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The spray characteristics of a gas-centered shear coaxial injector under different conditions and recess ratios (RR) were studied through experiments and numerical simulations. The numerical study was carried out based on the coupled level set and volume-of-fluid (CLSVOF) method and the adaptive mesh refinement (AMR) method. The results indicated that without recess, the spray angle first stayed almost constant and then dropped linearly with an increase in the gas mass flow rate (m˙g) when holding the liquid mass flow rate (m˙l) constant. In contrast, with recess, the spray angle was found to increase with m˙g, which could be attributed to the secondary expansion of the central gas flow. Under specific conditions, self-pulsation occurred and was accompanied by a loud scream. The frequency of the self-pulsation increased with both m˙g and m˙l. Moreover, the self-pulsation frequency decreased with RR. Meanwhile, the mechanism of self-pulsation was initially explored through numerical simulation. It was concluded that self-pulsation was caused by the surface tension and the pressure difference between the inside and outside of the liquid sheet, together with the central airflow impact extrusion.

The dynamic atomization characteristics of gas center coaxial centrifugal nozzle under the condition of pressure oscillation in the supply system were studied by applying external excitation through the flow pulsator. Obtaining spray image by high-speed photography while using hydro-mechanical pulsator to get generate of supply system. The results show that the spray width changes periodically with low-frequency pressure oscillation. For self-pulsation sprays, it is challenging to maintain a “Christmas tree” shape with low-frequency oscillation. Pressure oscillation can effectively suppress spray self-pulsation. However, the pressure oscillation amplitude may be much larger than that of the self-pulsation itself. Therefore, the premise of applying this method is that the applied external excitation cannot stimulate or amplify the combustion instability. The gas post-pressure drop determines the amplitude and frequency of the self-pulsation, while the excitation frequency will slightly affect the amplitude and frequency of the self-pulsation.

The Denglouku Formation in the paleo-central uplift of the Songliao Basin is a large thick clastic deposit that has important oil and gas exploration potential. However, the natural gas in the Denglouku Formation has not yet formed to the necessary scale. The paleo-sedimentary environment plays an important role in controlling the development of source rocks and the physical properties, development, and distribution of reservoirs. Therefore, studying the paleo-sedimentary environment has important guiding significance for the formation and accumulation of oil and gas. In addition, studying the paleo-sedimentary environment of the Denglouku Formation can effectively reconstruct the terrestrial climate change in the Cretaceous and provide basic terrestrial geological data for studying the global Cretaceous paleoclimate, paleoenvironmental changes, and greenhouse climate. This paper uses clastic rock geochemistry, especially V/Cr, V/(V + Ni), Sr/Cu, SiO2/Al2O3, and Sr/Ba ratios and DF1, DF2, as well as other characteristic values and discriminations, to confirm that the depositional environment gradually changed from an oxygen-poor or reducing environment in the center to an oxygen-rich environment on the north and south sides; the climate in the north was drier and hotter than that in the south, and the humid climate in the south led to strong chemical weathering. There was a tendency to gradually evolve from a marine to transitional to freshwater environment from north to south. The source area was an active continental margin and a continental arc.

This study investigated the effects of backpressure and operating conditions on the self-pulsation characteristics of a liquid-centred swirl coaxial (LCSC) injector. To this end, a three-dimensional numerical simulation via octree adaptive mesh refinement as well as coupled level-set and volume of fluid method were employed. Self-pulsation is suppressed by backpressure for a constant gas–liquid momentum flux ratio (MFR). When backpressure is constant, the strength of self-pulsation varies with the mass flow rate of the gas ( m ˙ g ), which is constant with experimental data due to the variation in the flow patterns in the recess chambers. The self-pulsation frequency increases with backpressure and m ˙ g . The trends of the spray angle and intensity of self-pulsation are consistent. As backpressure increases, the radial distribution of the mass flow rate of the liquid changes from a double- to single-peak. The central mass flow rate increases with backpressure and m ˙ g , which also affect the pressure oscillations inside and outside the liquid film in the injector. We proposed a self-pulsation mechanism, in which self-pulsation is closely related to the dominant surface wave and Kelvin–Helmholtz (K–H) instability. Self-pulsation under the critical mixing flow pattern is stronger than that under inner or outer mixing flow patterns. Under the critical mixing flow pattern, the K–H vortex is relatively strong, and the spray oscillation is not restricted by the wall of the recess chamber.

The volcanic gas reservoir in the Songliao Basin is a complex reservoir which has the characteristics of deep burial, complex structure, faults and fractures, wide distribution and no obvious regularity. All of these make seismic imaging and interpretation difficult. The seismic modeling of the volcanic gas reservoirs at the Xujiaweizi Depression of the Songliao Basin, which has dense well network-3D seismic survey, is carried out; the seismic wave field forward modeling and migration imaging are studied by the lithofacies,lithologies and other formation parameters; which factors affected volcanic reflection characteristic; then, the seismic response characteristics of the volcanic gas reservoirs is definituded. Seismic interpretation and reservoir prediction results is better guided and corrected.

Combination forecasting takes all characters of each single forecasting method into consideration, and combines them to form a composite, which increases forecasting accuracy. The existing researches on combination forecasting select single model randomly, neglecting the internal characters of the forecasting object. After discussing the function of cointegration test and encompassing test in the selection of single model, supplemented by empirical analysis, the paper gives the single model selection guidance: no more than five suitable single models can be selected from many alternative single models for a certain forecasting target, which increases accuracy and stability.

No corporation can gain significant development without profit-making methods, so do third-party payment corporations. Even though third-party payment corporations have huge user group, effective profit mode is still the precondition for the corporations to create greater service value. This paper analyzes the broad prospects of third-party payment platforms, and divides its current profit mode into two stages, i.e., absolutely-free mode to partially-charged mode. Finally, this paper raises four innovative profit modes for third-party payment platform.

The exchange-rate time series is a dynamic non-linear system, whose characteristics cannot be reflected by neither the linear regression model nor the static neutral network. The Nonlinear Autoregressive with eXogenous input (NARX) includes the feedback of the network output, therefore can reflect the dynamic property of the system. This paper analyzed the chaotic property of the exchange-rate time series, calculated the embedding dimension of the series, and established the exchange-rate forecast model using the NARX network. The result shows that the NARX network has better short-term and mid-term forecast effect, comparing to the BP network and the ARIMA model.

Exchange rate time series is often characterized as chaotic in nature. The prediction using conventional statistical techniques and neural network with back propagation algorithm, which is most widely applied, do not give reliable prediction results. Exchange-rate time series is also a dynamic non-linear system, whose characteristics cannot be reflected by the static neutral network. The Nonlinear Autoregressive with eXogenous input (NARX) includes the feedback of the network output, therefore can reflect the dynamic property of the system. This paper proved the chaotic property of the exchange-rate time series, calculated the embedding dimension and time delay of the series, and established the exchange-rate forecast model using the NARX network. The result shows that the NARX network has better short-term forecast effect, comparing to the BP network and the SVM model.

Summary: We present a case study of fracture detection using a 3-D P-wave seismic dataset from the Xujiaweizi (XJWZ) fault depression in the northern Songliao Basin in China. With the discovery of more volcanic gas-bearing reservoirs in XJWZ fault depression, we have realized that the most critical uncertainty in optimizing reservoir production is the location and characterization of the natural fracture system. Traditionally, fracture information comes from well data, in particular, image log (FMI) and core. This paper describes how p-wave azimuthal anisotropy can extend the characterization of fractures in volcanic (and other) rocks to regions between the wells. A major aspect of this study is to compare and contrast on a common dataset the effectiveness of different seismic azimuthal attributes in characterizing fractures and quantify those differences. Results indicate this is an effective approach for fracture detection and characterization in volcanic rocks. The final fracture orientation and density maps calculated from the p-wave azimuthal anisotropy are consistent with FMI interpretation and coring data from drilled wells.

This paper puts forward TPP (third party payment, TPP for short) conception, system architecture and payment model and introduces a new TPP payment solution integrating with modern logistics. This solution can prevent the sellers from buyers' vicious cheating, and make sure the money is received in time. Also, the personal credit mechanism in TPP is discussed to help the customer choose the reputable seller.