By using the meteorological data in the pollution boundary layer which was observed in two ground observation sites:coast and land in the river outlet area of Grand Liao River during January-February in 2007,the daily...By using the meteorological data in the pollution boundary layer which was observed in two ground observation sites:coast and land in the river outlet area of Grand Liao River during January-February in 2007,the daily change characteristics of pollute boundary layer in winter in the area were discussed. The results showed that the pollute boundary layer in the river outlet area of Grand Liao River was affected by the sea and land. In the certain weather condition,maybe the sea-land breeze appeared in the low altitude which was below 200 m in the coastal zone. The stability change in the different height in the coastal zone was more stable than in the land zone,and the wind field change in the area was mainly in 300 m low altitude. At night,the temperature inversion often appears in the area,and the thickness of temperature inversion layer is stably during 200-300 m. The thermal internal boundary layer penetrated deeply into the land about 10 km,and the height could reach 800 m. The atmospheric diffusion ability in the coastal area was weaker and stronger in the land area.展开更多
Snacks are an important part of the catering industry,whose spatial pattern distribution will directly affect the behavior of residents and tourists decision-making.Therefore,this paper chose 'Shaxian snacks' ...Snacks are an important part of the catering industry,whose spatial pattern distribution will directly affect the behavior of residents and tourists decision-making.Therefore,this paper chose 'Shaxian snacks' and 'Chengdu snacks' outlets in the downtown area of Beijing as the research object,taking POI data and GIS spatial data as data sources,using GIS spatial analysis and nuclear density estimation method,to make a comparative analysis of the spatial distribution characteristics of snack outlets in downtown of Beijing.The results showed that(1) distribution characteristics of snacks outlets in each district varied greatly.(2) Distribution differences of both snacks outlets in each circle was in significant.(3) Distribution of snacks outlets from the center to the periphery along the ring roads took on the "pyramid type".(4) Distribution of snacks outlet show stronger proximity to road than to subway.Distribution characteristics of the snack outlets included(1) Spatial distribution of the snacks outlets showed weak centrality.(2) The snacks outlets showed significant characteristics of spatial aggregation with great differences in internal structure.According to the above conclusions,combined with municipal planning,this paper according to the classification of the city,put forward suggestions on the distribution of snack outlets in Beijing,(1) Recombine the snack outlets in old urban districts.(2) According to the city functional orientation,redistribute the snack outlets in new urban districts.展开更多
The structure principles under the flow and pressure working conditions are studied, in order to investigate the dynamic characteristics of the electro-hydraulic proportional pressure-flow hybrid valve. According to t...The structure principles under the flow and pressure working conditions are studied, in order to investigate the dynamic characteristics of the electro-hydraulic proportional pressure-flow hybrid valve. According to the structure principles under the two different working conditions, the transfer functions under such conditions are derived. With the transfer functions, some structure elements that may affect its performance, are investigated, afterwards some principles of optimality and effective methods for improving the dynamic performance of the valve are proposed. The conclusions can be used to instruct engineering applications and products designing. The test results conform to the results of the theoretical analysis and simulation, which proves the correctness of the study and simulation works.展开更多
南盘江是珠江源头、云南曲靖人民的母亲河,其综合系统治理关系到曲靖的生态环境改善和经济社会的可持续发展。为精准掌握南盘江流域水污染问题,本研究详细分析了水质时空变化,降雨时城区管网溢流情况,沿岸排污口分布及污染物排放、合流...南盘江是珠江源头、云南曲靖人民的母亲河,其综合系统治理关系到曲靖的生态环境改善和经济社会的可持续发展。为精准掌握南盘江流域水污染问题,本研究详细分析了水质时空变化,降雨时城区管网溢流情况,沿岸排污口分布及污染物排放、合流制截污管网覆盖及漏损情况,南盘江干流闸坝运行调度情况。结果表明:南盘江流域水质劣Ⅴ类,重度污染,水质旱季劣于雨季,支流劣于干流,下游劣于上游,主要超标因子为NH 3-N和TP;当城区降雨量高于约10 mm时,部分支流白石江等雨水口大量生活污水溢流,雨污合流制难以应对降雨天气;干支流共有排口225个,抽检50个排口水质达标率约24%,超标排放情况普遍;曲靖城区城市建设落后,建成区约30 km 2采用雨污合流制,仍有约40%区域未覆盖截污管网;城区人均水资源量760 m 3,仅为云南人均的15.6%,全国的36%,沿岸闸坝蓄水满足农业灌溉用水需求,闸坝运行调度混乱,河道生态流量无法保障。建议以河长制为抓手,加强工业及城镇生活点源污染治理,优化区域水资源配置,推进河道综合治理、理顺管理机制体制,构建快处高效的治理执行体系,形成全社会参与的南盘江治理局面,方能促进南盘江水生态环境质量持续改善,惠及民生,还河于民。展开更多
矿井下常常存在地下水渗积问题,通过控制主泵出水压力,能够有效地排除积水,保持井下环境相对干燥,增强煤矿地下环境的安全性。但由于矿井下的透水后压力负荷通常是不确定的,单纯以压力为传感信号的主泵排水控制的稳定性会受到较大影响,...矿井下常常存在地下水渗积问题,通过控制主泵出水压力,能够有效地排除积水,保持井下环境相对干燥,增强煤矿地下环境的安全性。但由于矿井下的透水后压力负荷通常是不确定的,单纯以压力为传感信号的主泵排水控制的稳定性会受到较大影响,当前排水多以人工观测为主,排水控制智能化实现难度较大。提出一种扬程特性关联下矿井主泵排水智能控制方法。分析矿井下大功率变频式主泵的扬程特性(H-Q),获取变频式主泵排水压力和扬程特性(H-Q)之间的关系。利用这一关系作为传感信号,采用解耦补偿器和神经网络,利用神经网络在线调整比例、积分和微分(proportional integral derivative,PID)控制参数,组建大功率变频式主泵出水压力智能控制器,实现泵出水压力智能控制。通过实验分析证明,研究方法应用后在22 s左右矿井主泵达到最佳状态,过程中产生的相对误差均在0.5%以下。在多次迭代控制下,所提方法的控制延误始终低于0.1 ms。展开更多
Aim： To compare the use of the suprapubic puncture method versus the transurethral method in pressure-flow studies in patients with benign prostatic hyperplasia. Methods： Twenty-three men with benign prostatic hyper...Aim： To compare the use of the suprapubic puncture method versus the transurethral method in pressure-flow studies in patients with benign prostatic hyperplasia. Methods： Twenty-three men with benign prostatic hyperplasia underwent both suprapubic and transurethral pressure-flow studies during a single session. Standard pressure-flow variables were recorded in all patients with both methods, enabling calculation of obstruction using commonly used grading systems, such as the urethral resistance algorithm, the Abrams-Griffith （AG） number and the Schaefer linear nomogram. Results： There were statistically significant differences between the methods in the mean values of maximum flow rate （P 〈 0.05）, detrusor pressure at the maximum flow （P 〈 0.01）, urethral resistance algorithm （P 〈 0.01）, AG number （P 〈 0.01） and maximum cystic capacity （P 〈 0.01）. Of the men in the study, 10 （43.5%） remained in the same Schaefer class with both methods and 18 （78.3%） in the same AG number area. Using the transurethral method, 12 （52.2%） men increased their Schaefer class by one and 1 （4.3%） by two. There were also differences between the suprapubic and transurethral methods using the AG number： 4 （17.4%） men moved from a classification of equivocal to obstructed and 1 （4.3%） from unobstructed to equivocal. Conclusion： The differences between the techniques for measuring intravesical pressure alter the grading of obstruction determined by several of the commonly used classifications. An 8 F transurethral catheter significantly increases the likelihood of a diagnosis of bladder outlet obstruction when compared with the suprapubic method.展开更多
Pressure-flow study(PFS) of micturition is the best method to quantitatively analyse voiding function. It allows us to distinguish voiding lower urinary tract symptoms and low urine flow rate caused by bladder outlet ...Pressure-flow study(PFS) of micturition is the best method to quantitatively analyse voiding function. It allows us to distinguish voiding lower urinary tract symptoms and low urine flow rate caused by bladder outlet obstruction(BOO) from those caused by detrusor underactivity(DU). Voiding dynamics are significantly different in men and women and the established criteria for urodynamic diagnosis in men do not apply to women. Basic principles of voiding mechanics and voiding patterns in asymptomatic women are analyzed. Although attempts have been made to establish a consensus for diagnosis of BOO in women with pressure-flow cutoff, video-urodynamics criteria and nomograms, currently there is no consensus. There is no standard urodynamic test to diagnose and quantify DU in women for which further investigations are needed. Modified projected isovolumetric pressure(to assess detrusor contraction strength) and pressure-flow cutoff criteria have been used. The diagnosis of voiding dysfunction in women is challenging, requiring PFS with very good quality control and often involves integrating clinical and radiographic data to make the final assessment.展开更多
基金Supported by The Special Project of Public Welfare Industry(Meteorology)of Science and Technology Ministry(GYHY200806020)The National Natural Science Fund(40975084)The Science Research Fund of Liaoning Meteorological Bureau(2008008)
文摘By using the meteorological data in the pollution boundary layer which was observed in two ground observation sites:coast and land in the river outlet area of Grand Liao River during January-February in 2007,the daily change characteristics of pollute boundary layer in winter in the area were discussed. The results showed that the pollute boundary layer in the river outlet area of Grand Liao River was affected by the sea and land. In the certain weather condition,maybe the sea-land breeze appeared in the low altitude which was below 200 m in the coastal zone. The stability change in the different height in the coastal zone was more stable than in the land zone,and the wind field change in the area was mainly in 300 m low altitude. At night,the temperature inversion often appears in the area,and the thickness of temperature inversion layer is stably during 200-300 m. The thermal internal boundary layer penetrated deeply into the land about 10 km,and the height could reach 800 m. The atmospheric diffusion ability in the coastal area was weaker and stronger in the land area.
基金Sponsored by Connotative Development-2018 Undergraduate Teaching Construction and Reform Project of College of Resource Environment and Tourism,Capital Normal University
文摘Snacks are an important part of the catering industry,whose spatial pattern distribution will directly affect the behavior of residents and tourists decision-making.Therefore,this paper chose 'Shaxian snacks' and 'Chengdu snacks' outlets in the downtown area of Beijing as the research object,taking POI data and GIS spatial data as data sources,using GIS spatial analysis and nuclear density estimation method,to make a comparative analysis of the spatial distribution characteristics of snack outlets in downtown of Beijing.The results showed that(1) distribution characteristics of snacks outlets in each district varied greatly.(2) Distribution differences of both snacks outlets in each circle was in significant.(3) Distribution of snacks outlets from the center to the periphery along the ring roads took on the "pyramid type".(4) Distribution of snacks outlet show stronger proximity to road than to subway.Distribution characteristics of the snack outlets included(1) Spatial distribution of the snacks outlets showed weak centrality.(2) The snacks outlets showed significant characteristics of spatial aggregation with great differences in internal structure.According to the above conclusions,combined with municipal planning,this paper according to the classification of the city,put forward suggestions on the distribution of snack outlets in Beijing,(1) Recombine the snack outlets in old urban districts.(2) According to the city functional orientation,redistribute the snack outlets in new urban districts.
文摘The structure principles under the flow and pressure working conditions are studied, in order to investigate the dynamic characteristics of the electro-hydraulic proportional pressure-flow hybrid valve. According to the structure principles under the two different working conditions, the transfer functions under such conditions are derived. With the transfer functions, some structure elements that may affect its performance, are investigated, afterwards some principles of optimality and effective methods for improving the dynamic performance of the valve are proposed. The conclusions can be used to instruct engineering applications and products designing. The test results conform to the results of the theoretical analysis and simulation, which proves the correctness of the study and simulation works.
文摘南盘江是珠江源头、云南曲靖人民的母亲河,其综合系统治理关系到曲靖的生态环境改善和经济社会的可持续发展。为精准掌握南盘江流域水污染问题,本研究详细分析了水质时空变化,降雨时城区管网溢流情况,沿岸排污口分布及污染物排放、合流制截污管网覆盖及漏损情况,南盘江干流闸坝运行调度情况。结果表明:南盘江流域水质劣Ⅴ类,重度污染,水质旱季劣于雨季,支流劣于干流,下游劣于上游,主要超标因子为NH 3-N和TP;当城区降雨量高于约10 mm时,部分支流白石江等雨水口大量生活污水溢流,雨污合流制难以应对降雨天气;干支流共有排口225个,抽检50个排口水质达标率约24%,超标排放情况普遍;曲靖城区城市建设落后,建成区约30 km 2采用雨污合流制,仍有约40%区域未覆盖截污管网;城区人均水资源量760 m 3,仅为云南人均的15.6%,全国的36%,沿岸闸坝蓄水满足农业灌溉用水需求,闸坝运行调度混乱,河道生态流量无法保障。建议以河长制为抓手,加强工业及城镇生活点源污染治理,优化区域水资源配置,推进河道综合治理、理顺管理机制体制,构建快处高效的治理执行体系,形成全社会参与的南盘江治理局面,方能促进南盘江水生态环境质量持续改善,惠及民生,还河于民。
文摘矿井下常常存在地下水渗积问题,通过控制主泵出水压力,能够有效地排除积水,保持井下环境相对干燥,增强煤矿地下环境的安全性。但由于矿井下的透水后压力负荷通常是不确定的,单纯以压力为传感信号的主泵排水控制的稳定性会受到较大影响,当前排水多以人工观测为主,排水控制智能化实现难度较大。提出一种扬程特性关联下矿井主泵排水智能控制方法。分析矿井下大功率变频式主泵的扬程特性(H-Q),获取变频式主泵排水压力和扬程特性(H-Q)之间的关系。利用这一关系作为传感信号,采用解耦补偿器和神经网络,利用神经网络在线调整比例、积分和微分(proportional integral derivative,PID)控制参数,组建大功率变频式主泵出水压力智能控制器,实现泵出水压力智能控制。通过实验分析证明,研究方法应用后在22 s左右矿井主泵达到最佳状态,过程中产生的相对误差均在0.5%以下。在多次迭代控制下,所提方法的控制延误始终低于0.1 ms。
文摘Aim： To compare the use of the suprapubic puncture method versus the transurethral method in pressure-flow studies in patients with benign prostatic hyperplasia. Methods： Twenty-three men with benign prostatic hyperplasia underwent both suprapubic and transurethral pressure-flow studies during a single session. Standard pressure-flow variables were recorded in all patients with both methods, enabling calculation of obstruction using commonly used grading systems, such as the urethral resistance algorithm, the Abrams-Griffith （AG） number and the Schaefer linear nomogram. Results： There were statistically significant differences between the methods in the mean values of maximum flow rate （P 〈 0.05）, detrusor pressure at the maximum flow （P 〈 0.01）, urethral resistance algorithm （P 〈 0.01）, AG number （P 〈 0.01） and maximum cystic capacity （P 〈 0.01）. Of the men in the study, 10 （43.5%） remained in the same Schaefer class with both methods and 18 （78.3%） in the same AG number area. Using the transurethral method, 12 （52.2%） men increased their Schaefer class by one and 1 （4.3%） by two. There were also differences between the suprapubic and transurethral methods using the AG number： 4 （17.4%） men moved from a classification of equivocal to obstructed and 1 （4.3%） from unobstructed to equivocal. Conclusion： The differences between the techniques for measuring intravesical pressure alter the grading of obstruction determined by several of the commonly used classifications. An 8 F transurethral catheter significantly increases the likelihood of a diagnosis of bladder outlet obstruction when compared with the suprapubic method.
文摘Pressure-flow study(PFS) of micturition is the best method to quantitatively analyse voiding function. It allows us to distinguish voiding lower urinary tract symptoms and low urine flow rate caused by bladder outlet obstruction(BOO) from those caused by detrusor underactivity(DU). Voiding dynamics are significantly different in men and women and the established criteria for urodynamic diagnosis in men do not apply to women. Basic principles of voiding mechanics and voiding patterns in asymptomatic women are analyzed. Although attempts have been made to establish a consensus for diagnosis of BOO in women with pressure-flow cutoff, video-urodynamics criteria and nomograms, currently there is no consensus. There is no standard urodynamic test to diagnose and quantify DU in women for which further investigations are needed. Modified projected isovolumetric pressure(to assess detrusor contraction strength) and pressure-flow cutoff criteria have been used. The diagnosis of voiding dysfunction in women is challenging, requiring PFS with very good quality control and often involves integrating clinical and radiographic data to make the final assessment.
