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Population Dynamics and Condition Factor of Oreochromis niloticus L. in Two Tropical Small Dams, Tigray (Northern Ethiopia)
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作者 Atakilt Berihun Tadesse Dejenie 《Journal of Agricultural Science and Technology(B)》 2012年第10期1062-1072,共11页
Several dams have been constructed in Ethiopia, East Africa to support electricity and/or irrigation. Fishes were introduced to some of these dams. Thus, the objective of this study was to assess the dynamics and cond... Several dams have been constructed in Ethiopia, East Africa to support electricity and/or irrigation. Fishes were introduced to some of these dams. Thus, the objective of this study was to assess the dynamics and condition factor of Oriochromis niloticus in Korir and Lailay Wukro Dams, Northern Ethiopias. The study was conducted by deploying two gill net, every month in the littoral and pelagic zones of the two dams from August 2011 to May 2012. A total of 524 O. niloticus, 278 from Lailay Wukro and 246 from Korir dams were collected. The monthly catch per unit effort (CPUE) showed significant variation among months, the highest catch was in May and the least was in January 2012 (P 〈 0.000). Catches of fish encountered higher in the littoral (69.1%) than in the pelagic zones (30.9%) (P 〈 0.000). The condition factor of O. niloticus in the two reservoirs remains high, in Korir 2.05 and in Lailay Wukro 1.65 (P 〈 0.000). In these small tropical dams, O. niloticus mature as they are smaller in size (Ls0: TL average 22.5 cm). The ratio of male to female was 1.3:1 (P 〈 0.016). The two dams have favorable condition for high production of O. niloticus. This high potential for fish production in the dams may be sustainable if the local authorities set a regulation to control the illegal fishing activity. 展开更多
关键词 condition factor CPUE IMMATURE MATURE Oreochromis niloticus.
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Length-weight Relationship and Condition Factor of Sarotherodon Melanotheron(Perciformes:cichlidae)from Forcados River Estuary,Niger Delta,Nigeria
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作者 Efe Ogidiaka John Atadiose Betty O.Bekederemo 《Journal of Fisheries Science》 2022年第1期13-18,共6页
Length-weight relationship(LWR),condition factor(k)of the black chin tilapia,Sarotherodon melanotheron(Rüppel,1852)from Forcados River estuary Nigeria was investigated.The fish were collected monthly from fisherm... Length-weight relationship(LWR),condition factor(k)of the black chin tilapia,Sarotherodon melanotheron(Rüppel,1852)from Forcados River estuary Nigeria was investigated.The fish were collected monthly from fishermen for a period of 24 months(between April 2012 and March 2014).699 specimens of the fish species were collected.The Length-weight relationship(LWR)of the fish was evaluated using the equation:W=a L^(b) while the condition factor of the fish was determined using the equation;K=100W L^(b).The standard length of sampled S.melanotheron ranged from 4.15 to 18.92 cm,total length 6.01 and 22.5 cm while the weight ranged from 7.85-286.71 g.The b value 2.1299 was less than 3 indicating that the growth pattern of the fish was allometric.The correlation co-efficient(r)value for S.melanotheron was 0.7528.The condition factor for the combined sexes fluctuated monthly.The length-weight relationships and condition factor of S.melanotheron in Forcados river estuary indicated that the fish were above average condition. 展开更多
关键词 Sarotherodon melanotheron Length-weight relationship condition factor Forcados River estuary Niger Delta
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Uncertainties of landslide susceptibility prediction: Influences of random errors in landslide conditioning factors and errors reduction by low pass filter method 被引量:1
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作者 Faming Huang Zuokui Teng +4 位作者 Chi Yao Shui-Hua Jiang Filippo Catani Wei Chen Jinsong Huang 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第1期213-230,共18页
In the existing landslide susceptibility prediction(LSP)models,the influences of random errors in landslide conditioning factors on LSP are not considered,instead the original conditioning factors are directly taken a... In the existing landslide susceptibility prediction(LSP)models,the influences of random errors in landslide conditioning factors on LSP are not considered,instead the original conditioning factors are directly taken as the model inputs,which brings uncertainties to LSP results.This study aims to reveal the influence rules of the different proportional random errors in conditioning factors on the LSP un-certainties,and further explore a method which can effectively reduce the random errors in conditioning factors.The original conditioning factors are firstly used to construct original factors-based LSP models,and then different random errors of 5%,10%,15% and 20%are added to these original factors for con-structing relevant errors-based LSP models.Secondly,low-pass filter-based LSP models are constructed by eliminating the random errors using low-pass filter method.Thirdly,the Ruijin County of China with 370 landslides and 16 conditioning factors are used as study case.Three typical machine learning models,i.e.multilayer perceptron(MLP),support vector machine(SVM)and random forest(RF),are selected as LSP models.Finally,the LSP uncertainties are discussed and results show that:(1)The low-pass filter can effectively reduce the random errors in conditioning factors to decrease the LSP uncertainties.(2)With the proportions of random errors increasing from 5%to 20%,the LSP uncertainty increases continuously.(3)The original factors-based models are feasible for LSP in the absence of more accurate conditioning factors.(4)The influence degrees of two uncertainty issues,machine learning models and different proportions of random errors,on the LSP modeling are large and basically the same.(5)The Shapley values effectively explain the internal mechanism of machine learning model predicting landslide sus-ceptibility.In conclusion,greater proportion of random errors in conditioning factors results in higher LSP uncertainty,and low-pass filter can effectively reduce these random errors. 展开更多
关键词 Landslide susceptibility prediction conditioning factor errors Low-pass filter method Machine learning models Interpretability analysis
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Influence of the changing environment on food composition and condition factor in Labeo victorianus(Boulenger,1901)in rivers of Lake Victoria Basin,Kenya
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作者 Nelly F.Nakangu Frank O.Masese +3 位作者 James E.Barasa Geraldine K.Matoll Jacques W.Riziki Mulongaibalu Mbalassa 《Aquaculture and Fisheries》 CSCD 2023年第2期227-238,共12页
Labeo victorianus(Boulenger,1901)is one of the endemic fishes in Lake Victoria Basin(LVB)but is now threatened by multiple stressors caused by human activities.We investigated spatial and temporal variability in food ... Labeo victorianus(Boulenger,1901)is one of the endemic fishes in Lake Victoria Basin(LVB)but is now threatened by multiple stressors caused by human activities.We investigated spatial and temporal variability in food composition and condition of L.victorianus in influent rivers of Lake Victoria,Kenya.Sampling was done during the dry and wet seasons by electrofishing.Food composition analysis showed that L.victorianus is a benthophagus and omnivorous species whose diet is dominated by detritus,periphyton and insects.There were differences in food composition among rivers,with significant river X season interactions(PERMANOVA F=11.6,df=4,p=0.001),suggesting that the diet depended on prevailing environmental conditions.In turbid rivers,the diet was dominated by detritus while in less turbid rivers it was dominated by insects and periphyton.Sand and mud also formed a significant part of the diet,which was an indication of a limited occurrence of preferable food items.There were ontogenetic shifts in food composition(PERMANOVA F=4.6,df=3,p=0.001),but also with a spatial interaction(PERMANOVA F=5.6,df=7,p=0.001),further indicating the role of environmental conditions in determining the diet for different size classes.Interestingly,the fish condition did not differ among rivers.This study shows that turbidity and organic matter and nutrient loading determine the diet of L.victorianus in LVB rivers,and provides further justification for the maintenance of water quality as a conservation measure for threatened species. 展开更多
关键词 condition factor FEEDING Labeo victorianus Ontogenetic shifts SEASONALITY TROPICS
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Landslide susceptibility prediction using slope unit-based machine learning models considering the heterogeneity of conditioning factors 被引量:8
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作者 Zhilu Chang Filippo Catani +4 位作者 Faming Huang Gengzhe Liu Sansar Raj Meena Jinsong Huang Chuangbing Zhou 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2023年第5期1127-1143,共17页
To perform landslide susceptibility prediction(LSP),it is important to select appropriate mapping unit and landslide-related conditioning factors.The efficient and automatic multi-scale segmentation(MSS)method propose... To perform landslide susceptibility prediction(LSP),it is important to select appropriate mapping unit and landslide-related conditioning factors.The efficient and automatic multi-scale segmentation(MSS)method proposed by the authors promotes the application of slope units.However,LSP modeling based on these slope units has not been performed.Moreover,the heterogeneity of conditioning factors in slope units is neglected,leading to incomplete input variables of LSP modeling.In this study,the slope units extracted by the MSS method are used to construct LSP modeling,and the heterogeneity of conditioning factors is represented by the internal variations of conditioning factors within slope unit using the descriptive statistics features of mean,standard deviation and range.Thus,slope units-based machine learning models considering internal variations of conditioning factors(variant slope-machine learning)are proposed.The Chongyi County is selected as the case study and is divided into 53,055 slope units.Fifteen original slope unit-based conditioning factors are expanded to 38 slope unit-based conditioning factors through considering their internal variations.Random forest(RF)and multi-layer perceptron(MLP)machine learning models are used to construct variant Slope-RF and Slope-MLP models.Meanwhile,the Slope-RF and Slope-MLP models without considering the internal variations of conditioning factors,and conventional grid units-based machine learning(Grid-RF and MLP)models are built for comparisons through the LSP performance assessments.Results show that the variant Slopemachine learning models have higher LSP performances than Slope-machine learning models;LSP results of variant Slope-machine learning models have stronger directivity and practical application than Grid-machine learning models.It is concluded that slope units extracted by MSS method can be appropriate for LSP modeling,and the heterogeneity of conditioning factors within slope units can more comprehensively reflect the relationships between conditioning factors and landslides.The research results have important reference significance for land use and landslide prevention. 展开更多
关键词 Landslide susceptibility prediction(LSP) Slope unit Multi-scale segmentation method(MSS) Heterogeneity of conditioning factors Machine learning models
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Effects of temperature and diet on length-weight relationship and condition factor of the juvenile Malabar blood snapper(Lutjanus malabaricus Bloch & Schneider, 1801) 被引量:3
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作者 Sabuj Kanti MAZUMDER Simon Kumar DAS +1 位作者 Yosni BAKAR Mazlan Abd.GHAFFAR 《Journal of Zhejiang University-Science B(Biomedicine & Biotechnology)》 SCIE CAS CSCD 2016年第8期580-590,共11页
In this study we aimed to analyze the effects of water temperature and diet on the length-weight rela- tionship and condition of juvenile Malabar blood snapper Lutjanus malabaricus over a 30-d experimental period. The... In this study we aimed to analyze the effects of water temperature and diet on the length-weight rela- tionship and condition of juvenile Malabar blood snapper Lutjanus malabaricus over a 30-d experimental period. The experiment was conducted in the laboratory using a flow-through-sea-water system. The fish were subjected to four different temperatures (22, 26, 30, and 34 ℃) and two diets (commercial pellet and natural shrimp). Fish were fed twice daily. L. malabancus exhibited negative allometric growth (b〈3) at the beginning of the experiment (Day 0) at all temperatures and both diets except for 22 ℃ fed with shrimp, which showed isometric growth (b=3). Conversely, at the end of the experiment (Day 30) fish showed isometric growth (b=3) at 30 ℃ fed with the pellet diet, indicating that the shape of the fish did not change with increasing weight and length, and a positive allometric growth (b〉3) at 30 ℃ fed with shrimp diet, which indicated that fish weight increases faster than their length. The rest of the temperatures represented negative allometric growth (b〈3) on both diet, meaning that fish became lighter with increasing size. The condition factors in the initial and final measurements were greater than 1, indicating the state of health of the fish, except for those fed on a pellet diet at 34 ℃. However, the best condition was obtained at 30 ℃ on both diets. Nev- ertheless, diets did not have a significant effect on growth and condition of juvenile L. malabaricus. The data obtained from this study suggested culturing L. malabaricus at 30 ℃ and feeding on the pellet or shrimp diet, which will optimize the overall production and condition of this commercially important fish species. 展开更多
关键词 Length-weight relationship condition factor TEMPERATURE Growth Aquaculture SNAPPER
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Effects of In-Situ Cadmium Exposure on Morphometric Indices of Anabas testudineus
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作者 Mohd Sham Othman Sharifah Nadrah Syed Idrus +1 位作者 Fazlin Hazirah Mohd Mohd Riduan Abdullah 《Journal of Environmental Protection》 2024年第4期485-496,共12页
Anthropogenic activities have greatly affected water resources on a global scale where the world is experiencing water quality and resources issues. Heavy metal is a crucial group of pollutants that is toxic to the en... Anthropogenic activities have greatly affected water resources on a global scale where the world is experiencing water quality and resources issues. Heavy metal is a crucial group of pollutants that is toxic to the environment even at low concentrations due to its bioaccumulation and biomagnification capabilities in living organisms. The detrimental effects of heavy metals on living organisms are due to their bioaccumulation in the aquatic ecosystem. Cadmium may result in adverse health effects due to its high toxicity. The study is conducted to determine the cadmium exposure effects on the morphometric indices of Anabas testudineus which are the Scaling Coefficient (SC) and Condition Factor (K) of such species. Anabas testudineus is exposed to four different cadmium treatment groups namely the control group, cadmium treatment group of 0.005 mg/L, 0.010 mg/L, and 0.015 mg/L for 16 weeks. The findings of the study have reported inconsistent trends in the values of SC and a decrease in the value of K with increasing cadmium concentration. The trend for the average SC has shown an overall decrease in value while the pattern of the K value is inconsistent in each treatment group with exposure time. Collectively, no significant differences for SC and K of A. testudineus in different treatment groups as well as comparison between treatment groups with time exposure. 展开更多
关键词 CADMIUM Anabas testudineus Scaling Coefficient condition factor
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关于GB 21455—2019《房间空气调节器能效限定值及能源效率等级》与GB19576—2019《单元式空气调节机能效限定值及能效等级》差异对项目影响的讨论
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作者 于振峰 蒋能飞 +1 位作者 温小勇 李春田 《建筑节能(中英文)》 CAS 2024年第5期143-146,共4页
针对GB 21455—2019《房间空气调节器能效限定值及能源效率等级》与GB 19576—2019《单元式空气调节机能效限定值及能效等级》两个规范在全年能源消耗效率(APF)和制冷季节能源消耗效率(SEER)两种能效等级指标值要求的不同,从两者各自的... 针对GB 21455—2019《房间空气调节器能效限定值及能源效率等级》与GB 19576—2019《单元式空气调节机能效限定值及能效等级》两个规范在全年能源消耗效率(APF)和制冷季节能源消耗效率(SEER)两种能效等级指标值要求的不同,从两者各自的适用范围、能效等级数值、引用标准及其适用范围等方面,进行了不同维度的对比分析。为了便于设计人员选择设计依据及相关规范,讨论细化了两者各自的具体用途和使用场所,可供读者参考。如遇两者有交集的情况,建议按较严格的要求取值,避免影响设备招采和项目验收。为确保项目能正确将设计意图落地实施,提出设计人员除设计工作之外,还需配合的其他工作内容。 展开更多
关键词 房间空气调节器 单元式空气调节机 全年能源消耗效率 制冷季节能源消耗效率 适用范围
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风冷模式中央空调节水潜力及影响因素分析
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作者 胡桂全 赵康 《广东水利水电》 2024年第3期43-46,共4页
经实地调研北京市公共建筑领域中央空调使用情况,对风冷模式中央空调适用的建筑规模、高度以及水冷模式中央空调的用水情况进行了分析,研究了新增公共建筑推广使用风冷模式中央空调的节水潜力,从有利因素和不利因素两方面分析了推广使... 经实地调研北京市公共建筑领域中央空调使用情况,对风冷模式中央空调适用的建筑规模、高度以及水冷模式中央空调的用水情况进行了分析,研究了新增公共建筑推广使用风冷模式中央空调的节水潜力,从有利因素和不利因素两方面分析了推广使用风冷模式中央空调的影响因素,提出加强风冷模式中央空调使用的相关研究建议。 展开更多
关键词 风冷模式 中央空调 节水潜力 影响因素
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家用空调器产品监督检验中常见不合格项目解析
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作者 黄耀华 陈敏 《日用电器》 2024年第5期47-52,共6页
制冷量、制冷消耗功率、全年能源消耗效率(APF)和制冷季节能源消耗效率(SEER)、接地措施、连续骚扰(端子电压)这五个项目是家用空气调节器产品在监督检验中常见的不合格项目,本文通过列举具体案例,从标准要求和实测数据等方面,重点分析... 制冷量、制冷消耗功率、全年能源消耗效率(APF)和制冷季节能源消耗效率(SEER)、接地措施、连续骚扰(端子电压)这五个项目是家用空气调节器产品在监督检验中常见的不合格项目,本文通过列举具体案例,从标准要求和实测数据等方面,重点分析了导致不合格产生的客观及主观原因,并给出了相应的整改方案,为企业提升认识、完善设计、加强质控、规范制造提供了有效的改进建议,助力企业生产出符合国家标准要求的合格产品。 展开更多
关键词 家用空气调节器 制冷量 制冷消耗功率 全年能源消耗效率 制冷季节能源消耗效率 接地措施 连续骚扰(端子电压)
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Effect of air-conditioner exposure on semen quality
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作者 Min-LiLu Jun-QingWu +2 位作者 Qiu-YingYang Wei-JinZhou Er-ShengGao 《Asian Journal of Andrology》 SCIE CAS CSCD 2004年第4期354-354,共1页
Aim: To investigate the effect of air-conditioner exposure on semen quality. Methods: The data came from the healthy male volunteers, aged 22 to 30 years, who went to centers for maternity and children health for prem... Aim: To investigate the effect of air-conditioner exposure on semen quality. Methods: The data came from the healthy male volunteers, aged 22 to 30 years, who went to centers for maternity and children health for premarital physical examination in Shanghai, Henan, Zhejiang and Hebei from December 1998 to February 2000. The sampling size is 304. Results: Among the subjects, 90 (29.6 %) had air-conditioner at home and the rest did not. X2-test and multiple logistic regression analyses showed that, the difference between the exposure and control groups was statistically significant in semen volume, sperm density and proportion of sperm with normal morphology. The three indexes were lower in the exposure group. Conclusion: Air-conditioner exposure possibly influences the semen quality. 展开更多
关键词 semen quality AIR-conditionER influencing factors
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Analysis of Meteorological Epidemic Factors and Soil Improvement Controlling Technology of Tobacco Bacterial Wilt (Ralstonia solanacarum)
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作者 Yang Peiwen Yang Qunhui +5 位作者 Ni Ming Guo Yingcheng Xiao Zhixin Hu Zhiming Li Jiarui Yang Mingying 《Plant Diseases and Pests》 CAS 2017年第4期21-25,共5页
[Objective] The paper was to analyze the meteorological epidemic factors for occurrence and prevalence of tobacco bacterial wilt ( Ralstonia solanaca- rum), and to study control effects of different soil conditioner... [Objective] The paper was to analyze the meteorological epidemic factors for occurrence and prevalence of tobacco bacterial wilt ( Ralstonia solanaca- rum), and to study control effects of different soil conditioners on the bacterial disease in Gacligongshan demonstration area of green, ecological, high quality tobac- co leaf production. [Method] The plots attacked by tobacco bacterial wilt over the years were selected and the incidence of the disease was periodically surveyed in tobacco growth period in 2012, 2103 and 2014, respectively. 10 d Effective accumulated temperature and rainfall were counted according to the meteorological data, and the relationship between meteorological factors and disease index was analyzed. The control effects of three kinds of soil conditioners "Zhuanggenfeng", refined fulvic acid and lime on tobacco bacterial wilt were tested. [ Result] The analysis results of meteorological factors showed that 10 d effective accumulated temperature and rainfall were positively correlated to disease index. The variation curve of 10 d effective accumulated temperature and rainfall reflected the change trend of disease index. The pH values were increased by 0.57, 0.50 and 0.72 respectively after applying "Zhuanggenfeng", refined fulvic acid and lime. The aver- age control effects on tobacco bacterial wilt were 60.74% -62. 18%, 53.05% -59.53%, and 48.59% -58.53%, respectively. [ Conclusion] 10 d Effective accumulated temperature and rainfall could be used as important reference for disease forecasting and controUing. The usage of soil conditioner has a certain preven- tion and control effect on tobacco bacterial wilt disease by forming soil conditions conducive to flue-cured tobacco growth but adverse to disease survival, which is an effective auxiliary method against the disease. 展开更多
关键词 Tobacco bacterial wilt (Ralstonia solanacarum) Meteorological factors Soil conditioner Prevention and control
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Impact of Water Deterioration on Growth Indices and Meat Quality of Tilapia zillii and Solea aegyptiaca Fish Inhabiting Lake Qaroun, Egypt
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作者 Khalid H. Zaghloul Sara R. Ramadan +1 位作者 Safaa S. Aljilaney Mohamed A. Helaly 《Natural Resources》 2023年第9期135-148,共14页
The present work studies water deterioration, fish survival and production as a result of effluents discharged directly without prior treatments into lake Qaroun at Fayoum governorate, Egypt. Lake Qaroun represents he... The present work studies water deterioration, fish survival and production as a result of effluents discharged directly without prior treatments into lake Qaroun at Fayoum governorate, Egypt. Lake Qaroun represents heavily polluted wild habitat for both studied fish species, Tilapia zillii and Solea aegyptiaca, the most abundant species. Results revealed deterioration in water quality (low dissolved oxygen but high ammonia, nitrite, copper, lead and cadmium) of Northeastern sector where El-Bats drain discharge its effluents without prior treatment followed by that of eastern sector at four km from the point of El-Bats discharge. Water salinity and dissolved oxygen values were in the following order: Western lake Qaroun sector > Eastern lake Qaroun sector > Northeastern lake Qaroun sector. However, Ammonia and nitrite readings were in the following order: Northeastern sector of Lake Qaroun is followed by the Eastern sector, then the Western sector. Moreover, results of the present field study revealed a decrease in fish production with the lowest condition factor and a deterioration in meat quality (an increase in muscle water content and ash but a decrease total protein and total lipids) in case of fish collected from the polluted sites along the lake (Northeastern and eastern sectors). However, fish collected from the unpolluted western sector of the lake showed condition factor and chemical muscle composition more or less similar to normal healthy fish. 展开更多
关键词 Lake Qaroun T. zillii S. aegyptiaca condition factor Meat Qualit
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城市污泥好氧堆肥研究进展 被引量:2
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作者 台德志 余纪鑫 +1 位作者 黄朝妍 张华 《科技和产业》 2023年第1期222-230,共9页
城市经济的快速发展带来了城市污泥大量增加,无害且资源化地处理城市污泥已经成为新的研究重点。污泥好氧堆肥技术则可以将城市污泥资源化利用,转变为环境友好型产品,符合绿色发展的理念。综述目前主流的城市污泥处理方法,介绍污泥好氧... 城市经济的快速发展带来了城市污泥大量增加,无害且资源化地处理城市污泥已经成为新的研究重点。污泥好氧堆肥技术则可以将城市污泥资源化利用,转变为环境友好型产品,符合绿色发展的理念。综述目前主流的城市污泥处理方法,介绍污泥好氧堆肥常用的活性调理剂和惰性调理剂,列举好氧堆肥的影响因子,总结堆肥腐熟度的判定指标并对好氧堆肥的前景进行展望。 展开更多
关键词 污泥 好氧堆肥 调理剂 影响因子 腐熟度
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矿物源调理剂对南方酸性镉污染水稻农田的修复作用 被引量:3
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作者 林小兵 郭乃嘉 +7 位作者 雷礼文 陈国钧 胡秋萍 万长艳 周琦娜 肖秋云 武琳 周利军 《土壤与作物》 2023年第4期439-447,共9页
为验证土壤调理剂在江西新余酸性镉(Cd)污染稻田上的应用效果,采用田间小区试验,研究了以牡蛎壳、石灰石等为原料的5种矿物源调理剂对土壤Cd、水稻产量及各部位中Cd含量的影响。结果表明:与对照相比,施用矿物源调理剂使土壤pH上升了1.17... 为验证土壤调理剂在江西新余酸性镉(Cd)污染稻田上的应用效果,采用田间小区试验,研究了以牡蛎壳、石灰石等为原料的5种矿物源调理剂对土壤Cd、水稻产量及各部位中Cd含量的影响。结果表明:与对照相比,施用矿物源调理剂使土壤pH上升了1.17~1.69个单位,阳离子交换量增加了13.1%~41.2%;土壤有效态Cd含量降低了0.25%~18.8%;水稻根系、茎秆、叶片、谷壳和糙米中Cd含量分别显著降低了4.81%~48.0%、44.7%~84.9%、38.5%~76.9%、45.8%~79.2%和43.4%~75.5%,水稻产量增加了0.81%~17.9%。水稻不同部位中Cd富集系数表现为:根系>茎杆>叶片>糙米>谷壳,进入水稻体内的Cd主要富集在根系、茎杆和叶片部位。水稻各部位中Cd含量与土壤有效态Cd含量呈极显著正相关关系(P <0.01),而与土壤pH呈极显著负相关关系(P <0.01)。矿物源调理剂通过降低土壤Cd活性,可阻控Cd进入水稻迁移与富集,且能增加水稻产量。 展开更多
关键词 镉污染 矿物源 土壤调理剂 异地验证 富集系数
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多重响应潜力影响因素作用下的变频空调负荷调控方案 被引量:3
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作者 何俊 傅广努 黄海涛 《现代电力》 北大核心 2023年第4期495-504,共10页
变频空调在家用空调中的占比已超过定频空调,成为主流,为指导这部分日益增大的需求响应资源在电力系统中发挥削峰填谷作用,提出变频空调3层调控框架,对变频空调的响应潜力、调度模型和控制策略进行分析研究:在潜力评估层面,基于变频空... 变频空调在家用空调中的占比已超过定频空调,成为主流,为指导这部分日益增大的需求响应资源在电力系统中发挥削峰填谷作用,提出变频空调3层调控框架,对变频空调的响应潜力、调度模型和控制策略进行分析研究:在潜力评估层面,基于变频空调稳态功率获取变频空调负荷聚合功率,考虑用户侧多重影响因素,建立变频空调负荷聚合响应潜力评估模型,获取其聚合响应潜力;在日前调度层,考虑变频空调各时段潜力大小并结合基础柔性负荷响应特性建立联合调度模型,挖掘负荷侧多类型资源参与调节的潜力;在日内控制层,分析变频空调动态、稳态模型,以稳态参数和温变参数为特征属性进行聚类分组,针对变频空调采用温度控制方法进行分组控制,使变频空调负荷跟随调度计划。最后,通过某配电网系统进行验证分析,结论表明:所提3层调控框架对变频空调负荷响应潜力挖掘引导和利用具有一定指导意义。 展开更多
关键词 变频空调 聚合模型 响应潜力 多重因素 分组控制
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带喷雾冷却微通道换热器的传热性能实验研究
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作者 宋霞 王佳威 +1 位作者 施竣业 陈江平 《制冷学报》 CAS CSCD 北大核心 2023年第4期60-67,101,共9页
为研究喷雾冷却对空气侧传热压降性能的影响以及探寻喷雾恰好在微通道换热器表面完全蒸发的具体情况,本文搭建了一套带喷雾冷却的车用风冷型微通道换热器实验台,分析了空气侧在无喷雾状态和带喷雾状态下的传热压降特性。结果表明:无喷... 为研究喷雾冷却对空气侧传热压降性能的影响以及探寻喷雾恰好在微通道换热器表面完全蒸发的具体情况,本文搭建了一套带喷雾冷却的车用风冷型微通道换热器实验台,分析了空气侧在无喷雾状态和带喷雾状态下的传热压降特性。结果表明:无喷雾状态下实验得到的j因子和f因子与经典Chang关联式计算值有较好的吻合度,误差在±10%以内。带喷雾状态下j因子具有明显的提升,但提升效果随喷雾流量的减小和热壁面温度的降低而减弱,总体而言,f因子并未有明显的变化。喷雾流量临界值(恰好完全蒸发)与热壁面温度和风速呈正线性关系,其关联式可拟合得到。以Chang关联式为基础,喷雾状态下的j因子可通过相应的修正因子拟合得到,为喷雾状态下空气侧换热性能的预测提供依据。 展开更多
关键词 车用空调 微通道换热器 喷雾冷却 j因子 f因子
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Determining method,conditional factors,traits and applications of nonlinear chemical fingerprint by using dissipative components in samples 被引量:16
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作者 ZHANG TaiMing ZHAO Zhe +5 位作者 FANG XuanQi QIAO JunXi XIANG FengQin ZHU Rong LIANG YiZeng DING Feng 《Science China Chemistry》 SCIE EI CAS 2012年第2期285-303,共19页
The thermodynamic systems and dynamic model suitable for determining the nonlinear chemical fingerprints of samples were analyzed.The results indicated that the damp nonlinear chemical reactions in close systems away ... The thermodynamic systems and dynamic model suitable for determining the nonlinear chemical fingerprints of samples were analyzed.The results indicated that the damp nonlinear chemical reactions in close systems away from the equilibrium and open systems without the complementarity of the dissipation substances have important significance for the throng characterization and whole content analysis of chemical components in samples.Various factors influencing on nonlinear chemical fingerprint,such as reactant species and their concentrations,electrode types,temperature,stir rate,the sort,dosage and granularity of the sample,etc.were amply researched by a nonlinear chemistry reaction,namely,damp B-Z oscillation which used acetone and glucose as the main dissipative substances.In addition,the quantitative information on the whole of chemical components in samples and the traits and applications of the fingerprint were investigated.The method and its important conditions for determining nonlinear chemistry fingerprint used in distinguishing and evaluating complex samples were successfully put forward. 展开更多
关键词 nonlinear chemical fingerprint dissipative components in samples determining method condition factor authenticityidentification quality evaluation sample
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我国医药物流发展的制约因素及对策分析 被引量:6
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作者 谢明 梁旭 关柏錞 《中国市场》 北大核心 2007年第32期40-41,共2页
在医药行业蓬勃发展的今天,我国医药物流发展相对滞后已成为医药经济快速发展的瓶颈,也是医药行业关注的焦点。本文采用比较分析和归纳的方法,在介绍我国医药物流发展现状的基础上,系统地分析了制约其发展的因素,阐明了我国医药物流发... 在医药行业蓬勃发展的今天,我国医药物流发展相对滞后已成为医药经济快速发展的瓶颈,也是医药行业关注的焦点。本文采用比较分析和归纳的方法,在介绍我国医药物流发展现状的基础上,系统地分析了制约其发展的因素,阐明了我国医药物流发展滞后的原因,并给出了有针对性的对策建议。 展开更多
关键词 医药物流 制约因素 发展
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变频空调中功率因数校正电感的设计 被引量:3
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作者 曾敏 姜立新 江伟 《华南理工大学学报(自然科学版)》 EI CAS CSCD 北大核心 2006年第11期20-24,共5页
介绍了功率因数校正(PFC)电路在变频空调中的应用、优越性和一种输入功率为3.3 kW的变频空调PFC模块的工作原理,对非晶磁性PFC电感的设计进行了详细分析,主要包括:临界电感值的计算、磁性材料的选择及磁芯规格的确定等.试验结果表明,铁... 介绍了功率因数校正(PFC)电路在变频空调中的应用、优越性和一种输入功率为3.3 kW的变频空调PFC模块的工作原理,对非晶磁性PFC电感的设计进行了详细分析,主要包括:临界电感值的计算、磁性材料的选择及磁芯规格的确定等.试验结果表明,铁基非晶磁性材料具有饱和磁通密度高、温度稳定性好的特点,所设计的基于非晶磁性材料的电感能够满足变频空调要求. 展开更多
关键词 变频空调 功率因数校正 电感 非晶材料 变频电源
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