Conventional mechanical method and mechanical method combined with vacuum freeze-drying technology were used to make the ultra-fine powders of edible fungus (Auricularia auricular). The content of basic nutrients, ami...Conventional mechanical method and mechanical method combined with vacuum freeze-drying technology were used to make the ultra-fine powders of edible fungus (Auricularia auricular). The content of basic nutrients, amino acid, micro structure and their properties of raw edible fungus and the edible fungus powders obtained with the two methods were analyzed and compared. The granularity size and micro-structure of the pulverized samples were analyzed by SEM and TEM technology. The average granularity size of the edible fungus powder obtained with mechanical method was 1–5 μm, while that obtained with mechanical method combined with vacuum freeze-drying process was 0.5–1 μm. The ultra-fine powders of edible fungus obtained with the two methods had better water recovery capability and quality, and their preserving time was longer than that of raw edible fungus. All the properties of the ultra-fine powders of edible fungus obtained with the vacuum freeze-drying technology were evidently superior to that of the conventional mechanical method. Keywords Auricularia auricula - Edible fungus - Ultra-fine powders - Vacuum freeze-drying CLC number TS205 Document code B Biography: YANG Chun-yu (1975), female, Ph. D. in Engineering Technology Center of Forestry and Wood Workine, Machinery, Northeast Forestry University, Harbin 150040, P. R. China.Responsible editor: Zhu Hong展开更多
Chinese bamboo flour was chemically modified by acetylation with acetic anhydride by using trichloroacetic acid as an activation agent and the optimized condition for acetylation of bamboo flour was determined as the ...Chinese bamboo flour was chemically modified by acetylation with acetic anhydride by using trichloroacetic acid as an activation agent and the optimized condition for acetylation of bamboo flour was determined as the trichloroacetic acid amount 6.0 g per 1.5-g bamboo flour, ultrasosonication duration 40 min and the reaction time 1 h at 65℃. The composition, microstructure and thermal behavior of acetylated bamboo flour were preliminarily characterized by FT-IR, DSC and SEM etc. The acetylated bamboo flour can be molded into sheets at 130℃ and 10 MPa, indicating the modified bamboo flour possesses thermalplastic performance.展开更多
In order to effectively control the dust in the underground coal mine,this study proposes and develops a new technology for dust control by foam,and briefly demonstrates the advantage of the foam technology for dust c...In order to effectively control the dust in the underground coal mine,this study proposes and develops a new technology for dust control by foam,and briefly demonstrates the advantage of the foam technology for dust control,such as the good isolation performance,large contact area,high wetting ability,strong adhesion and so on.Besides,the details of the technology are introduced,including the foam agent,foam generator,and foam production process.Then the paper studies the relationship between the foaming agent concentration and liquid surface tension,and explains the principle of the foam generator.The technology is applied in heading face.The application results show that the foam has a remarkable effect on dust control in underground coal mines.展开更多
After gas drainage, the outburst seam is dry and, consequently, during subsequent mechanized mining, unwanted dust production is extensive. Because the hard dustfall typically has a small particle size it contains a h...After gas drainage, the outburst seam is dry and, consequently, during subsequent mechanized mining, unwanted dust production is extensive. Because the hard dustfall typically has a small particle size it contains a high percentage of respirable dust. Considering these factors, this paper improved the efficiency of dustfall by reducing the surface tension of the liquid used as a wetting agent, then configuring five kinds of wetting agents by adopting various doses and types of surfactants, neutral inorganic salts and chemical additives, etc. After purchasing DA-85 and SRJ-1 wetting agent, the surface tension and critical micelle concentration of seven kinds of wetting agents were measured using the capillary rise method. Wetting agent A was confirmed to have the best comprehensive effect. The experiments were optimized by measuring and comparatively analyzing contact angles of pure water, SRJ-1 wetting agent and wetting agent A on the surface of different coal samples using a contact angle measurement instrument （HARKE- SPCA）. By comparative analysis, dust-proof effects of seam, dynamic pressure water infusion and high- pressure spray in the tunneling face at the Daning coal mine using pure water, wetting agent SRJ-1 and A, it was determined that after using wetting agent A, the average dust concentration in the place of the mining machine driver, 10 m and 110 m away from the tunneling front is approximately 300 rag/ m^3, 240 mg/m^3 and 100 mg/m^3, respectively, This practice increased the dust-proof efficiency dramati- cally and achieved a good comprehensive dust-proof effect.展开更多
Influence of ultrafine active mineral (DK mineral) on mechanical property of fly ash based load bearing aerocrete was analyzed. The result shows that the addition of DK mineral in a suitable amount can enhance obvious...Influence of ultrafine active mineral (DK mineral) on mechanical property of fly ash based load bearing aerocrete was analyzed. The result shows that the addition of DK mineral in a suitable amount can enhance obviously the compressive strength of aerocrete. According to the SEM EDS and X ray diffraction analyses, the crystal shapes of hydration products are well developed and interlocked for samples containing DK mineral. Its microstructure is denser than that of the samples without DK mineral. Having a good activation, the DK mineral makes both the type and the quantity of hydrated products be obviously superior to that of the contrast sample.展开更多
At a fully mechanized working face of a coal mine as prototype,we investigated,by simulation,the flow field and dust distribution during the process of its isolation by a curtain of air,using the CFD software, Fluent....At a fully mechanized working face of a coal mine as prototype,we investigated,by simulation,the flow field and dust distribution during the process of its isolation by a curtain of air,using the CFD software, Fluent.The results show that the air curtain installed on the shearer can effectively prevent the dust （especially the respirable dust）from diffusing into the work area of the operator,reducing the dust concentration on the side of the operator and greatly improving his working environment.The field application of the air curtain shows that the dust-isolation effect of an air curtain is quite noticeable.The isolation efficiency for respiratory dust is over 70%and,as well,it has good dust-isolation effect for nonrespiratory dust.The air curtain is a useful way to resolve the problem of dust-isolation at a fully mechanized working face.It has a practical background elsewhere with more extensive applications.展开更多
Gas-solid two-phase flow theory was used to predict dust distribution and movement at the working face of a mine.The software package FLUENT was used to numerically simulate dust motion and the results were compared t...Gas-solid two-phase flow theory was used to predict dust distribution and movement at the working face of a mine.The software package FLUENT was used to numerically simulate dust motion and the results were compared to observed data.The simulation agrees with the data taken from an actual working face,which confirms the choice of mathematical model and numerical simulation method. Using the model we predict a set of conditions optimum for reducing dust concentrations at the mine working face.展开更多
文摘Conventional mechanical method and mechanical method combined with vacuum freeze-drying technology were used to make the ultra-fine powders of edible fungus (Auricularia auricular). The content of basic nutrients, amino acid, micro structure and their properties of raw edible fungus and the edible fungus powders obtained with the two methods were analyzed and compared. The granularity size and micro-structure of the pulverized samples were analyzed by SEM and TEM technology. The average granularity size of the edible fungus powder obtained with mechanical method was 1–5 μm, while that obtained with mechanical method combined with vacuum freeze-drying process was 0.5–1 μm. The ultra-fine powders of edible fungus obtained with the two methods had better water recovery capability and quality, and their preserving time was longer than that of raw edible fungus. All the properties of the ultra-fine powders of edible fungus obtained with the vacuum freeze-drying technology were evidently superior to that of the conventional mechanical method. Keywords Auricularia auricula - Edible fungus - Ultra-fine powders - Vacuum freeze-drying CLC number TS205 Document code B Biography: YANG Chun-yu (1975), female, Ph. D. in Engineering Technology Center of Forestry and Wood Workine, Machinery, Northeast Forestry University, Harbin 150040, P. R. China.Responsible editor: Zhu Hong
基金Fujian Province science and technology office (2007F5030)(in part) National Natural Scince Foundation of China (grant 50473063)
文摘Chinese bamboo flour was chemically modified by acetylation with acetic anhydride by using trichloroacetic acid as an activation agent and the optimized condition for acetylation of bamboo flour was determined as the trichloroacetic acid amount 6.0 g per 1.5-g bamboo flour, ultrasosonication duration 40 min and the reaction time 1 h at 65℃. The composition, microstructure and thermal behavior of acetylated bamboo flour were preliminarily characterized by FT-IR, DSC and SEM etc. The acetylated bamboo flour can be molded into sheets at 130℃ and 10 MPa, indicating the modified bamboo flour possesses thermalplastic performance.
基金The financial support by the National Natural Science Foundation of China (No.51104153)the Fundamental Research Fundsfor the Central Universities (No.2011QNB11)
文摘In order to effectively control the dust in the underground coal mine,this study proposes and develops a new technology for dust control by foam,and briefly demonstrates the advantage of the foam technology for dust control,such as the good isolation performance,large contact area,high wetting ability,strong adhesion and so on.Besides,the details of the technology are introduced,including the foam agent,foam generator,and foam production process.Then the paper studies the relationship between the foaming agent concentration and liquid surface tension,and explains the principle of the foam generator.The technology is applied in heading face.The application results show that the foam has a remarkable effect on dust control in underground coal mines.
基金partly supported by the National Natural Science Foundation of China (No.51404263)the National Natural Science Foundation of Jiangsu Province (No.BK20130203)+3 种基金the Coal Mine Joint Funds of the National Natural Science Foundation of China (No.51134023)the State Key Laboratory Cultivation Base for Gas Geology and Gas Control (No.WS2013A05)the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)the independent study for State Key Laboratory of Coal Resources and Safe Mining,China University of Mining and Technology (No.SKLCRSM09X04)
文摘After gas drainage, the outburst seam is dry and, consequently, during subsequent mechanized mining, unwanted dust production is extensive. Because the hard dustfall typically has a small particle size it contains a high percentage of respirable dust. Considering these factors, this paper improved the efficiency of dustfall by reducing the surface tension of the liquid used as a wetting agent, then configuring five kinds of wetting agents by adopting various doses and types of surfactants, neutral inorganic salts and chemical additives, etc. After purchasing DA-85 and SRJ-1 wetting agent, the surface tension and critical micelle concentration of seven kinds of wetting agents were measured using the capillary rise method. Wetting agent A was confirmed to have the best comprehensive effect. The experiments were optimized by measuring and comparatively analyzing contact angles of pure water, SRJ-1 wetting agent and wetting agent A on the surface of different coal samples using a contact angle measurement instrument （HARKE- SPCA）. By comparative analysis, dust-proof effects of seam, dynamic pressure water infusion and high- pressure spray in the tunneling face at the Daning coal mine using pure water, wetting agent SRJ-1 and A, it was determined that after using wetting agent A, the average dust concentration in the place of the mining machine driver, 10 m and 110 m away from the tunneling front is approximately 300 rag/ m^3, 240 mg/m^3 and 100 mg/m^3, respectively, This practice increased the dust-proof efficiency dramati- cally and achieved a good comprehensive dust-proof effect.
文摘Influence of ultrafine active mineral (DK mineral) on mechanical property of fly ash based load bearing aerocrete was analyzed. The result shows that the addition of DK mineral in a suitable amount can enhance obviously the compressive strength of aerocrete. According to the SEM EDS and X ray diffraction analyses, the crystal shapes of hydration products are well developed and interlocked for samples containing DK mineral. Its microstructure is denser than that of the samples without DK mineral. Having a good activation, the DK mineral makes both the type and the quantity of hydrated products be obviously superior to that of the contrast sample.
基金Financial support for this work,provided by the National Natural Science Foundation of China(No.50974060)the State Safety Production Science and Technology Development Plan (No.06-396)
文摘At a fully mechanized working face of a coal mine as prototype,we investigated,by simulation,the flow field and dust distribution during the process of its isolation by a curtain of air,using the CFD software, Fluent.The results show that the air curtain installed on the shearer can effectively prevent the dust （especially the respirable dust）from diffusing into the work area of the operator,reducing the dust concentration on the side of the operator and greatly improving his working environment.The field application of the air curtain shows that the dust-isolation effect of an air curtain is quite noticeable.The isolation efficiency for respiratory dust is over 70%and,as well,it has good dust-isolation effect for nonrespiratory dust.The air curtain is a useful way to resolve the problem of dust-isolation at a fully mechanized working face.It has a practical background elsewhere with more extensive applications.
基金supported by the Special Foundation for Doctor Degree of the Ministry of Education(No.2006008001)the Construction Project of Beijing Municipal Education Committee (No.XK100080432)the Joint Development Project of Beijing.
文摘Gas-solid two-phase flow theory was used to predict dust distribution and movement at the working face of a mine.The software package FLUENT was used to numerically simulate dust motion and the results were compared to observed data.The simulation agrees with the data taken from an actual working face,which confirms the choice of mathematical model and numerical simulation method. Using the model we predict a set of conditions optimum for reducing dust concentrations at the mine working face.
