高碳量助燃式造气煤球的研制及应用

高碳量助燃式造气煤球的研制及应用汪敬恒许志华（河南省化工研究所郑州４５００５２）１前言我国小氮肥厂、印染厂、玻璃厂、双氧水厂等企业，主要用无烟煤来造气，而无烟煤在从开采到入炉的整个过程中，要产生大量的无法直接用来造气的煤末，只能廉价卖出，或用作燃料煤...

氮碳共渗高碳当量灰铸铁摩擦学特性研究

对高碳当量灰铸铁进行了低温氮碳共渗处理,考察了干滑动摩擦条件下不同载荷和摩擦时间对未处理高碳当量灰铸铁和氮碳共渗高碳当量灰铸铁的滑动摩擦学特性影响.研究结果表明:未处理高碳当量灰铸铁在不同载荷下的磨损类型均为黏着磨损,低载荷下伴有轻微的磨粒磨损,高载荷下则伴有严重的磨粒磨损;氮碳共渗高碳当量灰铸铁在低载荷下的磨损为轻微的黏着磨损,高载荷下除了黏着磨损外还伴有轻微的磨粒磨损.

高含碳量粉煤灰混凝土

一、贵州地区粉煤灰情况简介贵州省是我国十大产煤区之一。燃煤大量用于火力发电,粉煤灰年湿排量50多万吨。一些主要电厂排出的粉煤灰化学成分分析如表—1(%),由表—1可以看出,贵州粉煤灰的特点是烧失量很大,即含碳量特高。远远超过国家标准《用于水泥和砼中的粉煤灰》GB1596—79中烧失量不得超过8%的技术指标。若按《粉煤灰在砼和砂浆中应用技术规程》(以后简称“规程”)

Effect of carbon addition on carbide morphology of single crystal Ni-based superalloy

Single crystal superalloys of AM3 with different carbon levels were prepared at withdraw rate of 50μm/s. The effect of carbon addition on the carbide morphology was investigated. It was found that there were four types of MC-type carbides, acicular, nodular, blocky, and Chinese script-type in the crystals. With an increase in carbon level, the volume fraction of carbide increased significantly while the volume fraction of eutectic decreased significantly. Furthermore, the size of carbide in high level carbon alloy became much larger.

Carbon storage and flux for alpine tundra ecosystems in Changbai Mountains,Northeast China

This paper examined the carbon storage and flux of vegetation-litter-soil in alpine tundra ecosystems in Changbai Mountains. Approximately 17251 t·a-1 of carbon was yearly stored in the vegetation and 15043.1 t·a^-1of carbon flew into soil by litters. The vegetation-litter-soil ecosystem stored 452624 t·a^-1 of carbon, which was the important CO2 sink. The net carbon storage was currently 3146 t·a^-1 in vegetation-litter-soil ecosystem.

Spatial pattern of soil carbon and nutrient storage at the Alpine tun-dra ecosystem of Changbai Mountain, China

In August 2003, we investigated spatial pattern in soil carbon and nutrients in the Alpine tundra of Changbai Moun-tain, Jilin Province, China. The analytical results showed that the soil C concentrations at different depths were significantly (p<0.05) higher in Meadow alpine tundra vegetation than that in other vegetation types; the soil C (including inorganic carbon) concentrations at layer below 10 cm are significantly (p<0.05) higher than at layer of 1020 cm among the different vegetation types; the spatial distribution of soil N concentration at top surface of 0-10 cm depth was similar to that at 1020 cm; the soil P concentrations at different depths were significantly (p<0.05) lower at Lithic alpine tundra vegetation than that at other vegetation types; soil K concentration was significantly (p<0.05) higher in Felsenmeer alpine tundra vegetation and Lithic alpine tundra vegetation than that in Typical alpine tundra, Meadow alpine tundra, and Swamp alpine tundra vegetations.. However, the soil K had not significant change at different soil depths of each vegetation type. Soil S concentration was dramatically higher in Meadow alpine tundra vegetation than that in other vegetation types. For each vegetation type, the ratios of C: N, C: P, C: K and C: S generally decreased with soil depth. The ratio of C: N was significantly higher at 010 cm than that at 1020 cm for all vegetation types except at the top layer of the Swamp alpine tundra vegetation. Our study showed that soil C and nutrients storage were significantly spatial heterogeneity.

Soil Carbon Stock and Flux in Plantation Forest and Grassland Ecosystems in Loess Plateau, China

Carbon sequestration occurs when cultivated soils are re-vegetated. In the hilly area of the Loess Plateau, China, black locust （Robinia pseudoacacia） plantation forest and grassland were the two main vegetation types used to mitigate soil and water loss after cultivation abandonment. The purpose of this study was to compare the soil carbon stock and flux of these two types of vegetation which restored for 25 years. The experiment was conducted in Yangjuangou catchment in Yah＇an City, Shaanxi Province, China. Two adjacent slopes were chosen for this study. Six sample sites were spaced every 35-45 m from summit to toe slope along the hill slope, and each sample site contained three sampling plots. Soil organic carbon and related physicochemical properties in the surface soil layer （0-10 cm and 10-20 cm） were measured based on soil sampling and laboratory analysis, and the soil carbon dioxide （CO2） emissions and environmental factors were measured in the same sample sites simultaneously. Results indicated that in general, a higher soil carbon stock was found in the black locust plantation forest than that in grassland throughout the hill slope. Meanwhile, significant differences in the soil carbon stock were observed between these two vegetation types in the upper slope at soil depth 0-10 cm and lower slope at soil depth 10-20 cm. The average daily values of the soil CO2 emissions were 1.27 μmol/（m2·s） and 1.39 μmol/（m2·s） for forest and grassland, respectively. The soil carbon flux in forest covered areas was higher in spring and less variation was detected between different seasons, while the highest carbon flux was found in grassland in summer, which was about three times higher than that in autumn and spring. From the carbon sequestration point of view, black locust plantation forest on hill slopes might be better than grassland because of a higher soil carbon stock and lower carbon flux.

Reduction of Cr(Ⅵ) with a relative high concentration using different kinds of zero-valent iron powders: Focusing on effect of carbon content and structure on reducibility

Reduction of Cr(VI)using zero-valent iron(ZVI)could not only decrease the amounts of chemicals used for reduction,but also decrease the discharge of sludge.In order to find a desirable ZVI material,reduction of Cr(VI)with a relative high concentration using different kinds of ZVI powders(mainly carbon differences)including reduced Fe,grey cast iron,pig iron,nodular pig iron was carried out.Parameters such as ZVI dosage,type and size affecting on Cr(VI)reduction were firstly examined and grey cast iron was selected as a preferable reducing material,followed by pig iron.Additionally,it was found that the parameters had significant influences on experimental kinetics.Then,morphology and composition of the sample before and after reaction were characterized by SEM,EPMA and XPS analyses to disclose carbon effect on the reducibility.In order to further interpret reaction mechanism,different reaction models were constructed.It was revealed that not only the carbon content could affect the Cr(VI)reduction,but also the carbon structure had an important effect on its reduction.

Difference in Organic Carbon Contents and Distributions in Particle-size Fractions between Soil and Sediment on the Southern Loess Plateau, China

The purpose of this study was to assess the effect of long-term cultivation and water erosion on the soil organic carbon （OC） in particle-size fractions. The study site is located at Nihegou Watershed in the Southern Loess Plateau, China. The soil at this site is loess with loose and silty structure, and contains macropores. The results showed that the OC concentrations in sediments and in the particle-size fractions of sediments were higher than those in soils and in the particle-size fractions of soils. The OC concentration was highest in the clay particles and was lowest in the sand particles. Clay particles possessed higher OC enrichment ability than silt and sand particles. The proportions of OC in the silt fractions of soil and sediment were the highest （mean value of 53.87% and 58.48%, respectively）, and the total proportion of OC in the clay and silt fractions accounted for 96% and 98% of the total OC in the soil and sediment, respectively. The loss of OC was highest in silt particles, with an average value of 0.16 Mg ha^-1 y^-1, and was lowest in the sand （0.003 Mg ha^-1 y^-l）. This result suggests that the fine particle-size fraction in the removed sediment may be an important indicator to assess soil OC losses.

Research on the Soil Carbon Storage of Alpine Grassland under Different Land Uses in Qinghai-Tibet Plateau

In this article, we mainly analysis the soil carbon storage of the alpine grassland under different land uses in Qinghai-Tibet Plateau. The samples of this investigation include six experimental fields which are fenced mowing grassland, artificial grassland, winter and spring grazing meadowland, summer and autumn mild grazing land, summer and autumn moderate grazing pasture and summer and autumn severe grazing land and seven soil layers included 0 cm-5 cm, 5 cm-10 cm, 10 cm-20 cm, 20 cm-30 cm, 30 cm-50 cm, 50 cm-70 cm and 70 cm-100 cm. The results show that the soil carbon storage in different soil layers will gradually reduce and the difference was remarkable （P 〈 0.05）. What is more, the soil carbon storage of alpine grassland under different land uses has following sequence： winter and spring grazing grassland 〉 summer and autumn mild grazing land 〉 artificial grassland 〉 summer and autumn moderate grazing meadowland 〉 summer and autumn severe grazing pasture 〉 fenced mowing meadow, and the significant difference between them is remarkable （P 〈 0.05）.

Effect of carbon on microstructure of CrAlC_xN_(1-x) coatings by hybrid coating system

A systematic investigation of the microstructure of CrA1CxN1-x coatings as a function of carbon contents was conducted. Quaternary CrA1CxN1-x coatings were deposited on Si wafers by a hybrid coating system combining an arc-ion plating technique and a DC reactive magnetron sputtering technique using Cr and AI targets in the Ar/N2/CH4 gaseous mixture. The effect of carbon content on microstructure of CrA1C^N~ x coatings was investigated with instrumental analyses of X-ray diffraction, X-ray photoelectron, and high-resolution transmission electron microscopy. The results show that the carbon content of CrA1CxN1-x coatings linearly increases with increasing CH4/（CH4/N2） gas flow rate ratio. The surface roughness of the CrA1CxN1-x coating layer decreases with the increase of carbon content.

Decomposition and Products of Wheat and Rice Straw from a FACE Experiment Under Flooded Conditions

Winter wheat and rice straw produced under ambient and elevated CO2 in a China rice-wheat rotation free-air CO2 enrichment （FACE） experiment was mixed with a paddy soil at a rate of 10 g kg^-1 （air-dried）, and the mixture was incubated under flooded conditions at 25℃ to examine the differences in decomposition as well as the products of crop residues produced under elevated CO2. Results showed that the C/N ratio and the amount of soluble fraction in the amended rice straw grown under elevated CO2 （FR） were 9.8% and 73.1% greater, and the cellulose and lignin were 16.0% and 9.9% lesser than those of the amended rice straw grown under ambient CO2 （AR）, respectively. Compared with those of the AR treatment, the CO2-C and CH4-C emissions in the FR treatment for 25 d were increased by 7.9% and 25.0%, respectively; a higher ratio of CH4 to CO2 emissions induced by straw in the FR treatment was also observed. In contrast, in the treatments with winter wheat straw, the CO2-C and CH4-C emissions, the ratio of straw-induced CH4 to CO2 emissions, and the straw composition were not significantly affected by elevated CO2, except for an 8.0% decrease in total N and a 9.7% increase in C/N ratio in the wheat straw grown under elevated CO2. Correlation analysis showed that the net CO2-C and CH4-C emission from straw and the ratio of straw-induced CH4 to CO2 emissions were all exponentially related to the amount of soluble fraction in the amended straw （P 〈0.05）. These indicated that under flooded conditions, the turnover and CH4 emission from crop straw incorporated into soil were dependent on the effect of elevated CO2 on straw composition, and varied with crop species. Incorporation of rice straw grown under elevated CO2 would stimulate CH4 emission from flooded rice fields, whereas winter wheat straw grown under elevated CO2 had no effect on CH4 emission.

Soil Organic Carbon and Nutrients along an Alpine Grassland Transect across Northern Tibet

Soil carbon and nutrient contents and their importance in advancing our understanding of biogeochemical cycling in terrestrial ecosystem, has motivated ecologists to find their spatial patterns in various geographical area. Few studies have focused on changes in the physical and chemical properties of soils at high altitudes. Our aim was to identify the spatial distribution of soil physical and chemical properties in cold and arid climatic region. We also tried to explore relationship between soil organic carbon （SOC） and total nitrogen （TN）, total phosphorus （TP）, available nitrogen （AN）, available phosphorus （AP）, soil particle size distribution （PSD）. Samples were collected at 44 sites along a 300 km transect across the alpine grassland of northern Tibet. The study results showed that grassland type was the main factor influencing SOC, TN and TP distribution along the Gangdise Mountain-Shenzha-Shuanghu Transect. SOC, TN and TP contents were significantly higher in alpine meadow than alpine steppe ecosystems. SOC, TN, TP and AN contents in two soil layers （0-15 cm and 15-3o cm） showed no significant differences, while AP content in top soft （0-15 cm） was significantly higher than that in sub-top soil （15-30cm）. SOC content was correlated positively with TN and TP content （r = 0.901and 0.510, respectively）. No correlations were detected for clay content and fractal dimension of particle size distribution （D）. Our study results indicated the effects of vegetation on soil C, N and P seem to be more important than that of rocks itself along latitude gradient on the northern Tibetan Plateau. However, we did not found similar impacts of vegetation on soil properties in depth. Inaddition, this study also provided an interesting contribution to the global data pool on soil carbon stocks.

The Utilization of Real-Time High Resolution Monitoring Techniques in Karst Carbon Sequestration:A Case Study of the Station in Banzhai Subterranean Stream Catchment

The karst process acts as carbon sequestration for atmospheric CO_2.The amount of karst carbon sequestration (KCS) depends on the discharge of karst catchment and inorganic carbon concentration of the water body.Based on the data from the monitoring station on Banzhai subterranean stream located in Maolan National Nature Reserve of Guizhou province,the process and influence factors of KCS have been analyzed.It shows that the amount of KCS is about 353 t C per year in the catchment of Banzhai subterranean stream,and there is good linear relationship between the strength of KCS and discharge of the stream at various time scales.Therefore,how to monitor the discharge accurately is the key to the estimation of KCS.And stations with real-time monitoring function are very important for KCS calculation because of strong seasonal variability of the karst water cycle.

Relationship Between Microbial Community and Soil Properties During Natural Succession of Abandoned Agricultural Land

The changes of microbial biomass carbon (MBC) and nitrogen (MBN) and microbial community in the topsoil of the abandoned agricultural land on the semi-arid Loess Plateau in China during the natural succession were evaluated to understand the relationship between microbial community and soil properties. MBC and MBN were measured using fumigation extraction, and microbial community was analyzed by the method of fatty acid methyl ester (FAME). The contents of organic C, total N, MBC, MBN, total FAME, fungal FAME, bacterial FAME and Gram-negative bacterial FAME at the natural succession sites were higher than those of the agricultural land, but lower than those of the natural vegetation sites. The MBC, MBN and total FAME were closely correlated with organic C and total N. Furthermore, organic C and total N were found to be positively correlated with fungal FAME, bacterial FAME, fungal/bacterial and Gram-negative bacterial FAME. Natural succession would be useful for improving soil microbial properties and might be an important alternative for sustaining soil quality on the semi-arid Loess Plateau in China.

In-situ Polymerization-modification Process and Foaming of Poly（ethylene terephthalate）

Most of traditional linear poly(ethylene terephthalate)(PET)resins of relatively low molecular mass and narrow molecular mass distribution have low melt strength at foaming temperatures,which are not enough to support and keep cells.An in-situ polymerization-modification process with esterification and polycondensation stages was performed in a 2 L batch stirred reactor using pyromellitic dianhydride(PMDA)or pentaerythritol(PENTA)as modifying monomers to obtain PETs with high melt strength.The influence of amounts of modifying monomers on the properties of modified PET was investigated.It was found that the selected modifying monomers could effectively introduce branched structures into the modified PETs and improve their melt strength.With increasing the amount of the modifying monomer,the melt strength of the modified PET increased.But when the amount of PENTA reached 0.35%or PMDA reached 0.9%,crosslinking phenomenon was observed in the modified PET.Supercritical carbon dioxide(ScCO2)was employed as physical foaming agent to evaluate the foaming ability of modified PETs.The modified PETs had good foaming properties at 14 MPa of CO2pressure with foaming temperature ranging from 265°C to 280°C.SEM micrographs demonstrated that both modified PET foams had homogeneous cellular structures,with cell diameter ranging from 35μm to 49μm for PENTA modified PETs and38μm to 57μm for PMDA modified ones.Correspondingly,the cell density had a range of 3.5×107cells·cm 3to 7×106cells·cm 3for the former and 2.8×107cells·cm 3to 5.8×106cells·cm 3for the latter.

Nitrogen Recoveries and Yields Improvement in Cowpea sorghum and Fallow sorghum Rotations in West Africa Savannah

The effects of previous cowpea （Vignaunguiculata） and annual fallow on N recoveries, succeeding sorghum yields and soil properties were studied using a 5-year-old （1995-1999） field experiment at Kouar6 （11°59′ North, 0°19′ West and 850 m altitude） in Burkina Faso. A 3 4 factorial design in a split plot arrangement with three rotation treatments and four fertilizer treatments was used. Total N uptake by succeeding sorghum increased from 26 kg N ha~ in mono cropping of sorghum to 31 and 48 kg N ha~ when sorghum was rotated with fallow or cowpea respectively. Nitrogen derived from fertilizer increased from 10% in mono cropping of sorghum to 22% and 26% when sorghum was rotated with fallow or cowpea respectively. While fallow did not increase N derived from soil, cowpea doubled the quantity of N derived from soil （Ndfs）. Sorghum grain yields increased from 75% and 100% when sorghum was rotated with fallow or cowpea respectively. All rotations treatments decreased soil organic C and N but soil organic C was the highest in fallow-sorghum rotation. It was concluded that cowpea-sorghum rotation was more effective than fallow-sorghum rotation and five management options were suggested to improve traditional system productivity.

Sorption and Diffusion Behavior of Carbon Dioxide into Poly（l-lactic acid） Films at Elevated Pressures

Equilibrium sorption amount, desorption diffusion coefficients and sorption diffusion coefficients of CO2 in poly（l-lactic acid） （PLLA） films at elevated pressures were determined by the gravimetric method, in which the Fick＇s diffusion model was applied to analyze both the desorption and sorption processes. The equilibrium sorption amount of CO2 in PLLA increased with lowering temperature and elevating pressure at the temperature range from 40 to 60 ℃ and pressure from 10^4 to 2x10^4 kPa. Desorption diffusion coefficients were greatly influenced by the equilibrium sorption amount, and they were in the same order of magnitude as the sorption diffusion coefficients. The scan electron microscope （SEM） photos demonstrated that there was no foaming phenomenon of the PLLA film during desorption and sorption processes. The XRD spectra implied that the crystalline degree of PLLA film decreased after CO2 processing. It was concluded that PLLA polymer could be well swollen and plasticized by supercritical CO2.

Increased working voltage of hexamine-coated porous carbon for supercapacitors

Highly porous carbon, both unmodified and hexamine-coated on the pore surfaces, is tested at high working voltages in organic electrolyte for supercapacitors in order to enhance the energy density and power density.Sol–gel processing allows for excellent control of the porous structure and chemical composition of carbon,resulting in a material with high surface area and a low level of impurities. This porous carbon can be modified using a simple solution-based method to enhance capacitance. Increasing the working voltage from 2.0 to 3.0 V significantly improves performance for both unmodified and hexamine-coated carbon. The energy density and power density increase at higher working voltage, and under certain conditions, the capacitance increases as well.Cyclic stability is also investigated, with hexamine-coated carbon retaining more of its initial capacitance than unmodified carbon at all working voltages.

Plum pudding model inspired KVPO4F@3DC as high-voltage and hyperstable cathode for potassium ion batteries

The investigation on the cathode material of potassium ion batteries(PIBs),one of the most promising alternatives to lithium ion batteries,is of great significance.Potassium vanadium fluorophosphate(KVPO4F)with a high working voltage is an appealing cathode candidate for PIBs,while the poor cycling performance and low electronic conductivity dramatically hinder the application.Herein,a plum pudding model inspired three-dimensional amorphous carbon network modified KVPO4F composite(KVPO4F@3DC)is successfully designed in this study to tackle these problems.In the composite,KVPO4F particles are homogeneously wrapped by a layer of amorphous carbon and bridged by crosslinked large area carbon sheets.As the cathode for PIBs,the KVPO4F@3DC composite exhibits a high average operating voltage about 4.10 V with a super-high discharge capacity of 102.96 mAh g^-1 at 20 mA g^-1.An excellent long cycle stability with a capacity retention of 85.4%over 550 cycles at 500 mA g^-1 is achieved.In addition,it maintains 83.6%of its initial capacity at 50 mA g^-1 after 100 cycles at 55℃.The design of KVPO4F@3DC with plum pudding structure provides facilitative electron conductive network and stable electrode/electrode interface for electrode,successfully innovating an ultra-stable and high-performance cathode material for potassium ion batteries.