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Showering in Flint, MI: Is there a DBP problem? 被引量:5
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作者 Joshua M.Allen Amy A.Cuthbertson +4 位作者 Hannah K.Liberatore Susana Y.Kimura Anurag Mantha Marc A.Edwards Susan D.Richardson 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2017年第8期271-284,共14页
Lead contamination in the City of Flint, MI has been well documented over the past two years, with lead levels above the EPA Action Level until summer 2016. This resulted from an ill-fated decision to switch from Detr... Lead contamination in the City of Flint, MI has been well documented over the past two years, with lead levels above the EPA Action Level until summer 2016. This resulted from an ill-fated decision to switch from Detroit water(Lake Huron) with corrosion control, to Flint River water without corrosion control. Although lead levels are now closer to normal,reports of skin rashes have sparked questions surrounding tap water in some Flint homes.This study investigated the presence of contaminants, including disinfection by-products(DBPs), in the hot tap water used for showering in the homes of residents in Flint. Extensive quantitative analysis of 61 regulated and priority unregulated DBPs was conducted in Flint hot and cold tap water, along with the analysis of 50 volatile organic compounds and a nontarget comprehensive, broadscreen analysis, to identify a possible source for the reported skin rashes. For comparison, chlorinated hot and cold waters from three other cities were also sampled, including Detroit, which also uses Lake Huron as its source water.Results showed that hot water samples generally contained elevated levels of regulated and priority unregulated DBPs compared to cold water samples, but trihalomethanes were still within regulatory limits. Overall, hot shower water from Flint was similar to waters sampled from the three other cities and did not have unusually high levels of DBPs or other organic chemicals that could be responsible for the skin rashes observed by residents. It is possible that an inorganic chemical or microbial contaminant may be responsible. 展开更多
关键词 Disinfection by-products Disinfection byproducts DBPs Flint Hot water showering Bathing Drinking water
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Modeling of Radon and Its Short-Lived Decay Products during Showering: Dose to Adult Members of the Public
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作者 Rabi Rabi Lhoucine Oufni +3 位作者 Khamiss Cheikh El-Houcine Youssoufi Hamza Badry Youssef Errami 《World Journal of Nuclear Science and Technology》 2021年第2期84-99,共16页
Human exposure to radon inside different parts of the house has become a great concern. In this study, the distribution of radon and its decay inside the shower will be numerically investigated. In fact, the radon con... Human exposure to radon inside different parts of the house has become a great concern. In this study, the distribution of radon and its decay inside the shower will be numerically investigated. In fact, the radon concentration in water is measured through the use of AlphaGUARD. They are used as an input for CFD simulation. The numerical results proved that temperature and humidity have significant impacts on both radon content and distribution. Also, the equilibrium factor variations between radon and its progeny with the temperature and relative humidity were carefully looked at. The equivalent doses due to <sup>218</sup>Po and <sup>214</sup>Po were evaluated in different tissues of the respiratory tract of the members of the public from the inhalation of air inside the shower. The annual effective dose due to radon short lived decay from the inhalation of air inside the shower by the members of the public was also investigated. 展开更多
关键词 RADON Temperature SHOWER Computational Fluid Dynamics (CFD) Effective Dose
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Layered reconstruction framework for longitudinal segmented electromagnetic calorimeter
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作者 Jia-Le Fei Ao Yuan +2 位作者 Ke Wei Liang Sun Ji-Ke Wang 《Nuclear Science and Techniques》 2025年第9期43-58,共16页
In future high-energy physics experiments,the electromagnetic calorimeter(ECAL)should operate with an exceptionally high luminosity.An ECAL featuring a layered readout in the longitudinal direction and precise time-st... In future high-energy physics experiments,the electromagnetic calorimeter(ECAL)should operate with an exceptionally high luminosity.An ECAL featuring a layered readout in the longitudinal direction and precise time-stamped information offers a multidimensional view,thereby enriching our understanding of the showering process of electromagnetic particles in high-luminosity environments.This was used as the baseline design for several new experiments,including the planned upgrades of the current running experiments.Reconstructing and matching multidimensional information across different layers poses new challenges for the effective utilization of layered data.This study introduced a novel layered reconstruction framework for ECAL with a layered readout information structure and developed a corresponding layered clustering algorithm.This expands the concept of clusters from a plane to multiple layers.Additionally,this study presents the corresponding layered cluster correction methods,investigates the transverse shower profile utilized for overlapping cluster splitting,and develops a layered mergedπ^(0)reconstruction algorithm based on this framework.By incorporating energy and time information into 3-dimensions,this framework provides a suitable software platform for preliminary research on longitudinally segmented ECAL and new perspectives in physics analyses.Furthermore,using the PicoCal in LHCb Upgrade II as a concrete example,the performance of the framework was preliminarily evaluated using single photons andπ^(0)particles from the neutral B^(0)meson decay B^(0)→π^(+)π^(-)π^(0)as benchmarks.The results demonstrate that,compared to the unlayered framework,utilizing this framework for longitudinally segmented ECAL significantly enhances the position resolution and the ability to split overlapping clusters,thereby improving the reconstruction resolution and efficiency for photons andπ^(0)s. 展开更多
关键词 Electromagnetic calorimeter Layered reconstruction Transverse shower profile Mergedπ^(0)reconstruction
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NSRL电子储存环束流损失过程的Monte-Carlo计算 被引量:1
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作者 李裕熊 邵贝贝 +1 位作者 田雨润 崔永刚 《辐射防护》 CAS CSCD 北大核心 2001年第4期238-241,共4页
高能电子和物质相互作用是一个级联簇射 (shower)物理过程。 NSRL电子储存环 (HLS)束流损失监测系统利用这一原理 ,通过探测束流损失电子在储存环真空室外表面产生的 shower电子 ,给出束流损失的有关信息。本文利用 Monte- Carlo方法 ,... 高能电子和物质相互作用是一个级联簇射 (shower)物理过程。 NSRL电子储存环 (HLS)束流损失监测系统利用这一原理 ,通过探测束流损失电子在储存环真空室外表面产生的 shower电子 ,给出束流损失的有关信息。本文利用 Monte- Carlo方法 ,采用 EGS4软件包 ,对束流损失电子与真空室壁相互作用的过程进行模拟 ,给出了真空室外表面 shower电子的分布特点 :(1) shower电子在真空室外表面是前冲性很强的粒子 ;(2 )在垂直方向的分布是比较窄的对称分布 ,对束流损失探测器的安装有一定的要求 ;(3)打在真空室内侧壁上的电子及其产生的 shower电子有机会反射到外侧壁 ,并进一步发生 shower过程 ,但其影响会低两个量级以上 ;(4) shower电子在真空室外表面上的分布 。 展开更多
关键词 MONTE-CARLO方法 GS4 束流损失 加速器 Shower电子分布 NSRL电子储存环
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WZ Sagittae, SN 1054, and SN 1006 Space Weather--Global Warming 被引量:1
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作者 W. P. Sokeland 《Journal of Earth Science and Engineering》 2017年第4期194-216,共23页
The proof of three different nova or supernova debris streams impacting the planet and causing global warming is shown by studying the effects, locations, and timings for specific thermal and destructive events in the... The proof of three different nova or supernova debris streams impacting the planet and causing global warming is shown by studying the effects, locations, and timings for specific thermal and destructive events in the northern and southern hemisphere. Global warming is not manmade and reducing fossil fuel emissions is not the solution to protect the populations of different countries from catastrophic events due to increased thermal energy storage for the planet, The burning of atoms of incoming debris streams from exploding stars produces energy and greenhouse gases that cause the average temperature of our planet to increase. India is the current hotspot due to the location of the deflected western terminus of SN 1006. Hotspots occur that are not as obvious as the India case, but melting sea ice exposes the debris streams' hotspot activities. The incoming momentum of a debris stream can displace a large amount of polar atmosphere upon impact causing unusually extreme freezing conditions at lower latitudes like the year without a summer of 1812. The third tine of Satan's pitchfork known as high sea surface temperatures indicating El Nino is located directly between the north and south hotspots and occurs during initial high particle densities related to impact of the debris stream. 展开更多
关键词 WARMING global SUPERNOVA NOVA TORNADO ice METEOR shower.
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The Third Peak of the 1998 Leonid Meteor Shower 被引量:2
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作者 Yue-HuaMa You-WenHe 《Chinese Journal of Astronomy and Astrophysics》 CSCD 北大核心 2001年第3期271-274,共4页
The Leonid meteor shower in November 1998 was observed widely by astronomers. The first peak, rich in bright meteors, appeared about 16 hours before the predicted maximum of the main shower. The main shower was also o... The Leonid meteor shower in November 1998 was observed widely by astronomers. The first peak, rich in bright meteors, appeared about 16 hours before the predicted maximum of the main shower. The main shower was also observed by both optical and radio methods during 19:00-21:00 UT on Nov. 17, and the radio peak was over 2500h-1. About 18 hours after the main shower, an abnormal phenomenon in the ionosphere was detected by two separate ionosphere observing stations. And the very high abnormal phenomenon maintained over one hour. The phenomenon showed that the ionosphere was injected with a large amount of small dust particles that could not be observed in optical and radio. The Observational results show that the Leonid meteor shower in 1998 had three peaks. 展开更多
关键词 Meteors: Leonid meteor shower
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Risk Factors for Conjunctival Microorganism Colonization in Adults Undergoing Intraocular Surgery
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作者 Orly Halachmi-Eyal Yoram Keness +2 位作者 Yaron Lang Daniel Briscoe Dan Miron 《Open Journal of Ophthalmology》 2012年第2期26-30,共5页
Purpose: To assess prevalence of and risk factors for conjunctival colonization and types of organisms among adults undergoing elective intraocular surgery. Setting: Ha’Emek Medical Center, Afula, Israel. Methods: A ... Purpose: To assess prevalence of and risk factors for conjunctival colonization and types of organisms among adults undergoing elective intraocular surgery. Setting: Ha’Emek Medical Center, Afula, Israel. Methods: A prospective study conducted in the Ophthalmology Department at Ha’Emek Medical Center, Afula, Israel between May 1, 2006 and August 31, 2007. Included were adults undergoing elective intraocular surgeries. Conjunctival cultures were obtained from the lower fornix, prior to application of prophylactic decolonization treatment and were processed using routine microbiological techniques. Demographic, socioeconomic and medical data of our patient cohort were obtained from all participants. Results: Cultures were obtained from 501 patients. (Mean age 69.7 ± 12.0 years) of whom 52.1% were females. In 208 patients (40.5%) bacteria grew in conjunctival cultures, one type in 175 (34.9%) one, and two types in 28 (5.6%). In none fungi were isolated. Coagulase negative Staphylococcus was the most frequent bacteria isolated. By multivariate analysis, significant risk factors for conjunctival bacterial colonization were spring/summer seasons (OR 1.64, CI 1.15 - 2.36, P < 0.007), and showering on the day of the operation (OR 1.73, CI 1.11 - 2.69, P < 0.01). Conclusions: In addition to previously known risk factors for conjunctival microorganism colonization, the present study found showering on the morning of the operation, possibly related to bacteria on towels or in the eyelids and lashes, and time of year (spring/summer) perhaps resulting from higher temperature and humidity related to the presence of conjunctival bacteria to be significant in adults undergoing intraocular surgery. 展开更多
关键词 CONJUNCTIVA Culture Bacteria COAGULASE Negative STAPHYLOCOCCUS CATARACT SHOWER Climate
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Suggesting a Very Simple Experiment Designed to Detect Tachyons
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作者 Jerzy K. Kowalczyński 《Journal of Modern Physics》 2011年第2期92-96,共5页
Production of tachyons in, among other things, air showers would be in accordance with predictions of general relativity. Some such tachyons would travel with a precisely determined speed, almost equal to 5c/3 relativ... Production of tachyons in, among other things, air showers would be in accordance with predictions of general relativity. Some such tachyons would travel with a precisely determined speed, almost equal to 5c/3 relative to the earth, and would be registered high above the region of creation of air showers, e.g. on board of a satellite. A very simple experiment designed to detect these tachyons is outlined here. Brief justification to search for tachyons is also given. 展开更多
关键词 TACHYON HIGH-ENERGY Collision Air SHOWER TIME-OF-FLIGHT Experiment Satellite
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Investigation into the Effects of SORxSOAP in the Job-Related Performance of Deli Meat Slicers over a One-Month Period
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作者 Daniel Staats Gustave Gallinot 《Occupational Diseases and Environmental Medicine》 2022年第3期196-205,共10页
Instrument-assisted soft tissue mobilization is well researched and widely accepted to improve circulation, decrease pain, improve function, increase strength, and promote overall soft tissue health. However, the admi... Instrument-assisted soft tissue mobilization is well researched and widely accepted to improve circulation, decrease pain, improve function, increase strength, and promote overall soft tissue health. However, the administration of this intervention, in most cases, is limited to the brief amounts of time we spend mobilizing our soft tissue. SORxSOAP offers a pragmatic strategy by which one may mobilize their soft tissue while simultaneously showering or washing a specific part of their body. The purpose of this study is to demonstrate the effects SORxSOAP has on functional measures of upper extremity activity in the slicing hands of employees at a corporate deli franchise over the course of a one-month period. 31 employees of a corporate deli franchise were asked to participate in a study involving the use of SORxSOAP. The subjects were assigned to experimental and control groups rough random sampling. Twenty-one subjects in the experimental group were given a one month’s supply of SORxSOAP to use on a regular basis while showering. Ten subjects in the control group were not exposed to any independent variable. The subjects from both groups completed a questionnaire that asked the subjects to rate the level of ease at which specific job-related activities were for them to perform. Hand-strength/grip and range of motion measurements were also taken utilizing a handheld dynamometer and goniometer respectively by one evaluator both before and after a one-month duration of the experimental group’s exposure to SORxSOAP. Independent t-tests were performed to test the difference between pre and post-test values for the control and experimental groups. It was found that SORxSOAP significantly improves wrist flexion range of motion, results in significantly greater improvements in hand-grip strength compared to control, and significantly improves wrist extension range of motion over a one-month period. Improvements in the ease of job-related activities also appear to be correlated to the use of SORxSOAP for items #1, 2, 3, 4, 5, 6, 7, and 9. Significant differences were also found between the slicing and non-slicing hands for pre-test wrist extension range of motion measurements, indicating the presence of possible over-use injury in occupations and activities placing excessive demand on certain body regions. This provides isolated evidence that supports the notion that SORxSOAP could be a viable option for preventing the steady decline of wrist extension range of motion and actually promoting and maintaining soft tissue and overall joint health, making it clear how further investigation into the effects of SORxSOAP can not only improve joint and soft tissue health, but prevent the emergence of joint and soft tissue impairment entirely. Clinical Bottom Line: The use of SORxSOAP has the potential to significantly improve muscle and soft tissue performance and function over a period of one month. 展开更多
关键词 SORxSOAP Soresoap Soap Muscle Relief Health Hygiene WELLNESS Injury Prevention Overuse Injury Soft Tissue MASSAGE SHOWER Bath and Body
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tokyo boy cam Take a shower~出门之前~ 甲斐翔真
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作者 Eiki Mori Naoko Yamamoto 《美眉》 2019年第6期137-137,136,共2页
2015年开始演员活动,并迅速试镜成功《假面骑士EX-AID》。随后,他出演小岩井生乳酸奶的CM《妈妈变了》篇,引发'那个帅气的儿子是谁'的话题讨论,职业发展顺利的甲斐翔真。童颜的他,却有着185cm的身高和踢球锻炼出来的结实身材,... 2015年开始演员活动,并迅速试镜成功《假面骑士EX-AID》。随后,他出演小岩井生乳酸奶的CM《妈妈变了》篇,引发'那个帅气的儿子是谁'的话题讨论,职业发展顺利的甲斐翔真。童颜的他,却有着185cm的身高和踢球锻炼出来的结实身材,给人反差萌的印象。未来可期的21岁的他,在森荣喜的镜头下书写——。 展开更多
关键词 假面骑士 守门员 TAKE a SHOWER TOKYO BOY CAM
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Relationship and Variability of Atmospheric Precipitation Characteristics in the North-West of Ukraine
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作者 Svetlana Vasilievna Budnik 《Journal of Atmospheric Science Research》 2023年第3期30-40,共11页
The paper deals with the issues of differentiation of atmospheric precipitation into gradations according to their characteristics and established meteorological practices.The division of atmospheric precipitation int... The paper deals with the issues of differentiation of atmospheric precipitation into gradations according to their characteristics and established meteorological practices.The division of atmospheric precipitation into gradations allows one to have an idea of the possible consequences of their fallout on life in the area.The dependence of the average intensity of precipitation on their duration for the entire series of observations is not described by a power-law dependence with a sufficient degree of reliability,and when differentiating into gradations according to the amount of precipitation(<2.5 mm,2.5-10 mm,≥10 mm),the dependences are obtained with a high degree of correlation.The scatter of points can be explained by the presence of intermediate categories of precipitation,which does not take into account the accepted division of the data.Thus,for large values of the amount of precipitation,the existence of a sepa­rate curve is possible,since the existing classifications of precipitation imply the division of heavy showers into sepa­rate gradations.Differentiation of rains by their duration shows a stronger stratification of the field of points for shorter rains(up to 60 minutes).This stratification of the field of points is successfully differentiated into shorter segments of 20,30 minutes.Associated with the greater heterogeneity of shorter precipitation,it can be both rains of low intensi­ty and heavy downpours of short duration.The probability of the position of the maximum intensity of precipitation during rain has more significant differences for precipitation less than 2.5 mm(the curves are more curved).For rains with a precipitation amount of 2.5 mm or more,the probability curves approach straight lines,which is associated with greater heterogeneity of precipitation less than 2.5 mm. 展开更多
关键词 Precipitation GRADATION INTENSITY DURATION SHOWER
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Study on Remediation Technology of PAH-contaminated Soil
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作者 MAWenqiang WANGXiumei +1 位作者 ZHANGJiwu WANGKuan 《外文科技期刊数据库(文摘版)自然科学》 2022年第9期088-092,共5页
In view of the reality of PAH soil repair difficult, through the study of different oxidants and new surfactant, realize the detergent repair technology in the treatment of PAH contaminated soil application. At the sa... In view of the reality of PAH soil repair difficult, through the study of different oxidants and new surfactant, realize the detergent repair technology in the treatment of PAH contaminated soil application. At the same time, with potassium permanganate, sodium persulfate, hydrogen peroxide detergent as detergent experiment, compare the different detergent effect. The experimental results show that the removal rate of oxidant potassium permanganate can reach 95.3% and 80.6% in PAH-contaminated soil, and the removal effect of surfactant detergent and OP-10 is also very obvious. 展开更多
关键词 PAHS SHOWER soil remediation SURFACTANT
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Shower It,In Your Bathroom
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作者 Tom Xue 《China Textile》 2008年第11期22-24,共3页
Technology always brings us surprise and change life everyday. What you said,when you do your wool suits domestic cleaning with warm water at about 40° C,at your bathroom?Crazy?Easy-care?Wow,it's all about Me... Technology always brings us surprise and change life everyday. What you said,when you do your wool suits domestic cleaning with warm water at about 40° C,at your bathroom?Crazy?Easy-care?Wow,it's all about MerinoFreshTM! 展开更多
关键词 Shower It In Your Bathroom
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Editorial
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作者 Ruizhi Yang Zhen Cao 《Science China(Physics,Mechanics & Astronomy)》 2025年第7期1-1,共1页
The Galactic plane serves as a natural laboratory for exploring high-energy astrophysical processes,where cosmic rays are accelerated,propagate,and interact with other components in the interstellar medium(ISM).With i... The Galactic plane serves as a natural laboratory for exploring high-energy astrophysical processes,where cosmic rays are accelerated,propagate,and interact with other components in the interstellar medium(ISM).With its unprecedented sensitivity and extensive energy coverage,the Large High Altitude Air Shower Observatory(LHAASO) has opened a new era of Galactic gamma-ray astronomy,especially in the ultra-high-energy(UHE) domain.The recent “Galactic Mini Survey” conducted by LHAASO provides an unprecedented view of UHE gamma-ray sources within the Milky Way. 展开更多
关键词 interstellar medium ultra high energy gamma ray sources cosmic rays galactic plane large high altitude air shower observatory gamma ray astronomy
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Observation of theγ-ray emission from W43 with LHAASO
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作者 Zhen Cao F.A.haronian +296 位作者 Axikegu Y.X.Bai Y.W.Bao D.Bastieri X.J.Bi Y.J.Bi W.Bian A.V.Bukevich Q.Cao W.Y.Cao Zhe Cao J.Chang J.F.Chang A.M.Chen E.S.Chen H.X.Chen Liang Chen Lin Chen Long Chen M.J.Chen M.L.Chen Q.H.Chen S.Chen S.H.Chen S.Z.Chen T.L.Chen Y.Chen N.Cheng Y.D.Cheng M.C.Chu M.Y.Cui S.W.Cui X.H.Cui Y.D.Cui B.Z.Dai H.L.Dai Z.G.Dai Danzengluobu X.Q.Dong K.K.Duan J.H.Fan Y.Z.Fan J.Fang J.H.Fang K.Fang C.F.Feng H.Feng L.Feng S.H.Feng X.T.Feng Y.Feng Y.L.Feng S.Gabici B.Gao C.D.Gao Q.Gao W.Gao W.K.Gao M.M.Ge T.T.Ge L.S.Geng G.Giacinti G.H.Gong Q.B.Gou M.H.Gu F.L.Guo J.Guo X.L.Guo Y.Q.Guo Y.Y.Guo Y.A.Han O.A.Hannuksela M.Hasan H.H.He H.N.He J.Y.He Y.He Y.K.Hor B.W.Hou C.Hou X.Hou H.B.Hu Q.Hu S.C.Hu C.Huang D.H.Huang T.Q.Huang W.J.Huang X.T.Huang X.Y.Huang Y.Huang Y.Y.Huang X.L.Ji H.Y.Jia K.Jia H.B.Jiang K.Jiang X.W.Jiang Z.J.Jiang M.Jin M.M.Kang I.Karpikov D.K.hangulyan D.Kuleshov K.Kurinov B.B.Li C.M.Li Cheng Li Cong Li D.Li F.Li H.B.Li H.C.Li Jian Li Jie Li K.Li S.D.Li W.L.Li W.L.Li X.R.Li Xin Li Y.Z.Li Zhe Li Zhuo Li E.W.Liang Y.F.Liang S.J.Lin B.Liu C.Liu D.Liu D.B.Liu H.Liu H.D.Liu J.Liu J.L.Liu M.Y.Liu R.Y.Liu S.M.Liu W.Liu Y.Liu Y.N.Liu Q.Luo Y.Luo H.K.Lv B.Q.Ma L.L.Ma X.H.Ma J.R.Mao Z.Min W.Mitthumsiri H.J.Mu Y.C.Nan A.Neronov K.C.Y.Ng L.J.Ou P.Pattarakijwanich Z.Y.Pei J.C.Qi M.Y.Qi B.Q.Qiao J.J.Qin A.Raza D.Ruffolo A.Saiz´ M.Saeed D.Semikoz L.Shao O.Shchegolev X.D.Sheng F.W.Shu H.C.Song Yu V.Stenkin V.Stepanov Y.Su D.X.Sun Q.N.Sun X.N.Sun Z.B.Sun J.Takata P.H.T.Tam Q.W.Tang R.Tang Z.B.Tang W.W.Tian L.H.Wan C.Wang C.B.Wang G.W.Wang H.G.Wang H.H.Wang J.C.Wang Kai Wang Kai Wang L.P.Wang L.Y.Wang P.H.Wang R.Wang W.Wang X.G.Wang X.Y.Wang Y.Wang Y.D.Wang Y.J.Wang Z.H.Wang Z.X.Wang Zhen Wang Zheng Wang D.M.Wei J.J.Wei Y.J.Wei T.Wen C.Y.Wu H.R.Wu Q.W.Wu S.Wu X.F.Wu Y.S.Wu S.Q.Xi J.Xia G.M.Xiang D.X.Xiao G.Xiao Y.L.Xin Y.Xing D.R.Xiong Z.Xiong D.L.Xu R.F.Xu R.X.Xu W.L.Xu L.Xue D.H.Yan J.Z.Yan T.Yan C.W.Yang C.Y.Yang F.Yang F.F.Yang L.L.Yang M.J.Yang R.Z.Yang W.X.Yang Y.H.Yao Z.G.Yao L.Q.Yin N.Yin X.H.You Z.Y.You Y.H.Yu Q.Yuan H.Yue H.D.Zeng T.X.Zeng W.Zeng M.Zha B.B.Zhang F.Zhang H.Zhang H.M.Zhang H.Y.Zhang J.L.Zhang Li Zhang P.F.Zhang P.P.Zhang R.Zhang S.B.Zhang S.R.Zhang S.S.Zhang X.Zhang X.P.Zhang Y.F.Zhang Yi Zhang Yong Zhang B.Zhao J.Zhao L.Zhao L.Z.Zhao S.P.Zhao X.H.Zhao F.Zheng W.J.Zhong B.Zhou H.Zhou J.N.Zhou M.Zhou P.Zhou R.Zhou X.X.Zhou X.X.Zhou B.Y.Zhu C.G.Zhu F.R.Zhu H.Zhu K.J.Zhu Y.C.Zou X.Zuo The LHAASO Collaboration 《Science China(Physics,Mechanics & Astronomy)》 2025年第7期2-12,共11页
In this paper,we report the detection of the very-high-energy(VHE,100 GeV<E<100 TeV)and ultra-high-energy(UHE,E>100 TeV)y-ray emissions from the direction of the young star-forming region W43,observed by the ... In this paper,we report the detection of the very-high-energy(VHE,100 GeV<E<100 TeV)and ultra-high-energy(UHE,E>100 TeV)y-ray emissions from the direction of the young star-forming region W43,observed by the Large High Altitude Air Shower Observation(LHAASO).The extendedγ-ray source was detected with a significance of~16σby KM2A and~17σby WCDA,respectively.The angular extension of this y-ray source is about 0.5 degrees,corresponding to a physical size of about 50pc.We discuss the origin of theγ-ray emission and possible cosmic ray acceleration in the W43 region using multi-wavelength data.Our findings suggest that W43 is likely another young star cluster capable of accelerating cosmic rays(CRs)to at least several hundred TeV. 展开更多
关键词 large high altitude air shower observation lhaaso gamma ray emission cosmic ray acceleration multi wavelength data ultra high energy gamma rays W star forming region very high energy gamma rays
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Monte Carlo方法在核辐射医学中的应用 被引量:1
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作者 许淑艳 梁勇 +2 位作者 丰树强 刘保杰 郑玉来 《清华大学学报(自然科学版)》 EI CAS CSCD 北大核心 2007年第z1期907-909,共3页
在放射性治疗(外照射或内照射)疑难病症(如癌症)及重症病过程中,病体所受剂量及其分布是治疗过程中必须考虑的问题。当射线进入人体后各部分受到的剂量必须要进行理论计算。射线在人体内的反应机制是光子和电子偶合输运过程,非常复杂,... 在放射性治疗(外照射或内照射)疑难病症(如癌症)及重症病过程中,病体所受剂量及其分布是治疗过程中必须考虑的问题。当射线进入人体后各部分受到的剂量必须要进行理论计算。射线在人体内的反应机制是光子和电子偶合输运过程,非常复杂,一般数值方法难于求解。Monte Carlo方法是解决本类问题十分有效的方法。该文将Monte Carlo方法应用到核辐射医学中,叙述了两种体内剂量场分布的Monte Carlo计算方法:沉积能量法和通量转换法。为了提高计算效率,给出了几种实用的技巧。最后,介绍了一个应用实例。 展开更多
关键词 MONTE CARLO方法 核辐射医学 EGS4(electron GAMMA shower)
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^(60)Co远程治疗机剂量场分布的Monte Carlo计算
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作者 丰树强 刘保杰 程金生 《清华大学学报(自然科学版)》 EI CAS CSCD 北大核心 2007年第z1期914-916,共3页
基于60Co放射源的远程治疗机是常用的放疗设备。对治疗机的靶区做精确的剂量计算有助于确保放疗质量。传统的半经验解析方法在计算上适用范围小,几何模型稍显复杂之后就难以得到理想的结果。本文使用Monte Carlo方法,借助于EG S4软件包... 基于60Co放射源的远程治疗机是常用的放疗设备。对治疗机的靶区做精确的剂量计算有助于确保放疗质量。传统的半经验解析方法在计算上适用范围小,几何模型稍显复杂之后就难以得到理想的结果。本文使用Monte Carlo方法,借助于EG S4软件包计算了不同射野下60Co远程治疗机在水膜体中的三维剂量场分布。为了提高抽样效率,对源粒子的运动方向采用了解析方法确定。将得到的计算结果与用RTS-200S自动扫描水箱测量的离轴剂量和中心轴深度剂量比较,二者符合得很好。 展开更多
关键词 MONTE CARLO方法 剂量分布 60Co EGS(electron GAMMA shower) 放射治疗 远程治疗机
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A future project at tibet:the large high altitude air shower observatory(LHAASO) 被引量:32
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作者 曹臻 《Chinese Physics C》 SCIE CAS CSCD 2010年第2期249-252,共4页
Gamma ray source detection above 30 TeV is an encouraging approach for finding galactic cosmic ray sources. All sky survey for gamma ray sources using wide field of view detector is essential for population accumulati... Gamma ray source detection above 30 TeV is an encouraging approach for finding galactic cosmic ray sources. All sky survey for gamma ray sources using wide field of view detector is essential for population accumulation for various types of sources above 100 GeV. In order to target those goals, a large air shower particle detector array of 1 km^2 (the LHAASO project) at 4300 m a.s.l, is proposed, By adding two MagicⅡ- type telescopes in the array as proposed, LHAASO will be enhanced in source morphologic investigation power. The proposed array will be utilized also for energy spectrum measurement for individual cosmic ray species above 30 TeV. By re-configuring the wide field of view telescopes into fluorescence light detector array, the aperture of the detector array can be enlarged to cover an energy region above 100 PeV where the second knee is located. Cosmic ray spectrum and composition will be measured in order to transfer an energy scale to ultra high energy cosmic ray experiments. 展开更多
关键词 air shower detector array gamma ray astronomy cosmic ray
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Observation of the Crab Nebula with LHAASO-KM2A−a performance study 被引量:12
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作者 F.Aharonian Q.An +245 位作者 Axikegu L.X.Bai Y.X.Bai Y.W.Bao D.Bastieri X.J.Bi Y.J.Bi H.Cai J.T.Cai Z.Cao J.Chang J.F.Chang X.C.Chang B.M.Chen J.Chen L.Chen M.J.Chen M.L.Chen Q.H.Chen S.H.Chen S.Z.Chen T.L.Chen X.L.Chen Y.Chen N.Cheng Y.D.Cheng S.W.Cui X.H.Cui Y.D.Cui B.Z.Dai H.L.Dai Z.G.Dai D.della Volpe B.D'Ettorre Piazzoli X.J.Dong J.H.Fan Y.Z.Fan Z.X.Fan J.Fang K.Fang C.F.Feng L.Feng S.H.Feng Y.L.Feng B.Gao C.D.Gao Q.Gao W.Gao M.M.Ge L.S.Geng G.H.Gong Q.B.Gou M.H.Gu J.G.Guo X.L.Guo Y.Q.Guo Y.Y.Guo Y.A.Han H.H.He H.N.He J.C.He S.L.He X.B.He Y.He M.Heller Y.K.Hor C.Hou X.Hou H.B.Hu S.Hu S.C.Hu X.J.Hu D.H.Huang Q.L.Huang W.H.Huang X.T.Huang Z.C.Huang F.Ji X.L.Ji H.Y.Jia K.Jiang Z.J.Jiang C.Jin D.Kuleshov K.Levochkin B.B.Li C.Li F.Li H.B.Li H.C.Li H.Y.Li J.Li K.Li W.L.Li X.Li X.R.Li Y.Li Y.Z.Li Z.Li E.W.Liang Y.F.Liang S.J.Lin B.Liu C.Liu D.Liu H.Liu H.D.Liu J.Liu J.L.Liu J.S.Liu J.Y.Liu M.Y.Liu R.Y.Liu S.M.Liu W.Liu Y.N.Liu Z.X.Liu W.J.Long R.Lu H.K.Lv B.Q.Ma L.L.Ma X.H.Ma J.R.Mao A.Masood W.Mitthumsiri T.Montaruli Y.C.Nan B.Y.Pang P.Pattarakijwanich Z.Y.Pei M.Y.Qi D.Ruffolo V.Rulev A.Sáiz L.Shao O.Shchegolev X.D.Sheng J.R.Shi H.C.Song Yu.V.Stenkin V.Stepanov Q.N.Sun X.N.Sun Z.B.Sun P.H.T.Tam Z.B.Tang W.W.Tian B.D.Wang C.Wang H.Wang H.G.Wang J.C.Wang J.S.Wang L.P.Wang L.Y.Wang R.N.Wang W.Wang X.G.Wang X.J.Wang X.Y.Wang Y.D.Wang Y.J.Wang Y.P.Wang Z.Wang Z.H.Wang Z.X.Wang D.M.Wei J.J.Wei Y.J.Wei T.Wen C.Y.Wu H.R.Wu S.Wu W.X.Wu X.F.Wu S.Q.Xi J.Xia J.J.Xia G.M.Xiang G.Xiao H.B.Xiao G.G.Xin Y.L.Xin Y.Xing D.L.Xu R.X.Xu L.Xue D.H.Yan C.W.Yang F.F.Yang J.Y.Yang L.L.Yang M.J.Yang R.Z.Yang S.B.Yang Y.H.Yao Z.G.Yao Y.M.Ye L.Q.Yin N.Yin X.H.You Z.Y.You Y.H.Yu Q.Yuan H.D.Zeng T.X.Zeng W.Zeng Z.K.Zeng M.Zha X.X.Zhai B.B.Zhang H.M.Zhang H.Y.Zhang J.L.Zhang J.W.Zhang L.Zhang L.X.Zhang P.F.Zhang P.P.Zhang R.Zhang S.R.Zhang S.S.Zhang X.Zhang X.P.Zhang Y.Zhang Y.F.Zhang Y.L.Zhang B.Zhao J.Zhao L.Zhao L.Z.Zhao S.P.Zhao F.Zheng Y.Zheng B.Zhou H.Zhou J.N.Zhou P.Zhou R.Zhou X.X.Zhou C.G.Zhu F.R.Zhu H.Zhu K.J.Zhu X.Zuo 《Chinese Physics C》 SCIE CAS CSCD 2021年第2期518-530,共13页
A sub-array of the Large High Altitude Air Shower Observatory(LHAASO),KM2A is mainly designed to observe a large fraction of the northern sky to hunt for γ-ray sources at energies above 10 TeV.Even though the detecto... A sub-array of the Large High Altitude Air Shower Observatory(LHAASO),KM2A is mainly designed to observe a large fraction of the northern sky to hunt for γ-ray sources at energies above 10 TeV.Even though the detector construction is still underway,half of the KM2A array has been operating stably since the end of 2019.In this paper,we present the KM2A data analysis pipeline and the first observation of the Crab Nebula,a standard candle in very high energy γ-ray astronomy.We detect γ-ray signals from the Crab Nebula in both energy ranges of 10-100 TeV and>100 TeV with high significance,by analyzing the KM2A data of 136 live days between December 2019 and May 2020.With the observations,we test the detector performance,including angular resolution,pointing accuracy and cosmic-ray background rejection power.The energy spectrum of the Crab Nebula in the energy range 10-250 TeV fits well with a single power-law function dN/dE=(1.13±0.05stat±0.08sys)×10^(-14).(E/20 TeV)-309±0.06stat±0.02syscm^(-2) s^(-1) TeV^(-1).It is consistent with previous measurements by other experiments.This opens a new window of γ-ray astronomy above 0.1 PeV through which new ultrahigh-energy γ-ray phenomena,such as cosmic PeVatrons,might be discovered. 展开更多
关键词 Γ-RAY Crab Nebula extensive air showers cosmic rays
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Design of the LHAASO detectors 被引量:15
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作者 Huihai He For the LHAASO Collaboration 《Radiation Detection Technology and Methods》 2018年第1期49-56,共8页
Introduction The Large High Altitude Air Shower Observatory plans to build a hybrid extensive air shower array with an area of about 1 km^(2) at an altitude of 4,410 m a.s.l.in Sichuan province,China,to explore the or... Introduction The Large High Altitude Air Shower Observatory plans to build a hybrid extensive air shower array with an area of about 1 km^(2) at an altitude of 4,410 m a.s.l.in Sichuan province,China,to explore the origin of high-energy cosmic rays.KM2A LHAASO-KM2A will detect gamma ray sources with a sensitivity of about 1%Crab Unit at 100 TeV.It covers an area of 1 km^(2) with a total of 5195 scintillation detectors.Its angular resolution reaches about 0.3 degrees,and the energy resolution is better than 25%.With the help of 1171 muon detectors,cosmic nuclei background will be rejected to a level of 10-4 at 50 TeV.The design and performances of the scintillation detectors and muon detectors are described in detail.WCDA LHAASO-WCDA focuses on surveying the northern sky for steady and transient sources from 100 GeV to 20 TeV,with a very high background rejection power and a good angular resolution.The WCDA consists of three water ponds with a total area of 78,000 m^(2),and the effective water depth is 4 m.Each water pond is divided into 5m×5m cells partitioned by black plastic curtains to prevent penetration of the light from neighboring cells.An 8-inch PMT sits at the bottom center of each cell,looking upward to collect Cherenkov light generated by shower secondary particles in water.WFCTA LHAASO-WFCTA is composed of 12 wide-field-of-view Cherenkov/fluorescence telescopes.Each telescope consists of a spherical light collector of about 4.7 m^(2) and focal plane camera of 32×32 pixels with a pixel size of 0.5 degree.LHAASO prototype arrays A prototype array about 1%of LHAASO has been constructed at Yangbajing Cosmic Ray Observatory and has been in operation for more than 2 years.Its performance fully meets the design requirements.Conclusion The LHAASO detectors are designed to fulfill the physical goals in gamma ray astronomy and cosmic ray physics.One-fourth of LHAASO will be constructed and put into operation to produce physical data by the end of 2018.The whole array will be finished in the beginning of 2021. 展开更多
关键词 Origin of cosmic rays Gamma ray astronomy Extensive air shower
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