Chaotic Dynamics of a Three-phase Clock-driven Oscillator with Dual Voltage Controllability

Ji Chao Zhou,송한정 한국물리학회 2012 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.61 No.8

In this work, we study a novel dual voltage controlled chaotic oscillator using a three-phase clock. The chaotic oscillator is based on two nonlinear functions which are needed for chaotic signal generation. The proposed chaotic circuit consists of non-overlapping clock driven three MOS (Metal Oxide Semiconductor) switches for S/H (sample and hold), a level shifter and two nonlinear functions for nonlinearity in the feedback. After optimizing of nonlinear functions for chaotic signal generation, the proposed circuit was simulated with SPICE (Simulation Program with Integrated Circuit Emphasis) program using a 0.6 um CMOS (complementary metal oxide semiconductor) process parameter. For various control voltages, its chaotic dynamics such as time waveform, bifurcation diagram and state transition diagram were analyzed. We confirmed that the circuit can generate discrete chaotic signals in specific control voltages. This circuit expected to be utilized for various chaos applications.

Investigation on aerodynamic instability of high-voltage transmission lines under rain-wind condition

Chao Zhou,Yibing Liu,Zhiyong Ma 대한기계학회 2015 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.29 No.1

Under rain-wind conditions, rain-wind induced aerodynamic instability phenomenon often occurs on high-voltage transmission lines. Like the effects of any other oscillations, this kind of vibration intensifies the fatigue of high-voltage conductors, especially on line supportsor clamps. The presence of raindrops and wind associated with electric field maybe the main cause of this phenomenon. On rainydays, raindrops hit the transmission line and suspends to the high-voltage conductor. The suspended raindrops form upper rivulet andlower rivulet and take an elliptical arch shape along the surface of the high-voltage conductor by action of the wind, if rainfall is sufficient. Moreover, the rivulets are enlarged as a cone shape with the electric field of high-voltage conductor. The upper rivulet’s effect onthe original cross-section formation of the high-voltage conductor and its movement are likely to be the cause of aerodynamic instability. The objective of this paper is to validate a two-dimensional model to investigate the effects of different parameters (electric field strength,wind velocity, frequency and damping ratio of the dynamic system) on aerodynamic stability of the conductor. The Lyapunov stabilitytheory is applied to the model to derive the criterion for the instable angle of the rivulet. Moreover, an experimental conductor modelwith a moveable artificial upper rivulet is set-up and tested in a wind tunnel. The theoretical results are in good agreement with the experimentaldata. The model enable better comprehension of the rain-wind induced aerodynamic instability on the conductor.

Mechanism and characteristic of rain-induced vibration on high-voltage transmission line

Zhou Chao 대한기계학회 2012 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.26 No.8

Under the rainy weather, rain-induced vibration on high-voltage (HV) transmission line often occurs, which intensifies fatigue conductors and tower callapses. Mechanism and control measures of the rain-induced vibration have aroused wide attention in power engineering. The mechanism can be explained that the droplets suspended to the conductors amplify corona discharges with ionic wind, forms non-circular cross-sections, and the rain-induced vibration is due to the coupling action of vortex-induced vibration by ionic wind and galloping vibration by external wind force. Based on the mechanism, a valid model on the rain-induced vibration on high-voltage transmission line is proposed based on the finite element theory and the Newmark algorithm. Taking the conductor LGJ-240 as an instance,we investigate the effects of ionic wind and non-circular cross-sections with different parameters on amplitude of the conductors. The result shows non-circular cross-sections have obviously effects, and the ionic wind have a certain influence and easily to coupling with wind force. Mechanism and conclusions in this paper can be used as references to construct High-voltage transmission lines, upgrade the existing lines and control vibration.

Mechanism and modeling of rain-wind induced in-plane vibration on high-voltage transmission line

Chao Zhou,Yan-ping Liu,Yu-wang Song 대한기계학회 2014 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.28 No.4

In the planning of ultra high-voltage transmission lines that crossover southeast regions of China, one of the key questions is the predictionof vibrations in the conditions of a complex terrain, rainfalls and wind. As the presence of raindrops in the wind filed influencesthe dynamic stability of the transmission line, the objective of this paper is reveal the mechanism of rain-wind induced in-plane vibrationby analyzing the effects of time-varying mass of raindrops and the motion of upper rivulet that is suspended to the high-voltage transmissionline. A rain-wind induced in-plane vibration model with time-varying mass is proposed base on the finite element method and thecentral difference method. Applying our method to the Tuo-chang transmission line, we use the finite element method to develop thenumerical model of the transmission line movement under the action of wind and corona forces, while time discretization is made withthe central difference method. The results show that the time-varying mass of raindrops and moving upper rivulet have obvious effects,and the model enables better comprehension of the rain-wind induced in-plane vibrations of transmission lines.

Bandwidth-Related Optimization in High-Speed Frequency Dividers using SiGe Technology

Chao-Zhou Nan,Xiao-Peng Yu,Wei-Meng Lim,Bo-Yu Hu,Zheng-Hao Lu,Yang Liu,Kiat-Seng Yeo 대한전자공학회 2012 Journal of semiconductor technology and science Vol.12 No.1

In this paper, the trade-off related to bandwidth of high-speed common-mode logic frequency divider is analyzed in detail. A method to optimize the operating frequency, band-width as well as power consumption is proposed. This method is based on bipolar device characteristics, whereby a negative resistance model can be used to estimate the optimal normalized upper frequency and lower frequency of frequency dividers under different conditions, which is conventionally ignored in literatures. This method provides a simple but efficient procedure in designing high performance frequency dividers for different applications. To verify the proposed method, a static divide-by-2 at millimeter wave ranges is implemented in 180 ㎚ SiGe technology. Measurement results of the divider demonstrate significant improvement in the figure of merit as compared with literatures.

Modeling and numerical analysis of corona-induced vibration on High-voltage transmission line with raindrops

Chao Zhou,Yibing Liu,Yan-ping Liu 대한기계학회 2015 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.29 No.11

In rainy days, rainfall hitting high-voltage transmission lines forms raindrops that suspended to lower surface of the conductors. Thesuspended raindrops subjected to electric field take a cone shape, which leads to a drastic increase in local electric field and amplifies thecorona discharge. Electrostatic attractive force between the conductor and the ground is partially shielded by space charge during thecorona discharge. Intermittent shielding and the time lags may be the main causes of this phenomenon namely corona-induced vibration. Like any other mechanical oscillations, this kind of vibration may result in fatigue damages of conductors, failures of insulator stringsand spacers. This paper is to validate a numerical model based on the finite element method and Newmark algorithm to reveal the formationmechanism of the corona-induced vibrations. According to the numerical model, the effect of rain intensity, electric field and appliedvoltage on vibration amplitudes and natural frequency are systematically investigated. The results agree well with experimental dataavailable in the literature. The model and numerical analysis method enable a better comprehension of the formation mechanism of thecorona-induced vibrations.

Construction of a Protein-Protein Interaction Network for Chronic Myelocytic Leukemia and Pathway Prediction of Molecular Complexes

Zhou, Chao,Teng, Wen-Jing,Yang, Jing,Hu, Zhen-Bo,Wang, Cong-Cong,Qin, Bao-Ning,Lv, Qing-Liang,Liu, Ze-Wang,Sun, Chang-Gang Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.13

Background: Chronic myelocytic leukemia is a disease that threatens both adults and children. Great progress has been achieved in treatment but protein-protein interaction networks underlining chronic myelocytic leukemia are less known. Objective: To develop a protein-protein interaction network for chronic myelocytic leukemia based on gene expression and to predict biological pathways underlying molecular complexes in the network. Materials and Methods: Genes involved in chronic myelocytic leukemia were selected from OMIM database. Literature mining was performed by Agilent Literature Search plugin and a protein-protein interaction network of chronic myelocytic leukemia was established by Cytoscape. The molecular complexes in the network were detected by Clusterviz plugin and pathway enrichment of molecular complexes were performed by DAVID online. Results and Discussion: There are seventy-nine chronic myelocytic leukemia genes in the Mendelian Inheritance In Man Database. The protein-protein interaction network of chronic myelocytic leukemia contained 638 nodes, 1830 edges and perhaps 5 molecular complexes. Among them, complex 1 is involved in pathways that are related to cytokine secretion, cytokine-receptor binding, cytokine receptor signaling, while complex 3 is related to biological behavior of tumors which can provide the bioinformatic foundation for further understanding the mechanisms of chronic myelocytic leukemia.

Lamp Creativity Based on Chinese Huizhou Architecture

Zhou Chao(주초) 한국디자인학회 2023 한국디자인학회 국제초대전도록 Vol.2023 No.12

Apoptotic Effects of psiRNA-STAT3 on 4T1 Breast Cancer Cells in Vitro

Zhou, Yue,Tian, Lin,Zhang, Ying-Chao,Guo, Bao-Feng,Zhou, Qing-Wei Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.16

Background: The aim of this study was to investigate the effect of a Lipofectamine2000 (Life2000) Transfection Reagent transfected psiRNA-STAT3 plasmid on 4T1 breast cancer cells. Materials and Methods: MTT was used to detect the cell proliferation of breast cancer 4T1 cells at different periods (0h, 6h, 8h, 10h); the cell cycle was assessed by flow cytometry; variation of apoptosis and mitochondrial membrane potential was observed under a fluorescence microscope; immunohistochemical staining was used to determine the expression of caspase-3 and cyclin-D1 protein. Results: An obvious effect of inhibition to 4T1 cancer cells could be observed at 8h after the psiRNA-STAT3 was transfected. Typical alterations of apoptotic morphological features were visible in the psiRNA-STAT3 treatment group. Mitochondrial membrane potential decreased significantly, the number of cells was increased in G0/G1 phase, and the number of cells was decreased in S phase, and the data were statistically significant (p<0.05), compared with the Scramble and Mock groups. Expression of caspase-3 protein was increased significantly, while that of cyclin D1 was significantly decreased. Conclusions: Life2000 transfected psiRNA-STAT3 plasmid can inhibit 4T1 tumor cell proliferation and promote apoptosis of 4T1 tumor cells, which process depends on the regulation of expression of cyclin D1 and caspase-3 protein.

Systematic Review and Meta-Analysis of Antibiotic-Impregnated Shunt Catheters on Anti-Infective Effect of Hydrocephalus Shunt

Zhou, Wen-xiu,Hou, Wen-bo,Zhou, Chao,Yin, Yu-xia,Lu, Shou-tao,Liu, Guang,Fang, Yi,Li, Jian-wen,Wang, Yan,Liu, Ai-hua,Zhang, Hai-jun The Korean Neurosurgical Society 2021 Journal of Korean neurosurgical society Vol.64 No.2

Objective : Shunt infection is a common complication while treating hydrocephalus. The antibiotic-impregnated shunt catheter (AISC) was designed to reduce shunt infection rate. A meta-analysis was conducted to study the effectiveness of AISCs in reduction of shunt infection in terms of age, follow-up time and high-risk patient population. Methods : This study reviewed literature from three databases including PubMed, EMBASE, and Cochrane Library (from 2000 to March 2019). Clinical studies from controlled trials for shunt operation were included in this analysis. A subgroup analysis was performed based on the patient's age, follow-up time and high-risk population. The fixed effect in RevMan 5.3 software (Cochrane Collaboration) was used for this meta-analysis. Results : This study included 19 controlled clinical trials including 10105 operations. The analysis demonstrated that AISC could reduce the infection rate in shunt surgery compared to standard shunt catheter (non-AISC) from 8.13% to 4.09% (odds ratio [OR], 0.48; 95% confidence interval [CI], 0.40-0.58; p=0.01; I2=46%). Subgroup analysis of different age groups showed that AISC had significant antimicrobial effects in all three groups (adult, infant, and adolescent). Follow-up time analysis showed that AISC was effective in preventing early shunt infections (within 6 months after implant). AISC is more effective in high-risk population (OR, 0.24;95% CI, 0.14-0.40; p=0.60; I2=0%) than in general patient population. Conclusion : The results of meta-analysis indicated that AISC is an effective method for reducing shunt infection. We recommend that AISC should be considered for use in infants and high-risk groups. For adult patients, the choice for AISC could be determined based on the treatment cost.