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Sustainable production of high-energy-density jet fuel via cycloaddition reactions

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Journal of Energy Chemistry 2024年第8期95卷 712-722,I0016页

作者： yan-Cheng Hu Yingying zhao Ning Li Jing-Pei Cao School of Chemical Engineering and Technology China University of Mining and TechnologyXuzhou 221116JiangsuChina School of Education Science Jiangsu Normal UniversityXuzhou 221116JiangsuChina CAS Key Laboratory of Science and Technology on Applied Catalysis Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023LiaoningChina

Developing an energy supply-chain based on renewable biomass holds great potential to build a low carbon ***-energy-density(HED)jet fuel,featuring unique fused/strained cycloalkanes,is of great significance for volume-limited military aircrafts,as their high density and combustion heat can extend flight duration and increase the ***,the exploration of biomass-based routes towards HED fuel has drawn much attention over the past *** reaction features rapid construction of various carbocycles in an atom-and step-economical *** elegant strategy has been widely applied in the manufacture of sustainable HED *** we carefully summarize the progress achieved in this fascinating area and the review is categorized by the cycloaddition patterns including[4+2],[2+2],[4+4],and[2+1]***,the energy densities of the as-prepared biofuels and petroleumbased fuels(conventional Jet-A and advanced JP-10)are also *** review will provide important insights into rational design of new HED fuel with different ring-types/sizes and inspire the chemists to turn those literature studies into practical applications in military field.

关键词： High-energy-density fuel Biomass-based chemicals Cycloaddition Cycloalkanes Catalysis

Data delivery delay and cross-layer packet size analysis for reliable transmission of Licklider transmission protocol in space networks

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Science China(Information Sciences) 2024年第9期67卷 229-244页

作者： Guannan yanG Ruhai WANG Kanglian zhao Wenfeng LI Dong yan School of Information Engineering Nanjing University of Finance and Economics Drayer Department of Electrical and Computer Engineering Lamar University School of Electronic Science and Engineering Nanjing University Beijing Aircraft Overall Design Department

Delay/disruption tolerant networking(DTN) is proposed as a networking architecture to overcome challenging space communication characteristics for reliable data transmission service in presence of long propagation delays and/or lengthy link disruptions. Bundle protocol(BP) and Licklider Transmission Protocol(LTP) are the main key technologies for DTN. LTP red transmission offers a reliable transmission mechanism for space networks. One of the key metrics used to measure the performance of LTP in space applications is the end-to-end data delivery delay, which is influenced by factors such as the quality of spatial channels and the size of cross-layer packets. In this paper, an end-to-end reliable data delivery delay model of LTP red transmission is proposed using a roulette wheel algorithm, and the roulette wheel algorithm is more in line with the typical random characteristics in space networks. The proposed models are validated through real data transmission experiments on a semi-physical testing platform. Furthermore, the impact of cross-layer packet size on the performance of LTP reliable transmission is analyzed, with a focus on bundle size, block size, and segment size. The analysis and study results presented in this paper offer valuable contributions towards enhancing the reliability of LTP transmission in space communication scenarios.

关键词： Licklider transmission protocol DTN bundle protocol cross-layer packets size space communication

Trajectory of COVID-19 response and management strategy in China:scientific rationale driven strategy adjustments

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Frontiers of Medicine 2024年第1期18卷 19-30页

作者： Zeyu Zhang Yue yan Lina zhao Yizhou Bian Ning zhao You Wu Dahai zhao Zongjiu Zhang Institute for Hospital Management Tsinghua UniversityBeijing100084China School of Medicine Tsinghua UniversityBeijing100084China School of International and Public Affairs Shanghai Jiao Tong UniversityShanghai200030China Yale University-Shanghai Jiao Tong University Joint Center for Health Policy Shanghai Jiao Tong UniversityShanghai200030China

The pneumonia caused by novel coronavirus SARS-CoV-2 infection in early December 2019,which was later named coronavirus disease 2019(COVID-19)by the World Health Organization(WHO),rapidly spread across the *** has made extraordinary efforts to this unprecedented pandemic,put its response and control at a very high level of infectious disease management(Category B but with measures for Category A),given top priority to the people and their lives,and balanced the pandemic control and socio-economic *** more than three years’fighting against this disease,China downgraded the management of COVID-19 to Category B infectious disease on January 8,2023 and the WHO declared the end of public health emergency on May 5,***,the ending of pandemic does not mean that the disease is no longer a health *** against COVID-19 from China and the whole world should be learned to prepare well for the future public health *** article gives a systematic review of the trajectory of COVID-19 development in China,summarizes the critical policy arrangements and provides evidence for the adjustment during policy making process,so as to share experiences with international community and contribute to the global health for all humanity.

关键词： COVID-19 public health response and control strategy science-based policy making

Glacial-interglacial cycles recorded in clay minerals from the eastern Tibetan Plateau over the last 800 ka and their indications

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Science China Earth Sciences 2024年第7期67卷 2162-2177页

作者： Xiaoyan ZHANG chunxia ZHANG yan zhao Bin HU Zhengtang GUO Key Laboratory of Cenozoic Geology and Environment Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijing 100049China College of Earth Science and Engineering Shandong University of Science and TechnologyQingdao 266590China Key Laboratory of Land Surface Pattern and Simulation Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China

Clay mineral proxies have been widely used to reconstruct changes in provenance and the ***,high-altitude clay mineral indications and long-term and orbital variations have not been fully ***,we present an800-ka clay-mineral record from a lacustrine sediment core(ZB13-C2)from the Zoige Basin on the eastern Tibetan Plateau(TP).X-ray diffraction and scanning electron microscopy were used to identify the clay mineral assemblages and their micromorphological characteristics of core *** results revealed that the clay minerals in core ZB13-C2 are mainly illite,with small amounts of chlorite,kaolinite,and smectite(including irregular mixed-layers of illite-smectite(I/S)and chloritesmectite(C/S)).The clay mineral assemblages and proxies exhibit three stages of change,which are mainly controlled by the Zoige watershed range under different climate *** watershed was limited to the southeastern region with altitudes ranging from~3500 to~4200 meters above sea level(m a.s.l.),and glacial-interglacial hydraulic erosion controlled the input of bedrock debris during 800-621 ka *** expanded to higher altitudes(~4200 to~4700 m a.s.l.)due to stronger seasonal freezethaw weathering without significant glacial-interglacial variations under a cooling and drying climate during 621-100 ka ***,it expanded to its highest altitudes of~4700 to~5200 m *** of the watershed after 100 ka BP,and hydraulic erosion increased obviously under a warm climate of the interstadial MIS 3 on the *** watershed underwent two major expansions under different climatic conditions at~621 ka and 100 ka BP,with the wet/dry alternation became strong at~621 ka *** results reveal that long-term temperature changes and the wet/dry alternation at high altitudes controlled the watershed range and degree of the physical erosion,and that the indications of clay minerals should be carefully clarified before they are used as climate indicators,especi

关键词： Quaternary Zoige Basin Lacustrine sediments Paleoenvironment Weathering

Patterns, processes, and differentiation mechanisms of China's transition from old to new economic drivers

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Journal of Geographical Sciences 2024年第9期34卷 1697-1718页

作者： yan Mingtao zhao Jianji yan Mingyue Key Research Institute of Yellow River Civilization and Sustainable Development Henan UniversityKaifeng 475001HenanChina Collaborative Innovation Center on Yellow River Civilization Jointly Built by Henan Province and Ministry of Education Henan UniversityKaifeng 475001HenanChina College of Cultural and Tourism Henan UniversityKaifeng 475001HenanChina

Transition from old to new economic drivers(TONED) is of great significance for optimizing economic structures. Using a combination of methods including entropy weight technique for order preference by similarity to ideal solution, geospatial analysis, and optimal parameter geodetector, this study investigates the patterns and mechanisms of China's TONED in the prefecture-level cities from 2011 to 2020. The findings reveal that(1) the TONED exhibited a spatial distribution characterized by higher levels in the east and lower levels in the west, along with a pyramidal hierarchy of levels. The distribution of hot and cold spots roughly followed the Heihe-Yulin line.(2) The informatization levels, openness to the outside world, and urbanization played a dominant role in the TONED. The types of dual-factor interactions exhibited both dual-factor enhancement and non-linear enhancement effects.(3) The eastern and central regions were more likely to promote the TONED through enhanced informatization levels, whereas the western region relied more on increasing openness. This study finds that the TONED results from the combined effects of three geographical natures, each playing a distinct role. The recommendations provided can serve as a reference for China and other developing countries to implement the TONED in the context of deglobalization.

关键词： transition from old to new economic drivers pattern evolution differentiation mechanism geographical nature China

Clinical study on microscopic syndrome differentiation and traditional Chinese medicine treatment for liver stomach disharmony in chronic gastritis

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World Journal of Gastrointestinal Surgery 2024年第5期16卷 1377-1384页

作者： chun-yan Bai Wei Tian Qian Zhang Department of Rehabilitation Medicine Beijing Aerospace General HospitalBeijing 100076China Department of Rehabilitation Medicine People’s Hospital of HengshuiHengshui 053000Hebei ProvinceChina Department of Internal Medicine Hebei Academy of Chinese Medicine SciencesShijiazhuang 050000Hebei ProvinceChina

BACKGROUND Chronic gastritis(CG)is a common gastrointestinal disorder characterized by inflammation of the stomach ***-stomach disharmony(LSD)syndrome is believed to contribute to CG *** To evaluate the efficacy and safety of microcosmic syndrome differentiation and Chinese herbal medicine(CHM)treatment in patients with CG and LSD *** Sixty-four patients with CG and LSD syndrome were randomly divided into two groups:The treatment group received CHM based on microcosmic syndrome differentiation and the control group received conventional Western *** treatment course lasted 12 *** primary outcome was improvement in dyspeptic symptoms,measured using the Nepean Dyspepsia *** secondary outcomes included the improvement rate of endoscopic findings,histopathological findings,and microcosmic syndrome scores and the incidence of adverse *** After 12 wk of treatment,the treatment group showed significantly greater improvement in dyspeptic symptoms than the control group(93.75%vs 65.63%,P0.05).No serious adverse events were observed in either *** Microcosmic syndrome differentiation and CHM treatment can effectively improve dyspeptic symptoms and endoscopic findings in patients with CG and LSD syndrome and have a good safety *** studies with larger sample sizes and longer follow-up periods are required to confirm the long-term efficacy and mechanism of action of this treatment.

关键词： Chronic gastritis Liver-stomach disharmony Microcosmic syndrome differentiation Chinese herbal medicine Randomized controlled trial Microcosmic syndrome scores

Numerical Study on the Effect of Gap Diffraction on the Hydrodynamic Performance of A Floating Breakwater

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China Ocean Engineering 2024年第4期38卷 663-675页

作者： BIAN Xiang-qian JI chun-yan XU Sheng GUO Jian-ting HUO Fa-li School of Naval Architecture and Ocean Engineering Jiangsu University of Science and TechnologyZhenjiang 212100China

Two-dimensional(2D)flume experiments are useful in investigating the performances of floating breakwaters(FBs),including hydrodynamic performances,motion responses,and mooring *** a reasonable gap between the flume wall and the FBs is a critical step in 2D flume ***,research on the effect of the gap on the accuracy of 2D FB experimental results is *** address this issue,a numerical wave tank is developed using CFD to estimate the wave-FB interaction of a moored dual-cylindrical FB,and the results are compared to experimental data from a previously published *** is good agreement between them,indicating that the numerical model is sufficiently *** numerical model is then applied to explore the effect of gap diffraction on the performance of FBs in2D *** was discovered that the nondimensional gap length L_(Gap)/W_(Pool)should be smaller than 7.5%to ensure that the relative error of the transmission coefficient is smaller than 3%.The influence of the gap is also related to the entering wave properties,such as the wave height and period.

关键词： floating breakwater diffraction effect gap hydrodynamic performance model experiments CFD numerical simulation

Significantly Enhanced Melt Memory Effect of Metallocene-made Isotactic Polypropylene Containing Talc

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Chinese Journal of Polymer Science 2024年第2期42卷 213-222,I0008页

作者： Hong-Wen Sun Fu-Shan Wang yan Gao Fu-Qing Wei Jia-chun Feng State Key Laboratory of Molecular Engineering of Polymers Department of Macromolecular ScienceFudan UniversityShanghai200433China Lanzhou Petrochemical Corporation of PetroChina Lanzhou730060China Lanzhou Petrochemical Research Center Petrochemical Research Institute of PetroChinaLanzhou730060China

The melt memory effect is a widely observed phenomenon in semi-crystalline polymers. In practical applications, various additives are usually introduced into polymers, which may affect their melt memory behavior. In this work, the effect of talc on the melt memory effect of metallocene-made isotactic polypropylene(M-PP) was investigated in detail by using the differential scanning calorimetry. The results indicated that the introduction of talc significantly strengthened the melt memory effect of M-PP. Specifically, the upper limit temperature of Domain II increased from 161 ℃ to 174 ℃, resulting in a substantial widening of the temperature range of Domain IIa from 1 ℃ to 14 ℃. Analysis of the crystal orientation of the M-PP containing talc cooled from various Ts suggested that the remarkably enhanced melt memory effect could be ascribed to the stabilization of oriented nuclei facilitated by talc. This stabilizing effect was likely attributable to the prefreezing effect or the sorption interaction between talc and the M-PP chains.

关键词： Metallocene-made isotactic polypropylene Talc Melt memory effect Crystal orientation

Understanding the spatial interaction of ultrasounds based on three-dimensional dual-frequency ultrasonic field numerical simulation

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China Foundry 2024年第1期21卷 29-43页

作者： zhao-yang Yin Qi-chi Le yan-chao Jiang Da-zhi zhao Qi-yu Liao Qi Zou Key Lab of Electromagnetic Processing of Materials Ministry of EducationNortheastern UniversityShenyang 110819China School of Materials Science and Engineering Northeastern UniversityShenyang 110819China

A transient 3D model was established to investigate the effect of spatial interaction of ultrasounds on the dual-frequency ultrasonic field in magnesium alloy *** effects of insertion depth and tip shape of the ultrasonic rods,input pressures and their ratio on the acoustic field distribution were discussed in ***,the spacing,angle,and insertion depth of two ultrasonic rods significantly affect the interaction between distinct *** a result,various acoustic pressure distributions and cavitation regions are *** spherical rods mitigate the longitudinal and transversal attenuation of acoustic pressure and expand the cavitation volume by 53.7%and 31.7%,respectively,compared to the plate and conical *** the input pressure will enlarge the cavitation region but has no effect on the acoustic pressure distribution *** acoustic pressure ratio significantly affects the pressure distribution and the cavitation region,and the best cavitation effect is obtained at the ratio of 2:1(P15:P20).

关键词： dual-frequency ultrasonic numerical model acoustic pressure spatial interaction magnesium alloy