EFFECTS OF ULTRASONIC RADIATION INTENSITY ON THE OXIDATION OF SINGLE-WALLED CARBON NANOTUBES IN A MIXTURE OF SULFURIC AND NITRIC ACIDS

RUI HE,XIBO PEI,LANLAN PAN,LINGYANG TIAN,Feng Luo,LEI SUI,QIANBING WAN,JIAN WANG 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2013 NANO Vol.8 No.4

One of the most commonly used techniques for purification and eventual dispersion of single-wall carbon nanotubes (SWNTs) is oxidation using strong acid and ultrasonication. Literature review reveals that ultrasonication of varying radiation intensities have been used during the acid oxidation, but few have reported whether ultrasonication of different intensities would have different effects on the structure and properties of SWNTs and how the effects are. An investigation of the effects of ultrasonic radiation intensity on SWNTs during oxidation in a mixture of sulfuric and nitric acids was conducted. Ultrasonication using different intensities (50 W, 100 W, 200 W and 300 W) was used. The acid-treated SWNTs were characterized by scanning and transmission electron microscopy, Fourier transform infrared spectroscopy, zeta potential test Boehm titration test and Raman spectrum analysis. Data from these experiments showed that high intensities provided stronger oxidizing conditions than lower ones. As ultrasonic intensity increased, larger number of SWNTs were destroyed and consumed to produce carbonaceous impurities, and more defects appeared in the tube walls.

Synthesis and characterization of core–shell associative polymer that prepared by oilfield formation water for chemical flooding

Rui Liu,Wan-Fen Pu,Dai-Jun Du 한국공업화학회 2017 Journal of Industrial and Engineering Chemistry Vol.46 No.-

A novel core–shell polymer (HBAPAM) with functionalized nano-SiO2 as core, multibranched associativepolymeric chains as shell was synthesized through in-situ free radical polymerization strategy. TGA, IR,1H NMR, and SEM proved the notion and method of preparing of HBAPAM was applicable. The core–shellstructure and multibranched morphology enhanced the supramolecular interaction of HBAPAM, whichdisplayed the desirable viscosified efficiency and viscoelasticity, especially, long-term stability in harshtemperature and salinity condition. HBAPAM featured the rheology in multiscale consistently indeionized water and formation water. Coreflooding experiments confirmed that HBAPAM had high costperformance in the variable permeability of oilfields.

Amphiphilically modified chitosan copolymer for enhanced oil recovery in harsh reservoir condition

Wan-Fen Pu,Rui Liu,Qin Peng,Dai-Jun Du,Qi-Ning Zhao 한국공업화학회 2016 Journal of Industrial and Engineering Chemistry Vol.37 No.-

A novel amphiphilically grafting natural chitosan copolymer (PAMCS) was prepared by using one stepwater-free radical polymerization strategy and the basic parameters for PAMCS were systematicallycharacterized. The rigid D-glucosamine unit, intermolecular association and hydrogen bondingsynergistically endowed PAMCS solution with rheological properties, super-high salt resistance andtemperature tolerance in harsh reservoir condition. PAMCS solution exhibited viscoelastic behaviorand formulated the unique displacement mechanism in comparison to that for partially hydrolyzedpolyacrylamide. Moreover, the mass concentration, injective rate and polymer solution slug related to oilrecovery efficiency for PAMCS were investigated from the economic point.

Chia Seed Supplementation Reduces Senescence Markers in Epididymal Adipose Tissue of High-Fat Diet-Fed SAMP8 Mice

Yehua Rui,Shengyi Yang,Li-hua Chen,Li-qiang Qin,Zhongxiao Wan 한국식품영양과학회 2018 Journal of medicinal food Vol.21 No.8

Adipose tissue is a key organ with substantial senescent cell accumulation under both obesity and aging conditions. Chia seed is an ancient seed and is the richest plant source of α-linolenic acid. We aimed to determine how cellular senescence markers will be altered in adipose tissue of senescence-accelerated mouse-prone 8 (SAMP8) mice fed with high-fat diets (HFDs); and how chia seed can affect the above markers. SAMP8 mice and their control senescence-accelerated mouse-resistant 1 (SAMR1) were divided into four groups, that is, SAMR1 low-fat diet group (R1LF), SAMP8LF group (P8LF), SAMP8 high-fat group (P8HF), and SAMP8HF group supplemented with 10% chia seed (P8HC). At the end of the intervention, body composition was measured through T1-weighted magnetic resonance imaging, and epididymal (EPI) and subcutaneous (SC) adipose tissues were dissected for further analysis. Compared with the R1LF group, the P8HF and P8HC groups had significantly increased body fat mass. In EPI fat, p16, CD68 and PAI-1 mRNA expression from P8HF group were significantly increased; chia seed partially reduced p16 and CD68 mRNA expression. The P8LF group has increased p16 and CD68, and the P8HF group has increased p16, p21, and CD68; and P8HC group has increased p16 mRNA expression. The protein expression of p-AMPK in EPI and SC fat from the P8HF group was reduced. In conclusion, reductions in AMPK activity might be partially responsible for elevation in HFD-induced senescence markers in both EPI and SC fat, and chia seed supplementation is able to reduce senescence-associated markers at least in EPI adipose tissue.

Performance and Spatial Succession of a Full-Scale Anaerobic Plant Treating High-Concentration Cassava Bioethanol Wastewater

( Gao Rui Fang ),( Xu Feng Yuan ),( Jia Jia Li ),( Xiao Fen Wang ),( Xu Cheng ),( Wan Bin Zhu ),( Zong Jun Cui ) 한국미생물 · 생명공학회 2012 Journal of microbiology and biotechnology Vol.22 No.8

A novel two-phase anaerobic treatment technology was developed to treat high-concentration organic cassava bioethanol wastewater. The start-up process and contribution of organics (COD, total nitrogen, and NH4+-N) removal in spatial succession of the whole process and spatial microbial diversity changing when sampling were analyzed. The results of the start-up phase showed that the organic loading rate could reach up to 10 kg COD/m3d, with the COD removal rate remaining over 90% after 25 days. The sample results indicated that the contribution of COD removal in the pre-anaerobic and anaerobic phases was 40% and 60%, respectively, with the highest efficiency of 98.5%; TN and NH4+-N had decreased to 0.05 g/l and 0.90 g/l, respectively, and the mineralization rate of total nitrogen was 94.8%, 76.56% of which was attributed to the anaerobic part. The microbial diversity changed remarkably among different sample points depending on the physiological characteristics of identified strains. Moraxellaceae, Planococcaceae, and Prevotellaceae were dominant in the pre-anaerobic phase and Bacteroidetes, Campylobacterales, Acinetobacter, Lactobacillus, Clostridium, and Bacillus for the anaerobic phase. Methanosarcinaceae and Methanosaeta were the two main phylotypes in the anaerobic reactor.

Calibration Practices in Clinical Mass Spectrometry: Review and Recommendations

Cheng Wan Ling,Markus Corey,Lim Chun Yee,Tan Rui Zhen,Sethi Sunil Kumar,Loh Tze Ping 대한진단검사의학회 2023 Annals of Laboratory Medicine Vol.43 No.1

Background: Calibration is a critical component for the reliability, accuracy, and precision of mass spectrometry measurements. Optimal practice in the construction, evaluation, and implementation of a new calibration curve is often underappreciated. This systematic review examined how calibration practices are applied to liquid chromatography-tandem mass spectrometry measurement procedures. Methods: The electronic database PubMed was searched from the date of database inception to April 1, 2022. The search terms used were “calibration,” “mass spectrometry,” and “regression.” Twenty-one articles were identified and included in this review, following evaluation of the titles, abstracts, full text, and reference lists of the search results. Results: The use of matrix-matched calibrators and stable isotope-labeled internal standards helps to mitigate the impact of matrix effects. A higher number of calibration standards or replicate measurements improves the mapping of the detector response and hence the accuracy and precision of the regression model. Constructing a calibration curve with each analytical batch recharacterizes the instrument detector but does not reduce the actual variability. The analytical response and measurand concentrations should be considered when constructing a calibration curve, along with subsequent use of quality controls to confirm assay performance. It is important to assess the linearity of the calibration curve by using actual experimental data and appropriate statistics. The heteroscedasticity of the calibration data should be investigated, and appropriate weighting should be applied during regression modeling. Conclusions: This review provides an outline and guidance for optimal calibration practices in clinical mass spectrometry laboratories.

Optimization for Solid Polymer Microstructure Replication using Gas-Assisted Hot Embossing under Low Pressure

Lei Wan,Ning Zhu,Xuan Li,Rui-ying Zhang,Ting Mei 한국정밀공학회 2016 International Journal of Precision Engineering and Vol.17 No.8

In order to realize the replication of high-quality polymer microstructures with vertical and smooth sidewalls, a gas-assisted hot embossing process with low pressure supplied was optimized to eliminate the swallowtail phenomenon during pattern transfer and simplify workpiece process setting. With help of passive alignment clamp, the rate of replication greater than 95.5% for vertical sidewalls was successfully obtained under the optimum process condition. Accordingly, a root mean square sidewall roughness of 4.6 nm was measured for polymer trenches in comparison with that of 5.7 nm for the silicon mold using a bevel-cut preparation technique. Furthermore, the rate of bulging of less than 15% for polymer workpiece was also obtained. The experiment has demonstrated that high-precise polymer pattern replication is related to both process settings and mold morphology sizes.

A study on avoiding joint limits for inverse kinematics of redundant manipulators using improved clamping weighted least-norm method

JUN WAN,Hongtao Wu,Rui Ma,Liang'an Zhang 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.3

A general method is presented for the inverse kinematics resolution of redundant manipulators with joint limits. The success of avoiding joint angular position limits of the original clamping weighted least-norm method is ascribable to the strength of the repulsive potential field function. However, the repulsive potential field function may lead to excessive joint angular velocities that can exceed the corresponding limits. We propose an improved clamping weighted least-norm method that adds an elastic field function into the original method for the sake of sustaining the constraints of joint angular velocity limits. Moreover, for hierarchical task-level construction, the priority of avoiding joint angular velocity limits is lower than that of avoiding joint angular position limits. To adequately illustrate the effectiveness of the proposed method, case studies were performed in comparison with other methods in singular configurations of a redundant manipulator.

The synergistic attractiveness effect of plant volatiles to sex pheromones in a moth

Yulei Fang,Rui Zeng,Shufang Lu,Luyao Dai,Xinlong Wan 한국응용곤충학회 2018 Journal of Asia-Pacific Entomology Vol.21 No.1

The effects of plant-derived chemicals (volatiles) on the attraction of the Spodoptera litura moth to sex pheromoneswere evaluated using an electroantennogram (EAG). Neuronal responses of male moths to sex pheromonemixtures (SPs) (a 9:1 mixture of synthetic (9Z,11E)-9,11-tetraddecadienyl acetate (Z9E11-14:OAc) and(9Z,12E)-9,12-tetradecadienyl acetate (Z9E12-14:OAc)) and to SPs mixtures with eight plant volatiles (benzaldehyde,(E)-β-caryophyllene, phenylacetaldehyde, 2,6-nonadienal, benzyl alcohol, racemic linalool, longifolene,and (E)-β-ocimene) were also measured. Then, wind tunnels and field trapping bioassays were conducted todetermine the influence of plant volatiles on S. litura moth behavioral responses to SPs. The results indicated thatbenzaldehyde, phenylacetaldehyde, and benzyl alcohol significantly enhanced, and longifolene, (E)-β-caryophyllene,and (E)-β-ocimene had no significant effect on the attractions to SPs, whereas racemic linaloolsignificantly decreased the attraction of male S. litura moths to SPs throughout the olfactory pathway. 2,6-Nonadienal significantly enhanced olfactory responses, but had no significant effect on output behavior. Thesefindings provide foundations in utilization of plant volatiles and sex pheromones to manage the pest and otheragricultural pests.

중국 대학의 학생자율모집제도 연구

김예선 ( Jin Rui Xian ),고장완 ( Ko Jang Wan ) 인하대학교 교육연구소 2019 교육문화연구 Vol.25 No.3

중국 대학의 학생자율모집정책은 통일적인 대학입학시험을 위주로 한 다원적 시험평가와 다양한 학생선발 방식의 탐색이었으며 2003년 처음으로 실시된 이래로 사회의 광범위한 관심을 받아왔다. 2014년 12월 학생자율모집정책은 전면적인 개혁을 진행하였으며, 2018년까지 총 90개 대학들이 학생자율모집전형을 실시하고 있다. 본 연구는 중국의 학생자율모집정책 개혁 이후의 실행 현황 및 문제점을 파악하기 위해 Cooper 등의 다차원 교육정책분석 모형을 도입하여 규범적 차원, 구조적 차원, 구성적 차원 및 기술적 차원에서 학생자율모집정책을 분석하였다. 규범적 차원에서 중국사회의 변혁과 공평성을 살펴보았고, 구조적 차원에서 정부와 대학의 구조관계 및 정부의 법적 지원제도를 중점적으로 분석하였다. 구성적 차원에서는 대학을 중심으로 하여 대학과 정부, 대학과 고등학교, 대학과 학생 및 학부모 이 세 관계를 집중적으로 다루었으며, 마지막으로 기술적 차원에서는 개혁 전후 치열한 논쟁이 이루어진 신뢰성 및 전문성을 중점적으로 분석하였다. 본 연구 결과를 바탕으로 중국의 실정에 맞는 학생자율모집정책의 향후 발전방향을 제언하였다. Since China restored the policy of College Entrance Examination, the Chinese government has made continuous adjustments and reforms in accordance with the demands of social development. The policy of autonomous enrollment focused on improving the College Entrance Examination system and exploring multiple evaluation and selection methods of students. It has gained wide attention in academia and community since it has been introduced. The reform of Chinese autonomous enrollment was deepened in 2014, and a total of 90 universities have been authorized to implement this policy by 2018. The purpose of this study was to analyze the implementation of the autonomous enrollment policy reform and the current problems by adopting Cooper’s four-dimensional educational policy analysis model. For this purpose, this dissertation examined Chinese social transition and education equity from the normative dimension. And then it analyzed the structural relationship between the government and universities, as well as the legal support system of the government from the structural dimension. From the constituentive dimension, this paper observed three interest group relationships dominated by universities: universities and the government, universities and high schools, as well as universities and students with their parents. Lastly, this paper focused on the reliability and professionalism of examination which have been fiercely debated before and after the reform. Based on the result of the analysis, this paper finally explored the future direction of Chinese Autonomous Enrollment Policy.