New Method of Designing Controller for Uncertain Diff erential-Diff erence Systems and Application to Time-Delay Operational Amplifi er System

Ke Jian,Chung-Cheng Chen,Yen-Ting Chen,Gui-hong Lin 대한전기학회 2020 Journal of Electrical Engineering & Technology Vol.15 No.6

This study combines the feedback linearization method and our recent researches of Chen electrical unifying approach to propose a global tracking controller design for nonlinear uncertain diff erential-diff erence systems with time delay. One example, which cannot be solved by the fi rst paper on the almost disturbance decoupling problem, is presented in this study to show the essential points that the tracking performance is easily solved by the proposed approach. The study applies Chen electrical unifying approach to take the place of using the disorganized virtual ground technique and the Kirchhoff ’s law for those traditional approaches. In order to show its signifi cant practicability, the study has fi rstly designed an easy-to-implement adder and a time-delay circuit, and an unstable time-delay operational amplifi er control system based on the Chen electrical unifying approach, and then has proposed a stable controller.

Experimental study on cold-formed lipped channel stub columns reinforced by steel bars or steel strips

Jian-Feng Chen,Ming-Qi Chen,Yong-Kang Shen,Jian-Hua Shao,Xin-Xin Yang 국제구조공학회 2021 Steel and Composite Structures, An International J Vol.40 No.3

In this paper, the axial compressive properties of cold-formed steel lipped channel stub columns strengthened by rebars or steel strips are experimentally studied. The experiment included two sections. A kind of columns with local buckling is reinforced longitudinally by steel strips at the web. The other is the columns with distorted buckling, which is reinforced longitudinally by steel bars at the curling edge. The failure mode, deformation characteristics, ultimate bearing capacity and load displacement curve of the specimen are obtained through the experiment. On the basis of the experiment, the calculation results of theoretical axial bearing capacity of cold-formed steel lipped channel stub columns in Chinese, North American and Australian code are compared and analyzed. Research indicates: First, the cold-formed steel lipped channel stub columns strengthened by steel bars or steel strips can effectively improve the compressive bearing capacity of the specimen. Secondly, when the initial stress ratio of specimen is less than 0.3, the reinforcement effect is ideal. Thirdly, the three standards don’t stipulate the calculation of theoretical bearing capacity of the specimen strengthened after loading, so there is a large deviation between the theoretical calculation value and the test value.

Kinetics of Nitrogen Absorption in Molten AISI 316 Stainless Steel During Immersion Nitrogen Blowing

Chen Jian-Bin,Chen Qi-Zhong,Chen Zhao-Ping,Jiang Zhou-Hua,Huang Zong-Ze,Pan Jia-Qi 대한금속·재료학회 2012 METALS AND MATERIALS International Vol.18 No.1

Nitrogen absorption in molten metal for stainless steel AISI316 has been investigated by immersion nitrogen blowing through an immersed alumina nozzle with an internal diameter of 3 mm. Based on these experimental data, some kinetic parameters of nitrogen absorption, such as reaction order, rate constant and apparent activation energy of nitrogen absorption reaction, have been obtained. Effect of stirring by immersion nitrogen blowing through an immersed alumina nozzle on nitrogen absorption reaction has been observed. Results show the following: (1) Nitrogen absorption reaction is the −1.5th order reaction. The rate constant N is of the order of 10−5wt%2.5·min −1. Nitrogen absorption reaction for AISI 316 has negative apparent activation energy of −92.40 kJ·mol −1. This indicates that the nitrogen absorption reaction has a complex and multistep reaction mechanism. (2) The rate of nitrogen absorption reaction in molten stainless steel is mixture control by the adsorption of monatomic nitrogen on the surface of molten stainless steel and mass transfer in molten metal. (3) A rate equation of nitrogen absorption reaction has been derived based on a mixed control mechanism by both the -1st order nitrogen absorption reaction and mass transfer in molten metal.

Listeria monocytogenes Serovar 4a is a Possible Evolutionary Intermediate Between L. monocytogenes Serovars 1/2a and 4b and L. innocua

Jian Shun Chen,Ling Li Jiang,Xue Yan Chen,Xiao Kai Luo,Yang Chen,Ying Yu,Guo Ming Tian,Dong You Liu,Wei Huan Fang 한국미생물 · 생명공학회 2009 Journal of microbiology and biotechnology Vol.19 No.3

Long Term Outcomes and Prognostic Factors of N₀ Stage Nasopharyngeal Carcinoma: a Single Institutional Experience with 610 Patients

Sun, Jian-Da,Chen, Chuang-Zhen,Chen, Jian-Zhou,Li, Dong-Sheng,Chen, Zhi-Jian,Zhou, Ming-Zhen,Li, De-Rui Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.5

Treatment responses of $N_0$ stage nasopharyngeal carcinoma were firstly analyzed comprehensively to evaluate long term outcomes of patients and identify prognostic factors. A total of 610 patients with $N_0$ NPC, undergoing definitive radiotherapy to their primary lesion and prophylactic radiation to upper neck, were reviewed retrospectively. Concomitant chemotherapy was administrated to 65 out of the 610. Survival rates of the patients were calculated using the Kaplan-Meier method and compared by log-rank test. Prognostic factors were identified by the Cox regression model. The study revealed the 5-year and 10-year overall, disease-free, disease-specific, local failure-free, regional failure-free, locoregional failure-free and distant metastasis-free survival rates to be 78.7% and 66.8%, 68.8% and 55.8%, 79.9% and 70.4%, 81.2% and 72.5%, 95.8% and 91.8%, 78.3% and 68.5%, 88.5% and 85.5%, respectively. There were 192 patients experiencing failure (31.5%) after radiotherapy or chemoradiotherapy. Of these, local recurrence, regional relapse and distant metastases as the first event of failure occurred in 100 (100/610, 16.4%), 15(15/610, 2.5%) and 52 (52/610, 8.5%), respectively. Multivariate analysis showed that T stage was the only independent prognostic factor for patients with $N_0$ NPC (P=0.000). Late T stage (P=0.000), male (P=0.039) and anemia (P=0.007) were independently unfavorable factors predicting disease-free survival. After treatment, satisfactory outcome wasgenerally achieved in patients with $N_0$ NPC. Local recurrence represented the predominant mode of treatment failure, while T stage was the only independent prognostic factor for overall survival. Late T stage, male gender, and anemia independently predicted lower possibility of the disease-free survival.

miR-340 Reverses Cisplatin Resistance of Hepatocellular Carcinoma Cell Lines by Targeting Nrf2-dependent Antioxidant Pathway

Shi, Liang,Chen, Zhan-Guo,Wu, Li-li,Zheng, Jian-Jian,Yang, Jian-Rong,Chen, Xiao-Fei,Chen, Zeng-Qiang,Liu, Cun-Li,Chi, Sheng-Ying,Zheng, Jia-Ying,Huang, Hai-Xia,Lin, Xiang-Yang,Zheng, Fang Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.23

Many chemotherapeutic agents have been successfully used to treat hepatocellular carcinoma (HCC); however, the development of chemoresistance in liver cancer cells usually results in a relapse and worsening of prognosis. It has been demonstrated that DNA methylation and histone modification play crucial roles in chemotherapy resistance. Currently, extensive research has shown that there is another potential mechanism of gene expression control, which is mediated through the function of short noncoding RNAs, especially for microRNAs (miRNAs), but little is known about their roles in cancer cell drug resistance. In present study, by taking advantage of miRNA effects on the resistance of human hepatocellular carcinoma cells line to cisplatin, it has been demonstrated that miR-340 were significantly downregulated whereas Nrf2 was upregulated in HepG2/CDDP (cisplatin) cells, compared with parental HepG2 cells. Bioinformatics analysis and luciferase assays of Nrf2-3'-untranslated region-based reporter constructor indicated that Nrf2 was the direct target gene of miR-340, miR-340 mimics suppressing Nrf2-dependent antioxidant pathway and enhancing the sensitivity of HepG2/CDDP cells to cisplatin. Interestingly, transfection with miR-340 mimics combined with miR-340 inhibitors reactivated the Nrf2 related pathway and restored the resistance of HepG2/CDDP cells to CDDP. Collectively, the results first suggested that lower expression of miR-340 is involved in the development of CDDP resistance in hepatocellular carcinoma cell line, at least partly due to regulating Nrf2-dependent antioxidant pathway.

PERCEIVED RESIDENTIAL ENVIRONMENT QUALITY, PLACE ATTACHMENT, AND ENVIRONMENTAL SATISFACTION: THE COMPETING MODELS IN RURAL AND URBAN AREAS OF CHINA

Kangkang Yu,Ning (Chris) Chen,Xinkai Zhu,Jian Gao 글로벌지식마케팅경영학회 2016 Global Marketing Conference Vol.2016 No.7

Level of urbanization in China has reached 53.73% in 2013, indicating a tremendous progress on the urbanization of China. On the other hand, the number of villages in China reduces by around one million from 3.6 million in 2000 to 2.7 million in 2010 (Zhang, 2014). Issues in both urban and rural areas of China appear, including the imbalance between increased population and limited resources in urban region, and more significantly, the increasing disparity between rural and urban areas. Chinese researchers interpret and analyse these matters from different perspectives. For instance, Zheng (2006) and Ma (2006) suggest the importance of the infrastructure construction and public service. Wu (2006) advises that the government should pay attention to the development of the secondary and tertiary industry. Wen (2005) proposes that the improvement of social institution and the recovery of social cultural environment are required to achieve sustainability in the urbanization process in China. Previous studies in environmental psychology put quality of life, attachment to place, and residence satisfaction at the center to understand the relationship between inhabitants and their neighborhood of residence. However, there are gaps in this research realm in both practice and theories. Firstly, very limited research studies this environmental psychology issue in China (e.g. Mao, Fornara, Manca, Bonnes, & Bonaiuto, 2015). Secondly, there are different opinions on the causal order between quality, attachment, and satisfaction. Research on the relationship between perceived residential environment quality (PREQ), place attachment, and environmental satisfaction has not reached a consensus. The debate on the direction of the causal relationship between perceived quality and satisfaction has been summarized by Bradya and Robertson (2001). They conclude that the quality to satisfaction causal order holds up well across diverse cultures. However, relevant debate is still ongoing. A number of research articles place satisfaction as an antecedent to attachment, e.g. Chen, Dwyer, and Firth (2014); Lee, Kyle, and Scott (2012); Ramkissoon and Mavondo (2015); etc. Some argue that place attachment is an indicator of satisfaction. Kyle et al. (2004) investigate the effect of place attachment on the perceived values of tourists and find that place attachment is an important factor explaining the variance of perceived values. This is supported by research e.g. Hwang, Lee, and Chen (2005); Prayag and Ryan (2012); Yuksel, Yuksel, Biljm (2010); etc. As to the relationship between perceived quality and attachment, the debate has not stopped. Through comparisons, Mesch and Manor (1996) conclude that the residents who give a higher evaluation of the social and natural environment may have greater place attachment. Brown, Perkins, and Brown (2003) also suggest that the residents who agree that the street environment is better would attach to this place. Sam, Bayram, and Bilgel (2012) have certified the relationship between residential environment quality and place attachment. Furthermore, Borrie and Roggenbuck (2001) and Walker and Ryan (2008) find that the connection between human beings and the nature environment would affect their affection toward the environment. It means that the closer the relationship with the nature environment is, the stronger the attachment would be, which in turn, enhances the intentions to protect the environment. This quality to satisfaction relationship is supported by other research such as Bonaiuto, Aiello, Perugini, Bonnes, and Ercolani (1999); Grisaffe and Nguyen (2011); Yu, Chen, and Chen (2015); etc. Nevertheless, a different opinion arguing that attachment to a place may affect one’s perception on the quality related to a place is emerging in tourism research (e.g. Neuvonen, Pouta, & Siev?nen, 2010). This paper takes the credit of quality → attachment → satisfaction causal order as the initial model and proposes three hypotheses as follows. H1a: One’s PREQ has a positive impact on his/her attachment to this place; H2a: One’s attachment to a place has a positive impact on his/her satisfaction to the environmental settings in this place; H3a: Place attachment in addition performs as a mediating role between PREQ and environment satisfaction.To be noted, the initial model has its theoretical basis as discussed above but is not necessarily the absolute optimal model. Relatively, this model provides more theoretical interpretation and practical implications in the specific research context: residential psychology in urban and rural areas of China. On this basis, this article further examines a competing model illustrating an alternative theoretical framework on the relationships between these three constructs (satisfaction → attachment → quality). Relatively, another group of hypotheses in this competing model is listed as follows. H1b: One’s attachment to a place has a positive impact on his/her PREQ; H2b: One’s satisfaction to the environmental settings in this place has a positive impact on his/her attachment to this place; H3b: Place attachment in addition performs as a mediating role between environment satisfaction and PREQ. A survey approach is employed and data are collected from several backgrounds. Dataset A (rural) is collected from three villages from Heilongjiang Province and two villages from Shandong Province in China from July to August 2014. The choices of the provinces, rural areas, and the sampling process are random. 490 valid questionnaires are included in the data analysis. Dataset B (urban) is collected via an online survey portal, which allows a nationwide sampling reach. In total 1368 online survey entries are recorded and 420 valid questionnaires are included, resulting in a valid rate of 30.7%. The measures for each construct are based on an extensive literature review. The measurement of perceived residential environment quality is from Sam, Bayram, & Bilgel’s (2012) development on the perception of residential environment. The measurement of place attachment in this study is adopted from Kyle, Graefe, and Manning’s (2005) and Chen, Dwyer, and Firth’s (2014) evaluation based place attachment dimensionality and scales. As for the scale of environmental satisfaction, Pelletier, Legault, and Tuson’s (1996) measure was applied. All the entire variables adopted multiple-item, 5-point Likert scales were adopted, where “1” indicated “strongly disagree” and “5” indicated “strongly agree”. After pre-testing the preliminary version of the survey instrument, a revised version was developed. This study adopts structural equation modeling (SEM) based on partial least squares (PLS) modeling given the small sample size and the explorative purpose of this study (Dijkstra & Henseler, 2015a). The software used was Smart PLS 3.0. The reliability and validity of the constructs were assessed. Cronbach’s alpha and the value of CR of each construct were found to exceed the cut-off value of 0.70 (Fornell & Larcker, 1981), except for adequacy of education which is close to 0.70 (only for Cronbach’s alpha but not for CR). Furthermore, the AVE of each construct exceeded the variance attributable to its measurement error cut-off value of 0.50 (Chin, 1998; Fornell & Larcker, 1981). In addition, heterotrait-monotrait ratio (HTMT) is recommended as a better method to test discriminant validity (Henseler, Dijkstra, Sarstedt, Ringle, Diamantopoulos, Straub, Ketchen, Hair, Hult, & Calantone, 2014). The result shows that there is neither value of the HTMT higher than the threshold of 0.85 nor confidence interval containing the value one, indicating that all the constructs exhibit satisfactory discriminant validity. The hypothesized effects in the theoretical model were tested by structural equation modeling (SEM). The first group of models tested the effect of perceived environmental quality on environmental satisfaction through place attachment i.e. initial model (Model A, Model B, Model C), while the second group of models tested the reverse effect of environmental satisfaction on perceived environmental quality through place attachment (Model D, Model E, Model F). Both the full model and the multi-group model were tested. The value of SRMR of the full model that tests either the effect of perceived environmental quality on environmental satisfaction (SRMR = 0.104, t = 41.826, p < 0.001) or the reversed effect (SRMR = 0.106, t = 37.736, p < 0.001) shows that the models fit the data quite well (Dijkstra & Henseler, 2015b). However, the former is little bit more significant. In this study, PREQI is found different impacts on place attachment and environmental satisfaction. This provides evidence to support a similar mechanism of studying residents’ psychology with SERVEQUAL model. However, the model testing is found significantly different between rural and urban samples, indicating a systematic difference in the psychology of rural and urban populations. Quality ? attachment ? satisfaction causal order is found significant and supported by both samples in this study. However, a reversed causal order model (satisfaction ? attachment ? quality) is also supported by the samples. Although the results may not be able to end the debate on alternative models between PREQ, place attachment, and environmental satisfaction, this paper provides empirical evidence from a specific context (urban and rural China) for further research. Specifically, PREQ has a significant impact on place attachment in both urban and rural areas in China. As for the impact of place attachment on environmental satisfaction as well as the indirect impact of PREQ on environmental satisfaction, the influence is more significant in cities of China compared to rural areas. This suggests in the urban areas in China, affective and emotional responses to their lives play an important role to residents. Local government in cities should balance between improving and maintaining quality of the environment and strengthening local residents’ psychological attachment to the place. Governments in rural areas, on the other hand, should lay great focus on the physical aspects of the environment including nature, health, education, commerce, and venture of the rural areas, to enhance residents’ living experience and satisfaction. Further, there are some limitations. Although this study attempts to clarify the framework of “perception-affection-attitude” in the field of environment management, considering the practical implications, the future study could bring the individuals’ behaviors or intentions into this model such as willingness-to-pay for environment-friendly products. It will also benefit from reviewing more literature on community-based social marketing.

Effective Interaction Techniques in Information-Rich Virtual Environments

Jian Chen 한국정보과학회 2003 한국정보과학회 학술발표논문집 Vol.2003 No.2

Comparison Study of the Band-gap Structure of a 1D-Photonic Crystal by Using TMM and FDTD Analyses

Jian-Bo Chen,Yan Shen,Wei-Xi Zhou,Yu-Xiang Zheng,Hai-Bin Zhao,Liang-Yao Chen 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.58 No.42

A variety of numerical methods has been developed to demonstrate the nature of photons propagating in an artificially-composed periodic structure. Differences will be generated by different kinds of numerical approaches. In this work, we carry out two types of numerical calculations, TMM (transfer matrix method) and FDTD (finite different time domain) calculations. In terms of the 1D-photonic crystal structures with two different structures, we illustrate the energy band spectra, and the results show dispersive characteristics for the optical transmission and reflection of the crystal material. Through a discussion of the mechanism, detailed comparison studies are preformed based on the different physical conditions. The results given in the work will help in better understanding the ways in which photons propagate in an artificially-composed periodic structure.

Effect of Primary Holes Structure on Flow Characteristic and Combustion Performance of High Temperature Rise Combustor Based on RQL

Jian Chen,Jianzhong Li,Qingqing Dong,Jiutian Xue,Ge Hu 한국항공우주학회 2023 International Journal of Aeronautical and Space Sc Vol.24 No.3

To meet the qualification of temperature rise and reduce emissions, a high temperature rise combustor which is based on RQL (rich-burn/quick-quench/lean-burn) under different primary holes structure had been used to investigate the flow characteristic and combustion performance. The flow field was measured by PIV (particle imaging velocimetry) under different primary holes structure at normal temperature and pressure, and the combustion and emissions performances were simulated under the same conditions in this paper. The results show that the flow field, the airflow mixing effectiveness in the quench zone airflow, the distribution of temperature, the emission and the combustion efficiency change obviously with the primary holes structure. The maximum central recirculation zone height with staggered structure (Case-II) is about 23% higher than that with symmetrical structure. The central recirculation zone length is reduced by 36% and the velocity gradient in the rich zone is increased when the primary holes structure is symmetrical with three holes (Case-I). The insufficient penetration of primary jets has a negative impact to the efficient mixing of the quench zone airflow. Therefore, the symmetrical structure of primary holes is used, increasing the number of holes while reducing the area of single-hole will have a negative impact on the efficient mixing of the quench zone airflow. In addition, when the primary holes structure is symmetrical with four holes (Case-III), the combustion efficiency was reduced by 0.07% and 0.03%, and the maximum emission index of NO was increased by 14% and 19%, respectively, compared with the Case-I and Case-II. On the contrary, the maximum emission index of CO and soot were reduced in rich zone.