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- 저자 : Wang Yanyan (검색결과 62 건)
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Yanyan Nie,Fangyi Li,Liming Wang,Jianfeng Li,Yanle Li,Mingshuai Sun,Mengyao Wang,Guoyan Li 한국정밀공학회 2023 International Journal of Precision Engineering and Vol.10 No.1
As a kind of green energy, wind energy has become cost-competitive mainstream energy in the world. The gearbox is one of the most important and vulnerable components in the wind turbine (WT), which suffers a high failure rate and downtime. It is of great significance to the condition monitoring and fault diagnosis of the WT gearbox. However, in the multistage WT gearbox, the vibrations generated from different stages are coupled, which leads to a complex vibration spectral structure and brings difficulties in condition monitoring and fault diagnosis. Aiming to understand the vibration frequency features of multistage WT gearboxes, a novel phenomenological vibration model is established and the spectral structure is deduced by using the Fourier series analysis. In the vibration model, the phenomenon of inter-stage meshing frequency modulation (ISMFM) is considered, which is clearly proposed for the first time. The theoretical derivations are validated by both simulation and engineering tests using a 2.0 MW industrial WT gearbox. The results show that under healthy conditions, in addition to the meshing frequencies and their harmonics of each stage, there are also ISMFM sidebands in the vibration spectrum of the multistage WT gearbox, and the amplitude of the sidebands will change with the health status of the gearbox. The findings are not only applicable to the WT gearbox studied in this paper, but also to other similar multistage gearbox systems, which can provide a priori spectral structure for a multistage gear transmission system to assist its condition monitoring and fault diagnosis.
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Wang, Jing,Bu, Yanyan,Wang, Xiangfu,Seo, Hyo Jin Elsevier 2018 Optical materials Vol.84 No.-
<P><B>Abstract</B></P> <P>Optical thermometry based on the adjacent thermally coupled levels of rare earth ions has been widely studied in the high temperature range, and shows unobvious effect at low temperature range. In this work, we propose a new method to achieve optical thermometry in 10˜300 K range through manipulating the energy transfer from WO<SUB>6</SUB> <SUP>6−</SUP> to Ho<SUP>3+</SUP>. A comprehensive five-level rate-equation model is developed to establish the relation between lifetime ratios and temperature. It is found that the lifetime ratios of 540 nm (Ho<SUP>3+</SUP>) and 471 nm (WO<SUB>6</SUB> <SUP>6−</SUP>) emissions are dependent on the phonon energy of Y<SUB>2</SUB>WO<SUB>6</SUB> host and temperature. The values of sensor sensitivity reach the maximum 2.1% K<SUP>−1</SUP> at 211 K in 30%Ho<SUP>3+</SUP> doped Y<SUB>2</SUB>WO<SUB>6</SUB>, which is higher than the maximum of the reported phosphors at low temperature. It overcomes the shortcoming of unobvious thermal population of thermally coupled levels in low temperature range through traditional Boltzmann distributing method.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Energy transfer process between host and Ho<SUP>3+</SUP> was analyzed. </LI> <LI> Temperature dependent emission spectra of Ho<SUP>3+</SUP> doped Y<SUB>2</SUB>WO<SUB>6</SUB> were studied. </LI> <LI> A new method to achieve optical thermometry through manipulating the energy transfer from WO<SUB>6</SUB> <SUP>6−</SUP> to Ho<SUP>3+</SUP> is proposed. </LI> </UL> </P>
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Yanyan Shi,Meng Wang,Minghui Shen,Haiming Wang 대한기계학회 2015 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.29 No.7
To obtain the phase fraction and velocity of vertical air-water two-phase flows, an electromagnetic flowmeter with two arc-shapedelectrodes is proposed. The electromagnetic flowmeter is operated in two measuring modes: electrical measurement mode and electromagneticmeasurement mode. The geometry of the electromagnetic flowmeter for dual-parameter measurement is optimized based onthe numerical finite element analysis. The electric field and sensitivity distribution of the electromagnetic flowmeter is investigated toensure an accurate measurement of volume fraction under the mode of the electrical measurement. Weight function of the electromagneticflowmeter operated under the mode of the electromagnetic measurement is also analyzed for the velocity measurement. Preliminaryexperiments are conducted to calibrate the optimized electromagnetic flowmeter in simulated air-water flows. It is noted that the proposedelectromagnetic flowmeter with arc-shaped electrodes can be adopted to obtain the phase fraction and velocity of vertical air-watertwo-phase flows.
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Wang, Xiangfu,Bu, Yanyan,Yan, Xiaohong,Cai, Peiqing,Wang, Jing,Qin, Lin,Vu, Thiquynh,Seo, Hyo Jin OPTICAL SOCIETY OF AMERICA 2016 Optics letters Vol.41 No.22
<P>Understanding site-selective fluorescence is one of valuable importance for spectrum modulation. In this Letter, we observed the existence of two non-equivalent Gd-activated crystallographic sites in an Er3+-doped hexagonal Na1.5Gd1.5F6 phosphor. It is proved that two green emissions from the S-4(3/2) level separately originate from the Gd1 (540 nm) and Na2/Gd2 (550-555 nm) crystallographic sites, and the 657 nm red emission from the F-4(9/2) level only originates from Na2/Gd2 site through using the time-resolved luminescence spectra. The 142.2% absolute enhancement of the red emission is realized through the synergistic effect of ultraviolet downconversion and infrared upconversion induced by the 370 nm and 1.54 mu m dual-mode excitation. (C) 2016 Optical Society of America</P>
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Guoyong Wang,Yanyan Zhu,Yunhui Zhai,Wanxu Wang,Zhiping Du,Jieqiong Qin 한국공업화학회 2017 Journal of Industrial and Engineering Chemistry Vol.47 No.-
A simple process to synthesize polyglycerol modified polysiloxane surfactants has been carried outapplying a “grafting-to” approach. After formation of allyl polyglycerol ether (APGE) from diglycerol(DGY) and allyl glycidyl ether (AGE), polysiloxane modified by designed number of polyglycerol groups(PHMS-APGE) were obtained by connecting the APGE structure to different Si H functionalizedpolyhydromethyl siloxane (PHMS). The synthesized APGE-PHMS were characterized by IR and 1H NMR. Solubility measurements showed that the solubility of the as-prepared polymers increased in polarsolvents with the increasing of the amount of hydrophilic APGE groups. Furthermore, the surface activity,surface adsorption, aggregation and spreading behaviors of APGE-PHMS were investigated utilizingsurface tension measurements, dynamic light scattering (DLS), transmission electron microscopy (TEM)and contact angle measurements. The results showed that critical aggregation concentration (CAC) andthe time needed to reach adsorption equilibrium on water surface decrease systematically with theincrease in the number of APGE groups. These polymers in aqueous solutions could aggregate to formspherical assemblies. Moreover, the spreading behavior of these polymers on low energy surface wasfound to be influenced by the number of hydrophilic APGE groups.
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Zhu Yanyan,Tang Wei,Tang Xiaofeng,Wang Lihuan,Li Wei,Zhang Qian,Li Mingzhang,Fang Congbing,Liu Yongsheng,Wang Songhu 한국식물생명공학회 2021 Plant biotechnology reports Vol.15 No.5
Colchicine-induced polyploidization has been extensively utilized in plant-breeding programs to increase biomass and overall yield of various crop species. Chromosome doubling usually increases the plant size and cell size. However, the underly- ing mechanisms remain elusive. In this study, we showed that 0.1% colchicine is an optimized concentration for inducing tetraploidization of Actinidia chinensis var. chinensis ‘Hongyang’, a commercially important diploid kiwifruit cultivar. The tetraploid plants showed increased plant height, leaf size, and biomass, as compared with the corresponding diploid plants. Scanning electron microscopy and histological analysis indicated that the leaf cell size was significantly increased in the tetraploid plants. Our further transcriptome analysis revealed the 5922 differentially expressed genes between the diploid and tetraploid plants. Gene Ontology analysis enriched the cell wall-related genes, including the pectin methylesterases (PMEs) and expansins (EXPs), both of which play a critical role in cell wall loosening and extension. The increased expression of PME and EXP genes might contribute to the increased cell size in the tetraploid plants. Together, our work indicated that tetraploidization increases the organ and cell size in kiwifruit, possibly by enhancing the cell wall extensibility.
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The Correlation between Thyrotropin and Dyslipidemia in a Population-based Study
Li Lu,Beibei Wang,Zhongyan Shan,Fengwei Jiang,Xiaochun Teng,Yanyan Chen,Yaxin Lai,Jiani Wang,Haibo Xue,Sen Wang,Chenyan Li,He Liu,Ningna Li,Jiashu Yu,Liangfeng Shi,Xin Hou,Qian Xing,Xue Bai,Weiping Te 대한의학회 2011 Journal of Korean medical science Vol.26 No.2
This study investigated the relationship between serum thyrotrophin levels and dyslipidemia in subclinical hypothyroid and euthyroid subjects. A total of 110 subjects with subclinical hypothyroidism and 1,240 euthyroid subjects enrolled in this study. Patients with subclinical hypothyroidism had significantly lower high density lipoprotein cholesterol (HDL-C) levels than those who were euthyroid. The lipid profiles were each categorized and mean thyrotrophin levels were higher in subjects in the dyslipidemia subclasses than subjects in the normal subclasses. Thyrotrophin was positively associated with serum triglyceride and negatively associated with serum HDL-C in women. Thyrotrophin was also positively associated with total cholesterol (TC) in the overweight population along with TC and LDL-C in overweight women. In the euthyroid population, thyrotrophin was positively associated with TC in the overweight population. In conclusion, serum thyrotrophin was correlated with dyslipidemia in subclinical hypothyroid and euthyroid subjects; the correlation was independent of insulin sensitivity.
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Jing Li,Xiaochun Teng,Weiwei Wang,Yanyan Chen,Xiaohui Yu,Shen Wang,Jianxin Li,Lin Zhu,Chenyan Li,Chenling Fan,Hong Wang,Hongmei Zhang,Weiping Teng,Zhongyan Shan 한국식품영양과학회 2011 Journal of medicinal food Vol.14 No.5
Soy and its isoflavones have been suggested to suppress thyroperoxidase (TPO), induce goiter, inhibit deiodinase, and modulate immune functions. This study initially investigated the effects of dietary soy consumption on maternal thyroid functions and anti-TPO antibody (TPOAb) production during early pregnancy. Data were collected through questionnaire from 505 women enrolled during early pregnancy by random sampling in Shenyang, China. Based on soy intake frequency, the subjects were divided into three groups (frequent [three or more times per week], conventional [more than twice per month but less than three times per week], and occasional [two or fewer times per month]). Serum thyrotropin (TSH), free thyroxine (FT_4), and TPOAb were measured by chemiluminescence immunoassay. Additionally, the concentrations of two primary isoflavones (daidzein and genistein) and creatinine were assessed in the spot urine samples from representative subjects (about 20%) randomly selected from the three groups. The percentages of frequent, conventional, and occasional consumers were 18.6%, 62.6%, and 18.8%, respectively. No difference was found in age, medical records, family history of thyroid diseases, serum FT_4, TSH, and TPOAb levels, TPOAb-positive percentages, or prevalence of thyroid dysfunctions among the groups. Both urinary daidzein and genistein levels were significantly higher in the frequent consumers compared with the other two groups. No correlations were found between urinary isoflavone levels and serum FT_4 or TSH. Urinary isoflavone levels were not significantly different between TPOAb-positive and -negative women among the randomly selected representative subjects. On the whole, our findings suggest dietary soy consumption during early pregnancy is not associated with the development of thyroid dysfunction or autoimmunity.
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Li, Fu,Cao, Yufeng,Luo, Yanyan,Liu, Tingwu,Yan, Guilong,Chen, Liang,Ji, Lilian,Wang, Lun,Chen, Bin,Yaseen, Aftab,Khan, Ashfaq A.,Zhang, Guolin,Jiang, Yunyao,Liu, Jianxun,Wang, Gongcheng,Wang, Ming-Kui The Korean Society of Ginseng 2019 Journal of Ginseng Research Vol.43 No.4
Background: The leaves and roots of Panax ginseng are rich in ginsenosides. However, the chemical compositions of the leaves and roots of P. ginseng differ, resulting in different medicinal functions. In recent years, the aerial parts of members of the Panax genus have received great attention from natural product chemists as producers of bioactive ginsenosides. The aim of this study was the isolation and structural elucidation of novel, minor ginsenosides in the leaves of P. ginseng and evaluation of their antiinflammatory activity in vitro. Methods: Various chromatographic techniques were applied to obtain pure individual compounds, and their structures were determined by nuclear magnetic resonance and high-resolution mass spectrometry, as well as chemical methods. The antiinflammatory effect of the new compounds was evaluated on lipopolysaccharide-stimulated RAW 264.7 cells. Results and conclusions: Two novel, minor triterpenoid saponins, ginsenoside $LS_1$ (1) and 5,6-didehydroginsenoside $Rg_3$ (2), were isolated from the leaves of P. ginseng. The isolated compounds 1 and 2 were assayed for their inhibitory effect on nitric oxide production in LPS-stimulated RAW 264.7 cells, and Compound 2 showed a significant inhibitory effect with $IC_{50}$ of $37.38{\mu}M$ compared with that of NG-monomethyl-L-arginine ($IC_{50}=90.76{\mu}M$). Moreover, Compound 2 significantly decreased secretion of cytokines such as prostaglandin $E_2$ and tumor necrosis factor-${\alpha}$. In addition, Compound 2 significantly suppressed protein expression of inducible nitric oxide synthase and cyclooxygenase-2. These results suggested that Compound 2 could be used as a valuable candidate for medicinal use or functional food, and the mechanism is warranted for further exploration.
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