期刊文献+
共找到326篇文章
< 1 2 17 >
每页显示 20 50 100
Alcohol drinking rates of male between 7th and 11th graders in Japan decreased gradually based on nationwide repeated cross-sectional surveys from 1996 to 2008 被引量:1
1
作者 Hideyuki Kanda Yoneatsu Osaki +4 位作者 Yoshitaka Kaneita Osamu Itani Maki Ikeda Takashi Ohida Susumu Higuchi 《Health》 2013年第6期12-17,共6页
Early drinking is considered to result in making tolerant of alcohol consumption and a higher prevalence of alcohol related disorders in the later. We focused generational impacts on drinking rate among high school st... Early drinking is considered to result in making tolerant of alcohol consumption and a higher prevalence of alcohol related disorders in the later. We focused generational impacts on drinking rate among high school students based on multiple nationwide data. The surveys were nationwide, cross-sectional random sampling surveys given every 4 years from the Japanese Youth Tobacco and Alcohol Surveys, 1996 to 2008. Participants were male 53,925 high school students from 7th grade to 11th grade. We divided to the three follow-up groups every 4 years from 1996 to 2004 for male junior high school students in 7th grades and the end periods were 4 years later in 11th grades. Outcome measures in this study were life time drinking, current drinking within 30 days and weekly drinking. All drinking rates decreased each at 7th and at 11th grade. The increments in these drinking rates from 7th grade to 11th grade in males decreased gradually in recent follow-up groups. Generational impacts should be considered by using follow-up groups to study drinking behaviors among students. 展开更多
关键词 drinking rates Repeated CROSS-SECTIONAL Study National Wide Survey JAPAN
下载PDF
Individual Differences in Blood Alcohol Concentrations after Moderate Drinking Are Mainly Regulated by Gastric Emptying Rate Together with Ethanol Distribution Volume 被引量:1
2
作者 Shunji Oshima Takeshi Haseba +4 位作者 Chiaki Masuda Ema Kakimi Manabu Sami Tomomasa Kanda Youkichi Ohno 《Food and Nutrition Sciences》 2012年第6期732-737,共6页
Blood alcohol concentration (BAC) differs greatly among individuals, even when people of the same sex and age drink alcohol under the same drinking conditions. In this study, we investigated the main factors involved ... Blood alcohol concentration (BAC) differs greatly among individuals, even when people of the same sex and age drink alcohol under the same drinking conditions. In this study, we investigated the main factors involved in the internal reg-ulation of individual differences in BAC, focusing on the alcohol dehydrogenase 1B (ADH1B) genotype, blood acetal-dehyde concentration (BAcH), amount of habitual alcohol consumption, pharmacokinetic parameters of BAC, distribution volume of ethanol (Vd), and gastric emptying rate (GER) under the same drinking conditions. Twenty healthy Japanese males aged between 40 and 59 years old and having the aldehyde dehydrogenase 2 (ALDH2) genotype of ALDH 2*1/*2 were recruited for this study. The subjects were given 0.32 g ethanol/kg body weight in the form of commercially available beer (5%, v/v). The results showed that BAC-max differed greatly among individuals with a more than two-fold variation. When the BAC-time curve was compared among ADH1B genotypes (ADH1B*1/*1, *1/*2, and *2/*2), there were no differences in BAC among the genotypes. Although BAcH, monthly alcohol consumption, elimination rate of blood ethanol (β value) and ethanol disappearance rate from the body (EDR) can affect BAC, all of them had no correlations with BAC-max. However, Vd (liter/kg), ΔPlasma glucose concentration (ΔPGC = PGC30 min ? PGC0 min) and the serum concentration of gastric inhibitory polypeptide (GIP) did correlate with BAC-max. Model 2 in multiple linear regression analysis showed the optimal model for Vd and GIP with positive correlations with BAC-max. As GIP and ΔPGC are both reflected by gastric emptying rate (GER), we concluded that the individual differences in BAC after moderate drinking are mainly regulated by GER together with Vd. These findings demonstrate that together with body water content, the gastrointestinal tract plays an important role in the regulation of individual differences in BAC, involving first pass metabolism of ethanol. 展开更多
关键词 Individual Differences Blood ETHANOL Concentration MODErate drinking GASTRIC EMPTYING rate Distribution Volume
下载PDF
Diagnostic performance of dynamic contrast-enhanced magnetic resonance imaging parameters and serum tumor markers in rectal carcinoma prognosis
3
作者 Ren-Qi Mu Jun-Wei Lv +3 位作者 Cai-Yun Ma Xiao-Hui Ma Dong Xing Hou-Sheng Ma 《World Journal of Gastrointestinal Oncology》 SCIE 2024年第5期1796-1807,共12页
BACKGROUND Rectal carcinoma(RC),one of the most common malignancies globally,presents an increasing incidence and mortality year by year,especially among young people,which seriously affects the prognosis and quality ... BACKGROUND Rectal carcinoma(RC),one of the most common malignancies globally,presents an increasing incidence and mortality year by year,especially among young people,which seriously affects the prognosis and quality of life of patients.At present,dynamic contrast-enhanced magnetic resonance imaging(DCE-MRI)parameters and serum carbohydrate antigen 19-9(CA19-9)and CA125 Levels have been used in clinical practice to evaluate the T stage and differentiation of RC.However,the accuracy of these evaluation modalities still needs further research.This study explores the application and value of these methods in evaluating the T stage and differentiation degree of RC.AIM To analyze the diagnostic performance of DCE-MRI parameters combined with serum tumor markers(TMs)in assessing pathological processes and prognosis of RC patients.METHODS A retrospective analysis was performed on 104 RC patients treated at Yantai Yuhuangding Hospital from May 2018 to January 2022.Patients were categorized into stages T1,T2,T3,and T4,depending on their T stage and differentiation degree.In addition,they were assigned to low(L group)and moderate-high differentiation(M+H group)groups based on their differentiation degree.The levels of DCE-MRI parameters and serum CA19-9 and CA125 in different groups of patients were compared.In addition,the value of DCE-MRI parameters[volume transfer constant(Ktrans),rate constant(Kep),and extravascular extracellular volume fraction(Ve)in assessing the differentiation and T staging of RC patients was discussed.Furthermore,the usefulness of DCE-MRI parameters combined with serum CA19-9 and CA125 Levels in the evaluation of RC differentiation and T staging was analyzed.RESULTS Ktrans,Ve,CA19-9 and CA125 were higher in the high-stage group and L group than in the low-stage group and M+H Group,respectively(P<0.05).The areas under the curve(AUCs)of the Ktran and Ve parameters were 0.638 and 0.694 in the diagnosis of high and low stages,respectively,and 0.672 and 0.725 in diagnosing moderate-high and low differentiation,respectively.The AUC of DCE-MRI parameters(Ktrans+Ve)in the diagnosis of high and low stages was 0.742,and the AUC in diagnosing moderate-high and low differentiation was 0.769.The AUCs of CA19-9 and CA-125 were 0.773 and 0.802 in the diagnosis of high and low stages,respectively,and 0.834 and 0.796 in diagnosing moderate-high and low differentiation,respectively.Then,we combined DCE-MRI(Ktrans+Ve)parameters with CA19-9 and CA-125 and found that the AUC of DCE-MRI parameters plus serum TMs was 0.836 in the diagnosis of high and low stages and 0.946 in the diagnosis of moderate-high and low differentiation.According to the Delong test,the AUC of DCE-MRI parameters plus serum TMs increased significantly compared with serum TMs alone in the diagnosis of T stage and differentiation degree(P<0.001).CONCLUSION The levels of the DCE-MRI parameters Ktrans and Ve and the serum TMs CA19-9 and CA125 all increase with increasing T stage and decreasing differentiation degree of RC and can be used as indices to evaluate the differentiation degree of RC in clinical practice.Moreover,the combined evaluation of the above indices has a better effect and more obvious clinical value,providing important guiding importance for clinical condition judgment and treatment selection. 展开更多
关键词 Rectal carcinoma Volume transfer constant rate constant Extravascular extracellular volume fraction Serum carbohydrate antigen 19-9 Serum carbohydrate antigen 125
下载PDF
吹扫捕集/气相色谱-质谱联用仪测定饮用水水源地中的1,3-丁二烯和1-溴丙烷
4
作者 董凤娟 黄现统 +2 位作者 张凤菊 许昶磊 黄平 《工业用水与废水》 CAS 2024年第2期97-100,共4页
使用吹扫捕集/气相色谱-质谱联用仪,采用SIM扫描模式对饮用水水源地中的1,3-丁二烯、1-溴丙烷进行了测定,并进行了方法学考察。结果表明,2种物质的线性范围良好,1,3-丁二烯、1-溴丙烷的相关系数分别为0.9999、0.9980;检出限分别为0.2和... 使用吹扫捕集/气相色谱-质谱联用仪,采用SIM扫描模式对饮用水水源地中的1,3-丁二烯、1-溴丙烷进行了测定,并进行了方法学考察。结果表明,2种物质的线性范围良好,1,3-丁二烯、1-溴丙烷的相关系数分别为0.9999、0.9980;检出限分别为0.2和0.3μg/L,定量限分别为0.8和1.2μg/L;高、中、低3个浓度的相对标准偏差在2.6%~7.6%之间;高、中、低3个浓度实际样品的加标回收率在84.0%~122%范围内;替代物的加标回收率在70.4%~103%之间。该方法在本实验室具有较低的检出限、良好的线性和精密度、较高的正确度。 展开更多
关键词 吹扫捕集 气相色谱-质谱联用仪 1 3-丁二烯 1-溴丙烷 饮用水水源地 精密度 加标回收率
下载PDF
Process for improving the ladle free- opening rate for high aluminum steel in continuous casting 被引量:3
5
作者 LIU Junzhan ZHOU Tongjun LUO Hui 《Baosteel Technical Research》 CAS 2015年第1期42-45,共4页
Steel 20Mn23AlV is a type of high aluminum steel with a very low ladle free-opening rate. The aluminum composition of 20Mn23AlV ranges from 1.6% to 2.45% ,which is significantly higher than other types of steel. Accor... Steel 20Mn23AlV is a type of high aluminum steel with a very low ladle free-opening rate. The aluminum composition of 20Mn23AlV ranges from 1.6% to 2.45% ,which is significantly higher than other types of steel. According to the real condition of 40 t ladle in steel-making plant of Baosteel Special Steel Company, previous works show that the key factors affecting the ladle free-opening rate of high aluminum steel in continuous casting are:sand material, accessories baking, ladle nozzle cleaning, the process and amount of adding sand, and the rate of argon stirring during refining. Therefore, improving the ladle filler sand quality, baking all of the raw materials, controlling the addition of ladle filler sand, cleaning the ladle nozzle, and optimizing argon stirring during the refining process can resolve the problem of a low ladle free-opening rate of high aluminum steel caused by the long ladle time of liquid steel. 展开更多
关键词 continuous casting high aluminum steel LADLE free - opening rate
下载PDF
Effect of varying normal stress on stability and dynamic motion of a spring-slider system with rate- and state-dependent friction 被引量:2
6
作者 Changrong He Teng-fong Wong 《Earthquake Science》 2014年第6期577-587,共11页
Incorporating rate and state friction laws, stability of linearly stable (i.e., with stiffness greater than the critical value) spring-slider systems subjected to triggering perturbations was analyzed under variable... Incorporating rate and state friction laws, stability of linearly stable (i.e., with stiffness greater than the critical value) spring-slider systems subjected to triggering perturbations was analyzed under variable normal stress condition, and comparison was made between our results and that of fixed normal stress cases revealed in previous studies. For systems associated with the slip law, the critical mag- nitude of rate steps for triggering unstable slips are found to have a similar pattern to the fixed normal stress case, and the critical velocity steps scale with a/(b - a) when k = kcr for both cases. The rate-step boundaries for the variable normal stress cases are revealed to be lower than the fixed normal stress case by 7 %-16 % for a relatively large ct = 0.56 with (b - a)/a ranging from 0.25 to 1, indicating easier triggering under the variable normal stress condition with rate steps. The difference between fixed and variable normal stress cases decreases when the α value is smaller. In the same slip- law-type systems, critical displacements to trigger instability are revealed to be little affected by the variable normal stress condition. When k 〉 kcr(V,), a spring-slider system with the slowness law is much more stable than with the slip law,suggesting that the slowness law fits experimental data better when a single state variable is adopted. In stick-slip motions, the variable normal stress case has larger stress drops than the constant normal stress case. The variable normal stress has little effect on the range of slip velocity in systems associated with the slowness law, whereas systems associated with the slip law have a slowest slip velocity immensely smaller than the fixed normal stress case, by ~ 10 orders of magnitude. 展开更多
关键词 rate and state friction - Stability Variablenormal stress Stick-slip motion
下载PDF
Experimental Research on the Sterilization of Escherichia Coli and Bacillus Subtilis in Drinking Water by Dielectric Barrier Discharge 被引量:1
7
作者 李洋 依成武 +2 位作者 李京京 依蓉婕 王慧娟 《Plasma Science and Technology》 SCIE EI CAS CSCD 2016年第2期173-178,共6页
The bactericidal effect on the representative type of Gram-negative Escherichia coli(E.coli) and Gram-positive Bacillus subtilis in drinking water was investigated in this paper by using dielectric barrier discharge... The bactericidal effect on the representative type of Gram-negative Escherichia coli(E.coli) and Gram-positive Bacillus subtilis in drinking water was investigated in this paper by using dielectric barrier discharge(DBD) advanced oxidation technology.The sterilizing rates under different conditions of reaction time t,input voltage V,p H value,and initial concentration of bacteria C_0 were investigated to figure out the optimum sterilization conditions.Our observations and comparisons of cell morphology alteration by scanning electron microscopy and transmission electron microscopy revealed the sterilization mechanisms.The results showed that the sterilizing rate increased obviously with the extension of reaction time t and the rise of input voltage V.The optimal sterilization effect was achieved when the p H value was 7.1.As the initial concentration of bacteria rose,the sterilizing rate decreased.When the input voltage was 2.2 k V and the initial concentration of bacteria was relatively low,the sterilizing rate almost reached 100% after a certain treatment time in neutral aqueous solution.The reasons for the great damage of cell structure and the killing of bacteria are the oxidation of O_3,OH and the accumulation of active species produced by DBD.The article provides a certain theoretical and experimental basis for DBD application in water pollution treatment. 展开更多
关键词 E.coli BSN drinking water active species sterilizing rate
下载PDF
Effect of cooling rate on evolution of superconducting phases during decomposition and recrystallization of (Bi,Pb)-2223 core in Ag-sheathed tape 被引量:1
8
作者 LI Jingyong LI Jianguo ZHENG Huiling LI Chengshan LU Yafeng ZHOU Lian 《Rare Metals》 SCIE EI CAS CSCD 2006年第z1期400-404,共5页
The reformation of (Bi,Pb)-2223 from the liquid or melt is very important for a melting process of (Bi,Pb)-2223 tape. By combination of quenching experiment with X-ray diffraction (XRD) analysis, the effect of cooling... The reformation of (Bi,Pb)-2223 from the liquid or melt is very important for a melting process of (Bi,Pb)-2223 tape. By combination of quenching experiment with X-ray diffraction (XRD) analysis, the effect of cooling rate on the evolution of three superconducting phases in the (Bi,Pb)-2223 core of Ag-sheathed tape was investigated. The results show that (Bi,Pb)-2223 reformation from the melt seems to experience different routes during slowly cooling at different rates. One is that (Bi,Pb)-2223 phase reformed directly from the melt, and no Bi-2212 participate in this process. The other is that (Bi,Pb)-2223 is converted from the intermediate product, Bi-2212, which formed from the melt during the first cooling stage. Due to the inherent sluggish formation kinetics of (Bi,Pb)-2223 from Bi-2212, only partial (Bi,Pb)-2223 can finally be reformed with the second route. 展开更多
关键词 (Bi Pb)-2223/Ag tape cooling rate decomposition and reformation
下载PDF
Plastic Flow Modeling of Ti-5 Al-2 Sn-2 Zr-4 Mo-4 Cr Alloy at Elevated Temperatures and High Strain Rates 被引量:1
9
作者 王宝林 AI Xing +1 位作者 刘战强 LIU Jigang 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2015年第3期611-616,共6页
The true stress-sWain relationships of Ti-5A1-2Sn-2Zr-4Mo-4Cr(TC17) alloy with a wide range of strain rates were investigated by tmiaxial quasi-static and dynamic compression tests, respectively. Quasi- static compr... The true stress-sWain relationships of Ti-5A1-2Sn-2Zr-4Mo-4Cr(TC17) alloy with a wide range of strain rates were investigated by tmiaxial quasi-static and dynamic compression tests, respectively. Quasi- static compression tests were carried out with Instron 8874 test machine, while dynamic compression tests were performed with the split Hopkinson pressure bar (SHPB) which was installed with heating device and synchro- assembly system. The dynamic mechanical behaviors tests of TC17 were carded out from room temperature to 800 ℃ at intervals of 200 ℃ and at high sWain rates (5 500-1 9200 s-l). The stress-strain curves considering temperature-sWain rate coupling actions were obtained. The Johnson-Cook constitutive model was developed through data fitting of the stress-sWain curves. The material constants in the developed constitutive model can be determined using isothermal and adiabatic stress-strain curves at different strain rates. The Johnson-Cook constitutive model provided satisfied prediction of the plastic flow stress for TC17 alloy. 展开更多
关键词 Ti-5A1-2Sn-2Zr-4Mo-4Cr SHPB stress-strain curve high temperature high strain rate dynamic constitutive relationship
下载PDF
Performance Analysis of Outage Probability and Error Rate of Square M-QAM in Mobile Wireless Communication Systems over Generalized α-μ Fading Channels with Non-Gaussian Noise
10
作者 Fares S. Aimehmadi Osamah S. Badarneh 《China Communications》 SCIE CSCD 2018年第1期62-71,共10页
This paper derives new and exact closed-form expressions for the average symbol error rate(SER) of square M-ary quadrature amplitude modulation(M-QAM) in wireless communication systems over theα-μfading channels sub... This paper derives new and exact closed-form expressions for the average symbol error rate(SER) of square M-ary quadrature amplitude modulation(M-QAM) in wireless communication systems over theα-μfading channels subject to an additive non-Gaussian noise. The obtained expressions take into account static and mobile wireless receivers. In addition, a closed-form expression for the outage probability in mobile networks is obtained. Please note that all derived expressions in this paper a valid for integer and non-integer values of the fading parameters. Analytical results are presented to study the impact of noise shaping parameter, severity of fading, and mobility on the average SER. Monte-Carlo simulations results are also provided to validate the accuracy of the analytical results. 展开更多
关键词 α-μ FADING SYMBOL error rate NON-GAUSSIAN noise random WAYPOINT mobili-ty model
下载PDF
NO_3^-/NH_4^+ ratios affect plant growth, chlorophyll content,respiration rate, and morphological structure in Malus hupehensis seedlings
11
作者 Yu Dong Huan-huan Zhi +1 位作者 Qian Zhao Jun-feng Guan 《Journal of Forestry Research》 SCIE CAS CSCD 2015年第4期983-991,共9页
Malus hupehensis (Pamp.) Rehd. is a widely cultivated rootstock in China. We studied the effect of three NO3-/NH4+ ratios (100/0, 50/50, and 0/100, molar basis) at total nitrogen (N) concentration of 8 mmoL L-1... Malus hupehensis (Pamp.) Rehd. is a widely cultivated rootstock in China. We studied the effect of three NO3-/NH4+ ratios (100/0, 50/50, and 0/100, molar basis) at total nitrogen (N) concentration of 8 mmoL L-1 in a nutrient solution on M. hupehensis seedlings. Plant biomass, NO3- and NH4+concentrafion, chlorophyll con- tent, respiratory rate, and cellular structure were investi- gated. M. hupehensis seedlings at the NO3-/NH4+ ratio of 50/50 had the highest level of fresh weight, dry weight, shoot length, and chlorophyll (a, b, and a + b) content, but the lowest respiration rate in the leavesand roots. In addition, thickness and numbers of palisade and spongy tissue cells of the leaves were greater with this treatment than with other treatments. At the NO3-/NH4+ ratio of 100/0, the leaves and roots had higher NO3- concentration and lower NH4+ concentration. However, the opposite trend occurred at the NO3-/NH4+ ratio of 0/100. Chloro- phyll (a, b, and a + b) content was lowest at the NO3-/NH4+ ratio of 100/0 than at the other ratios. At the NO3-/ NH4+ ratio of 0/100, oxygen (02) consumption increased in the leaves and roots, and irregular epidermis and cortex cells were observed in the root apical meristematic and mature region. Our results indicated that the NO3-INH4+ ratio at 50/50 was suitable for growth of M. hupehensis seedling to achieve the highest biomass production and efficiency. 展开更多
关键词 Cellular structure Chlorophyll content Malus hupehensis (Pamp.) Rehd. NO3- NH4+ Respiratory rate
下载PDF
THE BROAD-BAND CCD PHOTOMETRY AND DUST PRODUCTION RATES OF COMET HALE-BOPP
12
作者 Huang Keliang 1 Hu Jingyao 2 Zhou Hongnan 1 (1. Department of Physics, Nanjing Normal University, Nanjing 210097) (2. Beijing Observatory, Chinese Academy of Sciences, Beijing 100080) 《中国科学院上海天文台年刊》 2000年第S1期44-50,共7页
Based upon broad-band CCD observation data of comet Hale-Bopp obtained by a 60cm telescope at Xinglong Station of Beijing Astronomical Observatory during March-August, 1996, the photometric results of comet Hale-Bopp ... Based upon broad-band CCD observation data of comet Hale-Bopp obtained by a 60cm telescope at Xinglong Station of Beijing Astronomical Observatory during March-August, 1996, the photometric results of comet Hale-Bopp are reported. Using the photometric results, the dust production rate, radius and mass of nucleus of comet Hale-Bopp are estimated as follows: dM/dt~1.5×10 5 kgs -1, R n~35.5km, and M n~5.65×10 16kg. 展开更多
关键词 COMET HALE-BOPP - CCD PHOTOMETRY - DUST production rate
下载PDF
ASTM E1268-19带状组织评定方法研究
13
作者 杨艳龙 周志超 +2 位作者 赵乃胜 武甲 张秀丽 《山西冶金》 CAS 2023年第7期28-31,共4页
介绍了美标ASTM E1268-19显微组织带状物级别或取向度的评级方法。采用ASTM E1268-19与GB/T13299—91试验方法,评定了热轧板卷试样的珠光体带状组织,并对ASTM E1268标准方法中检测视场的影响因素进行了分析。结果表明:增加检测视场数有... 介绍了美标ASTM E1268-19显微组织带状物级别或取向度的评级方法。采用ASTM E1268-19与GB/T13299—91试验方法,评定了热轧板卷试样的珠光体带状组织,并对ASTM E1268标准方法中检测视场的影响因素进行了分析。结果表明:增加检测视场数有利于提高定量评定结果的准确度;对于带状严重的组织,因其平行测量线容易全部落入单相组织内部或外部,对带状等级BR(banding rate)值的测量结果影响较大,针对此类情况,有必要增加检测视场数或测量线的数量,以提高BR的检测精度。 展开更多
关键词 带状组织 ASTM E1268-19 定量评定 珠光体 带状等级BR(banding rate)
下载PDF
High Strain Rate Induced Plasticity-increasing of Metallic Materials under Tension
14
作者 唐长国 朱金华 周惠久 《Journal of China Textile University(English Edition)》 EI CAS 1998年第4期17-21,共5页
The effect of strain rate on plasticity has been Investigat-ed for three metallic materials with dynamic tension tech-nique. A phenomenon of high strain induced plasticity -increasing was found for tested materials. T... The effect of strain rate on plasticity has been Investigat-ed for three metallic materials with dynamic tension tech-nique. A phenomenon of high strain induced plasticity -increasing was found for tested materials. The elongation of quenched 30CrMnSiNi2A is 14. 5% under 40 m/s loading rate which is more than two times of the 7 % un-der 0. 5 mm/min. This typic high strain rate induced plasticity - Increasing phenomenon is associated with adiabatic heating, strain twinning and suppression of strain - induced - phase transformation. 展开更多
关键词 high STRAIN rate tension PLASTICITY ADIABATIC heating STRAIN TWINNING STRAIN - INDUCED - phase transfor-mation
全文增补中
2020—2022年苏州市生活饮用水中消毒副产物监测结果分析
15
作者 张利明 李刚 +3 位作者 夏瑜 张付刚 许红睿 辜艳琴 《现代食品》 2024年第9期109-113,共5页
为了解江苏省苏州市生活饮用水中消毒副产物(Disinfection By-Products,DBPs)的污染情况,为饮用水安全管理提供依据,按照《生活饮用水标准检验方法》(GB/T 5750—2023),2020—2022年共采集苏州市生活饮用水样852份,其中出厂水276份、末... 为了解江苏省苏州市生活饮用水中消毒副产物(Disinfection By-Products,DBPs)的污染情况,为饮用水安全管理提供依据,按照《生活饮用水标准检验方法》(GB/T 5750—2023),2020—2022年共采集苏州市生活饮用水样852份,其中出厂水276份、末梢水396份、二次供水180份,对水样中12种DBPs进行检测,依据《生活饮用水卫生标准》(GB/T 5749—2022)进行评价。结果表明,除1,2-二氯乙烷、四氯化碳外,苏州市生活饮用水中其他DBPs均有检出,但均在限值标准内,水样的总体合格率为100%;不同类型水样DBPs浓度和检出率差异不显著(P>0.05)。这表明苏州市生活饮用水总体情况较好,但相关部门应仍需加强DBPs监测,做好其健康风险评估工作,为生活饮用水健康风险管理提供科学支撑。 展开更多
关键词 生活饮用水 消毒副产物 检出率
下载PDF
液相色谱-电喷雾质谱联用法测定饮料中的邻苯二甲酸酯 被引量:50
16
作者 刘超 李来生 +1 位作者 王上文 黄丽芳 《色谱》 CAS CSCD 北大核心 2007年第5期766-767,共2页
建立了饮料中邻苯二甲酸酯(PAEs)的液相色谱-电喷雾离子化质谱联用分析方法。采用Lichrospher C-18柱(250mm×4.6mm,5μm),以甲醇-水(甲醇的体积分数从70%线性变化到100%)为流动相,流速为1.0mL/min。质谱采用选择离子监测模式,以各... 建立了饮料中邻苯二甲酸酯(PAEs)的液相色谱-电喷雾离子化质谱联用分析方法。采用Lichrospher C-18柱(250mm×4.6mm,5μm),以甲醇-水(甲醇的体积分数从70%线性变化到100%)为流动相,流速为1.0mL/min。质谱采用选择离子监测模式,以各物质的钠分子离子峰定量。邻苯二甲酸二甲酯、邻苯二甲酸二乙酯、邻苯二甲酸二丁酯和邻苯二甲酸二辛酯的质量浓度分别为10.94~2734.00μg/L,5.38~2692.00μg/L,9.85~2463.00μg/L和9.98~2494.00μg/L时线性关系良好。纯净水和饮料样品中PAEs的回收率分别为94.0%~104.7%和92.5%~102.9%,相对标准偏差小于2.79%。该方法方便、快捷,准确度和灵敏度高。 展开更多
关键词 液相色谱-电喷雾离子化质谱(LC-ESI/MS) 邻苯二甲酸酯(phthalates) 饮料(drinks)
下载PDF
江苏盐城盐都区域生活饮用水微生物检测分析
17
作者 乔小迪 李双 周霞 《中国卫生产业》 2024年第5期205-207,214,共4页
目的分析江苏盐城区域生活饮用水微生物检测结果。方法选取2021年1月—2023年12月盐城市盐都区疾病预防控制中心的953份饮用水样本为研究对象,严格根据相关要求,完成所有饮用水样本的微生物检测工作,并统计检测不合格情况。结果953份饮... 目的分析江苏盐城区域生活饮用水微生物检测结果。方法选取2021年1月—2023年12月盐城市盐都区疾病预防控制中心的953份饮用水样本为研究对象,严格根据相关要求,完成所有饮用水样本的微生物检测工作,并统计检测不合格情况。结果953份饮用水样本中,微生物检测不合格率为9.50%。不同年度不合格率比较,差异无统计学意义(P均>0.05)。相较枯水期,丰水期水质不合格率(7.33%)更高,差异有统计学意义(χ^(2)=9.590,P<0.05)。相比出厂水与末梢水,二次供水检测不合格率更高,差异有统计学意义(P均<0.05)。结论盐城市盐都区域生活饮用水微生物检测不合格率比较低,丰水期水质和二次供水水质略差,需加强水质管理,严格消毒处理,保证生活饮用水质量。 展开更多
关键词 生活饮用水 微生物检测 不合格率 枯水期 二次供水
下载PDF
沈阳经济技术开发区饮用水水源地综合评价研究
18
作者 朱萍娇 潘俊 《环境保护与循环经济》 2024年第5期73-75,共3页
饮用水水源地是一个地区的重要生态屏障,沈阳经济技术开发区工业快速发展,城市规模增大,人口增长,对水资源需求日益增加。运用水文地质钻探等手段对作为饮用水水源的地下水进行了供水水文地质的全面调查和资源评估,详细研究了水源地的... 饮用水水源地是一个地区的重要生态屏障,沈阳经济技术开发区工业快速发展,城市规模增大,人口增长,对水资源需求日益增加。运用水文地质钻探等手段对作为饮用水水源的地下水进行了供水水文地质的全面调查和资源评估,详细研究了水源地的水文地质环境,包括含水岩组在空间上的分布特性、含水层相互之间的水力相互作用及其水文参量等。查明水源地的水文地质条件后,进行沈阳经济技术开发区饮用水水源地综合评价,并提出相关建议,为合理开采及保护地下水资源,满足不断增长的城市需求,制定可靠的供水计划和保障饮用水安全提供重要数据支持,确保环境可持续性发展。 展开更多
关键词 饮用水水源地 水量评级 水质评价 水资源保护
下载PDF
滤膜法和多管发酵法在生活饮用水检测中的应用探讨
19
作者 布蕾楠 《食品安全导刊》 2024年第8期59-61,共3页
为探究多管发酵法和滤膜法在生活饮用水检测中的应用情况,采集2022年、2023年河北省石家庄高新技术产业开发区枯水期(12月至次年4月)生活饮用水90份和丰水期(5—9月)生活饮用水90份,采用滤膜法和多管发酵法进行检验,对比分析两种微生物... 为探究多管发酵法和滤膜法在生活饮用水检测中的应用情况,采集2022年、2023年河北省石家庄高新技术产业开发区枯水期(12月至次年4月)生活饮用水90份和丰水期(5—9月)生活饮用水90份,采用滤膜法和多管发酵法进行检验,对比分析两种微生物检验方法的准确性及在日常生活中的可用性。结果表明,多管发酵法的总检出率显著高于滤膜法。滤膜法在操作简便性和检测效率上优于多管发酵法,而多管发酵法在灵敏度上略胜一筹。在日常水质检测中应用多管发酵法可提高生活饮用水中微生物的检出率,提升居民饮用水的安全性。 展开更多
关键词 生活饮用水 滤膜法 多管发酵法 微生物检出率
下载PDF
A two-parameter model to predict fatigue life of high-strength steels in a very high cycle fatigue regime 被引量:7
20
作者 Chengqi Sun Xiaolong Liu Youshi Hong 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2015年第3期383-391,共9页
In this paper, ultrasonic (20 kHz) fatigue tests were performed on specimens of a high-strength steel in very high cycle fatigue (VHCF) regime. Experimental results showed that for most tested specimens failed in ... In this paper, ultrasonic (20 kHz) fatigue tests were performed on specimens of a high-strength steel in very high cycle fatigue (VHCF) regime. Experimental results showed that for most tested specimens failed in a VHCF regime, a fatigue crack originated from the interior of specimen with a fish-eye pattern, which contained a fine granular area (FGA) centered by an inclusion as the crack origin. Then, a two-parameter model is proposed to predict the fatigue life of high-strength steels with fish-eye mode failure in a VHCF regime, which takes into account the inclusion size and the FGA size. The model was verified by the data of present experiments and those in the literature. Furthermore, an analytic formula was obtained for estimating the equivalent crack growth rate within the FGA. The results also indicated that the stress intensity factor range at the front of the FGA varies within a small range, which is irrespective of stress amplitude and fatigue life. 展开更多
关键词 Very high-cycle fatigue - High-strength steels Fatigue life Inclusion size Crack growth rate
下载PDF
上一页 1 2 17 下一页 到第
使用帮助 返回顶部