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Flow characteristics and regime transition of aqueous foams in porous media over a wide range of quality,velocity,and surfactant concentration 被引量:1
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作者 Bin-Fei Li Meng-Yuan Zhang +3 位作者 Zhao-Min Li Anthony Kovscek Yan Xin Bo-Liang Li 《Petroleum Science》 SCIE EI CAS CSCD 2023年第2期1044-1052,共9页
Aqueous foam is broadly applicable to enhanced oil recovery(EOR).The rheology of foam as a function of foam quality,gas and liquid velocities,and surfactant concentration constitute the foundation of its application.T... Aqueous foam is broadly applicable to enhanced oil recovery(EOR).The rheology of foam as a function of foam quality,gas and liquid velocities,and surfactant concentration constitute the foundation of its application.The great variations of the above factors can affect the effectiveness of N2 foam in EOR continuously in complex formations,which is rarely involved in previous relevant studies.This paper presents an experimental study of foam flow in porous media by injecting pre-generated N2 foam into a sand pack under the conditions of considering a wide range of gas and liquid velocities and surfactant concentrations.The results show that in a wide range of gas and liquid velocities,the pressure gradient contours are L-shaped near the coordinate axes,but V-shaped in other regions.And the surfactant concentration is a strong factor influencing the trend of pressure gradient contours.Foam flow resistance is very sensitive to the surfactant concentration in both the high-and low-foam quality regime,especially when the surfactant concentration is less than CMC.The foam quality is an important variable to the flow resistance obtained.There exists a transition point from low-to high-quality regime in a particular flow system,where has the maximum flow resistance,the corresponding foam quality is called transition foam quality,which increases as the surfactant concentration increases.The results can add to our knowledge base of foam rheology in porous media,and can provide a strong basis for the field application of foams. 展开更多
关键词 Foam flow regime and transition Porous media Pressure gradient Flow velocity Surfactant concentration Foam quality
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Effects of Different Nitrogen Fertilizer Levels on Fe,Mn,Cu and Zn Concentrations in Shoot and Grain Quality in Rice (Oryza sativa) 被引量:33
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作者 HAO Hu-lin WEI You-zhang YANG Xiao-e FENG Ying WU Chun-yong 《Rice science》 SCIE 2007年第4期289-294,共6页
In a pot experiment, effects of N fertilizer application on the concentrations of Fe, Mn, Cu and Zn in shoot of rice and the quality of brown rice were studied. In the treatments with N fertilizer application, the con... In a pot experiment, effects of N fertilizer application on the concentrations of Fe, Mn, Cu and Zn in shoot of rice and the quality of brown rice were studied. In the treatments with N fertilizer application, the concentrations of Fe, Mn, Cu and Zn in most parts of rice shoot increased compared with control (no N fertilizer application). This indicated that the transportation ability of microelements from root to shoot in rice was improved with N fertilizer application. Effect of N fertilizer on IR68144 was similar to that of on IR64, but the concentrations of the microelements in plant differed, suggesting that the characteristic expression of the two rice genotypes was not controlled by the amount of N fertilizer supplied. The concentrations of those microelements in brown rice increased at first and then decreased with increasing N fertilizer application, reaching the highest at 160 kg/ha, at which the Fe, Mn, Cu and Zn concentrations in brown rice increased by 28.96%, 41.34%, 58.31% and 16.0% for IR64, and by 22.16%, 13.75%, 8.75% and 20.21% for IR68144 compared with control, respectively. Moreover, N fertilizer promoted the accumulation of protein, decreased the accumulation of amylose in grain, and enhanced gel consistency of brown rice. These results indicate that appropriate N fertilizer management could increase micronutrient contents in grain and improve nutrition quality of rice. 展开更多
关键词 RICE nitrogen fertilizer microelement quality trait nutrient concentration protein content amylose content
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Air Pollution Concentration Approach to Potential Area Selection of the Air Quality Monitoring Station in Nakhon Ratchasima Municipality, Thailand 被引量:1
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作者 Patiwat Littidej Sunya Sarapirome Warunee Aunphoklang 《Journal of Environmental Science and Engineering(A)》 2012年第4期484-494,共11页
The purpose of the study is to generate traffic air information system) to determine a proper zone of AQMS (air analyzed were carbon monoxide (CO), and nitrogen oxides (NOx) pollution map using mathematical mode... The purpose of the study is to generate traffic air information system) to determine a proper zone of AQMS (air analyzed were carbon monoxide (CO), and nitrogen oxides (NOx) pollution map using mathematical model and GIS (geographic quality monitoring station) in municipality area. The pollutants which can be harmful to people living in the area. The three steps of mapping process were performed under the GIS environment using the existing vehicle emission rates and pollutant dispersion model. First, traffic volume, road network, and the emission rates of road segments varying with types of vehicle were collected from existing data. Second, the pollutant concentrations were calculated by use of CALINE4, a tool with Gaussian dispersion model. The model parameters include emission rate, wind directions and speeds, ambient temperature and observed pollutant concentration, and atmospheric stability during all seasons from the January 1, 2010 to May 31,2011 with regardless the rainy season. This resulted in concentrations at many receptor points along links of the road network. Third, distributions of pollution concentrations were generated by means of the spatial interpolation of those from receptors. The results of pollution raster-based maps are used for determining frequency of violence and combined pollution map. The resulting frequency of violence and intensity concentration will be further integrated to determine a potential area of AQMS. Finally, achieving pollution potential area of AQMS can be located as helpful basic data for efficient traffic and transportation planning. 展开更多
关键词 Frequency of violence intensity concentration AQMS (air quality monitoring station) dispersion model CALINE4 Nakhon Ratchasima Thailand.
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Relationship Between the N Concentration of the Leaf Subtending Boll and the Cotton Fiber Quality
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作者 WANG You-hua ZHAO Xin-hua +2 位作者 CHEN Bing-lin GAO Xiang-bin ZHOU Zhi-guo 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2012年第12期2013-2019,共7页
This experiments were conducted in Nanjing (118~50"E, 32~02"N) and Xuzhou (117~11 "E, 34~15"N), Jiangsu Province, China, to study the response of fiber quality to the N concentration of the leaf subtending bol... This experiments were conducted in Nanjing (118~50"E, 32~02"N) and Xuzhou (117~11 "E, 34~15"N), Jiangsu Province, China, to study the response of fiber quality to the N concentration of the leaf subtending boll in cotton (Gossypium hirsutum L.). Results suggested that the N dilution curve of the leaf subtending boll can accurately indicate the stage- specific plant N status for fiber development. Fiber strength is likely to be the most variable fiber quality index responding to the leaf N variation which is different in cultivars. Fiber length was the most stable index among strength, length, micronaire, and elongation. There existed an optimum leaf N concentration for fiber strength development in each stage. The optimum leaf N regression curve was very close to the N dilution curve in the middle positional fruiting branches under the 240 kg N ha-1 soil N application rate. 展开更多
关键词 COTTON fiber quality leaf N concentration CELLULOSE
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Production quality and pricing strategy for substitutable products under comparison effects
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作者 Huanyu Yue Yifan Xu 《Journal of Management Science and Engineering》 CSCD 2023年第4期529-557,共29页
Comparison effects have been studied extensively in many fields.In particular,existing operations management articles have discussed the impact of comparison effects on enterprises'production and pricing decisions... Comparison effects have been studied extensively in many fields.In particular,existing operations management articles have discussed the impact of comparison effects on enterprises'production and pricing decisions.Research has also shown that consumers'purchasing decisions are primarily determined by three factors:product quality,selling price,and comparison effects.The current study introduces the concepts of social and temporal comparison effects to examine how comparison effects influence a monopolist's production quality and pricing strategy for substitutable products.Results reveal the following:(1)Setting different prices for even two types of substitutable products with negligible quality differences can divide customers into three groups under the influence of social comparison effects in a single-stage model.(2)The monopolist should avoid using a price discrimination strategy in which products with a short market life cycle have the same quality but different prices.(3)When the market life cycle of products is sufficiently long in the single-product market and the market with two substitutable products,the monopolist's optimal choice in the second stage is to keep production quality constant and increase the selling price.Consequently,the number of buyers does not decrease because of temporal comparison effects.Therefore,the firm increases its revenue.(4)For the market with two substitutable products with quality differences,one approximate optimal strategy for the enterprise in the second stage is to keep the selling price constant with the assumption that product quality cannot be adjusted after the first period.At this point,the consumption situation in the market is the same as that in the first stage.Therefore,when no external constraints exist,the monopolist firm can obtain more benefits in the second stage than in the first stage by exploiting the temporal comparison effects of consumers in the second stage.(5)When consumer identity information can be confirmed in the market,social comparison effects,similar to temporal comparison effects,could help the enterprise increase its price and profit while maintaining product quality.These social and temporal comparison effects constrain consumers.Thus,the number of people who continueto buyproducts does not decrease. 展开更多
关键词 Production quality and pricing strategy Behavioral operations Social comparison effects Temporal comparison effects
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A novel method for geometric quality assurance of rock joint replicas in direct shear testing-Part 1:Derivation of quality assurance parameters and geometric reproducibility
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作者 J.Larsson F.Johansson +3 位作者 D.Mas Ivars E.Johnson M.Flansbjer N.W.Portal 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2023年第9期2193-2208,共16页
Since each rock joint is unique by nature,the utilization of replicas in direct shear testing is required to carry out experimental parameter studies.However,information about the ability of the replicas to simulate t... Since each rock joint is unique by nature,the utilization of replicas in direct shear testing is required to carry out experimental parameter studies.However,information about the ability of the replicas to simulate the shear mechanical behavior of the rock joint and their dispersion in direct shear testing is lacking.With the aim to facilitate generation of high-quality direct shear test data from replicas,a novel component in the testing procedure is introduced by presenting two parameters for geometric quality assurance.The parameters are derived from surface comparisons of three-dimensional(3D)scanning data of the rock joint and its replicas.The first parameter,smf,captures morphological deviations between the replica and the rock joint surfaces.smf is derived as the standard deviation of the deviations between the coordinate points of the replica and the rock joint.Four sources of errors introduced in the replica manufacturing process employed in this study could be identified.These errors could be minimized,yielding replicas with smf0.06 mm.The second parameter is a vector,VHp100,which describes deviations with respect to the shear direction.It is the projection of the 100 mm long normal vector of the best-fit plane of the replica joint surface to the corresponding plane of the rock joint.VHp100was found to be less than or equal to 0.36 mm in this study.Application of these two geometric quality assurance parameters demonstrates that it is possible to manufacture replicas with high geometric similarity to the rock joint.In a subsequent paper(part 2),smf and VHp100 are incorporated in a novel quality assurance method,in which the parameters shall be evaluated prior to direct shear testing.Replicas having parameter values below established thresholds shall have a known and narrow dispersion and imitate the shear mechanical behavior of the rock joint. 展开更多
关键词 Three-dimensional(3D)scanning Geometric reproducibility Geometric quality assurance Replicas Rock joint Surface comparisons
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Effects of Controlled Atmospheres with High_O_2 or High_CO_2 Concentrations on Postharvest Physiology and Storability of "Napoleon" Sweet Cherry 被引量:27
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作者 姜爱丽 田世平 徐勇 《Acta Botanica Sinica》 CSCD 2002年第8期925-930,共6页
Sweet cherries ( Prunus avium L. cv. Napoleon) were stored in controlled atmospheres (CA) of high O(2) (70% O(2) + 0% CO(2)) or high CO(2) (5% O(2) + 10% CO(2)), in modified atmosphere package (MAP, (13% - 18%) O(2) +... Sweet cherries ( Prunus avium L. cv. Napoleon) were stored in controlled atmospheres (CA) of high O(2) (70% O(2) + 0% CO(2)) or high CO(2) (5% O(2) + 10% CO(2)), in modified atmosphere package (MAP, (13% - 18%) O(2) + (2% -4%) CO(2)) and in air (control) at 1 degreesC to investigate the effects of different O(2) and CO(2) concentrations on physiological properties, quality and storability of the fruits during storage. The results indicated that compared with other treatments, CA with high O(2) concentration decreased fruit decay and ethanol content, but increased the accumulation of malondialdehyde (MDA) and stimulated browning. CA with high CO(2) concentration inhibited polyphenol oxidase (PPO) activity, reduced MDA content, maintained vitamin C content and firmness, decreased fruit decay and browning. Soluble solids contents (SSC) were not significantly affected by different atmosphere treatments. 'Napoleon' fruits stored in 5% O(2) + 10% CO(2) for as long as 80 d were of good quality, but only 40, 20 and 30 d stored in MAP, 70% O(2) + 0% CO(2) and air, re-spectively. 展开更多
关键词 sweet cherry physiological properties quality STORABILITY high O(2) concentrations high CO(2) concentrations
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Monitoring Ambient Air Quality in the Carpathian Region of Ukraine
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作者 Sergiy Kurta Ihor Mykytyn +1 位作者 Alexandra Voronych Viktoria Ribun 《Journal of Chemistry and Chemical Engineering》 2018年第1期31-37,共7页
Ivano-Frankivsk oblast is located in the south-western part of Ukraine, close to the geographical center of Europe at the junction of the two major geographic units, the East European Plain and the Eastern Carpathians... Ivano-Frankivsk oblast is located in the south-western part of Ukraine, close to the geographical center of Europe at the junction of the two major geographic units, the East European Plain and the Eastern Carpathians (the Carpathian region of Ukraine). Between September 2013 and September 2015, the expert group of the Department of Organic and Analytical Chemistry of Vasyl Stefanyk Precarpathian National University conducted the mobile monitoring of air cleanliness in Ivano-Frankivsk region; the authors monitored the level of air contamination with seven gases: carbon monoxide and dioxide, sulfur dioxide, nitrogen dioxide, hydrogen sulfide, ammonia, formaldehyde, beta-particles, and gamma radiation. For this purpose, there were used six automatic analyzers "Dozor-C-P", the formaldehyde Gas Analyzer "MIC-98170", and the radiometer "TERRA". The monitoring resulted in the making of three maps of Ivano-Frankivsk region, on which the average levels of concentration of three particular gases (CO2, SO2, and CH20) throughout all the districts of the oblast were marked. There was registered the excess of CH20 limits--the consequences of the presence of the chipboard and wood-fiber production, for which formaldehyde is used as a raw material. Also there was observed the excess of SO2 in the air caused by gas fumes from vehicles and thermal power stations. 展开更多
关键词 MONITORING precarpathian air quality concentration radiation air pollution MC (maximum concentration).
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Do Ureaplasma urealyticum infections in the genital tract affect semen quality? 被引量:30
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作者 Yan Wang Cui-Ling Liang +3 位作者 Jun-Qing Wu Chen Xu Shi-Xiao Qin Er-Sheng Gao 《Asian Journal of Andrology》 SCIE CAS CSCD 2006年第5期562-568,共7页
Aim: To investigate the relationship between Ureaplasma urealyticum (UU) infection and semen quality. Methods: From 2001 to 2003, 346 eligible patients aged 20-45 years were invited from two hospitals in Shanghai,... Aim: To investigate the relationship between Ureaplasma urealyticum (UU) infection and semen quality. Methods: From 2001 to 2003, 346 eligible patients aged 20-45 years were invited from two hospitals in Shanghai, China, to participate in an investigation which included questionnaires about general and reproductive health, an external genital tract examination, UU culture and semen analysis. Multiple linear regression models were used to examine whether UU had a significant effect on semen quality after adjustment for confounding factors. Results: Findings suggested that UU infection was associated with higher semen viscosity and lower semen pH value. Sperm concentration was lower in UU positive subjects than that in UU negative subjects (54.04 × 10^6/mL vs.70.58 × 10^6/mL). However, UU did not significantly affect other semen quality indexes. Conclusion: UU infection of the male genital tract could negatively influence semen quality. 展开更多
关键词 Ureaplasma urealyticum semen quality sperm concentration seminal plasma QUESTIONNAIRE INFECTION
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Study on Nitrogen Distribution in Leaf, Stem and Sheathat Different Layers in Winter Wheat Canopyand Their Influence on Grain Quality 被引量:6
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作者 WANGZhi-jie WANGJi-hua +2 位作者 HUANGWen-jiang MAZhi-hong ZHAOMing 《Agricultural Sciences in China》 CAS CSCD 2003年第8期859-866,共8页
Vertical distribution of nitrogen in wheat canopy, nitrogen remobilization and their influence on grain quality of winter wheat were studied. Two winter wheat cultivars, Jingdong8, a common cultivar, and Zhongyou9507,... Vertical distribution of nitrogen in wheat canopy, nitrogen remobilization and their influence on grain quality of winter wheat were studied. Two winter wheat cultivars, Jingdong8, a common cultivar, and Zhongyou9507, a high quality cultivar, were selected. Leaf nitrogen showed an obvious decreasing trend from the canopy top to the ground surface for all treatments in growth duration. There was no apparent vertical nitrogen gradient in stem and sheath of Zhongyou9507 compared with Jingdong8. Zhongyou9507 had more nitrogen remobilization from leaf, stem and sheath than Jingdong8 from middle grain filling to waxening, especially the nitrogen remobilization amount in stem and sheath, which was higher than that in Jingdong8 during growth duration. Higher vertical nitrogen gradients in Jingdong8 at anthesis had disadvantages on its grain quality. But higher vertical nitrogen gradients between middle and lower layers of Jingdong8 at grain filling stage enhanced its grain quality. Higher vertical nitrogen gradients in upper layer at anthesis and upper layer leaf and middle layer stem and sheath at grain filling stage had advantages on protein accumulation in grain of Zhongyou9507. There were positive correlations between foliar nitrogen remobilization amount and grain quality at later growth stage for the two cultivars. There was a positive correlation between quality of Jingdong8 and stem and sheath nitrogen remobilization amount from anthesis to early grain filling, and that of Zhongyou9507 emerged from anthesis to early grain filling and from middle grain filling to waxening. Contribution of leaf nitrogen to the quality of Jingdong8 was larger than nitrogen from stem and sheath. High protein content of Zhongyou9507 was attributed to the nitrogen condition in its leaf, stem and sheath. Nitrogen in stem and sheath played a more important role on the grain quality of Zhongyou9507 than on that of Jingdong8. 展开更多
关键词 Winter wheat Nitrogen concentration Vertical gradients N remobilization amount Processing quality
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A comparison of atmospheric CO_2 concentration GOSAT-based observations and model simulations 被引量:6
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作者 LEI LiPing GUAN XianHua +3 位作者 ZENG ZhaoCheng ZHANG Bing RU Fei BU Ran 《Science China Earth Sciences》 SCIE EI CAS 2014年第6期1393-1402,共10页
Satellite observations of atmospheric CO2 are able to truly capture the variation of global and regional CO2 concentration.The model simulations based on atmospheric transport models can also assess variations of atmo... Satellite observations of atmospheric CO2 are able to truly capture the variation of global and regional CO2 concentration.The model simulations based on atmospheric transport models can also assess variations of atmospheric CO2 concentrations in a continuous space and time,which is one of approaches for qualitatively and quantitatively studying the atmospheric transport mechanism and spatio-temporal variation of atmospheric CO2 in a global scale.Satellite observations and model simulations of CO2 offer us two different approaches to understand the atmospheric CO2.However,the difference between them has not been comprehensively compared and assessed for revealing the global and regional features of atmospheric CO2.In this study,we compared and assessed the spatio-temporal variation of atmospheric CO2 using two datasets of the column-averaged dry air mole fractions of atmospheric CO2(XCO2)in a year from June 2009 to May 2010,respectively from GOSAT retrievals(V02.xx)and from Goddard Earth Observing System-Chemistry(GEOS-Chem),which is a global 3-D chemistry transport model.In addition to the global comparison,we further compared and analyzed the difference of CO2 between the China land region and the United States(US)land region from two datasets,and demonstrated the reasonability and uncertainty of satellite observations and model simulations.The results show that the XCO2 retrieved from GOSAT is globally lower than GEOS-Chem model simulation by 2 ppm on average,which is close to the validation conclusion for GOSAT by ground measures.This difference of XCO2 between the two datasets,however,changes with the different regions.In China land region,the difference is large,from 0.6 to 5.6 ppm,whereas it is 1.6 to 3.7 ppm in the global land region and 1.4 to 2.7 ppm in the US land region.The goodness of fit test between the two datasets is 0.81 in the US land region,which is higher than that in the global land region(0.67)and China land region(0.68).The analysis results further indicate that the inconsistency of CO2concentration between satellite observations and model simulations in China is larger than that in the US and the globe.This inconsistency is related to the GOSAT retrieval error of CO2 caused by the interference among input parameters of satellite retrieval algorithm,and the uncertainty of driving parameters in GEOS-Chem model. 展开更多
关键词 GOSAT GEOS-CHEM atmospheric CO2 concentration INCONSISTENCY regional comparison
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WATER RESOURCES TRANSFORMATION AND WATER QUALITY VARIATION IN THE URUMQI RIVER BASIN 被引量:2
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作者 曲耀光 骆鸿珍 《Chinese Geographical Science》 SCIE CSCD 1995年第4期325-335,共11页
Like other inland basins in arid regions, the natural vertical zones create special conditions for water resources transformation in the Urumqi River Basin. In the course of water resources transformation and utilizat... Like other inland basins in arid regions, the natural vertical zones create special conditions for water resources transformation in the Urumqi River Basin. In the course of water resources transformation and utilization, the chemical composition and degree of mineralization are influenced by both geographic conditions and human activities. Although the Urumqi River is rather small in runoff and rather short in flow distance, the water quality changes substantially along the river. However, ion concentrations of surface and ground water in the whole basin are relatively low, generally less than 1 g/L. Therefore, the basin is good at providing low-mineralized water. The pollution is not so serious and the water impurity does not surpass the national standard for drinking. As long as people are conscious with protecting water quality and reducing the further water pollution, it is possible for harm of the slight pollution to be eliminated. 展开更多
关键词 WATER RESOURCES TRANSFORMATION WATER quality VARIATION ion concentration
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A continuing 30-year decline in water quality of Jiaojiang Estuary, China 被引量:3
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作者 Chun-ye Wang Bin Zhou Bei Huang 《Water Science and Engineering》 EI CAS CSCD 2015年第1期20-29,共10页
A quantitative description of a long-term series of aquatic environmental factors and their spatial distributions was generated using measured data from the Jiaojiang Estuary from 1982 to 2011. The aquatic environment... A quantitative description of a long-term series of aquatic environmental factors and their spatial distributions was generated using measured data from the Jiaojiang Estuary from 1982 to 2011. The aquatic environmental factors included suspended matter, salinity, and nutrients. Based on these factors, the aquatic ecosystem health in the Jiaojiang Estuary over the last 30 years was analyzed. The results indicated that the suspended matter concentration in the estuary was mainly affected by the amounts of suspended sediment and solid waste, with the value fluctuating over a long period, and the range of high concentration expanded continually; the salinity was mainly affected by precipitation and surface water resources, showing an overall decreasing trend, and the region with low salinity moved seaward and toward the reclamation areas; and the nutritional status, mainly affected by discharge of industrial wastewater and domestic sewage, was satisfactory in the 1980s and 1990s, but the status became severe in recent years. Reclamation had a great influence on these three factors: high reclamation strength led to a significant increase in the suspended matter concentration and a deterioration of the nutritional status, and the reclamation rate was negatively related with the salinity in the estuary. There was a significant positive correlation between the health status of the aquatic ecosystem and salinity, with a correlation coefficient of 0.93. The correlation coefficient between the health status and nutritional status was -0.71, while the correlation between the suspended matter concentration and health status was not as significant as that of the other two factors. The dynamics of the aquatic environment could be divided into four stages: sustainable health from the 1980s to the 1990s, continued deterioration from 2000 to 2003, improvement from 2004 to 2005, and secondary deterioration from 2006 to 2011. The Jiaojiang Estuary is faced with imminent environmental pressure at present. 展开更多
关键词 Water quality decline Aquatic ecosystem health Aquatic environmental factor Suspended matter concentration SALINITY Nutritional status Jiaojiang Estuary
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Environmental mercury exposure, semen quality and reproductive hormones in Greenlandic Inuit and European men: a cross-sectional study 被引量:2
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作者 Emina Mocevic Ina O Specht +5 位作者 Jacob L Marott Aleksander Giwercman Bo AG Jonsson Gunnar Toft Thomas Lundh Jens Peter Bonde 《Asian Journal of Andrology》 SCIE CAS CSCD 2013年第1期97-104,共8页
Several animal studies indicate that mercury is a male reproductive toxicant, but human studies are few and contradictory. We examined semen characteristics and serum levels of reproductive hormones in relation to env... Several animal studies indicate that mercury is a male reproductive toxicant, but human studies are few and contradictory. We examined semen characteristics and serum levels of reproductive hormones in relation to environmental exposure to mercury. Blood and semen samples were collected from 529 male partners of pregnant women living in Greenland, Poland and Ukraine between May 2002 and February 2004. The median concentration of the total content of mercury in whole blood was 9.2 ng ml-1 in Greenland (0.2- 385.8 ng ml-1), 1.0 ng m1-1 in Poland (0.2-6.4 ng ml-z) and 1.0 ng ml-I in Ukraine (0.2-4.9 ng ml-1). We found a significantly positive association between the blood levels of mercury and serum concentration of inhibin B in men from Greenland (p=0.074, 95% confidence interval (CI)=0.021 to 0.126) and in an analysis including men from all three regions (p=0.067, 95% C1=0.024 to O. 110). The association may be due to beneficial effects of polyunsaturated fatty acids (PUFAs), which are contained in seafood and fish. No significant association (P〉O.05) was found between blood concentrations of mercury and any of the other measured semen characteristics (semen volume, total sperm count, sperm concentration, morphology and motility) and reproductive hormones (free androgen index {FAI), follicle-stimulating hormone (FSH), luteinizing hormone (LH), testosterone and LH xtestosterone) in any region. In conclusion, the findings do not provide evidence that environmental mercury exposure in Greenlandic and European men with median whole blood concentration up to 10 ng m1^-1 has adverse effects on biomarkers of male reproductive health. 展开更多
关键词 blood mercury concentration environmental mercury exposure male fertility REPRODUCTION reproductive hormones semen characteristics semen quality
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Single semen analysis as a predictor of semen quality: clinical and epidemiological implications 被引量:1
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作者 Lars Rylander Boel Wetterstrand +6 位作者 Trine B Haugen Gunilla Malm Johan Malm Cathrine Bjorsvik Trine Henrichsen Thomas Saether Aleksander Giwercman 《Asian Journal of Andrology》 SCIE CAS CSCD 2009年第6期723-730,共8页
It is generally thought that a single ejaculate is a bad predictor of semen quality of a subject, because of significant intra-individual variation. Therefore, we investigated the degree to which the results of a firs... It is generally thought that a single ejaculate is a bad predictor of semen quality of a subject, because of significant intra-individual variation. Therefore, we investigated the degree to which the results of a first semen analysis differ from that of a second analysis among men from a how the two different semen results mirrored the overall general population in Norway. In addition, we analysed semen quality assessment. A total of 199 volunteers participated in the study and delivered two semen samples with an interval of 6 months. The semen parameters were determined according to the World Health Organization (WHO) 1999 guidelines, which were also used to determine whether semen quality was normal or abnormal. In addition, the DNA fragmentation index (DFI) was determined using the Sperm Chromatin Structure Assay. The two samples from each individual were very similar with regard to standard semen parameters and DFI (rs: 0.67-0.72), and there were no significant systematic differences between the two samples. The result of the first sample (normal/abnormal) was highly predictive of the overall conclusion based on the two samples (sperm concentration: in 93% of the cases (95% confidence interval [CI]: 89%-96%); sperm motility: in 85% of the cases (95% CI: 79%-89%); overall semen quality: in 85% of the cases (95% CI: 80%-90%). In epidemiological studies, one ejaculate is a sufficient indicator of semen quality in a group of subjects. In a clinical situation, when the question is whether the semen quality is normal or not, the first ejaculate will, in at least 85% of cases, give a correct overall conclusion. 展开更多
关键词 DNA fragmentation intra-individual semen quality semen volume sperm concentration sperm motility
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Grazing impact on forage quality and macronutrient content of rangelands in Qilian Mountains, NW China 被引量:1
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作者 Alina BARANOVA Jens OLDELAND +1 位作者 WANG Shun-li Udo SCHICKHOFF 《Journal of Mountain Science》 SCIE CSCD 2019年第1期43-53,共11页
An important indicator of the rangeland health, associated with land degradation, is the ability of semi-natural rangelands to provide forage of sufficient quality for livestock production. In Qilian Mountains(Gansu P... An important indicator of the rangeland health, associated with land degradation, is the ability of semi-natural rangelands to provide forage of sufficient quality for livestock production. In Qilian Mountains(Gansu Province, NW China) biomass production and forage quality are dependent on the seasonality of precipitation and temperature; most of the precipitation falls during summer season, when sheep, goats and yaks graze mountain rangelands. To sustain the rangelands and to improve the management strategies, the assessment of the forage quality should be implemented. The purpose of this research was to study the response of biomass, forage quality and macronutrient content different levels of grazing intensity in Qilian rangelands. We sampled aboveground biomass in the growing seasons in 2012 and 2013 within spring/autumn or summer grazing regimes in two altitudinal zones below and above 3000 m a.s.l.(montane-subalpine and subalpine-alpine respectively). In order to estimate forage quality, biomass was sampled in 1 m × 1 m plots, assigned to the center of 10 ×10 m sites, fromwhich we collected different indicator parameters of rangeland health. Mineral and fiber content of forage biomass was estimated under different levels of grazing intensity with regard to the growing period. It was found that an increase in grazing intensity led to a decrease in dry matter weight. No linearity was observed in the relationship between nutritive value and grazing intensity. The highest fiber content(59.20 %) was found in plots mostly disturbed by grazing. The highest protein(16.30 %) and the lowest fiber(51.30 %) contents were associated with slightly grazing intensity. Concentrations of the mineral elements, such as Zn, P, K and S varied significantly and showed maximum values under low grazing intensity. 展开更多
关键词 Grazing intensity Nutritive value FORAGE quality Mineral concentrations Alpine Subalpine PASTURES
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Comparison of short-term efficacy between totally laparoscopic gastrectomy and laparoscopic assisted gastrectomy for elderly patients with gastric cancer 被引量:3
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作者 Rui-Yang Zhao Hang-Hang Li +4 位作者 Ke-Cheng Zhang Hao Cui Huan Deng Jing-Wang Gao Bo Wei 《World Journal of Gastrointestinal Surgery》 SCIE 2022年第9期950-962,共13页
BACKGROUND Totally laparoscopic gastrectomy(TLG)entails both gastrectomy and gastrointestinal reconstruction under laparoscopy.Compared with laparoscopic assisted gastrectomy(LAG),TLG has been demonstrated in many stu... BACKGROUND Totally laparoscopic gastrectomy(TLG)entails both gastrectomy and gastrointestinal reconstruction under laparoscopy.Compared with laparoscopic assisted gastrectomy(LAG),TLG has been demonstrated in many studies to require a smaller surgical incision,result in a faster postoperative recovery and less pain and have comparable long-term efficacy,which has been a research hotspot in recent years.Whether TLG is equally safe and feasible for elderly patients remains unclear.AIM To compare the short-term efficacy of and quality of life(QOL)associated with TLG and LAG in elderly gastric cancer(GC)patients.METHODS The clinicopathological data of 462 elderly patients aged≥70 years who underwent LAG or TLG(including distal gastrectomy and total gastrectomy)between January 2017 and January 2022 at the Department of General Surgery,First Medical Center,Chinese PLA General Hospital were retrospectively collected.A total of 232 patients were in the LAG group,and 230 patients were in the TLG group.Basic patient information,clinicopathological characteristics,operation information and QOL data were collected to compare efficacy.Compared with those in the LAG group,intraoperative blood loss in the TLG group was significantly lower(P<0.001),and the time to first flatus and postoperative hospitalization time were significantly shorter(both P<0.001).The overall incidence of postoperative complications in the TLG group was significantly lower than that in the LAG group(P=0.01).Binary logistic regression results indicated that LAG and an operation time>220 min were independent risk factors for postoperative complications in elderly patients with GC(P<0.05).In terms of QOL,no statistically significant differences in various preoperative indicators were found between the LAG group and the LTG group(P>0.05).Compared with the laparoscopic-assisted total gastrectomy group,patients who received totally laparoscopic total gastrectomy had lower nausea and vomiting scores and higher satisfaction with their body image(P<0.05).Patients who underwent laparoscopic-assisted distal gastrectomy were more satisfied with their body image than patients in the totally laparoscopic distal gastrectomy group(P<0.05).CONCLUSION TLG is safe and feasible for elderly patients with GC and has outstanding advantages such as reducing intracorporeal blood loss,promoting postoperative recovery and improving QOL. 展开更多
关键词 Totally laparoscopic gastrectomy Laparoscopic assisted gastrectomy Gastric cancer Elderly patients Efficacy comparison quality of life
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Statistical Evaluation and Regression Analysis of Vehicle Sound Quality 被引量:1
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作者 王养军 舒歌群 卫海桥 《Transactions of Tianjin University》 EI CAS 2006年第4期297-302,共6页
A statistical approach to evaluate the subjective perception of the annoyance caused by the vehicle noise was presented in this paper. After recording the noises of Sanfeng, Huali and Xiali at speeds of 30, 40, 50, 60... A statistical approach to evaluate the subjective perception of the annoyance caused by the vehicle noise was presented in this paper. After recording the noises of Sanfeng, Huali and Xiali at speeds of 30, 40, 50, 60, 70 and 80 km/h respectively, the annoyance of the vehicle noises was evaluated in the testing room using paired comparison method, and the sound quality metrics and subjective annoyance were then distilled. Loudness, sharpness, roughness, periodicity and impulsiveness were selected for each of the vehicle noises. By correlation analysis method, it can be found that loudness has a higher correlation (0.91) with annoyance than other parameters. Meanwhile, sharpness, periodicity, roughness and impulsiveness have correlation with subjective perception with correlation coefficients being 0.84, -0.82, 0.62 and 0.87, respectively. The result of multiple regression analysis shows that calculated annoyance obtained by the regression equation can explain the perceptual annoyance and the regressed evaluation model is feasible to evaluate the sound quality of vehicle. 展开更多
关键词 vehicle noise sound quality ANNOYANCE paired comparison regression analysis
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Surrogate potency assays:Comparison of binding profiles complements dose response curves for unambiguous assessment of relative potencies 被引量:1
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作者 Robert Karlsson Veronica Fridh Asa Frostell 《Journal of Pharmaceutical Analysis》 SCIE CAS CSCD 2018年第2期138-146,共9页
Surface plasmon resonance(SPR) systems are widely used for detailed characterization of antibody activities including antigen and Fc-receptor binding. During the later stages of development, where the focus is to ensu... Surface plasmon resonance(SPR) systems are widely used for detailed characterization of antibody activities including antigen and Fc-receptor binding. During the later stages of development, where the focus is to ensure that established critical quality attributes(CQAs) are maintained during cell culture,purification and formulation processes, analysis is simplified, and relative potencies are often determined. Here, simulation of binding data revealed that relative potency values, determined via parallel line analysis(PLA) and half maximal effective concentration(EC50) analysis accurately reflect changes in active concentration only if binding kinetics remain unchanged. Changes in the association rate constant shifted dose response curves, and therefore relative potencies, in the same way as changes in analyte concentration do. However, for interactions characterized by stable binding, changes in the dissociation rate constant did not result in any shift, suggesting that this type of change may go unnoticed in the dose response curve. Thus, EC50 and PLA analyses of dose response curves obtained with an anti-TNF-α antibody were complemented with the Biacore functionality for sensorgram comparison analysis, whereby changes in antigen and Fc-receptor binding profiles could be detected. Next, analysis of temperature stressed TNF-α antibody revealed that calibration free concentration analysis(CFCA) data correlated perfectly with relative potency values. Together, these results demonstrate that combinations of SPR based dose response curves, sensorgram comparison and CFCA can be used to strengthen the confidence in relative potency assessments, and suggest that SPR can potentially be used as a surrogate potency assay in the quality control of biotherapeutic medicines. 展开更多
关键词 Surface plasmon resonance EC50 Sensorgram comparison Calibration free concentration analysis Surrogate potency assay TNF-A
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The Epidemiology of Cardio-Vascular Diseases in Relation to the Air Quality of Abattoirs in Port Harcourt, Nigeria 被引量:1
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作者 Vincent Ezikornwor Weli Jimmy O. Adegoke Meelubari Barinua Kpang 《World Journal of Cardiovascular Diseases》 2016年第4期94-107,共14页
This study investigated the spatial occurrence of cardiovascular diseases associated with the air quality of selected abattoirs in Port Harcourt. Using the simple random sampling technique, the Trans-Amadi, Rumuokoro,... This study investigated the spatial occurrence of cardiovascular diseases associated with the air quality of selected abattoirs in Port Harcourt. Using the simple random sampling technique, the Trans-Amadi, Rumuokoro, Rukpokwu and Elelenwo abattoirs were selected and used for the study. However, both gases and particulates matter which include NO<sub>2</sub>, SO<sub>2</sub>, H<sub>2</sub>S, CH<sub>4</sub>, CO, PM<sub>2.5</sub>, and PM<sub>10</sub> were collected at distances of 0, 20, 50, 100, 200 m with the aid of a hand held multi-gas monitor. The questionnaire was used to obtain the demographic and socio-economic characteristics of the respondents, duration of job in years, as well as individual frequency of hospital visitation based on symptoms of cardiovascular diseases. The electrocardiogram was employed to diagnose manifestations of ischemic heart disease among the workers especially in the roasting section. Analysis of data collected was done using the Step-wise multiple regression technique. Result showed that occurrence of cardiovascular diseases is a function of pollutant concentration (CO - r = 0.57) at Rumuokoro abattoir;(O<sub>3</sub> - r = 0.40, SO<sub>2 </sub>- r = 0.23, CO - r = 0.14) at Rukpokwu abattoir, duration of exposure (DOE - r = 0.22) at Rumuokoro abattoir, (DOE ? r = 0.40) at Trans-Amadi abattoir;and (DOE - r = 0.20) at Elelenwo abattoir;age of worker (r = 0.06) at Rukpokwu abattoir, (r = 0.30) at Elenlewo abattoir and daily duration on the job (JOBD - r = 0.13) at Elelenwo abattoir. Findings indicate that there is a positive correlation between occurrence of vascular diseases and pollutant concentration, duration of exposure, age and duration on the job but varies from location to location. Periodic epidemiological and air quality assessment of workers at the abattoirs are strongly advocated. 展开更多
关键词 ABATTOIR Cardiovascular Diseases Air quality Pollutant concentration Duration of Exposure
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