer are revealed by the cross-validations of various models,indicating that the weak bonds with low electronegativity and few bond-ing charge density and the lattice distortion(r∗)identified by cation radius ratio(r A/r B)should be the kPPs to decreaseκ*** work supports an intelligent designing strategy with limited atomic and electronic kPPs to accelerate the development of advanced multi-component HEOs with proper-ties/performance at multi-scales.

关键词： High-entropy oxides Thermal conductivity Pyrochlore key physical parameter First-Principles