试论穆时英小说中的爱情结局模式

穆时英爱情故事的结局以＂分离＂为主,＂分离＂模式又可分死亡模式和分手模式两种。穆时英的＂分离＂模式,是作家个人对爱情的不自信和追求感官刺激的社会风气等因素共同作用的结果。与当时左翼＂革命加恋爱＂模式相比,＂分离＂模式结局是死亡,追求的是幻灭。

Static and dynamic tensile failure characteristics of rock based on splitting test of circular ring

Static and dynamic splitting tests were conducted on ring marble specimens with different internal diameters to study the tensile strength and failure modes with the change of the ratio of internal radius to external radius （ρ） under different loading rates. The results show that the dynamic tensile strength of disc rock specimen is approximately five times its static tensile strength. The failure modes of ring specimens are related to the dimension of the internal hole and loading rate. Under static loading tests, when the ratio of internal radius to external radius of the rock ring is small enough （ρ〈0.3）, specimens mostly split along the diametral loading line. With the increase of the ratio, the secondary cracks are formed in the direction perpendicular to the loading line. Under dynamic loading tests, specimens usually break up into four pieces. When the ratio ρreaches 0.5, the secondary cracks are formed near the input bar. The tensile strength calculated by Hobbs’ formula is greater than the Brazilian splitting strength. The peak load and the radius ratio show a negative exponential relationship under static test. Using ring specimen to determine tensile strength of rock material is more like a test indicator rather than the material properties.

Dynamic compressive strength and failure mechanisms of microwave damaged sandstone subjected to intermediate loading rate

To investigate the influence of microwave heating on the dynamic behavior and failure mechanisms of rock,dynamic compression tests were conducted on microwave-irradiated sandstone specimens using a modified split Hopkinson pressure bar(SHPB)system.Experimental results show that microwave radiation can effectively weaken the compressive strength of sandstone.Rock specimens show three different failure modes under impact load:tensile failure,tensile−shear composite failure and compressive−shear failure.The dynamic Poisson’s ratio,calculated using the measured P-and S-wave velocities,is introduced to describe the deformation characteristics of sandstone.With the increase in microwave power and heating time,the Poisson’s ratio declines first and then increases slightly,and the turning point occurs at 244.6℃.Moreover,the microstructural characteristics reveal that microwave radiation produces dehydration,pore expansion,and cracking of the rock.The damage mechanisms caused by microwave radiation are discussed based on thermal stress and steam pressure inside the rock,which provides a reasonable explanation for the experimental results.

Strain rate sensitivity of closed cell aluminium fly ash foam

With the increasing use of metal foams in various engineering applications, investigation of their dynamic behaviour under varying strain rate is necessary. Closed cell aluminium fly ash foam developed through liquid metallurgy route was investigated for its stress--strain behaviour at different strain rates ranging from 700 s^-1 to 1950 s^-1. The numerical model of split Hopkinson pressure bar （SHPB） was simulated using commercially available finite element code Abaqus/Explicit. Validation of numerical simulation was carried out using available experimental and numerical results. Full scale stress--strain curves wez＇e developed for various strain rates to study the effect of strain rate on compressive strength and energy absorption. The results showed that the closed cell aluminium fly ash foam is sensitive to strain rate.

Heat Transfer in Nucleate Pool Boiling of Binary and Ternary Refrigerant Mixtures

Heat transfer coefficients in nucleate pool boiling were measured on a horizontal copper surface for refrigerants, HFC-134a, HFC-32, and HFC-125, their binary and ternary mixtures under saturated conditions at 0.9MPa. Compared to pure components, both binary and ternary mixtures showed lower heat transfer coefficients.This deterioration was more pronounced as heat flux was increased. Experimental data were compared with some empirical and semi-empirical correlations available in literature. For binary mixture, the accuracy of the correlations varied considerably with mixtures and the heat flux. Experimental data for HFC-32/134a/125 were also compared with available correlated equation obtained by Thome. For ternary mixture, the boiling range of binary mixture composed by the pure fluids with the lowest and the medium boiling points, and their concentration difference had important effects on boiling heat transfer coefficients.

Prediction of Instability Separation Modes and Its Application in Practical Dynamic Security Region

The transient critical boundary of dynamic security region (DSR) can be approximated by a few hyper planes correlated with instability separation modes. A method to fast predict instability separation modes is proposed for DSR calculation in power injection space. The method identifies coherent generation groups by the developed K-medoids algorithm, taking a similarity matrix derived from the reachability Grammian as the index. As an experimental result, reachability Grammian matrices under local injections are approximately invariant. It indicates that the generator coherency identifications are nearly consistent for different injections. Then instability separation modes can be predicted at the normal operating point, while average initial acceleration is considered as the measure of the critical generator group to amend the error. Moreover, based on these predicted instability separation modes, a critical point search strategy for DSR calculation is illustrated in the reduced injection space of the critical generators. The proposed method was evaluated using New England Test System, and the computation accuracy and speed in determining the practical DSR were improved.

Numerical Simulation and Experimental Study on the Performance of Gas/liquid Spiral Separator

The gas/liquid spiral separator, a key component in the compressed air system, was used to remove liquid and oil from gas stream by centrifugal and gravitational forces. To optimize the design of the separator,the relationship between the performance and structural parameters of separators is studied. Computational fluid dynamics (CFD) method is employed to simulate the flow fields and calculate the pressure drop and separation efficiency of air-liquid spiral separators with different structural parameters. The RSM (Reynolds stress model)turbulence model is used to analyze the highly swirling flow fields while the stochastic trajectory model is used to simulate the traces of liquid droplets in the flow field. A simplified calculation formula of pressure drop in spiral structures is obtained by modifying Darcy's equation and verified by experiment.

Spatial patterns of farmland abandonment and its impact factors in the central Three Gorges Reservoir Area

The severe farmland abandonment phenomena in China have tremendously decreased the farmland usage efficiency and caused a series of profound ecological and social outcomes. The complexity of farmland abandonment necessitates a systematic research on its patterns and impact factors to underpin the dynamics of problem as well as potential solutions. This paper took Wanzhou district in the central part of Three Gorges Reservoir Area as an example to study the spatial distribution patterns of abandoned farmland at three scales, i.e., town, village, and plot, and analyzed the influence from labor transfer and farmland circulation. We conducted a survey on the distribution patterns of abandoned farmland via questionnaires at town and village scales, together with the modeling and interpretation of high-resolution aerial images taken by unmanned aerial vehicles at plot scale. Our research discloses a strong relationship between the distribution of abandoned farmland and the distance from population center at different scales. At eithertown or village scale, the abandonment proportion was recognized the highest in mid-distance areas and lowest in close-distance areas, and the per capita area of abandoned farmland increased with the distance to downtown or township. At plot scale, abandonment proportion presented exponential growth with the distance to village center, whereas the abandoned farmland was mainly distributed in the areas with distance above 500 m from the village center. Moreover, we noticed that labor transfer and farmland circulation are two important factors that influence farmland abandonment. Labor's outbound transfer distance has a positive linkage with the possibility of farmland abandonment. Finally, it is recommended that development and adoption of corresponding policies on local urbanization and farmland circulation will facilitate to alleviate farmland abandonment.

New finding on out-of-step separation configuration of large-scale power systems

In this paper,two new concepts—“main out-of-step mode” and “minor out-of-step mode”—are proposed for power system reliability analysis. Large-scale power system studies found that out-of-step generator groups may have characteristics of the main out-of-step mode and the minor out-of-step mode. The generator groups with main out-of-step modes can determine the out-of-step interface of the large-scale power system,while generators with the minor out-of-step modes cannot play such a role. Therefore,the method of capturing the out-of-step interface by seeking the lowest voltage point(the out-of-step center) can only group the generators with the main out-of-step modes,and may fail to combine the generators with the minor out-of-step modes into proper coherent generator groups. Thus,it is necessary in engineering applications to equip the generators that are likely to have the characteristics of the minor out-of-step modes with separation devices based on off-line simulation studies in order to reduce the risk of further accidents caused by these generators after system separation.

Effect of specimen size on energy dissipation characteristics of red sandstone under high strain rate

In this experiment, red sandstone specimens, having slenderness ratios of 0.5, 0.7, 0.9 and 1.1 respectively, were subjected to blow tests using a Split Hopkinson Pressure Bar(SHPB) system at a pressure of 0.4 atmospheres. In this paper, we have analyzed the effect of slenderness ratio on the mechanical properties and energy dissipation characteristics of red sandstone under high strain rates. The processes of compaction, elastic deformation and stress softening deformation of specimens contract with an increase in slenderness ratio, whilst the nonlinear deformation process extends correspondingly. In addition, degrees of damage of specimens reduced gradually and the type of destruction showed a transformation trend from stretching failure towards shear failure when the slenderness ratio increased. A model of dynamic damage evolution in red sandstone was established and the parameters of the constitutive model at different ratios of length to diameter were determined. By comparison with the experimental curve, the accuracy of the model, which could reflect the stress–strain dynamic characteristics of red sandstone, was verified. From the view of energy dissipation, an increase in slenderness ratio of a specimen decreased the proportion of energy dissipation and caused a gradual fall in the capability of energy dissipation during the specimen failure process. To some extent, the study indicated the effects of slenderness ratios on the mechanical properties and energy dissipation characteristics of red sandstone under the high strain rate, which provides valuable references to related engineering designs and academic researches.

Detection of Partial Discharge in Power Transformers Using Rogowski Coil and Multiresolution Analysis

Partial discharge detection in power transformers is discussed using a new approach that exploit the broad band of the Rogowski coils and the potential of two signal processing tools： discrete wavelet transform and empirical mode decomposition. Detecting and analyzing incipient activities of partial discharge can provide useful information to diagnostics and prognostics about transformer insulation. So, partial discharge signals embedded in the electric current at ground conductor are measured using the Rogowski coil. These signals are submitted to noise suppression and the partial discharges waveforms are extracted through different ways： using discrete wavelet transform and using empirical mode decomposition. The comparison of these two methods show that the extraction with discrete wavelet transform results in a faster and simpler algorithm than the empirical mode decomposition. But this one produces more precise waveforms due its adaptive characteristic.

Discretization Approach in Integrated Hydrologic Model for Surface and Groundwater Interaction

The commonly used discretization approaches for distributed hydrological models can be broadly categorized into four types,based on the nature of the discrete components:Regular Mesh,Triangular Irregular Networks(TINs),Representative Elementary Watershed(REWs) and Hydrologic Response Units(HRUs).In this paper,a new discretization approach for landforms that have similar hydrologic properties is developed and discussed here for the Integrated Hydrologic Model(IHM),a combining simulation of surface and groundwater processes,accounting for the interaction between the systems.The approach used in the IHM is to disaggregate basin parameters into discrete landforms that have similar hydrologic properties.These landforms may be impervious areas,related areas,areas with high or low clay or organic fractions,areas with significantly different depths-to-water-table,and areas with different types of land cover or different land uses.Incorporating discrete landforms within basins allows significant distributed parameter analysis,but requires an efficient computational structure.The IHM integration represents a new approach interpreting fluxes across the model interface and storages near the interface for transfer to the appropriate model component,accounting for the disparate discretization while rigidly maintaining mass conservation.The discretization approaches employed in IHM will provide some ideas and insights which are helpful to those researchers who have been working on the integrated models for surface-groundwater interaction.

Determination of trace elements in high purity nickel by high resolution inductively coupled plasma mass spectrometry

The contents ofMg, Al, Si, Ti, Cr, Mn, Fe, Co, Cu, Ga, As, Se, Cd, Sb, Pb and Bi in high purity nickel were determined by high resolution inductively coupled plasma mass spectrometry （HR-ICP-MS）. The sample was dissolved in HNO3 and HCI by microwave digestion. Most of the spectral interferences could be avoided by measuring in the high resolution mode. The matrix effects because of the presence of excess HC1 and nickel were evaluated. Correction for matrix effects was made using Sc, Rh and T1 as internal standards. The optimum conditions for the determination were tested and discussed. The detection limits range from 0.012 to 1.76 ~tg/g depending on the type of elements. The applicability of the proposed method is also validated by the analysis of high purity nickel reference material （NIST SRM 671）. The relative standard deviation （RSD） is less than 3.3%. Results for determination of trace elements in high purity nickel were presented.

Aspect-Oriented Design Method for Embedded Systems Based on Timed Statecharts

The formal modelling and verification method has become an effective way of improving the reliability and correctness of complex,safety-critical embedded systems.Statecharts are widely used to formally model embedded applications,but they do not realise the reasonable separation of system concerns,which would result in code scattering and tangling.Aspect-Oriented Software Development(AOSD)technology could separate crosscutting concerns from core concerns and identify potential problems in the early phase of the software development life cycle.Therefore,the paper proposes aspect-oriented timed statecharts(extended timed statecharts with AOSD)to separately model base functional requirements and other requirements(e.g.,scheduling,error handling),thereby improving the modularity and development efficiency of embedded systems.Furthermore,the dynamic behaviours of embedded systems are simulated and analysed to determine whether the model satisfies certain properties(e.g.,liveness,safety)described by computation tree logic formulae.Finally,a given case demonstrates some desired properties processed with respect to the aspect-oriented timed statecharts model.

少年司法的形成历史与普遍模式探究

本文主要探讨了少年司法制度形成与发展的两种结构性模式．即“分离与累积”模式与“螺旋式循环”模式。第一部分介绍并论述了“分离与累积”模式中少年司法制度形成与发展的若干阶段，同时介绍并明确了日本少年司法制度的形成过程与特点。第二部分考察了在欧美各国及日本正在扩大的重罚化倾向与刑罚主义倾向，在此基础上介绍并分析了“螺旋式循环”模式，并得出结论：少年司法的分离与独立并不是线性发展的，相反，应当将其理解为螺旋式发展的过程。

Flexible PDMS-based triboelectric nanogenerator for instantaneous force sensing and human joint movement monitoring

Flexible wearable sensors with excellent electric response and self-powered capability have become an appealing hotspot for personal healthcare and human-machine interfaces.Here,based on triboelectric nanogenerator(TENG),a flexible self-powered tactile sensor composed of micro-frustum-arrays-structured polydimethylsiloxane(PDMS)film/copper(Cu)electrodes,and poly(vinylidenefluoride-trifluoroethylene)(P(VDF-TrFE))nanofibers has been demonstrated.The TENG-based self-powered tactile sensor can generate electrical signals through the contact-separation process of two triboelectric layers under external mechanical stimuli.Due to the uniform and controllable micro-frustum-arrays structure fabricated by micro-electro-mechanical system(MEMS)process and the P(VDF-TrFE)nanofibers fabricated by electrostatic spinning,the flexible PDMS-based sensor presents high sensitivity of 2.97 V kPa^-1,stability of 40,000 cycles(no significant decay),response time of 60 ms at 1 Hz,low detection pressure of a water drop(~4 Pa,35 mg)and good linearity of 0.99231 in low pressure region.Since the PDMS film presents ultra-flexibility and excellent-biocompatibility,the sensor can be comfortably attached on human body.Furthermore,the tactile sensor can recognize various types of human body movements by the corresponding electrical signals.Therefore,the as-prepared TENGs are potential on the prospects of gesture detection,health assessment,human-machine interfaces and so on.

Optimal mode of capillary electrophoresis for the impurity analysis of β-lactam antibiotics

In order to determine the optimal mode of capillary electrophoresis for the impurity control of β-lactam antibiotics, different modes and various electrophoresis conditions for the separation of impurities were compared.The results showed that micellar electrokinetic capillary chromatography（MEKC） was the optimal separation mode for the impurity profiling of β-lactam antibiotics.In MEKC,not only the common R and S isomers,Δ-2 andΔ-3 isomers,and Z and E isomers,but also the impurities of β-lactam antibiotics could be well separated compared with the capillary zone electrophoresis.Therefore,MECK is the first choice for the separation of impurities of β-lactam antibiotics with capillary electrophoresis（CE）.The optimal separation could be achieved in MEKC by optimizing the pH and the concentrations of buffered saline,micelles and organic solvent（methanol） in running buffer.

Control of the Asymmetric Flow in Rocket Nozzles

In some rocket nozzle flows, the existence of the transition from FSS to RSS and the occurrence of asymmetric flow are known in previous researches. As a result, the transition causes excessive side-loads that may damage the nozzle. Thus, it is important to investigate the method in order to control the asymmetric flow separation. In the present study, the relationship between the asymmetric separation and the rate of change of the pressure ratio with time was investigated from the point of view of the transition from FSS to RSS in the supersonic nozzle experimentally. Further, change of the flow separation by using step and cavity, and the possibility of the control was demonstrated. As a result, it was shown that the method using a cavity was effective for the control of the separation pattern.

Comparisons between centrifuge and numerical modeling results for slope toppling failure

This paper presents series studies on the toppling mechanism by centrifuge tests and numerical simulations. Two different discrete element methods, i.e., the continuum-based discrete element method(CDEM) and the discontinuous deformation analysis(DDA), are adopted. The modeling results show that both the methods can accurately capture the failure modes of the centrifuge tests, including three distinct zones and two failure surfaces. Comparisons are made between the physical test and numerical simulation results. The critical inclination angle of the tilting table where the slope models are fixed on can be moderately predicted by the two methods, with different degrees of precision. The error between the test results and the simulated results is within 1% for the slope models without rock-bridges by both CDEM and DDA. However, it is amplified for the staggered-joint models that simulate the rock-bridges. With DDA, the average error is about 5%, and the maximum error is up to 17%. While with CDEM, the errors for the aligned-joint models are ranged from 1% to 6%, and it is from 10% to 29% for the staggered-joint models. The two numerical methods show the capability in simulating toppling failure of blocky rock mass with and without rock-bridges. The model with rock-bridges which provides a certain bending resistance is more stable than the one without any rock-bridge. In addition, the two failure surfaces were observed, which is different from the common understanding that only one failure surface appears.

Effects of angle of attack on wing rock motion induced by the flows over slender body with low swept wing

The patterns of wing rock motion at 52.5° angle of attack have already been investigated in detail （Rong, 2009; Wang, 2010）. These patterns are completely different from those at other angles of attack. This phenomenon indicates that angle of attack affects wing rock motion. The present study alms to examine the different patterns of wing rock motion at different angles of attack. The flow mechanisms of the motion patterns are also revealed, especially the uncommanded lateral motions, including wing rock and lateral deflection, induced by regular asymmetric separated flow from wings at low angles of attack and fore- body asymmetric vortices at angles of attack of 27.5°〈 α 〈 70°. The test conditions, including the testing Reynolds number, wind tunnel, experimental techniques, and test model, are all the same as those used in a previous study at a = 52.5°. Finally, the experimental technique of rotating nose of the model to suppress the wing rock or lateral deflection, which is induced by forebody asymmetric vortex flow, is applied. The uncommanded lateral motions are successfully suppressed by this technique.