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Bubble-templated Construction of Three-dimensional Ceramic Network for Enhanced Thermal Conductivity of Silicone Rubber Composites

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Chinese Journal of Polymer Science 2021年第7期39卷 789-795页

作者： Shou-Jun Li Jing-Chao Li Pei-ZhiJi Wen-Feng Zhang yong-lai lu Li-Qun Zhang State Key Laboratory of Organic-Inorganic Composites Beijing University of Chemical TechnologyBeijing 100029China Beijing Key Laboratory of Wood Science and Engineering&MOE Key Laboratory of Wooden Material Science and Application Beijing Forestry UniversityBeijing W0083China Key Laboratory of Carbon Fiber and Functional Polymers Ministry of EducationBeijing University of Chemical TechnologyBeijing 100029China Engineering Research Center of Elastomer Materials Energy Conservation and Resources Ministry of EducationBeijing University of Chemical TechnologyBeijing 100029China

With the continuous development of the electronics industry,the energy density of modern electronic devices increases constantly,thus releasing a lot of heat during *** electronic devices take higher and higher request to the thermal interface *** high thermal conductivity needs to establish an interconnecting thermal conductivity network in the *** this purpose,the suspension of Al203 and curdlan was first foamed to construct a bubble-templated continuous ceramic *** to the rapid gelation property of curdlan,we can easily remove moisture by hot air ***,the high thermally conductive composites are prepared by vacuum impregnation of silicone *** result showed that composites prepared by our method have higher thermal conductivity than the samples obtained by traditional *** thermal conductivity of the prepared composite material reached 1.253 W·m^(-1)·K·^-(1)when the alumina content was 69.6 wt%.This facile method is expected to be applied to the preparation of high-performance thermal interface materials.

关键词： Thermally conductive network Alumina Curdlan Thermal conductivity

Dispersion and Filler Network Structure of Fibrillar Silicates in Elastomers

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Chinese Journal of Polymer Science 2016年第7期34卷 858-872页

作者： Zhao Li Hai-bin Sun Cong-yi Li yong-lai lu Wang Qiao 宁南英 Li-qun Zhang 田明 Aeolus Tyre Co. Ltd State Key Laboratory of Organic-Inorganic Composites Beijing University of Chemical Technology Petro China Sichuan Petrochemical Co. Ltd Office of Scientific Research and Development Beijing University of Chemical Technology

The dispersion and filler network of fibrillar silicate（FS） in elastomers were studied. The results showed that a good dispersion of FS in matrix during mechanical blending in unvulcanized composites contributed to a strong FS filler network, different from that of traditional reinforcing fillers. Meanwhile, the filler re-aggregation during vulcanization caused by the overlapping and intertwining of FS further strengthened the filler network. The factors including Mooney viscosity and molecular polarity of elastomer, type and amount of silane coupling agents used for filler modification, that may influence the filler network, were studied. Our study helps us to understand the mechanism for the formation of filler network of FS in elastomers and provides guidance for the preparation of high performance FS/elastomer composites.

关键词： Fibrillar silicates Dispersion Filler network Elastomers

Research on the influences of motion characteristics of jetting projectile charge under water

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Defence Technology（防务技术） 2024年第3期33卷 411-425页

作者： Xing Chen yong-gang lu Institute of Systems Engineering China Academy of Engineering PhysicsMianyang 621900SichuanChina

Shaped charge warhead is important for enhancing the damage performance of underwater *** paper used finite element analysis software and based on JPC water penetration experiments to examine the influence of liner parameters(wall thickness,material),charge aspect ratio,and stand-off distance on the movement characteristics of JPC in *** findings reveal that the head diameter of the JPC increases and experiences significant erosion after entering the water,the effective length of the JPC in water undergoes two distinct phases:a growth phase and a decrease phase,with the velocity of the JPC decaying *** the liner thickness,stand-off distance and the charge aspect ratio can improve the erosion resistance and the velocity retention capacity of the *** optimal ranges for liner thickness and stand-off distance are 0.0363D_(k) to 0.0545D_(k)(D_(k) is the charge diameter),the stand-off distance should be within 1.0D_(k).After the charge aspect ratio higher than 1.25,the charge structure exerts minimal influence the movement characteristics of the JPC in *** density plays a crucial role in the velocity decay pattern of the JPC during *** with higher densities exhibit superior velocity retention capabilities in water,with the velocity decay pattern converging if the densities are ***,copper,tantalum and tungsten liners are deemed appropriate for underwater shaped charge ***,the results will provide an important reference for the design of underwater shaped charge warhead.

关键词： JPC Movement characteristics Underwater penetration Numerical simulation

p-d Orbital Hybridization Engineered Single-Atom Catalyst for Electrocatalytic Ammonia Synthesis

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Energy & Environmental Materials 2024年第2期7卷 119-125页

作者： Jingkun Yu Xue yong Siyu lu Green Catalysis Center and College of ChemistryZhengzhou UniversityZhengzhou 450001China Department of Chemistry University of SheffieldSheffieldS37HFUK

The rational design of metal single-atom catalysts(SACs)for electrochemical nitrogen reduction reaction(NRR)is ***-dimensional metal-organic frameworks(2DMOFs)is a unique class of promising *** to now,the roles of individual metals,coordination atoms,and their synergy effect on the electroanalytic performance remain ***,in this work,a series of 2DMOFs with different metals and coordinating atoms are systematically investigated as electrocatalysts for ammonia synthesis using density functional theory *** a specific metal,a proper metal-intermediate atoms p-d orbital hybridization interaction strength is found to be a key indicator for their NRR catalytic *** hybridization interaction strength can be quantitatively described with the p-/d-band center energy difference(Δd-p),which is found to be a sufficient descriptor for both the p-d hybridization strength and the NRR *** maximum free energy change(ΔG_(max))andΔd-p have a volcanic relationship with OsC_(4)(Se)_(4)located at the apex of the volcanic curve,showing the best NRR *** asymmetrical coordination environment could regulate the band structure subtly in terms of band overlap and *** work may shed new light on the application of orbital engineering in electrocatalytic NRR activity and especially promotes the rational design for SACs.

关键词： first-principle calculations Nitrogen reduction p-d orbital hybridization single-atom catalysts

High mechanical strength Si anode synthesis with interlayer bonded expanded graphite structure for lithium-ion batteries

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Journal of Energy Chemistry 2024年第6期93卷 253-263,I0007页

作者： Wenhui lai Jong Hak Lee lu Shi Yuqing Liu Yanhui Pu yong Kang Ong Carlos Limpo Ting Xiong Yifan Rao Chorng Haur Sow Barbaros Ozyilmaz Department of Material Science&Engineering National University of SingaporeSingapore 117575Singapore Center for Advanced 2D Materials National University of SingaporeSingapore 117546Singapore Department of Physics National University of SingaporeSingapore 117551Singapore Institute forFunctional Intelligent Materials National University of SingaporeSingapore 117544Singapore

Despite advancements in silicon-based anodes for high-capacity lithium-ion batteries,their widespread commercial adoption is still hindered by significant volume expansion during cycling,especially at high active mass loadings crucial for practical *** root of these challenges lies in the mechanical instability of the material,which subsequently leads to the structural failure of the ***,we present a novel synthesis of a composite combining expanded graphite and silicon *** composite features a unique interlayer-bonded graphite structure,achieved through the application of a modified spark plasma sintering ***,this innovative structure not only facilitates efficient ion and electron transport but also provides exceptional mechanical strength(Vickers hardness:up to658 MPa,Young's modulus:11.6 GPa).This strength effectively accommodates silicon expansion,resulting in an impressive areal capacity of 2.9 mA h cm^(-2)(736 mA h g^(-1)) and a steady cycle life(93% after 100cycles).Such outsta nding performance is paired with features appropriate for large-scale industrial production of silicon batteries,such as active mass loading of at least 3.9 mg cm^(-2),a high-tap density electrode material of 1.68 g cm^(-3)(secondary clusters:1.12 g cm^(-3)),and a production yield of up to 1 kg per day.

关键词： Lithium-ion battery Silicon anode Spark plasma sintering Interlayer bonding Mechanical strength Tap density

Oils with different degree of saturation:effects on ileal digestibility of fat and corresponding additivity and bacterial community in growing pigs

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Journal of Animal Science and Biotechnology 2024年第4期15卷 1657-1668页

作者： lu Wang Yifan Chen Yuansen Yang Nuo Xiao Changhua lai State Key Laboratory of Animal Nutrition Ministry of Agriculture and Rural Affairs Feed Industry CentreChina Agricultural UniversityNo.2 Yuanmingyuan West RoadHaidian DistrictBeijing 100193China College of Animal Science and Technology Hebei Agricultural UniversityHebei 071000China

Background Oils are important sources of energy in pig *** combination of oils with different degree of saturation contributes to improve the utilization efficiency of the mixed oils and may reduce the cost of oil *** experiment was conducted to evaluate the effects of oils with different degree of saturation on the fat digestibility and corresponding additivity and bacterial community in growing *** Eighteen crossbred(Duroc×Landrace×Yorkshire)barrows(initial body weight:29.3±2.8 kg)were surgically fitted with a T-cannula in the distal *** experimental diets included a fat-free basal diet and 5 oil-added *** 5 oil-added diets were formulated by adding 6%oil with different ratio of unsaturated to saturated fatty acids(U:S)to the basal *** 5 oils were palm oil(U:S=1.2),canola oil(U:S=12.0),and palm oil and canola oil were mixed in different proportions to prepare a combination of U:S of 2.5,3.5 and 4.5,*** The apparent and standardized ileal digestibility(AID and SID)of fat and fatty acids increased linearly(Plues(P<0.05).The abundance of Romboutsia and Turicibacter in pigs fed diet containing palm oil was greater than that in rapeseed oil treatment group,and the two bacteria were negatively correlated with SID of C16:0,C18:0 and SFA(P<0.05).

关键词： Additivity Bacterial community Fat and fatty acids Growing pigs Ratio of unsaturated to saturated fatty acids Standardized ileal digestibility

Construction technology for deep tunnels crossing superhigh-temperature fault zones with high water surges

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Frontiers of Structural and Civil Engineering 2024年第8期18卷 1267-1280页

作者： yong ZHAO Tingyu ZHU Li YU Ming lu Sichuan–Xizang Railway Co. Ltd.Linzhi 860000China School of Civil Engineering Southwest Jiaotong UniversityChengdu 610036China

The harsh environment in tunnels with high geothermal temperatures and humidity can adversely impact machinery,personnel,and *** main causes of specific problems are the unknown mechanisms of local geothermal formation,inappropriate temperature control measures,and insufficient systematic *** this study,three work sections relating to a high geothermal tunnel are:the tunnel face,middle-of-tunnel section,and outside-oftunnel section.A cooling strategy is proposed to offer technical support in achieving comprehensive cooling,overall as well as for each of the ***,a comprehensive geological survey explores the mechanism and exact location of the heat ***,grouting and centralized drainage measures are used to control the heat release of hot *** ventilation,ice chillers and other applicable measures are used to control the ambient ***,a monitoring and early warning system is established to prevent *** cooling strategy has been applied in the field with good results.

关键词： high geothermal tunnels cooling strategy comprehensive cooling measures safety and security

Permanent Magnet Temperature Estimation for PMSMs Using Virtual Position-offset Injection

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CES Transactions on Electrical Machines and Systems 2024年第1期8卷 51-60页

作者： Beichen Ding Yuting lu Kaide Huang Guodong Feng Chunyan lai IEEE the School of Intelligent Systems Engineering Sun Yat-sen UniversityShenzhen 518107China the Fosan University Foshan 528225China the Department of Electrical and Computer Engineering Concordia UniversityQCCanada

This paper proposes a virtual position-offset injection based permanent magnet temperature estimation approach for permanent magnet synchronous machines(PMSMs). The concept of virtual position-offset injection is mathematically transforming the machine model to a virtual frame with a position-offset. The virtual frame temperature estimation model is derived to calculate the permanent magnet temperature(PMT) directly from the measurements with computation efficiency. The estimation model involves a combined inductance term, which can simplify the establishment of saturation compensation model with less measurements. Moreover, resistance and inverter distorted terms are cancelled in the estimation model, which can improve the robustness to the winding temperature rise and inverter distortion. The proposed approach can achieve simplified computation in temperature estimation and reduced memory usage in saturation compensation. While existing model-based approaches could be affected by either the need of resistance and inverter information or complex saturation compensation. Experiments are conducted on the test machine to verify the proposed approach under various operating conditions.

关键词： PMSM Magnet temperature estimation Virtual position offset injection Inverter nonlinearity

Synthesis of poly(thiourethane-alt-thioester)by alternating ring-opening copolymerization of N-thiocarboxyanhydrides and episulfides

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Science China Chemistry 2024年第9期67卷 3091-3097页

作者： Wei Xiong Tianjun Yue Haiwang lai Chunyan Lyu Weimin Ren Hua lu Beijing National Laboratory for Molecular Sciences Center for Soft Matter Science and EngineeringKey Laboratory of Polymer Chemistry and Physics of Ministry of EducationCollege of Chemistry and Molecular EngineeringPeking UniversityBeijing 100871China State Key Laboratory of Fine Chemicals Dalian University of TechnologyDalian 116081China

Polythiourethanes(PTU)and polythioesters(PTE)derived from renewable sources are emerging sustainable polymers for their excellent degradability and ***,P(TU-alt-TE)copolymers have been rare and challenging to ***,we report the efficient synthesis of novel P(TU-alt-TE)copolymers via the alternating copolymerization of N-thiocarboxyanhydrides(NTA)/episufides(ES)and provide mechanistic insight into the alternating chain propagation process via density functional theory(DFT)*** incorporation of ESs into traditional peptide backbone is capable of adjusting the glass transition temperature below thermal decomposition temperature,which confers better thermal processability by regulating the rigidity of the backbone and the hydrogen bond interaction among the polymer *** PTUs with tailored properties are accessible by altering the feeding ratio of NTAs and(bifunctional)***,the thiourethane in the backbone can endow interesting underwater adhesion properties to the *** the broad scope of NTA and ES monomers,this method is expected to provide a promising and general route to a wide range of P(TU-alt-TE)copolymers with diverse properties.

关键词： poly(thiourethane-alt-thioester) alternating ring-opening copolymerization N-thiocarboxyanhydrides episulfides

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