Classroom Negotiation and Learner Participation

Xuehui Liu,Guoxia Zhao 아시아영어교육학회 2004 The Journal of Asia TEFL Vol.1 No.1

Quantifying carotid stiffness in a pre-hypertensive population with ultrafast ultrasound imaging

Xuehui Ma,Zhengqiu Zhu,Yinping Wang,Bixiao Shen,Xuezhong Jiang,Wenjun Liu,Yiyun Wu,Chong Zou,Yun Luan,Hui Gao,Hui Huang 대한초음파의학회 2023 ULTRASONOGRAPHY Vol.42 No.1

Purpose: The aim of this study was to assess carotid stiffening in a pre-hypertensive (PHT) population using ultrafast pulse wave velocity (ufPWV). Methods: This study retrospectively enrolled 626 individuals who underwent clinical interviews, serum tests, and assessments of the systolic blood pressure (SBP), diastolic blood pressure (DBP), carotid intima-media thickness (cIMT), pulse wave velocity-beginning of systole (PWV-BS), and pulse wave velocity-end of systole (PWV-ES) between January 2017 and December 2021. The patients were divided into three groups according to their blood pressure (BP)—normal BP (NBP): SBP <130 mmHg and DBP <80 mmHg (n=215); PHT: 130 mmHg≤SBP<140 mmHg and/or 80 mmHg≤DBP<90 mmHg (n=119); hypertensive (HT): SBP ≥140 mmHg and/or DBP ≥90 mmHg (n=292). Correlation analyses and comparisons were performed among the groups and in the cIMT subgroups (cIMT ≥0.050 cm and <0.050 cm). Results: cIMT and PWV-ES significantly differed among the BP groups (P<0.05). The BP groups had similar PWV-BS when cIMT <0.050 cm or cIMT ≥0.050 cm (all P>0.05). However, the NBP group had a notably lower PWV-ES than the PHT (P<0.001 and P=0.024) and HT (all P<0.001) groups in both cIMT categories, while the PWV-ES in the PHT group were not significantly lower than in the HT group (all P>0.05). Conclusion: Carotid morphological and biomechanical properties in the PHT group differed from those in the NBP group. ufPWV could be used for an early evaluation of carotid stiffening linked to pre-hypertension.

An analysis of physiological index of differences in drought tolerance of tomato rootstock seedlings

Xuehui Yao,Rui Yang,Fukuan Zhao,Shaohui Wang,Changbao Li,Wenchao Zhao 한국식물학회 2016 Journal of Plant Biology Vol.59 No.4

Drought is one of the most limiting factors for plant growth and development. In this study, experiments were carried out on five tomato rootstocks were subjected to water withdrawal and re-watering. Two RKN (root-knot nematodes)-and drought-dual resistant rootstocks were identified according to phenotype, physiological and molecular indexes such as the leaf relative water content (LRWC), electrolyte leakage (EL), water loss of the leaf, proline content, and increased activities of antioxidant enzymes, including peroxidase (POD), ascorbate peroxidase (APX), glutathione reductase (GR), dehydroascorbate reductase (DHAR) and the transcript levels of drought stress marker genes. Further, we preliminarily investigated the mechanism underlying improved drought tolerance arising from grafting. These results will promote the application of these rootstocks in tomato production and provide new information on the mechanism of tomato grafting.

An Estimation Method for the Efficiency of Light-Emitting Diode (LED) Devices

Xuehui Tao,Bin Yang 전력전자학회 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.2

The efficiency of light-emitting diode (LED) devices is a significant factor that reflects the capability of these devices to convert electrical power into optical power. In this study, a method for estimating the efficiency of LED devices is proposed. An efficiency model and a heat power model are established as convenient tools for LED performance evaluation. Such models can aid in the design of LED drivers and in the reliability evaluation of LED devices. The proposed estimation method for the efficiency and heat power of LED devices is verified by experimentally testing two types of commercial LED devices.

Optical Design of a Snapshot Nonmydriatic Fundus-imaging Spectrometer Based on the Eye Model

Xuehui Zhao,Jun Chang,Wenchao Zhang,Dajiang Wang,Weilin Chen,Jiajing Cao 한국광학회 2022 Current Optics and Photonics Vol.6 No.2

Fundus images can reflect ocular diseases and systemic diseases such as glaucoma, diabetes mellitus, and hypertension. Thus, research on fundus-detection equipment is of great importance. The fundus camera has been widely used as a kind of noninvasive detection equipment. Most existing devices can only obtain two-dimensional (2D) retinal-image information, yet the fundus of the human eye also has spectral characteristics. The fundus has many pigments, and their different distributions in the eye lead to dissimilar tissue penetration for light waves, which can reflect the corresponding fundus structure. To obtain more abundant information and improve the detection level of equipment, a snapshot nonmydriatic fundus imaging spectral system, including fundus-imaging spectrometer and illumination system, is studied in this paper. The system uses a microlens array to realize snapshot technology; information can be obtained from only a single exposure. The system does not need to dilate the pupil. Hence, the operation is simple, which reduces its influence on the detected object. The system works in the visible and near-infrared bands (550–800 nm), with a volume less than 400 mm × 120 mm × 75 mm and a spectral resolution better than 6 nm.

Method for estimating workability of self-compacting concrete using mixing process images

Xuehui An,Shuyang Li 사단법인 한국계산역학회 2014 Computers and Concrete, An International Journal Vol.13 No.6

Estimating the workability of self-compacting concrete (SCC) is very important both in laboratories and on construction site. A method using visual information during the mixing process was proposed in this paper to estimate the workability of SCC. First, fourteen specimens of concrete were produced by a single-shaft mixer. A digital camera was used to record all the mixing processes. Second, employing the digital image processing, the visual information from mixing process images was extracted. The concrete pushed by the rotating blades forms two boundaries in the images. The shape of the upper boundary and the vertical distance between the upper and lower boundaries were used as two visual features. Thirdly, slump flow test and V-funnel test were carried out to estimate the workability of each SCC. Finally, the vertical distance between the upper and lower boundaries andthe shape of the upper boundary were used as indicators to estimate the workability of SCC. The vertical distance between the upper and lower boundaries was related to the slump flow, the shape of the upper boundary was related to the V-funnel flow time. Based on these relationships, the workability of SCC could be estimated using the mixing process images. This estimating method was verified by three more experiments. The experimental results indicate that the proposed method could be used to automatically estimate SCC workability.

A Novel Dual-Mode Bandpass Filter Based on a Defected Waveguide Resonator

Xuehui Guan,Wei Fu,Haiwen Liu,안달,임종식 한국전자통신연구원 2011 ETRI Journal Vol.33 No.6

A novel dual-mode bandpass filter (BPF) using a dual spiral-shaped defected ground waveguide (DGW) resonator is proposed in this letter. The dual-mode characteristic of this filter is achieved by loading a defected T-shaped stub at the midline of the spiral-shaped DGW resonator. Also, non-orthogonal input and output feed-lines are adopted in the filter. Based on the compact DGW structure, a dual-mode BPF with central frequency of 1.5 GHz for the global positioning system is designed, fabricated, and measured. Measured results agree well with the predicted response and verify the proposed methodology.

Policy Choices and Resilience to International Monetary Shocks

Xuehui Han,Shang-Jin Wei 연세대학교 동서문제연구원 2014 Global economic review Vol.43 No.4

The well-known trilemma theory states that the nominal exchange rate regime plays a crucial role in a country’s ability to pursue monetary policy that is for its domestic objectives independent from other countries’ influences. In particular, a flexible exchange rate is required for an independent monetary policy. Capital controls may help a country with a fixed exchange rate to gain some policy space but the effect of capital controls is leaky and often short-lived. We revisit these conventional wisdoms and find no strong evidence supporting them in practice. In particular, a flexible exchange rate does not reliably deliver monetary policy independence, but capital controls do. This is consistent with the view that most (developing) countries dislike either depreciation or appreciation of their currencies, and therefore would choose to follow US monetary policy moves even if they are on a flexible exchange rate regime. In other words, to build resilience to international monetary policy shocks, capital controls are a necessarily component.

Computer aided reinforcement design of RC structures

Xuehui An,Koichi Maekawa 한국계산역학회 2004 Computers and Concrete, An International Journal Vol.1 No.1

In this study, a design process for reinforced concrete structures using the nonlinear FEM analysis is developed. Instead of using the nonlinear analysis to evaluate the required performance after design process, the nonlinear analysis is applied before designing the reinforcement arrangement inside the RC structures. An automatic reinforcement generator for computer aided reinforcement agreement is developed for this purpose. Based on a nonlinear FEM program for analyzing the reinforced concrete structure, a smart fictitious material model of steel, is proposed which can self-adjust the reinforcement to the required amount at the cracking location according to the load increment. Using this tool, the reinforcement ratio required at design load level can be decided automatically. In this paper, an example of RC beam with opening is used to verify the proposed process. Finally, a trial design process for a real size underground RC LNG tank is introduced.

BGP Fast Convergence Based on Message Classification

Wu Xuehui 보안공학연구지원센터 2013 International Journal of Future Generation Communi Vol.6 No.6