More than half of the energy sources in China are provided by combustion of coal from thermal power stations. By lowering the risk of excavating coal mines, we can decrease the price of the energy. This paper stresses the danger of coal mine gas explosions and constructs a gas explosion risk prediction system based on standard Hypo-Variance by using Brain Storms Optimization implemented with MATLAB simulation software. Hypo-Variance is the new concept built on the basis of Gauss Variance and can be used to make more precise risk assessments. By analyzing the multiple connections among gas density, temperature, humidity, pressure, air velocity, we can predict the trend of the gas event and propose the most safely timed schedule: operating three shifts in a day starting from a particular hour right after the gas peaking is over.

The study on developing the reasonable safety monitoring indexes plays a most importantly role in the health monitoring of high core rockfill dams. However, researches on this topic are relatively scarce both at home and abroad. In this paper, the characteristics and failure modes of seepage in high core rockfill dam are analyzed firstly. Then, a safety monitoring index based on seepage quantity, which reflects the overall seepage behavior, is developed, using the real-time monitoring data and its safety monitoring model. Moreover, another safety monitoring index based on seepage gradient, reflecting the local seepage behavior, is proposed, combining the spatial layout of osmometers and local failure mechanisms of core wall. Additionally, one more safety monitoring index based on permeability coefficient, which considers the overall and local seepage behaviors, is developed, on the basis of establishing the finite element analysis model and real-time seepage coefficient inversion analysis model of high core rockfill dam. A case study on these indexes of Nuozhadu high core rockfill dam is developed, which improves the reliability of seepage safety evaluation of the dam.

Degradation of dyes is an important environmental issue. In order to avoid the carcinogenic risks in anaerobic-aerobic biological process for wastewater containing azo dyes, a hemin based biomimetic oxidative degradation of azo dyes was developed. Acid orange 7 (AO7) was selected as the model for azo dye and the high efficient degradation was achieved in hemin/H2O2 system at pH 11.0. Degradation could be described by a pseudo-first-order kinetic model. The order of dependence on H2O2 concentration was significantly larger than that of hemin. Coexisting anions sulphate and chloride had little effect on the degradation, but reductive sulphite dramatically inhibited the degradation. The protic solvent 2-prophanol obviously promoted the degradation. Azo chromogenic group was destroyed quickly and some smaller intermediates formed. Active species oxoferryl porphyrin π-cation radical  + PFe IV =O generated from heterolytic cleavage of O-O in H2O2 catalyzed by hemin play the main roles in degradation and reaction pathways were proposed.

With the rapid economic development, China has sufficient foreign exchange reserves. Together with the appreciation in Chinese currency and other conditions, more and more Chinese enterprises invest overseas especially in the USA. Based on the statistics of the National Bureau of Statistics of the People's Republic of China, in 2012 and 2013, among the top 3 countries in which Chinese enterprises have invested, the USA ranked the second with US$ 4047.85 million and the third with US$ 3873.43 million respectively. Chinese enterprises' FDI in the USA has been mutually beneficial to both China and the USA. However, Chinese enterprises' FDI in the USA has encountered a variety of obstacles from the USA including American government's interfering with FDI by political methods, difficulty to enter into some industries, and America's protectionism. On the other hand, those Chinese enterprises also have some problems in their outward FDI in the USA such as unstable development trend of FDI, enterprises of small size with the privately-owned enterprises as the main body, and unfamiliarity with the related policies and laws. What countermeasures should Chinese enterprises adopt to deal with the obstacles or problems? This paper aims at analyzing the obstacles from the USA and the problems existing in those Chinese enterprises' FDI in the USA by means of SWOT method and puts forward some corresponding countermeasures for the Chinese enterprises to conduct their outward FDI in the USA more effectively. The conclusions can be used for reference by companies which plan to invest in the USA or other foreign countries.

We reviewed literature from 2014 to 2018 on foreign/second language learning supported by technologies. We aimed to select empirical studies that show effect of technologies on language learning. In this review study, we describe types of technologies, their potential usage for language learning, advantage and disadvantages, and we also give some examples to understand our findings better. Besides, we compare our results with those obtained from earlier review studies, e.g. we identified several new technologies used in studies between 2014 and 2018 but never used before. We also make several suggestions for future studies in this field. Our results can be useful for teaching and research communities that plan to design technology-enhanced foreign/second language learning and teaching.