High-power piezoelectric energy harvester produced using [0 0 1]-textured (Na,K)NbO3-based lead-free piezoceramics

High-power piezoelectric energy harvesters (PEHs) require piezoceramics with a large k_p and d₃₃ but small ε^T₃₃/ε₀ values. The [0 0 1]-textured 0.96(Na, K)(Nb_1−xSb_x)–0.04SrZrO₃ piezoceramics (x = 0.025 and 0.045) exhibited the improved electromechanical coupling factor (k_p) and piezoelectric charge constant (d₃₃); however, the increase of dielectric constant (ε^T₃₃/ε₀) was not significant. Further, the textured piezoceramic with x = 0.045 shows the large d₃₃ × g₃₃ value of 21.5 pm²/N, where g₃₃ is piezoelectric voltage constant, indicating that texturing is a good technique to fabricate the piezoceramics for PEH. The impedance curve of the PEH consisting of the metal substrate and textured piezoceramic shows a piezoelectric resonance peak at a low frequency, which is the same as the mechanical resonance frequency of the PEH. Hence, the PEH can be considered a piezoelectric material. The figure of merit of the PEH was determined using the mechanical quality and electromechanical coupling factor calculated from the impedance curve of the PEH. A large power output of 1.7 mW was obtained from the type-1 PEH at the resonance frequency produced using the textured thick film (x = 0.045). Hence, this PEH can be used as a permanent power source for microelectronic devices in the Internet of Things.     

Heat of absorption of CO2 in aqueous N,N-diethylethanolamine + N-methyl-1,3-propanediamine solutions at 313 K

Differential heat of absorption of CO_2 in aqueous solutions of N,N-diethylethanolamine(DEEA) and activated DEEA solutions up to a total concentration of 2 mol·L~(-1) was measured as a function of CO_2 loading at 313.15 K using a reaction calorimeter. In order to analyze the performance of N-methyl-1,3-propanediamine(MAPA)as an activator, DEEA blended solutions containing 0.05, 0.1 and 0.2 mol·L~(-1) MAPA were studied. The heat of CO_2 absorption in single DEEA solutions was unaffected by changing the DEEA concentration in the range of(0.5–2) mol·L~(-1). On the other hand, increasing the concentration of MAPA in aqueous amine mixtures of(DEEA + MAPA) raised the heat of absorption.     

In-situ elongated aluminium borate grains toughening WC- 1.87 wt % Al2O3- 4.13 wt % ZrO2 composite via spark plasma sintering

In this work, a novel way was developed to facilitate the sintering of a binderless cemented carbide with Al₂O₃ contain while improving its toughness. WC- 1.87 wt % Al₂O₃- 4.13 wt %ZrO₂ cemented carbides with 1 wt % B₂O₃ as additives were consolidated by high energy ball-milling and spark plasma sintering the as-milled composite powders. The effects of 1 wt % B₂O₃ content on the sintering behaviour, microstructure and mechanical properties of the obtained cemented carbides were investigated. The presence of B₂O₃ significantly lowers the sintering temperature by forming liquid phase and react with Al₂O₃ which contributed to obtaining fully dense specimens at 1350 °C and maintains fine grain sizes of WC until the temperature exceeding 1450 °C. The sintering temperature of the specimens with optimum mechanical properties has been also reduced comparing that of the original WC- 1.87 wt % Al₂O₃- 4.13 wt %ZrO₂ cemented carbides. Furthermore, the addition of B₂O₃ triggered the reaction between B₂O₃ and Al₂O₃ resulting in forming in-situ elongated aluminium borate grains (A₄B₂O₉ and A₁₈B₄O₃₃ whiskers), which promoted the toughness. The specimens sintered at 1450 °C exhibited optimal mechanical properties: the Vickers hardness and fracture toughness were 19.26 GPa and 11.49 MPa m^1/2, respectively.     

洛阳传顺机械设备有限公司 公司专营申克K40、K50/K80、K120/K180煤粉计量秤

★气密封测量轮轴系总成★测量齿轮箱总成的大、中、小修理,配件加工及总成加工、制作业务。公司产品所用轴承、密封、传感器全部采用原装进口,以稳定的性能、质量和快速、     

K展预览

全球规模最大的塑料橡胶工业展览会-K展．将于今年10月20∽27日在德国杜塞尔多夫举行,这届盛会是第16届。今年的展馆总面积比2001年的K塑展扩大了约6％．超过16万m^2。机器制造商和辅助仪器设备生产供应商将把今年增扩的面积全部包租下来,他们的展位面积占总面积的2／3。以下重点介绍K2004展会上的新亮点：     

锐鹰K8

闪光灯雷达罩用来发散光源，使光的对比度更加和谐。雷达罩可以将闪光灯的投射范围变得更宽，一般可以配合跳灯反射同时使用。     

K展新动态

世界规模最大的塑料和橡胶展览会,K2001,于10月25日至11月1日在德国的杜塞尔多夫举行。今年的K展览会的一个主要趋势是,欧洲注塑机制造商提供全电动设备的厂商数目有日益增加的迹象。 亚洲明显超过欧洲,是最大的全电动注塑机制造地区,同时也是最大的使用地区,而其中以日本为主。欧洲正在后起直追。     

K+/Cl-,Br- -H2O三元体系298 K,313 K,333 K时的相平衡

用等温溶解平衡法测定了三元体系 K /Cl-,Br--H2O 298 K、313 K、333 K时的相平衡数据,同时还测定了饱和溶液的密度、折光率等物化性质,依据湿渣法与X射线衍射相结合的方法对平衡固相组成进行了鉴定.该三元体系 298 K、313 K、333 K的溶解度等温图有 1 个固相区:K(Cl,Br),有 1 条单变量曲线,该体系属于固体溶液型.用Pitzer模型计算测得的三元体系 298 K、313 K、333 K溶解度,并用经验公式对平衡液相的密度、折光率进行了计算,计算值与实验值基本吻合.     

298K、303K及308K下纳米腐植酸在尿素水溶液中的相平衡

生产纳米腐植酸增值尿素过程中,纳米腐植酸在尿素水溶液中溶解度数据尤为重要。采用等温溶解平衡法研究了纳米腐植酸在298、303及308 K尿素水溶液中溶解度及密度数据;按照相平衡数据绘制相应的相图。湿渣法和X-射线粉末衍射法(XRD)相结合方法对平衡固相组成鉴定。实验结果表明:该三元固液相体系相图存在4个相区,分别为纳米腐植酸及尿素纯固相结晶区,纳米腐植酸与尿素共结晶区和未饱和液相区,1个共饱和点,且该体系为简单共饱和型,无固溶体形成。该三元体系308 K与298 K、303 K相图相比,308 K时未饱和液相区增大,纳米腐植酸-尿素共结晶区减小。298、303和308 K下,其相应共饱和点处密度最大值分别为1.2145、1.2333及1.2502 g?cm?3。     

K.K苯加氢系统萃取精馏单元的模拟

应用AspenPlus流程模拟软件,建立了K.K苯加氢系统萃取精馏单元的计算模型。对宝钢K.K苯加氢装置的操作工况进行了模拟计算,并利用模型对生产装置进行了分析。模拟结果与生产数据相吻合,表明所建立的模型能够用于工程设计和指导生产。     

减少涤纶低弹丝K丝及半K丝的方法

本文讨论了实际生产中Ｋ丝的形成及其解决方法，通过这些方法，有效地减少了Ｋ比的产生。提高了成品丝的染色性能，从而提高了产品质量。     

去K展观新潮

随着10月底的到来,世界各国塑料行业的人士就将陆续启程,赴德国参加2010年的K展。作为全球塑料及橡胶行业展览盛事中的旗舰．几十年来．K展总是以其对各种最创新塑料及橡胶技术的集中展示,引发了人们的极大关注和热情．人们期待着在此了解行业发展的风向,获取更多最新潮的理念。那么,2010年的K展又将带来哪些新的潮流呢？     

K 2004展会综览

2004年10月27日．K2004国际塑料橡胶展览会于德国杜塞尔多夫展览中心成功闭幕．这是每3年举办一届的全球第一的塑料及橡胶技术展览会,在提供商机、展示创新技术和预览行业发展趋势方面已经有50多年的历史。K2004展览会规模空前．有来自50多个国家和地区的参展商展出了各种塑料机械、产品和提供技术服务．展区主要分为原料和辅助材料、半成品、技术部件和强化塑料、机械和设备、     

Enhancing 1.8 μm emission from ultra-broadband Tm-Bi-Er tri-doped fluorotellurite glasses for fiber amplifiers and near-infrared lasers

Fluorotellurite glasses tri-doped with Tm³⁺, Er³⁺ and Bi ions were investigated. The measured parameter ΔT (116 °C) confirmed that the prepared glasses had good stability. An ultra-broadband fluorescence emission (950–1670 nm) was observed with a full-width at half-maximum (FWHM) of 560 nm, which covered the entire bands of O, E, S, C, L and U. The 1800 nm fluorescence intensity of Tm³⁺/Er³⁺ co-doped and Tm³⁺/Er³⁺/Bi tri-doped glasses was enhanced compared to Tm³⁺ doped glass, which indicates that there is energy transfer between Tm³⁺, Er³⁺ and Bi ions. The maximum fluorescence lifetime of the prepared glasses was 7.39 ms, indicating the excellent fluorescence performance at 1800 nm. Additionally, the maximum absorption cross section (σ_abs = 1.77 × 10⁻²⁰ cm⁻²) and emission cross section (σ_em = 7.61 × 10⁻²⁰ cm⁻²) suggest that the Tm³⁺/Er³⁺/Bi tri-doped glasses have good optical absorption properties and high gain fluorescence emission. The above results indicate that the Tm³⁺/Er³⁺/Bi tri-doped fluorotellurite glasses have good application prospects in the field of fiber amplifiers and near-infrared lasers.     

宝钢Litol法与K.K法粗苯加氢的对比

本文介绍了宝钢2套粗苯加氢装置的生产状况,并对Litol法与K.K粗苯加氢的原理、工艺流程、生产费用、产品质量等方面进行了分析对比,综合生产中的各项数据,我们认为K.K法粗苯加氢精制应作为我国焦化企业的首选方法。     

THERMAL CONDUCTIVITY OF THF CLATHRATE HYDRATE FROM 243 K TO 263 K

Using transient plane source technique, we measured THF hydrate thermal conductivity from 243 K to 263 K. The sample THF solution is over saturated in order to avoid the effect of ice. And also to avoid the effect of crystal anisotropy, the THF hydrate was crushed to measure. In the test temperature range of the experiment, the THF hydrate has a thermal conductivity about 0.45W·m~(-1)·K~(-1), and the value increases with the temperature increasing.     

三元乙丙橡胶K6470C与K778Z性能对比研究

正随着聚烯烃弹性体技术的发展,三元乙丙橡胶的生产技术已经从单一的齐格勒—纳塔(Ziegler-Natta)催化体系及其相应的溶液聚合工艺发展到ZieglerNatta系—茂金属系—单电催化等系列催化体系,及其相应的溶液聚合工艺,悬浮聚合工艺和气相聚合工艺组成的多元化技术格局。2011年5月朗盛化学完成了对荷兰帝斯曼(DSM)公司三元乙丙橡胶业务的收购,并对全球4个生产工厂的产品进行整合,     

K480氧化氮压缩机故障处理及K500压缩机改造方案

0　前　言目前 ,用综合法生产硝酸的一些中氮厂所用氧化氮压缩机仍采用原苏联 5 0年代产的 K480氧化氮透平压缩机 (以下简称 K480压缩机 ) ,该机型在使用中常出现三大问题 :一是止推瓦易烧 ,据统计 ,因止推瓦烧坏或过量磨损引起的停机事故约占该机总故障的 80 % ;二是回收轮个别叶片断裂脱落使转子失去平衡 ,产生强烈振动引起停车 ;三是三四级叶轮、隔板导流器因腐蚀寿命缩短 ,机壳中分面因腐蚀引起密封失效而导致氧化氮外泄 ,污染操作环境。前苏联在 70年代推出的 K5 4 0氧化氮压缩机是 K480压缩机的换代产品 ,90年代初国产化后称之为 D…     

Fabrication of Er:Y2O3 transparent ceramics for 2.7 μm mid-infrared solid-state lasers

Laser grade 7 at.% Er:Y₂O₃ transparent ceramics with submicron grain size were fabricated by using one-step vacuum sintering followed by hot isostatic pressing (HIPing) technique. Through studying the sintering trajectory of Er:Y₂O₃ ceramics, the sintering temperature zone where sufficient relative density (>96%), no pore-boundary separation, and sub-micron grain size (<1 μm) ceramic samples could be identified. The samples pre-sintered in this zone were readily densified by HIPing. To maximum the densification and achieve high transparency, it is critical to suppress the final-stage grain growth. After HIPing at 1520 °C, the Er:Y₂O₃ ceramics were fully densified without further grain growth, and exhibited in-line transmission of about 81.6% at 2000 nm. Continuous wave (CW) room temperature laser operation of the Er:Y₂O₃ transparent ceramic at 2.7 μm was demonstrated.     

308.15 K、313.15 K和318.15K下4-氨基丁酸在硫酸沙丁胺醇水溶液中的体积和黏度研究

Density (&#61554;) and viscosity (η) measurements were carried out for 4-aminobutyric acid in 0.0041, 0.0125 and 0.0207 mol&#8226;L－1 aqueous salbutamol sulphate at 308.15, 313.15 and 318.15 K. The measured values of density and viscosity were used to estimate some important parameters such as apparent molar volume , limiting apparent molar volume , transfer volume , hydration number , second derivative of infinite dilution of partial molar volume with temperature , viscosity B-coefficients, variation of B with temperature dB/dT, free energy of activation per mole of solvent and solute , activation entropy and activation enthalpy of the amino acids. These parameters have been interpreted in terms of solute-solute and solute-solvent interactions and structure making/breaking ability of solutes in the given solution.