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Current Status and Development Countermeasures of Forest Land Resources in Southern Cixi City
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作者 Congling FANG Hefeng ZHOU +1 位作者 Shaoqing XU Guangru CHAI 《Asian Agricultural Research》 2020年第2期11-13,16,共4页
Based on the investigation of the status of forest land resources in the southern parts of Cixi City,the problems exiting in the development of forestry(e.g.overdevelopment of industry and decline in water conservatio... Based on the investigation of the status of forest land resources in the southern parts of Cixi City,the problems exiting in the development of forestry(e.g.overdevelopment of industry and decline in water conservation quality)are pointed out,and countermeasures(e.g.coordination,integration,scientific planning,strict protection,orderly development and ecological compensation)are put forward,in order to provide a reference for the sustainable development of forestry in Cixi City. 展开更多
关键词 FOREST land resource Status COUNTERMEASURE CIXI CITY
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Nail Holding Performance of Self-Tapping Screws on Masson Pine and Chinese Fir Dimension Lumbers
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作者 De Li Bengang Zhang +7 位作者 Yuan Tu Guoming Xiao Meifen Tian Xiaoxue Xu Xiao Zhong Qiaoyan Zhang Zhigang Wu Jiankun Liang 《Journal of Renewable Materials》 EI 2023年第10期3725-3738,共14页
Screw connection is a type most commonly applied to timber structures.As important commercial tree species in China,Masson pine and Chinese fir have the potential to prepare wood structures.In this study,the effects o... Screw connection is a type most commonly applied to timber structures.As important commercial tree species in China,Masson pine and Chinese fir have the potential to prepare wood structures.In this study,the effects of the diameter of the self-tapping screw and the guiding bores on the nail holding performance on different sections of Masson pine and Chinese fir dimension lumbers were mainly explored.The results showed that:(1)The nail holding strength of the tangential section was the maximum,followed by that of the radial section,and that of the cross section was the minimum.(2)The nail holding strength of Masson pine was higher than that of Chinese fir.(3)The nail holding strength grew with the increase in the diameter of self-tapping screws,but a large diameter would lead to plastic cracking of the timber,thus further affecting the nail holding strength.Masson pine and Chinese fir reached the maximum nail holding strength when the diameter of self-tapping screws was 3.5 mm.(4)Under a large diameter of screws,prefabricated guiding bores could mitigate timber cracking and improve its nail holding strength.(5)Prefabricated guiding bores were more necessary for the screw connection of Masson pine.The results obtained could provide a scientific basis for the screw connection design of Masson pine and Chinese fir timber structures. 展开更多
关键词 Masson pine Chinese fir self-tapping screws nail holding performance
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Micro-reconstruction Strategies of Urban Villages in Small Towns from the Perspective of Policy Orientation:A Case Study of Zhuangqian Xiongjia Village,Fengcheng City
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作者 WU Na FAN Qindan 《Journal of Landscape Research》 2023年第4期41-44,49,共5页
As China’s economy shifts from high-speed development to high-quality development,China’s urbanization also shifts from incremental expansion to stock optimization,providing a new direction for the transformation of... As China’s economy shifts from high-speed development to high-quality development,China’s urbanization also shifts from incremental expansion to stock optimization,providing a new direction for the transformation of urban villages.At present,the reconstruction work office of urban villages in small towns is mainly promoted based on government-led and villager main body in the initial exploration stage.From the perspective of policy orientation,to solve the main problems in urban villages in small towns,Zhuangqian Xiongjia Village,Fengcheng City was taken as an example,and the micro-transformation strategies of urban villages were put forward from the perspective of satisfying the appeals of the government,village committee and villagers,so as to provide some references for the transformation of urban villages in other small towns across the country. 展开更多
关键词 Policy orientation Urban village in a small town Micro-transformation strategies
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Spatio-temporal Variation of Water Heat Flux Using MODIS Land Surface Temperature Product over Hulun Lake,China During 2001–2018
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作者 ZHAO Boyu DU Jia +6 位作者 SONG Kaishan Pierre-Andre JACINTHE XIANG Xiaoyun ZHOU Haohao YANG Zhichao ZHANG Liyan GUO Pingping 《Chinese Geographical Science》 SCIE CSCD 2020年第6期1065-1080,共16页
Heat flux is important for studying interactions between atmosphere and lake.The heat exchange between air-water interfaces is one of the important ways to govern the temperature of the water surface.Heat exchange bet... Heat flux is important for studying interactions between atmosphere and lake.The heat exchange between air-water interfaces is one of the important ways to govern the temperature of the water surface.Heat exchange between the air-water interfaces and the surrounding environment is completed by solar radiation,conduction,and evaporation,and all these processes mainly occur at the air-water interface.Hulun Lake was the biggest lake which is also an important link and an indispensable part of the water cycle in Northeast China.This study mapped surface energy budget to better understand spatial and temporal variations in Hulun Lake in China from 2001 to 2018.Descriptive statistics were computed to build a historical time series of mean monthly heat flux at daytime and nighttime from June to September during 2001–2018.Remote sensing estimation methods we used was suitable for Hulun Lake(R2=0.81).At month scale,shortwave radiation and latent heat flux were decrease from June to September.However,the maximum sensible heat flux appeared in September.Net longwave radiation was the largest in August.The effective heat budget showed that Hulun Lake gained heat in the frost-free season with highest value in June(686.31 W/m2),and then steadily decreased to September(439.76 W/m2).At annual scale,net longwave radiation,sensible heat flux and latent heat flux all show significant growth trend from 2001 to 2018(P<0.01).Wind speed had the well correlation on sensible heat flux and latent heat flux.Water surface temperature showed the highest coefficient in sensitivity analysis. 展开更多
关键词 water surface temperature(WST) heat flux Moderate Resolution Imaging Spectroradiometer(MODIS) remote sensing Hulun Lake China
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Characteristics and sources of ore-forming fluids of South Narimalahei copper polymetallic deposit in East Kunlun,Qinghai
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作者 SUN Qu WANG Li +5 位作者 ZHANG Yongsheng FAN Xingzhu ZHANG Guofeng SHENG Jianhua CHEN Xiaohang LIU Xiang 《Global Geology》 2021年第3期144-153,共10页
The South Narimalahei area is located on the north side of the Middle Kunlun fault in the eastern section of the East Kunlun composite orogenic belt. The ore body is veined and controlled by structures and se- condary... The South Narimalahei area is located on the north side of the Middle Kunlun fault in the eastern section of the East Kunlun composite orogenic belt. The ore body is veined and controlled by structures and se- condary fissures, which occurs in the structural alteration fracture zone in the Late Triassic granodiorite. In this deposit, copper mineralization is closely related to silicification and sericification. The formation process of the deposit includes hydrothermal mineralization and supergene oxidation. In this paper, the fluid inclusion minera- logy , microscopic temperature measurement and stable isotope studies have been carried out for ore of the main mineralization stage. The results show that the primary gas-liquid two-phase inclusions and a small amount of single-liquid inclusions are mainly developed in the quartz in the main mineralization stage. The results of microscopic temperature measurement show that the ore-forming fluid which has low temperature (151.7℃ -205.8 ℃), low salinity(2.06wt% - 4.94wt%NaCl), low density (0.86 -0.92 g/cm^( 3)) and shallow formation (1.5 -3.0 km) is a hydrothermal solution of NaCl-H_(2)O system. Hydrogen and oxygen isotope results show that the ore-forming fluids mainly come from atmospheric precipitation, with a small amount of magmatic fluids participating. It is preliminarily determined that the South Narimalahei copper polymetallic deposit is a low- temperature hydrothermal vein deposit. 展开更多
关键词 copper polymetallic deposit fluid inclusions South Narimalahei East Kunlun
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High-frequency compensation for seismic data based on adaptive generalized S transform 被引量:2
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作者 Li Hui-Feng Wang Jin +1 位作者 Wei Zheng-Rong Yang Fei-Long 《Applied Geophysics》 SCIE CSCD 2020年第5期747-755,902,共10页
The low-pass fi ltering eff ect of the Earth results in the absorption and attenuation of the high-frequency components of seismic signals by the stratum during propagation.Hence,seismic data have low resolution.Consi... The low-pass fi ltering eff ect of the Earth results in the absorption and attenuation of the high-frequency components of seismic signals by the stratum during propagation.Hence,seismic data have low resolution.Considering the limitations of traditional high-frequency compensation methods,this paper presents a new method based on adaptive generalized S transform.This method is based on the study of frequency spectrum attenuation law of seismic signals,and the Gauss window function of adaptive generalized S transform is used to fi t the attenuation trend of seismic signals to seek the optimal Gauss window function.The amplitude spectrum compensation function constructed using the optimal Gauss window function is used to modify the time-frequency spectrum of the adaptive generalized S transform of seismic signals and reconstruct seismic signals to compensate for high-frequency attenuation.Practical data processing results show that the method can compensate for the high-frequency components that are absorbed and attenuated by the stratum,thereby eff ectively improving the resolution and quality of seismic data. 展开更多
关键词 seismic data time-frequency analysis adaptive generalized S transform high-frequency compensation
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Investigation Flow Depth and Flow Speed Changes in the Karun River
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作者 Mehrab Yusefi Hagivar Mehdi Behdarvandi Askar Shariat Moalemi 《Open Journal of Marine Science》 2017年第2期289-299,共11页
In the present study, the Karun River in Khuzestan province in Iran is that is somehow considered the river with the most water in the country was examined. To examine the depth and speed of the flow, which undoubtedl... In the present study, the Karun River in Khuzestan province in Iran is that is somehow considered the river with the most water in the country was examined. To examine the depth and speed of the flow, which undoubtedly have the greatest impact on the environment and ecosystem of the river, two-dimensional simulation by CCHE2D model was used. In this study, it was observed that, firstly, the changes of depth and velocity along the river have good coordination and the highest changes were observed in the meander and arches. Moreover, due to using two-dimensional model, there is the possibility of examining changes of parameters in the longitudinal and transverse direction that shows the two-dimensional model is an efficient and powerful model in studying river flows. 展开更多
关键词 DEPTH CHANGES SPEED CHANGES the Karun RIVER CCHE2D
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Improving Soil Fertility with Different Planting Patterns in Rocky Desertification Areas
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作者 Fang QIN Lirong SU +8 位作者 Chengcheng ZENG Qin LI Tieguang HE Yuefeng YU Nan WEI Yuanqing MENG Aina WEI Jinshan WEI Daizu XIE 《Agricultural Biotechnology》 CAS 2020年第6期119-124,共6页
[Objectives]This study was conducted to investigate the effect of different planting patterns on soil improvement in rocky desertification areas.[Methods]The one-way ANOVA analysis method was used to statistically ana... [Objectives]This study was conducted to investigate the effect of different planting patterns on soil improvement in rocky desertification areas.[Methods]The one-way ANOVA analysis method was used to statistically analyze the soil physical and chemical properties,enzyme activity,microbial quantity,CEC,ECEC,and aggregate content distribution with different planting patterns.[Results]The walnut+sesame+mung bean planting pattern showed the highest soil available phosphorus,available potassium,porosity,non-capillary porosity,and contents of free living nitrogen-fixing bacteria,organophosphate-dissolving bacteria,bacteria,fungi and actinomycetes,at 63.2 mg/kg,178.8 mg/kg,22.85%,6.89%,10.0×10^6 bacteria/g,18.0×10^6 bacteria/g,21.0×10^5 CFU/g,5.7×10^3 CFU/g and 7.9×10^5 CFU/g,respectively,and it reduced soil bulk density(the same as treatment F and treatment E)compared with other planting patterns.The walnut+American chicory+sweet potato planting pattern had the highest alkali-hydrolyzale nitrogen,organic matter,CEC,ECEC,water-air ratio and moisture content,which were 227.9 mg/kg,46.30 g/kg,36.38 cmol/kg,24.00 cmol/kg,8.13,and 32.89%,respectively,and it reduced soil bulk density,increased capillary porosity,acid phosphatase,and contents of bacteria and actinomycetes compared with single cropping of walnut.[Conclusions]Interplanting crops under walnut forests is an effective measure to improve the ecological environment of rocky desertification farmland. 展开更多
关键词 Stony desertification Planting pattern Soil fertility
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Evaluation of freeze-thaw erosion in Tibet based on the cloud model 被引量:1
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作者 Junfu FAN Taoying HU +3 位作者 Xiao YU Jiahao CHEN Liusheng HAN Yuke ZHOU 《Frontiers of Earth Science》 SCIE CSCD 2021年第3期495-506,共12页
Freeze-thaw erosion can lead to accelerated soil loss,which is an important factor related to soil erosion in cold regions.Tibet is a typical region that is seriously affected by freeze-thaw erosion.Traditionally,the ... Freeze-thaw erosion can lead to accelerated soil loss,which is an important factor related to soil erosion in cold regions.Tibet is a typical region that is seriously affected by freeze-thaw erosion.Traditionally,the analytic hierarchy process(AHP)method is used to calculate the weight of the factors in evaluations of freeze-thaw erosion,but this method cannot accurately depict the fuzziness and randomness of the problem.To overcome this disadvantage,this study proposed an improved AHP method based on the cloud model for the evaluation of the factors impacting freeze-thaw erosion.To establish an improved evaluation method for freeze-thaw erosion in Tibet,the following six factors were selected:mean annual air temperature,mean annual ground surface temperature,average annual precipitation,aspect,vegetation coverage,and topographic relief.The traditional AHP and the cloud model were combined to assign the weights of the impacting factors,and a consistency check was performed.The comprehensive evaluation index model was used to evaluate the intensity of freeze-thaw erosion in Tibet.The results show that freeze-thaw erosion is extensive,stretching over approximately 66.1%of Tibet.Moreover,mild erosion and moderate erosion are the most widely distributed erosion intensity levels,accounting for 36.4%and 34.4%of the total freeze-thaw erosion,respectively.The intensity of freeze-thaw erosion gradually increased from slight erosion in the northwest to severe erosion in the southeast of the study region.The evaluation results for the intensity and distribution of freeze-thaw erosion in Tibet were confirmed to be consistent with the actual situation.In brief,this study supplies a new approach for quantitatively evaluating the intensity of freeze-thaw erosion in Tibet. 展开更多
关键词 freeze-thaw erosion cloud model AHP TIBET
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Dramatic Impact of Auxiliary Ligands on the Dynamic Magnetic Relaxation in Tetranuclear Dy^(III)_(2)Zn^(II)_(2) Single Molecule Magnets 被引量:1
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作者 Gao-Peng Li Hong-Fang Xie +3 位作者 Shi-Rui Yang Yun-Long Fu Yi-Quan Zhang Yao-Yu Wang 《Chinese Journal of Chemistry》 SCIE CAS CSCD 2022年第20期2415-2420,共6页
Better understanding the determining factors of dynamic magnetic relaxation in polynuclear lanthanide based single-molecule magnets(SMMs)remains a challenge due to the complexity of such architectures involving intera... Better understanding the determining factors of dynamic magnetic relaxation in polynuclear lanthanide based single-molecule magnets(SMMs)remains a challenge due to the complexity of such architectures involving interactions between the magnetic centers.To address this issue,two structurally related heterometal Dy^(III)_(2)Zn^(II)_(2) SMMs,[Zn_(2)Dy_(2)(L)_(4)(Ac)_(2)(DMF)(CH_(3)OH)]·CH_(3)OH·2H_(2)O(1)and[Zn_(2)Dy_(2)(L)_(4)(Ac)_(2)(DMF)_(2)]·4CH_(3)CN(2)(H_(2)L=(E)-2-((2-hydroxy-3-methoxybenzylidene)amino)-4-methyphenol,DMF=N,N-dimethylformamide),are introduced and investigated.Through modifying the auxiliary ligands on one Dy^(III) site while retaining that on the other Dy^(III),the intramolecular magnetic interactions and relaxation dynamics in these two heterometallic-Dy^(III)_(2)Zn^(II)_(2) SMMs can be tuned,demonstrating a dramatic change in the magnet relaxation behavior with energy barrier changing from a negligible value for 1 to 305 K for 2.Ab initio calculations reveal that changing the coordination geometries on the Dy^(III) sites can significantly affect the magnetic interactions as well as single-ion anisotropy. 展开更多
关键词 Single-molecule magnets Dynamic magnetic relaxation DYSPROSIUM Auxiliary ligands Ab initio calculations
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