高压纳秒级双快源研究

试验用高压场效应管作为开关器件,做成脉冲幅度大于4kV、前后沿5ns左右的高压快脉冲源。介绍了该脉冲源的电路结构,着重从高压场效应管的开关基理,场效应管栅极的“过”驱动,多管串联等几方面分析了提高脉冲源输出特性的方法和途径。

Data-driven intelligent monitoring system for key variables in wastewater treatment process

In wastewater treatment process(WWTP), the accurate and real-time monitoring values of key variables are crucial for the operational strategies. However, most of the existing methods have difficulty in obtaining the real-time values of some key variables in the process. In order to handle this issue, a data-driven intelligent monitoring system, using the soft sensor technique and data distribution service, is developed to monitor the concentrations of effluent total phosphorous(TP) and ammonia nitrogen(NH_4-N). In this intelligent monitoring system, a fuzzy neural network(FNN) is applied for designing the soft sensor model, and a principal component analysis(PCA) method is used to select the input variables of the soft sensor model. Moreover, data transfer software is exploited to insert the soft sensor technique to the supervisory control and data acquisition(SCADA) system. Finally, this proposed intelligent monitoring system is tested in several real plants to demonstrate the reliability and effectiveness of the monitoring performance.

Walter Benjamin： A New Positive Concept of Destruction

The author＇s proposal is to show how an apparently marginal text by Walter Benjamin, ＂The Destructive Character＂, can be taken as a hermeneutic model for understanding the connection of Benjamin＇s with history and tradition and for characterizing his thought as philosophy of threshold. It is the author＇s intention to show how the destructive character, on the threshold between destruction and construction, succeeds in remaining in that transition area that announces a change, showing its creative and conservative features; thus it appears as a figure of coexistence between stillness and movement, passage and interruption, and past and future. What the author wants to point out is that, in the description of this figure, Benjamin is driven by a cognitive demand, which tends to focalize the process of destruction itself rather than the result of the destruction process. The space in which the destructive character is acting is the space of the possibility of change and emancipation, and the space where it is possible to keep together past and future, and memory and redemption. Starting from these reflections, an important question arises about the problem of the relation between history and tradition, and culture and its memory： Neither the destruction of memory by a culture nor its canonization is meaningful. The concept of destructive character then represents a preferential point of observation for analyzing the articulations of Benjamin＇s thought. From this perspective, a decisive point of Benjamin＇s reflection seems to emerge on one side, strengthened in the permeation of Hebraic ancestors between destruction and salvation; on the other side, some of the concepts and images of the Berliner philosopher seem to show up in a new light.

On Implementing a Simulated Moment of Inertia in a Reduced Scale Brake Dynamometer

This paper describes the implementation of brake procedures with simulated inertia on a reduced scale brake dynamometer For this purpose, the theoretical foundations are first explained, and test measurements are carried out. The results show good agreement between calculated and measured accelerations during brake applications. Furthermore, braking processes with various driver models were carried out using associated normal force functions, and examined with regard to their coefficients of friction. A clear difference between these models can be observed. This introduces the possibility for new measurement methods for the analysis of NVH-behavior in brake systems. This work is the first step towards identifying a transfer function between full- and reduced-scale brake dynamometers. In a second step, the temperature scaling must be taken into account. Based on these results, it is possible to isolate the influences of the braking system components from those of the dynamics of the friction coefficient in the boundary layer.

Kinetic Behavior of Exchange-Driven Growth with Catalyzed-Birth Processes

Two catalyzed-birth models of n-species （n ≥ 2） aggregates with exchange-driven growth processes are proposed and compared. In the first one, the exchange reaction occurs between any two aggregates Ak^m and Af^m of the same species with the rate kernels Km（k,j）= Kmkj （m = 1, 2,... ,n, n ≥ 2）, and aggregates of A^n species catalyze a monomer-birth of A^l species （l = 1, 2 , n - 1） with the catalysis rate kernel Jl（k,j） -Jlkj^v. The kinetic behaviors are investigated by means of the mean-field theory. We find that the evolution behavior of aggregate-size distribution ak^l（t） of A^l species depends crucially on the value of the catalysis rate parameter v： （i） ak^l（t） obeys the conventional scaling law in the case of v ≤ 0, （ii） ak^l（t） satisfies a modified scaling form in the case of v 〉 0. In the second model, the mechanism of monomer-birth of An-species catalyzed by A^l species is added on the basis of the first model, that is, the aggregates of A^l and A^n species catalyze each other to cause monomer-birth. The kinetic behaviors of A^l and A^n species are found to fall into two categories for the different v： （i） growth obeying conventional scaling form with v ≤ 0, （ii） gelling at finite time with v 〉 0.

Numerical Simulation of Direct-contact Condensation from a Supersonic Steam Jet in Subcooled Water

The phenomenon of direct-contact condensation,used in steam driven jet injectors,nuclear reactor emergency core cooling systems and direct-contact heat exchangers,was investigated computationally by introducing a thermal equilibrium model for direct-contact condensation of steam in subcooled water.The condensation model presented was a two resistance model which takes care of the heat transfer process on both sides of the interface and uses a variable steam bubble diameter.The injection of supersonic steam jet in subcooled water tank was simulated using the Euler-Euler multiphase flow model of Fluent 6.3 code with the condensation model incorporated. The findings of the computational fluid dynamics（CFD） simulations were compared with the published experimental data and fairly good agreement was observed between the two,thus validating the condensation model.The results of CFD simulations for dimensionless penetration length of steam plume varies from 2.73-7.33,while the condensation heat transfer coefficient varies from 0.75-0.917 MW·（m ^2 ·K）^ -1 for water temperature in the range of 293-343 K.

Landscape Pattern Evolution Processes of Alpine Wetlands and Their Driving Factors in the Zoige Plateau of China

Zoige Plateau wetlands are located in the northeastern corner of the Qinghai-Tibet Plateau.The landscape pattern evolution processes in the Zoige Plateau and their driving factors were identified by analyzing the dynamic changes in landscape modification and conversion and their dynamic rates of alpine wetlands over the past four decades.The results showed that the landscape conversion between wetlands and non-wetlands mainly occurred during the period from 1966 to 1986.The marsh wetland area converted from lake and river wetlands was larger because of swamping compared to other wetland landscapes.Meanwhile,the larger area of marsh wetlands was also converted to lake wetlands more than other types of wetlands.The modification processes mainly occurred among natural wetland landscapes in the first three periods.Obvious conversions were observed between wetland and nonwetland landscapes(i.e.,forestland,grassland,and other landscapes) in the Zoige Plateau.These natural wetland landscapes such as river,lake and marsh wetlands showed a net loss over the past four decades,whereas artificial wetland landscapes(i.e.,paddy field and reservoir and pond wetlands) showed a net decrease.The annual dynamic rate of the whole wetland landscape was 0.72%,in which the annual dynamic rate of river wetlands was the highest,followed by lake wetlands,while marsh wetlands had the lowest dynamic rate.The integrated landscape dynamic rate showed a decreasing trend in the first three periods.The changes in wetland landscape patterns were comprehensively controlled by natural factors and human activities,especially human activities play an important role in changing wetland landscape patterns.

Spatial and Temporal Variability of Water Availability in the Yellow River Basin

The changes in hydrological processes in the Yellow River basin were simulated by using the Community Land Model(CLM,version 3.5),driven by historical climate data observed from 1951 to 2008.A comparison of modeled soil moisture and runoff with limited observations in the basin suggests a general drying trend in simulated soil moisture,runoff,and precipitation-evaporation balance(P-E) in most areas of the Yellow River basin during the observation period.Furthermore,annual soil moisture,runoff,and P-E averaged over the entire basin have declined by 3.3%,82.2%,and 32.1%,respectively.Significant drying trends in soil moisture appear in the upper and middle reaches of the basin,whereas a significant trend in declining surface runoff and P-E occurred in the middle reaches and the southeastern part of the upper reaches.The overall decreasing water availability is characterized by large spatial and temporal variability.

A Comparative Study of Structural Composition Methods and Techniques

In software engineering as in all other engineering fields, the product to be built is divided into sub-parts that are independently constructed and subsequently assembled. This procedure reduces the complexity and improves the reuse of the developed products. MDE （model-driven engineering） is a recent initiative that adopts this approach. In this context, model composition has become an important artifact in the MDE domain that allows constructing and composing an efficient assembly process. This paper will attempt to identify the strength and the drawbacks of the existing composition model paradigms, and determine the various parameters that govern their behavior.

Process optimization with consideration of uncertainties——An overview

Optimization under uncertainty is a challenging topic of practical importance in the Process Systems Engineering.Since the solution of an optimization problem generally exhibits high sensitivity to the parameter variations, the deterministic model which neglects the parametric uncertainties is not suitable for practical applications. This paper provides an overview of the key contributions and recent advances in the field of process optimization under uncertainty over the past ten years and discusses their advantages and limitations thoroughly. The discussion is focused on three specific research areas, namely robust optimization, stochastic programming and chance constrained programming, based on which a systematic analysis of their applications, developments and future directions are presented. It shows that the more recent trend has been to integrate different optimization methods to leverage their respective superiority and compensate for their drawbacks. Moreover, data-driven optimization, which combines mathematical programming methods and machine learning algorithms, has become an emerging and competitive tool to handle optimization problems in the presence of uncertainty based on massive historical data.

Study on Supply Drive and Demand Drive of the Telecommunication Operation

This paper analyzes the total movement period of the development of the world telecommunication industry, and points out the basic principles of the supply and demand regulation and the market drive are important and useful to the telecommunication industry. The thesis puts forward the pertinent evaluation and the positive suggestions according to the general characteristics and individual characteristics of Chinese telecommunication industry and emphasizes the meaning of the demand drive.

Host Engineering for Red Electrophosphorescent Devices

In this paper, we demonstrate that controlled dopantoncentration is an essential issue for charge carriers transporting in red Phosphorescent Organic Light-Emitting Device （PHOLED）. Carriers transport via dopant molecules in the emitting layer with a single host, however, via both dopant and host molecules when their energy levels are well aligned. Conditions for reduced driving-voltage and enhanced efficiency of red PHOLED are obtained by employing a mixed host structure. A pure red PHOLED with color coordinates of （0.67, 0.33） has been realized by using only 4 wt% dopant, The device achieves 100 cd/cm2 at 2.9 V, with correspond- ing power efficiency of 9.3im/W and external quantum efficiency of 14.3%.

Experimental Investigation of Electric Drive Dynamics

Induction motor is used in many applications to drive an electromechanical system. Transients of the motor torque and speed are outlined by the inertia of rotating rotor. The paper deals with influence of rotor inertia to transients of motor speed. The method of speed control measurement and experimental equipment is discussed. Simulation and experimental results are compared.

Sixteen Years of Trastuzumab Use： Complete Response in Lung, Bone, and CNS Metastasis from Breast Cancer

Although metastatic breast cancer is considered as an incurable disease, various biological drivers influence the outcomes. The use of trastuzumab in patients overexpressing HER（human epidermal growth factor receptor 2）-2 increases long-term survival even in those patients who developed brain metastasis. Nevertheless, special attention must be paid to the risk of cardiotoxicity. We report the case of a young woman with HER-2-positive breast cancer with bone and lung disease who developed brain metastasis during treatment with trastuzumab. The treatment has been continued and she is alive and in complete remission after 16 years.

Eros and Thanatos in the Psychical Process of Paul Morel： Diversity in Paul＇s Psyche

This paper attempts to analyze Paul Morel＇s instinctual drives--in D. H. Lawrence＇s Sons and Lovers （2006}---toward survival, neurotic refusal to accept life, and his will to give life meaning after a fierce and prolonged internal strife--in the light of psychoanalysis. It will explore how his ＂Id＂ strives to bring about the satisfaction of instinctual needs on the basis of the pleasure principle driving him to seek pleasure. His ＂libido＂--psychic energy, emanating from the id, especially the sexual urge--has empowered his ＂Eros＂ or life instinct. It will also explore how ＂Thanatos＂ or death instinct, in contrast, has yearned for an almost lifeless state and curbed entering into human relationships as experienced in his last rejection of Miriam after his mother＇s death leaving a great trauma on Paul who has been on the verse of extinction as a result. Therefore, Eros and Thanatos, both coincide and conflict within him, are dynamically involved and thus are interacted infusing life not stagnation in Paulin consequence

Successful couplings for a class of stochastic differential equations driven by Lvy processes

By constructing proper coupling operators for the integro-differential type Markov generator, we establish the existence of a successful coupling for a class of stochastic differential equations driven by Levy processes. Our result implies a new Liouville theorem for space-time bounded harmonic functions with respect to the underlying Markov semigroups, and it is sharp for Ornstein-Uhlenbeck processes driven by s-stable Levy processes.

Driving force planning in shield tunneling based on Markov decision processes

In shield tunneling, the control system needs very reliable capability of deviation rectifying in order to ensure that the tunnel trajectory meets the permissible criterion. To this goal, we present an approach that adopts Markov decision process (MDP) theory to plan the driving force with explicit representation of the uncertainty during excavation. The shield attitudes of possi- ble world and driving forces during excavation are scattered as a state set and an action set, respectively. In particular, an evaluation function is proposed with consideration of the stability of driving force and the deviation of shield attitude. Unlike the deterministic approach, the driving forces based on MDP model lead to an uncertain effect and the attitude is known only with an imprecise probability. We consider the case that the transition probability varies in a given domain estimated by field data, and discuss the optimal policy based on the interval arithmetic. The validity of the approach is discussed by comparing the driving force planning with the actual operating data from the field records of Line 9 in Tianjin. It is proved that the MDP model is reasonable enough to predict the driving force for automatic deviation rectifying.

Numerical Simulation of 2-D Radiation-Drive Ignition Implosion Process

A Lagrangian compatible radiation hydrodynamic algorithm and the nuclear dynamics computing module are developed and implemented in the LARED Integration code, which is a radiation hydrodynamic code based on the 2-D cylindrical coordinates for the numerical simulation of the indirect-drive Inertial Confined Fusion. A number of 1-D and 2-D ignition implosion numerical simulations by using the improved LARED Integration code (ILARED) are presented which show that the 1-D numerical results are consistent with those computed by the 1-D radiation hydrodynamic code RDMG, while the simulation results of the 2-D low-mode radiative asymmetry and hydrodynamic instability growth,according to the physical analysis and anticipation, are satisfactory. The capsules driven by the sources from SGII experiments are also simulated by ILARED, and the fuel shapes agree well with the experimental results. The numerical simulations demonstrate that ILARED can be used in the simulation of the 1-D and 2-D ignition capsule implosion using the multi-group diffusion model for radiation.

Test for autocorrelation change in discretely observed Ornstein-Uhlenbeck processes driven by Lévy processes

In this paper, we consider the problem of testing for an autocorrelation change in discretely observed Ornstein-Uhlenbeck processes driven by Levy processes. For a test, we propose a class of test statistics constructed by an iterated cumulative sums of squares of the difference between two adjacent observations. It is shown that each of the test statistics weakly converges to the supremum of the square of a Brownian bridge. The test statistics are evaluated by some empirical results.

Gradient estimates and coupling property for semilinear SDEs driven by jump processes

Let L be a L′evy process with characteristic measureν,which has an absolutely continuous lower bound w.r.t.the Lebesgue measure on Rn.By using Malliavin calculus for jump processes,we investigate Bismut formula,gradient estimates and coupling property for the semigroups associated to semilinear SDEs forced by L′evy process L.