This paper uses irregular feedback linearization to stabilize nonholonomic chained systems. A discontinuous nonlinear transformation is constructed to change nonholonomic chained systems into linear systems,so that it possible to design feedback control laws using theory of linear systems. Then, a convenient invariant set and a switching rule are explicitly constructed for the high-dimension nonholonomic chained systems. The obtained discontinuous control laws can guarantee convergence of the close-loop system with an exponential rate and bounded inputs. Finally, simulation is provided to justify the effectiveness of the approach.

The concentrations of PM₁₀ within the 70 m height range at the South Second Ring of Xi'an were monitored for 4 days and nights in May 2013 by a microcomputer laser dust monitor. The results show that PM₁₀ concentration varied in 5 phases of the day.The first phase was at am 8:00-10:00, with an average concentration of 0.056 mg/m³. The second was at 12:00-14:00, with an average concentration of 0.075 mg/m³. The third was at pm 16:00-18:00, with an average concentration of 0.058 mg/m³. The fourth was at 20:00-22:00, with an average concentration of 0.070 mg/m³. The fifth one was in the night of 0:00-6:00, with an average concentration of 0.038 mg/m³. High resolution vertical observations indicate that Xian vertical variation of PM₁₀ concentrations can be divided into three types in May. The first type decreases as altitude increases PM₁₀ concentration increases was middle, the average increase rate for 0.048 μg/m. The second type as the altitude increases PM₁₀ concentration was the highest increase rate for 0.065 μg/m and volatile changes significantly. The third type as the height increases PM₁₀ concentration was the lowest and the increase rate for 0.013 μg/m. At the height of 70 m the mass concentration of PM₁₀ was the highest, the mean value being 0.56 mg/m³; the concentration at 1m height was the lowest, the average concentration being 0.048 mg/m³. In the range of 4-46 m height, the PM₁₀ mass concentration was the second lowest, with an average concentration of 0.051 mg/m³. In the scope of 49-67 m, the PM₁₀ mass concentration was the second highest, with an average concentration of 0.052 mg/m³, which presented a remarkable increasing trend. During the observation period, the mass PM₁₀ concentration and the temperature had a marked positive correlation at the height of 4 m (Correlation formula is y=240.73x +12.305). The mass PM₁₀ concentration and the humidity had a marked negative correlation at the heights of 4, 7, and 10 m (Correlation formula is y=-6.0668x+0.821).

The effects of the reaction time, the reaction temperature, the dosages of catalyst, phenol, and tetralin on the liquefaction ratio of the Salix psammophila with phenol-tetralin as the hydrogen-donor solvents are investigated by orthogonal and single factor tests. The optimal conditions are found as follows: the reaction temperature is 120℃, the time duration is 2 h, the phenol dosage is 15 g, the catalyst (98%H₂SO₄) dosage is 1 mL, the tetralin dosage is 5 mL. The liquefaction efficiency is 97.51% under these conditions. The order of importance of these factors is: Reaction temperature > reaction time > dosage of catalyst > dosage of tetralin > dosage of phenol. The infrared spectrograms of the liquid products at different reaction times in the liquefaction see new peaks before 30 min and have similar spectrogram characterizations after 30 min. The FTIR of the solid residue indicates that the hemi-cellulose and the lignose are degraded firstly. The fractures of the spatial network structures of the lignin formed by the ether bonds precede those of the carbon-carbon bonds among aromatic nucleus, and the pyranose rings and the hydroxyl bonding groups are contained in the final solid residue of liquefaction. The thermogravimetric analysis of the solid residue suggests that the organic matter in the product is gradually reduced along with the liquefaction. And the pyrolysis reaction shows obvious phases and is divided into two stages.

The porous silica optical antireflective coating is prepared by the sol-gel method with the tetraethoxylsilane as the precursor and the ammonia as the catalyst via a dip-coating process. The environment stability of the antireflective coating could be greatly improved by post-grafting 1H, 1H, 2H, 2H-perfluorodecyltriethoxysilane (FAS-17) and hexamethyldisilazane (HMDS). The properties of the coating are characterized by the UV-VIS spectrometer, the FTIR spectrophotometer, the atomic-force microscopy, the contact angle measurement and the anti-pollution test. The results indicate that for the modified coating, the peak transmittance is up to 99.82%, the surface roughness is only 3.9 nm, and, the contact angle with water is 125°. Especially, the decrease of the transmittance when being tested with water and polydimethylsiloxane pollution in vacuum for two months is as small as 0.03%, suggesting that the coating has an excellent environment stability.

Activated carbons are prepared from the external wall insulation board residual material by the alkali activation method. The performance of the activated carbon is characterized by the FT-IR spectroscopy, the X-ray diffraction, the BET specific surface area, the pore size distribution and the iodine adsorption value. The external wall insulation board is heated from the room temperature to 800℃ at the rate of 10℃/min under the atmosphere of nitrogen and maintains for 30 min. Then it cools to the ambient temperature to obtain charcoal powder. At the ratio of 4∶1(alkali/carbon), the charcoal powder is impregnated for 8 h with 0.1 g/mL KOH solution and is transferred to the activation furnace after being heated to remove water. The charcoal powder is heated from the room temperature to 800℃ at the rate of 10℃/min under the atmosphere of nitrogen, is activated for 60 min, naturally cools down to the room temperature, is washed with 5% hydrochloric acid and water to neutralize, and then is dried to a state of constant weight at 120℃. In the process, the index parameters of the activated carbon are found to be as follows: The iodine value is 2300.27 mg/g, the specific surface area is 1293.45 m²g, the average pore size is 2.4 nm, which is mainly composed of micro pores and small middle pores.

Jeopardized by poor reservoir properties, gas wells in low permeability reservoirs with bottom water should be fractured in order to acquire industrial capacities. Therefore, a modified equation for predicting well's water breakthrough time is studied for effectively developing low permeability gas reservoirs with bottom water. Based on the characteristics of seepage flow in fractured wells, the seepage field is divided into two parts, the perforation interval and its lower section. With the aid of steady state seepage theory, productivity equations for all fields are derived respectively. Eventually, a modified prediction equation is established by means of utilizing the motion equation of water cone apex. Case study shows that fracturing will postpone the process of water breakthrough and the time calculated by this article has less error as compared with the value gained by practical production data. The analysis on sensitive factors reveals that each parameter has its optimal value. With the increase of perforation degree, water breakthrough time will increase at first and then decrease. And the larger the fracture half-length and conductivity are, the longer the water breakthrough time will be. However, the increasing rates tend to be reduced gradually.

Conventional continuous multiple medium theories are not suitable for describing the fractured-cavernous carbonate reservoir with big-size fractures and caves. An interpretation model for well test of naturally fractured vuggy reservoir has been developed with consideration of wells drilled outside a big cavity. The model equations are solved with the finite-element method. The analysis of the affecting factors of dynamic pressure at well bottom indicates that the pressure derivative curve of the late stage will go down and form a concave because of the high permeability of the cave. The scale and permeability of the cave mainly affect the amplitude of the pressure derivative reduction. The predicted model has a good agreement with the field test. This can provide a theoretical basis and guidance for well test interpretation of carbonate reservoir.

In order to apply the technology of the microbial enhanced oil recovery in the Longhupao oilfield of Daqing, a series of experiments are conducted in our laboratory. Two strains of microbes are considered in the experiment. The endogenous microbe DH8 is screened from the Longhupao oilfield formation water, identified as the Geobacillusstearothermophilus; the inoculating microbe SL21 is selected from the strain library, identified as the Bacillus licheniformis. Their emulsification property, degradation ability and oil displacement efficiency are studied. It is shown that the specific capillary numbers of the DH8 and the SL21 are 0.0239 s/m and 0.0332 s/m, respectively; the viscosity reductions of the oil are 19.02% and 26.08% after the applications of the DH8 and the SL21. The linear Alkanes in the C₁₃~C₂₇ are mainly degraded by the DH8, and the linear Alkanes in the C₁₉~C₃₇ are mainly degraded by the SL21, but the short-chain n-alkanes before the C₁₃ are both increased by 5.33% and 11.00% after the applications of the fDH8 and SL21. The physical flooding simulation experiments show that the oil displacement efficiency of the SL21 and the DH8 are 7.11% and 5.5%, respectively. Therefore, the oil displacment performance of the SL21 is better than that of the DH8.

For calculation of density of drilling fluid in down-hole HTHP environment, a simplified calculation method is presented, which combines the composite model and empirical model methods with the actual on-site drilling operation. The method solves the liquid density calculation in drilling fluid composition by considering the liquid water and the liquid oil density changing with temperature and pressure as well as taking into account the components of drilling fluids. Experiment verification with a certain typical water-based drilling fluid and oil-based drilling fluid shows that the method can not only meet the calculation precision demand of engineering but also provide an easy calculation means of high operability.

Due to the limited well test data, it is difficult to obtain effective information about deliverability in some wells. In this paper, the calibration factor of deliverability is introduced and the calculation methods of the influencing factors are studied, to establish a deliverability forecasting method. The geophysical logging static information is first calibrated by the dynamic data of the well test. Then the deliverability of the whole field is forecasted by the calibrated static data. The seismic data, the geophysical logging data at the beginning of exploration and production, and the well test dynamic data of few important wells are made the best use in this method. This method is applied in some wells in the M gas field. The forcasting deliverability results agree well with the actual deliverability. The calculation precision of the new method is high enough to meet the demand of the project design.

In order to understand the flow characteristics of high concentration slurry, a mathematical model of filling slurry pipeline transportation is established by combining the fluid dynamics theory and the characteristics of the filling slurry under the assumption including fluid particle, uniformity and continuity in the case of no segregation. According to the result of a certain mine industrial test, a numerical simulation on the resistance of slurry pipeline transportation was made by the Fluent software. Through the comparison of simulation and measured results, the error was found to be around 5%. At the same time, the relationship between the slurry flow rate and loss of resistance along the way was obtained. The drift velocity range of slurry pipeline was calculated to be around 1.82~2.23 m/s by the above relationship and mathematical model. The numerical simulation results could provide a basis for the filling system piping design. Besides, they could be used to guide the actual mine production.

The Pinobanksin-3-acetate (PB3A) is a natural flavonoid commonly present in propolis, honey, and many plants. The purpose of this study is to evaluate the anticancer activity of the PB3A on the human colon cancer in vitro. The effect of different concentrations of PB3A, 5-fluorouracil (5-FU) and a combination of PB3A and 5-FU for different durations on the proliferation of the cell line HCT-116 is analyzed by the MTT assay. The morphological changes of HCT-116 cells are observed by the inverted photo microscopy after treatment with different concentrations of PB3A for 24 h. The 24 h apoptotic rates of the HCT-116 cells induced with PB3A and 5-FU are determined by the FCM with Annexin V-FITC/PI double labeling. The results show that the PB3A has a significant inhibitory effect on the HCT-116 cell proliferation and in a time-and dose-dependent manner, and an additive or synergistic effect is shown with the common chemotherapy drug 5-FU. The PB3A could induce the typical changes of cell morphology in a dose-dependent manner. The FCM analysis shows that the PB3A could significantly increase the apoptosis rate in a dosedependent manner. The findings in this study suggest that the PB3A can play a potential anticancer role for the colon cancer in vitro, and it could induce the apoptosis.

To aim at the ultra wideband fuze antenna bandwidth and the volume factor, modeling and simulation of the UWB antenna are studied with computer simulation technology. The UWB fuze antenna voltage standing-wave ratio and antenna gain are analyzed in the frequency domain, and the UWB antenna radiation characteristics of signals and antenna pattern are analyzed in the time domain. In comparison the time domain analysis method is more suitable for ultra wideband antenna. It is shown that for ultra wideband fuze antenna, priority should be given to the time domain method, with the frequency domain method as a supplement, in order to get an ideal simulation result.

The web related software development shows a trend of more frequent changes in user demands and a shorter development period. In order to improve the efficiency and the accuracy of software test, a quick response high quality testing platform has been successfully built. According to the layered software architecture and based on the continuous integration platform, Ant, Selenium 2.0, TestNG, and Sonar are integrated to provide a solution to solve continuous construction, test and code quality monitor of the whole process of testing automation of a software system. It is shown that the solution can greatly improve software test efficiency with a high reliability.

Fairness is an essential ingredient in human society. Numerous studies have confirmed that people have fairness preference. With regard to the neural basis of fairness, researchers are focusing on the issue of neural mechanism that underlies fair behavior using neuroimaging techniques, and suggest a possibility to transfer the findings in the neural basis of fairness into clinical applications. In this paper, we first introduce a game theory-based paradigm for investigating fairness—the ultimatum game, and then review neuroimaging studies based on this game. In addition, we address the factors that may influence fairness and their neural mechanisms, namely, stake size, gain-loss contexts, framing effect, group opinion, social status, and emotion. We also summarize the studies that use the ultimatum game to investigate the clinical population, such as major depressive disorder, psychopathy, and antisocial adolescents. Meanwhile, we propose the followings: the neural mechanism of fairness should be examined from the perspective of brain networks, the influence of specific social contexts on fair behavior should be considered, the application of game theory paradigms in neuropsychiatric disorders should be strengthened, and the models of neural computation underlying fairness should be explored more deeply in future studies. Finally, we briefly introduce some Chinese researchers that are representative in this area.

This paper identifies ten kinds of environmental pollutants with antiestrogen effects, focusing on their antagonist effects on the E₂ levels, the E₂ function and the female characters. Furthermore, the mechanism of antiestrogen effects in the synthesis, the transportation, the receptor binding and the metabolism of E₂ is discussed. Finally, based on the above analyses, the future researches of the antiestrogen effects and the underlying mechanism of environmental pollutants are suggested.

Tight oil resources are abundant in China, but at present the domestic technology for tight oil development remains at the exploration stage. The US has the most mature technologies for tight oil development all over the world, which may provide significant reference for tight oil development in China. The analysis of tight oil development process in the US indicates that horizontal well technology and hydraulic fracturing technology are the key to successful development of tight oil. The matching techniques and tools are the most important components of the technology, including horizontal well patterns, rotary steering tools, walking drilling machine, and staged/segmented stimulation techniques and tools. This paper summarizes the drilling techniques, matching tools, drilling equipment, fracturing techniques, staging completion tools and fracturing operation parameters in US tight oil development, based on understanding of the key technologies concerning tight oil drilling and hydraulic fracturing in the US. Comparison of tight oil development in China and the US shows that the key to efficient tight oil development in China is international cooperation and independent research and development of relevant technologies.

The temporal trend, regional distribution, subject type, author, organization and key works of researches are analyzed from the core database of Web of Science^TM based on the bibliometrics method. The obtained results indicate that the study of the Three Gorges Reservoir has shown a sharp increasing tendency since the secondary period impoundment of the Three Gorges Reservoir in 2006. Most of research papers are from China and the major popular journals are Geomorphology and so on. Among the research institutions, Chinese Academy of Sciences, Beijing Normal University, East China Normal University have strong influences in this field. The major focusing issues include the effect of Three Gorges Reservoir on ecological environment, geological disaster, immigration in the middle and lower Yangtze River and reservoir region, among which ecological environment problem has attracted the most attention. Based on these analysis, development and application of models in this region, non-point source pollution, greenhouse gas emissions and their impact on climate change might become hot issues in the future.