期刊文献+
共找到95篇文章
< 1 2 5 >
每页显示 20 50 100
Physi-Chemical Property Research of Polysaccharides from Pomegranate Flowers 被引量:1
1
作者 Lixin Peng Yizhao Huang +2 位作者 Wei Tan Zhiwei Wei Lihua Zhang 《Agricultural Sciences》 2021年第2期59-67,共9页
<div style="text-align:justify;"> Pomegranate flowers as row materials were used for extraction of polysaccharides by water-extraction and alcohol-precipitation method. After purification, the physical... <div style="text-align:justify;"> Pomegranate flowers as row materials were used for extraction of polysaccharides by water-extraction and alcohol-precipitation method. After purification, the physical and chemical properties, structure, monosaccharide composition and molecular weight were studied. The results showed that the polysaccharides from pomegranate flowers mainly contained two kinds of water soluble acidic polysaccharides, and monosaccharide composition were arabinose and galactose, both contained hydroxyl, carboxyl, amino, hydroxyl radical, sulfate, beta glycosidic bond and alpha glycosidic bond structure. The molecular weight of PP1 and PP2 were 6.16 × 104 (±6.6%) and 9.01 × 104 (±3.2%), respectively. The results of this study laid the foundation for further development and application of polysaccharides from pomegranate flowers. </div> 展开更多
关键词 POLYSACCHARIDES Pomegranate Flowers Physical and chemical Properties
下载PDF
GIS-Based Assessment of Soil Chemical and Physical Properties as a Basis for Land Reclamation in Toshka Area, Aswan, EGYPT
2
作者 Ahmed A. M. Awad Mostafa M. A. Al-Soghir 《Open Journal of Geology》 2023年第7期697-719,共23页
The accurate assessment of soil properties is a crucial factor for composing and implementing reclamation plans. The main objective of this study was to evaluate soil chemical and physical properties and calculate the... The accurate assessment of soil properties is a crucial factor for composing and implementing reclamation plans. The main objective of this study was to evaluate soil chemical and physical properties and calculate the chemical and fertility index for assisting land reclamation in Toshka area. The Toshka area is located between latitudes 31°32'N and 31°36'N and longitudes 32°40'E and 32°60'E. GIS was used to select 16 sites. The results revealed the soil has undesirable characteristics. The soil pH ranged from slightly alkaline to moderately alkaline. Furthermore, it was characterized as saline (with a ECe of 4.65 - 11.45 dS⋅m<sup>−1</sup>) and moderately calcareous soil (with CaCO<sub>3</sub> at 11.85% - 17.20%). The soil had a low soil organic matter content which did not exceed 0.18%. The soil was dominated by a sandy loam texture (62.50%) followed by a sandy clay loam texture (18.75%). The bulk density, total soil porosity and saturated hydraulic conductivity values varied with 1.38 - 1.55 Mg⋅cm<sup>−3</sup>, 41.85% - 48.45% and 1.20 - 3.34 cm⋅h<sup>−1</sup>, respectively. The chemical index ranged from low to moderate quality. The correlations between the parameters osculated between negative and positive. Therefore, the soil may be reclaimed if the soil properties are improved and crop selection is optimized for this soil. 展开更多
关键词 Land Reclamation Soil chemical and Physical Properties chemical Quality Index Fertility Quality Index
下载PDF
Ecological effect of the plantation of Sabina vulgaris in the Mu Us Sandy Land,China
3
作者 NAN Weige DONG Zhibao +2 位作者 ZHOU Zhengchao LI Qiang CHEN Guoxiang 《Journal of Arid Land》 SCIE CSCD 2024年第1期14-28,共15页
Vegetation restoration through artificial plantation is an effective method to combat desertification,especially in arid and semi-arid areas.This study aimed to explore the ecological effect of the plantation of Sabin... Vegetation restoration through artificial plantation is an effective method to combat desertification,especially in arid and semi-arid areas.This study aimed to explore the ecological effect of the plantation of Sabina vulgaris on soil physical and chemical properties on the southeastern fringe of the Mu Us Sandy Land,China.We collected soil samples from five depth layers(0-20,20-40,40-60,60-80,and 80-100 cm)in the S.vulgaris plantation plots across four plantation ages(4,7,10,and 16 years)in November 2019,and assessed soil physical(soil bulk density,soil porosity,and soil particle size)and chemical(soil organic carbon(SOC),total nitrogen(TN),available nitrogen(AN),available phosphorus(AP),available potassium(AK),cation-exchange capacity(CEC),salinity,p H,and C/N ratio)properties.The results indicated that the soil predominantly consisted of sand particles(94.27%-99.67%),with the remainder being silt and clay.As plantation age increased,silt and very fine sand contents progressively rose.After 16 years of planting,there was a marked reduction in the mean soil particle size.The initial soil fertility was low and declined from 4 to 10 years of planting before witnessing an improvement.Significant positive correlations were observed for the clay,silt,and very fine sand(mean diameter of 0.000-0.100 mm)with SOC,AK,and p H.In contrast,fine sand and medium sand(mean diameter of 0.100-0.500 mm)showed significant negative correlations with these indicators.Our findings ascertain that the plantation of S.vulgaris requires 10 years to effectively act as a windbreak and contribute to sand fixation,and needs 16 years to improve soil physical and chemical properties.Importantly,these improvements were found to be highly beneficial for vegetation restoration in arid and semi-arid areas.This research can offer valuable insights for the protection and restoration of the vegetation ecosystem in the sandy lands in China. 展开更多
关键词 Sabina vulgaris plantation age soil physical and chemical properties soil particle size soil fertility vegetation restoration Mu Us Sandy Land
下载PDF
Extended wet sieving method for determination of complete particle size distribution of general soils
4
作者 Shengnan Ma Yi Song +2 位作者 Jiawei Liu Xingyu Kang Zhongqi Quentin Yue 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第1期242-257,共16页
The traditional standard wet sieving method uses steel sieves with aperture?0.063 mm and can only determine the particle size distribution(PSD)of gravel and sand in general soil.This paper extends the traditional meth... The traditional standard wet sieving method uses steel sieves with aperture?0.063 mm and can only determine the particle size distribution(PSD)of gravel and sand in general soil.This paper extends the traditional method and presents an extended wet sieving method.The extended method uses both the steel sieves and the nylon filter cloth sieves.The apertures of the cloth sieves are smaller than 0.063 mm and equal 0.048 mm,0.038 mm,0.014 mm,0.012 mm,0.0063 mm,0.004 mm,0.003 mm,0.002 mm,and 0.001 mm,respectively.The extended method uses five steps to separate the general soil into many material sub-groups of gravel,sand,silt and clay with known particle size ranges.The complete PSD of the general soil is then calculated from the dry masses of the individual material sub-groups.The extended method is demonstrated with a general soil of completely decomposed granite(CDG)in Hong Kong,China.The silt and clay materials with different particle size ranges are further examined,checked and verified using stereomicroscopic observation,physical and chemical property tests.The results further confirm the correctness of the extended wet sieving method. 展开更多
关键词 Particle size distribution(PSD) General soil SILT CLAY Wet sieving Physical and chemical properties
下载PDF
State of the art review on physiochemical and engineering characteristics of fly ash and its applications
5
作者 Amit Kumar Ram Supriya Mohanty 《International Journal of Coal Science & Technology》 EI CAS CSCD 2022年第1期21-45,共25页
The focus of this study is to critically review the physiochemical and engineering properties of the fly ash and its applications in various fields.The utilization of fly ash has become a widespread area,but the amoun... The focus of this study is to critically review the physiochemical and engineering properties of the fly ash and its applications in various fields.The utilization of fly ash has become a widespread area,but the amount of utilization is still a serious issue.It has many beneficial qualities(such as pozzolanic property,fineness,spherical shape,lightweight,etc.),which enhance its properties and make it suitable for its utilization as a new construction material.For the bulk utilization of fly ash,it should be employed in the areas independent of any other parameters.So that,the disposal problem can be reduced significantly.The knowledge of its physiochemical characteristic helps in the judgment of appropriate fly ash for any particular type of work.Fly ash can be utilized in other areas such as asphalt concrete,geopolymer concrete,ground improvement,agricultural sector,roller compacted concrete,brick,etc.that will reduce the existing ashes,and also the disposal problem can be solved appreciably.The implementation of fly ash must be avoided below the natural ground water level and below 4°C temperature conditions. 展开更多
关键词 Fly ash chemical property Engineering property Construction material
下载PDF
Effect of fire severity on physical and biochemical soil properties in Zagros oak(Quercus brantii Lindl.)forests in Iran 被引量:13
6
作者 M.Heydari A.Rostamy +1 位作者 F.Najafi D.C.Dey 《Journal of Forestry Research》 SCIE CAS CSCD 2017年第1期95-104,共10页
Fire affects the physical and chemical properties and soil biological activity of natural ecosystems. This study was conducted in the Miyan Tang region, Ilam Province in western Iran. The study site was 110 hectares, ... Fire affects the physical and chemical properties and soil biological activity of natural ecosystems. This study was conducted in the Miyan Tang region, Ilam Province in western Iran. The study site was 110 hectares, where we sampled soils in areas that were classified by fire severity: low (LS), high (HS) and medium severity (MS), and unburned (UB), which served as the control. In each severity class, 25 transect points were randomly selected for measurement. Around each transect plot center, 3 soil samples were selected randomly and soils collected from the 0 to 20 cm depth were combined into a composite sample that was used in laboratory analysis to represent conditions at that point. Plots in the UB and LS fire classes had similar soil conditions and had higher values of factors such as saturated moisture, organic carbon, carbon dioxide, and silt and clay content. In contrast, plots in the HS and MS fire severity classes were clustered in the positive direction along the first axis that represented gradients in soil acidity, electrical conductivity, cation exchange capacity, accessible phosphorus, accessible potassium, bulk density, and sand. Soil attributes were similar in areas of HS and MS fire severity classes, whereas soil conditions in the LS class and UB controls were most similar. Fire in the LS areas either did not significantly alter the physicalchemical soil properties and microbial basal respiration, or soils were able to recover quickly after being burned. 展开更多
关键词 Fire severity OAK Soil respiration Physical and chemical soil properties
下载PDF
Spatial heterogeneity of soil chemical properties between Haloxylon persicum and Haloxylon ammodendron populations 被引量:11
7
作者 Li, CongJuan Li, Yan +2 位作者 Ma, Jian Fan, LianLian Wang, QinXue 《Journal of Arid Land》 SCIE 2010年第4期257-265,共9页
Spatial heterogeneity is a ubiquitous feature in natural ecosystems, especially in arid regions. Different species and their discontinuous distribution, accompanied by varied topographic characteristics, result in soi... Spatial heterogeneity is a ubiquitous feature in natural ecosystems, especially in arid regions. Different species and their discontinuous distribution, accompanied by varied topographic characteristics, result in soil resources distributed differently in different locations, and present significant spatial heterogeneity in desert ecosystems. In this study, conventional and geostatistical methods were used to identify the heterogeneity of soil chemical properties in two desert populations, Haloxylon persicum Bunge ex Boss., which dominates on the slopes and tops of sand dunes and Haloxylon ammodendron (C. A. Mey.) Bunge, which inhabits interdunes in the Gurbantunggut Desert of Xinjiang, China. The results showed that soil pH, electrical conductivity (EC), soil organic carbon (SOC), available nitrogen (AN) and available phosphorus (AP) were significantly higher in H. ammodendron populations than that in H. persicum. The coefficient of variation (CV) indicated that (1) most parameters presented a moderate degree of variability (10% 【 CV 【 100%) except pH in both plots, (2) the variability of soil pH, EC and AP in H. ammodendron populations was higher than that in H. persicum populations, and (3) SOC and AN in H. ammodendron populations were lower than that in H. persicum populations. Geostatistical analysis revealed a strong spatial dependence (C0/(C0+C) 【 25%) within the distance of ranges for all tested parameters in both plots. The Kriging-interpolated figures showed that the soil spatial distribution was correlated with the vegetation distribution, individual size of plants, and the topographic features, especially with the plants nearest to sampling points and the topographic features. In each plot, soil EC, SOC, AN and AP presented similar distributions, and fertile islands and salt islands occurred in both plots but did not affect every individual plant, since the sampling distance was larger than the size of such fertile islands. The results of topographic effects on soil heterogeneity suggested significant differences between the interdunes and dune-tops. Different topographic characteristics (physical factors) between plots result in the differences in SOC, AN and AP, while the heterogeneity of soil pH and EC arise from plant species and their distribution (biotic factor). Such biotic and physical factors did not occur in isolation, but worked together on soil heterogeneity, and played important parts in improving the soil properties. Hence these factors were ecologically valuable in the highly resource-stressed arid study area. 展开更多
关键词 fertile island GEOSTATISTICS plant population soil chemical properties spatial heterogeneity
下载PDF
Effects of reclaimed water irrigation and nitrogen fertilization on the chemical properties and microbial community of soil 被引量:8
8
作者 GUO Wei Mathias N Andersen +4 位作者 QI Xue-bin LI Ping LI Zhong-yang FAN Xiang-yang ZHOU Yuan 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2017年第3期679-690,共12页
The ecological effect of reclaimed water irrigation and fertilizer application on the soil environment is receiving more attention.Soil microbial activity and nitrogen(N)levels are important indicators of the effect... The ecological effect of reclaimed water irrigation and fertilizer application on the soil environment is receiving more attention.Soil microbial activity and nitrogen(N)levels are important indicators of the effect of reclaimed water irrigation on environment.This study evaluated soil physicochemical properties and microbial community structure in soils irrigated with reclaimed water and receiving varied amounts of N fertilizer.The results indicated that the reclaimed water irrigation increased soil electrical conductivity(EC)and soil water content(SWC).The N treatment has highly significant effect on the ACE,Chao,Shannon(H)and Coverage indices.Based on a 16S ribosomal RNA(16S rRNA)sequence analysis,the Proteobacteria,Gemmatimonadetes and Bacteroidetes were more abundant in soil irrigated with reclaimed water than in soil irrigated with clean water.Stronger clustering of microbial communities using either clean or reclaimed water for irrigation indicated that the type of irrigation water may have a greater influence on the structure of soil microbial community than N fertilizer treatment.Based on a canonical correspondence analysis(CCA)between the species of soil microbes and the chemical properties of the soil,which indicated that nitrate N(NO3-–-N)and total phosphorus(TP)had significant impact on abundance of Verrucomicrobia and Gemmatimonadetes,meanwhile the p H and organic matter(OM)had impact on abundance of Firmicutes and Actinobacteria significantly.It was beneficial to the improvement of soil bacterial activity and fertility under 120 mg kg^-1 N with reclaimed water irrigation. 展开更多
关键词 reclaimed water NITROGEN soil chemical properties 16S rRNA sequence soil microbe community
下载PDF
Preparation and Electrochemical Properties of 3-Pyridinyl-6-aryl-1,2,4-triazolo [3,4-b][1, 3,4]thiadiazoles 被引量:3
9
作者 TaiXIAO HuiXueLI +1 位作者 ChunXiaTAN MiaoCHEN 《Chinese Chemical Letters》 SCIE CAS CSCD 2005年第3期335-337,共3页
关键词 PREPARATION 3-pyridinyl-6-aryl-1 2 4-triazolo[3 4-b][1. 3 4]thiadiazoles electro- chemical properties.
下载PDF
Effect of land-use changes on chemical and physical properties of soil in western Iran(Zagros oak forests) 被引量:3
10
作者 Kyumars Mohmmadi Samani Narges Pordel +1 位作者 Vahid Hosseini Zahed Shakeri 《Journal of Forestry Research》 SCIE CAS CSCD 2020年第2期637-647,共11页
The consequence of land-use change from forest to agriculture and other uses has become one of the world’s greatest concerns.The soil,one of the most important components of forests and containing all the required pl... The consequence of land-use change from forest to agriculture and other uses has become one of the world’s greatest concerns.The soil,one of the most important components of forests and containing all the required plant nutrients as soluble ions,is highly impacted by these changes.Because vast areas of the Zagros forests in western Iran have changed in use during the last few decades,the present study investigated the effects of landuse changes of forest area to agriculture,orchard,and agroforestry on soil chemical and physical properties.Soil was sampled at four land-use areas:less-disturbed forest areas(control)and agricultural,orchard,and agroforestry areas.Among each of the two forest-use areas(agroforestry and orchard),we selected five trees with similar-sized crowns and sampled under each tree crown at 0-15 and>15-30 cm depths.Five soil samples also were taken in agriculture area at each depth.The findings indicated that during land-use changes,soil sand particles decreased,and clay and silt particles of soil increased,resulting in a fine soil texture.Moreover,the amount of nitrogen(N),phosphorus(P),organic carbon(OC),and electrical conductivity(EC)of soil decreased at both depths due to the decrease in organic matter.Soil pH and magnesium(Mg)level rose during land-use change at both depths except at agricultural sites.Soil potassium(K)content decreased during agricultural use due to the elimination of tree cover.The level of K decreased only at the depth of 0-15 cm because of K dependency on parent materials.Generally,most soil nutrients were affected by plant removal in the conversion.Forest and agricultural soil are distinguishable by their properties,while land-uses such as agroforestry-orchard separated from the others.Soil nutrients were severely affected by the decrease and elimination of tree cover,plowing,and continuous harvesting,resulting in a decline in soil quality and fertility. 展开更多
关键词 chemical soil properties Land-use change AGROFORESTRY AGRICULTURE Zagros Oak forest
下载PDF
The Effects of the Chemical Components of Soil Salinity on Electrical Conductivity in the Region of the Delta Oasis of Weigan and Kuqa Rivers,China 被引量:4
11
作者 ZHANG Fei Tashpolat Tiyip +2 位作者 DING Jian-li Gregory N Taff HE Qi-sheng 《Agricultural Sciences in China》 CSCD 2009年第8期985-993,共9页
In order to assess the effects of chemical properties of soil salinity on electrical conductivity of 1:5 soil/water extract (EC1:5), the study focused on revealing the main chemical factors contributing to EC of s... In order to assess the effects of chemical properties of soil salinity on electrical conductivity of 1:5 soil/water extract (EC1:5), the study focused on revealing the main chemical factors contributing to EC of soil extracts and their relative importance. The relationship between EC1:5 and the chemical properties of soil salinity in the delta oasis of Weigan and Kuqa rivers, China, were studied using path coefficient analysis, a path analysis method. We studied each key element affecting EC1:5 either directly or indirectly. The results obtained show that the salt content, total dissolved solids (TDS), and the sum of the sodium ion concentration and the kalium ion concentration are the most influential factors on 1:5 soil/ water extract (EC1:5) in the 0-10 cm and the 30-50 cm soil layer. The results show that the sequence of direct path coefficients in the 0-10 cm and the 30-50 cm soil layers on soil conductivity is TDS→Na^+ + K^+→Salt content→Ca^2+→Cl-→the sodium dianion ratio (SDR)→pH→ SO4^2-→HCO3^-→Mg^2+→the soluble sodium percentage (SSP) sodium absorption ratio (SAR) and TDS→Salt content→Na^+ + K^+→Ca^2+→SDR→Mg^2+→HCO3^-→SSP→pH→SO4^2-→SAR→Cl^-. The salt content, chlorine ion, and SAR are the main factors affecting 1:5 soil/water extract (EC1:5) in the 10-30 centimeter soil layer. The order of direct path coefficients result is as follows: Salt content→Cl^-→SAR→SSP→TDS→Ca^2+→Mg^2+= SO4^2-→HCO3^-→pH→SDR→Na^- + K^+. Moreover, the effects of HCO3^-, pH were very weak. Though the direct path coefficients between EC1:5 and SAR, SO4^2- and Ca^2+ were not high, influence of other chemical factors caused the coefficients to increase, making the summation of their direct and indirect path coefficients relatively high. The models of the different soil layers were structured separately. Evidences showed that multiple regression relations between EC1:5 and most of the primary factors had sound reliability and very good accuracy. The research results can serve as a reference to the scientific management amelioration and utilization of saline in the Delta Oasis of Weigan and Kuqa rivers. 展开更多
关键词 chemical properties of soil electrical conductivity of soil soil salinity the delta oasis of Weigan and Kuqa rivers
下载PDF
Effects of bioleaching on the mechanical and chemical properties of waste rocks 被引量:2
12
作者 Sheng-hua Yin Ai-xiang Wu +1 位作者 Shao-yong Wang Chun-ming Ai 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2012年第1期1-8,共8页
Bioleaching processes cause dramatic changes in the mechanical and chemical properties of waste rocks, and play an important role in metal recovery and dump stability. This study focused on the characteristics of wast... Bioleaching processes cause dramatic changes in the mechanical and chemical properties of waste rocks, and play an important role in metal recovery and dump stability. This study focused on the characteristics of waste rocks subjected to bioleaching. A series of ex- periments were conducted to investigate the evolution of rock properties during the bioleaching process. Mechanical behaviors of the leached waste rocks, such as failure patterns, normal stress, shear strength, and cohesion were determined through mechanical tests. The results of SEM imaging show considerable differences in the surface morphology of leached rocks located at different parts of the dump. The minera- logical content of the leached rocks reflects the extent of dissolution and precipitation during bioleaching. The dump porosity and rock size change under the effect of dissolution, precipitation, and clay transportation. The particle size of the leached rocks decreased due to the loss of rock integrity and the conversion of dry precipitation into fine particles. 展开更多
关键词 BIOLEACHING mechanical properties chemical properties waste rocks
下载PDF
Dynamic Changes of Chemical and Mechanical Properties of Moso Bamboo (Phyllostachys edulis) Culms under Different Storage Conditions 被引量:1
13
作者 Hui Zhan Zhaohui Niu +3 位作者 Lixia Yu Maobiao Li Changming Wang Shuguang Wang 《Journal of Renewable Materials》 SCIE EI 2021年第5期1031-1043,共13页
The durability of bamboo based on its chemical and mechanical properties is a crucial consideration for the wood-based industry due to its vulnerability to insects and microorganisms.We investigated the dynamic change... The durability of bamboo based on its chemical and mechanical properties is a crucial consideration for the wood-based industry due to its vulnerability to insects and microorganisms.We investigated the dynamic changes of chemical and mechanical properties of Phyllostachys edulis under air-dry and water storage conditions for 3,6 and 12 months respectively.The chemical properties of P.edulis bamboo culms varied with culm age but insignificantly with culm height.The mechanical properties of P.edulis culms showed an increasing trend with culm age.Water storage condition decreased the ash,SiO2 and lignin content,but increased the ethanol-benzene extracts.It also created an anaerobic environment for bamboo culms in which only anaerobic respiration was possible contributing to reducing the content of soluble sugar and starch,thereby beneficial for decreasing the damage from insects and microorganisms.Moreover,the water storage conditions could maintain culm mechanical performance better.Therefore,the indigenous practice of local people to store bamboo culms in ponds has good science behind it and water storage practices of bamboo culms was recommended. 展开更多
关键词 Phyllostachys edulis chemical properties mechanical properties storage conditions
下载PDF
Robinia pseudoacacia leaves improve soil physical and chemical properties 被引量:1
14
作者 Babar KHAN Abdukadir Ablimit +1 位作者 Rashed MAHMOOD Muhammad QASIM 《Journal of Arid Land》 SCIE 2010年第4期266-271,共6页
The role of the leaves of Robinia pseudoacacia L., which is widely distributed in the arid lands, on improving soil physical and chemical properties was analyzed at various incubation periods. The incubated soils adde... The role of the leaves of Robinia pseudoacacia L., which is widely distributed in the arid lands, on improving soil physical and chemical properties was analyzed at various incubation periods. The incubated soils added with 0, 25, 50 and 75 g Robinia pseudoacacia leaves were tested after consecutive incubation intervals of 6, 8 and 10 months and the different soil parameters were measured. The results showed the increases in organic matter (OM), extractable K, cation exchange capacity (CEC), aggregate stability and water holding capacity, but the decreases in pH value and bulk density after 6 months’ incubation. The gradual decrease in change rates of soil properties indicated less microbial population and organic residual mineralization under acidic conditions, which were resulted from fast decomposition of leaves after the first 6 months incubation. The increases in soil organic matter content, extractable K, CEC, aggregate stability and water holding capacity and the decreases in soil pH and bulk density provide favorable conditions for crop’s growth. 展开更多
关键词 soil physical and chemical properties Robinia pseudoacacia Gilgit-Baltistan
下载PDF
Effect of chemical and organic fertilization on soil carbon and nitrogen accumulation in a newly cultivated farmland 被引量:7
15
作者 YANG Rong SU Yong-zhong +1 位作者 WANG Tao YANG Qin 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2016年第3期658-666,共9页
Increased food demand from the rapidly growing human population has caused intensive land transition from desert to farmland in arid regions of northwest China. In this developing ecosystem, the optimized fertilizatio... Increased food demand from the rapidly growing human population has caused intensive land transition from desert to farmland in arid regions of northwest China. In this developing ecosystem, the optimized fertilization strategies are becoming an urgent need for sustainable crop productivity, efficient resources use, together with the delivery of ecosystems services including soil carbon(C) and nitrogen(N) accumulation. Through a 7-year field experiment with 9 fertilization treatments in a newly cultivated farmland, we tested whether different fertilizations had significant influences on soil C and N accumulation in this developing ecosystem, and also investigated possible mechanisms for this influence. The results showed that applying organic manure in cultivated farmland significantly increased the soil C and N accumulation rates; this influence was greater when it was combined with chemical fertilizer, accumulating 2.01 t C and 0.11 t N ha^(–1) yr^(–1) in the most successful fertilization treatment. These high rates of C and N accumulation were found associated with increased input of C and N, although the relationship between the N accumulation rate and N input was not significant. The improved soil physical properties was observed under only organic manure and integrated fertilization treatments, and the significant relationship between soil C or N and soil physical properties were also found in this study. The results suggest that in newly cultivated farmland, long term organic manure and integrated fertilization can yield significant benefits for soil C and N accumulation, and deliver additional influence on physical properties. 展开更多
关键词 C and N accumulation sandy farmland chemical fertilizer manure soil physical property
下载PDF
Chemical, mechanical, and thermal expansion properties of a carbon nanotube-reinforced aluminum nanocomposite 被引量:2
16
作者 Manjula Sharma Vimal Sharma 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2016年第2期222-233,共12页
In the present study,the chemical and mechanical properties and the thermal expansion of a carbon nanotube(CNT)-based crystalline nano-aluminum(nano Al) composite were reported.The properties of nanocomposites wer... In the present study,the chemical and mechanical properties and the thermal expansion of a carbon nanotube(CNT)-based crystalline nano-aluminum(nano Al) composite were reported.The properties of nanocomposites were tailored by incorporating CNTs into the nano Al matrix using a physical mixing method.The elastic moduli and the coefficient of thermal expansion(CTE) of the nanocomposites were also estimated to understand the effects of CNT reinforcement in the Al matrix.Microstructural characterization of the nanocomposite reveals that the CNTs are dispersed and embedded in the Al matrix.The experimental results indicate that the incorporation of CNTs into the nano Al matrix results in the increase in hardness and elastic modulus along with a concomitant decrease in the coefficient of thermal expansion The hardness and elastic modulus of the nanocomposite increase by 21%and 20%,respectively,upon CNT addition.The CTE of CNT/A1 nanocomposite decreases to 70%compared with that of nano Al. 展开更多
关键词 metal matrix composites carbon nanotubes nanocomposites chemical properties thermal expansion mechanical properties
下载PDF
Application of Biochemical Fulvic Acid Potassium in Transplantation of Trees 被引量:1
17
作者 Yang Qunhui He Xiang +6 位作者 Bi Yunqing Yang Peiwen Zhang Qing Yang Mingying Shi Zhufeng Peng Rongzhen Wang Jiayin 《Plant Diseases and Pests》 CAS 2020年第2期16-19,共4页
[Objective]The paper was to clarify the application of biochemical fulvic acid potassium on the survival rate and growth of various trees transplanted in the process of landscaping.[Method]Two experimental treatments(... [Objective]The paper was to clarify the application of biochemical fulvic acid potassium on the survival rate and growth of various trees transplanted in the process of landscaping.[Method]Two experimental treatments(i.e.decomposed organic fertilizer+biochemical fulvic acid potassium water soluble fertilizer,decomposed organic fertilizer+compound fertilizer)were designed to determine the changes in physical and chemical properties before and after soil treatment,and the survival rate,plant height and ground diameter of four different cultivated plants within one year,and the effects of applying biochemical fulvic acid potassium on cultivated plants were investigated.[Result]The soil organic matter,total nitrogen,alkali-hydrolyzable nitrogen,soil available phosphorus,soil available potassium and p H value in the soil treated with decomposed organic fertilizer+biochemical fulvic acid potassium soluble fertilizer,and decomposed organic fertilizer+compound fertilizer increased significantly,and the soil bulk density decreased obviously.The survival rates,plant heights and ground diameters of four different cultivated plants were significantly improved after application of decomposed organic fertilizer+biochemical fulvic acid potassium water soluble fertilizer,and decomposed organic fer-tilizer+compound fertilizer(P<0.05).[Conclusion]The application of biochemical fulvic acid potassium on cultivated plants effectively improved soil fertility,increased the utilization of nitrogen,phosphorus and potassium,improved the growth of plants,and promoted the growth of landscaping plants after transplantation. 展开更多
关键词 Biochemical fulvic acid potassium TRANSPLANTATION Physical and chemical properties APPLICATION
下载PDF
Cameroon Green Energy Potentials: Field Survey of Production, Physico-Chemical Analyses of Palm Kernel Oil for Industrial Applications 被引量:1
18
作者 Alang Michael Bong Ndikontar Maurice Kor Peter T. Ndifon 《Green and Sustainable Chemistry》 2020年第3期57-71,共15页
This paper reports a field survey undertaken to determine the availability of raw material for palm kernel oil commercial production for industrial applications. Both industrial and artisanal wastes from palm kernel o... This paper reports a field survey undertaken to determine the availability of raw material for palm kernel oil commercial production for industrial applications. Both industrial and artisanal wastes from palm kernel oil production were also surveyed as raw material (palm kernel seeds) for green energy production. Results of the field study show that 22% of palm kernel seeds (which represents tons of waste) resulting from palm oil processing plants are dumped while at the artisanal level, 80% of palm kernel seed waste is dumped. Analysis of field study data show<span>s</span><span> that large amounts of waste palm kernel seeds are available to enable large scale production of palm kernel oil (PKO) for desirable industrial applications in green energy production. The paper also reports on the physical and chemical properties of Cameroon palm kernel oil (PKO). Palm kernel oil was extracted using mechanical press and solvent extraction. The palm kernel oil (PKO) from Cameroon was analyzed by standard physico-chemical methods. Results of the physical measurements show a specific gravity of PKO of 0.92 kg/L, viscosity of 26.03 cSt and at 5.93 cSt at 40<span style="color:#4F4F4F;font-family:" font-size:14px;white-space:normal;background-color:#ffffff;"=""><span style="color:#4F4F4F;font-family:"font-size:14px;white-space:normal;background-color:#FFFFFF;">&#176;</span></span>C and 100<span style="color:#4F4F4F;font-family:" font-size:14px;white-space:normal;background-color:#ffffff;"=""><span style="color:#4F4F4F;font-family:"font-size:14px;white-space:normal;background-color:#FFFFFF;">&#176;</span></span>C respectively, viscosity index of 185, pour point of 20<span style="color:#4F4F4F;font-family:" font-size:14px;white-space:normal;background-color:#ffffff;"=""><span style="color:#4F4F4F;font-family:"font-size:14px;white-space:normal;background-color:#FFFFFF;">&#176;</span></span>C, cloud point of 29<span style="color:#4F4F4F;font-family:" font-size:14px;white-space:normal;background-color:#ffffff;"=""><span style="color:#4F4F4F;font-family:"font-size:14px;white-space:normal;background-color:#FFFFFF;">&#176;</span></span>C, flash point of 200<span style="color:#4F4F4F;font-family:" font-size:14px;white-space:normal;background-color:#ffffff;"=""><span style="color:#4F4F4F;font-family:"font-size:14px;white-space:normal;background-color:#FFFFFF;">&#176;</span></span>C, aniline point of 105<span style="color:#4F4F4F;font-family:" font-size:14px;white-space:normal;background-color:#ffffff;"=""><span style="color:#4F4F4F;font-family:"font-size:14px;white-space:normal;background-color:#FFFFFF;">&#176;</span></span>F, diesel index of 23, cetane number of 27 and ASTM (American Standards for Testing and Materials) color of less than 2.5. Results of chemical analyses showed an acid val<span>ue of 17.95 mg KOH/g, free fatty <span>acid (FFA) content of 8.98 mg KOH/g, iodine value o</span></span></span><span><span><span>f 2.10</span><span> mg</span></span></span><span> </span><span><span style="font-family:Verdana;">I</span><sub><span style="font-family:Verdana;">2</span></sub><span><span style="font-family:Verdana;">/g</span><span style="font-family:Verdana;">, peroxide value of 2.10 meq/kg, ester value of 123.0 mg KOH/g, hydroxyl value of 93.4 mg OH/g, saponification value of 140.95 mg KOH/g and a sulfur content of 0.016% w/v, signifying low sulfur content. Gas chromatography-mass spectrometry (GC-MS) showed the palm kernel oil to be predominantly made up of glycerides of various fatty acids with higher proportions of C12 to C16 fatty acid residues. Cameroon PKO therefore has a broad spectrum of industrial applications by virtue of its rich physical and chemical properties.</span></span></span> 展开更多
关键词 Field Survey Palm Kernel Oil Raw Material Energy Production Physical and chemical Properties Fatty Acids Iodine Value GC-MS
下载PDF
Hydrothermal Synthesis,Crystal Structure,Spectrum Properties and Quantum Chemical Calculation of a Trinuclear Copper(Ⅱ) Complex with 3-(Pyridin-2-yl)-1,2,4-triazole 被引量:1
19
作者 李昶红 李薇 +1 位作者 李玉林 杨颖群 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 2012年第8期1089-1094,共6页
A three-dimensional framework copper(Ⅱ) coordination polymer with copper carbonate basic and 3-(pyridin-2-yl)-1,2,4-triazole (Hpt) has been hydrothemally synthesized.The complex (2,C14 H10 CuN8 ·3H2 O) c... A three-dimensional framework copper(Ⅱ) coordination polymer with copper carbonate basic and 3-(pyridin-2-yl)-1,2,4-triazole (Hpt) has been hydrothemally synthesized.The complex (2,C14 H10 CuN8 ·3H2 O) crystallizes in tetragonal,space group P4 2 /n,a=2.08581(12),b=2.08581(12),c=0.72331(4) nm,M r=761.73,V=3.1468(3) nm 3,Dc=1.608 g/cm 3,Z=4,F(000)=1552,GOOF=1.07,R=0.0515 and wR=0.1689.Every asymmetric unit molecular structure of the complex is composed with one copper ion,one and half water molecules and two Hpt molecules.Each copper ion is coordinated with five nitrogen atoms from four Hpt molecules,forming a distorted square pyramidal geometry.The fluorescence spectrum analysis shows that the title complex at room temperature exhibits intense photoluminescence with maximum emission at 450 nm.The quantum chemistry calculation study on the complex has been performed.The stability,some frontier molecular orbital energies and composition characteristics of some frontier molecular orbitals of the complex have been investigated. 展开更多
关键词 trinuclear copper complex hydrothermal synthesis spectrum properties quantum chemical calculation
下载PDF
Chemical expansion of solid oxide fuel cell materials: A brief overview 被引量:2
20
作者 S.R.Bishop 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2013年第3期312-317,共6页
The importance of oxygen non-stoichiometry induced expansion, known as chemical expansion, for the mechanical properties of solid oxide fuel cells (SOFCs) is discussed. The methods used to measure chemical expansion... The importance of oxygen non-stoichiometry induced expansion, known as chemical expansion, for the mechanical properties of solid oxide fuel cells (SOFCs) is discussed. The methods used to measure chemical expansion and the defects responsible for its existence are introduced. Recent work demonstrating the origin of chemical expansion in fluorite structured oxides for SOFCs is presented. Models used to predict stress induced by chemical expansion in SOFCs, highlighting the necessity of considering electro-chemo-mechanical coupling relationships, are discussed. 展开更多
关键词 Defect equilibria · SOFC mechanical properties · chemical expansion
下载PDF
上一页 1 2 5 下一页 到第
使用帮助 返回顶部