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MHD free convective flow past semi-infinite vertical permeable wall

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Applied Mathematics and Mechanics(English Edition) 2012年第9期33卷 1207-1222页

作者： R.k.SINGH A.k.SINGH Department of Mathematics Banaras Hindu University

In this paper, the basic equations governing the flow and heat transfer of an incompressible viscous and electrically conducting fluid past a semi-infinite vertical per- meable plate in the form of partial differential equations are reduced to a set of non-linear ordinary differential equations by applying a suitable similarity transformation. Approx- imate solutions of the transformed equations are obtained by employing the perturbation method for two cases, i.e., small and large values of the suction parameter. From the numerical evaluations of the solution, it can be seen that the velocity field at any point decreases as the values of the magnetic and suction parameters increase. The effect of the magnetic parameter is to increase the thermM boundary layer. It is also found that the velocity and temperature fields decrease with the increase in the sink parameter.

关键词： magnetohydrodynamics (MHD) suction source/sink Prandtl number permeability boundary layer

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展会礼品：“精准”和“精美”同样重要

中国制衣 2007年第4期 40-41页

作者： kain lu

袋子越做越大,画册越来越多,参展商为强化人们的印象绞尽脑汁,然而,一定是又大又重的赠品才能有好的效果吗?品牌宣传画册和小礼物怎样设计,才能让人乐于接受和保存?

关键词：礼品展会参观者企业信息参展商画册资料工作人员品牌宣传宣传单

功函促进钼基异质结电催化剂的电子结构重整提升其析氢反应活性（英文）

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Science China Materials 2025年第1期 189-198页

作者：陈想冯帅谢松苗亚萍高标张旭明黄莉李筠 Paul k.Chu 彭祥 Hubei key Laboratory of Plasma Chemistry and Advanced Materials Engineering Research Center of Phosphorus Resources Development and Utilization of Ministry of Education School of Materials Science and Engineering Wuhan Institute of Technology School of Textile Science and Engineering Xi'an Polytechnic University The State key Laboratory of Refractories and Metallurgy Institute of Advanced Materials and Nanotechnology Wuhan University of Science and Technology Guizhou Wujiang Hydropower Development Co. Ltd. Department of Physics Department of Materials Science and Engineering and Department of Biomedical Engineering City University of Hong Kong

Mo基催化剂在电催化析氢反应（HER）中具有巨大应用潜力.然而,其活性位点的暴露不足、极强的氢吸附能力导致其催化性能未能充分体现.本文在碳布上构筑了Mo2N–MoSe2异质结（MNS）,以增强Mo基催化剂的HER活性.由于MNS中的Mo2N具有较低的...

Mo基催化剂在电催化析氢反应（HER）中具有巨大应用潜力.然而,其活性位点的暴露不足、极强的氢吸附能力导致其催化性能未能充分体现.本文在碳布上构筑了Mo2N–MoSe2异质结（MNS）,以增强Mo基催化剂的HER活性.由于MNS中的Mo2N具有较低的功函数,能够在异质界面产生内建电场,显著提高了其在HER中电荷转移效率.此外,MNS中原子之间的强电子相互作用优化了Mo位点的电子结构,降低了氢吸附能力,进一步增强了其本征催化活性.因此, MNS催化剂产生20 m A cm-2和1 A cm-2的析氢电流密度所需的过电位仅为65和210 mV, Tafel斜率仅为96 mV dec-1.此外, MNS在1 A cm-2电流密度下稳定运行240小时后,形貌、结构和性能均无明显变化.以上研究结果为工业大电流制氢所需的非贵金属基电催化剂的设计和合成提供了新思路.

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Spontaneous emission in the ellipsoidal nanocrystals

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Journal of Rare Earths 2009年第4期27卷 637-640页

作者： k.k.Pukhov General Physics Institute Russian Academy of Sciences 38 Vavilov Str.Bld.D Moscow 119991 Russia

The equation was presented for the spontaneous emission rate Anano of the two-level optical centers in the subwavelength eilipsoi- dal nanocrystals embedded in a dielectric medium. An important result was that the ratio Anano/Abulk could be estimated without recourse to a particular local-field model. On the ground of this equation the expression was derived for linestrength of electric-dipole transition in trivalent rare-earth ions. The applicability of the Judd-Ofelt equation for nanoparticles was discussed.

关键词： spontaneous emission lifetime nanocrystals Judd-Ofelt parameters rare earths

Preparation of Sm2O3 and Co3O4 from SmCo magnet swarf by hydrometallurgical processing in chloride media

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Journal of Rare Earths 2018年第7期36卷 725-732页

作者： k.Sahoo A.k.Nayak M.k.Ghosh k.Sarangi CSIR-Institute of Minerals and Materials Technology Bhubaneswar-751013OdishaIndia

The recycling of rare earth elements（REE） from end-of-life REE based products is an environment friendly proposition. Waste Sm-Co based permanent magnet generated during machining is a good source for both Sm and Co. In the present study a simpler process of acid leaching at 80 ℃ followed by solvent extraction, oxalate precipitation and calcination is described for producing pure Sm2 O3 and Co3 O4. With either 10 vol% H2SO4 or 15 vol% HCI at 80 ℃ more than 95% Sm and Co are leached in 1 *** of Sm from sulphate leach liquor with TBP or Aliquat 336 was poor. Although extraction with TOPS-99 is quantitative but Sm from sulphate leach liquor precipitated as Sm2（SO4）3·8 H2O. The chloride leach liquor at an initial pH of 2.5 and with 1.2 mol/L TOPS-99 shows requirement of 4-stages at A：O = 3：2. Stripping with oxalic acid precipitates Sm-oxalate which is calcined at 800 ℃ to produce Sm2 O3. Co3 O4 is recovered from the raffinate through oxalate precipitation followed by calcination at450℃.

关键词： SmCo magnet Samarium Cobalt TOPS-99 Solvent extraction Precipitation stripping

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声乐完整教程由浅至深的声乐指南

2022年中国新生儿协作网极早产儿红细胞输注现况分析

2014年

作者：（英）罗杰·凯恩（Roger kain）

本书主要内容包括：音域；开声；胸声；力量肌和胸声；用胸声唱高音；男生混合头声的奇妙声音；女生混合声；极端混合声；联合大声；超低音；解决问题等。

ISBN: (纸本)9787549552139

关键词：教材声乐

来源：畅想之星图书光盘版（南... 评论

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畅想之星图书光盘版（南通市图书馆镜像）

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中华儿科杂志 2025年第1期63卷 55-61页

作者：莫艳钱爱民白瑞苗李淑涓玉小清王瑾 Lee Shoo k. 蒋思远韦秋芬周文浩国家儿童医学中心复旦大学附属儿科医院新生儿科上海南京医科大学附属儿童医院新生儿医疗中心南京西北妇女儿童医院新生儿科西安广西壮族自治区妇幼保健院新生儿医疗中心南宁加拿大西奈山医院母婴健康研究中心多伦多M5GX 广州市妇女儿童医疗中心新生儿医学中心广州

目的分析2022年中国新生儿协作网(CHNN)各单位极早产儿(出生胎龄<32周)红细胞输注治疗的状况。方法基于CHNN极早产儿队列的横断面研究, 纳入2022年生后24 h内收入CHNN 89家单位的6 985例极早产儿。排除合并严重先天畸形及放弃治疗或转至... 详细信息

目的分析2022年中国新生儿协作网(CHNN)各单位极早产儿(出生胎龄kruskal-WallisH检验及Mann-WhitneyU检验等进行组间比较, 采用Cochran-Armitage和Jonckheere-Terpstra趋势检验进行不同出生胎龄及不同呼吸支持水平间的趋势检验。结果 6 985例极早产儿中男3 865例(55.3%), 出生胎龄为30.0(28.6, 31.0)周, 出生体重为(1 302±321)g。红细胞输注组3 617例(51.8%), 未输注组3 368例(48.2%)。出生胎龄<28、28～31周的极早产儿红细胞输注率分别为77.7%(893/1 150)、46.7%(2 724/5 835)。红细胞输注组极早产儿共接受9 616次红细胞输注, 输注时需有创呼吸支持的有2 459次(25.6%), 无创呼吸支持4 934次(51.3%), 无呼吸支持的有2 223次(23.1%)。因632次红细胞输注输血前血红蛋白未记录, 8 984次红细胞输注纳入分析。红细胞输注组母亲合并妊娠期高血压比例高于未输注组(χ2=10.73, P=0.001), 剖宫产出生、母亲产前激素应用比例均低于未输注组(χ2=12.00、12.93, 均P<0.001);与未输注组相比, 红细胞输注组患儿出生胎龄更小、出生体重更低, 小于胎龄、多胎以及第5分钟Apgar评分≤3分比例均更高, 女性、本院出生以及延迟脐带结扎比例均更低, 入院时生理稳定性转运风险指数评分更高(均P<0.05)。红细胞输注组极早产儿红细胞输注次数为2(1, 3)次, 首次红细胞输注时为18(8, 29)日龄, 首次红细胞输注前血红蛋白为97(86, 109)g/L。红细胞输注时≤7日龄的极早产儿有创呼吸支持、无创呼吸支持和无呼吸支持组接受红细胞输注前的血红蛋白水平差异无统计学意义(H=5.59, P=0.061);8～21以及≥22日龄的极早产儿不同呼吸支持状况下接受红细胞输注前的血红蛋白水平差异均有统计学意义(H=10.91、39.19, 均P<0.01)。8～21日龄、≥22日龄无呼吸支持的极早产儿阈值上红细胞输注分别为90.1%(264/293)、91.1%(1 578/1 732)。阈值上输血组极早产儿相比阈值下输血组发生坏死性小肠结肠炎的比例更高(χ2=10.59, P=0.001), 住院时间更长(Z=4.67, P<0.001)。结论 2022年CHNN纳入的极早产儿红细胞输注率较高, 接受红细胞输注前的血红蛋白水平普遍高于现有证据推荐的输注阈值。

关键词：婴儿, 早产红细胞输注重症监护病房, 新生儿

Tuning the Microstructural and Magnetic Properties of ZnO Nanopowders through the Simultaneous Doping of Mn and Ni for Biomedical Applications

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Journal of Materials Science & Technology 2015年第11期31卷 1111-1117页

作者： k.karthika k.Ravichandran Post Graduate & Research Department of Physics AVVM Sri Pushpam College(Autonomous)

Undoped and Mn＋Ni doped ZnO nanopowders were synthesized using a simple soft chemical route by varying the Ni doping level （1, 3, 5 and 7 at.%） and keeping the Mn doping level （10 at.%） constant, X-ray diffraction studies reveal that the incorporated Ni^2＋ ions form a secondary phase of cubic NiO beyond the Ni doping level of 3 at.%, which is also confirmed by Fourier transform infrared spectroscopy. The band gap of the nanopowders increases （from 3.32 to 3.44 eV） up to 3 at.% of Ni doping and decreases with further doping. ZnO：Mn：Ni nanopowders with 3 at.% of Ni concentration exhibit good antibacterial efficiency. The variation in the size of the nanoparticles, as observed from the TEM images and hydroxyl radicals as evidenced from the photoluminescence results, clearly substantiate the discussion on the antibacterial efficiency of the synthesized nanopowders. Magnetic properties of the synthesized nanopowders were studied using a vibrating sample magnetometer, and the results showed that the doping of Mn and Ni largely influences the magnetic properties of ZnO nanopowders.

关键词： ZnO Nanopowders Soft chemical route Magnetic properties Antibacterial activity

Investigation on the Reduction of Center of Mass Oscillations of Flexible Flapping Fins

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Journal of Bionic Engineering 2016年第4期13卷 544-557页

作者： Ashok k kancharala Michael k Philen Aerospace and Ocean Engineering Virginia Polytechnic Institute and State University Blacksburg VA 24061 USA

Nature has been a source of inspiration for developing advanced autonomous aerial and underwater vehicles. The bodies with flapping appendages produce Center of Mass （COM） oscillations as the flapping fins generate forces oscillatory in nature. The vehicles with larger COM oscillations pose the problems of control and maneuverability and this paper discusses the effect of flexibility and other operating parameters such as heaving, pitching amplitudes and operating frequency on COM oscillations. A detailed theoretical investigation has been carried out to predict the optimal operating parameters along with the fin stiffness to reduce the COM oscillations for a given Self-Propelled Speed （SPS）. Experiments have been performed to validate the theoretical results. It has been observed that the flexible fins operating at larger frequencies produce lower COM oscillations compared to stiffer fins operating at lower frequencies for a given mean thrust/SPS, and that the trailing edge amplitude along with the deformation pattern play a role in the generation of COM oscillations.

关键词： flapping fin fluid-structure interaction optimization digital image correlation