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Research on the Dynamic Compressibility of Polyurethane Microcellular Elastomer and its Application for Impact Resistance

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Chinese Journal of Polymer Science 2024年第8期42卷 1185-1197页

作者： Zhi-ying Zhao hao jiang Xiao-Dong li Xu-Dong Zhang Xing Su Mei-Shuai Zou School of Materials Science and Engineering Beijing Institute of TechnologyBeijing 100081China

The packaging materials with cushioning performance are used to prevent the internal contents from being damaged by the impact and vibration of external *** polyurethane microcellular elastomers(PUMEs)can absorb energy through cell collapse and molecular chain *** this study,PUMEs with different densities were investigated by scanning electron microscopy,dynamic mechanical analysis and dynamic compression *** exhibited significant im pact resistance and the maximum peak stress attenuation ratio reached 73.33%.The protective equipment was made by PUME with the optimal density of 600 kg/m^(3),and then the acceleration sensing device installed with the same protective equipment fell from a height of 3,5 and 10 m to evaluate the energy-absorbing property and reusability of *** results showed that PUMEs equipment reduced the peak acceleration of the device by 93.84%,with a maximum deviation of 9%between actual test and simulation,and shortened the impact time of first landing by 57.39%.In addition,the equipment PUMEs equipment could effectively reduce the stress on the protected items.

关键词： Polyurethane microcellular elastomer Impact velocity Stress attenuation ratio Impact resistance

Constructing inter-diffusive PtCuNi/WO_(3)interface to enhance the catalytic activity and stability in oxygen reduction

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Tungsten 2024年第2期6卷 293-303页

作者： hao-Zhe Xu Dong li ying Chen Pin Fang Xiao-Xing Ke Olga Demidenko Yu-Jing li Beijing Key Laboratory of Construction Tailorable Advanced Functional Materials and Green Applications Experimental Center of Advanced MaterialsSchool of Materials Science and EngineeringBeijing Institute of TechnologyBeijing 100081China Faculty of Materials and Manufacturing Beijing University of TechnologyBeijing 100124China Scientifi c-Practical Materials Research Centre National Academy of Sciences of Belarus220072 MinskBelarus

Platinum-group-metal-based alloy nanocrystals have been considered as the most effi cient catalysts for oxygen reduction reaction(ORR).However,the poor stability issues limit their further deployment in *** oxide(WO_(3))has received attention due to its intrinsic electrochemical stability and proton absorption/desorption *** this work,we prepared PtCuNi/WO_(3)/C hybrid catalyst with inter-diff usive alloy/WO_(3)interface on *** catalyst exhibits enhanced activity and stability associated with the WO_(3)*** characterization results suggest that the increased activity originates from the complementary proton supply of non-stoichiometric H_(x)WO_(3).Moreover,WO_(3)prevents the particle from dissolution and detachment under vigorous electrochemical *** enhanced stability originates from the electronic interaction established between Pt and *** work provides new strategies to design high-performance ORR catalysts by taking the merits of WO_(3)。

关键词： Tungsten oxide PtCuNi Interface Electronic interaction

Noncovalent cross-linked engineering hydrogel with low hysteresis and high sensitivity for flexible self-powered electronics

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Journal of Energy Chemistry 2024年第7期94卷 136-147页

作者： Hang Yuan Shaowei Han jia Wei Songwei li Peipei Yang hao-Yang Mi Chuntai liu Changyu Shen National Engineering Research Center for Advanced Polymer Processing Technology Key Laboratory of Materials Processing and Mold(Ministry of Education)Zhengzhou UniversityZhengzhou450002HenanChina Yunnan TobaccoQuality Inspection&Supervision Station Kunming 650106YunnanChina

In this study,the hydrogel network was reinforced by covalent-like hydrogen bonding,and the strong binding ability of boron-nitrogen coordination served as the main driving *** them,acrylamide(AM)and 3-acrylamidophenylboronic acid(AAPBA)were the main body,and the numerous hydroxyl groups in the trehalose(Treh)molecule and other polymer groups formed strong hydrogen bonding interactions to improve the mechanical properties of the PAM/PAAPBA/Treh(PAAT)hydrogel and ensured the simplicity of the synthesis *** hydrogel possessed high strain at break(1239%),stress(64.7 kPa),low hysteresis(100%to 500%strain,corresponding to dissipation energy from 1.37 to 7.80 kJ/m^(3)),and outstanding cycling stability(retained more than 90%of maximum stress after 200 ten-sile cycles).By integrating carbon nanotubes(CNTs)into PAAT hydrogel(PAATC),the PAATC hydrogel with excellent strain response performance was successfully *** PAATC conductive hydro-gel exhibited high sensitivity(gauge factor(GF)=10.58 and sensitivity(S)=0.304 kPa^(-1)),wide strain response range(0.5%-1000%),fast response time(450 ms),and short recovery time(350 ms),excellent fatigue resistance,and strain response ***,the PAATC-based triboelectric nanogener-ator(TENG)displayed outstanding energy harvesting performance,which shows its potential for appli-cation in self-powered electronic devices.

关键词： Low hysteresis Covalent-like hydrogen bonding Boron-nitrogen coordination Hydrogel sensor Triboelectric nanogenerator

Effect of strain on structure and electronic properties of monolayer C_(4)N_(4)

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Chinese Physics B 2024年第5期33卷 595-600页

作者：陈昊徐瑛赵家石周丹 School of Physics Changchun University of Science and TechnologyChangchun 130022China School of Computer Science and Technology Changchun University of Science and TechnologyChangchun 130022China

The first-principles calculations are performed to examine structural,mechanical,and electronic properties at large strain for a monolayer C_(4)N_(4),which has been predicted as an anchoring promising material to attenuate shuttle effect in li–S batteries stemming from its large absorption energy and low diffusion energy *** results show that the ideal strengths of C_(4)N_(4)under tension and pure shear deformation conditions reach 13.9 GPa and 12.5 GPa when the strains are 0.07 and 0.28,*** folded five-membered rings and diverse bonding modes between carbon and nitrogen atoms enhance the ability to resist plastic deformation of C_(4)N_(4).The orderly bond-rearranging behaviors under the weak tensile loading path along the[100]direction cause the impressive semiconductor–metal transition and inverse semiconductor–metal *** present results enrich the knowledge of the structure and electronic properties of C_(4)N_(4)under deformations and shed light on exploring other two-dimensional materials under diverse loading conditions.

关键词： two-dimensional materials strain effect structural evolution electronic properties

Mechanical characteristics and reservoir stimulation mechanisms of the Gulong shale oil reservoirs, the northern Songliao Basin

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Petroleum Science 2024年第3期21卷 2023-2036页

作者： Si-Wei Meng jia-Ping Tao Tian-jiao li Dong-Xu li Su-ling Wang liu Yang Xin liu li-hao liang He liu PetroChina Research Institute of Petroleum Exploration Development Beijing100083China National Key Laboratory of Continental Shale Oil Daqing 163002HeilongjiangChina Dalian University of Technology Dalian116024LiaoningChina PetroChina Daqing Oilfield Co.Ltd. Daqing163002HeilongjiangChina Northeast Petroleum University Daqing163002HeilongjiangChina China University of Mining and Technology(Beijing) Beijing100083China

Shale oil of the Qingshankou Formation of the Gulong Sag,the northern Songliao Basin,represents the first attempt at large-scale development of pure-shale-type shale oil in *** integrating the multiscale refined reservoir characterization with macro-micro-scale mechanical testing,it is clarified that the Gulong shale is characterized by high clay mineral content,high rock plasticity,highly-developed bedding,and prominent mechanical anisotropy.A three-dimensional(3D)fracture propagation model of hydraulic fracturing was built for the Gulong shale,which fully captures the hydraulic fracture distribution pattern affected by the high bedding density,in-situ stress,and fracturing treatment *** research showed that due to influences of bedding,hydraulic fracturing in the Gulong shale forms a complex fracture morphology featuring the main fracture with multiple perpendicular branches that have different lengths(like the outdoor directional TV antenna);however,the vertical propagation of fractures is inhibited,and the fracture height is commonly less than 10 *** limited stimulated reservoir volume(SRV)is the main problem facing the fracturing stimulation of the Gulong shale *** density has vital effects on fracture morphology,so case-specific fracturing designs shall be developed for shale intervals with different bedding development *** reservoirs with welldeveloped bedding,it is suggested to properly increase the perforation cluster spacing and raise the volume and proportions of viscous fluids of the pad,so as to effectively promote vertical fracture propagation and improve reservoir stimulation *** study integrates multi-scale fine reservoir characterization and macro-micro-scale mechanical testing,as well as the construction and numerical simulation of hydraulic fracturing models for high-density layered shale reservoirs,providing a new approach and methodological framework for the fracturing research of high-density layer

关键词： Shale oil Hydraulic fracturing High bedding density Fracture propagation model

One-pot and One-step Cu(0)-mediated Reversible-Deactivation Radical Polymerization of N-Isopropylacrylamide(NIPAM) in Water

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Chinese Journal of Polymer Science 2024年第1期42卷 1-6,I0004页

作者： Zi-Shan li Jing Lyu Bei Qiu ying-hao li Ruth Foley Ri-jian Song Melissa Johnson Qiang Geng Wen-Xin Wang Institute of Precision Medicine(AUST-IPM) Anhui University of Science and TechnologyHuainan 232001China Charles Institute of Dermatology School of MedicineUniversity College DublinDublin D04 V1W8Ireland

Copper(0)-mediated reversible-deactivation radical polymerization(Cu(0)-mediated RDRP) of the water-soluble monomer Nisopropylacrylamide(NIPAM) has been challenging with the problems of high dispersity, poor control over the molecular weights(MWs) or complex or multi reaction steps, etc. In this work, we report the well-controlled polymerization of NIPAM in water via a facile one-pot and one-step Cu(0)-mediated RDRP. The results of this approach show that the key for kicking off the Cu(0)-mediated NIPAM RDRPs is to ensure sufficient Cu~I at the very beginning, and the key to achieve a well-controlled chain growth is to provide adequate deactivation strength during the polymerization process. For NIPAM, which has a high propagation rate constant, the deactivation control can be effectively enhanced by extra adding deactivator(i.e., Cu~II) to the system. Moreover, a low reaction temperature(4 ℃) is necessary in the controlled synthesis of higher MW poly(Nisopropylacrylamide)(PNIPAM) to avoid the compromise in control caused by the phase transition from its lower critical solution temperature(LCST). Through this new kinetically controlled strategy, PNIPAMs with well-defined structure, narrow molecular weight distributions(MWDs) and varied MWs were successfully achieved.

关键词： Cu(0)-mediated RDRP N-isopropylacrylamide Propagation Deactivation Reaction parameters

Ketogenic diet therapy in children with epilepsy caused by SLC2A1 mutations:a single-center single-arm retrospective study

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World Journal of Pediatrics 2024年第5期20卷 517-524页

作者： ying-Yan Wang Yun-Qing Zhou li-Juan Luo Cui-Jin Wang Nan Shen hao li Ji-Wen Wang Department of Neurology Shanghai Children’s Medical CenterSchool of MedicineShanghai Jiao Tong UniversityShanghaiChina Department of Infectious Diseases Shanghai Children’s Medical CenterSchool of MedicineShanghai Jiao Tong UniversityShanghaiChina Clinical Research Ward Clinical Research CenterShanghai Children’s Medical CenterSchool of MedicineShanghai Jiao Tong UniversityShanghaiChina

Background This retrospective study assessed the efficacy and safety of ketogenic diet therapies in children with epilepsy caused by SLC2A1 genetic mutations and glucose transporter type 1 deficiency *** Pediatric patients with epilepsy symptoms admitted to our medical center between January 2017 and October 2021 were included if they presented with an SLC2A1 genetic mutation on whole-exome *** analyzed the patients’convulsions and treatment with antiepileptic *** patients were followed up at different time periods after ketogenic diet *** Six patients with SLC2A1 mutations were included in this *** patients had seizures of different types and frequencies,and they took antiepileptic drugs to relieve their *** were then treated with a ketogenic diet for at least four *** analyzed epilepsy control rates at 1,2,3,6,and 12 months after ketogenic diet *** patients were seizure-free within a month of receiving the diet *** patients were followed up for six months,three were followed up for 12 months after the treatment,and there was no recurrence of epilepsy during this *** antiepileptic drug withdrawal,none of the patients experienced seizure relapse when receiving ketogenic diet treatment *** severe adverse events occurred during the *** Ketogenic diet therapy is very effective and safe for the treatment of epilepsy caused by SLC2A1 ***,patients with glucose transporter type 1 deficiency syndrome caused by SLC2A1 mutations should begin ketogenic diet treatment as soon as possible.

关键词： Epilepsy Glucose transporter type 1 Ketogenic diet SLC2A1

A compact X-band backward traveling-wave accelerating structure

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Nuclear Science and Techniques 2024年第5期35卷 13-29页

作者： Xian-Cai lin hao Zha jia-Ru Shi Qiang Gao Fang-Jun Hu Qing-Zhu li Huai-Bi Chen Department of Engineering Physics Tsinghua UniversityBeijing 100084China Key Laboratory of Particle and Radiation Imaging(Tsinghua University) Ministry of EducationBeijing 100084China

Very high-energy electrons(VHEEs)are potential candidates for FLASH radiotherapy for deep-seated *** proposed a compact VHEE facility based on an X-band high-gradient high-power *** this study,we investigated and realized the first X-band backward traveling-wave(BTW)accelerating structure as the buncher for a VHEE facility.A method for calculating the parameters of single cell from the field distribution was introduced to simplify the design of the BTW ***-domain circuit equations were applied to calculate the transient beam parameters of the buncher in the unsteady state.A prototype of the BTW structure with a thermionic cathode-diode electron gun was designed,fabricated,and tested at high power at the Tsinghua X-band high-power test *** structure successfully operated with 5-MW microwave pulses from the pulse compressor and outputted electron bunches with an energy of 8 MeV and a pulsed current of 108 mA.

关键词： Backward traveling-wave accelerating structure Equivalent circuit model High-power test Very high-energy electron radiotherapy

The Crystallization Behavior of L-Poly(lactic acid)/Polypropylene Blends:The Acceleration for Both L-Poly(lactic acid)and Polypropylene

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Chinese Journal of Polymer Science 2024年第6期42卷 775-786页

作者： Shuang-Cheng li Wei-jia Zhou Wen-Jie Wu Jun Shao Shui-liang Chen hao-Qing Hou Sheng Xiang College of Chemistry&Chemical Engineering and Nanofiber Engineering Center of jiangxi Province Jiangxi Normal UniversityNanchang330022China National Engineering Research Center for Carbohydrate Synthesis/Key Lab of Fluorine and Silicon for Energy Materials and Chemistry of Ministry of Education Jiangxi Normal UniversityNanchang330022China Wenzhou Institute University of Chinese Academy of SciencesWenzhou325001China

For a polymer/polymer dismissible blend with two crystallizable components,the crystallization behavior of different components and the reciprocal influences between different crystals are interesting and important,but did not investigate in *** this study,the L-poly(lactic acid)/polypropylene(PLLA/PP)blends with different weight ratios were prepared by melt mixing and the crystallization behavior of the blends were *** showed that the crystalline structures of PLLA and PP were not altered by the *** the crystallization of PLLA,both the diffusion of chain segments and crystallization rate were enhanced under the existence of PP *** the crystallization of PP,its crystallization rate was depressed under the existence of amorphous PLLA molecular *** the PP crystallized from the existence of PLLA crystals,although the diffusion rate of PP was reduced by PLLA crystals,the nucleation positions were obviously enhanced,which accelerated the formation of PP *** investigation would supply more basic data for the application of PLLA/PP blend.

关键词： L-poly(lactic acid) Polypropylene Blends Crystalization behavior Crystallization acceleration