Being a unconventional resource, shale gas is usually generated and preserved in-situ, and its ultra-low permeability results in huge difficulty for commercial development. A typical shale gas production profile would start with high level initial production, followed by a sharp decline and a long-term of low level production. The global shale gas resource volume, the development technology and the significance of shale gas development are summarized, and the development status of shale gas industry in China is introduced as well. The shale gas geological resource of China is estimated as 134.42×10¹² m³, and the technically recoverable resource is 25.08×10¹² m³. Engineering experiences have proved that "horizontal well+volume fracturing+factory operation" is a successful and effective mode of shale gas development. China has so far preliminarily developed three marine shale gas reservoirs, i.e.,Changning-Weiyuan, Zhaotong and Fuling, and the total productivity is 97×10¹² m³/a. The efficient development of shale gas will help China relieve the imbalance between energy supply and demand, adjust the energy consumption structure, strengthen the influence on international pricing power of natural gas, and boost regional economic development.

Through a comparison between China and US in shale gas resource, geology, development technologies and other aspects, it is shown that the shale gas development in China is characterized by favorable resource bases and high starting point of both exploration and development technologies, in addition to the positive policy support from government. On the other hand, much attention has been paid to environmental protection from the government and enterprises as well. However, there are still some negative factors, such as relatively poor geological and surface conditions, immature technical series and assistant technologies. Therefore, for the actual situation, some key technical issues must be resolved to overcome the adverse aspects caused by these actual factors and realize commercial shale gas development in China. These technical issues include core-zone optimization, development and optimization of engineering technology series which are applicable to specific geological and surface conditions, development of "gas-factory" operation mode, etc.

This paper provides an overview of the key mechanical problems of hydraulic fracturing process including rock deformation due to the fluid pressure on crack surfaces, crack initiation and propagation, fluid flow within cracks and their couplings. The fundamentals of the numerical methods for hydraulic fracturing are reviewed with their progress and development trend, for example, finite element method, discrete element method, boundary element method and other related numerical methods. These methods are analyzed and compared in terms of advantages and applicability.

Horizontal drilling is one of the core technologies in US shale gas large scale exploration. Oil based mud (OBM) was applied successfully at the beginning, however, due to its environmental reason and high cost, water based mud (WBM) was developed and applied. Three typical WBM cases for shale gas are introduced in this article. In the Haynesville area, a condition close to downhole environment is used to evaluate drilling fluid anti-contamination properties, including 1.38 MPa CO₂, 12% solid and hot rolling at 204℃ for 48 h. Rheological properties are tested by stimulating well temperature and pressure variations during the processes of fluid flowing in, staying static in bottom hole, and flowing out. In Fayetteville and Barnett areas, the interaction mechanism between WBM and shale is investigated to form drilling fluid formulation using SEM so as to analyze the morphology of soaked rocks. In Haynesville, with CO₂ contamination and 204℃ temperature, the ROP increases by 8.5%, compared with adjacent OBM well. In Fayetteville and Barnett, the sliding drilling speeds are 9.2-15.4 m/h and 7.4-24.6 m/h, respectively and the rotating speed is 30.8-77.0 m/h when using nano-silica-alcohol WBM. The development and application of US shale gas horizontal well WBM are worth learning by China.

At present, China has commercially exploited shale gas in a large-scale. However, the shale gas development may bring risks for water resources and environments. By surveying water consumption, sampling and analyzing flowbacks from shale gas drill sites in Sichuan and Chongqing, it is shown that the total water consumption is huge for the shale gas development, i.e., each well consumes about 32000 m³ of water. On the other hand, potential risks of water pollution come from several sections during shale gas development:firstly, fracturing and drilling flowbacks produce water having high salinity, complex components and a variety of heavy metals; secondly, a huge amount of waste fluids and oil-based mud cuttings are produced in the drilling process; thirdly, drilling circulation loss often happens in shale gas development areas where caves, cracks and underground rivers largely exist; and fourthly, constructions of the ground engineering. Besides, storage pools are apt to spill and leak by heavy rain or other factors. Therefore, when shale gas is extracted from Sichuan and Chongqing, constructions, allocation of water resources, and developing treatment technology of flowbacks must be meticulous. It is important to prevent water resources from being consumed excessively and water environment from being polluted in the developing shale gas.

The large-scale development of renewable energy generation such as wind energy and solar energy has brought enormous pressure to the safety and stability of the power system. Power system is in urgent need to configure large capacity energy storage systems, compensate power change, and adapt to the large-scale development of new energy sources. More importantly, the demand for load adjustment has recently been very urgent because of low power load rate and fast power fluctuation. The best solution to the problem of safety and stability of power grid, caused by large-scale development of new energy such as wind power, is to install pumped storage station in an appropriate scale. This paper analyzes the pumped storage technology principle and characteristics, expounds the new trend of pumped storage technology development:the construction technology of extra high water head and high capacity; manufacturing technology of large capacity pump turbine; rotor AC excitation technology of variable speed pumped storage units and full size converter technology; the construction and operation technology of pumped storage station for coastal and alpine regions. This paper focuses on the variable speed pumped storage technology, presents the overall structure of the double feed mode and full size converter mode, and puts forward the control strategy in different modes. The composition, technical challenges and solutions of the new special pumped storage power station are also presented in this paper.

SMES stores the magnetic energy in the superconducting coil. It has the advantages of fast response, high conversion efficiency, fast power compensation, etc. Therefore, SMES is an ideal device for improving the quality and reliability of the electrical system. This paper presents an overview of the SMES technology, including its working principle, current research status, major advantages and disadvantages. The potential application prospects of SMES are also presented.

Currently, compressed air energy storage (CAES) is a topic of general interest in the field of large-scale power storage technology research and development, because it has a broad application prospect in both grid-connection of new energy power generation and peak-load regulation of power grid. The research and development of air compressor is reviewed in this paper. Due to the fact that it is difficult for adiabatic process based equipment to improve working efficiency, screw air compressor has been proposed to reduce gas temperature by compression of mixed oil and gas, further lowering down the energy consumption. For the different evolution periods of CAES, including traditional gas-heating compression, non-gas-heating adiabatic compression and isothermal compression, different principles and variable efficiency are analyzed and compared. Realization methods and the latest development of isothermal CAES are introduced in detail. Finally, combined with the current situation, the future development direction of CAES technology is prospected.

Rechargeable lithium-ion batteries (LIBs), due to their high energy density and design flexibility, are the most prevailing and promising electrochemical energy storage and conversion devices, and are being widely used in portable electronics and electric vehicles. However, with their wide range applications, an urgent requirement is raised for the further improvement of their energy density. This paper presents an overview of recent advances in understanding the mechanical behavior of high capacity anode materials, i.e., silicon and germanium, in their charging/discharging cycling. Particular emphasis is placed on the state-of-the-art experimental and numerical studies of the deformation and failure of anode materials caused by the electrochemo-mechanical coupling. In addition, possible extension of current techniques to the research of other energy systems is discussed.

Since its central wavelength is exactly equal to that of alkali D₁ line without frequency stabilization, alkali laser is of great potential in the spin-exchange relaxation free (SERF) atomic magnetometer. In this paper, the research developments of SERF atomic magnetometers' pumping source and alkali lasers are presented. The qualifications of a good pumping source for SERF atomic magnetometers are analyzed. And the prospects and the challenges for alkali lasers' application to the pumping of SERF atomic magnetometer are also discussed.

Due to the scaling challenge faced by silicon transistors, carbon nanotube (CNTs), being one-dimensional quantum material, becomes a candidate for future transistors. Carbon nanotube field effect transistors (CNTFETs) can be realized in several geometrical configurations. This paper begins with a survey of typical CNTFET device geometries, the associated basic operating principles, and the unique properties. Then, it focuses on the recent development of several common CNTFETs, and describes in detail a series of technical innovations and performance improvements in terms of. structural and operating principles. Finally, some key problems about CNTFETs to be solved in future are summarized.

Parallel robots are usually used in occasions requiring high reliability, such as surgical operation, space station remote control and high-speed motion mechanism. Methodologies for parallel robot diagnosis are studied using fault tree analysis in this paper. A summary of mechanical failure levels, modes, effects and causes of parallel manipulators is tabulated to establish the fault tree analysis for parallel robots. Qualitative and quantitative results are presented with probability levels,and the general rules of highly reliable parallel robots for application are derived.

The Mediterranean is one of the newly emerging places of petroleum exploration. After 2009, there were a series of discoveries in the Eastern Mediterranean, indicating it is an enriched hydrocarbon area. Up to now, 19 basins were found with about total 4.47 billion tons of oil equivalent. And about 12.8 billions tons of oil equivalent resources remain to be discovered. The petroleum and gas resources are primarily distributed in the Eastern Mediterranean, followed by the Central Mediterranean. Most reserves are located in offshore, with water depth less than 300 m, followed by those in deeper water, with water depth more than 500 m. There are many big fields and gigantic fields in this area, mostly located in the Eastern Mediterranean and are not in enhanced production. There is enormous potential for exploration in the Mediterranean with an obvious difference between the Eastern and Western Mediterranean. The main potential is in the Western Mediterranean. And the Central Mediterranean potential area is primarily in new layers. The Eastern Mediterranean potential areas are both in new layers and in deep layers.

In order to take the advantages of new technology such as the Internet of Things and the indoor location, and make full use of the characteristics of library, a mobile library recommendation system is designed and developed. System data is collected by using the NFC in the Internet of Things. Then, the item-based collaborative filtering recommendation and the hot recommendation, which respectively use Mahout and Redis, are mixed and weighted to get a list of recommended books. The position of the reader is obtained by the position fingerprint location method. Accordingly, a mixed recommendation result is presented to the reader. At the same time reader's feedback is designed to optimize the recommendation, therefore, the recommendation system can better serve the reader.

Since 1980s, in order to further accelerate the process of technology transfer, the U.S. government has formulated and implemented a series of laws and regulations, and established a relatively perfect policy system. On the other hand, many policy measures have been implemented, such as, providing adequate funding for transformation project, paying more attention to information extension services of achievements, supporting the cooperation between enterprises and scientific research institutions, encouraging researchers to actively participate in technology transfer and technological innovation, just to name a few. The successful experiences and practices are worth referencing by China in respects of improving the laws and policy system in terms of promotion of technology transfer and technological innovation.