Preparation and Application of C60 High Performance Concrete

C60 High Performance Concrete (HPC) was prepared by limiting cement content and adopting compositesuperplasticizer, low-alkalinity expansive agent and high-quality line mixture. The results showed that the performance of the prepared C60 HPC was excellent. By adopting some advanced construction techniques such as usingsecondary vibration and secondary face compaction, controlling temperature difference and paying special attentionto early curing in the construction process, the prepared C60 HPC had been successfully applied in the monolithicstructure of huge building.

Recent Developments of Modulation and Control for High-Power Current-Source-Converters Fed Electric Machine Systems

The pulse-width-modulated(PWM)current-source converters(CSCs)fed electric machine systems can be considered as a type of high reliability energy conversion systems,since they work with the long-life DC-link inductor and offer high fault-tolerant capability for short-circuit faults.Besides,they provide motor friendly waveforms and four-quadrant operation ability.Therefore,they are suitable for high-power applications of fans,pumps,compressors and wind power generation.The purpose of this paper is to comprehensively review recent developments of key technologies on modulation and control of high-power(HP)PWM-CSC fed electric machines systems,including reduction of low-order current harmonics,suppression of inductor–capacitor(LC)resonance,mitigation of common-mode voltage(CMV)and control of modular PWM-CSC fed systems.In particular,recent work on the overlapping effects during commutation,LC resonance suppression under fault-tolerant operation and collaboration of modular PMW-CSCs are described.Both theoretical analysis and some results in simulations and experiments are presented.Finally,a brief discussion regarding the future trend of the HP CSC fed electric machines systems is presented.

High T_c Superconducting Materials for Strong Current Applications:Approach at the First Stage

Strong current and large-scale application is the most important prospect of high Te superconductors （HTS）. Practical HTS samples in various forms have been produced with high critical currents operated at economic cryogenic temperatures. Engineering applications of those HTS materials have been studied with various HTS prototype devices. The applicable HTS materials produced in different forms are verified in this paper with regard to their strong current characterizations, and the HTS applications are summarized along with the HTS prototypes made.

Summary of the First Generation High Temperature Superconducting Wire: Processing, Characterization and Applications

Silver-clad （Bi,Pb）2Sr2Ca2Cu3O10＋x long wires produced by powder-in-tube techniques, which have been recognized as the first generation of the High Temperature Superconducting （HTS） wires, are expected to apply widely especially in strong current applications. In this work, the processing, characterization and application of the silver-clad （Bi,Pb）2Sr2Ca2Cu3Ol0＋x HTS wires are summarized. The HTS wires are fabricated using the combination of powder-in-tube technique, and the resulting wires are fully characterized by the means of chemical analyses, microstructural observation, electrical and magnetic measurements. The relationship among fabrication parameters, chemical and microstructural characteristics, and electrical and magnetic properties are analyzed. Applications of the HTS wires have also been introduced according to their strong current behaviors with various prototype devices made.

AN SCF-CI STUDY OF HIGHLY EXCITED VIBRATIONAL STATES OF BENT TRIATOMIC MOLECULES AND ITS APPLICATION TO O_(3)

A self-consistent-field—configuration interaction(SCF-CI)procedure of studying highly excited vibrational states of bent triatomic molecules is suggested and its application to O_3 is investigated.

Thermal management by manipulating electromagnetic parameters

Electromagnetic absorbing materials may convert electromagnetic energy into heat energy and dissipate it.However,in a high-power electromagnetic radiation environment,the temperature of the absorbing material rises significantly and even burns.It becomes critical to ensure electromagnetic absorption performance while minimizing temperature rise.Here,we systematically study the coupling mechanism between the electromagnetic field and the temperature field when the absorbing material is irradiated by electromagnetic waves.We find out the influence of the constitutive parameters of the absorbing materials(including uniform and non-uniform)on the temperature distribution.Finally,through a smart design,we achieve better absorption and lower temperature simultaneously.The accuracy of the model is affirmed as simulation results aligned with theoretical analysis.This work provides a new avenue to control the temperature distribution of absorbing materials.

Fabrication and magnetic properties of NiFe-ZnO nano-granular films

Excellent soft magnetic and high frequency prop- erties were obtained successfully in the （Ni75Fe25）x（ZnO）1-x granular films fabricated on the glass substrate by RF magnetron oblique sputtering. The microstructure, mag- netic and high frequency properties were investigated systematically. High resolution transmission electron micrographs show that the film consists of fcc Ni75Fe25 particles uniformly embedded in an amorphous insulating matrix ZnO with particle size a few nanometers. The （Ni75Fe25）x（ZnO）1-x films exhibit excellent soft magnetic properties in a widex range from 0.50 to 0.80 with coer- civity not exceeding 5 × 10^-4 T, which is ascribed to the exchange coupling between magnetic particles. Especially for the sample with x = 0.64, coercivities in hard and easy axes are 5.0 ×10^-5 and 3.6 × 10^-4 T, respectively, and the electric resistivity ρ reaches 1,790 μΩ.cm. The dependence of complex permeability u = u′- ju″on frequency f shows that the real part u′ is more than 130 below 500 MHz, and the ferromagnetic resonance fre- quency fr reaches 1.32 GHz, implying the promising for high frequency application.

Estimating the Limits in System Design for 48 V Automotive Power Applications

The design process in power electronics is driven by increased utilisation level of the used components to gain performance whilst keeping cost low. This article provides an overview on challenges in low-voltage high-current systems, e.g. used in automotive applications. The main content points are： topology selection--single systems vs. cascaded systems, PCB manufacturing technology overview, current measurement methods, bulk capacitor design （ceramic DC link） and PCB design instructions for high-current systems. The PCB design instructions target on optimised thermal design for maximised PCB utilisation and on optimised track design for a low inductance DC link interconnection. The paper bases on calculations, measurements and simulations.

Analysis of cerium substitution in Co-Sr based spinel ferrites for high frequency application

Spinel ferrites exhibit exceptional magnetic properties,making them a distinctive class of magnetic materials.The sol-gel technique was utilized for the synthesis of spinel ferrites with the chemical formula Co_(0.6)Sr_(0.4)Ce_(x)Fe_(2-x)O_(4). Following that,a comprehensive X-ray diffraction analysis unveiled the crystalline cubic structure of the synthesized materials.Through the utilization of the M-H loop approach,the ferromagnetic attributes of ferrites were assessed,and the assimilation of rare earth elements led to substantial enhancements in saturation magnetization,remanence,and coercivity.Spinel ferrites with a high concentration of rare earth elements have improved direct current resistivity and activation energy.The logarithm of a material's resistance increased from 5.29 to 8.12 Ω·cm as cerium is added.With a change in the amount of cerium,the activation energy goes up from 0.19 to 0.29.By changing the frequency from 5.5 to 9.5 GHz,the dielectric characteristics were determined.As the frequency goes up,the dielectric constant goes down.Spinel ferrites that have been made better in every way can be used in high-frequency applications.

Guest editorial of "Application of high strength steels in lightweight commercial vehicles"

New and increasingly sharp laws for the reduction of emissions from commercial vehicles entered into force in the European Union since 1993 with the aim of substan-tially reducing pollutants and emissions from trucks and buses. Thereby the maximum levels for the emission of particulate matter （basically soot particles） as well as oxides of nitrogen （NOx） have been subsequently lowered. To comply with these demands, commercial vehicle producers had to introduce new emission reducing technologies of which exhaust-gas recirculation （EGR）,

MOCVD growth of AlGaInP/GaInP quantum well laser diode with asymmetric cladding structure for high power applications

In order to improve the characteristics of the general broad-waveguide 808-nm semiconductor laser diode （LD）, we design a new type quantum well LD with an asymmetric cladding structure. The structure is grown by metal organic chemical vapor deposition （MOCVD）. For the devices with 100-ttm-wide stripe and 1000-/zm-long cavity under continuous-wave （CW） operation condition, the typical threshold current is 190 mA, the slope efficiency is 1.31 W/A, the wall-plug efficiency reaches 63%, and the maximum output power reaches higher than 7 W. And the internal absorption value decreases to 1.5 cm^-1.

A hybrid biometric identification framework for high security applications

Research on biometrics for high security applica- tions has not attracted as much attention as civilian or foren- sic applications. Limited research and deficient analysis so far has led to a lack of general solutions and leaves this as a challenging issue. This work provides a systematic analy- sis and identification of the problems to be solved in order to meet the performance requirements for high security applica- tions, a double low problem. A hybrid ensemble framework is proposed to solve this problem. Setting an adequately high threshold for each matcher can guarantee a zero false accep- tance rate （FAR） and then use the hybrid ensemble framework makes the false reject rate （FRR） as low as possible. Three ex- periments are performed to verify the effectiveness and gener- alization of the framework. First, two fingerprint verification algorithms are fused. In this test only 10.55% of fingerprints are falsely rejected with zero false acceptance rate, this is sig- nificantly lower than other state of the art methods. Second, in face verification, the framework also results in a large re- duction in incorrect classification. Finally, assessing the per- formance of the framework on a combination of face and gait verification using a heterogeneous database show this frame- work can achieve both 0% false rejection and 0% false accep- tance simultaneously.

PST TiAl single crystals for high temperature applications

Recently,the research team led by Prof.Chen Guang(陈光)at the Engineering Research Center of Materials Behavior and Design,Ministry of Education,Nanjing University of Science and Technology,successfully manufactured a new kind of high-temperature polysynthetic twinned(PST)TiAl single

Wide gap active brazing of ceramic-to-metal-joints for high temperature applications

Applications like solid oxide fuel cells and sensors increasingly demand the possibility to braze ceramics to metals with a good resistance to high temperatures and oxidative atmospheres. Commonly used silver based active filler metals cannot fulfill these requirements, if application temperatures higher than 600℃ occur. Au and Pd based active fillers are too expensive for many fields of use. As one possible solution nickel based active fillers were developed. Due to the high brazing temperatures and the low ductility of nickel based filler metals, the modification of standard nickel based filler metals were necessary to meet the requirements of above mentioned applications. To reduce thermally induced stresses wide brazing gaps and the addition of A1203 and WC particles to the filler metal were applied. In this study, the microstructure of the brazed joints and the thermo-chemical reactions between filler metal, active elements and WC particles were analyzed to understand the mechanism of the so called wide gap active brazing process. With regard to the behavior in typical application oxidation and thermal cycle tests were conducted as well as tensile tests.

Tianjin CATARC Auto Hi-Tech Company and Tianjin Tianfeng Auto Hi-Tech Development Company --Development and Application of Auto High & New Technology

Tianiin CATARC Auto Hi-tech Company, approved by the State Planning and Developing Commission, is a manufacturing enterprise specialized in auto catalyst converters, which was listed in "The First Group Localization Projects for Environmental Protection Equipment in 1999". This company enjoys the perfect matching techniqueS for catalyst converter system, modern manufacturing shops and world-level labs. The annual production capacity is 300 thousand sets of catalyst converters in conformity with tile

Sandwich-type composite multilayer films of strontium titanate and barium strontium titanate and their controllable dielectric properties

It is a challenge to reduce the dielectric loss and increase the tunability of pure barium strontium titanate(BST)films for microwave tunable application because these two properties change simultaneously.Herein,a novel composite of strontium titanate(ST)and potassium-doped BST(KBST)has been designed as ST/KBST/ST sandwich-type film with various ST and KBST layers.X-ray diffraction patterns show that the film exhibits cubic perovskite polycrystalline structure composed of BST and ST phase,mainly grow along(110)crystal plane with average grain size of less than 20 nm and decreasing BST phase/ST phase ratio with increasing film thickness.Scanning electron microscope shows that no interfacial layer can be observed,indicating that ST and KBST are fully compounded.Low dielectric loss and high tunability at-10-10 V and stable and excellent dielectric properties at 1 GHz are achieved,meeting the needs of microwave tunable application at high frequency.The surface structures are also studied by other analysis methods,and ST/MgBST/ST sandwich-type film is compared.

Biomedical titanium alloys and their additive manufacturing

Titanium and its alloys have been widely used for biomedical applications due to their better biomechanical and biochemical compatibility than other metallic materials such as stainless steels and Co-based alloys.A brief review on the development of the b-type titanium alloys with high strength and low elastic modulus is given and the use of additive manufacturing technologies to produce porous titanium alloy parts,using Ti-6Al-4V as a reference,and its potential in fabricating biomedica replacements are discussed in this paper.