Mathematical and computer simulation for Electro-Magneto- Thermo-Elastic Buckling of the Porous Nano system

Xiaohua Wang,Pinyi Wang,Wei Jiang,Fengqin Wu,Masoud Kiani,Mohammad Arefi 국제구조공학회 2021 Structural Engineering and Mechanics, An Int'l Jou Vol.80 No.2

Buckling analysis of porous sandwich nanoplate integrated with two piezoelectric face-sheets is presented based on shear and normal deformation theory (SNTD). Effect of small scales of the porous core and actuated face-sheets is accounted based on the nonlocal strain gradient theory (NSGT). Large parametric results are presented to investigate variation of various critical loads in terms of significant parameters such as porosity volume fraction, strain gradient and nonlocal parameter, and dimensionless geometric parameters. It is concluded that increase of porosity volume fraction leads to decrease of critical electric and magnetic potentials and increase of critical temperatures.

Parameter Optimal Choice of Claw Pole Alternator based on Iron Loss Model

Bao, Xiaohua,Wei, Qiong,Wu, Feng,Li, Jiaqing Journal of International Conference on Electrical 2013 Journal of international Conference on Electrical Vol.2 No.3

Based on classical Berotti discrete iron loss calculation model, the iron loss analysis mathematical model of alternator was proposed in this paper. Considering characteristics of high speed and changing frequency of the alternator, Maxwell 3-D model was built to analyze iron loss corresponding to each running speed in alternator. Based on iron loss model of alternator at rated speed, the rotor claw pole size was made an optimization design. The optimization results showed that alternator's output performance had been improved. A new idea was explored in size optimization design of claw pole alternator.

Identification of drought response genes in Zygophyllum xanthoxylum by suppression subtractive hybridization

Bin Wu,Xiaohua Su 한국식물학회 2016 Journal of Plant Biology Vol.59 No.4

Drought is an important abiotic stress that seriously limits plant growth and crop productivity in some regions of the world. Zygophyllum xanthoxylum, a succulent xerophyte species with excellent adaptability to adverse arid environments, is an excellent model system for the study of the molecular mechanisms behind drought tolerance in xerophytic species. To better understand the molecular basis of Z. xanthoxylum responses to drought stress and to isolate drought tolerance-related genes from Z. xanthoxylum, we constructed a cDNA library from Z. xanthoxylum and screened the library for stress-related genes by PCR-based suppression subtractive hybridization (SSH). A total of 637 expressed sequence tags were generated by sequencing 672 randomly selected clones, resulting in the identification of 338 unigenes comprising 77 contigs and 261 singlets. The unigenes were assigned to 13 functional categories, such as metabolism, disease- or defense-related genes and energyrelated gene. In addition, we analyzed the expression patterns of 24 genes associated with drought stress-responsive pathways by real-time RT-PCR. The results indicated that osmolyte biosynthesis genes, reactive oxygen scavengers, transporters, signaling components and transcription factors play important roles in drought stress responses. This study provides a valuable resource for studying the drought tolerance mechanism of this xerophytic plant species.

Simultaneous Electrochemical Determination of Hydroquinone, Catechol and Resorcinol at Nitrogen Doped Porous Carbon Nanopolyhedrons-multiwall Carbon Nanotubes Hybrid Materials Modified Glassy Carbon Electrode

Liu, Wei,Wu, Liang,Zhang, Xiaohua,Chen, Jinhua Korean Chemical Society 2014 Bulletin of the Korean Chemical Society Vol.35 No.1

The nitrogen doped porous carbon nanopolyhedrons (N-PCNPs)-multi-walled carbon nanotubes (MWCNTs) hybrid materials were prepared for the first time. Combining the excellent catalytic activities, good electrical conductivities and high surface areas of N-PCNPs and MWCNTs, the simultaneous determination of hydroquinone (HQ), catechol (CC) and resorcinol (RE) with good analytical performance was achieved at the N-PCNPs-MWCNTs modified electrode. The linear response ranges for HQ, CC and RE are 0.2-455 ${\mu}M$, 0.7-440 ${\mu}M$ and 3.0-365 ${\mu}M$, respectively, and the detection limits (S/N = 3) are $0.03{\mu}M$, $0.11{\mu}M$ and $0.38{\mu}M$, respectively. These results are much better than that obtained on some graphene or CNTs-based materials modified electrodes. Furthermore, the developed sensor was successfully applied to simultaneously detect HQ, CC and RE in the local river water samples.

Risk of Dementia in Long-Term Benzodiazepine Users: Evidence from a Meta-Analysis of Observational Studies

Qian He,Xiaohua Chen,Tang Wu,Liyuan Li,Xiaofan Fei 대한신경과학회 2019 Journal of Clinical Neurology Vol.15 No.1

Background and Purpose There is conflicting evidence in the literature on the association between benzodiazepines (BDZs) and the risk of dementia. This meta-analysis aimed to determine the relationship between the long-term usage of BDZs and the risk of dementia. Methods The PubMed and Embase databases were systematically searched for relevant publications up to September 2017. The literature search focused on observational studies that analyzed the relationship between the long-term use of BDZs and the risk of dementia. Pooled rate ratios (RRs) with 95% confidence interval (CI) were assessed using a random-effects model. The robustness of the results was checked by performing subgroup and sensitivity analyses. Results Ten studies were included: six case–control and four cohort studies. The pooled RR for developing dementia was 1.51 (95% CI=1.17–1.95, p=0.002) in patients taking BDZ. The risk of dementia was higher in patients taking BDZs with a longer half-life (RR=1.16, 95% CI= 0.95–1.41, p=0.150) and for a longer time (RR=1.21, 95% CI=1.04–1.40, p=0.016). Conclusions This meta-analysis that pooled ten studies has shown that BDZ significantly increases the risk of dementia in the elderly population. The risk is higher in patients taking BDZ with a longer half-life (>20 hours) and for a longer duration (>3 years).

Advances in diagnosis and treatment of metastatic cervical cancer

Haoran Li,Xiaohua Wu,Xi Cheng 대한부인종양학회 2016 Journal of Gynecologic Oncology Vol.27 No.4

Cervical cancer is one of the most common cancers in women worldwide. The outcome of patients with metastatic cervical cancer is poor. We reviewed the relevant literature concerning the treatment and diagnosis of metastatic cervical cancer. There are two types of metastasis related to different treatments and survival rates: hematogenous metastasis and lymphatic metastasis. Patients with hematogenous metastasis have a higher risk of death than those with lymphatic metastasis. In terms of diagnosis, fluoro-2-deoxy-Dglucose positron emission tomography (FDG-PET) and PET-computed tomography are effective tools for the evaluation of distant metastasis. Concurrent chemoradiotherapy and subsequent chemotherapy are well-tolerated and efficient for lymphatic metastasis. As for lung metastasis, chemotherapy and/or surgery are valuable treatments for resistant, recurrent metastatic cervical cancer and chemoradiotherapy may be the optimal choice for stage IVB cervical cancer. Chemotherapy and bone irradiation are promising for bone metastasis. A better survival is achieved with multimodal therapy. Craniotomy or stereotactic radiosurgery is an optimal choice combined with radiotherapy for solitary brain metastases. Chemotherapy and palliative brain radiation may be considered for multiple brain metastases and other organ metastases.

Soft-switching buck inverter

Xu, Wei,Wu, Xiaohua,Hong, Feng The Korean Institute of Power Electronics 2021 JOURNAL OF POWER ELECTRONICS Vol.21 No.1

The soft-switching buck inverter, which is mainly applied to solve the contradictions between the switching frequency and the shoot-through problem along with the dead-time effect, is proposed in this paper. A detailed analysis of the relationship between the range of the duty ratio to realize soft-switching as well as the additional voltage stress and the current stress is conducted. In addition, a 1 kW prototype is designed and established. Results of simulations and experiments verify the validity of the theoretical analysis. Furthermore, the proposed soft-switching buck inverter has a strong practical significance in situations where medium and high power outputs are required.

Reduced Order Identification and Stability Analysis of DC-DC Converters

Husan Ali,Xiancheng Zheng,Xiaohua Wu,Haider Zaman,Shahbaz Khan 전력전자학회 2017 JOURNAL OF POWER ELECTRONICS Vol.17 No.2

This paper discusses the measurement of frequency response functions for various dc-dc converters. The frequency domain identification procedure is applied to the measured frequency responses. The identified transfer functions are primarily used in developing behavioral models for dc-dc converters. Distributed power systems are based upon such converters in cascade, parallel and several other configurations. The system level analysis of a complete system becomes complex when the identified transfer functions are of high order. Therefore, a certain technique needs to be applied for order reduction of the identified transfer functions. During the process of order reduction, it has to be ensured that the system retains the dynamics of the full order system. The technique used here is based on the Hankel singular values of a system. A systematic procedure is given to retain the maximum energy states for the reduced order model. A dynamic analysis is performed for behavioral models based on full and reduced order frequency responses. The close agreement of results validates the effectiveness of the model order reduction. Stability is the key design objective for any system designer. Therefore, the measured frequency responses at the interface of the source and load are also used to predict stability of the system.

Research on dynamic decoupling control of air supplying loop in fuel cell system based on pressure compensation

Dafeng Song,Fanyong Zeng,Xiaohua Zeng,Qingtao Wu 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.6

This study establishes a simulation model of the voltage output of a fuel cell stack based on its basic design parameters. Under the condition that the number of cells in the stack remains unchanged, the output capacity of the stack from the control level is explored to increase the power level. This study optimizes the system, analyzes the game process between the parasitic power supply system and the output power of the fuel cell stack, and optimizes the output capacity of the fuel cell stack by compensating the backpressure. To strengthen the flow-pressure coupling during pressure compensation, the principle of autodisturbance decoupling control is applied to the strong coupling system to design a flowpressure dynamic decoupling controller that can weaken the flow-pressure coupling effect.

High densification and anti-corrosion of graphene-coated aluminum coating deposited on AZ31B magnesium by low-pressure cold spray

Zhang Liuyan,Wang Xiujin,Wu Huishu,Mai Yongjin,Liu Cansen,Jie Xiaohua 한국탄소학회 2020 Carbon Letters Vol.30 No.5

In this paper, graphene-coated Al powders prepared by in situ reduction method were directly used for cold spraying, obtain�ing a graphene-reinforced Al matrix composite coating with more compact structure and better performance. Cross-sectional analysis revealed that compared with the pure Al powders, the graphene-coated Al powders were more severely deformed, and the resulting coating was denser and its porosity was reduced by over 80%. The hardness of the graphene-coated Al coating was increased by 40%, and its brine immersion time was prolonged by nearly three times. However, the graphene increases the pitting sensitivity of the Al coating; so, the enhanced corrosion resistance of the graphene-coated Al coating is mainly attributed to the improvement of its structure densifcation.