Results 1 to 10 of about 3,903 (156)
为提高茶皂苷的提取率,扩大茶皂苷的应用范围,以脱脂油茶籽饼为原料,采用超声-微波辅助法提取茶皂苷。以油茶皂苷提取率为考察指标,在单因素试验的基础上,采用Plackett-Burman试验设计筛选出具有显著影响的试验因素,再通过响应面法对茶皂苷提取工艺进行优化。另外,将超声-微波辅助法提取茶皂苷的工艺与超声辅助法和微波辅助法提取工艺进行了对比。结果表明:超声-微波辅助法提取茶皂苷的最佳工艺条件为乙醇体积分数59%、料液比1∶ 12、提取液pH 7、超声功率475 W、超声时间4 min、超声工作2 ...
司喜艳,王香玉,皇甫新燕,王琦,赵仁勇SI Xiyan, WANG Xiangyu, HUANGFU Xinyan, WANG Qi, ZHAO Renyong
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Research progress on preparation and physicochemical properties of coal-based graphene quantum dots [PDF]
Graphene quantum dots (GQDs) have attracted great research interest due to their remarkable quantum confinement and edge effects. In addition to exhibiting stable photoluminescence, it also has many advantages such as low cytotoxicity, good solubility ...
Jidun SHA +5 more
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Optimization of Solanum lyratum Crude Polysaccharide Extraction Process Using Response Surface Methodology and Analysis ofIts In Vitro Antioxidant Activity [PDF]
To optimize the extraction process of polysaccharide form Solanum lyratum and investigate its in vitro antioxidative activity. In this study, response surface methodology was employed to optimize the ultrasonic-assisted extraction process of ...
Lijuan DENG, Minghao HUANG, Taiqi HUANG
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ABSTRACT Objective To develop a standardized sonographic evaluation and reporting system for Cesarean scar pregnancy (CSP) in the first trimester, for use by both general gynecology and expert clinics. Methods A modified Delphi procedure was carried out, in which 28 international experts in obstetric and gynecological ultrasonography were invited to ...
I. P. M. Jordans +18 more
wiley +1 more source
First‐trimester ultrasound detection of fetal heart anomalies: systematic review and meta‐analysis
ABSTRACT Objectives To determine the diagnostic accuracy of ultrasound at 11–14 weeks' gestation in the detection of fetal cardiac abnormalities and to evaluate factors that impact the detection rate. Methods This was a systematic review of studies evaluating the diagnostic accuracy of ultrasound in the detection of fetal cardiac anomalies at 11–14 ...
J. N. Karim +26 more
wiley +1 more source
ABSTRACT Objectives Preterm birth (PTB) accounts for two‐thirds of deaths of structurally normal babies and is associated with substantial lifetime healthcare costs. Prevention of PTB remains limited by the modest accuracy of prediction methods, namely transvaginal ultrasound (TVS) cervical length (CL) measurement and quantitative cervicovaginal fetal ...
D. O. C. Anumba +4 more
wiley +1 more source
Design and experimental research of pipeline stress measurement system based on alternating current field [PDF]
Ferromagnetic pipelines are prone to stress distortion during service, which will likely cause destructive defects, such as fatigue damage and cracks, and even major safety accidents in severe cases.
Anquan WANG +7 more
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ABSTRACT Objective To investigate how many examinations it takes to be able to identify the pelvic parts of the ureters on transvaginal sonography (TVS). Methods This was a prospective study including consecutive women attending a gynecological outpatient clinic in a tertiary referral setting.
M. K. Aas‐Eng +5 more
wiley +1 more source
Novel Antifouling Technology Research: Progress and Prospects [PDF]
海洋生物污损问题给海洋事业的发展带来了许多危害,传统防污技术已日渐不能满足要求,研发新型环境友好型防污剂迫在眉睫.用仿生学原理和化学生态学的方法发展新型无毒仿生防污材料和技术是解决海洋污损问题的新思路.本文综述了污损生物防除技术的发展,并重点介绍了基于化学生态学发现的仿生抗生物附着先导化合物和防污材料 ...
chxia@yic.ac.cn +6 more
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Analysis on flow characteristics and aerodynamic-force-induced vibration of supersonic rocket-sled
目前, 火箭橇试验是飞行器空气动力学重要试验手段, 然而强烈的地面与轨道干扰会影响试验的精度, 甚至导致试验失败。采用尺度自适应SAS方法和基于铺层算法的动网格技术对不同马赫数下的超声速火箭橇滑行过程进行数值模拟, 探究了超声速火箭橇的气动力致振机理。采用了数值风洞模拟方法对超声速火箭橇无限空间绕流和仅包含地面的橇体绕流进行仿真, 分析了不同环境条件下的激波特征。结果表明: 超声速火箭橇的头激波传播至轨道和地面时会发生激波反射, 反射激波的存在会导致超声速火箭橇产生升力, 并带来阻力的略微增加 ...
YU Yuanyuan +5 more
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