Missing data are a problem in geophysical surveys, and interpolation and reconstruction of missing data is part of the data processing and interpretation. Based on the sparseness of the geophysical data or the transfo...Missing data are a problem in geophysical surveys, and interpolation and reconstruction of missing data is part of the data processing and interpretation. Based on the sparseness of the geophysical data or the transform domain, we can improve the accuracy and stability of the reconstruction by transforming it to a sparse optimization problem. In this paper, we propose a mathematical model for the sparse reconstruction of data based on the LO-norm minimization. Furthermore, we discuss two types of the approximation algorithm for the LO- norm minimization according to the size and characteristics of the geophysical data: namely, the iteratively reweighted least-squares algorithm and the fast iterative hard thresholding algorithm. Theoretical and numerical analysis showed that applying the iteratively reweighted least-squares algorithm to the reconstruction of potential field data exploits its fast convergence rate, short calculation time, and high precision, whereas the fast iterative hard thresholding algorithm is more suitable for processing seismic data, moreover, its computational efficiency is better than that of the traditional iterative hard thresholding algorithm.展开更多
Lubricating mineral base oils are normally extracted from lube-oil cuts with furfural solvent.Aromatic content in the raffinate phase from extraction process is an essential parameter that affects the quality of the l...Lubricating mineral base oils are normally extracted from lube-oil cuts with furfural solvent.Aromatic content in the raffinate phase from extraction process is an essential parameter that affects the quality of the lubricating base-oils.For determination of aromatic content by the usual ASTM D3238 method,density,refractive index and molecular weight of the raffinate are required.In this work,a new generalized correlation is developed for de-termination the aromatic content by using only the measured viscosity of lubricating oil.With a mole fraction of aromatic compounds,the kinematic viscosity may be obtained at any temperature between 60-100°C along with their molecular weight and refractive index.展开更多
Physical-chemical properties of phosphorous gypsum, proportion and cemented mechanism of slurry with gypsum as aggregate were studied to remove the harms of gypsum pile, combining with difficult problems of excessive ...Physical-chemical properties of phosphorous gypsum, proportion and cemented mechanism of slurry with gypsum as aggregate were studied to remove the harms of gypsum pile, combining with difficult problems of excessive mined-out gobs, enormous ore body under roadway and low recovery ratio of Yongshaba Mine, Kaiyang Phosphor Mine Group, Guizhou Province, China. An appropriate backfill system and craflwork were designed, using shattering milling method to crush gypsum, double-axles mixing and strong activation mixing way to mix slurry, cemented slurry and mullock backfill alternately process. The results show that gypsum is fit for backfilling afterwards by adding fly ash, though it is not an ideal aggregate for fine granule and coagulate retardation. The suggested dosage (the mass ratio of cement to fly ash to gypsum) is 1:1:6-1:1:8 with mass fraction of solid materials 60%-63%. Slurry is transported in suspend state with non-plastic strength, and then in concretion state after backfilling. The application to mine shows the technology is feasible, and gypsum utilization ratio is up to 100%. Transportation and backfill effect is very good for paste-like slurry and drenching cemented slurry into mullock, and the compressive strength and recovery ratio are 2.0 MPa and 82.6%, respectively, with the maximum subsidence of surface only 1.307 mm. Furthermore, the investment of system is about 7 × 10^6 yuan (RMB), only 1/10 of that of traditional paste backfill system.展开更多
To facilitate the development of the basis for the selection of plants for re-vegetating tailings in Zambia, an as sessment of the performance of tree species growing on tailings dams was conducted. The performance of...To facilitate the development of the basis for the selection of plants for re-vegetating tailings in Zambia, an as sessment of the performance of tree species growing on tailings dams was conducted. The performance of species was determined in terms of relative density, frequency and importance value for each species. The study reveals variations in performance of species; for example in terms of importance values, Acacia polyacantha (33.5%), Toona ciliata (21.4%), Acacia sieberana (9.9%), Bauhinia thonningii (9.1%) and Peltophorum africanum (8.3%) were the most dominant species. The dominance of these species on tailings dams demonstrates tolerance to railings dams conditions. The study recommends that emphasis must be placed on these species in re-vegetating tailings dams.展开更多
It is of great significance for cleaner production to substitute bio-energy for fossil fuels in iron ore sintering. However, with the replacement ratio increasing, the consistency of heat front and flame front is brok...It is of great significance for cleaner production to substitute bio-energy for fossil fuels in iron ore sintering. However, with the replacement ratio increasing, the consistency of heat front and flame front is broken, and the thermal utilizing efficiency of fuel is reduced, which results in the decrease of yield and tumble index of sinter. Circulating flue gas to sintering bed as biochar replacing 40% coke, CO in flue gas can be reused so as to increase the thermal utilizing efficiency of fuels, and the consistency of two fronts is recovered for the circulating flue gas containing certain CO2, H2 O and lower O2, which contributes to increasing the maximum temperature, extending the high temperature duration time of sintering bed, and results in improving the output and quality of sinter. In the condition of circulating 40% flue gas, the sintering with biomass fuels is strengthened, and the sintering indexes with biomass fuel replacing 40% coke breeze are comparative to those of using coke breeze completely.展开更多
In order to provide a new way for waste cooking oil(WCO) resource utilization, several diester derivatives were obtained from WCO through a three-step chemical modifications, viz.: transesterification, epoxidation and...In order to provide a new way for waste cooking oil(WCO) resource utilization, several diester derivatives were obtained from WCO through a three-step chemical modifications, viz.: transesterification, epoxidation and oxirane ring opening with carboxylic acids. The effects of the chain length of side chain groups on the viscosity, acid value, low temperature fluidity, thermo-oxidative stability, tribological properties and surface tension of diester derivatives were investigated. The results showed that increasing the chain length of side chain groups had a positive influence on the viscosity, viscosity index, acid value, pour point, friction coefficient and wear scar diameter along with a negative influence on the oxidation onset temperature, volatile loss, insoluble deposit, maximum non-seizure load and surface tension. These diester derivatives exhibited improved physicochemical and tribological properties that make themselves promising environmentally friendly biolubricant basestocks.展开更多
A paste-like self-flowing pipeline transportation backfilling technology with coal gangue as aggregate is proposed to remove the potential damage caused by coal gangue piles. As well, the difficult problems of recover...A paste-like self-flowing pipeline transportation backfilling technology with coal gangue as aggregate is proposed to remove the potential damage caused by coal gangue piles. As well, the difficult problems of recovering high quality safety coal pillars and deep mining of the Suncun Coal Mine (SCM), Xinwen Coal Group, Shandong are resolved. The physical-chemical properties of coal gangue, optimized proportion of materials, backfilling system and craft in the SCM were studied in the laboratory and then an industrial test was carried out on high quality coal pillars under a town. The results show that finely crushed kaolinized and fresh gangue with granularity less than 5 mm can be used as aggregate with fly ash to replace part of the cement and a composite water reducer as an additive, accounting for 1.0%-1.5% of the total amount of cement and fly ash. The recommended proportion is l(cement):4(fly ash): 15(coal gangue), with a mass fraction of 72%-75%, rheoiogical paste-like properties and a strength of more than 0.7 MPa at 7 d. The sequence of adding cement, fly ash, water reducer and then coal gangue ensures that the suspended state of the slurry, reducing the wear and jam of pipelines. The working face is advancing continuously by the alternating craft of building block walls with coal gangue and backfilling mined-out gobs with paste-like slurry. The recovery rate is as high as 90% with a backfilling cost of 36.9 YuarffL good utilization of coal gangue and no subsidence on the surface. This technology provides a good theoretical basis and application experience for coal mines, cement backfilling with paste-like slurry.展开更多
An experiment was conducted to evaluate the growth performance and cost per gain of Brahman × local crossbred bull calves receiving three diets with varying concentrate to roughage ratio (C:R) of 75:25, 65:3...An experiment was conducted to evaluate the growth performance and cost per gain of Brahman × local crossbred bull calves receiving three diets with varying concentrate to roughage ratio (C:R) of 75:25, 65:35 and 55:45 on dry matter (DM) basis. Twelve bull calves (aging 11.5 ±1.2 months and 170.8 ± 13.0 kg live weight) divided into three equal groups were fed on three diets. The diets were balanced to 14.5% crude protein (CP) level and 10.5 MJ metabolizable energy (ME) per kg DM, formulating different concentrate mixtures. German grass (Echinoclora grousgali) and paddy straw were offered at 2:1 ratio on DM basis as roughages. The results revealed that C:R ratio did not affect (P 〉 0.05) the intake of feed and nutrients, feed efficiency (7.04, 6.94 and 6.76) and average daily gain (981,958 and 976 g). Digestibility of nutrients was not affected (P 〉 0.05) by C:R. Animals fed diet with C:R = 55:45 had the lowest feed cost (Bangladeshi Taka 136.8 BDT/kg live weight gain), which was increased (147.5 B DT and 153.8 BDT) non-significantly (P 〉 0.05) with the increasing level of concentrate. The diet consisting of 55% concentrate mixture showed similar results with the diet consisting of 75% concentrate mixture, but was comparatively economic. Therefore, considering the growth performance and cost per kg gain of Brahman crossbred growing calves, it may be concluded that the diet consisting of 55:45 C:R may be used for economic beef production.展开更多
In the past decade,the advent of the epidermal growth factor receptor-tyrosine kinase inhibitors(EGFR-TKIs)has dramatically influenced the therapeutic strategies for treating lung cancer,but with tumor progression and...In the past decade,the advent of the epidermal growth factor receptor-tyrosine kinase inhibitors(EGFR-TKIs)has dramatically influenced the therapeutic strategies for treating lung cancer,but with tumor progression and drug resistance,patients will ultimately develop reduced sensitivity to EGFR-TKIs.How can we delay the emergence of drug resistance? What is the next strategy after drug resistance? How to reasonably combine platinum-based chemotherapy and EGFR-TKIs? These questions are currently the focus of lung cancer research.Clinical studies have reported that platinum-based chemotherapy can increase the sensitivity to EGFR-TKIs.However,results of pre-clinical and clinical studies have been inconsistent.The mechanisms of platinum chemotherapy and EGFR-TKIs are still unknown due to the lack of systematic research.Therefore,systematic studies are required to show the mechanisms of EGFR-TKIs and chemotherapy agents and define the markers sensitive to their combinations when given concurrently or sequentially.展开更多
Geosciences and statistics were applied to develop predictive models to study the areas of risk to soybean rust (Phakopsora pachyrhizi Sydow) in soybean (Glycine max L.), coffee leaf rust (Hemileia vastatrix Berk...Geosciences and statistics were applied to develop predictive models to study the areas of risk to soybean rust (Phakopsora pachyrhizi Sydow) in soybean (Glycine max L.), coffee leaf rust (Hemileia vastatrix Berk & Br) in coffee and Black Sigatoka (Mycosphaerella fijiensis var. difformis) in banana, considering to Brazilian climatic characterization and distribution of soybean, coffee and banana crops in the period of observed data of 1950 to 2000 and A2 climate change scenarios of simulated data of 2020, 2050 and 2080. The technique of principal components allowed generating 1 variable based on 57 variables in order to determine an index explaining 87%, 88% and 90% of the variability of soybean, coffee and banana crops in Brazilian municipal districts. The climatic model of each disease was used to generate the zoning of the coffee rust, soybean rust and black sigatoka based on temperature and leaf wetness. Areas of favorability of the diseases were plotted inside to the main coffee, soybean and banana growing in Brazil. The applied methodology enabled to visualize the variation of favorable areas of epidemics according to the studied scenarios of climate change.展开更多
Seismic gap method is one of the effective earthquake prediction methods using seismicity patterns. However, this method has some limitations and uncertainty when using it singly in predicting earthquakes. This paper ...Seismic gap method is one of the effective earthquake prediction methods using seismicity patterns. However, this method has some limitations and uncertainty when using it singly in predicting earthquakes. This paper puts forward the prediction method using the dynamic seismicity pattern with dynamic implications. This method considers the formation and evolution of the seismic gap on the basis of plate movement and structural characteristics. Through analysis of 26 cases of earthquakes of MS≥5.0 occurring in East China and South China, this paper obtains the relationship between the main shock with seismic gap and active fault's location, as well as the relationship between the seismic gap and location and strike of active faults. Meanwhile, this paper provides a dynamic explanation of the differences in the formation and evolution patterns of the seismic gap between the two regions, thus providing the physical basis for and reducing the uncertainty of predicting earthquakes using the seismic gap method.展开更多
The production of chemicals from biomass is a very challenging process due to its diverse chemical composition. Lignin, cellulose and hemicellulose are the three main biopolymers of wood biomass, with cell walls &pla...The production of chemicals from biomass is a very challenging process due to its diverse chemical composition. Lignin, cellulose and hemicellulose are the three main biopolymers of wood biomass, with cell walls &plant origin. Lignin has been chosen for the present studies due to its range of different linkages and structures. The present work involved a computational study of the most dominant lignin dimers and their vibrational structures, based on the Density Functional Theory method. Full geometry optimization of the compartments used the StoBe code with cluster model and non-local functional (RPBE) approach. The calculations of the vibrational frequencies were performed with harmonic approximations as well as an anharmonicity fit in the Morse potential function, as implemented in the StoBe code. In the case oflignin, the calculations included three different precursors based on: coumaryl alcohol, coniferyl alcohol and sinapyl alcohol. To represent the cellulose and hemicellulose derivatives, selected aldopentoses and aldohexoses (arabinose, xylose, glucose, galactose, and mannose) were considered. Presented here are the theoretical investigations for a variety of biomass derived compounds, to give the possibility of obtaining a theoretical VBD (Vibrations Basis Database) for experimental spectra interpretation. Such a database could be further used in the preliminary composition assessment of biomass derived substrates, which will be discussed here in more detail.展开更多
In Japan, each municipality generally has its own municipal solid waste incineration facilities because of the principle of self-management in the respective territories. Typically, a small municipality often owns a s...In Japan, each municipality generally has its own municipal solid waste incineration facilities because of the principle of self-management in the respective territories. Typically, a small municipality often owns a small facility. However, a large facility which can run continuously at high temperature with stability would be preferable if the dioxin generation mechanism is to be considered. Accordingly, municipalities in contiguous areas should cooperate mutually by using a large facility. To evaluate the effect of the concentration of large facilities, the authors created a GIS (Geographic Information System) based database of combustible waste generation at town level in Shizuoka Prefecture. Focusing on large facilities in Shizuoka City and superannuated facilities in Shida area, the authors evaluated the effect of the concentration of large facilities in Shizuoka city on utilization rate of facilities, energy balance and CO2 emissions. Our results showed the amount of light oil consumption and CO2 emissions increased because the mileage distance of garbage collection trucks becomes longer. However, the utilization rates of facilities and the amount of energy recovery from waste are improved. From these standpoints, the authors conclude that the concentration of large facilities is better compared to a single municipality based facility.展开更多
The drinking water for all the inhabitants of Tangier is still an aim far from being achieved. Therefore, all rural areas and some urban areas feed water wells and springs whose composition and safety are unknown. In ...The drinking water for all the inhabitants of Tangier is still an aim far from being achieved. Therefore, all rural areas and some urban areas feed water wells and springs whose composition and safety are unknown. In the absence of data on water and ignorance of consumers towards the risk of poisoning and waterborne diseases transmitted by these waters, the authors conducted a study to determine the composition, physico-chemical quality and bacteriological these waters. This study is to provide a basic physico-chemical and bacteriological data from these waters in some urban areas of old or missing infrastructure in some sites in the province of Tangier. Such as Ziatine sites, Gzenaya, Rmilate, Malabata + Mnar, Mghoura + Aouama and Downtown. Analyzes are performed according to AFNOR methods (AFNOR: French Standards Association). The results indicate that these waters are generally mild and are experiencing significant geochemical imbalance. Moreover, these waters also have a significant organic and bacteriological pollution. It is concluded that the waters of these sites are of poor quality, unfit for human consumption.展开更多
The target products were prepared by homogeneous precipitation method using SDS and PEG 800, respectively, as surfactant at a reaction temperature of 95 ℃ for 3 h, followed by calcination at 400 ~C for 3 h. The sampl...The target products were prepared by homogeneous precipitation method using SDS and PEG 800, respectively, as surfactant at a reaction temperature of 95 ℃ for 3 h, followed by calcination at 400 ~C for 3 h. The samples were charac- terized and analyzed by XRD, SEM, FTIR and zeta potential measurements. The products were modified with different sur- factants to improve their dispersion stability, both the amount and the best zeta potential values of which were identified in this work. The surface-modified nano-particles were added at a mass fraction of 1.0%, 2.0%, 3.0%, and 4.0%, respectively, into the base oil. It was showed that the additive in base oil has good oil solubility without detectable corrosion of copper stripe, and had excellent behavior in terms of anti-wear performance and lower friction coefficient.展开更多
The recent success in the synthesis and total structure determination of atomically precise gold nanoparticles has provided exciting opportunities for fundamental studies as well as the development of new applications...The recent success in the synthesis and total structure determination of atomically precise gold nanoparticles has provided exciting opportunities for fundamental studies as well as the development of new applications. These unique nanoparticles are of molecular purity and possess well defined formulas (i.e., specific numbers of metal atoms and ligands), resembling organic compounds. Crystallization of such molecularly pure nanoparticles into macroscopic single crystals allows for the determination of total structures of nanoparticles (i.e., the arrangement of metal core atoms and surface ligands) by X-ray crystallography. In this perspective article, we summarize recent efforts in doping and alloying gold nanoparticles with other metals, including Pd, Pt, Ag and Cu. With atomically precise gold nanoparticles, a specific number of foreign atoms (e.g., Pd, Pt) can be incorporated into the gold core, whereas a range of Ag and Cu substitutions is observed but, interestingly, the total number of metal atoms in the homogold nanoparticle is preserved. The heteroatom substitution of gold nanoparticles allows one to probe the optical, structural, and electronic properties truly at the single-atom level, and thus provides a wealth of information for understanding the intriguing properties of this new class of nanomaterials.展开更多
This paper describes the fabrication, characterization and properties of a novel hybrid poly(ethylene glycol) (PEG) based hydrogel via in situ polymerization. The hybrid hydrogel was fabricated by free-radical red...This paper describes the fabrication, characterization and properties of a novel hybrid poly(ethylene glycol) (PEG) based hydrogel via in situ polymerization. The hybrid hydrogel was fabricated by free-radical redox polymerization using ammonium persulfate (APS) and N, N, N/, NCtetramethylethylenediamine (TEMED) as initiators and N, NCmethylene bisacrylamide (BIS) as cross-linker at 60~C. To create a hybrid hydrogel, 0.2% (mass fraction) of MgA1 layered double hydroxide (LDH) was added to the aqueous solution by ultrasonic disper- sion. The physicochemical properties of hybrid hydrogel under vacuum freeze-drying processing were characterized by Fourier transform infrared (FTIR) spectroscopy, thermal gravimetric analysis (TGA) and scanning electron microscopy (SEM), while swelling kinetics and gel content were calculated. Swelling degree in distilled water varied from 94%--125% with a gel mass fraction of 83%--91%. SEM images showed that the micron pore size of hydrogel could be adjusted within the range of several micrometers by changing the cross-linker mass fraction from 2% to 10% (based on glycol). The results showed that the hybrid hydrogels exhibited excellent physicochemical behavior and might be a promising material for applications in tissue engineering and drug delivery.展开更多
基金supported by the National Natural Science Foundation of China (Grant No.41074133)
文摘Missing data are a problem in geophysical surveys, and interpolation and reconstruction of missing data is part of the data processing and interpretation. Based on the sparseness of the geophysical data or the transform domain, we can improve the accuracy and stability of the reconstruction by transforming it to a sparse optimization problem. In this paper, we propose a mathematical model for the sparse reconstruction of data based on the LO-norm minimization. Furthermore, we discuss two types of the approximation algorithm for the LO- norm minimization according to the size and characteristics of the geophysical data: namely, the iteratively reweighted least-squares algorithm and the fast iterative hard thresholding algorithm. Theoretical and numerical analysis showed that applying the iteratively reweighted least-squares algorithm to the reconstruction of potential field data exploits its fast convergence rate, short calculation time, and high precision, whereas the fast iterative hard thresholding algorithm is more suitable for processing seismic data, moreover, its computational efficiency is better than that of the traditional iterative hard thresholding algorithm.
文摘Lubricating mineral base oils are normally extracted from lube-oil cuts with furfural solvent.Aromatic content in the raffinate phase from extraction process is an essential parameter that affects the quality of the lubricating base-oils.For determination of aromatic content by the usual ASTM D3238 method,density,refractive index and molecular weight of the raffinate are required.In this work,a new generalized correlation is developed for de-termination the aromatic content by using only the measured viscosity of lubricating oil.With a mole fraction of aromatic compounds,the kinematic viscosity may be obtained at any temperature between 60-100°C along with their molecular weight and refractive index.
基金Project(2006BAB02A03)supported by the National Key Technology Research and Development ProgramProject(08MX16)supported by Mittal Scientific and Technological Innovation Projects of Central South University during 2008
文摘Physical-chemical properties of phosphorous gypsum, proportion and cemented mechanism of slurry with gypsum as aggregate were studied to remove the harms of gypsum pile, combining with difficult problems of excessive mined-out gobs, enormous ore body under roadway and low recovery ratio of Yongshaba Mine, Kaiyang Phosphor Mine Group, Guizhou Province, China. An appropriate backfill system and craflwork were designed, using shattering milling method to crush gypsum, double-axles mixing and strong activation mixing way to mix slurry, cemented slurry and mullock backfill alternately process. The results show that gypsum is fit for backfilling afterwards by adding fly ash, though it is not an ideal aggregate for fine granule and coagulate retardation. The suggested dosage (the mass ratio of cement to fly ash to gypsum) is 1:1:6-1:1:8 with mass fraction of solid materials 60%-63%. Slurry is transported in suspend state with non-plastic strength, and then in concretion state after backfilling. The application to mine shows the technology is feasible, and gypsum utilization ratio is up to 100%. Transportation and backfill effect is very good for paste-like slurry and drenching cemented slurry into mullock, and the compressive strength and recovery ratio are 2.0 MPa and 82.6%, respectively, with the maximum subsidence of surface only 1.307 mm. Furthermore, the investment of system is about 7 × 10^6 yuan (RMB), only 1/10 of that of traditional paste backfill system.
文摘To facilitate the development of the basis for the selection of plants for re-vegetating tailings in Zambia, an as sessment of the performance of tree species growing on tailings dams was conducted. The performance of species was determined in terms of relative density, frequency and importance value for each species. The study reveals variations in performance of species; for example in terms of importance values, Acacia polyacantha (33.5%), Toona ciliata (21.4%), Acacia sieberana (9.9%), Bauhinia thonningii (9.1%) and Peltophorum africanum (8.3%) were the most dominant species. The dominance of these species on tailings dams demonstrates tolerance to railings dams conditions. The study recommends that emphasis must be placed on these species in re-vegetating tailings dams.
基金Projects(51174253,51304245) supported by National Natural Science Foundation of China
文摘It is of great significance for cleaner production to substitute bio-energy for fossil fuels in iron ore sintering. However, with the replacement ratio increasing, the consistency of heat front and flame front is broken, and the thermal utilizing efficiency of fuel is reduced, which results in the decrease of yield and tumble index of sinter. Circulating flue gas to sintering bed as biochar replacing 40% coke, CO in flue gas can be reused so as to increase the thermal utilizing efficiency of fuels, and the consistency of two fronts is recovered for the circulating flue gas containing certain CO2, H2 O and lower O2, which contributes to increasing the maximum temperature, extending the high temperature duration time of sintering bed, and results in improving the output and quality of sinter. In the condition of circulating 40% flue gas, the sintering with biomass fuels is strengthened, and the sintering indexes with biomass fuel replacing 40% coke breeze are comparative to those of using coke breeze completely.
基金the financial support from the Natural Science Foundation of Chongqing(Project No.cstc2014jcyj A90013)
文摘In order to provide a new way for waste cooking oil(WCO) resource utilization, several diester derivatives were obtained from WCO through a three-step chemical modifications, viz.: transesterification, epoxidation and oxirane ring opening with carboxylic acids. The effects of the chain length of side chain groups on the viscosity, acid value, low temperature fluidity, thermo-oxidative stability, tribological properties and surface tension of diester derivatives were investigated. The results showed that increasing the chain length of side chain groups had a positive influence on the viscosity, viscosity index, acid value, pour point, friction coefficient and wear scar diameter along with a negative influence on the oxidation onset temperature, volatile loss, insoluble deposit, maximum non-seizure load and surface tension. These diester derivatives exhibited improved physicochemical and tribological properties that make themselves promising environmentally friendly biolubricant basestocks.
基金Projects 2006BAB02A03 supported by the National Key Technology Research and Development ProgramProjects 2006BA02B05 by the 11th Five Year Key Program for Science and Technology Development of China
文摘A paste-like self-flowing pipeline transportation backfilling technology with coal gangue as aggregate is proposed to remove the potential damage caused by coal gangue piles. As well, the difficult problems of recovering high quality safety coal pillars and deep mining of the Suncun Coal Mine (SCM), Xinwen Coal Group, Shandong are resolved. The physical-chemical properties of coal gangue, optimized proportion of materials, backfilling system and craft in the SCM were studied in the laboratory and then an industrial test was carried out on high quality coal pillars under a town. The results show that finely crushed kaolinized and fresh gangue with granularity less than 5 mm can be used as aggregate with fly ash to replace part of the cement and a composite water reducer as an additive, accounting for 1.0%-1.5% of the total amount of cement and fly ash. The recommended proportion is l(cement):4(fly ash): 15(coal gangue), with a mass fraction of 72%-75%, rheoiogical paste-like properties and a strength of more than 0.7 MPa at 7 d. The sequence of adding cement, fly ash, water reducer and then coal gangue ensures that the suspended state of the slurry, reducing the wear and jam of pipelines. The working face is advancing continuously by the alternating craft of building block walls with coal gangue and backfilling mined-out gobs with paste-like slurry. The recovery rate is as high as 90% with a backfilling cost of 36.9 YuarffL good utilization of coal gangue and no subsidence on the surface. This technology provides a good theoretical basis and application experience for coal mines, cement backfilling with paste-like slurry.
文摘An experiment was conducted to evaluate the growth performance and cost per gain of Brahman × local crossbred bull calves receiving three diets with varying concentrate to roughage ratio (C:R) of 75:25, 65:35 and 55:45 on dry matter (DM) basis. Twelve bull calves (aging 11.5 ±1.2 months and 170.8 ± 13.0 kg live weight) divided into three equal groups were fed on three diets. The diets were balanced to 14.5% crude protein (CP) level and 10.5 MJ metabolizable energy (ME) per kg DM, formulating different concentrate mixtures. German grass (Echinoclora grousgali) and paddy straw were offered at 2:1 ratio on DM basis as roughages. The results revealed that C:R ratio did not affect (P 〉 0.05) the intake of feed and nutrients, feed efficiency (7.04, 6.94 and 6.76) and average daily gain (981,958 and 976 g). Digestibility of nutrients was not affected (P 〉 0.05) by C:R. Animals fed diet with C:R = 55:45 had the lowest feed cost (Bangladeshi Taka 136.8 BDT/kg live weight gain), which was increased (147.5 B DT and 153.8 BDT) non-significantly (P 〉 0.05) with the increasing level of concentrate. The diet consisting of 55% concentrate mixture showed similar results with the diet consisting of 75% concentrate mixture, but was comparatively economic. Therefore, considering the growth performance and cost per kg gain of Brahman crossbred growing calves, it may be concluded that the diet consisting of 55:45 C:R may be used for economic beef production.
文摘In the past decade,the advent of the epidermal growth factor receptor-tyrosine kinase inhibitors(EGFR-TKIs)has dramatically influenced the therapeutic strategies for treating lung cancer,but with tumor progression and drug resistance,patients will ultimately develop reduced sensitivity to EGFR-TKIs.How can we delay the emergence of drug resistance? What is the next strategy after drug resistance? How to reasonably combine platinum-based chemotherapy and EGFR-TKIs? These questions are currently the focus of lung cancer research.Clinical studies have reported that platinum-based chemotherapy can increase the sensitivity to EGFR-TKIs.However,results of pre-clinical and clinical studies have been inconsistent.The mechanisms of platinum chemotherapy and EGFR-TKIs are still unknown due to the lack of systematic research.Therefore,systematic studies are required to show the mechanisms of EGFR-TKIs and chemotherapy agents and define the markers sensitive to their combinations when given concurrently or sequentially.
文摘Geosciences and statistics were applied to develop predictive models to study the areas of risk to soybean rust (Phakopsora pachyrhizi Sydow) in soybean (Glycine max L.), coffee leaf rust (Hemileia vastatrix Berk & Br) in coffee and Black Sigatoka (Mycosphaerella fijiensis var. difformis) in banana, considering to Brazilian climatic characterization and distribution of soybean, coffee and banana crops in the period of observed data of 1950 to 2000 and A2 climate change scenarios of simulated data of 2020, 2050 and 2080. The technique of principal components allowed generating 1 variable based on 57 variables in order to determine an index explaining 87%, 88% and 90% of the variability of soybean, coffee and banana crops in Brazilian municipal districts. The climatic model of each disease was used to generate the zoning of the coffee rust, soybean rust and black sigatoka based on temperature and leaf wetness. Areas of favorability of the diseases were plotted inside to the main coffee, soybean and banana growing in Brazil. The applied methodology enabled to visualize the variation of favorable areas of epidemics according to the studied scenarios of climate change.
基金supported by the National Science and Technology Program of China Earthquake Administration (No. 2006BAC01B02-01-05)Anhui Provincial Science and Technique Foundation (No. 08010302204)Joint Earthquake Science Fundation (A08077)
文摘Seismic gap method is one of the effective earthquake prediction methods using seismicity patterns. However, this method has some limitations and uncertainty when using it singly in predicting earthquakes. This paper puts forward the prediction method using the dynamic seismicity pattern with dynamic implications. This method considers the formation and evolution of the seismic gap on the basis of plate movement and structural characteristics. Through analysis of 26 cases of earthquakes of MS≥5.0 occurring in East China and South China, this paper obtains the relationship between the main shock with seismic gap and active fault's location, as well as the relationship between the seismic gap and location and strike of active faults. Meanwhile, this paper provides a dynamic explanation of the differences in the formation and evolution patterns of the seismic gap between the two regions, thus providing the physical basis for and reducing the uncertainty of predicting earthquakes using the seismic gap method.
文摘The production of chemicals from biomass is a very challenging process due to its diverse chemical composition. Lignin, cellulose and hemicellulose are the three main biopolymers of wood biomass, with cell walls &plant origin. Lignin has been chosen for the present studies due to its range of different linkages and structures. The present work involved a computational study of the most dominant lignin dimers and their vibrational structures, based on the Density Functional Theory method. Full geometry optimization of the compartments used the StoBe code with cluster model and non-local functional (RPBE) approach. The calculations of the vibrational frequencies were performed with harmonic approximations as well as an anharmonicity fit in the Morse potential function, as implemented in the StoBe code. In the case oflignin, the calculations included three different precursors based on: coumaryl alcohol, coniferyl alcohol and sinapyl alcohol. To represent the cellulose and hemicellulose derivatives, selected aldopentoses and aldohexoses (arabinose, xylose, glucose, galactose, and mannose) were considered. Presented here are the theoretical investigations for a variety of biomass derived compounds, to give the possibility of obtaining a theoretical VBD (Vibrations Basis Database) for experimental spectra interpretation. Such a database could be further used in the preliminary composition assessment of biomass derived substrates, which will be discussed here in more detail.
文摘In Japan, each municipality generally has its own municipal solid waste incineration facilities because of the principle of self-management in the respective territories. Typically, a small municipality often owns a small facility. However, a large facility which can run continuously at high temperature with stability would be preferable if the dioxin generation mechanism is to be considered. Accordingly, municipalities in contiguous areas should cooperate mutually by using a large facility. To evaluate the effect of the concentration of large facilities, the authors created a GIS (Geographic Information System) based database of combustible waste generation at town level in Shizuoka Prefecture. Focusing on large facilities in Shizuoka City and superannuated facilities in Shida area, the authors evaluated the effect of the concentration of large facilities in Shizuoka city on utilization rate of facilities, energy balance and CO2 emissions. Our results showed the amount of light oil consumption and CO2 emissions increased because the mileage distance of garbage collection trucks becomes longer. However, the utilization rates of facilities and the amount of energy recovery from waste are improved. From these standpoints, the authors conclude that the concentration of large facilities is better compared to a single municipality based facility.
文摘The drinking water for all the inhabitants of Tangier is still an aim far from being achieved. Therefore, all rural areas and some urban areas feed water wells and springs whose composition and safety are unknown. In the absence of data on water and ignorance of consumers towards the risk of poisoning and waterborne diseases transmitted by these waters, the authors conducted a study to determine the composition, physico-chemical quality and bacteriological these waters. This study is to provide a basic physico-chemical and bacteriological data from these waters in some urban areas of old or missing infrastructure in some sites in the province of Tangier. Such as Ziatine sites, Gzenaya, Rmilate, Malabata + Mnar, Mghoura + Aouama and Downtown. Analyzes are performed according to AFNOR methods (AFNOR: French Standards Association). The results indicate that these waters are generally mild and are experiencing significant geochemical imbalance. Moreover, these waters also have a significant organic and bacteriological pollution. It is concluded that the waters of these sites are of poor quality, unfit for human consumption.
基金supported by the Liaoning Provincial Office of Education for Innovation Team (2006T001)Liaoning Province of Key Laboratory Project (2008403001)
文摘The target products were prepared by homogeneous precipitation method using SDS and PEG 800, respectively, as surfactant at a reaction temperature of 95 ℃ for 3 h, followed by calcination at 400 ~C for 3 h. The samples were charac- terized and analyzed by XRD, SEM, FTIR and zeta potential measurements. The products were modified with different sur- factants to improve their dispersion stability, both the amount and the best zeta potential values of which were identified in this work. The surface-modified nano-particles were added at a mass fraction of 1.0%, 2.0%, 3.0%, and 4.0%, respectively, into the base oil. It was showed that the additive in base oil has good oil solubility without detectable corrosion of copper stripe, and had excellent behavior in terms of anti-wear performance and lower friction coefficient.
文摘The recent success in the synthesis and total structure determination of atomically precise gold nanoparticles has provided exciting opportunities for fundamental studies as well as the development of new applications. These unique nanoparticles are of molecular purity and possess well defined formulas (i.e., specific numbers of metal atoms and ligands), resembling organic compounds. Crystallization of such molecularly pure nanoparticles into macroscopic single crystals allows for the determination of total structures of nanoparticles (i.e., the arrangement of metal core atoms and surface ligands) by X-ray crystallography. In this perspective article, we summarize recent efforts in doping and alloying gold nanoparticles with other metals, including Pd, Pt, Ag and Cu. With atomically precise gold nanoparticles, a specific number of foreign atoms (e.g., Pd, Pt) can be incorporated into the gold core, whereas a range of Ag and Cu substitutions is observed but, interestingly, the total number of metal atoms in the homogold nanoparticle is preserved. The heteroatom substitution of gold nanoparticles allows one to probe the optical, structural, and electronic properties truly at the single-atom level, and thus provides a wealth of information for understanding the intriguing properties of this new class of nanomaterials.
基金the National Natural Science Foundation of China(No.31000427)the China Postdoctoral Science Foundation(No.20100481214)the Fundamental Research Funds for the Central Universities of China(Nos.2012QN052 and 2012TD013)
文摘This paper describes the fabrication, characterization and properties of a novel hybrid poly(ethylene glycol) (PEG) based hydrogel via in situ polymerization. The hybrid hydrogel was fabricated by free-radical redox polymerization using ammonium persulfate (APS) and N, N, N/, NCtetramethylethylenediamine (TEMED) as initiators and N, NCmethylene bisacrylamide (BIS) as cross-linker at 60~C. To create a hybrid hydrogel, 0.2% (mass fraction) of MgA1 layered double hydroxide (LDH) was added to the aqueous solution by ultrasonic disper- sion. The physicochemical properties of hybrid hydrogel under vacuum freeze-drying processing were characterized by Fourier transform infrared (FTIR) spectroscopy, thermal gravimetric analysis (TGA) and scanning electron microscopy (SEM), while swelling kinetics and gel content were calculated. Swelling degree in distilled water varied from 94%--125% with a gel mass fraction of 83%--91%. SEM images showed that the micron pore size of hydrogel could be adjusted within the range of several micrometers by changing the cross-linker mass fraction from 2% to 10% (based on glycol). The results showed that the hybrid hydrogels exhibited excellent physicochemical behavior and might be a promising material for applications in tissue engineering and drug delivery.