The static response of functionally graded radially polarized piezoelectric spherical shells as sensors and actuators

Li, Xian-Fang,Peng, Xu-Long,Lee, Kang Yong Institute of Physics Publishing 2010 Smart materials & structures Vol.19 No.3

<P>This paper analyzes the static response of a functionally graded spherical shell made of piezoelectric materials. A hollow piezoelectric sphere is polarized in the radial direction. Spherically symmetric problems of piezoelectric spherical shells as sensors or actuators are considered. For the gradient of power-law behavior, closed-form explicit expressions for the electroelastic field are derived. These solutions can serve as benchmarks for functionally graded piezoelectric hollow spheres. For arbitrarily varying gradient, an analytic approach for reducing the problem to a Fredholm integral equation is suggested to obtain the responses of the electroelastic field. Numerical results for a spherical piezoelectric vessel are obtained for special radial nonhomogeneity, and the distribution of the radial and circumferential stresses as well as the response of the electric potential for sensors and actuators are presented graphically under electrical and mechanical stimuli, respectively. Our results indicate that the gradient index strongly affects the stress distribution and electric response. The obtained results are helpful for optimizing the design of hollow spherical piezoelectric transducers. </P>

Combined Screening of Cervical Cancer, Breast Cancer and Reproductive Tract Infections in Rural China

Li, Zhi-Fang,Wang, Shao-Ming,Shi, Ju-Fang,Zhao, Fang-Hui,Ma, Jun-Fei,Qiao, You-Lin,Feng, Xiang-Xian Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.7

Objectives: To investigate the current prevalence and knowledge of cervical cancer, breast cancer and reproductive tract infections (RTIs) in rural Chinese women, and to explore the acceptance and feasibility of implementing a combined screening program in rural China. Methods: A population-based, cross-sectional study was conducted among women aged 30 to 59 years old in Xiangyuan County, Shanxi Province from 2009 to 2010. Socio-demographic characteristics, knowledge of cervical cancer, breast cancer and RTIs, and the attitude toward single or combined screening were collected by an interview questionnaire. Each participant received a clinical examination of the cervix, breast and reproductive tract. Examinations included visual inspection, mammography, laboratory tests and pathological diagnosis. Results: A total of 1,530 women were enrolled in this study. The prevalence of cervical precancerous lesions, suspicious breast cancer, suspicious benign breast disease and RTIs was 1.4%, 0.2%, 14.0% and 54.3%, respectively. Cervicitis, trichomonas vaginitis, and bacterial vaginitis were the three most common RTIs among our participants. Television, radio broadcast, and public education during screening were the major source of healthcare knowledge in rural China. Moreover 99.7% of women expressed great interest in participating in a combined screening project. The affordable limit for combined screening project was only 50 RMB for more than half of the rural women. Conclusion: A combined screening program would be more effective and popular than single disease screening projects, while appropriate accompanied education and a co-pay model for its successful implementation need to be explored, especially in low-resource settings.

Size effects of the bending stiffness of nanowires

Li, Xian-Fang,Wang, Bao-Lin,Lee, Kang Yong American Institute of Physics 2009 JOURNAL OF APPLIED PHYSICS - Vol.105 No.7

<P>This paper studies the size effect in the transverse deformation of nanowires or nanoropes subjected to flexural bending. Based on the classic strain-gradient theory, a continuum approach is proposed, in which the strain energy was expressed in terms of the linear strains and strain gradients, and two additional phenomenological internal parameters were introduced. The governing equation for the flexural deformation of the nanowires was derived according to the principle of minimum potential energy. In particular, the deformations of the nanowires under two support conditions were determined explicitly, i.e., a cantilever nanowire and a fixed nanowire. Numerical examples were demonstrated to indicate the dependence of the effective modulus and bending stiffness upon the nanowire diameter and aspect ratio. The predictions given by the present model are consistent very well with the experimental measurements reported in the recent literature. The proposed model can be further used to explain the size effect in other properties of nanowires such as dynamics and thermal properties, among others. (C) 2009 American Institute of Physics. [DOI: 10.1063/1.3103322]</P>

Size effect in transverse mechanical behavior of one-dimensional nanostructures

Li, Xian-Fang,Wang, Bao-Lin,Tang, Guo-Jin,Lee, Kang Yong Elsevier 2011 Physica E, Low-dimensional systems & nanostructure Vol.44 No.1

<P><B>Abstract</B></P><P>This paper develops the classical strain gradient elasticity theory to investigate the scale-dependent mechanical behavior of one-dimensional (1D) nanostructures. A governing differential equation with two scale parameters is derived, where the curvature of the deflection and the higher-order bending moment are introduced as a pair of additional geometrical constraint and natural loading. Emphasis is placed on the analysis of bending deformation, free vibration and buckling of cantilever nanowires or free-standing nanocolumns. Obtained results are compared with experimental data of carbon nanotube ropes and nanowires available in the literature and they agree well, showing that transverse mechanical properties of nanowires such as bending stiffness are scale-dependent. The model proposed also indicates that the evaluated natural frequencies and critical buckling strains exhibit noticeable size effects. Bending stiffness, natural frequency and buckling load increase as the nanowire diameter drops down. The influence of rotary inertia of cross-section is also analyzed.</P> <P><B>Highlights</B></P><P>► A governing equation for bending dynamics of nanowires is established. ► Reduced Young's modulus is scale-dependent for the radius of gyration in nano-order. ► The computed natural frequencies become larger than those of their counterparts in large scale. ► Buckling load or critical strain is enhanced for nanowires with small diameter. ► Theoretical predictions are in consistency with experimental findings.</P>

Highly synergic adsorption and photocatalytic degradation of walnut shell biochar/NiCr-layered double hydroxides composite for Methyl orange

Xiao-fang Li,Rui-xian Li,Ke-xin Wang,Xiao-qiang Feng 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.126 No.-

Methyl orange (MO) is a kind of azo dye, and will do great harm to the ecological environment. Alleviating this problem by removing MO is crucial role to prevent harmful damage to the environment. In this paper, NiCr layered double hydroxides (LDH) were prepared through hydrothermal method andthen modified with different mass rations of walnut shell biochar. The structure and properties ofbiochar/NiCr-LDH composites were analyzed by Fourier transform infrared spectroscopy (FT-IR), powderX-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) coupled with energy dispersespectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS). Moreover, the adsorption andphotocatalytic degradation behavior of composites on anionic dye MO were investigated. Characterization results indicated that NiCr-LDH was perfectly synthesized and coated on the biochar. All the biochar/NiCr-LDH composites show enhanced adsorption and photodegradation performancefor MO dye compared with pure NiCr-LDH and biochar. When the biochar content was 22.3 wt.% andthe biochar/NiCr-LDH (S2) dosage was 1.0 mg/mL, the maximum removal amount of MO could reach100 % within 60 min at the natural pH, experimental data fitted well with the pseudo-second-orderkinetic and Freundlich isotherm model, and the maximum adsorption capacity of S2 was 108.2 mg/g. Besides, compared with NiCr-LDH, S2 also demonstrated wonderful photodegradation activity for MOunder visible-light irradiation, the rate constant of S2 (0.0173 min1) is about 1.5 times that of NiCr-LDH (0.0118 min1), and the enhanced performance can be due to the faster separation of electronholepairs, in which biochar acted as charge separation carriers. Meanwhile, the hydroxyl radical andsuperoxide radical played crucial roles in the dye photocatalytic degradation, and a possible photocatalyticdegradation mechanism was proposed. The excellent photocatalytic activity and stability makebiochar/NiCr-LDH an ideal photocatalyst to solve environmental crisis.

Sequence Analysis of Mitochondrial Genome of Toxascaris leonina from a South China Tiger

Kangxin Li,Fang Yang,A. Y. Abdullahi,Meiran Song,Xianli Shi,Minwei Wang,Yeqi Fu,Weida Pan,Fang Shan,Wu Chen,Guoqing Li 대한기생충학열대의학회 2016 The Korean Journal of Parasitology Vol.54 No.6

Toxascaris leonina is a common parasitic nematode of wild mammals and has significant impacts on the protection of rare wild animals. To analyze population genetic characteristics of T. leonina from South China tiger, its mitochondrial (mt) genome was sequenced. Its complete circular mt genome was 14,277 bp in length, including 12 protein-coding genes, 22 tRNA genes, 2 rRNA genes, and 2 non-coding regions. The nucleotide composition was biased toward A and T. The most common start codon and stop codon were TTG and TAG, and 4 genes ended with an incomplete stop codon. There were 13 intergenic regions ranging 1 to 10 bp in size. Phylogenetically, T. leonina from a South China tiger was close to canine T. leonina. This study reports for the first time a complete mt genome sequence of T. leonina from the South China tiger, and provides a scientific basis for studying the genetic diversity of nematodes between different hosts.

A Multi-center Survey of HPV Knowledge and Attitudes Toward HPV Vaccination among Women, Government Officials, and Medical Personnel in China

Zhao, Fang-Hui,Tiggelaar, Sarah M.,Hu, Shang-Ying,Zhao, Na,Hong, Ying,Niyazi, Mayinuer,Gao, Xiao-Hong,Ju, Li-Rong,Zhang, Li-Qin,Feng, Xiang-Xian,Duan, Xian-Zhi,Song, Xiu-Ling,Wang, Jing,Yang, Yun,Li, Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.5

Objectives: To assess knowledge of HPV and attitudes towards HPV vaccination among the general female population, government officials, and healthcare providers in China to assist the development of an effective national HPV vaccination program. Methods: A cross-sectional epidemiologic survey was conducted across 21 urban and rural sites in China using a short questionnaire. 763 government officials, 760 healthcare providers, and 11,681 women aged 15-59 years were included in the final analysis. Data were analyzed using standard descriptive statistics and logistic regression. Results: Knowledge of HPV among the general female population was low; only 24% had heard of HPV. Less than 20% of healthcare providers recognized sexually na$\ddot{i}$ve women as the most appropriate population for HPV vaccination. There was high acceptance of the HPV vaccine for all categories of respondents. Only 6% of women were willing to pay more than US $300 for the vaccine. Conclusions: Aggressive education is necessary to increase knowledge of HPV and its vaccine. Further proof of vaccine safety and efficacy and government subsidies combined with increased awareness could facilitate development and implementation of HPV vaccination in China.

Determination of Protein, Fat, Starch, and Amino Acids in Foxtail Millet [Setaria italica (L.) Beauv.] by Fourier Transform Near-Infrared Reflectance Spectroscopy

Xiu-Shi Yang,Li-Li Wang,Xian-Rong Zhou,Shaomin Shuang,Zhi-Hua Zhu,Nan Li,Yan Li,Fang Liu,San-Cai Liu,Ping Lu,Guixing Ren,Chuan Dong 한국식품과학회 2013 Food Science and Biotechnology Vol.22 No.6

Quantitative detection of protein, fat, starch,and amino acids in foxtail millet using Fourier transformnear-infrared spectroscopy (NIRS) was investigated. Foxtail millet samples (n=259) were analyzed using NIRS. Spectral data were linearized with data from chemicalanalyses. Calibration models were established using apartial least-squares (PLS) algorithm with cross-validation. Optimized models were tested using external validation setsamples with coefficients of determination in the externalvalidation (R2val) of >0.90. Residual predictive deviation(RPD) values were nearly equal to or >2.5 for crudeprotein, alanine, aspartic acid, glutamic acid, isoleucine,leucine, and serine. However, for glycine, histidine,phenylalanine, proline, threonine, tyrosine, and valine, theR2val values were >0.83 and RPD values were nearly equalto or >2.0. For crude fat, total starch, arginine, and lysine,the R2val values were >0.70 and RPD values were >1.5. NIRS is a rapid determination tool for foxtail milletbreeding, and for quality control.

Physiological character and molecular mapping of leaf-color mutant wyv1 in rice (Oryza sativa L.)

Xian-chun Sang,Li-kui Fang,Yuenyong Vanichpakorn,Ying-hua Ling,Peng Du,Fang-ming Zhao,Zheng-lin Yang,Guang-hua He 한국유전학회 2010 Genes & Genomics Vol.32 No.2

The seed of an excellent indica restorer line Jinhui10 (Oryza sativa L. ssp. indica) was treated by ethyl methanesulfonate (EMS); a leaf-color mutant displaying distinct phenotype throughout development grown in paddy field was identified from the progeny. The mutant leaf showed white-yellow at seedling stage and then turned to yellow-green at tillering stage, after that, virescent color appeared until to maturity. The mutant was thus temporarily designed as wyv1. The chlorophyll contents decreased significantly and the changing was consistent with the chlorotic level of wyv1 leaves. Chlorophyll fluorescence kinetic parameters measured at the seedling stage showed that co-efficiency of photochemical quenching (qP),actual photosystem II efficiency (ΦPS II), electron transport rate (ETR) and initial chlorophyll fluorescence level (Fo), net photosynthetic rate (Pn) and maximum photochemical efficiency (Fv / Fm) significantly decreased in severe chlorotic leaf of the mutant compared with that of wild type. However,no significant differences were observed for Pn and Fv/Fm between virescent leaf and normal green leaf. Genetic analysis suggested that the mutant phenotype was controlled by a single recessive nuclear gene which was finally mapped between SSR marker Y7 and Y6 on rice chromosome 3 based on F2 population of Xinong1A / wyv1. Genetic distances were 0.06 cM and 0.03 cM respectively, and the physical distance was 84kb according to the sequence of indica rice 9311. The results must facilitate map-based cloning and functional analysis of WYV1 gene.

Control Strategy and Characteristic Analysis of Hybrid Active Power Filters with the Resonant Impedance Principle

Fang, Lu,Xu, Xian-Yong,Luo, An,Li, Yan,Tu, Chun-Ming,Fang, Hou-Hui The Korean Institute of Power Electronics 2012 JOURNAL OF POWER ELECTRONICS Vol.12 No.6

A new kind of resonant impedance type hybrid active filter (RITHAF) is proposed for dynamic harmonic current suppression and high capacity reactive compensation in medium and high voltage systems. This paper analyzed the different performance of the RITHAF when the active part of the RITHAF is controlled as a current source and as a voltage source, respectively. The harmonic suppression function is defined in this paper. The influences of the changes caused by the grid impedance and the detuning of the passive power filter on the compensating characteristics of the RITHAF are studied by analyzing the suppression function. Simulation and industrial application results show that the RITHAF has excellent performances in harmonic suppression and reactive compensation, which is suitable for medium and high voltage systems.