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| 1 | The possibility of using all-sky meteor radar to observe ionospheric E-region field-aligned irregularities显示文摘All-sky meteor radars are primarily used for meteor observations. This paper reports the first observations of ionospheric Eregion field-aligned irregularities(FAIs) from a conventional all-sky meteor radar located at Wuhan(31°N, 114°E) for the period of March–June 2018. E-region FAI echoes evident in range-time intensity(RTI) maps show quasiperiodic striations with positive and negative slopes, which are consistent with multiple FAI structures moving across the wide beam of the meteor radar. A statistical analysis shows that out of a total of 111 d, there are 73 d with E-region FAI echoes detected by the meteor radar. The FAI events correspond well with the presence of sporadic-E layers which provide the necessary plasma density gradient for the development of gradient drift instability producing FAIs. The results demonstrate the capability of conventional meteor radars to make simultaneous routine observations of meteors and ionospheric E-region FAIs through incorporating RTI and spectral analysis into the online realtime data processing. Meteor radar observations could potentially address the limitations of ionospheric radars, which cannot provide simultaneous measurements of neutral winds and irregularity structures, and thereby contribute to better understanding of the dynamical processes producing E-region irregularities. | XIE HaiYong LI GuoZhu NING BaiQi REID Iain HU LianHuan WU BaoYuan YU You YANG SiPeng | 2019 | Science China(Technological Sciences)2019，62，8： | 3 |
| 2 | Perfectly Matched Layer for an Elastic Parabolic Equation Model in Ocean Acoustics显示文摘The perfectly matched layer(PML) is an effective technique for truncating unbounded domains with minimal spurious reflections. A fluid parabolic equation(PE) model applying PML technique was previously used to analyze the sound propagation problem in a range-dependent waveguide(Lu and Zhu, 2007). However, Lu and Zhu only considered a standard fluid PE to demonstrate the capability of the PML and did not take improved one-way models into consideration. They applied a [1/1] Padé approximant to the parabolic equation. The higher-order PEs are more accurate than standard ones when a very large angle propagation is considered. As for range-dependent problems, the techniques to handle the vertical interface between adjacent regions are mainly energy conserving and single-scattering. In this paper, the PML technique is generalized to the higher order elastic PE, as is to the higher order fluid PE. The correction of energy conserving is used in range-dependent waveguides. Simulation is made in both acoustic cases and seismo-acoustic cases. Range-independent and range-dependent waveguides are both adopted to test the accuracy and efficiency of this method. The numerical results illustrate that a PML is much more effective than an artificial absorbing layer(ABL) both in acoustic and seismo-acoustic sound propagation modeling. | XU Chuanxiu ZHANG Haigang PIAO Shengchun YANG Shi’e SUN Sipeng TANG Jun | 2017 | Journal of Ocean University of China2017，16，1： | 3 |
| 3 | Sex disparity of lung cancer risk in non-smokers:a multicenter population-based prospective study based on China National Lung Cancer Screening Program显示文摘Background: Non-smokers account for a large proportion of lung cancer patients, especially in Asia, but the attention paid to them is limited compared with smokers. In non-smokers, males display a risk for lung cancer incidence distinct from the females-even after excluding the influence of smoking;but the knowledge regarding the factors causing the difference is sparse. Based on a large multicenter prospective cancer screening cohort in China, we aimed to elucidate the interpretable sex differences caused by known factors and provide clues for primary and secondary prevention.Methods: Risk factors including demographic characteristics, lifestyle factors, family history of cancer, and baseline comorbidity were obtained from 796,283 Chinese non-smoking participants by the baseline risk assessment completed in 2013 to 2018. Cox regression analysis was performed to assess the sex difference in the risk of lung cancer, and the hazard ratios (HRs) that were adjusted for different known factors were calculated and compared to determine the proportion of excess risk and to explain the existing risk factors.Results: With a median follow-up of 4.80 years, 3351 subjects who were diagnosed with lung cancer were selected in the analysis. The lung cancer risk of males was significantly higher than that of females;the HRs in all male non-smokers were 1.29 (95% confidence interval [CI]: 1.20-1.38) after adjusting for the age and 1.38 (95% CI: 1.28-1.50) after adjusting for all factors, which suggested that known factors could not explain the sex difference in the risk of lung cancer in non-smokers. Known factors were 7% (|1.29-1.38|/1.29) more harmful in women than in men. For adenocarcinoma, women showed excess risk higher than men, contrary to squamous cell carcinoma;after adjusting for all factors, 47% ([1.30-1.16]/[1.30-1]) and 4% ([7.02-6.75]/[7.02-1])) of the excess risk was explainable in adenocarcinoma and squamous cell carcinoma. The main causes of gender differences in lung cancer risk were lifestyle factors, baseline comorbidity, and family history.Conclusions: Significant gender differences in the risk of lung cancer were discovered in China non-smokers. Existing risk factors did not explain the excess lung cancer risk of all non-smoking men, and the internal causes for the excess risk still need to be explored;most known risk factors were more harmful to non-smoking women;further exploring the causes of the sex difference would help to improve the prevention and screening programs and protect the non-smoking males from lung cancers. | Zheng Wu Fengwei Tan Zhuoyu Yang Fei Wang Wei Cao Chao Qin Xuesi Dong Yadi Zheng Zilin Luo Liang Zhao Yiwen Yu Yongjie Xu Jiansong Ren Jufang Shi Hongda Chen Jiang Li Wei Tang Sipeng Shen Ning Wu Wanqing Chen Ni Li Jie He | 2022 | Chinese Medical Journal2022，，11： | 3 |
| 4 | First results of optical meteor and meteor trail irregularity from simultaneous Sanya radar and video observations显示文摘Meteoroids entering the Earth's atmosphere can create meteor trail irregularity seriously disturbing the background ionosphere. Although numerous observations of meteor trail irregularities were performed with VHF/UHF coherent scatter radars in the past, no simultaneous radar and optical instruments were employed to investigate the characteristics of meteor trail irregularity and its corresponding meteoroid. By installing multiple video cameras near the Sanya VHF radar site, an observational campaign was conducted during the period from November 2016 to February 2017. A total of 242 optical meteors with simultaneous non-specular echoes backscattered from the plasma irregularities generated in the corresponding meteor trails were identified. A good agreement between the angular positions of non-specular echoes derived from the Sanya radar interferometer and those of optical meteors was found,validating that the radar system phase offsets have been properly calibrated. The results also verify the interferometry capability of Sanya radar for meteor trail irregularity observation. The non-specular echoes with simultaneous optical meteors were detected at magnetic aspect angles greater than ~78°. Based on the meteor visual magnitude estimated from the optical data, it was found that the radar nonspecular echoes corresponding to brighter meteors survived for longer duration. This could provide observational evidence for the significance of meteoroid mass on the duration of meteor trail irregularity. On the other hand, the simultaneous radar and video common-volume observations showed that there were some cases with optical meteors but without radar non-specular echoes. One possibility could be that some of the optical meteors appeared at extremely low altitudes where meteor trail irregularities rarely occur. | GuoZhu Li BaiQi Ning Ao Li SiPeng Yang XiuKuan Zhao BiQiang Zhao WeiXing Wan | 2018 | Earth and Planetary Physics2018，2，1： | 3 |
| 5 | Global COVID-19 Pandemic Waves: Limited Lessons Learned Worldwide over the Past Year显示文摘The occurrence of coronavirus disease 2019(COVID-19)was followed by a small burst of cases around the world;afterward,due to a series of emergency non-pharmaceutical interventions(NPIs),the increas-ing number of confirmed cases slowed down in many countries.However,the lifting of control measures by the government and the public’s loosening of precautionary behaviors led to a sudden increase in cases,arousing deep concern across the globe.arousing deep concern across the globe.This study evaluates the situation of the COVID-19 pandemic in countries and territories worldwide from January 2020 to February 2021.According to the time-varying reproduction number(R(t))of each country or territory,the results show that almost half of the countries and territories in the world have never controlled the epidemic.Among the countries and territories that had once contained the occurrence,nearly half failed to maintain their prevention and control,causing the COVID-19 pandemic to rebound across the world—resulting in even higher waves in half of the rebounding countries or territories.This work also proposes and uses a time-varying country-level transmission risk score(CTRS),which takes into account both R(t)and daily new cases,to demonstrate country-level or territory-level transmission potential and trends.Time-varying hierarchical clustering of time-varying CTRS values was used to successfully reveal the countries and territories that contributed to the recent aggravation of the global pandemic in the last quarter of 2020 and the beginning of 2021,and to identify countries and territories with an increasing risk of COVID-19 transmission in the near future.Furthermore,a regression analysis indicated that the introduction and relaxation of NPIs,including workplace closure policies and stay-at-home requirements,appear to be associated with recent global transmission changes.In conclu-sion,a systematic evaluation of the global COVID-19 pandemic over the past year indicates that the world is now in an unexpected situation,with limited lessons learned.Summarizing the lessons learned could help in designing effective public responses for constraining future waves of COVID-19 worldwide. | Yongyue Wei Jinxing Guan Xiao Ning Yuelin Li Liangmin Wei Sipeng Shen Ruyang Zhang Yang Zhao Hongbing Shen Feng Chen | 2022 | Engineering2022，8，6： | 1 |
| 6 | Influence of Ar/N_2 Flow Rate on Structure and Property for TaN/NbN Multilayered Coatings显示文摘有 nanoscale 双性人层时期的 TaN/NbN multilayered 涂层被 RF (收音机频率)以不同 Ar/N2 流动率综合磁控管 sputtering.XRD (X光检查衍射) andNano Indenter 系统被采用调查 Ar/N2 流动率的影响(F_( Ar ):F_( N2 ))在微观结构和机械性质上涂层。低角度的 XRD 模式显示了定义 awell 的作文调整和 multilayered 涂层的层结构。所有 multilayered 涂层几乎比 rule-of-mixtures 价值揭示了更高的坚硬整体黝黑并且 NbNcoatings.At F_( Ar ):F_( N2 ) =10 , multilayered 涂层拥有了理想的坚硬,有弹性的模量,内部压力,和破裂抵抗,在另外的 Ar/N2 flowrates.The 与相比综合了有强壮的混合的分层的结构黝黑( 110 ),( 111 ),( 200 )并且 Nb2N ( 101 )质地应该与提高的机械性质有关。 | Xuehua ZHANG Yuanbin KANG Sipeng LIU Qiang LI Ying YANG Xiangyun DENG Dejun LI | 2007 | Journal of Materials Science & Technology2007，23，4： | 1 |
| 7 | Transmission dynamics model and the coronavirus disease 2019 epidemic:applications and challenges显示文摘Since late 2019,the beginning of coronavirus disease 2019(COVID-19)pandemic,transmission dynamics models have achieved great development and were widely used in predicting and policymaking.Here,we provided an introduction to the history of disease transmission,summarized transmission dynamics models into three main types:compartment extension,parameter extension and population-stratified extension models,highlight the key contribution of transmission dynamics models in COVID-19 pandemic:estimating epidemiological parameters,predicting the future trend,evaluating the effectiveness of control measures and exploring different possibilities/scenarios.Finally,we pointed out the limitations and challenges lie ahead of transmission dynamics models. | Jinxing Guan Yang Zhao Yongyue Wei Sipeng Shen Dongfang You Ruyang Zhang Theis Lange Feng Chen | 2022 | Medical Review2022，2，1： | 0 |
| 8 | Mixed boundary conditions for piezoelectric plates显示文摘For plate bending and stretching problems in piezoelectric materials,the reciprocal theorem and the general solution of piezoelasticity are applied in a novel way to obtain the appropriate mixed boundary conditions accurate to all order.A decay analysis technique is used to establish necessary conditions that the prescribed data on the edge of the plate must satisfy in order that it should generate a decaying state within the plate.For the case of axisymmetric bending and stretching of a circular plate,these decaying state conditions are obtained explicitly for the first time when the mixed conditions are imposed on the plate edge.They are then used for the correct formulation of boundary conditions for the interior solution. | GAO Yang 1 ,XU SiPeng 2 &ZHAO BaoSheng 3 1College of Science,China Agricultural University,Beijing 100083,China 2College of Engineering,Ocean University of China,Qingdao 266071,China 3 School of Mechanical Engineering,University of Science and Technology of Liaoning,Anshan 114044,China | 2009 | Science China(Physics,Mechanics & Astronomy)2009，52，5： | 0 |
| 9 | Flow characteristics of radial inflow in impeller rear cavity with baffle plate显示文摘The research purpose of this paper is to explore the influence of the baffle plate on the airflow in the rear cavity of the centrifugal impeller and optimize the performance of the secondary air system’s air bleed section.In this paper,a comprehensive experimental study was carried out on the flow characteristics in the impeller rear cavity with baffle plate.The windage torque,flow structure and pressure drop between inlet and outlet were measured respectively.The experiment was carried out with the condition that the range of rotational Reynolds number was from 8.33×10^(5)to 22.2×10^(5)and the range of mass flow rate coefficient was from 0.92×10^(4)to 2.92×10^(4).The results show that the static cavity and the narrow stator-rotor cavity formed by the baffle plate effectively suppress the overall swirl coefficient in the cavity.Thus,the static pressure and total pressure drop in the rotor-stator cavity were reduced.The influence of the baffle plate on the windage torque of the rotary disk is related to the turbulence parameters.Under large turbulence parameters,the windage torque would be reduced with baffle plate,while under small turbulence parameters,the baffle plate would increase with baffle plate.In general,the baffle plate can improve the flow capacity and optimize the bleed air performance with proper structure and operation conditions. | Yang BAI Xiang LUO Dongdong LIU Zeyu WU Xiaoqiang ZHANG Sipeng WANG | 2024 | Chinese Journal of Aeronautics2024，37，2： | 0 |
| 10 | Approaches to Improving Selectivity During Photoelectrochemical Transformation of Small Molecules显示文摘Photoelectrochemical (PEC) small-molecule oxidation can selectively transform substrates into high-value-added fine chemicals and increase the rate of cathode hydrogen evolution. Nevertheless, achieving high-selectivity PEC oxidation of small molecules to produce specific products is a very challenging task. In general, selectivity can be improved by changing the surface catalyticsites of the photoanode and modulating the interfacial environments of the reactions. Herein, recent advances in approaches to improving selective PEC oxidation of small molecules are introduced. We first briefly discuss the basic concept and fundamentals of small-molecule PEC oxidation. The reported approaches to improving the performance of selective PEC oxidation of small molecules are highlighted from two aspects: (1) changing the surface properties of photoanodes by selecting suitable materials or modifying the photoanodes and (2) mediating the oxidation reactions using redox mediators. The PEC oxidation mechanism of these studies is emphasized. We also discuss the challenges in this research direction and offer a perspective on the further development of selective PEC-based small-molecule transformation. | Sipeng Yang Jie Yang Mengyu Duan Shirong Kang Shaohua He Chuncheng Chen | 2024 | Transactions of Tianjin University2024，30，2： | 0 |
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