Characteristics of mining gas channel expansion in the remote overlying strata and its control of gas flow

The technology of pressure relief gas drainage is one of the most effective and economic for preventing gas emissions in underground mines.Based on current understanding of strata breakage and fracture development in overlying strata,the current study divides the overlying strata into the following three longitudinal zones in terms of the state of gas flow:a turbulent channel zone,a transitional circulation channel zone and a seepage channel zone.According to the key strata discrimination theory of controlling the overlying strata,the calculation method establishes that the step-type expansion of the mining gas channel corresponds to the advancing distance of working face,and this research also confrms the expanding rule that the mining gas channel in overlying strata follows the advancing distance of mining working face.Based on the geological conditions of Xinjing Coal Mine of Yangquan,this paper researches the expanding rule of mining gas channel as well as the control action of the channel acting on the pressure relief flow under the condition of the remote protective layer,and got the distance using inversion that the step-type expanding of mining gas channel is corresponding to the advancing distance of working face,which verifes the accuracy and feasibility of theoretical calculation method proposed in this study.The research provides the theoretical basis for choosing the technology of pressure relief gas drainage and designing the parameters of construction.

Research on Meteorological Administrative Power and Its Expansion and Control

At first, we briefly introduced fuzzy sets and related concepts of meteorology and meteorological administrative power to build the basic theoretical framework of the meteorological administrative power. Then, the attributes of meteorological administrative power were analyzed, espe- cially implementation and functions, and it was divided into five types like supervisory power for meteorological forecast. Finally, meteorological ad- ministrative power＇s expansion and control methods were discussed. It acts as the research foundation in practice to improve the meteorological ad- ministrative law enforcement and achieve meteorological public interest better.

Risk Control Amid Rapid Expansion

China’s flourishing hotel industry not only presents endless business opportunities but also poses unprecedented risks for international hotel management companies. In a recent article, Gary Tillyer, Vice President of the Argyle Hotel Group (Australia) in China, put forward a series of risk control guidelines. Excerpts follow:

Landscape changes have greater effects than climate changes on six insect pests in China

In recent years, global changes are the major causes of frequent, widespread outbreaks of pests in mosaic landscapes, which have received substantial attention worldwide. We collected data on global changes(landscape and climate) and economic damage caused by six main insect pests during 1951–2010 in China. Landscape changes had significant effects on all six insect pests. Pest damage increased significantly with increasing arable land area in agricultural landscapes. However, climate changes had no effect on damage caused by pests, except for the rice leaf roller(Cnaphalocrocis medinalis Guenee) and armyworm(Mythimna separate(Walker)), which caused less damage to crops with increasing mean temperature. Our results indicate that there is slight evidence of possible offset effects of climate changes on the increasing damage from these two agricultural pests. Landscape changes have caused serious outbreaks of several species, which suggests the possibility of the use of landscape design for the control of pest populations through habitat rearrangement. Landscape manipulation may be used as a green method to achieve sustainable pest management with minimal use of insecticides and herbicides.

扩张还是自守——儒家战略审慎主义及其对立面

在是否向外采取扩张性政策的问题上,古代"中原王朝"的决策层有时会存在分歧与论战。从战略文化角度来看,反对扩张性政策的一方坚持儒家战略审慎主义,它由基本理念和现实政策逻辑两部分构成;支持扩张性政策的一方则属于儒家战略审慎主义的对立面,它主要由体系结构压力催生出来的三种战略逻辑构成,即地缘安全关联主义、大国威望主义与战略机会主义。尽管在西汉、唐朝和清朝经略西域的案例中,儒家战略审慎主义的对立面在12场论战中胜出的次数更多,但儒家战略审慎主义才是古代"中原王朝"的主导性和常态性战略文化,其对立面只是次要性和应激性战略文化。二者之间的分歧针对的是具体问题,并非观念上的系统性对立。儒家战略审慎主义的对立面虽然支持扩张性政策,但这种支持是有条件和有节制的,在性质上仍属于防御性,这与近代西方列强的扩张主义有根本不同。儒家战略审慎主义有审慎性、民本性、道德性和理想性四个积极特性,也存在主观性和狭隘性等消极问题。