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
Introduction: Complex post-traumatic facial disfigurements are caused by civilian or ballistic trauma. Their repercussions are functional, aesthetic and psychological. The initial emergency or secondary management of ...Introduction: Complex post-traumatic facial disfigurements are caused by civilian or ballistic trauma. Their repercussions are functional, aesthetic and psychological. The initial emergency or secondary management of facial damage is difficult. The objective is to report, through the clinical observation of three patients, the results of the management of complex facial dislocations in a context of limited technical resources. Patients and methods: Three complex post-traumatic facial dislocations were managed between May 2006 and June 2017. Results: Primary treatment and secondary repair were established on a case-by-case basis. Local autoplasty was the indication of choice. Multidisciplinary management resulted in satisfactory functional and cosmetic outcomes. Two of the patients were lost to follow-up before the end of treatment. Discussion: The complete management of facial dislocations remains difficult and complex, in an extreme exercise situation. In an emergency, the priority is to save the life of the injured person. Several factors are involved in the therapeutic decision: the choice of the maxillofacial reconstruction technique, the availability of the technical platform, the financial capacity and the psychological state of the patient and his entourage. Sequential and multidisciplinary treatment gives satisfactory results in terms of morphology, function and aesthetics, despite the limited technical resources available. Psychological support is an essential complement for successful socio-professional and family reintegration.展开更多
Interface imperfection can significantly affect the mechanical properties and failure mechanisms as well as the strength and toughness of nanocomposites. The elastic behavior of a screw dislocation in nanoscale coatin...Interface imperfection can significantly affect the mechanical properties and failure mechanisms as well as the strength and toughness of nanocomposites. The elastic behavior of a screw dislocation in nanoscale coating with imperfect interface is studied in the three-phase composite cylinder model. The interface between inner nanoin- homogeneity and intermediate coating is assumed as perfectly bonded. The bonding between intermediate coating and outer matrix is considered to be imperfect with the assumption that interface imperfection is uniform, and a linear spring model is adopted to describe the weakness of imperfect interface. The explicit expression for image force acting on dislocation is obtained by means of a complex variable method. The analytic results indicate that inner interface effect and outer interface imperfection, simultaneously taken into account, would influence greatly image force, equilibrium position and stability of dislocation, and various critical parameters that would change dislocation stability. The weaker interface is a very strong trap for glide dislocation and, thus, a more effective barrier for slip transmission.展开更多
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Introduction: Complex post-traumatic facial disfigurements are caused by civilian or ballistic trauma. Their repercussions are functional, aesthetic and psychological. The initial emergency or secondary management of facial damage is difficult. The objective is to report, through the clinical observation of three patients, the results of the management of complex facial dislocations in a context of limited technical resources. Patients and methods: Three complex post-traumatic facial dislocations were managed between May 2006 and June 2017. Results: Primary treatment and secondary repair were established on a case-by-case basis. Local autoplasty was the indication of choice. Multidisciplinary management resulted in satisfactory functional and cosmetic outcomes. Two of the patients were lost to follow-up before the end of treatment. Discussion: The complete management of facial dislocations remains difficult and complex, in an extreme exercise situation. In an emergency, the priority is to save the life of the injured person. Several factors are involved in the therapeutic decision: the choice of the maxillofacial reconstruction technique, the availability of the technical platform, the financial capacity and the psychological state of the patient and his entourage. Sequential and multidisciplinary treatment gives satisfactory results in terms of morphology, function and aesthetics, despite the limited technical resources available. Psychological support is an essential complement for successful socio-professional and family reintegration.
基金supported by the National Natural Science Foundation of China(11172094 and 11172095)the NCET-11-0122 and Hunan Provincial Natural Science Foundation for Creative Research Groups of China(12JJ7001)
文摘Interface imperfection can significantly affect the mechanical properties and failure mechanisms as well as the strength and toughness of nanocomposites. The elastic behavior of a screw dislocation in nanoscale coating with imperfect interface is studied in the three-phase composite cylinder model. The interface between inner nanoin- homogeneity and intermediate coating is assumed as perfectly bonded. The bonding between intermediate coating and outer matrix is considered to be imperfect with the assumption that interface imperfection is uniform, and a linear spring model is adopted to describe the weakness of imperfect interface. The explicit expression for image force acting on dislocation is obtained by means of a complex variable method. The analytic results indicate that inner interface effect and outer interface imperfection, simultaneously taken into account, would influence greatly image force, equilibrium position and stability of dislocation, and various critical parameters that would change dislocation stability. The weaker interface is a very strong trap for glide dislocation and, thus, a more effective barrier for slip transmission.
