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D类放大器的未来趋势——改善音质与系统性能

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电子产品世界 2005年第07B期12卷 100-101页

作者： sean davis Cirrus Logic公司

传统的D类放大器在通过功率MOSFET进行放大前,需使用一个控制器将模拟或数字音频转换为脉宽调制(PWM)信号,这个控制器一般集成在一个功率后端器件当中.这类放大器拥有高效率的优点,可采用小型(或不使用)散热器,并降低电源输出的功率要求... 详细信息

传统的D类放大器在通过功率MOSFET进行放大前,需使用一个控制器将模拟或数字音频转换为脉宽调制(PWM)信号,这个控制器一般集成在一个功率后端器件当中.这类放大器拥有高效率的优点,可采用小型(或不使用)散热器,并降低电源输出的功率要求.然而,与A类和B类放大器相比,这类放大器在成本、性能和电磁干扰(EMI)等方面的存在着固有的系统问题.在设计人员的不懈努力下,现代D类解决方案与以往推出的产品相比在性能方面已有了长足的进步,系统更为耐用,音质也更加完美.

关键词： D类放大器系统性能未来趋势功率MOSFET 音质 B类放大器音频转换电磁干扰设计人员控制器高效率散热器信号脉宽器件电源 A类

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D类放大器的发展趋势

今日电子 2005年第9期 63-64页

作者： sean davis Cirrus Logic公司

数字放大器改善了音频质量和系统性能.D类放大器在过去的几代产品中已经得到了巨大的发展,系统设计者极大地改善了系统的耐用性并提高了其音频质量.实际上,对大多应用而言,使用这些放大器所带来的好处已经远远超过了它们的不足.

关键词： D类放大器发展趋势系统性能音频质量数字放大器系统设计者耐用性

Packaging and Performance of 980nm Broad Area Semiconductor Lasers

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电子与封装 2006年第3期6卷 6-14页

作者： XingshengLiu LawrenceC.Hughes MichaelH.Rasmussen Martin H.Hu Venkata A Bhagavatula Ronald W.davis sean Coleman Rajaram Bhat Chung-En Zah Science ＆ Technology Center SP-PR-02-1 Corning NY 14831 U.S.A

High power broad area semiconductor lasers have found increasing applications in pumping of solid state laser systems and fiber amplifiers, frequency doubling, medical systems and material processing. Packaging including the assembly design, process and thermal management, has a significant impact on the optical performance and reliability of a high power broad area laser. In this paper, we introduce the package structures and assembling process of 980nm broad area lasers and report the performances including output power, thermal behavior and far *** will report two types of high power broad area laser assemblies. One is a microchannel liquid cooled assembly and the other is a conduction cooled CT-mount assembly .Optical powers of 15W and 10W were achieved from a 980nm broad area laser with a 120μm stripe width in a microchannel liquid cooled assembly and conduction cooled CT-mount assembly, respectively .Furthermore, a high power of 6.5 W out of fiber was demonstrated from a pigtailed, fully packaged butterfly-type module without TEC ( Thermoelectric cooler ).The measurement results showed that thermal management is the key in not only improving output power, but also significantly improving beam divergence and far field distribution. The results also showed that the die attach solder can significant impact the reliability of high power broad area lasers and that indium solder is not suitable for high power laser applications due to electromigration at high current densities and high temperatures.

关键词：半导体激光器封装性能电迁移激光组装测试

Blood biomarkers of Alzheimer’s disease:important considerations for use in clinical practice

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Neural Regeneration Research 2025年第1期20卷 205-206页

作者： Sarah Fullam sean O’Dowd Antoinette O’Connor Department of Neurology Tallaght University HospitalDublinIreland Academic Unit of Neurology Trinity College DublinIreland

Introduction:Fluid and positron emission tomography(PET)biomarkers that enable the detection of the hallmark proteins of Alzheimer’s disease(AD)(amyloid and tau)have revolutionized our approach to the diagnosis of *** evolution of AD diagnostic criteria to include biological characterization(Alzheimer’s Association Working Group,2023)provides an appropriate framework to reduce levels of clinico-pathologic mismatch and improve in-vivo diagnostic *** the therapeutic landscape for neurodegenerative disease evolves,it is increasingly incumbent on clinicians to provide timely,and pathologically precise diagnoses for ***,the expensive and invasive nature of these tests limits their scalability.

关键词： Blood Alzheimer diagnosis

Direct Air Carbon Capture Takes Baby Steps-Giant Strides Are Needed sean O’Neill

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Engineering 2022年第1期8卷 3-5页

作者： sean O’Neill Senior Technology Writer

In September 2021,the world’s largest industrial plant to pull carbon dioxide(CO_(2))directly out of the atmosphere officially became operational in *** and built by the Zurich,Switzerland-based company Climeworks,it... 详细信息

关键词： remove store permanent

VOC removal from contaminated groundwater through membrane pervaporation. (Ⅱ): 1,1,1-trichloroethane-SDS surfactant solution system

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Journal of Environmental Sciences 2003年第6期15卷 821-826页

作者： sean LIU Department of Food Science Rutgers University

The conventional “pump-and-treat' technology for subsurface remediation of groundwater contaminated with volatile organic compounds(VOCs) such as 1,1,1-trichloroethane(TCA), a common chlorinated organic solvent, has limitation of prohibitively long treatment time due to extremely low water solubility of the VOCs. Surfactant-based soil remediation has emerged as the effective technology that substantially reduces the treatment time. In order to make the whole process economical, the surfactant used in soil washing has to be recovered and reused. This study examined the recovery of anionic surfactant, sodium dodecyl sulfate(SDS), from soil remediation fluids containing TCA, using a bench-scale membrane pervaporation unit. The effects of high TCA concentration, surfactant dosage, and flow rate on permeation flux and selectivity(α value) of the process were evaluated. In general, higher surfactant concentration yielded lower TCA flux and constant water flux, resulting in declining α values; higher flow rate of TCA feed stream results in higher VOC flux and selectivity, an indication of the effect of concentration polarization; higher TCA feed concentration produces higher TCA permeation across the membrane, however, the selectivity was virtually unchanged unless the total TCA concentration exceeded 2000 ppm.

关键词： pervaporation VOCs SDS surfactant groundwater remediation 1,1,1-trichloroethane

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XML by example building E-Commerce applications sean McGrath.

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Assessment of semi-empirical mass transfer correlations for pervaporation treatment of wastewater contaminated with chlorinated hydrocarbons

1998年

作者： sean McGrath.

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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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2006年第11期7卷 1911-1916页

作者： LIU sean X. Department of Food Science Rutgers University New Brunswick NJ 08901-8520 USA

Assessment of mass transfer characteristics of pervaporation （PV） treatment of wastewater contaminated with chlorinated hydrocarbons is of great importance for water treatment plant operators conducting initial evaluation, process optimization, and process economics. While a membrane plays a central role in pervaporation processes and separation efficiency, the mass transfer in the liquid layer next to the membrane surface is of equal, if not greater importance. It is one of the few process parameters that can be adjusted in situ to manipulate the outcome of a pervaporation process. In this study, a bench scale pervaporation experiment of removing a common chlorinated hydrocarbon from water was carried out and the results of it were compared to the ones based on well-known semi-empirical correlations. The mass transfer coefficients from the experiments, ranging from 0.8× 10^-5-2.5× 10^-5 m/s under the operating conditions, are higher than those predicted by the correlation. The corresponding separation factors under varying flow velocities are determined to be between 310-950.

关键词： Chlorinated hydrocarbon Mass transfer Pervaporation Wastewater treatment

Molten salt assisted self-activated carbon with controllable architecture for aqueous supercapacitor

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Journal of Materials Science & Technology 2023年第25期156卷 107-117页

作者： Wei Zhang Wenxian Li sean Li School of Materials Science and Engineering The University of New South WalesKensingtonNew South Wales 2052Australia UNSW Materials and Manufacturing Futures Institute The University of New South WalesKensingtonNew South Wales 2052Australia

Activated carbons have been widely employed as electrode materials of aqueous supercapacitors but the use of hazardous and corrosive activating agents challenges conventional activation ***,using a unique molten salt assisted self-activation technique,we have devised an eco-friendly and simple method to synthesize oxygen-rich hierarchical porous carbon with controllable *** of sodium carboxymethylcellulose and NaCl was pyrolyzed in one step,creating in-situ produced Na_(2)CO_(3)-NaCl molten salt that carried out the activation ***2 CO3 acts as the activating agent in the reaction media of NaCl during the self-activation *** obtained carbon exhibited a remarkable specific capacitance of 278 F g^(−1) at 0.5 A g^(−1) and retained 76%capacitance at 50 A g^(−1) in a three-electrode *** fabricated aqueous coin cell achieved 81%capacitance retention at 50 A g^(−1) and the highest specific energy density of 12.8 Wh kg^(−1) at 214.6 W kg^(−1),which are superior compared to the commercial activated carbon(64%at 50 A g^(−1) and 8.4 Wh kg^(−1) at 194.8 W kg^(−1)).Moreover,capacitance fading was not observed after 10000 cycles at 5 A g^(−1).Considering the species diversity and low cost of self-salt polymers on the market,this strategy will expect to become a scalable approach for synthesizing high-performance capacitive carbons.

关键词： Molten salt Self-template Porous carbon Controllable architecture Aqueous supercapacitors