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MEASUREMENT AND ESTIMATION OF THE SCALE FACTORS AND IMAGE CENTER FOR MACHINE VISION
Lei, Xuan,Yuyan, Wu,Hua, Xu Jian 대한전자공학회 1992 HICEC:Harbin International Conference on Electroni Vol.1 No.1
This paper develops a measuring method for calibrating certain intrinsic camera parameters for machine vision. The parameters to be calibrated are the scale factors (horizontal scale factor and vertical scale factor) and the image center [2]. It is accurate and efficient due to a experimental setup. A least mean square estimation of the scale factors based on stereo vision is also proposed in this paper. It permits the use of only one coplanar set of calibration points without 3-D measurement, and estimates horizontal scale factor and vertical scale factor independently. Experimental results based on TV cameras are demonstrated with high accuracy.
Xuan, Zhu,Zhong, Zhao-Hui,Zhang, Xuan-Zhi,Zhang, Lei,Zhao, Xiao-Kun,Lv, Chen,Xu, Ran,Ren, Wei-Gang,Li, Song-Chao Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.3
To determine the relationship between comorbidity and outcome after radical cystectomy in Chinese patients by using the Adult Comorbidity Evaluation (ACE)-27 index. Two-hundred-and-forty-six patients treated with radical cystectomy at the Second Xiangya Hospital of Central South University, Hunan Province, China between 2000 and 2010 were retrospectively analyzed. Medical records were reviewed for age, gender, delayed time of radical cystectomy, urinary diversion type, pelvic lymphadenectomy status, TNM stage, and pathological grade. Comorbidity information was assessed by the ACE-27 index. The outcome measurement was overall survival. Univariate and multivariate Cox proportional hazards regression analyses were used to determine the association between comorbidity and outcome. The study population consisted of 215 (87.40%) males and 31 (12.60%) females with a mean age of $62{\pm}11$ years. Median duration of follow-up was $47{\pm}31$ months. A total of 151 (61.38%) patents died during follow-up. Of those, 118 (47.97%) had at least one comorbidity. According to the ACE-27 scores, 128 (52.03%) patients had no comorbidity, 79 (32.11%) had mild, 33 (13.41%) had moderate, and 6 (2.45%) had severe comorbidities. Multivariate analysis indicated that moderate (p=0.002) and severe (p<0.001) comorbidity was significantly associated with decreased overall survival. In addition, age ${\geq}70$ years (p=0.002), delayed time of radical cystectomy >12 weeks (p=0.044), pelvic lymphadenectomy status (p=0.014), and TNM stage >T3 (p<0.001) were determined to be independent risk factors of overall survival. Increasing severity of comorbidity statistically correlated with decreased overall survival after radical cystectomy.
Multistability in a driven nanowire system
Xuan Ni,Lei Ying,Ying-Cheng Lai,Younghae Do 한국산업응용수학회 2012 한국산업응용수학회 학술대회 논문집 Vol.7 No.2
Nanoscale systems are the subject of forefront interdisciplinary research. The underlying physics renders dynamics of nanosystems nonlinear. Despite extensive research on chaotic dynamics in low-dimensional dynamical systems, little has been done for nanoscale systems. Due to the potentially widespread use of nanoscale systems in science, engineering, and technological applications, it is imperative to investigate and exploit nonlinear dynamics in such systems. This paper addresses this fundamental topic by investigating a prototypical class of nanoelectromechanical systems (NEMS): electrostatically driven Si-nanowires. We find that multistability and complicated structures of basin of attraction are common, and the latter can be attributed to high-dimensional transient chaos. Implications of these phenomena to device operations are explored.
Lei Li,Li-Jie Zhang,Ning Zhang,Fei Hu,Yin Jiang,Chun-Yi Xuan,Wei-Mei Jiang 한국풍공학회 2010 Wind and Structures, An International Journal (WAS Vol.13 No.6
A meteorological model, RAMS, and a commercial computational fluid dynamics (CFD) model, FLUENT are combined as a one-way off-line nested modeling system, namely, RAMS/FLUENT system. The system is experimentally applied in the wind simulation over a complex terrain, with which numerical simulations of wind field over Foyeding weather station located in the northwest mountainous area of Beijing metropolis are performed. The results show that the method of combining a meteorological model and a CFD model as a modeling system is reasonable. In RAMS/FLUENT system, more realistic boundary conditions are provided for FLUENT rather than idealized vertical wind profiles, and the finite volume method (FVM) of FLUENT ensures the capability of the modeling system on describing complex terrain in the simulation. Thus, RAMS/FLUENT can provide fine-scale realistic wind data over complex terrains.
Lei Zhang,Fengqiong Yu,Qian Hu,Yuxi Qiao,Rongrong Xuan,Gongjun Ji,Chunyan Zhu,Chunlan Cai,Kai Wang 대한신경정신의학회 2020 PSYCHIATRY INVESTIGATION Vol.17 No.9
Objective Attentional biases toward emotional scenes may represent vulnerability and maintenance factors in depression. Antidepressant therapy may improve cognitive function and reduce depression, and is considered as the mechanism of action of antidepressants. Therefore, we conducted an eye-tracking test to examine whether selective serotonin re-uptake inhibitor (SSRI) antidepressants can reduce negative attentional biases and elicit clinical responses in depression. Methods Twenty first-episode depressive patients freely viewed three types of pictures that depicted different emotional scenes (i.e., positive-control, neutral-control, and negative-control) for 4,000 ms while their eye movements were monitored. The attentional bias to different emotional scenes was assessed before and after eight weeks of SSRI treatment using the eye-tracking method. The control group included a group of healthy individuals. Results The results revealed that first-episode depressive patients oriented their gaze more frequently to negative images and less to happy images, compared to controls. Importantly, the attentional bias in depressive patients was regulated after eight weeks of SSRI treatment. Patients showed an increased tendency to fixate on positive images and a decreased tendency to focus on negative images. Conclusion This suggests that SSRI antidepressants decrease vulnerability to negative images, while having an effect on attention in respect to positive images.
Lei Chi,Dai-Di Fan,Xiao-Xuan Ma,Yan-E Luo,Chen-Hui Zhu 한국생물공학회 2011 Biotechnology and Bioprocess Engineering Vol.16 No.3
To increase the biomass and production of recombinant human-like collagen (RHLC), the effect of controlled fermentor pressure during fed-batch cultivation was investigated using recombinant Escherichia coli producing RHLC. This study focused primarily on the effects of the fermentor pressure on the oxygen transfer capacity. A twostep exponential feeding strategy was used to control the specific growth rate at 0.2 and 0.1/h in the fed-batch and induction phase, respectively. A kinetic model of cell growth was developed, and the specific growth rate, specific glucose uptake rate, concentration of extracellular DNA, and percentage of plasmid loss were calculated and detected. The results demonstrated that increasing the fermentor pressure was an effective way of avoiding the oxygen transfer capacity limitation, and an increase in the dissolved CO2 content did not affect the growth of the recombinant E. coli BL21strain. At the end of the fermentation process, the cell density (represented by the dry cell weight, DCW) reached 77.3 g/L, and the RHLC concentration reached 14.1 g/L. In addition,the oxygen transfer capacity (KLaC^*) decreased drastically at approximately 5 h after induction. This is probably because of the increased concentration of extracellular DNA due to cell lysis, indicating that the cells needed to be harvested.
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.
Effect of humidity on mechanical properties of dissolving microneedles for transdermal drug delivery
Qi Lei Wang,Jia Wei Ren,Bo Zhi Chen,Xuan Jin,Can Yang Zhang,Xin Dong Guo 한국공업화학회 2018 Journal of Industrial and Engineering Chemistry Vol.59 No.-
Dissolving microneedles (DMNs) prepared from soluble polymers has been being widely investigated as a safe and effective transdermal delivery system for drug and vaccine. Limited by the materials, the air humidity would probably affect the mechanical property of DMNs, which is essential for the effective needle insertions and drug delivery. In this study, four kinds DMNs prepared by polyvinyl alcohol, sodium hyaluronate (HA), chitosan and gelatin are studied on the mechanical strength and insertion ability under varying humidity conditions. Based on these investigations, we hope to provide the effective time of DMNs to ensure a successful insertion and drug delivery.
Complex dynamics in nanosystems.
Ni, Xuan,Ying, Lei,Lai, Ying-Cheng,Do, Younghae,Grebogi, Celso Published by the American Physical Society through 2013 Physical review. E, Statistical, nonlinear, and so Vol.87 No.5
<P>Complex dynamics associated with multistability have been studied extensively in the past but mostly for low-dimensional nonlinear dynamical systems. A question of fundamental interest is whether multistability can arise in high-dimensional physical systems. Motivated by the ever increasing widespread use of nanoscale systems, we investigate a prototypical class of nanoelectromechanical systems: electrostatically driven Si nanowires, mathematically described by a set of driven, nonlinear partial differential equations. We develop a computationally efficient algorithm to solve the equations. Our finding is that multistability and complicated structures of basins of attraction are common types of dynamics, and the latter can be attributed to extensive transient chaos. Implications of these phenomena to device operations are discussed.</P>