A Novel Vibration Model for Explanation of the Frequency Features in Multistage Wind Turbine Gearboxes Considering the Effects of Inter-stage Meshing Frequency Modulation

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.

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.

Characterization of Extended-Spectrum β-Lactamase Genes of Shigella flexneri Isolates With Fosfomycin Resistance From Patients in China

Yanyan Liu,Yue Cheng,Haifei Yang,Li-Fen Hu,Jun Cheng,Ying Ye,Jia-Bin Li 대한진단검사의학회 2017 Annals of Laboratory Medicine Vol.37 No.5

Background: The emergence of fosfomycin resistance and extended-spectrum β-lactamase (ESBL) genes is a serious threat to public health and a new challenge in shigellosis treatment. The purpose of this study was to identify fosfomycin resistance and characterize β-lactamase genes in fos-carrying isolates of Shigella flexneri from patients in China. Methods: A total of 263 S. flexneri isolates were collected from 34 hospitals in the Anhui Province of China during September 2012-September 2015 and screened for fosA3, fosA, and fosC2 by PCR amplification and sequencing. The fos-carrying isolates were then screened for β-lactamase genes. The clonal relationships between fosA3-carrying isolates, the transmissibility of fosfomycin resistance, replicon types of plasmids carrying fosfomycin resistance genes and other associated resistance genes were investigated. Results: Twenty-five of the 263 isolates (9.5%) showed resistance to fosfomycin, and 18 (6.8%) were positive for fosA3. None of the isolates was positive for fosA or fosC2. Seventeen of the isolates carrying fosA3 (94%) were CTX-M producers (seven CTX-M-55, five CTX-M-14, and five CTX-M-123), while three (16.7%) were TEM producers (TEM-1).Sixteen (88.9%) fosA3-carrying isolates exhibited multi-drug resistance. The replicon types of the 13 fosA3-carrying plasmids were IncF (n=13), IncHI2 (n=3), IncIl-Ir (n=2), and IncN (n=1). Conclusions: Our results indicated that fosA3 could spread through plasmids in S. flexneri isolates, along with the blaCTX-M and blaTEM, which facilitate its quick dispersal. To the best of our knowledge, this is the first report of CTX-M-123-type ESBLs in S. flexneri isolates from patients in China.

Numerical Simulation of Hydraulic Fracture Propagation within Fractured Shale Gas Reservoir Based on a Three-dimensional Fracture Network Model

( Yanyan Li ),( Yanjun Shang ),( Lihui Li ) 대한지질공학회 2019 대한지질공학회 학술발표회논문집 Vol.2019 No.2

This research presents coupled hydro-mechanical modeling of hydraulic fracturing processes within fractured reservoir based on a three-dimensional fracture network model. Field investigation was conducted to collect joint data from shale outcrops of the Yanchang Formation using the window sampling method. A three-dimensional joint network model was built using the Monte Carlo simulation method. Lamina data were collected from conventional logging, borehole TV and cores. The Monte Carlo method was also used to model artificial laminas. The fracture network model was built by adding the artificial laminas to the joint network model. The interactions between hydraulic fractures and natural fractures are analyzed, providing a better insight into the performance of hydraulic fracturing jobs in naturally fractured reservoir. Numerical results show that the hydraulic fracture may arrest, cross, or divert into natural fractures depending on the rock mechanical properties, direction of rock principal stresses, and fracture intersection angle. The propagation direction of hydraulic fractures is controlled the maximum horizontal stress. Laminas change the propagation direction of hydraulic fractures, suggesting that the heterogeneity of shale influences the propagation of hydraulic fractures. The influence of the injection rate of fracturing fluid on the propagation of hydraulic fractures was studied. The results show that there is only one major hydraulic fracture when the injection rate is 0.1 ㎥ per minute. With the increase of the injection rate, several major hydraulic fractures perpendicular to laminas were produced, improving the fracture complexity and expanding the reservoir drainage area.

Regulation Mechanism of Peptides Derived from Sea Cucumber (Apostichopus japonicas) for Modulation of Learning and Memory

Yanyan Li,Jing Shang,Zhenzhou Jiang,Luyong Zhang,Xiurong Su 한국식품과학회 2016 Food Science and Biotechnology Vol.25 No.1

Peptides derived from the sea cucumber Apostichopus japonicas have immunomodulatory and antioxidant activities. Three dosage levels of peptide hydrolysates were fed to Institute of Cancer Research (ICR) mice. Standardized Y and Morris water mazes were used to determine the effects of A. japonicas peptides on learning and memory. All 3 mouse test groups showed reductions in the latency period (LP), the number of times that a mouse swam over the location of a platform (NCP), the ratio of the distance from a target quadrant to the total swimming distance (DTQ), and the time spent in the target quadrant (TTQ). Microarray analysis was then carried out and 308 genes were differentially expressed between groups, of which 235 were up and 73 were down regulated in the brains of test group animals, compared with control group animals. Expressions of genes identified in microarrays were then analyzed using qRT-PCR.

Phenomenological Modeling of Vibration Signal and Analyzing of Modulation Mechanisms in Multi-Stage Wind Turbine Gearboxes

Yanyan Nie,Jianfeng Li,Liming Wang,Fangyi Li 대한기계학회 2023 대한기계학회 춘추학술대회 Vol.2023 No.11

How could firms benefit more from absorptive capacity under technological turbulence? The contingent effect of managerial mechanisms

Li Yanyan,Kwok Ron Chi-Wai,Zhang Shanshan,Gao Shanxing 기술경영경제학회 2020 ASIAN JOURNAL OF TECHNOLOGY INNOVATION Vol.28 No.1

Based on the knowledge-based view, this paper examines how firms can achieve an enhanced new product performance from the absorptive capacity under technological turbulence. By examining 165 Chinese pharmaceutical firms' data, this paper found that under technological turbulence, the benefits of absorptive capacity on new product performance will decrease; however, if firms maintain complementary managerial mechanisms (technological environmental scanning mechanism and coordination mechanism in this paper), the decrease effect of technological turbulence could be mitigated. Theoretically, the negative moderating effect of technological turbulence extends the investigation of the under assumptions of absorptive capacity and enriches the research on the contingency context of ACAP. Moreover, the examination of the alleviation effect regarding the managerial mechanisms responds to the scholar's appeals for more research focusing on management factors in absorptive capacity and product development research. The results also highlight the managerial-environment fit in the new product development area. Practically, this paper offers managerial implications for managers: they should focus more attention on technological breakthroughs so as to prepare early for any potential uncertainties and opportunities; moreover, managers could cultivate the managerial mechanisms to enhance knowledge monitoring and sharing activities, which could be utilised to buffer the uncertainty and update the firm's ACAP.

Screening of key miRNAs related with the differentiation of subcutaneous adipocytes and the validation of miR-133a-3p functional significance in goats

Li Xin,Zhang Hao,Wang Yong,Li Yanyan,Wang Youli,Zhu Jiangjiang,Lin Yaqiu 아세아·태평양축산학회 2023 Animal Bioscience Vol.36 No.1

Objective: Adipocyte differentiation is regulated by a variety of functional genes and noncoding RNAs. However, the role of miRNAs in lipid deposition of goat white adipose tissue is still unclear. Therefore, this study revealed the miRNA expression profile in goat subcutaneous adipocytes by sRNA-seq. Methods: The miRNA expressed in goat subcutaneous preadipocytes and the mature adipocytes were sequenced by sRNA-seq. The differentially expressed miRNAs (DEm) were screened and gene ontology (GO) and Kyoto encyclopedia for genes and genomes (KEGG) analyses were performed. Gain-of-function and loss-of-function combined with oil red O staining, Bodipy staining, and quantitative reverse-transcription polymerase chain reaction (qPCR) were utilized to determine the effect of miR-133a-3p on adipocyte differentiation. Results: A total of 218 DEm were screened out. The target genes of these DEm were significantly enriched in GO items such as biological regulation and in KEGG terms such as FAK signaling pathway and MAPK signaling pathway. qPCR verified that the expression trend of miRNA was consistent with miRNA-seq. The gain-of-function or loss-of-function of miR-133a-3p showed that it promoted or inhibited the accumulation of lipid droplets, and CCAAT enhancer binding protein α (C/EBPα) and C/EBPβ were extremely significantly up-regulated or down-regulated respectively (p<0.01), the loss-of-function also led to a significant down-regulation of peroxisome proliferator activated receptor gamma (PPARγ) (p<0.01). Conclusion: This study successfully identified miRNAs expression patterns in goat subcutaneous adipocytes, and functional identification indicates that miR-133a-3p is a positive regulator of the differentiation process of goat subcutaneous adipocytes. Our results lay the foundation for the molecular mechanism of lipid deposition in meat-source goats from the perspective of miRNA.

fects of Dietary Soy Intake on Maternal Thyroid Functions and Serum Anti-Thyroperoxidase Antibody Level During Early Pregnancy

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.

Transcriptome analysis of colchicine-induced tetraploid Kiwifruit leaves with increased biomass and cell size

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.