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All-inorganic CsPbX3 (X = I, Br) perovskites without organic component are promising for long-term stability but face main challenges of facile fabrication and phase stability. Here we discover a general organic methylamine acetate salt mediated growth method to deposit high quality phase pure and stable CsPbX3 (X = I, Br) perovskite films via a novel precursor consisting of stoichiometric cesium acetate (CsAc), methylamine halide (MAX) and lead halide (PbX2). Interestingly, these organic salts of CsAc and MAX could efficiently promote the crystallization process especially lower the crystallization temperature, but do not introduce the incorporation of organic MA cation into all-inorganic CsPbX3 perovskites. These phase pure and stable CsPbX3 perovskites with tunable band gaps can be fabricated into high efficiency photovoltaics. Our organic salt mediated growth of all-inorganic perovskite not only reveals the all-inorganic CsPbX3 perovskite’s unique crystal growth mechanism but also demonstrates their promising application for photovoltaics.

Modular multilevel converters (MMCs) have extensive applications and increasing power occupancy in power systems, and various improved topologies with dc fault blocking capability have been developed. The control, dynamic behaviour, and topology of MMCs require significant consideration when building MMC models for power-system-level simulation. In this study, a universal terminal model (UTM) that is suitable for various MMC topologies and can be renewed by simply setting two indexes without changing the circuit structure is proposed. The complicated arm circuit structure can be simplified with the aid of auxiliary components, such as diodes, ideal switches, and controlled voltage sources. Arm dynamics, including cumbersome sub-module switching actions, can be averaged by disregarding the differences among sub-modules and the effect of modulation and capacitor voltage balancing. The proposed UTM exhibits high accuracy and efficiency and thus beneficial for investigating power-system-level issues. In addition, UTM can avoid repetitive and duplicate modelling efforts when the MMC topology changes. The UTMs of MMC based on half-bridge, clamp-double, and full-bridge sub-module are built. Simulation results of comparisons between detailed models and UTMs validate the accuracy and efficiency of the proposed models.

In the background of Voltage Source Converter HVDC (VSC-HVDC) gradually coming into practice, fault ride-through control for wind farm connected to a VSC-HVDC system can maintain system stability, but also impact on the wind generators. To study on fault ride-through problem for wind generators in a VSC-HVDC system, this paper establishes a simulation model of two-terminal VSC-HVDC system including detailed model of wind farm with squirrel-cage induction generators (SCIG) or doubly-fed induction generators (DFIG) in PSCAD/EMTDC, and verifies frequency increase and voltage reduction fault ride-through method for wind farm connected to a VSC-HVDC system. Furthermore, the paper studies performances of different kinds of wind generators with different fault ride-through methods, thus drawing the law of impacts of fault ride-through control on wind generators. The conclusions can provide different kinds of wind generators in a VSC-HVDC system with operation reference for choosing fault ride-through method and reference for simulation study.

A Cascaded transformerless Static Synchronous Compensator (STATCOM) of 35kV/8Mvar has been successfully developed and putted into application. The STATCOM is self-excited and in star configuration, each phase consists of twenty-one units, which employees 3.3kV IGBTs. With power supply by itself and the adjacent one, each unit can be bypassed and thus implement N-1 redundant running. By optimized Carrier Phase-Shift PWM method, the frequency of STATCOM can be dropped as low as 275Hz with the efficiency as high as 99%. Based on high speed distributed digital processors and instant current control method, the device has realized synthesized voltage and reactive power regulation and VQC/AVC coordination. The response time of STATCOM is below 10ms when voltage sag detected, thus strongly sustain the power system voltage. The experimental data and the field operation results both show that the performances of the developed transformerless 35kV/8Mvar STATCOM are satisfied, which provides a new solution for voltage and reactive power control for electric power substation.

In the rock fragmentation process, the disc cutter, tunnel boring machine’s main rock-breaking tool, often lose rock-breaking capability because of the improper selection of the magnitude of interference between the disc cutter ring and the body. The three-dimensional software SOLIDWORKS and the finite element software ANSYS is used to build mathematical model. And the aim was to optimize the magnitude design of interference between the disc cutter ring and its body, when the disc cutter cutting granite stratum. We analyzed the stress-strain of disc cutter ring and transmission torque on contact surface, finally obtained the optimal magnitude of interference (0.05mm). It could be verified with site operation. Therefore, in order to adapt the different geological condition, the finite element method provided theoretical basis for determining the optimal magnitude of interference between the disc cutter ring and the body.

The cables in the inner of equipments will also be damaged by high power EMP, because the electromagnetic energy can couple into the inner structure through slots in the shell of equipments. The electromagnetic effects on the thin line in a cubic cavity with a rectangle slot are simulated using thin line FDTD algorithm. The little slot is divided into many thin grids, and the transitional area is divided using sub-gridding technique. The influence of different length, different directions and different location in the cavity of the thin line on electromagnetic effects is studied. Some useful results are gotten.

High power electromagnetic pulse (EMP) can easily couple into the inner of targets via lots of slots. To calculate the EMP coupling effects on a cylinder object with openings, the coupling course is simulated using FDTD method in this paper. Gauss pulse and double exponential pulse are selected as the incident pulse source. The coupling EM field strength E inside the object and the current density J on the surface are calculated. Several rules about EMP coupling effects are gotten both in time and frequency domain. The results can help us to understand the damage effects of high power EMP.

Smart grid is a hot topic about the future development trend of power grid in recent years, as an important component of smart grid, smart automatic voltage control (AVC) has been given more and more attention. This paper starts with the construction ideas of smart grid, put forward the concept of Smart AVC, and by comparing the Smart AVC system and traditional AVC system, from the building background, technical features, construction process and benefit analysis etc sides described the design concept of Smart AVC.

The high power electromagnetic pulse (EMP) with sufficient radiating energy can penetrate and interfere on all kinds of radars. This paper studies the interference effect of high power EMP on paraboloid radar and AESA radar respectively. The coupling EMP (5us duration) energy via main lobe and side lobe into a paraboloid radar antenna is calculated. The distance and other parameters at which the sensitive component in radar front end can be damaged are presented. The coupling probability of EMP (single pulse and pulse trains) into the radar antenna in scanning state via main lobe or side lobe is studied and modeled. Finally, high power EMP hazard on the AESA radar is investigated, and some results about the needed values for 10 percent of T/R units destruction are presented.

Currently, damage effect of high power microwave (HPM) on electronic equipments is of increasing interest. HPM can disturb, damage, or destroy many military or civil electronic equipments. In this paper, the representative HPM waveform is investigated in time and frequency field respectively, and the main characteristics (peak power, rise time, power density, etc) are analyzed and listed. HPM generation devices and radiation are also discussed. Coupling energy into electronic devices via front door and back door, as a function of coupling coefficient and the effective area, is modeled. By presenting lots of kinds of coupling modes and paths, damage effects are divided into five different classes, and damage mechanism of HPM on electronic equipments is proven in the paper.

BACKGROUND Pim-1 plays an important role in the apoptosis, proliferation, differentiation of cancer cells and progression of cancer. In this study we detected the expression of pim-1 mRNA in normal prostate, benign prostatic hyperplasia (BPH), and prostate cancer (PCa) and explored its diagnostic value for PCa. METHODS The prostate tissues were collected from 23 patients with PCa, 37 patients with BPH, and 3 healthy volunteers. Pim-1 mRNA expression levels in these samples were determined by the quantitative real-time PCR (QRT-PCR). The differences of expression were calculated based on a standard curve. RESULTS The ratio of pim-1 mRNA to beta-actin in the normal prostate, BPH, and PCa were 1.05 +/- 0.04, 2.57 +/- 0.74 and 4.45 +/-0.63, respectively. The differences among PCa, BPH and NT were significant (P < 0.05, respectively). CONCLUSION Detecting pim-1 mRNA expression by QRT-PCR provides a reliable metric for the diagnosis of PCa.

With the continuous improvement of reliability requirements, studying the power switches' characteristics is of great significance in high-power electrical device. This paper presents a unified switching model suitable for the simulation of switching process with many kinds of switches in a large class of voltage sourced converter (VSC) systems. The model has many advantages such as simulating many switching dynamics states synchronously with less calculation, high simulation speed and easy parameter extraction from datasheets or measured waveforms. The model is also useful in selecting power switches, designing RCD snubbers, evaluating power loss, determining dead time and etc. The accuracy of the model is validated by comparing the experimental results with simulation ones for an IGCT-based VSC and an IGBT-based VSC.

The voltage-balancing problem of flying-capacitor inverter limits its application. A novel PWM control method is proposed, which has no limitation of voltage levels and can also keep the devices' switching frequencies near to each other. Simulations and experimental results are demonstrated to show its validity using a 5-level flying-capacitor inverter.

In this paper, a three level high voltage VSI (voltage source inverter) adjustable speed IM (induction motor) drive system with IGCTs (integrated gate commutated thyristors) is developed. Two IGCTs are in series connection in each cell of the inverter in order to obtain a 6 kV high voltage output. The DSP (data signal processor) with FPGA (field programming gate array) controller is adopted to fulfill an optimized constant V/Hz control strategy. SHE-PWM (selective harmonic eliminated)-(pulse width modulation) method is carried out to keep sine wave output.

IGCTs (integrated gate commutated thyristors) was developed by ABB to be widely used in high voltage converters. IGCT also has been adopted in series to get higher output voltage of the converters. In this paper, failure analysis of IGCTs in series connection in three level VSI (voltage source inverter) was put forward, we share our experience, and discuss how to make full use of IGCTs.

The operation monitoring and fault diagnosis system (OMFDS) for a /spl plusmn/20 Mvar STATCOM installation is thoroughly discussed in this paper. Several reasons necessitate developing such a system. After investigating the unique position of the OMFDS presented in the whole installation, the paper studies its hardware and software architecture and various functions. Practical tests verify the validity of the OMFDS and its effect to improve the performance of the STATCOM installation.

This paper presents the architecture of a digital signal processor (DSP) based control system for the first /spl plusmn/20 MVAr STATCOM in China. The control system includes the pulse generation and distribution unit for driving the GTO-based inverters and the central control unit. Both the units are based on DSP of TMS320C31. This paper gives the details of hardware and software development of the control system which was successfully applied to the first /spl plusmn/20 MVAr STATCOM in China in March, 1999. The field test results are also reported to verify the effectiveness of the control system in this paper.

A fuzzy ART neural network model based on the closeness theory, called CBFART, is introduced in this paper. It incorporates two concepts of the fuzzy set theory, the closeness and closet principle with the adaptive resonance theory (ART), to form a new neural network model. The model is characterized with a matching-consigning cycle, and classification of patterns in the network is followed by the closest principle. The complement coding, matching consigning, and fast learning-slow re-coding procedure work together to make sure that the learning of the network is converging and stable. The above three elements also make one shot learning to be practicable, so as to improve the learning speed of the network. The concrete algorithm of the model and the result of simulation are given, and an analysis shows that the model has a well clustering performance.

Static synchronous compensator (STATCOM) has been proved to have a number of advantages over other techniques available at present in stabilizing power transmission systems. To improve the stability of the power transmission system of China's Henan province, the Henan Electric Power Company and Tsinghua University have jointly investigated and developed a 20 MVA STATCOM employing GTO inverters. The STATCOM consists of four six-pulse voltage source inverters (VSIs) unit rated 5 MVA which use 48 GTOs rated 4500 V, 4000 A. The STATCOM has been installed in a 220 kV substation and has been put into operation successfully since April 1999. The field tests have been carried out to verify the performance and the long-term reliability of the installation. The outline, technical features and field test results of the 20 MVA STATCOM are given in this paper.

In order to enhance the operating reliability of ASVG (advanced static VAr generator), the "driving pulses blocking operation mode" is put into use which means that when blocking the conduction of switching components (GTO), the main switch connecting the ASVG to the power system keeps closed. For the configuration of large capacity ASVG based on multiple inverters, the mechanism of overvoltage on the DC side under driving pulses blocking operation mode is researched. With the help of a large amount of field tests and principal analysis, it is illustrated that overvoltage is caused mainly by the harmonic voltages on no-load transformers. The harmonic voltages are a result of harmonic magnetic flux caused by magnetic saturation of the transformer and complicated magnetizing circuit required by harmonic voltage elimination strategy. On the basis of mechanism research and circuit calculation, a simple countermeasure of suppressing overvoltage on the DC side is put forward. "Driving pulses blocking operation" is successful on a 300 kVAr ASVG.

With the development of Chinese industrial technique, electronic products tend to be small sized and portable. So it required batteries to be miniature, light weight, with high energy capacity and long service life. China had achieved great progress in electrochemical power sources industry in the last ten years. Especially, there is an ceaseless developing trend in the rechargeable battery field. Chinese chemical power source investigators had done a great deal of work on lead-acid, nickel-iron, nickel-cadmium (Ni-Cd), nickel-metal hydride (Ni-MH) and lithium ion batteries, among which, lead-acid, nickel-iron, nickel-cadmium and nickel-metal hydride batteries are produced in commercial scale. And some hopeful results were also achieved on rechargeable lithium batteries and lithium ion batteries. In this article we concentrate on the introduction of the research, development and manufacture status of nickel-cadmium and nickel-metal hydride batteries, hoping that this paper will give a deeper understanding in the field of Chinese rechargeable batteries.