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1Transmission routes of 2019-nCoV and controlsin dental practice显示文摘A novel β-coronavirus(2019-nCoV) caused severe and even fatal pneumonia explored in a seafood market of Wuhan city, Hubei province, China, and rapidly spread to other provinces of China and other countries. The 2019-nCoV was different from SARS-Co V,but shared the same host receptor the human angiotensin-converting enzyme 2(ACE2). The natural host of 2019-nCoV may be the bat Rhinolophus affinis as 2019-nCoV showed 96.2% of whole-genome identity to Bat Co V Ra TG13. The person-to-person transmission routes of 2019-nCoV included direct transmission, such as cough, sneeze, droplet inhalation transmission, and contact transmission, such as the contact with oral, nasal, and eye mucous membranes. 2019-nCoV can also be transmitted through the saliva, and the fecal–oral routes may also be a potential person-to-person transmission route. The participants in dental practice expose to tremendous risk of 2019-nCoV infection due to the face-to-face communication and the exposure to saliva, blood, and other body fluids, and the handling of sharp instruments. Dental professionals play great roles in preventing the transmission of2019-nCoV. Here we recommend the infection control measures during dental practice to block the person-to-person transmission routes in dental clinics and hospitals.Xian Peng Xin Xu Yuqing Li Lei Cheng Xuedong Zhou Biao Ren 2020International Journal of Oral Science2020,12,1:29
2Safety threshold of high-speed railway pier settlement based on train-track-bridge dynamic interaction显示文摘This paper presents a method to determine the safety threshold of bridge pier settlement in high-speed railways.An analytical expression of the mapping relationship between the pier settlement and the rail deformation is derived theoretically for the double block ballastless track-bridge system.By adopting the superposition of the track random irregularity and the rail deformation caused by the pier settlement as the excitation inputs,the variations of vehicle dynamics indices with pier settlement are comparatively analyzed.Then,the safety threshold of the bridge pier settlement is obtained according to the limit of vehicle running safety and ride comfort indices of the high-speed trains.Results show that the dynamics indices of different trains have different sensitivities to the pier settlement,and the train CRH2C is the most sensitive one among all the types of Chinese high-speed trains.When passing through the bridges in common span with pier settlement at the speed of 250–350 km/h,the trains suffer the low-frequency excitations,and the vertical acceleration of car body is most sensitive to the pier settlement of all the dynamics indices.When the car body vertical acceleration just exceeds the allowable limit,the critical settlement value is 23.4 mm,which is much bigger than the pier differential settlement limit in the current code for Chinese high-speed railways.CHEN Zhao Wei ZHAI Wan Ming CAI Cheng Biao SUN Yu 2015Science China(Technological Sciences)2015,58,2:26
3A PP2C-1 Allele Underlying a Quantitative Trait Locus Enhances Soybean l O0-Seed Weight显示文摘栽培大豆可以在驯服期间失去某有用基因 loci。从野大豆的基因的基因渗入能拓宽基因背景并且改进大豆农学的特点。在这研究,通过 recombinant 的整个染色体的定序,生来的线人口源于在野大豆 ZYD7 和栽培大豆 HN44 之间的一个十字,并且为种子重量量的特点 loci 印射,我们发现从野大豆 ZYD7 的磷酸酶 2C-1 ( PP2C-1 )等位基因在种子重量/尺寸贡献增加。PP2C-1 可以由提高覆盖物的房间尺寸并且激活一个子集完成这功能播种特点相关的基因。我们发现 PP2C-1 与 GmBZR1 被联系, Arabidopsis BZR1 的大豆 ortholog,之一在发信号的 brassinosteroid (BR ) 给抄写因素调音,并且便于 dephosphorylated GmBZR1 的累积。相反,有在 N 终点的一些氨基酸的变化的 PP2C-2 等位基因没展出这功能。而且,我们证明 GmBZR1 能在转基因的植物支持种子重量 / 尺寸。通过栽培大豆就职的分析,我们发现 40% 检验就职没有 PP2C-1 等位基因,建议这些就职能被这等位基因的介绍改进。一起拿,我们的学习识别精英等位基因 PP2C-1,它能在由分子帮助繁殖的这等位基因的那操作可以增加的大豆,和针尖提高种子重量或尺寸在大豆的生产和另外的荚 / 庄稼。Xiang Lu Qing Xiong Tong Cheng Qing-Tian Li Xin-Lei Liu Ying-Dong Bi Wei Li Wan-Ke Zhang Biao Ma Yong-Cai Lai Wei-Guang Du Wei-Qun Man Shou-Yi Chen Jin-Song Zhang 2017Molecular Plant2017,10,5:17
4COVID-19 Super Spreading Event Amongst Elderly Individuals—Jilin Province,China,January 2021显示文摘Summary What is already known on this topic?Clusters of COVID-19 cases often happened in small settings(e.g.,families,offices,school,or workplaces)that facilitate person-to-person virus transmission,especially from a common exposure.What is added by this report?On January 10 and 11,2021,an individual gave three product promotional lectures in Tonghua City.Laishun Yao Mingyu Luo Tiewu Jia Xingang Zhang Zhulin Hou Feng Gao Xin Wang Xiaogang Wu Weihua Cheng Guoqian Li Jing Lu Bing Zhao Tao Li Enfu Chen Dapeng Yin Biao Huang 2021China CDC weekly2021,3,10:13
5Efficacy and safety of the long-acting fusion inhibitor albuvirtide in antiretroviral-experienced adults with human immunodeficiency virus-1:interim analysis of the randomized,controlled,phase 3,non-inferiority TALENT study显示文摘Background:Albuvirtide is a once-weekly injectable human immunodeficiency virus(HIV)-1 fusion inhibitor.We present interim data for a phase 3 trial assessing the safety and efficacy of albuvirtide plus lopinavir-ritonavir in HIV-1-infected adults already treated with antiretroviral drugs.Methods:We carried out a 48-week,randomized,controlled,open-label non-inferiority trial at 12 sites in China.Adults on the World Health Organization(WHO)-recommended first-line treatment for>6 months with a plasma viral load>1000 copies/mL were enrolled and randomly assigned(1:1)to receive albuvirtide(once weekly)plus ritonavir-boosted lopinavir(ABT group)or the WHO-recommended second-line treatment(NRTI group).The primary endpoint was the proportion of patients with a plasma viral load below 50 copies/mL at 48 weeks.Non-inferiority was prespecified with a margin of 12%.Results:At the time of analysis,week 24 data were available for 83 and 92 patients,and week 48 data were available for 46 and 50 patients in the albuvirtide and NRTI groups,respectively.At 48 weeks,80.4%of patients in the ABT group and 66.0%of those in the NRTI group had HIV-1 RNA levels below 50 copies/mL,meeting the criteria for non-inferiority.For the per-protocol population,the superiority of albuvirtide over NRTI was demonstrated.The frequency of grade 3 to 4 adverse events was similar in the two groups;the most common adverse events were diarrhea,upper respiratory tract infections,and grade 3 to 4 increases in triglyceride concentration.Renal function was significantly more impaired at 12 weeks in the patients of the NRTI group who received tenofovir disoproxil fumarate than in those of the ABT group.Conclusions:The TALENT study is the first phase 3 trial of an injectable long-acting HIV drug.This interim analysis indicates that once-weekly albuvirtide in combination with ritonavir-boosted lopinavir is well tolerated and non-inferior to the WHO-recommended second-line regimen in patients with first-line treatment failure.Trial registration:ClinicalTrials.gov Identifier:NCT02369965;http://gffzz90ed6ce9d87f4798soowk6qbkvkkf6u5p.ffgz.tsg.suse.edu.cn Clinical Trial Registry No.ChiCTR-TRC-14004276;http://gffzz62a03ee25e6f4a77hoowk6qbkvkkf6u5p.ffgz.tsg.suse.edu.cn/enindex.aspx.Bin Su Cheng Yao Qing-Xia Zhao Wei-Ping Cai Min Wang Hong-Zhou Lu Yuan-Yuan Chen Li Liu Hui Wang Yun He Yu-Huang Zheng Ling-Hua Li Jin-Feng Chen Jian-Hua Yu Biao Zhu Min Zhao Yong-Tao Sun Wen-Hui Lun Wei Xia Li-Jun Sun Li-Li Dai Tai-Yi Jiang Mei-Xia Wang Qing-Shan Zheng Hai-Yan Peng Yao Wang Rong-Jian Lu Jian-Hua Hu Hui Xing Yi-Ming Shao Dong Xie Tong Zhang Fu-Jie Zhang Hao Wu TALENT Study Team 2020Chinese Medical Journal2020,,24:10
6Oral microbiota in human systematic diseases显示文摘Oral bacteria directly affect the disease status of dental caries and periodontal diseases. The dynamic oral microbiota cooperates with the host to reflect the information and status of immunity and metabolism through two-way communication along the oral cavity and the systemic organs. The oral cavity is one of the most important interaction windows between the human body and the environment.The microenvironment at different sites in the oral cavity has different microbial compositions and is regulated by complex signaling,hosts, and external environmental factors. These processes may affect or reflect human health because certain health states seem to be related to the composition of oral bacteria, and the destruction of the microbial community is related to systemic diseases. In this review, we discussed emerging and exciting evidence of complex and important connections between the oral microbes and multiple human systemic diseases, and the possible contribution of the oral microorganisms to systemic diseases. This review aims to enhance the interest to oral microbes on the whole human body, and also improve clinician’s understanding of the role of oral microbes in systemic diseases. Microbial research in dentistry potentially enhances our knowledge of the pathogenic mechanisms of oral diseases,and at the same time, continuous advances in this frontier field may lead to a tangible impact on human health.Xian Peng Lei Cheng Yong You Chengwei Tang Biao Ren Yuqing Li Xin Xu Xuedong Zhou 2022International Journal of Oral Science2022,14,1:9
7Platelet-rich plasma accelerates skin wound healing by promoting re-epithelialization显示文摘Background:Autologous platelet-rich plasma(PRP)has been suggested to be effective for wound healing.However,evidence for its use in patients with acute and chronic wounds remains insufficient.The aims of this study were to comprehensively examine the effectiveness,synergy and possible mechanism of PRP-mediated improvement of acute skin wound repair.Methods:Full-thickness wounds were made on the back of C57/BL6 mice.PRP or saline solution as a control was administered to the wound area.Wound healing rate,local inflammation,angiogenesis,re-epithelialization and collagen deposition were measured at days 3,5,7 and 14 after skin injury.The biological character of epidermal stem cells(ESCs),which reflect the potential for re-epithelialization,was further evaluated in vitro and in vivo.Results:PRP strongly improved skin wound healing,which was associated with regulation of local inflammation,enhancement of angiogenesis and re-epithelialization.PRP treatment significantly reduced the production of inflammatory cytokines interleukin-17A and interleukin-1β.An increase in the local vessel intensity and enhancement of re-epithelialization were also observed in animals with PRP administration and were associated with enhanced secretion of growth factors such as vascular endothelial growth factor and insulin-like growth factor-1.Moreover,PRP treatment ameliorated the survival and activated the migration and proliferation of primary cultured ESCs,and these effects were accompanied by the differentiation of ESCs into adult cells following the changes of CD49f and keratin 10 and keratin 14.Conclusion:PRP improved skin wound healing by modulating inflammation and increasing angiogenesis and re-epithelialization.However,the underlying regulatory mechanism needs to be investigated in the future.Our data provide a preliminary theoretical foundation for the clinical administration of PRP in wound healing and skin regeneration.Pengcheng Xu Yaguang Wu Lina Zhou Zengjun Yang Xiaorong Zhang Xiaohong Hu Jiacai Yang Mingying Wang Binjie Wang Gaoxing Luo Weifeng He Biao Cheng 2020Burns & Trauma2020,8,1:8
8Oral bacteria colonize and compete with gut microbiota in gnotobiotic mice显示文摘The oral microbiota is associated with oral diseases and digestive systemic diseases.Nevertheless,the causal relationship between them has not been completely elucidated,and colonisation of the gut by oral bacteria is not clear due to the limitations of existing research models.The aim of this study was to develop a human oral microbiota-associated (HOMA) mouse model and to investigate the ecological invasion into the gut.By transplanting human saliva into germ-free (GF) mice,a HOMA mouse model was first constructed.16S rRNA gene sequencing was used to reveal the biogeography of oral bacteria along the cephalocaudal axis of the digestive tract.In the HOMA mice,84.78% of the detected genus-level taxa were specific to the donor.Principal component analysis (PCA) revealed that the donor oral microbiota clustered with those of the HOMA mice and were distinct from those of specific pathogen-free (SPF) mice.In HOMA mice,OTU counts decreased from the stomach and small intestine to the distal gut.The distal gut was dominated by Streptococcus,Veillonella,Haemophilus,Fusobacterium,Trichococcus and Actinomyces.HOMA mice and human microbiota-associated (HMA) mice along with the GF mice were then cohoused.Microbial communities of cohoused mice clustered together and were significantly separated from those of HOMA mice and HMA mice.The Source Tracker analysis and network analysis revealed more significant ecological invasion from oral bacteria in the small intestines,compared to the distal gut,of cohoused mice.In conclusion,a HOMA mouse model was successfully established.By overcoming the physical and microbial barrier,oral bacteria colonised the gut and profiled the gut microbiota,especially in the small intestine.Bolei Li Yang Ge Lei Cheng Benhua Zeng Jinzhao Yu Xian Peng Jianhua Zhao Wenxia Li Biao Ren Mingyun Li Hong Wei Xuedong Zhou 2019International Journal of Oral Science2019,11,3:7
9Effect analysis of chemoradiotherapy after operation in patients with stage ⅢA non-small cell lung cancer显示文摘Objective:To investigate the effect of chemoradiotherapy after surgery onⅢA stage nonsmall cell lung cancer(NSCLC).Methods:A total of 156 NSCLC patients undergoing total pneumonectomy or pulmonary lobectomy were included in this study.The chemotherapy group (n=75) received the protocol of cisplatin(DDP) + gemcitabine(GEM) / docetaxel(DOC) / vinorelbine (NVB);the radiotherapy + chemotherapy group(n=81) received sequential chemoradiotherapy. The response rale,local control rale in1 to 2 years,overall survival(OS),progression-free survival(PFS) and adverse reactions were evaluated.Results:The overall response rate was obviously higher in radiotherapy + chemotherapy group(79.4%) than in chemotherapy group(56.8%) (P<0.01).The 1 year local control rates for chemotherapy group and radiotherapy + chemotherapy group were(69.1±7.9)%and(77.8±8.2)%respectively and the difference reached statistical significance (P<0.001).The 2 year local control rates were(42.1±6.1%and(61.5±6.9)%respectively(P<0.001). The difference in median follow-up time between the two groups did not reach statistical meaning(P>0.05),while the median PFS of two groups were 10.8 months and 16.9 months respectively(P<0.001).1-year and 3-year survival rates were obviously higher in radiotherapy + chemotherapy group than in chemotherapy group,and the difference reached statistical significance(P<0.05 or P<0.01).The adverse reactions manifested as hematological toxicity and digestive tract reaction in the two groups.In the radiotherapy + chemotherapy group,incidences of radiation-induced esophagus injury and lung injury were 24.7%and 34.6%respectively,all occurring within 2 to 6 weeks after the start of radiation and both below grade 2.Conclusions: Chemoradiotherapy after surgery can improve local control rate and reduce or prevent distant metastasis,but there are still many controversies.In clinical work,we should carefully evaluate each patient’s age,lung function,basic physical condilion scoring and complications to choose a therapeutic schedule that is suitable for the patient.Sheng Chen Yu-Ling Cheng Shi-Ting Li Yao-Jun Ni Biao Gu 2012Asian Pacific Journal of Tropical Medicine2012,5,10:6
10A Facile Synthesis of β-Cyclodextrin Monoaldehyde显示文摘β -Cyclodextrin (β -CD) was directly oxidized in high yield to the corresponding monoaldehyde by cyclized 2-iodoxybenzoic acid (IBX) in DMSO.Jing HU Cheng Feng YE Yong De ZHAO Jun Biao CHANG Rui Yun GUO(Lanzhou Institute of Chemical Physics, Chinese Academy of Scences Lanzhou 730000)(Henan Institute of Chemistry, Zhengzhou 450002) 1999Chinese Chemical Letters1999,10,4:6
11Soybean miR172a Improves Salt Tolerance and Can Function as a Long-Distance Signal显示文摘Wen-Jia Pan Jian-Jun Tao Tong Cheng Xiao-Hua Bian Wei Wei Wan-Ke Zhang Biao Ma Shou-Yi Chen Jin-Song Zhang 2016Molecular Plant2016,9,9:5
12Regenerative medicine in China:main progress in different fields显示文摘Regenerative medicine(RM) is an emerging interdisciplinary field of research and China has developed the research quickly and impressed the world with numerous research findings in stem cells,tissue engineering,active molecules and gene therapy.Important directions are induced differentiation of induced pluripotent stem and embryo stem cells as well as somatic stem cell differentiation potential and their application in trauma,burns,diseases of aging and nerve regeneration.The products Activ Skin and bone repair scaffolds have been approved and are applied in the clinic,and similar products are being studied.About 10 engineered growth-factor drugs for repair and regeneration have been approved and are used in the clinic.Gene therapy,therapeutic cloning and xenotransplantation are some of the strategies being studied.However,China needs to develop standards,regulations and management practices suitable for the healthy development of RM.Aspects that should be strengthened include sound administrative systems,laws,and technical specifications and guidelines;conservation of stem cell resources;emphasis on training and retention of talented stem cell researchers;and reasonable allocation of resources,diversification of investment and breakthroughs in key areas.Finally,broad and deep international cooperation is necessary.Biao Cheng Shu-Liang Lu Xiao-Bing Fu 2016Journal of Medical Colleges of PLA(China)2016,31,3:5
13Combustion synthesis and magnetic investigation of nanosized CoFe_2O_4显示文摘Nanosized Co spinel ferrite was prepared by a combustion method. The grain size of resultant ferrite can becontrolled by the reaction conditions. Magnetic investigation revealed that the products with an average grain size of 4 nm behave as superparamagnetic materials and have zero coercive force; whereas the samples with an average grain size of 85 nm (near the size of critical single domain) have the maximal coercive force. There were the negative magnetic intergrain interactions which became stronger when the grain size neared that of the single domain.XU Zhigang, CHENG Fuxiang, ZHOU Biao, LIAO Chunsheng & YAN ChunhuaState Key Laboratory of Rare Earth Materials Chemistry and Applications, PKU-HKU Joint Laboratory on Rare Earth Materials and Bioin-organic Chemistry, Peking University, Beijing 100871, China 2001Chinese Science Bulletin2001,46,5:4
14Effects of atomization parameters of dust removal nozzles on the de-dusting results for different dust sources显示文摘In order to obtain appropriate spray pressure and enhance the spraying and dust removal efficiency, various factors including the dust characteristics, nozzle spraying angle, effective spraying range, water consumption and droplet size are taken into account. The dust characteristics from different mines and atomization parameters of different pressure nozzles were measured. It was found that the internal pressure of coal cutters and roadheaders should be kept at 2 MPa, which could ensure large droplet size, large spraying angle and low water consumption and hence realizing a large-area covering and capture for large particle dusts. However, the external spray pressure should be kept at 4 MPa for smaller droplet size and longer effective spraying range, leading to effective dust removal in the operator zone. The spray pressure of support moving, drawing opening, and stage loader on a fully mechanized caving face and stage loader on a fully mechanized driving face should be kept at 8 MPa, under which the nozzles have long effective spraying range, high water flow and small droplet size for the rapid capture of instantaneous, high-concentration and small size dust groups. From the applications on the caving and driving faces in the coal mines, it is indicated that the optimization of spray pressure in different spraying positions could effectively enhance dust removal efficiency. Selecting appropriate nozzles according to the dust characteristics at different positions is also favorable for dust removal efficiency. With the selected nozzles under optimal pressures, the removal rates of both total dust and respirable dust could reach over70%, showing a significant de-dusting effect.Cheng Weimin Ma Youying Yang Junlei Sun Biao 2016International Journal of Mining Science and Technology2016,26,6:4
15Highly Regioselective Sequential 1,1-Dihydrosilylation of Terminal Aliphatic Alkynes with Primary Silanes显示文摘Summary of main observation and conclusion A regioselective double 1,1-hydrosilylation of terminal aliphatic alkynes with primary silanes catalyzed by one cobalt catalyst has been developed. gem-Bis(dihydrosilyl)alkanes containing four silicon-hydrogen bonds are efficiently constructed in an atom-economical man ner. Tolerated substrates include simplest alkyne-ethyne, a complicated drug derivative and various functi on alized terminal aliphatic alkynes. Asymmetric approach using two catalysts is achieved with excelle nt enan tioselectivities to access corresp on ding chiral products. The tra nsformations of Si—H bonds into Si—C, Si—O, and Si —F bonds and the synthesis of enantioriched a-hydroxysilane show synthetic utility.Zhaoyang Cheng Shipei Xing Jun Guo Biao Cheng Lan-Fang Hu Xing-Hong Zhang Zhan Lu 2019Chinese Journal of Chemistry2019,37,5:4
16Clinical significance of germline copy number variation in susceptibility of human diseases显示文摘Germline copy number variation(CNV) is considered to be an important form of human genetic polymorphisms. Previous studies have identified amounts of CNVs in human genome by advanced technologies, such as comparative genomic hybridization, single nucleotide genotyping, and high-throughput sequencing. CNV is speculated to be derived from multiple mechanisms, such as nonallelic homologous recombination(NAHR) and nonhomologous end-joining(NHEJ). CNVs cover a much larger genome scale than single nucleotide polymorphisms(SNPs), and may alter gene expression levels by means of gene dosage, gene fusion, gene disruption, and long-range regulation effects, thus affecting individual phenotypes and playing crucial roles in human pathogenesis. The number of studies linking CNVs with common complex diseases has increased dramatically in recent years. Here, we provide a comprehensive review of the current understanding of germline CNVs, and summarize the association of germline CNVs with the susceptibility to a wide variety of human diseases that were identified in recent years. We also propose potential issues that should be addressed in future studies.Liwen Hu Xinyue Yao Hairong Huang Zhong Guo Xi Cheng Yang Xu Yi Shen Biao Xu Demin Li 2018Journal of Genetics and Genomics2018,45,1:4
17Protective effect of Chushizi(Fructus Broussonetiae)on acetaminophen-induced rat hepatitis by inhibiting the Toll-like receptor 3/c-Jun N-terminal kinase/c-jun/c-fos/janus protein tyrosine kinase/activators of transcription 3 pathway显示文摘OBJECTIVE:To observe the intervention of Chushizi(Fructus Broussonetiae)(CSZ)on drug-induced liver injury(DILI)in rats,as well as indicators of liver function,serum levels of inflammatory cytokines,and expression of proteins and m RNA associated with toll-like receptor 3(TLR3)and the signal transducer and activator of transcription 3(STAT3)pathway in the liver[TLR3,janus protein tyrosine kinase 2(JAK2),c-jun,c-fos,c-Jun N-terminal kinase 2(JNK2),and STAT3].METHODS:Forty specified pathogen free grade Sprague-Dawley rats were randomly divided into the control group,the model group,the silybin group and the CSZ group.Rats were given acetaminophen(APAP)to trigger DILI.Histopathology of the liver was observed by hematoxylin-eosin staining.The levels of alanine aminotransferase(ALT),aspartate transaminase(AST),direct bilirubin(DBIL),and total bilirubin(TBIL)in serum were detected by a semi-automatic biochemical instrument.Content of tumor necrosis factor alpha(TNF-α),interleukin(IL)-6,IL-13,and IL-22 in serum were detected by the enzyme-linked immunosorbent assay,the expression of TLR3,phosphorylation of JAK2(p-JAK2),while c-jun and c-fos proteins in the liver were determined by immunohistochemistry;expression of JNK2,and STAT3 in the liver were assayed by Western blot and real-time quantitative polymerase chain reaction.P-JNK2 and p-STAT3 in the liver were assayed by Western blot.RESULTS:After treatment,the activity of ALT,AST,and concentrations of TBIL,DBIL,TNF-α,IL-6,as well as IL-13 in serum,were lower than those in the model group,and expression of p-JAK2,TLR3,c-jun,c-fos,p-STAT3,and p-JNK2 could be downregulated.CONCLUSION:Our findings suggest that CSZ is a valid medicine to alleviate APAP-induced DILI,while its partial mechanism may regulate the TLR3/JNK/c-jun/c-fos/JAK/STAT3 pathway.Zhang Yandong Biao Yaning Chu Xinqiao Hao Lei Shi Cheng Liu Yu Zhang Yixin Wang Xi 2020Journal of Traditional Chinese Medicine2020,40,6:4
18A frequency and amplitude dependent model of rail pads for the dynamic analysis of train-track interaction显示文摘A frequency and amplitude dependent model is used to describe the complex behavior of rail pads.It is implemented into the dynamic analysis of three dimensional coupled vehicle-slab track(3D-CVST)systems.The vehicle is treated as a 35-degreeof-freedom multi-body system,and the slab track is represented by two continuous Bernoulli-Euler beams supported by a series of elastic rectangle plates on a viscoelastic foundation.The rail pad model takes into account the influences of the excitation frequency and of the displacement amplitude through a fractional derivative element,and a nonlinear friction element,respectively.The Grünwald representation of the fractional derivatives is employed to numerically solve the fractional and nonlinear equations of motion of the 3D-CVST system by means of an explicit integration algorithm.A dynamic analysis of the3D-CVST system exposed to excitations of rail harmonic irregularities is primarily carried out,which reveals the dependence of stiffness and damping on excitation frequency and displacement amplitude.Subsequently,sensitive analyses of the model parameters are investigated by conducting the dynamic analysis of the 3D-CVST system subjected to excitations of welded rail joint irregularities.Following this,parameters of the rail pad model are optimized with respect to experimental values.For elucidation,the 3D-CVST dynamic model incorporated with the rail pads model is used to calculate the wheel/rail forces induced by excitations of measured random track irregularities.Further,the numerical results are compared with experimental data,demonstrating the reliability of the proposed model.ZHU Sheng Yang CAI Cheng Biao LUO Zhen LIAO Zhong Qi 2015Science China(Technological Sciences)2015,58,2:4
19Highway constructions on the Qinghai-Tibet Plateau:Challenge,research and practice显示文摘Highway constructions on the Qinghai-Tibet Plateau(QTP)face great challenges induced by the unique local environmental,geological,and engineering conditions.The large area of permafrost,great temperature variability,strong UV rays,and complex geological conditions are the major factors that adversely influence the longterm performance of pavement systems.Since 1960s,Chinese engineers and researchers have started conducting research on the QTP to enhance the performance and durability of pavement systems.The present paper provide a comprehensive review of challenge,research and practice of highway constructions on the QTP including the special environmental and geological conditions,history of highway constructions on the QTP,major challenges and the state-of-the-art technology of subgrade constructions on permafrost,developments of the pavement structures and materials,performance prediction and maintenance methods of pavement surfaces,and applications of the research achievements on the first expressway on the QTP(i.e.,Gongyu Expressway).Based on the comprehensive literature review,it can be found that(1)frost heave and thaw weakening induced subgrade disease and longitudinal cracks on the pavement surface are complex coupled water-thermal-load problems.Engineering solutions are focusing on active cooling and thermal insulation methods,which can help to reduce temperature variations in the subgrade and thus improving its stability,(2)the harsh environmental and construction conditions may reduce the early strength and induce premature damage of cement-treated base materials.Some field validations showed that geocell-reinforced or asphalt-treated flexible base materials can provide better long-term performance,(3)the large temperature variability and strong UV rays can significantly accelerate aging of asphalt binders and greatly reduce the service life of asphalt mixtures.Various binder modification methods were developed for improving their viscoelasticity and enhance the low-temperature cracking resistance of pavement surface materials but are still lack of field validation data and comparisons of their life cycle costs.Therefore,it is recommended that a demonstration research project build test sections to examine a range of pavement structures and materials,and compare their long-term performance and life cycle costs,which can serve as important reference for future highway constructions on the QTP.Aimin Sha Biao Ma Hainian Wang Liqun Hu Xuesong Mao Xilan Zhi Huaxin Chen Yu Liu Feng Ma Zhuangzhuang Liu Rui He Wei Si Xuhao Wang Cheng Li 2022Journal of Road Engineering2022,2,1:4
20Observation of double indirect interlayer exciton in MoSe_(2)/WSe_(2) heterostructure显示文摘Interlayer excitons(IXS)are electron–hole pairs bound in the spatial separation layer by the Coulomb effect,and their lifetime is several orders of magnitude longer than that of direct excitons,providing an essential platform for long-lived exciton devices.The recent emergence of the van der Waals heterostructure(HS),which combines two layers of different transitional metal dichalcogenides(TMDs),has created new opportunities for IX research.Herein,we demonstrate the observation of double indirect interlayer excitons in the MoSe_(2)/WSe_(2)HS using photoluminescence(PL)spectroscopy.The intensities of the two peaks are essentially the same,and the energy difference is 22 meV,which is perfectly in line with the calculation result of density functional theory.Furthermore,the experience of variable excitation power also proves that the splitting of the IXs originates from the conduction band spin-splitting of MoSe_(2).The observation results provide a promising platform for further exploring the new physical properties and optoelectronic phenomena of TMD HS.Biao Wu Yunpeng Wang Jiahong Zhong Cheng Zeng Yassine Madoune Wanting Zhu Zongwen Liu Yanping Liu 2022Nano Research2022,15,3:3
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