The world's major textile powers: Special advantages and a new chapter in trade

Several countries have become notable production powers in the global textile market due to their unique advantages and strengths.In 2023,these countries not only occupied a leading position in terms of textile production scale,but also showed their unique charm in terms of technological innovation,market layout and foreign trade strategy.By thoroughly understanding the characteristics and advantages of the textile industry in these countries,as well as their performance in foreign trade,we can better grasp the development trends and opportunities of the global textile market.We look forward to these countries continuing to play a leading role in the global textile market and writing a new brilliant chapter.

基于Powershap特征选择的电力系统暂态稳定评估

为进一步提高暂态稳定评估(transient stability assessment,TSA)的精准度和可靠性,提出一种基于统计学与Shapley值结合的特征选择方法(Powershap),并建立电力系统TSA模型。首先,根据电力系统运行时的稳态分量构建输入特征集,采用Powershap将数据集分为多个数据子集进行训练,筛选出关键特征集;其次,利用关键特征集训练多个CatBoost模型并进行TSA,生成TSA模型;最后,在新英格兰10机39节点系统和加入新能源发电的新英格兰54机118节点系统上进行仿真实验,并给出评估结果。实验得出:在新英格兰10机39节点系统中采用基于Powershap特征选择的方法进行分类,其准确率能够达到99.79%;在改进的新英格兰54机118节点系统上,其准确率能够达到99.49%,说明该方法能够有效进行电力系统暂态稳定评估,并且验证了所提TSA模型具有较好的鲁棒性与泛化能力。

Preparation technology of ultra-fine powders of Auricularia auricular

Conventional mechanical method and mechanical method combined with vacuum freeze-drying technology were used to make the ultra-fine powders of edible fungus (Auricularia auricular). The content of basic nutrients, amino acid, micro structure and their properties of raw edible fungus and the edible fungus powders obtained with the two methods were analyzed and compared. The granularity size and micro-structure of the pulverized samples were analyzed by SEM and TEM technology. The average granularity size of the edible fungus powder obtained with mechanical method was 1–5 μm, while that obtained with mechanical method combined with vacuum freeze-drying process was 0.5–1 μm. The ultra-fine powders of edible fungus obtained with the two methods had better water recovery capability and quality, and their preserving time was longer than that of raw edible fungus. All the properties of the ultra-fine powders of edible fungus obtained with the vacuum freeze-drying technology were evidently superior to that of the conventional mechanical method. Keywords Auricularia auricula - Edible fungus - Ultra-fine powders - Vacuum freeze-drying CLC number TS205 Document code B Biography: YANG Chun-yu (1975), female, Ph. D. in Engineering Technology Center of Forestry and Wood Workine, Machinery, Northeast Forestry University, Harbin 150040, P. R. China.Responsible editor: Zhu Hong

Preparation of ultra-fine grain Ni-Al-WC coating with interlocking bonding on austenitic stainless steel by laser clad and friction stir processing

The ultra-fine structured Ni?Al?WC layer with interlocking bonding was fabricated on austenitic stainless steel by combination of laser clad and friction stir processing (FSP). Laser was initially applied to Ni?Al elemental powder preplaced on the austenitic stainless steel substrate to produce a coating for further processing. The as-received coating was subjected to FSP treatment, processed by a rotary tool rod made of WC?Co alloy, to obtain sample for inspection. Microstructure, phase constitutions, hardness and wear property were investigated by methods of scanning electronic microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDX) microanalysis, and X-ray diffraction (XRD), hardness test alongside with dry sliding wear test. The results show that the severe deformation effect exerted on the specimen resulted in an ultra-fine grain layer of about 100μmin thickness and grain size of 1?2μm. Synergy between introduction of WC particles to the deformation layer and deformation strengthening contributes greatly to the increase in hardness and friction resistance. An interlocking bonding between the coating and matrix which significantly improves bonding strength was formed due to the severe deformation effect.

Evaluation of ultra-fine grained tungsten under transient high heat flux by high-intensity pulsed ion beam

Pure tungsten, oxide dispersion strengthened tungsten and carbide dispersion strengthened tungsten were fabricated by high-energy ball milling and spark plasma sintering process. In order to evaluate the properties of the tungsten alloys under transient high heat flues, four tungsten samples with different grain sizes were tested by high-intensity pulsed ion beam with a heat flux as high as 160 MW/（m^2·s^-1/2）. Compared with the commercial tungsten, the surface modification of the oxide dispersion strengthened tungsten by high-intensity pulsed ion beam is completely different. The oxide dispersion strengthened tungsten shows inferior thermal shock response due to the low melting point second phase of Ti and Y2O3, which results in the surface melting, boiling bubbles and cracking. While the carbide dispersion strengthened tungsten shows better thermal shock response than the commercial tungsten.

利用PowerSATELITE进行广义无功功率测量与分析

介绍了一种新型电能计测终端Power SATELITE(saving assist tool of energy loggering intelligent terminal)。在非正弦波形下利用该仪器进行广义无功功率测量,并与传统功率仪器测量值进行比较,最后总结了两者值差的一般规律。

基于Powersystem模块的直流调速系统仿真研究

以控制系统的传递函数为基础,使用MATLAB Powersystem工具箱,对转速、电流双闭环直流调速系统进行了仿真,仿真结果表明采用该模块能够更接近调速控制系统实际性能指标。

T．C．POWERS若干重要理论评述

本文就所收集到的文献对Ｐｏｗｅｒｓ部分理论进行了简要评述，以期正确认识和运用Ｐｏｗｅｒｓ理论。

基于Matlab/SimPowerSystems的电力电子研究型实验

利用Matlab仿真技术拓展了电力电子实验的深度和广度,为其注入更多的研究性因素。首先搭建Matlab/SimPowerSystems仿真模型加以求解,引导学生对仿真结果进行理论分析和定量推导,启发学生对非预期的实验现象进行思考和讨论,给出定性解释。通过研究型实验的系统化训练,激发学生探索的精神、自主学习的能力、观察和研究的科研素养,教学质量显著提升。

基于SimPowerSystems的电力系统仿真与潮流分析

叙述了用MATLAB软件中的SIMULINK以及SimPowerSystems工具箱进行简单电力系统仿真的基本过程,并利用Powergui对相应系统进行动态仿真和系统潮流分析.对位于不同节点类型处的负荷模型仿真系统进行了讨论,并给出了模型的实现方法.

ICU患者置入Power PICC导管特殊异位原因分析

目的:探讨ICU患者置入Power PICC导管后头端反折向上至同侧和对侧锁骨下静脉、头臂静脉等特殊异位的相关因素。方法:回顾性分析2021年9月至2022年9月某三甲医院ICU 520例PICC置管患者,通过胸部X线确定PICC导管头端反折向上至对侧和同侧锁骨下静脉、头臂静脉的患者,分析其特殊异位发生因素。结果:胸部X线结果显示25例患者PICC管头端反折向上异位至对侧和同侧锁骨下静脉、头臂静脉或颈内静脉,异位发生率4.8%,不同静脉置管反折异位发生率相比差异无统计学意义,P>0.05。结论:ICU患者PICC置入发生导管头端反折向上至同侧和对侧锁骨下静脉、头臂静脉等特殊异位的发生因素较多,包括同时留置CVC或血透管、正在滴注或泵入多种药物、PICC管头端异位的隐匿性、导管材质、自身疾病及机械通气等危险因素。

基于SimPowerSystems的电力系统仿真实践教学研究

对电力系统仿真实践教学进行了研究,重点对基于SimPowerSystems工具的电力系统仿真过程进行了详细论述,首先介绍了电力系统仿真各部件模型,接着详细论述了基于SimPowerSystems的电力系统仿真模型建立过程,包括具体步骤和相关指标,最后通过某地区实际电力系统仿真模型的建立和运行分析,说明通过SimPowerSystems进行电力系统仿真实践教学和研究是十分有效的途径.

Influence of ultra-fine fly ash on hydration shrinkage of cement paste

Hydration shrinkage generated by cement hydration is the cause of autogenous shrinkage of high strength concrete. It may result in the volume change and even cracking of mortar and concrete. According to the data analysis in a series of experimental studies, the influence of ultra-fine fly ash on the hydration shrinkage of composite cementitious materials was investigated. It is found that ultra-fine fly ash can reduce the hydration shrinkage of cement paste effectively, and the more the ultra-fine fly ash, the less the hydration shrinkage. Compared with cement paste without the ultra-fine fly ash, the shrinkage ratio of cement paste reduces from 23.4% to 39.7% when the ultra-fine fly ash replaces cement from 20% to 50%. Moreover, the microscopic mechanism of the ultra-fine fly ash restraining the hydration shrinkage was also studied by scanning electron microscopy, X-ray diffraction and hydrated equations. The results show that the hydration shrinkage can be restrained to a certain degree because the ultra-fine fly ash does not participate in the hydration at the early stage and the secondary hydration products are different at the later stage.

Optimal Conditions for Preparing Ultra-Fine CeO_2 Powders in A Submerged Circulative Impinging Stream Reactor

Cerium carbonate powders were produced in a submerged circulation impinging stream reactor （SCISR） from Ce（NO3）3· 6H2O. NH4HCO3 was used as a precipitant in the reaction. Cerium carbonate powders were roasted to produce ultra-fine cerium dioxide （CeO2） powders. The optimal conditions of such production process were obtained by orthogonal and one-factor experiments. The results showed that ultra-fine and narrowly distributed cerium carbonate powders were produced under the optimal flowing conditions. The concentrations of Ce（NO3）3 and NH4HCO3 solutions were 02,5 and 0.3 mol · L^-1, respectively. The concentration of PEG4000 added in these two solutions was 4 g · L^-1. The stirring ratio, reaction temperature, feeding time, solution pH, reaction time and digestion time were 900 r · min^- 1,80 ℃, 20 min, 5 - 6, 5 min and 1 h, respectively. The final product, CeO2 powders, was obtained by roasting the produced cerium carbonate in air for 3 h at 500 ℃. The finally produced CeO2 powders were torispherical particles with a narrow size distribution of 0.8 -2.5 μm. The crystal structure of CeO2 powders belonged to cubic crystal system and its space point 5 group was OH^5-FM3M. Under optimal conditions, powders produced by SCISR were finer and more narrowly distributed than that by Stirred Tank Reactor （STR）.

Microstructures of ultra-fine grained FeCoV alloys processed by ECAP plus cold rolling and their evolutions during tempering

A new processing method,equal channel angular pressing(ECAP)plus cold rolling(CR),was applied to producing ultra-fine grained FeCoV alloy.The microstructures of ultra-fine grained FeCoV alloy after ECAP,ECAP plus CR,and the effect of tempering treatment on the microstructure of FeCoV alloy produced by ECAP plus CR were investigated.The results show that an elongated substructure with a width of about 0.3μm is obtained after four-pass ECAP using Route A.Cold rolling after ECAP cannot change the morphologies of elongated substructure,and it results in higher fraction of high-angle boundaries and higher dislocation density compared with the identical ECAP without rolling.Subsequent tempering for 30 min at 853 K brings about many nano-phases precipitating at subgrain boundaries and insides the grains,and the size of precipitated phase is measured to be about 10 nm.Nano-phases grow up with increasing tempering temperature and equiaxed structure forms at 883 K.

DYNAMIC RHEOLOGICAL BEHAVIOR OF POLYPROPYLENE FILLED WITH ULTRA-FINE POWDERED RUBBER PARTICLES

Dynamic rheological characteristics of polypropylene (PP) filled with ultra-fine full-vulcanized powdered rubber (UFPR) composed of styrene-butadiene copolymer were studied through dynamic rheological measurements on an Advanced Rheometric Expansion System (ARES). A specific viscoelastic phenomenon, i.e. 'the second plateau', appeared at low frequencies, and exhibits a certain dependence on the amount of rubber particles and the dispersion state in the matrix. This phenomenon is attributed to the formation of aggregation structure of rubber particles. The analyses of Cole-Cole diagrams of the dynamic viscoelastic functions suggest that the heterogeneity of the composites is enhanced on increasing both particle content and temperature.

Improving the Fatigue Performance of the Welded Joints of Ultra-Fine Grain Steel by Ultrasonic Peening

Contrast tests were carried out to study the fatigue performance of the butt joints treated by ultrasonic peening, aiming at the improvement of ultrasonic peening treatment(UPT) on welded joints of a new material. The material is a new generation of fine grain and high purity SS400 steel that has the same ingredients as the traditional low carbon steel. The specimens are in two different states:welded and ultrasonic peening conditions. The corresponding fatigue testing data were analyzed according to the regulation of the statistical method for fatigue life of the welded joints established by International Institute of Welding(IIW). Welding residual stress was considered in two different ways: the constant stress ratio R=0.5 and the Ohta method. The nominal stress-number (σ-N)curves were corrected because of the different plate thickness compared to the standard and because there was no mismatch or angular deformation. The results indicated that: 1) Compared with the welded specimens, when the stress range was 200 MPa, the fatigue life of the SS400 steel specimens treated by ultrasonic peening is prolonged by over 58 times, and the fatigue strength FAT corresponding to 106 cycles is increased by about 66%; 2) As for the SS400 butt joint (single side welding double sides molding), after being treated by UPT, the nominal S-N curve (m=10) of FAT 100 MPa(R=0.5) should be used for fatigue design. The standard S-N curves of FAT 100 MPa(R=0.5, m=10) could be used for fatigue design of the SS400 steel butt joints treated by ultrasonic peening.

Isothermal Growth Kinetics of Ultra-fine Austenite Grains in a Nb-V-Ti Microalloyed Steel

Ultra-fine austenite grains with size of i-3 μm were prepared in a Nb-V-Ti steel through repetitive treatment of rapid heating and quenching. A model for the growth kinetics of these ultra-fine austenite grains was successfully created through successive 2 processes, and the activation energy Q for growth was estimated to be about 693.2 kJ/mol, which directly shows the inhibition effect of microalloy elements on the growth of ultra-fine austenite grains.

Weld formation and heating mechanism in ultra-narrow gap withconstricted arc by ultra-fine granular flux

Ultra-narrow gap welding （UNGW） process with high stabilization, reliability and without spatter can be achieved with constricted arc by molten slag wall, which is made from melted flux. The experiments are carried out by changing voltage under different currents. The results indicate voltage range being fit for UNGW is about 22 -31 V under the current range of 200 -320 A. With the increasing of voltage, weld formation of UNGW has the law of lack of fusion on sidewall, good weld and undercut in turn under a certain current. In addition, the action relationships among arc, molten slag wall and sidewalls can be improved by properly adjusting voltage and current of arc, which makes cathode spot properly distribute in ultra-narrow gap. Therefore, the effective control of weld formation of UNGW has been achieved.

Approach to the Geopolitical Influences of Great Powers in Southeast Asia: Case Studies of China and the US

A quantitative approach to the national geopolitical influence is helpful to provide a reference for national sustainable development on the international stage, based on describing national diplomatic capacity and overseas influence. Herein, this study proposes a complex geopolitical influence model, considering the affected nations' response. The geopolitical influences of great power in the affected nation are correlated with overall strength, the acceptance degree of the affected nation to the great power and the distance between both sides. Then, the geopolitical influences of China and the US in Southeast Asia countries are empirically analyzed from 2005 to 2015. The geopolitical influence of China in Southeast Asia has been largely growing for the past decades, accompanying with a constant trend of the US' effects. It is believed that China and the US can coexist peacefully in Southeast Asia to promote the regional development, and jointly create an open, inclusive and balanced regional cooperation architecture that benefits all nations in this region and great powers, through mutual political trust and economic beneficial cooperation. This study may contribute to advancing the policy debate and determining the optimal cooperation in pledging commitment to a new and sustainable model of great power relationship among the various regional geopolitical options.