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Control Effects of Tianshifu Soil Conditioners on Cd Contamination in Paddy Fields of Hunan Province 被引量:2
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作者 刘兴元 田发祥 +1 位作者 谢运河 纪雄辉 《Agricultural Science & Technology》 CAS 2015年第7期1447-1451,共5页
To investigate the effects of Tianshifu soil conditioners on rice growth and their control effects on Cd absorption and accumulation in rice, a test was carded out in the field typically polluted by Cd in Hunan Provin... To investigate the effects of Tianshifu soil conditioners on rice growth and their control effects on Cd absorption and accumulation in rice, a test was carded out in the field typically polluted by Cd in Hunan Province. The results showed that the Tianshifu soil conditioner, soil bacterial conditioner and the combination of Tian- shifu soil conditioner and soil bacterial conditioner all could promote rice growth, im- prove rice yield and reduce significantly Cd content in rice grains. In Beishan, the Cd contents in rice grains treated by Tianshifu soil conditioner, soil bacterial condi- tioner and the combination of Tianshifu soil conditioner and soil bacterial conditioner were reduced by 37.63% (P〈0.05), 32.59% (P〈0.05) and 27.95% (P〈0.05) respec- tively compared with that in rice grains treated by conventional fertilization; In Xiang- tan, the Cd contents in rice grains were reduced by 54.36% (P〈0.05), 50.19% (P〈 0.05) and 45.22% (P〈0.05) respectively. The rice grains harvested at the two test sites all met the national food safety standards. Considering the control effect on Cd contamination, Tianshifu soil conditioner 〉 combination of Tianshifu soil condi- tioner and soil bacterial conditioner 〉 Tianshifu soil bacterial conditioner. In addition to reducing Cd absorption in rice, as described in the lime application treatment, the application of Tianshifu soil conditioners also inhibited the transportation of Cd from rice straws to rice grains. The Tianshifu soil conditioner, soil bacterial conditioner and combination of Tianshifu soil conditioner and soil bacterial conditioner also effec- tively improved the soil acidity, increased the soil pH value and reduced soil avail- able Cd content to some extent. 展开更多
关键词 CADMIUM Tianshifu soil conditioners Heavy metals RICE
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Effects of Multiple Soil Conditioners on a Mine Site Acid Sulfate Soil for Vetiver Growth 被引量:6
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作者 LINChu-Xia LONGXin-Xian +3 位作者 XUSong-Jun CHUCheng-Xing MAIShao-Zhi JIANGDian 《Pedosphere》 SCIE CAS CSCD 2004年第3期371-378,共8页
A pot experiment was conducted to investigate the effects of various soil treatments on the growth of vetiver grass ( Vetiveria zizanioides (L.) Nash) with the objective of formulating appropriate soil media for use i... A pot experiment was conducted to investigate the effects of various soil treatments on the growth of vetiver grass ( Vetiveria zizanioides (L.) Nash) with the objective of formulating appropriate soil media for use in sulfide-bearing mined areas. An acidic mine site acid sulfate soil (pH 2.8) was treated with different soil conditioner formula including hydrated lime, red mud (bauxite residues), zeolitic rock powder, biosolids and a compound fertilizer. Soils treated with red mud and hydrated lime corrected soil acidity and reduced or eliminated metal toxicity enabling the establishment of vetiver grass.Although over-liming affected growth, some seedlings of vetiver survived the initial strong alkaline conditions. Addition of appropriate amounts of zeolitic rock powder also enhanced growth, but over-application caused detrimental effects. In this experiment, soil medium with the best growth performance of vetiver was 50 g of red mud, 10 g of lime, 30 g of zeolitic rock powder and 30 g of biosolids with 2000 g of mine soils (100% survival rate with the greatest biomass and number of new shoots), but adding a chemical fertilizer to this media adversely impacted plant growth. In addition, a high application rate of biosolids resulted in poorer growth of vetiver, compared to a moderate application rate. 展开更多
关键词 heavy metals mine site acid sulfate soils soil conditioners soil pH vetiver grass
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CFD-Aided Investigation of Combined Flow Conditioners for Gas Ultrasonic Flow Meter
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作者 袁亚琦 李世阳 +1 位作者 郑佳 李明睿 《Journal of Shanghai Jiaotong university(Science)》 EI 2023年第5期611-620,共10页
Stable and fully developed gas flow field is crucial for realizing accurate measurement of gas ultrasonicflow meter. To reduce the flow field distortion, a flow conditioner is usually used. However, the traditionalmon... Stable and fully developed gas flow field is crucial for realizing accurate measurement of gas ultrasonicflow meter. To reduce the flow field distortion, a flow conditioner is usually used. However, the traditionalmonotype flow conditioner can only improve the flow field distribution partly. The measurement accuracy of thetransit time ultrasonic flow meter is still affected because of its serious flow field distortion in the complex pipelineconditions. In this paper, to further improve the flow field distribution, a combined conditioner is investigated.The combined flow conditioner is composed of fan-shaped section, turbulent mixing cavity, and honeycomb-shapedsection. The effects of fan blade angle and cavity length on the flow field of the DN50 flow meter are studied usingcomputational fluid dynamics (CFD) simulation. Simulation results indicate that compared with the monotypeconditioner, the combined conditioner has better performance on effectively reducing the swirl and turbulence andproviding more stable and repetitive velocity profiles. Experiments also validate the effectiveness of the combinedconditioner. The flow meter with the combined conditioner has better repeatability of less than 0.2%, which isbetter than those of the monotype conditioners under the same conditions. This work is very useful for accuratemeasurement of gas ultrasonic flow meter, especially for the complex pipeline conditions. 展开更多
关键词 computational fluid dynamics(CFD) flow conditioners gas ultrasonic flow meter SWIRL TURBULENCE
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Optimal Scheduling of Air Conditioners for Energy Efficiency
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作者 K.Venkatesan Uppu Ramachandraiah 《Journal of Electronic Science and Technology》 CAS CSCD 2018年第2期110-122,共13页
Energy saving is one of the most important research hotspots, by which operational expenditure and CO2 emission can be reduced. Optimal cooling capacity scheduling in addition to temperature control can improve energy... Energy saving is one of the most important research hotspots, by which operational expenditure and CO2 emission can be reduced. Optimal cooling capacity scheduling in addition to temperature control can improve energy efficiency. The main contribution of this work is modeling the telecommunication building for the fabric cooling load to schedule the operation of air conditioners. The time series data of the fabric cooling load of the building envelope is taken by simulation by using Energy Plus, Building Control Virtual Test Bed (BCVTB), and Matlab. This pre-computed data and other internal thermal loads are used for scheduling in air conditioners. Energy savings obtained for the whole year are about 4% to 6% by simulation and the field study, respectively. 展开更多
关键词 Building fabric cooling load energy balanced air conditioning energy efficiency scheduling of air conditioners
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Evaluation of Energy-Efficiency Standards for Room Air Conditioners in the US
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作者 Alex Lekov Victor Franco Steve Meyers 《Open Journal of Energy Efficiency》 2012年第2期9-20,共12页
This article describes an analysis of the energy and economic impacts of possible energy efficiency standards for room air conditioners on both U.S. consumers and the nation as a whole. We used two metrics to determin... This article describes an analysis of the energy and economic impacts of possible energy efficiency standards for room air conditioners on both U.S. consumers and the nation as a whole. We used two metrics to determine the effect of standards on a representative sample of U.S. consumers: life-cycle cost change and payback period. For the national impact analysis, we evaluated national energy savings attributable to each potential standard, the monetary value of the energy savings to consumers of room air conditioners, the increased total installed costs because of standards, and the net present value of the difference between the value of energy savings and increased total installed costs. Our analysis indicates that standards for room air conditioners at efficiency level 3, which is 17% more efficient than today’s typical unit in the case of room air conditioners less than 6000 Btu/h with louvers and 12% more efficient in the case of room air conditioners 8000 - 13,999 Btu/h with louvers, would save close to one quad of energy over 30 years and have a net present value of consumer benefit of between ?$0.14 billion and $1.82 billion, depending on the discount rate. In addition, such standards would reduce carbon dioxide emissions and NOx emissions. 展开更多
关键词 ENERGY Efficiency STANDARDS Room Air conditioners Consumer Benefit ENERGY SAVINGS LIFE-CYCLE Cost Payback Period Emissions REDUCTIONS
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Window Air Conditioners Transition and Restriction in Saudi Arabia
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作者 Essam Al Ammar Abdulhakim Bin Dayil 《Journal of Power and Energy Engineering》 2022年第5期1-21,共21页
This paper will provide a proposed solution for saving energy consumption due to residential air conditioners by reducing the window air conditioners type which is the most consumed energy and has a big percent of spr... This paper will provide a proposed solution for saving energy consumption due to residential air conditioners by reducing the window air conditioners type which is the most consumed energy and has a big percent of spreading inside KSA than the split type, also it will discuss some restrictions for trading and manufacturing of air conditioner devices inside KSA besides some restrictions on market and buildings to achieve the objective of reducing the consumption of energy which become a big trend in kingdom vision 2030. The results of this suggesting solution will help the decision-makers to start its plan for execution as it has a big difference between using window type from 2022 till 2030 and if we stop its sales and replace by an efficient one of split AC type in energy consumption in addition to CO<sub>2</sub> emission reduction and decreasing of energy cost, hence our kingdom can save petroleum raw materials and keeping the environment to become clean from pollutants so that these resources are delivered to successive generations correct and clean as we received them from those before us. 展开更多
关键词 Air conditioners (AC) Terawatt-Hour (TWh) Saudi Standards Metrology and Quality Organization (SASO) Energy-Efficiency Ratio (EER) High Efficiency Air Conditioning (HEAC) Carbon Dioxide (CO2) Heating Ventilation and Air Conditioning (HVAC) Saudi Building Code (SBC) Saudi Energy Efficiency Center (SEEC)
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Jirong Air Conditioners
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《China's Foreign Trade》 1997年第11期37-37,共1页
Various kinds of cabinet air conditioners,roof top air conditioners, cool-water set of air conditioners, and air treatment apparatuses,produced by Guangdong Jirong Air Conditioner Equipment Corporation, using world na... Various kinds of cabinet air conditioners,roof top air conditioners, cool-water set of air conditioners, and air treatment apparatuses,produced by Guangdong Jirong Air Conditioner Equipment Corporation, using world namebrand compressors, blower fans, computers,and control devices and other materials imported from abroad, are widely used in industrial and civil projects. The quality of the products is reliable, with low noise, easy operation, and high precision for control. Their main quotas for specifications are up to the international advanced standards. The output of Jirong cabinet and roof-top air conditioners is the leader in the country. The variety of cabinet conditioners includes water-cool and air-coon ones 展开更多
关键词 Jirong Air conditioners
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Three National Compulsory Standards on Energy Efficiency of Air Conditioners Approved
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《China Standardization》 2004年第6期12-13,共2页
关键词 Three National Compulsory Standards on Energy Efficiency of Air conditioners Approved
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Effects of conditioners(single-layer, double-layer and retentionconditioner) on the growth performance, meat quality and intestinal morphology of growing and finishing pigs 被引量:2
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作者 DUAN Hai-tao LI Jun-guo +4 位作者 XUE Min YANG Jie DONG Ying-chao LIANG Ke-hong QIN Yu-chang 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2018年第4期919-927,共9页
This experiment was conducted to investigate the effects of feed conditioners(single-layer, double-layer and retentionconditioner) on the growth performance, meat quality and intestinal morphology of pigs throughout t... This experiment was conducted to investigate the effects of feed conditioners(single-layer, double-layer and retentionconditioner) on the growth performance, meat quality and intestinal morphology of pigs throughout the growing to finishing phase. A total of 96 growing pigs((28.70±3.20) kg) were selected and randomized into three treatment groups with four replicates per group. Eight pigs were used per replicate for the 17-week feeding trial. The grower diet was given at 0 to 6 weeks and a finisher diet was given at 6 to 17 weeks. The treatments were as follows: SC diet(control; single-layer conditioning), DC diet(double-layer conditioning), and RC diet(retention-conditioning). Starch gelatinization was significantly higher(P<0.05) in the RC treatment than in the SC treatment, however, there was no significant difference in the starch gelatinization between the DC group and the RC group. In the growing phase, the feed to gain index(F:G) was significantly lower(P<0.05) in the RC group than in the SC and DC groups. Between growing and finishing, the F:G was the lowest(P<0.05) in the SC group compared to the RC or DC group. Drip loss, a measurement of meat quality, was significantly lower(P<0.05) in longissimus dorsi tissue collected from pigs fed the RC diet than in tissues collected from pigs fed the SC diet. The intestinal quality of the duodenum and jejunum tissues showed a significant increase(P<0.05) in the crypt depth and villus height in the RC group compared to the SC-or DC-treated pigs. These results demonstrated that the retentionconditioner treatment decreased the F:G in growing pigs, improved intestinal morphology and enhanced the meat quality in the finishing pigs. However, the retention-conditioner treatment had a negative impact on growth performance in the finishing pigs. 展开更多
关键词 PIGS CONDITIONER feed quality meat quality intestinal morphology
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Soil conditioners improve Cd-contaminated farmland soil microbial communities to inhibit Cd accumulation in rice 被引量:2
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作者 ZHAO Jun-yang LU Hua-ming +8 位作者 QIN Shu-tao PAN Peng TANG Shi-de CHEN Li-hong WANG Xue-li TANG Fang-yu TAN Zheng-long WEN Rong-hui HE Bing 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2023年第8期2521-2535,共15页
The addition of silicon(Si)and organic fertilizers to soil conditioners can inhibit the transfer of heavy metal ions from soil to crops.However,it is not clear how Si and organic fertilizers affect soil properties and... The addition of silicon(Si)and organic fertilizers to soil conditioners can inhibit the transfer of heavy metal ions from soil to crops.However,it is not clear how Si and organic fertilizers affect soil properties and the micro-ecological environment and thereby reduce cadmium(Cd)accumulation in rice.In this study,the effects of L-type soil conditioners containing Si and organic fertilizers on bacterial and fungal community diversity,soil pH,organic matter,and available Si were analyzed with field experiments at two sites in Liuzhou City and Hezhou City,respectively,in Guangxi,China.With the increase of Si and organic fertilizer content in soil conditioner,rice yield respectively increased by 16.8–25.8 and 6.8–13.1%,and rice Cd content decreased significantly by 8.2–21.1 and 10.8–40.6%,respectively,at the two experimental sites.Soil microbiome analysis showed that the increase in abundance of Firmicutes and Actinobacteriota bacteria associated with Cd adsorption and sequestration,and Basidiomycota fungal populations associated with degradation of macromolecules favored the inhibition of soil Cd activity(soil exchangeable Cd decreased by 14.4–14.8 and 18.1–20.6%).This was associated with an increase in organic matter and Si content caused by applying soil conditioners.In conclusion,L-type soil conditioners,rich in Si and organic fertilizer,can reduce soil Cd bioavailability by regulating the dominant Cd passivating flora in the soil and ultimately reduce Cd accumulation in rice. 展开更多
关键词 soil conditioner SILICON organic matter microbial community Cd accumulation in rice
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A PROSPECTIVE HYDROGEN STORAGE ALLOY PAIR FOR BUS AIR CONDITIONERS 被引量:1
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作者 Wang Xinhua and Chen Changpin Department of Materials Science and Engineering,Zhejiang University, Hangzhou 310027, P. R. China 《中国有色金属学会会刊:英文版》 CSCD 1998年第1期57-60,共4页
APROSPECTIVEHYDROGENSTORAGEALLOYPAIRFORBUSAIRCONDITIONERS①WangXinhuaandChenChangpinDepartmentofMaterialsScie... APROSPECTIVEHYDROGENSTORAGEALLOYPAIRFORBUSAIRCONDITIONERS①WangXinhuaandChenChangpinDepartmentofMaterialsScienceandEnginering,... 展开更多
关键词 hydride HYDROGEN STORAGE ALLOY BUS heat pump AIR CONDITIONER
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Remediation Effects of Soil Conditioners for CdPolluted Paddy Fields 被引量:1
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作者 XIE Yun-he HUANG Bo-jun +3 位作者 JI Xiong-hui TIAN Fa-xiang WU Jia-mei GUAN Di 《Agricultural Science & Technology》 CAS 2019年第3期31-38,共8页
A field experiment was conducted to evaluate the remediation effects of 14 soil conditioners for Cd-polluted paddy fields contrasted with conventional fertilization and liming.The results showed that soil conditioners... A field experiment was conducted to evaluate the remediation effects of 14 soil conditioners for Cd-polluted paddy fields contrasted with conventional fertilization and liming.The results showed that soil conditioners had no significant impact on rice yields.Though the soil conditioners had stable effects on decreasing the Cd content in grains,the effects varied with the category of conditioners.In general,The Cd contents of early rice and late rice were reduced by 22.65%~44.24%and 15.20%~63.03%,respectively.Additionally,the stem and leaves showed the same decreasing tendency.Cluster analysis suggested that soil conditioners can be divided into three categories:the first category increases the soil pH to inhibit the Cd activity and cut down the Cd translocation from soil to stem and leaves,which is most efficient in the reduction of Cd content in rice grains;the other category relies on the antagonism or co-precipitation between Cd and certain elements to inhibit the translocation and redistribution of Cd from rice stems to grains,providing a common effect on Cd reduction;the last category can be seen as a combination of the former two categories from the perspective of its functional mechanism and it has a moderate effect on the reduction of Cd contents in rice grains. 展开更多
关键词 Soil conditioner Cd-contaminated Paddy soil Effectiveness evaluation Heavy metal
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A Comparative Study on the Performance and Environmental Characteristics of Alternatives to R22 in Residential Air Conditioners for Tunisian Market 被引量:1
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作者 M.C. Zaghdoudi S. Maalej +1 位作者 Y. Saad M. Bouchaala 《Journal of Environmental Science and Engineering》 2010年第12期37-56,共20页
This paper presents the simulation results of a 9000 BTU/h air conditioner with some selected fluids that have been assessed for their suitability as alternatives to R22 for air conditioners. Only those refrigerants w... This paper presents the simulation results of a 9000 BTU/h air conditioner with some selected fluids that have been assessed for their suitability as alternatives to R22 for air conditioners. Only those refrigerants with zero Ozone Depletion Potential (ODP) are considered. The performances of 11 refrigerants were comparatively studied using the simulation software NIST Cycle_D. R134a, R290, R600, R404A, R407A, R407B, R407C, 407D, R410A, R410B, and R417A are considered in this study. The thermal performances, which are obtained with R 134a and R290, are very close to those of R22. The power consumptions of the unit operating with R404A, R407C, and R410A are higher in the range 22-31% with respect of R22. For the units operating with 407A, R407B, R407D, R407E, and R410B, the electric consumptions are higher in the range 10-23%. For R600, the power consumptions are in the range 6-8%. For all the fluids, the COP is lower by 7-24% than R22, except for R600 for which the COP is higher by 7-9%, and R134a and R290 which exhibit the same COP as R22. When considering the thermal and environmental parameters, R290 is identified as the best candidate for R22, provided the safety aspects of using R290 are addressed. 展开更多
关键词 Air conditioner REFRIGERANT REPLACEMENT simulation PERFORMANCE COP
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DOMAIN DECOMPOSITION PRECONDITIONERS FOR SECOND-ORDER HYPERBOLIC EQUATIONS ON L-SHAPED REGIONS
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作者 金小庆 王朝光 《Numerical Mathematics A Journal of Chinese Universities(English Series)》 SCIE 1995年第1期54-62,共9页
Linear systems arising from implicit time discretizations and finite difference space discretizations of second-order hyperbolic equations on L-shaped region are considered. We analyse the use of domain deocmposilion ... Linear systems arising from implicit time discretizations and finite difference space discretizations of second-order hyperbolic equations on L-shaped region are considered. We analyse the use of domain deocmposilion preconditioner.s for the solution of linear systems via the preconditioned conjugate gradient method. For the constant-coefficient second-order hyperbolic equaions with initial and Dirichlet boundary conditions,we prove that the conditionnumber of the preconditioned interface system is bounded by 2+x2 2+0.46x2 where x is the quo-tient between the lime and space steps. Such condition number produces a convergence rale that is independent of gridsize and aspect ratios. The results could be extended to parabolic equations. 展开更多
关键词 Domain decomposition hyperbolie equation CAPACITANCE matrix condition number preconditioned CONJUGATE gradient method
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SINE TRANSFORM PRECONDITIONERS FOR SECOND-ORDER PARTIAL DIFFERENTIAL EQUATIONS
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作者 金小庆 《Numerical Mathematics A Journal of Chinese Universities(English Series)》 SCIE 1993年第1期116-123,共8页
In this paper, we are concerned with the numerical solution of second-order partial differential equations. We analyse the use of the Sine Transform precondilioners for the solution of linear systems arising from the ... In this paper, we are concerned with the numerical solution of second-order partial differential equations. We analyse the use of the Sine Transform precondilioners for the solution of linear systems arising from the discretization of p.d.e. via the preconditioned conjugate gradient method. For the second-order partial differential equations with Dirichlel boundary conditions, we prove that the condition number of the preconditioned system is O(1) while the condition number of the original system is O(m 2) Here m is the number of interior gridpoints in each direction. Such condition number produces a linear convergence rale. 展开更多
关键词 SINE TRANSFORM finite difference METHOD SECOND-ORDER partial differential equation condition number preconditioned conjugate gradient METHOD
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Advances in Research on Effect of Heavy Metals Cd and Pb on Wheat and Mitigation Effect of Conditioners
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作者 Shuyan SONG Hao LIU Belekz·Matikurban 《Asian Agricultural Research》 2021年第4期31-33,共3页
In this article,the effect of heavy metals Cd and Pb on seed germination,seedling growth and yield of wheat is investigated,and the effect of related conditioners on improving soil and alleviating Cd and Pb stress is ... In this article,the effect of heavy metals Cd and Pb on seed germination,seedling growth and yield of wheat is investigated,and the effect of related conditioners on improving soil and alleviating Cd and Pb stress is explored. 展开更多
关键词 WHEAT Heavy metal stress CD PB CONDITIONER
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Cross-city insights on sustainable consumption:consistency and disparities in willingness to buy and pay for green air conditioners
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作者 Jiachao Ke Shujie Zhao +3 位作者 Yaozhong Guo Qingbin Song Ni Sheng Jinhui Li 《Frontiers of Environmental Science & Engineering》 2025年第4期169-185,共17页
The intensification of climate change action has made air conditioners a key target for emission reductions.This study examines the factors influencing residents’willingness to buy(WTB)and willingness to pay(WTP)for ... The intensification of climate change action has made air conditioners a key target for emission reductions.This study examines the factors influencing residents’willingness to buy(WTB)and willingness to pay(WTP)for green air conditioners across six cities in the Pearl River Delta(PRD)region,aiming to understand consumer behavior and inform targeted market strategies.Using a novel Contingent Valuation Method(CVM),this study surveyed 1732 residents through online and face-to-face interviews.Binary logistic and ordered logistic regression analyses identified key factors affecting WTB and WTP,including gender,income,education,knowledge of green air conditioners,and confidence in their emission reduction potential.However,the study reveals significant regional disparities in WTP and payment amounts through the Kruskal-Wallis H and Mann-Whitney U tests.The results also highlight Shenzhen has significant difference and highest payment value than other cities.These findings provide valuable insights into regional disparities and common factors in green consumption,offering guidance for market strategies and policy development aimed at promoting green air conditioners. 展开更多
关键词 Contingent valuation method Green air conditioners WTB and WTP Influence factors Consistency and difference
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McKean-Vlasov Backward Stochastic Differential Equations with Weak Monotonicity Coefficients
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作者 FU Zongkui FEI Dandan GUO Shanshan 《应用数学》 北大核心 2026年第1期98-107,共10页
This paper deals with Mckean-Vlasov backward stochastic differential equations with weak monotonicity coefficients.We first establish the existence and uniqueness of solutions to Mckean-Vlasov backward stochastic diff... This paper deals with Mckean-Vlasov backward stochastic differential equations with weak monotonicity coefficients.We first establish the existence and uniqueness of solutions to Mckean-Vlasov backward stochastic differential equations.Then we obtain a comparison theorem in one-dimensional situation. 展开更多
关键词 McKean-Vlasov backward stochastic differential equation Weak monotonicity condition Comparison theorem
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Redundant source-wavelet amplitude influence in wave-equation migration/demigration flow and its removal
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作者 QianCheng Liu JiaLe Kang Jie Li 《Earth and Planetary Physics》 2026年第1期75-81,共7页
In wave-equation migration and demigration,the cross-correlation imaging/forwarding step implicitly injects an additional copy of the source wavelet,so that the amplitude spectrum of the wavelet is applied redundantly... In wave-equation migration and demigration,the cross-correlation imaging/forwarding step implicitly injects an additional copy of the source wavelet,so that the amplitude spectrum of the wavelet is applied redundantly(effectively imposing a wavelet-spectrum weighting,often akin to an amplitude-squared bias).This redundancy degrades structural fidelity and amplitude balance yet is frequently overlooked.We(i)formalize the mechanism by which cross-correlation duplicates the source-wavelet amplitude effect in both migration and demigration,and(ii)introduce a source-equalized operator that removes the redundancy by deconvolving(or dividing by)the wavelet amplitude spectrum in the imaging condition and its demigration counterpart,while leaving phase/kinematics intact.Using a band-limited Ricker wavelet on a two-layer model and on Marmousi,we show that,if unmanaged,the redundant wavelet spectrum broadens main lobes,introduces ringing,and suppresses vertical resolution in migrated images,and inflates spectrum mismatches between demigrated and observed data even when peak times agree.With our correction,images recover observed-data-consistent bandwidth and sharpened interfaces,and demigrated data also exhibit improved spectrum conformity and reduced amplitude misfit.The results clarify when source amplitudes matter,why cross-correlation makes them redundantly matter,and how a lightweight spectral correction restores physically meaningful amplitude behavior in wave-equation migration/demigration. 展开更多
关键词 wave-equation migration DEMIGRATION cross-correlation imaging condition source wavelet amplitude spectrum spectral deconvolution
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ON BLOCK PRECONDITIONERS FOR PDE-CONSTRAINED OPTIMIZATION PROBLEMS 被引量:1
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作者 Xiaoying Zhang Yumei Huang 《Journal of Computational Mathematics》 SCIE CSCD 2014年第3期272-283,共12页
Recently, Bal proposed a block-counter-diagonal and a block-counter-triangular precon- ditioning matrices to precondition the GMRES method for solving the structured system of linear equations arising from the Galerki... Recently, Bal proposed a block-counter-diagonal and a block-counter-triangular precon- ditioning matrices to precondition the GMRES method for solving the structured system of linear equations arising from the Galerkin finite-element discretizations of the distributed control problems in (Computing 91 (2011) 379-395). He analyzed the spectral properties and derived explicit expressions of the eigenvalues and eigenvectors of the preconditioned matrices. By applying the special structures and properties of the eigenvector matrices of the preconditioned matrices, we derive upper bounds for the 2-norm condition numbers of the eigenvector matrices and give asymptotic convergence factors of the preconditioned GMRES methods with the block-counter-diagonal and the block-counter-triangular pre- conditioners. Experimental results show that the convergence analyses match well with the numerical results. 展开更多
关键词 PDE-constrained optimization GMRES method PRECONDITIONER Condition number Asymptotic convergence factor.
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