The effect of aeration mode on the operational effectiveness and membrane bioreactors for greywater treatment and membrane fouling

Chunhong Shi,Bo Yan,Xiangmeng Zuo,Cheng Wang,Zifu Li,Lixin Zhu 대한환경공학회 2023 Environmental Engineering Research Vol.28 No.2

This study aims to investigated the effect of aeration mode on membrane bioreactors (MBRs) using a self-designed integrated hollow fiber MBR and flat sheet organic MBR for rural greywater treatment. The pollutant removal efficiency, characteristics of activated sludge and mixed liquor, and mechanisms of membrane fouling were systematically analyzed under intermittent aeration and continuous modes. The results indicate that the permeability of MBRs in intermittent aeration mode is higher than that in the continuous aeration mode when operating at the same aeration rate. Due to the higher extracellular polymeric substance (EPS) and soluble microbial product (SMP) concentrations. The removal rates of TN and TP by both MBRs at the intermittent aeration mode were higher than those in the continuous aeration mode due to the difference in the aeration environment. Compared to the flat-sheet organic membrane, the hollow-fiber membrane surface was more likely to form biofilms, which cause biological fouling.The relative abundance of Thermomonas showed a positive correlation with the EPS concentration, indicating that Thermomonas participates in EPS synthesis. This study provides a theoretical basis for evaluating the influence of aeration modes on MBRs,and would be a useful guide for the better control of membrane fouling and treatment of rural greywater.

Integral Sliding Mode Control Based on Command Filtering Backstepping for Dual-motor Servo Systems with Torque Disturbance

Chunhong Jin,Baofang Wang,Mingjie Cai 제어·로봇·시스템학회 2023 International Journal of Control, Automation, and Vol.21 No.6

In order to mitigate the influence of the torque disturbance and improve the tracking performance of the dual-motor servo system, this paper designs a controller by combining adaptive command filtering backstepping (CFB) and integral sliding mode control (ISMC). First of all, CFB is utilized to overcome the “explosion of complexity” problem from the traditional backstepping method. And the error compensation mechanism is designed for reducing the filtering errors. Meanwhile, the integral items are designed in the sliding mode surfaces which are novel functions of compensated tracking errors for suppressing the steady-state error, improving the tracking precision. The signum functions are replaced by the saturation functions in switching control laws, which reduces the chattering phenomenon. In addition, synchronization feedback signals are designed in the virtual control laws to ensure the synchronization performance between two motors. The total actual control law is derived, and the system stability as well as state convergence is proved by employing Lyapunov theory. In the end, the simulation research is carried out and the results show the advantage of the proposed control strategy. In order to mitigate the influence of the torque disturbance and improve the tracking performance of the dual-motor servo system, this paper designs a controller by combining adaptive command filtering backstepping (CFB) and integral sliding mode control (ISMC). First of all, CFB is utilized to overcome the “explosion of complexity” problem from the traditional backstepping method. And the error compensation mechanism is designedfor reducing the filtering errors. Meanwhile, the integral items are designed in the sliding mode surfaces which are novel functions of compensated tracking errors for suppressing the steady-state error, improving the trackingprecision. The signum functions are replaced by the saturation functions in switching control laws, which reduces the chattering phenomenon. In addition, synchronization feedback signals are designed in the virtual control lawsto ensure the synchronization performance between two motors. The total actual control law is derived, and the system stability as well as state convergence is proved by employing Lyapunov theory. In the end, the simulationresearch is carried out and the results show the advantage of the proposed control strategy.

The Changes of Proteomes Components of Helicobacter pylori in Response to Acid Stress without Urea

Chunhong Shao,Qunye Zhang,Wei Tang,Wei Qu,Yabin Zhou,Yundong Sun,Han Yu,Jihui Jia 한국미생물학회 2008 The journal of microbiology Vol.46 No.3

Acid stress is the most obvious challenge Helicobacter pylori encounters in human stomach. The urease system is the basic process used to maintain periplasmic and cytoplasmic pH near neutrality when H. pylori is exposed to acidic condition. However, since the urea concentration in gastric juice is approximately 1 mM, considered possibly insufficient to ensure the survival of H. pylori, it is postulated that additional mechanisms of pH homeostasis may contribute to the acid adaptation in H. pylori. In order to identify the acid-related proteins other than the urease system we have compared the proteome profiles of H. pylori strain 26695 exposed to different levels of external pH (7.4, 6.0, 5.0, 4.0, 3.0, and 2.0) for 30 min in the absence of urea using 2-DE. Differentially expressed proteins were identified by MALDI-TOF-TOF-MS analysis, which turned out to be 36 different proteins. The functions of these proteins included ammonia production, molecular chaperones, energy metabolism, cell envelope, response regulator and some proteins with unknown function. SOM analysis indicated that H. pylori responds to acid stress through multi-mechanisms involving many proteins, which depend on the levels of acidity the cells encounter.

Hyperplane distance neighbor clustering based on local discriminant analysis for complex chemical processes monitoring

Chunhong Lu,Xiaofeng Gu,Shaoqing Xiao 한국화학공학회 2014 Korean Journal of Chemical Engineering Vol.31 No.11

The collected training data often include both normal and faulty samples for complex chemical processes. However, some monitoring methods, such as partial least squares (PLS), principal component analysis (PCA), indepen-dent component analysis (ICA) and Fisher discriminant analysis (FDA), require fault-free data to build the normal op-eration model. These techniques are applicable after the preliminary step of data clustering is applied. We here proposea novel hyperplane distance neighbor clustering (HDNC) based on the local discriminant analysis (LDA) for chemicalprocess monitoring. First, faulty samples are separated from normal ones using the HDNC method. Then, the optimalsubspace for fault detection and classification can be obtained using the LDA approach. The proposed method takesthe multimodality within the faulty data into account, and thus improves the capability of process monitoring signifi-cantly. The HDNC-LDA monitoring approach is applied to two simulation processes and then compared with the con-ventional FDA based on the K-nearest neighbor (KNN-FDA) method. The results obtained in two different scenariosdemonstrate the superiority of the HDNC-LDA approach in terms of fault detection and classification accuracy.

The Nuclear Techniques and the Selection of Model Parameters in Big Data

Wang Chunhong 보안공학연구지원센터 2014 International Journal of Database Theory and Appli Vol.7 No.6

Now a large scale of data every day, the large-scale data is usually in the form of database storage. The law of the people wants to find useful or knowledge, thus was born the Data Mining technology. SVM (Support Vector Machine, SVM) is a very useful method in data mining, this paper mainly discusses the Support Vector Machine (SVM) play a key role in nuclear techniques and the selection of model parameters is analyzed and evaluated. This article some methods about how to construct the kernel function is introduced for the model to find suitable kernel function is to provide some reference strategies and proposed kernel function method for the simulation analysis.

大学英语教学中的道德教育与品格塑造

蒲春红(Chunhong Pu) YIXIN 출판사 2023 教育教学研究论丛 Vol.1 No.3

영국의 공립학교 구조 개혁 : 아카데미의 자율성, 책무성, 협력적 거버넌스 측면에서

김천홍 ( Chunhong Kim ),홍수진 ( Sujin Hong ) 충남대학교 교육연구소 2017 교육연구논총 Vol.38 No.1

본 연구의 목적은 영국 공립학교의 아카데미 전환 정책의 배경, 내용, 특징 및 주요 쟁점을 분석하여 학교 구조 개혁에 대한 시사점을 도출하는 것이다. 아카데미는 학력 저하 학교들의 성취 수준 향상을 위해 도입된 자율형 공립학교로서, 2022년까지 모든 초·중등 공립학교를 아카데미로 전환할 것을 공표한 후 다양한 논쟁이 진행 중이다. 분석 결과 영국의 아카데미 정책은 첫째, 국가수준의 학교 구조 개혁을 통해 교육 제 영역에 대한 혁신을 통합적으로 접근하는 특징이 확인되었다. 둘째, 학교 교육과정 편성·운영, 교육 재원의 사용, 교원 선발과 급여 수준 결정 등에 대한 단위학교의 자율성을 폭넓게 부여하고 있다. 셋째, 아카데미는 내적 책무성과 성과주의 학교 책무성 체제 간의 제도적 긴장 관계를 형성하고 있다. 넷째, 아카데미는 다양한 거버넌스를 구축하여 학교 간 협력 강화를 학교 발전의 핵심적 원리로 적용하고 있다. 본 연구의 분석 결과를 바탕으로 공교육 개혁을 위해서는 학교 구조 개혁의 필요성을 강조하고, 단위학교의 자율성 강화는 학교 및 교사의 자율적 교육 활동 실천을 위한 역량과 균형을 이룰 수 있는 제도적 지원 방안이 중요함을 제언하였다. 끝으로 단위학교의 자율성에 비례하는 명확한 학교 책무성 체제 구축과 함께 학교 간 협력적 네트워크 강화와 질 관리를 위한 방안을 논의하였다. The purpose of this study is to analyze school reforms whereby which all maintained schools will convert to academies by 2022 in England. Although converting maintained schools to academies, the flagship education policy for educational reform in England, has significant theoretical and practical implications, research on academy policy remains an under-explored area, and there is a noticeable lack of research exploring the background, key characteristics, impacts on educational effectiveness and improvement from a comparative perspective. The major findings show that the model of academization focuses on the educational structure to foster school innovation through school collaborative partnerships. The policy also emphasizes that school autonomy regarding curriculums, school management, initial teacher training and professional development is the driving force for school improvement. The academization model shares the feature of vertical and horizontal school accountability system. However it is apparently to enhance vertical aspect of accountability, resulting in the institutional tension between two different type of school accountability. Finally it is found that school-to-school collaborative governance is the underpinning principle of academization as the effective means in supporting underperforming schools. Based on the results, this study reflects on a number of issues related with the academization of maintained schools and suggests implications for school reform in terms of school autonomy, accountability, and collaborative governance.

Synergistic effect of novel ionic liquid/graphene complex on the flame retardancy of epoxy nanocomposites

Zhang Chunhong,Xu Zice,Sui Wenbo,Zang Junbo,Ao Yuhui,Wang Lu,Shang Lei 한국탄소학회 2023 Carbon Letters Vol.33 No.2

Epoxy resin (EP) is a thermosetting resin with excellent properties, but its application is limited due to its high brittleness and poor flame retardancy. Therefore, to solve this problem, a dispersion system of imidazole-containing ionic liquid ([Dmim]Es) and graphene in epoxy resin is designed based on the π–π stacking effect between imidazole and graphite layers. The study on the thermal and flame-retardant properties of the composites show that the modified [Dmim]Es–graphene nanosheets improved the flame retardancy, smoke suppression and thermal stability of epoxy resin. With the addition of 5wt% [Dmim]Es and 1% Gra, the exothermic rate (HRR) and total exothermic (THR) of the composites decrease by 35% and 30.2% compared with the untreated epoxy cross-linking, respectively. The limiting oxygen index reaches 33.4%, the UL-94 test rating reaches V-0. The characterization of mechanical properties shows that the tensile properties and impact properties increased by 13% and 30%, respectively. Through SEM observation, the addition of [Dmim]Es improves the dispersion of graphene in the EP collective and changes the mechanical fracture behavior. The results show that ionic liquid [Dmim]Es-modified graphene nanosheets are well dispersed in the matrix, which not only improves the mechanical properties of epoxy resin (EP), but also has a synergistic effect on flame retardancy. This work provides novel flame-retardant and graphene dispersion methods that broaden the range of applications of epoxy resins.

영국 통제수행평가 체제 분석 및 적용가능성 탐색

김천홍(Kim, ChunHong),홍수진(Hong, SuJin) 학습자중심교과교육학회 2017 학습자중심교과교육연구 Vol.17 No.23

본 연구는 영국의 표준화된 고부담 수행평가인 통제수행평가의 체제를 분석하여 한국의 수행평가에 대한 시사점을 도출하는 것을 목적으로 한다. 이를 위해 통제수행평가의 평가내적 영역과 외적 영역 측면에서 내용과 특성을 분석하였다. 분석 결과 첫째, 통제수행평가는 영국자격시험감독청, 외부 인증평가기관, 단위학교 간 수직적 감독과 수평적 협력의 거버넌스 체제로 운영되고 있다. 둘째, 통제수행평가는 교과의 특성과 측정 영역에 따른 다양한 평가 도구를 활용한다. 셋째, 통제수행평가의 평가절차는 과제 설정, 과제 수행, 과제 채점의 3단계로 구성되어 있으며 각 평가 단계별로 차별적인 통제수준을 적용하여 수행평가의 객관성과 타당성을 확보한다. 넷째, 통제수행평가는 교사 채점과 외부 채점조정관의 채점 결과 간의 상관관계를 비교하여 조정한 후 중등교육자격 수여 및 대입전형 자료로 활용된다. 이러한 분석 결과를 바탕으로 통제수행평가의 한국에서의 적용 가능성을 수행평가의 확대 적용 측면, 평가의 객관성 및 공정성 측면, 교사의 평가 업무 부담의 가중 측면, 대규모 고부담 평가에서의 채점 절차 측면, 사교육과 같은 학교 외적 요인의 영향 측면에서 논의 하였다. 영국 통제수행평가에 대한 분석 결과와 한국에의 적용 가능성에 대한 비판적 논의를 확장하여 수행평가 영역별, 교육 주체별 실천 방안을 단기, 중기, 장기적 관점에서 제시하고 수행평가의 타당성을 확보하기 위한 방안을 제언하였다. The purpose of this study is to analyze controlled assessment in GCSEs and then explore the applicability of it to performance assessment in Republic of Korea. Adapting a content analysis with related documents issued by the Ofqual, Ofsted, QCA, awarding body in England, this study scrutinizes the governance, the procedure, the use of result, the quality assurance, the cultural aspect of controlled assessment. The major findings show that firstly, controlled assessment is governed by the tripartite system, which allocates the responsibility and delegates authority to Ofqual, awarding body and school with vertical accountability and horizontal collaboration. Secondly, controlled assessment consists of three stages: task setting, task taking and task marking. The level of control at each of three key stages falls into one of three categories: limited-, medium- and high control. Thirdly, the weighting of controlled assessment result is one of three defined ratios, which reflect the characteristic of the assessed subjects. Lastly, for the purpose of keeping the consistent standard of marking, the original assessed marks by teachers are either accepted without any change or adjusted through the moderation process conducted by the external moderator. Based on the analysis of controlled assessment, this study explores the possibility and feasibility of applying the main principle and feature of controlled assessment to carrying performance assessment in Republic of Korea. To do so, this study critically takes the Korean educational contexts and assessment policy aims into account, such as enlarging performance assessment, enhancing validity, reliability and transparency of it, reducing teachers’ assessment burdens, and restraining the effect of private education.

백내장 시각적 특성을 고려한 지하철 공공사인의 컬러유니버설디자인 현황분석 - 중국 청두와 충칭을 대상으로

오춘굉(Wu, ChunHong),이석현(Lee, SeokHyun) 한국색채학회 2021 한국색채학회 논문집 Vol.35 No.4

For most cities in China, there is no sign color guideline of public spaces for aging cataract user. However, the color of public sign design considering the increasing number of elderly people is important in creating a pleasant mobile environment for users. Based on the universal design, this research explored the visual characteristics, and conducted field investigation and analysis of the major subway transfer stations such as Chengdu and Chongqing, which are representative cities in southwestern China. And this paper is to provide suggestion for the improvement methods of sign color guideline on the city’s public spaces. According to the visual characteristics of cataract and the requirements of general design, the Munsell color system was directly used to measure the color of Chengdu and Chongqing subway stations. Taking the difference in brightness between adjacent colors in the readability difference of 6 and above as the standard, this study found that Chengdu accounts for 5% of the total, and Chongqing accounts for 46%, which is significantly higher than Chengdu. According to the color readability of the adjacent color senile cataract as the standard of contrast color, the survey results show that the image color and background color of Chengdu and Chongqing are all black, white, gray and other colors. There is no contrast between colors, but gray contrast with other colors as well as the contrast between black and white. Based on the survey and analysis of representative subway station in china cities, we suggest the sign color guide of public space for aging cataract user.