单独采用等效多相制整流治理谐波

总结了采用不加装滤波器的等效多相制整流抑制谐波的效果和应用条件,并介绍了相应设备的设计要求。

“相国”、“丞相”官称考

自《汉书·百官公卿表》“相国、丞相皆秦官”的观点出现后,引出了古往今来关于春秋战国“相国”“丞相”官称的许多不同看法:如《汉官仪》说“相国、丞相皆六国时官”;《通典》说“始皇始置相国”;《历代职官表》说“相国在丞相之上”,等等。安作璋、熊铁基先生新著《秦汉官制史稿》(齐鲁书社1984年1月版),一反上述传统说法,认为:“所有记载中的‘相国’二字。

Modulation classification of MPSK signals based on nonparametric Bayesian inference

A nonparametric Bayesian method is presented to classify the MPSK （M-ary phase shift keying） signals. The MPSK signals with unknown signal noise ratios （SNRs） are modeled as a Gaussian mixture model with unknown means and covariances in the constellation plane, and a clustering method is proposed to estimate the probability density of the MPSK signals. The method is based on the nonparametric Bayesian inference, which introduces the Dirichlet process as the prior probability of the mixture coefficient, and applies a normal inverse Wishart （NIW） distribution as the prior probability of the unknown mean and covariance. Then, according to the received signals, the parameters are adjusted by the Monte Carlo Markov chain （MCMC） random sampling algorithm. By iterations, the density estimation of the MPSK signals can be estimated. Simulation results show that the correct recognition ratio of 2/4/8PSK is greater than 95% under the condition that SNR 〉5 dB and 1 600 symbols are used in this method.

Gold-containing metal nanoparticles for catalytic hydrogen generation from liquid chemical hydrides

Liquid chemical hydrides, which store hydrogen in the form of chemical bonds, are considered one of the most promising classes of hydrogen storage materials. Their application depends heavily on the development of efficient catalytic systems. Gold‐containing metal nanoparticles have exhibited excellent catalytic performance for hydrogen generation from liquid chemical hydrides. The present mini‐review focuses on recent developments in hydrogen generation from liquid chemical hydrides using gold‐nanoparticle and gold‐containing heterometallic nanoparticle catalysts.

Effect of phase noise in an OFDM/OQAM system

The performance of an OFDM/OQAM system under phase noise is analyzed. The analysis helps to direct the design of low cost tuners through specifying the required phase noise characteristics. Discrete time formulation of OFDM/OQAM is first derived with the square root raised cosine (SRRC) filter as the pulse-shaping filter. Then the effect of multiplicative phase noise is equivalently represented as additive white Gaussian noise (AWGN), the variance of which is given analytically. We can observe that the same result as OFDM/QAM system is derived. Lastly, all the analytical results are verified by the bit error rate (BER) degradation through Monte Carlo simulation.

Full life cycle characterization strategies for spatiotemporal evolution of heterogeneous catalysts

The sustainable development of the chemical industry requires novel and efficient catalysts and catalytic processes,especially eco-friendly and intrinsically safe processes.The idea is to improve the selectivity,activity,and stability of the catalyst in an appropriate reactor.Therefore,it is of great academic and industrial significance to conduct in-situ characterization of a working catalyst while testing its catalytic performance.This is beneficial for a comprehensive study on the dynamic evolution of the catalyst structure under real conditions,deepening the understanding of the structure-performance relationship of catalysts,and providing a scientific basis for the development of future generation catalytic technology.Thus far,it is still a great challenge to realize full life cycle characterization of heterogeneous catalysts from catalyst formation and function to deactivation under real world conditions.In this mini review,we summarize the characterization strategies for heterogeneous catalysts,using zeolite,metal,and metal oxide catalysts as typical examples.The research strategies for the approximation of industrial conditions,multi-scale in-situ characterization devices,and computational modeling of realistic conditions should provide insight for the research and development of industrial catalysis.

Research on Modulation Strategies Based on Multilevel Inverter Universal Hybrid Topology

Based on multi-module-cascaded inverter topology, this study presented a universal multilevel inverter hybrid topology and unified the researches on multilevel inverter topology. According to the freedom of this universal topology, several new hybrid topologies were constructed. Also, based on conventional modulation strategies- multi-carrier SPWM (Sinusoidal Pulse Width Modulation), hybrid modulation strategies were introduced corresponding to hybrid topologies, and a multilevel SVPWM (Space Vector Pulse Width Modulation) technique based on phase-shifted theory was naturally produced. Simulation and experiment results prove that hybrid topologies and corresponding modulation strategies are valid, which lay a foundation for practical application of hybrid multilevel inverter topologies.

Preparation of Highly Squeezed States and Multi—component Entangled Coherent States via the Raman Interaction

A method is presented for generating highly squeezed states of a cavity field via the atom-cavity field interaction of the Raman type. In the scheme a sequence of three-level -type atoms interacts with a cavity field, displaced by a classical source, in a Raman manner. Then the atomic states are measured. By this way the cavity field may collapse onto a superposition of several coherent states, which exhibits strong squeezing. The scheme can also be used to prepare superpositions of many two-mode coherent states for two cavity fields. The coherent states in each mode are on a straight line. This is the first way for preparing multi-component entangled coherent states of this type in cavity QED.

GRADIENT OF REFERENCE DIFFERENCE BASED MATCHING ALGORITHM FOR IMAGE FEATURE POINT

During matching on feature point, gray correlation matching technology is utilized to extract multi-peaks as a coarse matching set. A pair of given corresponding reference points within the left and right images is used to calculate gradients of reference difference between the reference points and each feature point within the multi-peaks set. The unique correspondence is determined by criterion of minimal gradients of reference difference. The obtained correspondence is taken as a new pair of reference points to update the reference points continuously until all feature points in the left (or right) image being matched with the right (or left) image. The gradients of reference difference can be calculated easily by means of pre-setting a pair of obvious feature points in the left and right images as a pair of corresponding reference points. Besides, the efficiency of matching can be improved greatly by taking the obtained matching point as a new pair of reference points, and by updating the reference point continuously. It is proved that the proposed algorithm is valid and reliable by 3D reconstruction on two pairs of actual natural images with abundant and weak texture, respectively.

Fabrication of integrated resistors in printed circuit boards

In order to utilize integrated passive technology in printed circuit boards （PCBs）, manufacturing processing for integrated resistors by lamination method was investigated. Integrated resistors fabricated from Ohmega technologies in the experiment were 1 408 pieces per panel with four different patterns A, B, C and D and four resistance values of 25, 50, 75 and 100 fL Six panel per batch and four batches were performed totally. The testing was done for 960 pieces of integrated resistors randomly selected with the same size. The value distribution ranges and the relative standard deviation （RSD） show that the scatter degree of the resistance decreases with the resistor size increasing and/or with the resistance increasing. Patterns D with resistance of 75 and 100% for four patterns have the resistance value variances less than 10%. Patterns C and D with resistance of 100 Ω have the manufacturing tolerance less than 10%. The process capabilities are from about 0.6 to 1.6 for the designed testing patterns, which shows that the integrated resistors fabricated have the potential to be used in multilayer PCBs in the future.

Dynamic Visualization Approach of the Multiphase Flow Using Electrical Capacitance Tomography

Identifying the flow patterns is vital for understanding the complicated physical mechanisms in multiphase flows.For this purpose,electrical capacitance tomography(ECT) technique is considered as a promising visualization method for the flow pattern identification,in which image reconstruction algorithms play an important role.In this paper,a generalized dynamic reconstruction model,which integrates ECT measurement information and physical evolution information of the objects of interest,was presented.A generalized objective functional that simultaneously considers the spatial constraints,temporal constraints and dynamic evolution information of the objects of interest was proposed.Numerical simulations and experiments were implemented to evaluate the feasibility and efficiency of the proposed algorithm.For the cases considered in this paper,the proposed algorithm can well reconstruct the flow patterns,and the quality of the reconstructed images is improved,which indicates that the proposed algorithm is competent to reconstruct the flow patterns in the visualization of multiphase flows.

Numerical investigation of confined swirling gas-solid two phase jet

This paper presents a \%k\|ε\|k\-p\% multi\|fluid model for simulating confined swirling gas\|solid two phase jet comprised of particle\|laden flow from a center tube and a swirling air stream entering the test section from the coaxial annular. A series of numerical simulations of the two\|phase flow of 30 μm, 45 μm, 60 μm diameter particles respectively yielded results fitting well with published experimental data.

Importance, features and uses of metal oxide catalysts in heterogeneous catalysis

This short review paper aims at assembling the present state of the art of the multiuses of metal oxides in heterogeneous catalysis, concerning liquid and gaseous phases of the reactant mixtures on solid catalysts. It includes the description of the main types of metal oxide catalysts, of their various preparation procedures and of the main reactions catalysed by them (acid-base type, selective and total oxidations, bi-functional catalysis, photocatalysis, biomass treatments, environmental catalysis and some of the numerous industrial applications). Challenges and prospectives are also discussed.

Vector Control Scheme of Five-Phase Induction Machines under Open-Circuit Phase Faults

Multiphase induction machine is normally controlled using rotor field oriented vector control. Under phase（s） loss, the machine currents can be optimally controlled to satisfy certain optimization criteria. In this paper, a vector control scheme to a five-phase induction machine is introduced to ensure equal phase currents and minimum torque ripples under a phase open circuit. The controller idea can be extended to any number of phases with any number of open phases. The fundamental dq components of the stator voltage are obtained using only two PI controllers for the fundamental sequence plane, as in conventional vector control of three-phase machines. Based on steady state model, a simple expression is derived to estimate the required dq voltage components of other sequence planes to ensure equal stator phase currents and minimum torque ripple. A five-phase machine is simulated using MATLAB/Simulink to ensure controller validity.

Low Dynamic Range Solutions to the High Dynamic Range Imaging Problem

While capturing a real world scene using a common digital camera, due to limitations of the sensor dynamic range, we will not be able to capture the entire dynamic range of the some. This problem is evident while capturing a picture of a some which has both brightly and poorly illuminated regions. High Dynamic Range （HDR） imaging aims to recover the entire dynamic range of the scene by compositing multi-exposure images. Tone reproduction is required for displaying HDR images as the corresponding Low Dynamic Range（LDR） images on common displays. This paper discusses novel approaches to reconstruct LDR images directly from multi-exposure images. It is assumed that there is no knowledge of camera response function and other camera settings. At last, it is explained how this task can be achieved effectively for static and dynamic scenes.

Kinetics of the Double Carbonylation of Benzylchloride

It is a multi-phase-catalyzed reaction to produce calcium phenylpyruvate by double carbonylation of benzylchloride. Based on the analysis of the reaction mechanism, a kinetic model of the carbonylation reaction was obtained. The model was verified through experiments in which the diffusion effect was neglected with the appropriate operation manner. But it is inevitable that the carbonylation process is controlled by diffusion as the autoclave scaling up.

Generalized nested logit-based stochasticuser equilibrium model with distance constraint of electric vehicles

Considering the range anxiety issue caused by the limited driving range and the scarcity of battery charging stations,the conventional multinomial logit(MNL)model with the overlapping path issue was used in route choice modeling to describe the route choice behavior of travelers effectively.Furthermore,the generalized nested logit-based stochastic user equilibrium(GNL-SUE)model with the constraints of multiple user classes and distance limits was proposed.A mathematical model was developed and solved by the method of successive averages.The mathematical model was proven to be analytically equivalent to the modified GNL-SUE model,and the uniqueness of the solution was also confirmed.The proposed mathematical model was tested and compared with the GNL-SUE model without a distance limit and the MNL-SUE model with a distance limit.Results show that the proposed mathematical model can effectively handle the range anxiety and overlapping path challenges.

The changes of polyphenolic contents in two kinds of Terminalia chebula Retz.traditional Tibetian processing methods

Taking Terminalia chebula Retz. as the control product, the polyphenolic contents of the processed products in Tibetian, Rubia cordifolia L. processed Terminalia chebula Retz. and Euphorbia fischeriana Steud processed Terminalia chebula Retz. were analyzed by HPLC. Polyphenolic contents increased from 4.54% to 5.69% and 7.46%, respectively, which may lead to the change in their pharmacological effects.

Blind equalization and automatic modulation classification based on subspace for subcarrier MPSK optical communications

Equalization can compensate channel distortion caused by channel multipath effects, and effectively improve convergent of modulation constellation diagram in optical wireless system. In this paper, the subspace blind equalization algorithm is used to preprocess M-ary phase shift keying(MPSK) subcarrier modulation signal in receiver. Mountain clustering is adopted to get the clustering centers of MPSK modulation constellation diagram, and the modulation order is automatically identified through the k-nearest neighbor(KNN) classifier. The experiment has been done under four different weather conditions. Experimental results show that the convergent of constellation diagram is improved effectively after using the subspace blind equalization algorithm, which means that the accuracy of modulation recognition is increased. The correct recognition rate of 16 PSK can be up to 85% in any kind of weather condition which is mentioned in paper. Meanwhile, the correct recognition rate is the highest in cloudy and the lowest in heavy rain condition.