Active Power Filter Using Nonlinear Repetitive Controller

Xin Tang,Kai Ming Tsang,Wai Lok Chan 제어·로봇·시스템학회 2011 International Journal of Control, Automation, and Vol.9 No.1

Active power filters as solutions to power quality problems have become more and more important nowadays. A nonlinear repetitive controller for current control of active power filters is proposed. The proposed method is composed of a repetitive controller and a deadband relay. Whenever the input error is above the threshold, the current control loop is driven dominantly by the deadband relay to obtain fast dynamic response. After the input error is below the threshold, the deadband relay automatically turns off and the repetitive control alone governs the current control to eliminate the steady-state error. Discussions on the design of the current and voltage control loops are also given. Simulation and experimental results verified the feasibility of the proposed method.

A highly efficient catalyst for direct synthesis of methyl acrylate via methoxycarbonylation of acetylene

Cong-Ming Tang,Xin-Li Li,Gong-Ying Wang 한국화학공학회 2012 Korean Journal of Chemical Engineering Vol.29 No.12

A non-petroleum approach for the catalytic synthesis of methyl acrylate via methoxycarbonylation of acetylene with carbon monoxide and methanol as nucleophilic reagent has been studied under various conditions. Pd(OAc)2/2-PyPPh2/p-tsa was found to be a highly efficient catalytic system. The types of phosphorus ligands and their concentration was a determinative factor for catalytic activity. Mono-dentate phosphorus ligand such as triphenylphosphine has no activity while 2-(diphenylphosphino)pyridine with a mixed N-P bidentate structure has an excellent activity. Catalytic performance of acids depends on their acidic strength and coordinative property. Among all acidic promoters, p-toluenesulfonic acid displayed an excellent performance. Other parameters such as solvent polarity and initial pressure of carbon monoxide have also important influences on the hydroesterification of acetylene. It is beneficial for the reaction that the solvents have a high polarity. At low pressure of carbon monoxide, to high active palladium catalyst, the reaction easily proceeded. However, at high pressure of carbon monoxide, acetylene will transfer from solution to gas phase,resulting in lower conversion of acetylene. In addition, due to steric hindrance of alcohols, methanol has a highest activity in hydroesterification of acetylene in low carbon alcohols. Under the optimal reaction conditions, 99.5% of acetylene conversion and 99.7% of selectivity toward methyl acrylate as well as 2,502 h−1 TOF were achieved.

Sustainable production of acetaldehyde from lactic acid over the carbon catalysts

Cong-Ming Tang,Jiansheng Peng,Xin-Li Li,Zhanjie Zhai,Hejun Gao,Wei Bai,Ning Jiang,Yunwen Liao 한국화학공학회 2016 Korean Journal of Chemical Engineering Vol.33 No.1

The synthesis of acetaldehyde from lactic acid over the carbon material catalysts was investigated. The carbon materials were characterized by scanning electron microscopy for morphologic features, by X-ray diffraction for crystal phases, by Fourier transform infrared spectroscopy for functional group structures, by N2 sorption for specific surface area and by ammonia temperature-programed desorption for acidity, respectively. Among the tested carbon catalysts, mesoporous carbon displayed the most excellent catalytic performance. By acidity analysis, the medium acidity is a crucial factor for catalytic performance: more medium acidity favored the formation of acetaldehyde from lactic acid. To verify, we compared the catalytic performance of fresh activated carbon with that of the activated carbon treated by nitric acid. Similarly, the modified activated carbon also displayed better activity due to a drastic increase of medium acidity amount. However, in contrast to fresh carbon nanotube, the treated sample displayed worse activity due to decrease of medium acidity amount. The effect of reaction temperature and time on stream on the catalytic performance was also investigated. Under the optimal reaction conditions, 100% lactic acid conversion and 91.6% acetaldehyde selectivity were achieved over the mesoporous carbon catalyst.

Separative capability of γ-Al2O3 porous ceramic membrane modified by ZIF-8

Cong-Ming Tang,Xin-Li Li 한국화학공학회 2013 Korean Journal of Chemical Engineering Vol.30 No.5

Several precursors such as zinc nitrite, zinc chloride, zinc acetate and zinc sulfate were used to synthesize ZIF-8. These zeolitic imidazolate frameworks synthesized from different zinc precursors under different reaction conditions were characterized by XRD, SEM and FTIR. The synthesis of ZIF-8 was not sensitive to zinc precursor and reaction parameter. Subsequently, we used ZIF-8 to modify the γ-Al2O3 porous ceramic membrane, expecting improvement of separation performance in the γ-Al2O3 porous ceramic membrane. The experimental results indicated that the permselectivity of hydrogen/nitrogen was enhanced in the γ-Al2O3 porous ceramic membrane modified with ZIF-8,although the gas permeance through the modified membrane slightly decreased. In addition, the modified γ-Al2O3 porous ceramic membrane was used to separate the binary systems containing ethanol-water and acrylic acid-water. The separation factor of ethanol to water is 3.1, while it is 2.6 as for acrylic acid-water. Furthermore, the permeance in the former is about five times than that of the latter.

The complete mitochondrial genome of fall armyworm Spodoptera frugiperda (Lepidoptera:Noctuidae)

Bo-Ping Tang,Qiu-Ning Liu,Xin-Yue Chai,Dan-Dan Bian,Bao-Ming Ge,Chun-Lin Zhou 한국유전학회 2016 Genes & Genomics Vol.38 No.2

The mitochondrial genome (mitogenome) can provide important information for understanding molecular evolution and phylogenetic analyses. The complete mitogenome of Spodoptera frugiperda (Lepidoptera:Noctuidae) was determined to be 15,365 bp in length and has the typical gene order found in Noctuidae mitogenomes, it includes 13 protein-coding genes (PCGs), two rRNA genes, 22 tRNA genes and a A?T-rich region. The nucleotide composition was biased toward A?T nucleotides (81.09 %) and the AT skew of this mitogenome was slightly positive (0.004). All PCGs were initiated by ATN codons, except for cytochrome c oxidase subunit 1 (cox1) gene which was initiated by CGA. Eight of the 13 PCGs have the incomplete termination codon, T or TA. All the tRNA genes displayed the typical clover-leaf structure of mitochondrial tRNAs, with the exception of trnS1 (AGN). The A?T-rich region was 328 bp in length and consisted of several features common to the Noctuidae insects. Phylogenetic analysis showed that the S. frugiperda was within the Noctuidae.

A new absorbing foam concrete: preparation and microwave absorbing properties

Xingjun, Lv,Mingli, Cao,Yan, Li,Xin, Li,Qian, Li,Rong, Tang,Qi, Wang,Yuping, Duan Techno-Press 2015 Advances in concrete construction Vol.3 No.2

The foam concrete was fabricated by adding the foaming agent which composite ordinary Portland cement with plant and animal protein into cement paste, and the electromagnetic wave absorption properties were studied for the first time as well. The studies showed that the electromagnetic waves can be absorbed by multiple reflections and scattering within the porous material. Thickness and filling ratio have a great influence on the electromagnetic wave absorbing properties in 2-18 GHz of the foam concrete, the greater the thickness, the better the performance of absorption; filling ratio was about 52 vol.%, the absorbing properties achieved the best.

The Implementation of Sanitary Ware Subsequent Water Simulation Test System

Chu Yan,Cai Xin-yuan,Feng Xiao-ming,Tang Kang,Sun Nai-hua 보안공학연구지원센터 2014 International Journal of Control and Automation Vol.7 No.7

Clinical Effectiveness of Preoperative Embolization for Cerebellar Hemangioblastoma

Liu, Ai-Hua,Peng, Tang-Ming,Wu, Zhen,Xiao, Xin-Ru,Jiang, Chu-Han,Wu, Zhong-Xue,Li, You-Xiang Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.9

The cerebellar hemangioblastoma (CHB) has an abundant blood supply and deep anatomical location. Complete surgical resection is generally very difficult. This study investigated the safety and effectiveness of preoperative embolization followed by surgical resection of CHB in a large cohort of patients. A database of 125 CHB patients with surgical resection in Beijing Tiantan Hospital between July 2006 and July 2012 was reviewed. Of those, 46 cases (experimental group) received preoperative embolization, 79 cases (control group) underwent surgery without embolization. Patient demographics, tumor size, duration of surgery, blood loss, blood transfusion, complications and follow-up results were collected and analyzed retrospectively. In the experimental group, the Kamofsky score (KS) was 80-100 in 40 cases (86.9%), 40-70 in 4 cases (8.7%), and below 40 in 2 cases (4.3%). Among 31 cases with follow-up, KS was 80-100 in 27 cases (87.1%), 40-70 in 2 cases (6.5%), and 0 in 2 cases (6.5%). In control group, KS was 80 -100 in 65 cases (82.2%), 40-70 in 6 cases (7.6%), 10-30 in 3 cases (3.8%), and 0 in 3 cases (3.8%). Among 53 cases with follow-up, KS was 80-100 in 44 cases (83.0%), 40-70 in 4 cases (7.5%), 10-30 in 1 case (1.9%), and 0 in 4 cases (7.5%). There were statistically significant differences between the experimental and control groups in tumor size, duration of surgery, amount of intraoperative blood loss and transfusion (p<0.01). However, complications (p=0.31) and follow-up results (p=0.76) showed no significant differences between groups. Selective preoperative embolization of those CHB patients with richer blood supply, higher hemorrhage risk, is safe and effective, and is a reliable adjuvant therapy for complete surgical resection of CHB.

Importance of Symptomatic Cerebral Infarcts on Cognitive Performance in Patients with Alzheimer’s Disease

조수진,Nikolaos Scarmeas,장태원,Karen Marder,Ming-Xin Tang,Lawrence S. Honig 대한의학회 2011 Journal of Korean medical science Vol.26 No.3

The coexistence of cerebral infarcts and Alzheimer’s disease (AD) is common, but the influence of symptomatic cerebral infarcts on cognition is uncertain in AD. We hypothesize that symptomatic cerebral infarcts may provide an additive cognitive factor contributing to dementia in the AD population. We studied 1,001 clinically probable or possible AD patients in the Alzheimer Disease Research Center (ADRC) database. Linear regression was used to evaluate for an association between symptomatic cerebral infarcts and memory,language, executive function, abstract reasoning, and visuospatial performance,separately. Models were adjusted for covariates including age, gender, education,ethnicity, hypertension, diabetes mellitus, heart disease, clinical dementia rating, the presence of silent cerebral infarcts, and multiplicity or location of infarcts. Clinical history of stroke was present in 107 patients, radiological infarcts in 308 patients, and 68 patients with both were considered to have symptomatic infarcts. Adjusting for all covariates, AD patients with symptomatic infarcts had more impairment of executive function (P < 0.05). The influence of cerebral infarcts is neither general nor diffuse, and the presence of clinical history may have a more important influence on executive performance in AD.

Load and Mutual Inductance Identification Method for Series-Parallel Compensated IPT Systems

Long Chen,Yu-Gang Su,Yu-Ming Zhao,Chun-Sen Tang,Xin Dai 전력전자학회 2017 JOURNAL OF POWER ELECTRONICS Vol.17 No.6

Identifying the load and mutual inductance is essential for improving the power transfer capability and power transfer efficiency of Inductive Power Transfer (IPT) systems. In this paper, a steady-state load and mutual inductance identification method focusing on series-parallel compensated IPT systems is proposed. The identification model is established according to the steady-state characteristics of the system. Furthermore, two sets of identification results are obtained, and then they are analyzed in detail to eliminate the untrue one. In addition, the identification method can be achieved without extra circuits so that it does not increase the complexity of the system or the control difficulty. Finally, the feasibility of the proposed method has been verified by simulation and experimental results.