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ERROR ESTIMATION FOR NUMERICAL METHODS USING THE ULTRA WEAK VARIATIONAL FORMULATION IN MODEL OF NEAR FIELD SCATTERING PROBLEM

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Journal of Computational Mathematics 2014年第5期32卷 491-506页

作者： tian luan Fuming Ma Minghui Liu School of Mathematics and Statistics Beihua University Jilin 132013 China Institute of Mathematics Jilin University Changchun 130012 China

In this paper, we investigate the use of ultra weak variational formulation to solve a wave scattering problem in near field optics. In order to capture the sub-scale features of waves, we utilize evanescent wave functions together with plane wave functions to approximate the local properties of the field. We analyze the global convergence and give an error estimation of the method. Numerical examples are also presented to demonstrate the effectiveness of the strategy.

关键词： Helmholtz equation Ultra weak variational formulation Plane wave function,Evanescent wave function Absorbing boundary condition.

Below-Cloud Aerosol Scavenging by Different-Intensity Rains in Beijing City

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Journal of Meteorological Research 2019年第1期33卷 126-137页

作者： tian luan Xueliang GUO tianhang ZHANG Lijun GUO State Key Laboratory of Severe Weather Chinese Academy of Meteorological SciencesChina Meteorological Administration Key Laboratory for Cloud Physics Chinese Academy of Meteorological SciencesChina Meteorological Administration Collaborative Innovation Center for Meteorological Disasters Forecast Early Warning and AssessmentNanjing University of Information Science &Technology National Meteorological Center China Meteorological Administration

Below-cloud aerosol scavenging process by precipitation is important for cleaning the polluted aerosols in the atmosphere, and is also a main process for acid rain formation. However, the related physical mechanism has not been well documented and clarified yet. In this paper, we investigated the below-cloud PM_(2.5)(particulate matter with aerodynamic diameter being 2.5 μm or less) scavenging by different-intensity rains under polluted conditions characterized by high PM_(2.5) concentrations, based on in-situ measurements from March 2014 to July 2016 in Beijing city. It was found that relatively more intense rainfall events were more efficient in removing the polluted aerosols in the atmosphere. The mean PM_(2.5) scavenging ratio and its standard deviation(SD) were 5.1% ± 25.7%, 38.5% ± 29.0%,and 50.6% ± 21.2% for light, moderate, and heavy rain events, respectively. We further found that the key impact factors on below-cloud PM_(2.5) scavenging ratio for light rain events were rain duration and wind speed rather than raindrop size distribution. However, the impacts of rain duration and wind speed on scavenging ratio were not important for moderate and heavy rain events. To our knowledge, this is the first statistical result about the effects of rain intensity, rain duration, and raindrop size distribution on below-cloud scavenging in China.

关键词： PM2.5 below-cloud scavenging rain intensity impact factors

Thoughts on using scientific system engineering method to develop quantum computer

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The Journal of China Universities of Posts and Telecommunications 2022年第4期29卷 2-8页

作者： Lu Jun luan tian Tang Pengju Zhang Yuntao An Da China Academy of Electronics and Information Technology Beijing 100041China

As the traditional semiconductor complementary metal oxide semiconductor(CMOS)integrated circuit technology gradually approaches the limit of Moore’s Law,quantum computing,as a new system computing technology,with the potential for higher computing speed and lower power consumption,is getting more and more attention from governments and research institutions around the *** instance,the United States(US)government is adopting a bunch of bills to deploy new quantum information processing *** European Union’s“quantum declaration”plans to realize customized quantum computers with more than 100 qubits in the next 10 *** Chinese government also provides strong support for quantum computer research through the project of National Science and Technology Major *** the business field,major companies such as International Business Machines(IBM)Corporation,Intel,Google,Alibaba,Huawei,Baidu,etc.,have joined the“quantum supremacy”competition in order to seize the initiative in the future information *** the rapid development trend of quantum computing,we believe that we should refer to the classical computer industry in the early stage,form an industrial system,and develop the quantum computing *** should also use the scientific system engineering method to carry out the research and development of the quantum computer and establish the ecological environment of the quantum computer industry with the demand as the traction,so as to better serve the development of the national economy.

关键词： quantum quantum computer scientific system engineering industrial system

Optimized Degenerate Bose-Fermi Mixture in Microgravity： DSMC Simulation of Sympathetic Cooling

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Chinese Physics Letters 2014年第4期31卷 41-45页

作者： luan tian JIA Tao CHEN Xu-Zong MA Zhao-Yuan School of Electronics Engineering and Computer Science Peking University Beijing 100871 Shanghai Institute of Optics and Fine Mechanics Chinese Academy of Sciences Shanghai 201800

Applying the direct simulation Monte Carlo （DSMC） method developed for the cold atom system, we explore the possibility of a high-efflciency sympathetic cooling process between 87Rb and 40K without gravitational force in an optical trap. The relation between the pre-cooling of Bosons and the sympathetic cooling efficiency is also studied. We find that the absence of gravitational force is beneficial to the process of sympathetic cooling. fhrthermore, an inefficient pre-cooling process will in fact hamper the creation of Fermi degenerate gases. This suggests the advantages of sympathetic cooling in microgravity.

关键词： Cooling Optimized direct

Toxicity of Fluoranthene and Its Biodegradation by Cyclotella caspia Alga

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Journal of Integrative Plant Biology 2006年第2期48卷 169-180页

作者： Yu Liu tian-Gang luan Ning-Ning Lu Chong-Yu Lan School of Life Sciences State Key Laboratory for Biocontrol Sun Yet-sen （Zhongshan） University Guangzhou 510275 China School of Environmental Sciences and Engineering Sun Yet-sen （Zhongshan） University Guangzhou 510275 China

Fluoranthene Is one of the polynuclear aromatic hydrocarbons with four benzene rings. Because of Its toxicity, mutagenlclty, and carclnogenlclty, fluoranthene Is on the black lists of 129 and 68 priority pollutants established by US Environmental Protection Agency and the People＇s Republic of China, respectively. In recent years, the amount of fluoranthene In the aquatic environment has been Increasing with Increases In anthropogenlc discharge. Based on the biological investigation of tidal water In the Futlan mangrove, Cycioteila ~aspla was selected as the dominant algal species to determine the toxicity of fluoranthene towards C. caspla alga and to Investigate the blodegradatlon of fluoranthene by C. caspla under pure culture. The toxicity experiment showed that the 96-h EC50 value for fluoranthene was 0.2 mg/mL. Four parameters, namely C. caspla algal growth rate, chlorophyll （Chl） a content, cell morphology, and superoxlde dlsmutase （SOD） activity, were chosen as Indices of toxicity and were measured at 6 d （144 h）. The results showed that：（Ⅰ） the toxicity of fluoranthene towards C. caspla alga was obvious; （Ⅱ） C. caspla algal growth rate and Chl a content decreased with Increasing concentrations of fluoranthene; and （Ⅲ） the rate of cell deformation and SOD activity Increased with Increasing concentrations of fluoranthene. The blodegradatlon experiment showed that：（Ⅰ） the rate of physical degradation of fluoranthene was only 5.86%; （Ⅱ） the rate of blodegradatlon of fluoranthene on the 1st and 6th days （l.e. at 24 and 144 h） was approximately 35% and 85%, respectively; and （Ⅲ） the blodegradatlon capability of C. caspla alga towards fluoranthene was high. It is suggested that further Investigations on the toxicity of fluoranthene towards algae, as well as on algal blodegradatlon mechanisms, are of great Importance to use C. caspla as a biological treatment species In an organic wastewater treatment system.

关键词： biodegradation Cyclotella caspia fluoranthene toxicity.

Distribution patterns of octylphenol and nonylphenol in the aquatic system at Mai Po Marshes Nature Reserve,a subtropical estuarine wetland in Hong Kong

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Journal of Environmental Sciences 2007年第6期19卷 657-662页

作者： LI Xiang-li luan tian-gang LIANG Yan WONG Ming-hung LAN Chong-yu Croucher Institute for Environmental Sciences and Department of Biology Hong Kong Baptist UniversityHong Kong China State Key Laboratory of Biocontrol School of life Sciences Sun Yat-Sen （Zhongshan） University Guangzhou 510275 China

Spatial and temporal distribution of octylphenol （OP） and nonylphenol （NP） in Mai Po Marshes, a subtropical estuarine wetland in Hong Kong, were investigated. Surface water samples were collected every month from 11 sites during the period of September- December 2004. Concentrations of OP and NP ranged from 11.3 to 348 ng/L and from 29 to 2591 ng/L, respectively. The high levels of NP and OP were found in November and December than in September and October. The levels of OP and NP have no significant spatial differences except September. Total organic matter in the sediments appeared to be an important factor in controlling the fate of these compounds in the aquatic environment.

关键词： octylphenol nonylphenol endocrine-disrupting chemicals Ramsar Site

Study of atmospheric CO2 and CH4 at Longfengshan WMO/GAW regional station： The variations, trends, influence of local sources/sinks, and transport

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Science China Earth Sciences 2017年第10期60卷 1886-1895页

作者： FANG ShuangXi Pieter P.TANS YAO Bo luan tian WU YanLing YU DaJiang Meteorological Observation Centre (MOC) China Meteorological Administration (CMA) Beijing 100081 China Earth System Research Laboratory (ESRL) Naiional Oceanic and Atmospheric Administration (NOAA) Boulder CO 80305-3337 USA Chinese Academy of Meteorological Seiences (CAMS) China Meteorological Administration (CMA) Beijing 100081 China Longfengshan Regional Background Station China Meteorological Administration (CMA) Harbin 150001 China

Atmospheric CO_2 and CH_4 have been continuously measured since 2009 at Longfengshan WMO/GAW station(LFS) in China. Variations of the mole fractions, influence of long-distance transport, effects of local sources/sinks and the characteristics of synoptic scale variations have been studied based on the records from 2009 to 2013. Both the CO_2 and CH_4 mole fractions display increasing trends in the last five years, with growth rates of 3.1±0.02 ppm yr.1 for CO_2 and 8±0.04 ppb yr.1(standard error, 1-σ)for CH_4. In summer, the regional CO_2 mole fractions are apparently lower than the Marine Boundary Layer reference, with the lowest value of.13.6±0.7 ppm in July, while the CH_4 values are higher than the MBL reference, with the maximum of 139±6 *** 9 to 17(Local time, LT) in summer, the atmospheric CO_2 mole fractions at 10 m a.g.l. are always lower than at 80 m, with a mean difference of.1.1±0.2 ppm, indicating that the flask sampling approach deployed may underestimate the background mole fractions in summer. In winter, anthropogenic emissions dominate the regional CO_2 and CH_4 mole fractions. Cluster analysis of backward trajectories shows that atmospheric CO_2 and CH_4 at LFS are influenced by anthropogenic emissions from the southwest(Changchun and Jilin city) all year. The synoptic scale variations indicate that the northeastern China plain acts as an important source of atmospheric CO_2 and CH_4 in winter.

关键词： Carbon dioxide Methane Observation Backward trajectory Atmospheric transport

Variational Approach to Scattering by Inhomogeneous Layers Above Rough Surfaces

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Communications in Mathematical Research 2014年第1期30卷 71-80页

作者： luan tian MA FU-MING College of Mathematics Jilin University College of Mathematics Beihua University

In this paper, we study, via variational methods, the problem of scattering of time harmonic acoustic waves by unbounded inhomogeneous layers above a sound soft rough surface. We first propose a variational formulation and exploit it as a theoretical tool to prove the well-posedness of this problem when the media is non-absorbing for arbitrary wave number and obtain an estimate about the solution, which exhibit explicitly dependence of bound on the wave number and on the geometry of the domain. Then, based on the non-absorbing results, we show that the variational problem remains uniquely solvable when the layer is absorbing by means of a priori estimate of the solution. Finally, we consider the finite element approximation of the problem and give an error estimate.

关键词： Helmholtz equation rough surface scattering problem

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一种医用防雾护目镜的设计与应用

护理研究 2025年第1期39卷 125-128页

作者：苗建磊赵海燕栾甜郑丹丹徐立丹白雪滨州医学院附属医院山东256600

目的:设计一种医用防雾护目镜,探讨其在重症监护病房中的应用效果。方法:自行设计由镜片、镜框主体、镜带、加热系统和换气系统组成的医用防雾护目镜。将2022年12月20日—25日我院重症监护病房中使用护目镜的80名护士随机分为对照组和... 详细信息

目的:设计一种医用防雾护目镜,探讨其在重症监护病房中的应用效果。方法:自行设计由镜片、镜框主体、镜带、加热系统和换气系统组成的医用防雾护目镜。将2022年12月20日—25日我院重症监护病房中使用护目镜的80名护士随机分为对照组和试验组各40人,对照组使用普通护目镜,试验组使用本研究设计的医用防雾护目镜,比较两组护士憋闷感、护目镜防雾效果和护士满意度。结果:试验组护士憋闷感评分低于对照组,护目镜防雾效果优于对照组,起雾时间晚于对照组,满意度高于对照组,差异均有统计学意义(P<0.05)。结论:采用自行设计的医用防雾护目镜可降低护士使用过程中的憋闷感,减少雾气产生,延长起雾时间,起到良好的防雾效果,提高护士满意度。

关键词：护目镜防雾满意度重症监护室护理