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阳离子聚丙烯酰胺类絮凝剂PAD的合成及优化
丙烯酰氧乙基二甲基苄基氯化铵 丙烯酰胺 阳离子聚丙烯酰胺类絮凝剂 响应曲面法
2020/11/9
为了提高阳离子絮凝剂的絮凝性能，选用阳离子疏水表面活性单体DBC和亲水单体AM，以EDTA-2Na为络合剂，以AIBN和APS-NaHSO3为复合引发剂，采用水溶液聚合法制得一种新型阳离子聚丙烯酰胺类絮凝剂P(AM-DBC) (PAD)。此方法具有工艺操作简单、无需添加其他模板和表面活性剂、产物的相对分子质量高和转化率高等优势。单因素实验结果表明，当总单体质量分数为40%、单体摩尔比n(AM)∶n...
为简化对车辆侧倾动力学的研究特别是对车身侧倾角的估算和控制，提出针对车身侧倾角的Padé模型降阶方法。该文首先建立了线性三自由度车辆模型，并在此基础上推导出了车身侧倾角的传递函数，由于此传递函数的高阶特性难以用于车辆侧倾动力学的计算与控制中，所以接着对所推导出的侧倾角传递函数进行降阶处理。又考虑到车身侧倾的低频特性以及Padé模型降阶法在低频区能有较好的拟合效果，该文采用Padé模型降阶法对车身侧...
运用HPM-Padé(同伦摄动-帕德逼近)法导出了当喷注流体速度与距平板前缘距离的平方根成反比时,不可压缩常物性流体外掠平板层流边界层内无量纲速度和无量纲温度解析表达式,无量纲流函数1阶导数的HPM-Padé解析解与4阶龙格库塔法的数值解结果一致.利用HPM-Padé解析解研究了喷注系数和流体Prandtl数对速度和温度分布的影响.结果表明:Prandtl数越大,温度边界层越薄,壁面温度梯度越大;...
由联想的乐phone和乐pad所引起对设计的思考（图）
联想 乐phone 乐pad 设计
2011/6/7
“山寨”是依靠抄袭、模仿、恶搞等手段发展壮大起来，反权威、反主流且带有狂欢性、解构性、反智性以及后现代表征的亚文化的大众文化现象。听起来，这山寨一词也颇有文化背景，貌似设计史中的后现代主义阶段，反对理性现代主义、国际主义统一天下的局面，力争多样化、平民化的文化趋势，反对产品独裁。
Stability Analysis on Rotor Systems Supported by Self-acting Tilting-pad Gas Bearings with Frequency Effects
bearing-rotor system tilting-pad bearing logarithm attenuation rate
2011/8/4
The recent research on stability of gas bearing-rotor systems still mostly adopts the same method as in oil-lubricated bearing-rotor systems. The dynamic coefficients of gas bearings in the case that ...
NASA's Shuttle Atlantis Moves to Launch Pad, Liftoff Practice Set
NASA's Shuttle Atlantis Pad, Liftoff Practice Set
2010/4/29
Journalists are invited to cover the STS-132 space shuttle crew's Terminal Countdown Demonstration Test, a practice countdown and related training, April 20-23 at NASA's Kennedy Space Center in Florid...
NASA's Space Shuttle Discovery Rolls to Launch Pad; Liftoff Practice Set
NASA's Space Shuttle Discovery Pad Liftoff Practice Set
2010/4/29
Journalists are invited to cover the STS-131 space shuttle crew's practice countdown and related training March 2-5 at NASA's Kennedy Space Center in Florida. Reporters also may cover space shuttle Di...
NASA Shuttle at Launch Pad for Final Scheduled Night Launch; Crew Set to Arrive for Practice Liftoff
NASA Shuttle Final Scheduled Night Launch Practice Liftoff
2010/1/11
After reaching its launch pad at NASA's Kennedy Space Center in Florida Wednesday, space shuttle Endeavour now awaits its next major milestone for the upcoming STS-130 mission. Reporters are invited t...
Employment of alumina suspension pad for v-bending of SUS304 strip
Plastic forming Sheet metal forming Bending
2009/12/2
Purpose: Authors have suggested employment of dilatant fluid for metal forming tools, and report an application
on v-bending of thin stainless steel strips in this paper.
Design/methodology/approach...
Investigation of the coatings applied onto brake discs on disc-brake pad pair
coating improving disc performance Disc Thickness Variation (DTV)
2009/10/23
While braking, according to the severity of it, thermal, metallurgical, constructive and tribological occurrences emerge on the brake disc-pad interface. In this study, NiCr was sprayed as bonding lay...
NASA's Shuttle Program Hands Over Launch Pad to Constellation
NASA Shuttle Program Launch Pad Constellation
2009/6/3
The May 31 transfer of Launch Pad 39B at NASA's Kennedy Space Center in Florida from the Space Shuttle Program to the Constellation Program is the next step in preparing the first flight test of the a...
分段Padé逼近法用于预测二维介质柱的单站RCS方向图
矩量法 分段Padé逼近法 雷达散射截面
2009/5/6
矩量法与分段Padé逼近法结合用于预测任意形状截面二维介质柱的单站RCS方向图。该方法采用以总电场为未知函数的微积分方程。在矩量法过程中，用共轭梯度法和快速傅里叶变换(CG-FFT)的组合算法求解线性方程组，以便降低存储量和加快迭代速度。分段Padé逼近法用于加速获取单站RCS方向图。这里为分段Padé逼近法增添了一个自适应算法,克服了以往人工选择展开点位置的缺点，这种新的组合算法称为CG-FFT...
一种基于Padé逼近对短时序列频率和品质因数的估计方法
Padé逼近 FFT 小波变换
2009/4/3
该文提出了一种基于Padé逼近的谱估计方法.由于Padé通近能够利用有限项很好地逼近对无限项的求和,文中算法适用于短时序列情况.经过实验仿真并与FFT方法和小波变换谱估计方法进行比较表明,该文算法具有较高的频率分辨率和估计精度,并具有较好的品质因数.
Employment of concentrated-hardsphere-suspension pad for V-bending of thin strip
Plastic forming Sheet metal forming Bending Easy tool
2010/1/20
Purpose: Authors have suggested employment of dilatant fluid for metal forming tools, and report an application
on v-bending of thin stainless steel strips in this paper.
Design/methodology/approach...
Repair of magnesium alloy castings by means of welding and pad welding
Metallic alloys Magnesium alloys Welding
2010/2/22
Purpose: Attempts were carried out at pad welding and welding of castings made of alloy AZ91D. Technologies were developed to repair such castings by means of welding methods encompassing the choice o...