期刊文献+
共找到11,099篇文章
< 1 2 250 >
每页显示 20 50 100
Excess pore pressure behavior and evolution in deep coalbed methane reservoirs
1
作者 Changqing Liu Zhaobiao Yang +3 位作者 Yong Qin Xia Yan Yunhai Wang Zhe Wang 《International Journal of Mining Science and Technology》 SCIE EI CAS CSCD 2024年第6期763-781,共19页
Deep coalbed methane(DCBM),an unconventional gas reservoir,has undergone significant advancements in recent years,sparking a growing interest in assessing pore pressure dynamics within these reservoirs.While some prod... Deep coalbed methane(DCBM),an unconventional gas reservoir,has undergone significant advancements in recent years,sparking a growing interest in assessing pore pressure dynamics within these reservoirs.While some production data analysis techniques have been adapted from conventional oil and gas wells,there remains a gap in the understanding of pore pressure generation and evolution,particularly in wells subjected to large-scale hydraulic fracturing.To address this gap,a novel technique called excess pore pressure analysis(EPPA)has been introduced to the coal seam gas industry for the first time to our knowledge,which employs dual-phase flow principles based on consolidation theory.This technique focuses on the generation and dissipation for excess pore-water pressure(EPWP)and excess pore-gas pressure(EPGP)in stimulated deep coal reservoirs.Equations have been developed respectively and numerical solutions have been provided using the finite element method(FEM).Application of this model to a representative field example reveals that excess pore pressure arises from rapid loading,with overburden weight transferred under undrained condition due to intense hydraulic fracturing,which significantly redistributes the weight-bearing role from the solid coal structure to the injected fluid and liberated gas within artificial pores over a brief timespan.Furthermore,field application indicates that the dissipation of EPWP and EPGP can be actually considered as the process of well production,where methane and water are extracted from deep coalbed methane wells,leading to consolidation for the artificial reservoirs.Moreover,history matching results demonstrate that the excess-pressure model established in this study provides a better explanation for the declining trends observed in both gas and water production curves,compared to conventional practices in coalbed methane reservoir engineering and petroleum engineering.This research not only enhances the understanding of DCBM reservoir behavior but also offers insights applicable to production analysis in other unconventional resources reliant on hydraulic fracturing. 展开更多
关键词 Deep coalbed methane CONSOLIDATION excess pore-water pressure excess pore-gas pressure Production data analysis
下载PDF
Excess non-COVID-19-related mortality among inflammatory bowel disease decedents during the COVID-19 pandemic 被引量:1
2
作者 Sarah Rotondo-Trivette Xin-Yuan He +9 位作者 Jamil S Samaan Fan Lv Emily Truong Michaela Juels Anthony Nguyen Xu Gao Jian Zu Yee Hui Yeo Fan-Pu Ji Gil Y Melmed 《World Journal of Gastroenterology》 SCIE CAS 2024年第20期2677-2688,共12页
BACKGROUND The coronavirus disease 2019(COVID-19)pandemic disrupted healthcare in the United States.AIM To investigate COVID-19-related and non-COVID-19-related death and characteristics associated with excess death a... BACKGROUND The coronavirus disease 2019(COVID-19)pandemic disrupted healthcare in the United States.AIM To investigate COVID-19-related and non-COVID-19-related death and characteristics associated with excess death among inflammatory bowel disease(IBD)decedents.METHODS We performed a register-based study using data from the National Vital Statistics System,which reports death data from over 99%of the United States population,from January 1,2006 through December 31,2021.IBD-related deaths among adults 25 years and older were stratified by age,sex,race/ethnicity,place of death,and primary cause of death.Predicted and actual age-standardized mortality rates(ASMRs)per 100000 persons were compared.RESULTS 49782 IBD-related deaths occurred during the study period.Non-COVID-19-related deaths increased by 13.14%in 2020 and 18.12%in 2021[2020 ASMR:1.55 actual vs 1.37 predicted,95%confidence interval(CI):1.26-1.49;2021 ASMR:1.63 actual vs 1.38 predicted,95%CI:1.26-1.49].In 2020,non-COVID-19-related mortality increased by 17.65%in ulcerative colitis(UC)patients between the ages of 25 and 65 and 36.36%in non-Hispanic black(NHB)Crohn’s disease(CD)patients.During the pandemic,deaths at home or on arrival and at medical facilities as well as deaths due to neoplasms also increased.CONCLUSION IBD patients suffered excess non-COVID-19-related death during the pandemic.Excess death was associated with younger age among UC patients,and with NHB race among CD patients.Increased death at home or on arrival and due to neoplasms suggests that delayed presentation and difficulty accessing healthcare may have led to increased IBD mortality. 展开更多
关键词 Inflammatory bowel disease Ulcerative colitis Crohn’s disease COVID-19 excess death Race SEX DISPARITIES
下载PDF
Density of excess modes below the first phonon mode in four-dimensional glasses
3
作者 王利近 胥鼎 张世允 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第7期483-489,共7页
Glasses are known to possess low-frequency excess modes beyond the Debye prediction.For decades,it has been assumed that evolution of low-frequency density of excess modes D(ω) with frequency ω follows a power-law s... Glasses are known to possess low-frequency excess modes beyond the Debye prediction.For decades,it has been assumed that evolution of low-frequency density of excess modes D(ω) with frequency ω follows a power-law scaling:D(ω)~ω~γ.However,it remains debated on the value of γ at low frequencies below the first phonon-like mode in finitesize glasses.Early simulation studies reported γ=4 at low frequencies in two-(2D),three-(3D),and four-dimensional(4D)glasses,whereas recent observations in 2D and 3D glasses suggested γ=3.5 in a lower-frequency regime.It is uncertain whether the low-frequency scaling of D(ω)~ω^(3.5) could be generalized to 4D glasses.Here,we conduct numerical simulation studies of excess modes at frequencies below the first phonon-like mode in 4D model glasses.It is found that the system size dependence of D(ω) below the first phonon-like mode varies with spatial dimensions:D(ω) increases in2D glasses but decreases in 3D and 4D glasses as the system size increases.Furthermore,we demonstrate that the ω^(3.5)scaling,rather than the ω~4 scaling,works in the lowest-frequency regime accessed in 4D glasses,regardless of interaction potentials and system sizes examined.Therefore,our findings in 4D glasses,combined with previous results in 2D and 3D glasses,suggest a common low-frequency scaling of D(ω)~ ω^3.5) below the first phonon-like mode across different spatial dimensions,which would inspire further theoretical studies. 展开更多
关键词 vibrational density of states excess modes four-dimensional glasses SCALING computer simulation
下载PDF
Point-of-care ultrasonography spotlight:Could venous excess ultrasound serve as a shared language for internists and intensivists?
4
作者 Anosh Aslam Khan Hasham Saeed +3 位作者 Ibtehaj Ul Haque Ayman Iqbal Doantrang Du Abhilash Koratala 《World Journal of Critical Care Medicine》 2024年第2期126-136,共11页
Point-of-care ultrasonography(POCUS),particularly venous excess ultrasound(VExUS)is emerging as a valuable bedside tool to gain real-time hemodynamic insights.This modality,derived from hepatic vein,portal vein,and in... Point-of-care ultrasonography(POCUS),particularly venous excess ultrasound(VExUS)is emerging as a valuable bedside tool to gain real-time hemodynamic insights.This modality,derived from hepatic vein,portal vein,and intrarenal vessel Doppler patterns,offers a scoring system for dynamic venous congestion assessment.Such an assessment can be crucial in effective management of patients with heart failure exacerbation.It facilitates diagnosis,quantification of congestion,prognostication,and monitoring the efficacy of decongestive therapy.As such,it can effectively help to manage cardiorenal syndromes in various clinical settings.Extended or eVExUS explores additional veins,potentially broadening its applications.While VExUS demonstrates promising outcomes,challenges persist,particularly in cases involving renal and liver parenchymal disease,arrhythmias,and situations of pressure and volume overload overlap.Proficiency in utilizing spectral Doppler is pivotal for clinicians to effectively employ this tool.Hence,the integration of POCUS,especially advanced applications like VExUS,into routine clinical practice necessitates enhanced training across medical specialties. 展开更多
关键词 Point-of-care ultrasonography ULTRASOUND Venous excess ultrasound Doppler Congestion Heart failure
下载PDF
A Discussion on the Issue of Excessive Academic Burden among Middle School Students
5
作者 Pinghui Tu 《Journal of Contemporary Educational Research》 2024年第11期6-15,共10页
At present,the heavy academic workload of middle school students is a common problem,which is still questioned by parents,concerned by the government,and hotly debated by society.This paper summarizes the following ei... At present,the heavy academic workload of middle school students is a common problem,which is still questioned by parents,concerned by the government,and hotly debated by society.This paper summarizes the following eight aspects:the difficult content of subject courses,excessive class hours,heavy homework burden,complicated exams,overwhelming study materials,fierce subject competition,prevalent off-campus tutoring,and poor physical and mental health.Recognizing these problems can help to optimize the education and teaching environment and achieve a sustainable enrollment rate. 展开更多
关键词 Middle school students excessive academic burden DISCUSSION
下载PDF
小Excess与开流形的拓扑(英文) 被引量:4
6
作者 徐森林 王作勤 杨芳云 《应用数学》 CSCD 北大核心 2002年第4期7-12,共6页
本文中 ,我们应用比较几何的方法研究开流形的Excess与其拓扑之间的关系 .我们证明了对于一个曲率下有界的开流形 ,当它的Excess被其临界半径的某个函数所界定时 ,它就有有限拓扑型或微分同胚于n维z欧氏空间 .
关键词 excess函数 开流形 有限拓扑型 临界点 比较定理
下载PDF
Impacts of Excessive Soaking on N, P, and K in Substrates Plots and Seedling Growth
7
作者 王甲辰 左强 +4 位作者 谷佳林 肖强 邹国元 张琳 王美菊 《Agricultural Science & Technology》 CAS 2012年第1期158-161,180,共5页
[Objective] The aim was to study on impacts of excessive soaking N, P, and K insubstrate plots of and seedling growth. [Method] Substrate was designed to add additional 1/2 water after saturation and expansion. Dispos... [Objective] The aim was to study on impacts of excessive soaking N, P, and K insubstrate plots of and seedling growth. [Method] Substrate was designed to add additional 1/2 water after saturation and expansion. Disposable excessive soak- ing and regression relation of nutrition infusion of substrate plots were studied by design of 13 time gradient. Plant nutrition absorption and growth effects after sub- strate plots immersed by water were investigated by growing tomato. [Result] Con- centration and time of the three nutrition immersed in water had the regression equation of each, as follows: N=-2E-05t2+0.016 lt+2.0553, P=0.002 2t+2.248 5 and K=0.004 7t+0.875 8. With nutrition loss of the three, however, loss amount was al- most same with variance analysis of regression equation, which may result from its volatilization. Regression equations of P and K were: P=0.125 7t-0.117, and K=0.022 5t.1514, which led to adverse impact on plant absorption of N and K above ground, whose equations were N=20.64e-4E-0.4t, and K=E-06t2-0.011 3t+29.055. Meanwhile, un- der the condition, sound seedling index was not impacted a lot by excessive immer- sion. [Conclusion] This study has provided theoretical reference for guidance of sub- strate plot soaking method, cultivation and regulation, and breeding, as well as agri- cultural production. 展开更多
关键词 Substrate plot Saturation and expansion for absorption excessive water Regression equation
下载PDF
Excess函数的应用(英文)
8
作者 徐森林 邓勤涛 《应用数学》 CSCD 北大核心 2007年第1期1-5,共5页
在本文中,我们研究了曲率有下界的开流形的拓扑,并推广了文[7]中的结果,证明了截曲率有下界的开流形如果它的excess函数被它的临界半径的某个函数所界定时,它就具有有限拓扑型或者微分同胚于Rn.
关键词 excess函数 有限拓扑型 临界点 比较定理
下载PDF
Treating both wastewater and excess sludge with an innovative process
9
作者 HE Sheng-bing, WANG Bao-zhen, WANG Lin, JIANG Yi-feng (School of Municipal & Environmental Engineering, Harbin Institute of Technology, Harbin 150090, China. 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2003年第6期749-756,共8页
The innovative process consists of biological unit for wastewater treatment and ozonation unit for excess sludge treatment. An aerobic membrane bioreactor(MBR) was used to remove organics and nitrogen, and an anaerobi... The innovative process consists of biological unit for wastewater treatment and ozonation unit for excess sludge treatment. An aerobic membrane bioreactor(MBR) was used to remove organics and nitrogen, and an anaerobic reactor was added to the biological unit for the release of phosphorus contained at aerobic sludge to enhance the removal of phosphorus. For the excess sludge produced in the MBR, which was fed to ozone contact column and reacted with ozone, then the ozonated sludge was returned to the MBR for further biological treatment. Experimental results showed that this process could remove organics, nitrogen and phosphorus efficiently, and the removals for COD, NH 3-N, TN and TP were 93.17%, 97.57%, 82.77% and 79.5%, respectively. Batch test indicated that the specific nitrification rate and specific denitrification rate of the MBR were 1.03 mg NH 3-N/(gMLSS·h) and 0.56 mg NOx-N/(gMLSS·h), and denitrification seems to be the rate-limiting step. Under the test conditions, the sludge concentration in the MBR was kept at 5000—6000 mg/L, and the wasted sludge was ozonated at an ozone dosage of 0.10 kgO 3/kgSS. During the experimental period of two months, no excess sludge was wasted, and a zero withdrawal of excess sludge was implemented. Through economic analysis, it was found that an additional ozonation operating cost for treatment of both wastewater and excess sludge was only 0.045 RMB Yuan(USD 0.0054)/m 3 wastewater. 展开更多
关键词 wastewater treatment excess sludge aerobic membrane bioreactor(MBR) anaerobic reactor OZONATION zero withdrawal of excess sludge
下载PDF
Releasing characteristics of phosphorus and other substances during thermal treatment of excess sludge 被引量:26
10
作者 XUE Tao HUANG Xia 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2007年第10期1153-1158,共6页
The releasing characteristics of phosphorus, nitrogen compounds, organics, and some metal cations during thermal treatment of excess sludge were investigated. It was found that during heating not only phosphorus, but ... The releasing characteristics of phosphorus, nitrogen compounds, organics, and some metal cations during thermal treatment of excess sludge were investigated. It was found that during heating not only phosphorus, but also nitrogen compounds, organics, and some metal cations could be released in abundance. The maximum orthophosphate (ortho-P) release of about 90 mg/L in concentration was observed at 50℃ in 1 h. Except for volatile fatty acids (VFAs), comparatively little total nitrogen (TN), total organic carbon (TOC), and metal cations were released at the same time. Such results might favor further process of phosphorus recovery. VFAs were considerably released only at 50℃. Acetic, butyric, and propionic acid were the most abundant components in turn and their releasing profiles exhibited good linear relationship with time (R2 = 0.9977, 0.9624, and 0.8908, respectively). The concentrations of Mg^2+ and K^+ increased with time and temperature during thermal treatment, but Ca^2+ decreased. The release of Mg^2+ and K^+ agreed well with TP release (R^2 = 0.9892 and 0.9476, respectively). Temperature in the experimental range had very little impact on the linear relationships, especially of Mg^2+. Moreover, the parameter of mixed liquor suspended solids (MLSS) was found to be an important factor for thermal sludge treatment as the released ortho-P and total phosphorus (TP) at 50℃ increased more than one-fold when MLSS was increased from 4000 to 8000 mg/L. 展开更多
关键词 phosphorus recovery excess sludge volatile fatty acids (VFAs) metal cations
下载PDF
Effects of Exogenous Silicon on Photosynthetic Capacity and Antioxidant Enzyme Activities in Chloroplast of Cucumber Seedlings Under Excess Manganese 被引量:14
11
作者 FENG Jian-peng SHI Qing-hua WANG Xiu-feng 《Agricultural Sciences in China》 CAS CSCD 2009年第1期40-50,共11页
Effects of silicon on photosynthetic parameters and antioxidant enzymes of chloroplast in cucumber seedlings under excess Mn were studied. Compared with the control, excess Mn significantly inhibited net photosyntheti... Effects of silicon on photosynthetic parameters and antioxidant enzymes of chloroplast in cucumber seedlings under excess Mn were studied. Compared with the control, excess Mn significantly inhibited net photosynthetic rate (Pn), stomatal conductance, as well as the maximum yield of the photosystem II photochemical reactions (Fv/Fm) and the quantum yield of photosysytem II electron transport (Φ PSII), application of Si reversed the negative effects of excess Mn. In the further investigation, it was obtained that application of Si significantly increased the activities of enzymes related with ascorbate-glutathione cycle including ascorbate peroxidase (APX), dehydroascorbate reductase (DHAR) and glutathione reductase (GR) in cucumber chloroplast under excess Mn, this could be responsible for the lower accumulation of H2O2 and lower lipid peroxidation of chloroplast induced by Mn, and resulted in keeping higher photosynthesis. 展开更多
关键词 CUCUMBER excess manganese photosynthesis chlorophyll fluorescence CHLOROPLAST antioxidant enzymes
下载PDF
Updates on the relation of weight excess and reproductive function in men: sleep apnea as a new area of interest 被引量:11
12
作者 Ahmad O Hammoud Douglas T Carrell +2 位作者 Mark Gibson C Matthew Peterson A Wayne Meikle 《Asian Journal of Andrology》 SCIE CAS CSCD 2012年第1期77-81,176,177,共7页
Obesity has a negative effect on male reproductive function. It is associated with low testosterone levels and alteration in gonadotropin secretion. Male obesity has been linked to reduced male fertility. Data regardi... Obesity has a negative effect on male reproductive function. It is associated with low testosterone levels and alteration in gonadotropin secretion. Male obesity has been linked to reduced male fertility. Data regarding the relation of obesity to sperm parameters are conflicting in terms of the nature and magnitude of the effect. New areas of interest are emerging that can help explain the variation in study results, such as genetic polymorphism and sleep apnea. Sleep disorders have been linked to altered testosterone production and hypogonadism in men. It was also correlated to erectile dysfunction. The relation of sleep disorders to male fertility and sperm parameters remains to be investigated. Men with hypogonadism and infertility should be screened for sleep apnea. Treatment of obesity and sleep apnea improves testosterone levels and erectile function. 展开更多
关键词 INFERTILITY male infertility reproductive function sleep apnea weight excess
下载PDF
A novel approach to treat combined domestic wastewater and excess sludge in MBR 被引量:6
13
作者 HE Sheng bing, WANG Bao zhen, WANG Lin, JIANG Yi feng, ZHANG Li\|qiu (School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin 150090, China. 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2003年第5期674-679,共6页
Domestic wastewater was treated by combined anaerobic biofilm aerobic membrane bioreactor(MBR) process, and part biomass in MBR was withdrawn to treat with ozone, then the ozonated sludge was returned to anaerobic in... Domestic wastewater was treated by combined anaerobic biofilm aerobic membrane bioreactor(MBR) process, and part biomass in MBR was withdrawn to treat with ozone, then the ozonated sludge was returned to anaerobic inlet. In aerobic MBR, MLSS and DO were controlled at 3000—3500 mg/L and 0 8 mg/L respectively. Comparing the experimental results of two stages, it was noticed that ozonation did not affect the removal efficiency for organics but had a significant influence on the removals of NH 3 N and TN. During the ozonation period of two months, no excess sludge was wasted, and a zero sludge yield was obtained. 展开更多
关键词 combined anaerobic biofilm aerobic membrane(MBR) domestic wastewater OZONATION excess sludge sludge yield
下载PDF
Excess函数的性质及其应用 被引量:1
14
作者 巩军胜 《甘肃科学学报》 2008年第4期23-25,共3页
证明了Ric(M)≥-(n-1)完备非紧的n维黎曼流形M,若其上某一点的Excess函数有上界(常数)时,M就具有有限拓扑型或微分同胚于Rn.
关键词 RICCI曲率 excess函数 有限拓扑型 微分同胚
下载PDF
Effect of Selenium Supplementation on Activity and mRNA Expression of Type 1 Deiodinase in Mice With Excessive Iodine Intake 被引量:5
15
作者 XUE-FENG YANG XIAO-HUI HOU JIAN XW HUAI-LAN GUO CHEN-JIANG YING XIAO-YI CHEN XIU-FA SUN 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 2006年第4期302-308,共7页
Objective To investigate the effect of selenium supplementation on the selenium status and selenoenzyme, especially the activity and mRNA expression of type 1 deiodinase (D1) in mice with excessive iodine (EI) int... Objective To investigate the effect of selenium supplementation on the selenium status and selenoenzyme, especially the activity and mRNA expression of type 1 deiodinase (D1) in mice with excessive iodine (EI) intake and to explore the mechanism of selenium intervention on iodine-induced abnormities. Methods Weanling female BALB/c mice were given tap water or 3 mg/L of iodine or supplemented with 0.5 mg/L or 1.0 mg/L of selenium in the presence of excessive iodine for 5 months. Selenium status, thyroid hormone level, hepatic and renal D 1 activity and mRNA expression were examined. Results Excessive iodine intake significantly decreased the selenium concentration in urine and liver, and the activity of glutathione peroxidase (GSH-Px) in liver. Meanwhile, serum total T4 (TT4) increased while serum total T3 (TT3) decreased. Hepatic D1 enzyme activity and mRNA expression were reduced by 33% and 86%, respectively. Renal D1 enzyme activity and mRNA were reduced by 30% and 55%, respectively. Selenium supplementation obviously increased selenium concentration, activity of GSH-Px and D1 as well as mRNA expression of D1. However, increasing the supplementation of Se from 0.5 to 1.0 mg/L did not further increase selenoenzyme activity and expression. Conclusion Relative selenium deficiency caused by excessive iodine plays an essential role in the mechanism of iodine-induced abnormalities. An appropriate dose of selenium supplementation exercises a beneficial intervention. 展开更多
关键词 excessive iodine SELENIUM Glutathione peroxidase Type 1 deiodinase
下载PDF
Environmental Implications of Excessive Selenium: A Review 被引量:10
16
作者 A. DENNIS LEMLY(United States Forest Service, Southern Research Station, Coldwater Fisheries Research Unit, Department of Fisheries and Wildlife Sciences, Virginia Tech University, Blacksburg, VA 24061-0321, USA) 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 1997年第4期415-435,共21页
Selenium is a naturally occurring trace element that is nutritionally required in smallamounts but it can become toxic at concentrations only twice those required. The narrow mar-gin between beneficial and harmful lev... Selenium is a naturally occurring trace element that is nutritionally required in smallamounts but it can become toxic at concentrations only twice those required. The narrow mar-gin between beneficial and harmful levels has important implications for human activities thatincrease the amount of selenium in the environment. Two of these activities, disposal of fbssilfuel wastes and agricultural irrigation of arid, seleniferous soils, have poisoned fish andwildlife, and threatened public health at several locations in the United States. Research stud-ies of these episodes have generated a data base that clearly illustrates the environmental hazardof excessive selenium. It is strongly bioaccumulated by aquatic organisms and even slight in-creases in waterborne concentrations can quickly result in toxic effects such as deformed em-bryos and reproductive failure in wildlife. The selenium data base has been very beneficial indeveloping hazard assessment procedures and establishing environmentally sound water qualitycriteria. The two faces of selenium, required nutrient and Potent toxin, make it a particularlyimportant trace element in the health of both animals and man. Because of this paradox, envi-ronmental selenium in relation to agriculture, fisheries, and wildlife wiIl continue to raise im-POrtant land and water management issues for decades to come. If these issues are dealt withusing prudence and the available environmental selenium data base, adverse irnpacts to naturalresources andspublic health can be avoided 展开更多
关键词 In A Review Environmental Implications of excessive Selenium
下载PDF
Excess Commuting in Transitional Urban China:A Case Study of Guangzhou 被引量:5
17
作者 LIU Wangbao HOU Quan 《Chinese Geographical Science》 SCIE CSCD 2016年第5期599-608,共10页
During the reform era, Chinese cities witnessed dramatic institutional transformation and spatial restructuring in general and profound change of commuting patterns in particular. Using household surveys collected in ... During the reform era, Chinese cities witnessed dramatic institutional transformation and spatial restructuring in general and profound change of commuting patterns in particular. Using household surveys collected in Guangzhou, China, in 2001, 2005 and 2010, excess commuting measurements are estimated. Excess commuting shows an overall trend of increasing during 1990–1999, and then declining during 2000–2010. We argue that deepening marketization of the jobs and housing sectors has induced spatial separation of jobs and housing. In other words, institutional transition and urban spatial restructuring are underpinning the changes of commuting patterns in Chinese cities. Excess commuting has strong relationship with individual socio-demographic status, which is by and large due to the increasing flexibilities of jobs and housing location choices enjoyed by urban residents. The findings call for considerations on balancing jobs-housing in making public policies relevant to urban development in general, and land use and transportation in particular. 展开更多
关键词 excess commuting jobs-housing balance spatial restructuring GUANGZHOU China
下载PDF
Excess Molar Volume, Viscosity and Heat Capacity for the Mixture of 1,2-Propanediol-Water at Different Temperatures 被引量:5
18
作者 杨长生 马沛生 +1 位作者 唐多强 靳凤民 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2003年第2期175-180,共6页
Experimental densities, viscosities and heat capacities at different temperatures were presented over the entire mole fraction range for the binary mixture of 1,2-propanediol and water. Density values were used in the... Experimental densities, viscosities and heat capacities at different temperatures were presented over the entire mole fraction range for the binary mixture of 1,2-propanediol and water. Density values were used in the determination of excess molar volumes, VE. At the same time, the excess viscosity was investigated. The values of VE and E were fitted to the Redlich-Kister equation. Good agreement was observed. The excess volumes are negative over the entire range of composition. They show an U-shaped-concentration dependence and decrease in absolute values with increase of temperature. Values of E are negative over the entire range of the composition, and has a trend very similar to that of VE . The analysis shows that at any temperature the specific heat of mixture is a linear function of the composition as x1 > 20%. All the extended lines intersect at one point. An empirical equation is obtained to calculate the specific heat to mixture at any composition and temperature in the experimental range. 展开更多
关键词 VISCOSITY heat capacity DENSITY excess molar volume molecular interaction
下载PDF
Enhancing excess sludge aerobic digestion with low intensity ultrasound 被引量:8
19
作者 丁文川 李懂学 +1 位作者 曾晓岚 龙腾锐 《Journal of Central South University of Technology》 EI 2006年第4期408-411,共4页
In order to enhance the efficiency of aerobic digestion, the excess sludge was irradiated by low intensity ultrasound at a frequency of 28 kHz and acoustic intensity of 0.53 W/cm^2. The results show that the sludge st... In order to enhance the efficiency of aerobic digestion, the excess sludge was irradiated by low intensity ultrasound at a frequency of 28 kHz and acoustic intensity of 0.53 W/cm^2. The results show that the sludge stabilization without ultrasonic treatment can be achieved after 17 d of digestion, whereas the digestion time of ultrasonic groups can be cut by 3-7 d. During the same digestion elapsing, in ultrasonic groups the total volatile suspended solid removal rate is higher than that in the control group. The kinetics of aerobic digestion of excess sludge with ultrasound can also be described with first-order reaction. 展开更多
关键词 low intensity ultrasound excess sludge aerobic digestion KINETICS
下载PDF
Role of insulin and insulin resistance in androgen excess disorders 被引量:7
20
作者 Kursad Unluhizarci Zuleyha Karaca Fahrettin Kelestimur 《World Journal of Diabetes》 SCIE 2021年第5期616-629,共14页
Insulin has complex effects on cell growth,metabolism and differentiation,and these effects are mediated by a cell-surface bound receptor and eventually a cascade of intracellular signaling events.Among the several me... Insulin has complex effects on cell growth,metabolism and differentiation,and these effects are mediated by a cell-surface bound receptor and eventually a cascade of intracellular signaling events.Among the several metabolic and growth-promoting effects of insulin,insulin resistance is defined as an attenuated effect of insulin on glucose metabolism,primarily the limited export of blood glucose into skeletal muscle and adipose tissue.On the other hand,not all the signaling pathways and insulin-responsive tissues are equally affected,and some effects other than the metabolic actions of insulin are overexpressed.Ovaries and the adrenal glands are two examples of tissues remaining sensitive to insulin actions where insulin may contribute to increased androgen secretion.Polycystic ovary syndrome(PCOS)is the most common form of androgen excess disorder(AED),and its pathogenesis is closely associated with insulin resistance.Patients with idiopathic hirsutism also exhibit insulin resistance,albeit lower than patients with PCOS.Although it is not as evident as in PCOS,patients with congenital adrenal hyperplasia may have insulin resistance,which may be further exacerbated with glucocorticoid overtreatment and obesity.Among patients with severe insulin resistance syndromes,irrespective of the type of disease,hyperinsulinemia promotes ovarian androgen synthesis independently of gonadotropins.It is highly debated in whom and how insulin resistance should be diagnosed and treated among patients with AEDs,including PCOS.It is not suitable to administer an insulin sensitizer relying on only some mathematical models used for estimating insulin resistance.Instead,the treatment decision should be based on the constellation of the signs,symptoms and presence of obesity;acanthosis nigricans;and some laboratory abnormalities such as impaired glucose tolerance and impaired fasting glucose. 展开更多
关键词 INSULIN Insulin resistance HYPERINSULINEMIA HYPERANDROGENISM Androgen excess
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部