METHOD OF HMI OPTIMIZATION DESIGN BASED ON FIXATION TRANSITION CHARACTERISTICS AND VISUAL ATTENTION TRAJECTORY: A DRIVER SIMULATOR STUDY

Xiaohua Zhao,Dunli Hu,Xinyu Yang,Xuewei Li,Xiaofan Feng,Jiaxia Yang 한국자동차공학회 2022 International journal of automotive technology Vol.23 No.4

To further enhance the role of connected vehicles with the Human-Machine Interface (HMI) in helping drivers in foggy weather, it is meaningful to optimize the HMI based on the driver’s needs. In order to explore the method of HMI optimization, this paper builds a driving simulation experimental test platform of freeway connected vehicle system, designing two experimental scenarios according to the technical conditions (without HMI or with HMI). After that, the paper uses Markov chain to explore the drivers’ fixation transition to identify the driver’s needs in different sections at different conditions. Besides, combined with the visual trajectory results, the paper provides suggestions for optimizing HMI. The results show the review rate of drivers in each section for the straight upper front area is very high. The highest value occurs in the heavy fog zone, suggesting that HMI can provide more road information. HMI should offer a prompt to the driver before entering the warning zone, and remind the driver of changes in the speed limit before entering the fog area. The prompt module of HMI should shorten the horizontal length. In conclusion, this paper aims to propose a general diagnosis method by diagnosing the self-designed HMI.

Novel Rotor Winding Investigation for Reduction of Torque Pulsation and Electromagnetic Noise in Squirrel Cage Induction Motor

Yang Zhou,Xiaohua Bao,Wuhua Jiang,Jiwei Liu,Wei Xu 한국자기학회 2019 Journal of Magnetics Vol.24 No.1

In the design of squirrel-cage induction machines, torque pulsation and electromagnetic noise always exist. However, they cannot be minimized simultaneously with no matter which slot combination. Electromagnetic noise is aroused by the spatial harmonics in the air gap which are generated by stator magneto-motive force and rotor magneto-motive force. Generally, stator slot number cannot be changed while rotor slot number and slot size could be modified optionally. One set of uniform-bar rotor winding cannot solve this problem. To investigate this issue, this paper proposes a novel rotor winding connection topology for the simultaneous reduction of torque pulsation and electromagnetic noise. 2D finite element models with conventional rotor winding and novel rotor winding are simulated and compared.

Battery-free slotted patch antenna sensor for wireless strain and crack monitoring

Xiaohua Yi,Chunhee Cho,Yang Wang,Manos M. Tentzeris 국제구조공학회 2016 Smart Structures and Systems, An International Jou Vol.18 No.6

In this research, a slotted patch antenna sensor is designed for wireless strain and crack sensing. An off-the-shelf RFID (radiofrequency identification) chip is adopted in the antenna sensor design for signal modulation. The operation power of the RFID chip is captured from wireless reader interrogation signal, so the sensor operation is completely battery-free (passive) and wireless. For strain and crack sensing of a structure, the antenna sensor is bonded on the structure surface like a regular strain gage. Since the antenna resonance frequency is directly related with antenna dimension, which deforms when strain occurs on the structural surface, the deformation/strain can be correlated with antenna resonance frequency shift measured by an RFID reader. The slotted patch antenna sensor performance is first evaluated through mechanics-electromagnetics coupled simulation. Extensive experiments are then conducted to validate the antenna sensor performance, including tensile and compressive strain sensing, wireless interrogation range, and fatigue crack sensing.

Calculation of Electromagnetic Excitation Forces in Double Skewed Motors

Xiaohua Bao,Chong Di,Yang Zhou 대한전기학회 2018 Journal of Electrical Engineering & Technology Vol.13 No.2

An electromagnetic excitation force is caused by the air-gap flux density, which greatly influences the noise and vibration of the motor. In many real projects, skewed slot technology is widely used to reduce the harmonic components of the air-gap flux density to reduce the noise and vibration of the motor. However, a skewed slot has several side effects such as a transverse current and axial drifting. Thus, a double skewed slot rotor is selected with the aim of eliminating these side effects. This paper presents the exact structure of the double skewed slot rotor and the mechanism whereby the electromagnetic excitation force can be reduced. A multi-slice method is adopted to model the special structure. Finite element simulation is used to verify the theory.

Direct Determination of Interchain Transfer Constants for Radical Polymerization of Benzyl Acrylate by RAFT Polymerization and Polymer Chromatography

Yang Xue,Xiaohua Li,Shixian Zhang,Ruiwei Guo 한국고분자학회 2021 Macromolecular Research Vol.29 No.7

Chain transfer reactions are important side reactions in the radical polymerization of acrylates. Discrimination between interchain and intrachain transfer is still a challenge for the study of interchain transfer. A prepolymer, poly(benzyl acrylate) with hydroxy terminals (HO-PBzA), was designed and used in the reversible addition-fragmentation chain transfer (RAFT) polymerization of BzA to measure the interchain transfer degree, with benzyl N-carbazole dithiocarbamate (BCBD) as the RAFT agent. Liquid chromatography at critical conditions was used to separate and measure interchain transfer products and then BzA interchain transfer constants (Ctr) at different temperatures determined without other kinetic parameters. Experimental results showed that experimental parameters in RAFT polymerization, except the high dosage of BCBD, had no significant effects on the measured Ctr, which showed good repeatability. The Ctr of benzyl acrylate at 100-120 °C was in the order of 1-2×10-4 and the activation energy of Ctr was at 31.1 kJ∙mol-1.

Calculation of Electromagnetic Excitation Forces in Double Skewed Motors

Bao, Xiaohua,Di, Chong,Zhou, Yang The Korean Institute of Electrical Engineers 2018 Journal of Electrical Engineering & Technology Vol.13 No.2

An electromagnetic excitation force is caused by the air-gap flux density, which greatly influences the noise and vibration of the motor. In many real projects, skewed slot technology is widely used to reduce the harmonic components of the air-gap flux density to reduce the noise and vibration of the motor. However, a skewed slot has several side effects such as a transverse current and axial drifting. Thus, a double skewed slot rotor is selected with the aim of eliminating these side effects. This paper presents the exact structure of the double skewed slot rotor and the mechanism whereby the electromagnetic excitation force can be reduced. A multi-slice method is adopted to model the special structure. Finite element simulation is used to verify the theory.

Numerical Study on Rotating Characteristics of Unsteady Flow Inner Pump-turbine in Pump Mode

Jun Yang,Tian Xie,Pavesi Giorgio,Xiaohua Liu,Jun Liu 한국유체기계학회 2018 International journal of fluid machinery and syste Vol.11 No.3

In order to investigate the formation of the rotating stall in diffuser of pump-turbine in pump mode, the unsteady flow with radial rotating characteristics before the occurrence of rotating stall are investigated by detached eddy simulation. The results indicate that the unsteady flow patterns which occur in the return channel both at full and part load conditions contain two periodical disturbances with frequencies St≈0.042 and St≈0.085, and the Strouhal number St is frequency normalized by blade passing frequency of impeller. These periodical disturbances not only influence the pressure field but also cause rotating characteristics in diffuser channels. One is composed of 4 cells propagating at 0.073 times of impeller rotating speed. The other one is made up of 3 rotating cells with 0.2 times of backward impeller rotating speed. Meanwhile, there are two radial rotating characteristics which contribute the spectra peak at blade pass frequency in diffuser. One is at the inlet of diffuser propagating at impeller rotating speed with 7 cells, and the other one contains 4 cells with about 1.75 backward impeller rotating speed.

INVESTIGATION OF HOMOLOGOUS SERIES AS PRECURSORY HYDROCARBONS FOR ALIGNED CARBON NANOTUBE FORMATION BY THE SPRAY PYROLYSIS METHOD

ZHI YANG,HUAGUI NIE,XUEMEI ZHOU,ZHEN YAO,SHAOMING HUANG,XIAOHUA CHEN 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2011 NANO Vol.6 No.3

The precursory carbon source is one of the key parameters which govern the formation of carbon nanotubes (CNTs). In this work, by selecting four homologous series, namely n-pentane, n-hexane, n-heptane and n-octane, as investigated targets, we comparatively study the relationship between thermodynamic properties of the precursory carbon source and formation of aligned CNTs. We find that all of these alkanes are favored for the growth of aligned CNTs in a suitable growth environment. But only n-heptane can yield the aligned CNTs with relatively high quality, high yield and narrow diameter distribution. Furthermore, after considering the link between thermodynamic properties of the precursory carbon source and the morphology characteristic of the nanotube samples, we find that the Gibbs free energy and formation enthalpy of precursory carbon sources play critical roles in the nanotube formation. In additions some possible explanations are proposed to better understand these phenomena. These rules will be very helpful in making clearer the formation mechanism from the precursory carbon sources to the CNTs, and preparing large-scale aligned CNTs with diameter control at low cost.

SYNTHESIZING A WELL-ALIGNED CARBON NANOTUBE FOREST WITH HIGH QUALITY VIA THE NEBULIZED SPRAY PYROLYSIS METHOD BY OPTIMIZING ULTRASONIC FREQUENCY

ZHI YANG,HUAGUI NIE,XUEMEI ZHOU,ZHEN YAO,SHAOMING HUANG,XIAOHUA CHEN 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2011 NANO Vol.6 No.4

Nebulized spray pyrolysis (NSP) offers ease of scaling into an industrial scale process method for large-scale CNT synthesis. In the method, ultrasonic frequency plays an important role in the formation of well-aligned carbon nanotubes (CNTs). In this work, we obtain well-aligned CNTs with high quality by optimizing ultrasonic frequency via the NSP method. SEM, TEM and HRTEM results show that the aligned CNTs obtained under an ultrasonic frequency of 1.8 MHz have good alignment, uniform nanotube length (~200 μm), high density and no trace of other carbon nanoparticles. The Raman spectra result further confirms that the aligned CNTs have a high graphitization degree. Furthermore, we find that ultrasonic frequency is an important factor in determining the nanotube diameter. The higher the ultrasonic frequency, the smaller the nanotube diameter. This rule may be very helpful in the preparation of large-scale well-aligned CNTs with high quality and diameter-controlled at low cost.

Molecular mechanism of poisoning to honeybees (Apis mellifera L.) after ingestion of Camellia oleifera nectar

Wang Yang,Liu Xiaohua,Wang Yiming,Jin Mingxia,Xie Guai,Zhong Qiuping,Yu Ailin 한국응용곤충학회 2024 Journal of Asia-Pacific Entomology Vol.27 No.1

To explore the molecular mechanism of honeybees (Apis mellifera L.) poisoning death by ingestion of Camellia oleifera nectar, feeding experiments were designed to investigate the poisoning effects. Observed the develop ment process of poisoning symptoms, and collected bees at key experimental nodes for transcriptome sequencing analysis. The results showed that the first poisoning symptom was observed within 0.5 h after ingestion of Camellia oleifera nectar, with death occurring as early as 2 h post-ingestion and all honey bees dying within 4 h. There were four stages in the development of poisoning symptoms: normal flying, crawling (abdominal swelling, inability to fly normally), fluttering (inability to crawl normally), and death. Transcriptome sequencing analyzed the causes of poisoning death indicated that honey bee poisoning occurred with the transduction of dietary restriction signals into cells, resulting in the down-regulated expression gene elements that ensure cell health and inhibit apoptosis, including intracellular NAD+-dependent protein deacetylase sirtuin 1, insulin-like growth factor 1, and heat shock proteins. At the same time, the expression of cysteinyl aspartate specific proteinase 7, which protects programmed cell apoptosis, was also downregulated, resulting in the rapid and disorderly deaths of a large number of cells in individuals in a short period of time, and eventually leading to bees fatality.