Results 31 to 40 of about 11,500 (168)

Effect of aspirin on maternal hemodynamics in Chinese women at high risk for preterm pre‐eclampsia: longitudinal study

open access: yesUltrasound in Obstetrics &Gynecology, Volume 66, Issue 5, Page 621-630, November 2025.
ABSTRACT Objectives To compare the maternal hemodynamics of Chinese women at low and at high risk for preterm pre‐eclampsia (PE) and assess the differences in hemodynamic parameters between high‐risk women with or without prophylactic aspirin. Methods This was a prospective longitudinal case–control study of 857 Chinese women with a singleton pregnancy
X. Wang   +11 more
wiley   +1 more source

合闸开关选相对容量试验的影响研究

open access: yesGaoya dianqi, 2017
容量试验中短路电流直流分量的大小直接影响电流过零点的di/dt与TRV,对直流分量的精确控制直接关系到试验质量与效率。容量实验室通常控制3台独立的合闸开关分别进行选相合闸以产生满足要求的直流分量。文中运用理论分析方法找出了产生完全对称短路电流和最大非对称短路电流的选相方法,并对一种含有Y/△变压器的回路进行了分析,总结了根据电流波形判断合闸开关关合顺序的方法。
张晋波   +4 more
doaj  

Design of Carrier Synchronization Based on Costas Loop [PDF]

open access: yes, 2010
介绍了平方变换法相干解调原理,从工程角度完善了载波提取的电路结构,消除了频移载波的误锁问题.提出用科斯塔斯环法来实现从2dPSk信号中提取相干载波,解决了提取的载波信号存在180度的相位含糊问题,为通信系统提高抗噪性能提供了条件.当载波频率很高时,工作频率较低的科斯塔斯环易于实现.并用SIMulInk设计出科斯塔斯环法提取载波的仿真电路图和进行相应的仿真实验.Theory of coherent demodulation based on method of square counterchange ...
刘美珍   +3 more
core  

Beyond Motivation: Modeling the Predictive Role of L2 Pride in Informal Digital Learning of English

open access: yesInternational Journal of Applied Linguistics, Volume 35, Issue 4, Page 1938-1952, November 2025.
ABSTRACT This study investigates the role of second language (L2) pride—an understudied affective factor—in shaping learners’ language learning motivation and involvement with informal digital learning of English (IDLE). Drawing on questionnaire data from 1388 Chinese university EFL students, the study employs structural equation modeling to examine ...
Minlin Minny Zou   +3 more
wiley   +1 more source

大容量试验短路电流波形参数的测算

open access: yesGaoya dianqi, 2019
采用抛物线拟合方法计算大容量试验短路电流波形的峰值和对应的时间坐标。理论证明短路电流波形上相邻两峰值的时间坐标中点的电流值近似等于此时的直流分量值,并据此给出波形的直流时间常数、交流(基波)分量有效值和直流分量百分数的算法。使用STL提供的标准短路电流波形,对文中算法和现有算法进行了对比测试。测试结果验证了该算法的准确性,同时表明,仅使用3个峰值点并未显著降低文中算法在计算交流分量恒定的短路电流波形参数时的准确度。通过计算直流时间常数不同 ...
周小猛   +4 more
doaj  

Clip Voice: Misogyny and the Renegotiation of a Gendered Vocal Style in Chinese Digital Discourse

open access: yesJournal of Sociolinguistics, Volume 29, Issue 5, Page 348-359, November 2025.
ABSTRACT The participatory culture of social media allows women's voices to be heard but also parodied and policed. On Chinese social media platforms, where performers rapidly adopt and transform vocal trends for engagement, discourse on gendered vocal styles has proliferated.
Zichuan Yu, Rebecca Lurie Starr
wiley   +1 more source

±800 kV直流分压器校准分析计算模型研究与应用

open access: yesGaoya dianqi, 2017
直流分压器是特高压直流输电系统中不可缺少的主设备,其采集数据的准确性对电网的安全稳定运行至关重要。基于直流分压器的工作原理,分析致使直流分压器分压比变化的主要因素,通过数学公式直观的诠释分压比的不确定性,然后在研究分压比不确定性的基础上构建直流分压器校准分析计算模型,并试验证明了该模型对站用±800 kV直流分压器的校准水平高达10-510-6量级,大幅度提升了直流分压器量值测量的准确度。
王奇   +4 more
doaj  

利用TMS320C54x数字信号处理器进行JPEG算法的彩色图像压缩 [PDF]

open access: yes, 2000
作为水底勘探设备的一个重要组成部分,水下彩色图像采集与传输系统主要由图像采集、图像压缩和信道编码传输三大部分组成。它必须具有小型化、高速处理的特点。而数字信号处理器(DSP),由于其独特小巧的结构和快速实现各种数字信号处理算法的突出优点,理所当然的成为了该系统核心的最佳选择。 在水下彩色图像采集与传输系统中,压缩是其中一个必不可少的环节。这是因为相比于黑白图像而言,彩色原始图像的表示需要更大量的数据。因此在进行传输之前,需要对图像信息进行数据压缩编码,以减少传输的数据量,更好地满足系统传输速率的要求 ...
王一帆
core  

Transformation of social‐ecological systems in the Songhua River Basin, Northeast China: Lessons for a more sustainable development

open access: yesPeople and Nature, Volume 7, Issue 7, Page 1749-1768, July 2025.
Abstract Social‐ecological systems (SES) are coupled systems formed by the intricate interactions between humans and nature. Our movement towards sustainable lifestyles requires a robust understanding of these interactions. Achieving a sustainable win‐win situation for both social and ecological systems, therefore, necessitates a sound scientific ...
Na Sa   +6 more
wiley   +1 more source

Virtual channel model for distributed video coding accounting for quantization noise [PDF]

open access: yes, 2012
Due to the inaccuracy model on describing the virtual channel with Laplacian,the rate-distortion performance of distributed video coding is relatively low.The quantization noise will be taken into account for online modeling at the decoder.Further,the ...
Ming YIN   +3 more
core  

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