Design and Study on Dynamic Measuring System for Field Surface Roughness

Lv Xiao-rong,Lv Xiao-lian,Zhang Li-hua 보안공학연구지원센터 2016 International Journal of Signal Processing, Image Vol.9 No.1

In order to explore the adaptability and relationship of planter to field surface roughness, dynamic simulated testing was carried out on working performance of the designed direct seeding machine in field. The designed dynamic testing system of field surface roughness is composed of the roughness test devices, two angular displacement sensors, data acquisition card and computer, etc.. Through field test, the two types of field surface roughness were detected on the original field surface roughness formed by the working chassis and the field surface roughness formed after planters work. The signals during testing were analyzed in time-domain and frequency-domain by using Matlab software. The transfer functions of the system were established, and the dynamic characteristics of the system were analyzed. The results show that, the system is a linear one with the typical first order feature. The dynamic characteristics of the systems such as response speed, frequency bandwidth and thickness of covering soil and other performance indicators are able to meet the requirements of agricultural technology. The studied results provide a new method to explore the adaptability of the planter for field surface roughness, and provide technical references to study the overburden soil performance of the planter.

Phytochemistry and pharmacology of natural prenylated flavonoids

Hua-Wei Lv,Qiao-Liang Wang,Meng Luo,Meng-Di Zhu,Hui-Min Liang,Wen-Jing Li,Hai Cai,Zhong-Bo Zhou,Hong Wang,Sheng-Qiang Tong,Xing-Nuo Li 대한약학회 2023 Archives of Pharmacal Research Vol.46 No.4

Prenylated flavonoids are a special kind of flavonoid derivative possessing one or more prenyl groups in the parent nucleus of the flavonoid. The presence of the prenyl side chain enriched the structural diversity of flavonoids and increased their bioactivity and bioavailability. Prenylated flavonoids show a wide range of biological activities, such as anti-cancer, anti-inflammatory, neuroprotective, anti-diabetic, anti-obesity, cardioprotective effects, and anti-osteoclastogenic activities. In recent years, many compounds with significant activity have been discovered with the continuous excavation of the medicinal value of prenylated flavonoids, and have attracted the extensive attention of pharmacologists. This review summarizes recent progress on research into natural active prenylated flavonoids to promote new discoveries of their medicinal value.

Design of Open Language Laboratory Information System in Network Environment

Hua Lv,Mei Ling Jiang,Cheng Shuang Han 보안공학연구지원센터 2015 International Journal of Smart Home Vol.9 No.7

College language lab is “the second classroom” of foreign language teaching. It is a place of effectively cultivating students' ability of self-learning and practicing. This paper analyzes the significance and role of the language laboratory for cultivating students' self-learning and innovation ability, designs out the model of function structue for the openning of the language laboratory, proposes the form of database design, and discusses the system architecture.

Investigation of plasma electrolytic oxidation process on AZ91D magnesium alloy

Guo-Hua Lv,Huan Chen,Li Li,Er-Wu Niu,Huan Pang,Bin Zou,Si-Ze Yang 한국물리학회 2009 Current Applied Physics Vol.9 No.1

Ceramic coatings oxidized for different time periods were prepared to characterize the plasma electrolytic oxidation (PEO) process of AZ91D magnesium alloy. The coatings were analyzed using scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscope and potentiodynamic polarization measurement. The results show that the PEO coatings perform different growth behaviors at different PEO stages, and different morphologies are exhibited on α- and β-phase of Mg substrate. The corrosion resistance measurement predicates that within the first 30 min oxidation, coating oxidized for 20 min is the best corrosion resistant. Ceramic coatings oxidized for different time periods were prepared to characterize the plasma electrolytic oxidation (PEO) process of AZ91D magnesium alloy. The coatings were analyzed using scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscope and potentiodynamic polarization measurement. The results show that the PEO coatings perform different growth behaviors at different PEO stages, and different morphologies are exhibited on α- and β-phase of Mg substrate. The corrosion resistance measurement predicates that within the first 30 min oxidation, coating oxidized for 20 min is the best corrosion resistant.

Evaluation of Bending Fatigue Testing of Austempered Ductile Iron Spur Gears

Jian Hua Lv(려건화),Rui Zhou(주서),Yang Xu(허양),Zhen Qin(진진),Qi Zhang(장기),Sungki Lyu(류성기) 한국기계가공학회 2020 한국기계가공학회지 Vol.19 No.12

An experimental evaluation of bending fatigue strength for austempered ductile iron (ADI) spur gears was performed using a Zwick fatigue tester. The gear material was manufactured using vertical continuous casting, resulting in the radius of the graphite grains being smaller. The stress-number of cycles curve (S-N curve) for the bending fatigue strength of the ADI spur gears thus manufactured, without any specific surface treatments, was obtained using post-processing software. It was observed that when the reliability was 50%, the allowable root stress was 610 MPa. was calculated using an analytical method as well as the finite element method, and the difference between the values calculated using the two methods is only 7%. This study provides a reliable basis to rate the reliability design of small gearboxes in automation in the future.

Metallothionein cDNA Cloning and Metallothionein Expression in Sea Cucumber (Apostichopus japonicus, Slenka) from the WeiHai Coast of China

Xinfang Lv,Xinfang Lv,Xinfang Lv,Zhaoyang Hua 한국해양과학기술원 2018 Ocean science journal Vol.53 No.4

The aims of this work were (1) the identification of the metallothionein (MT) gene cDNA sequence in Apostichopus japonicus and (2) the quantification of MT mRNA expression in the intestine, body wall and respiratory tree of A. japonicas after exposure to cadmium or zinc. Using RT-PCR and RACE-PCR, we cloned the MT complete cDNA sequence of A. japonicus using the RNA extracted from Cadmium-exposed intestines. The 1351 bp MT cDNA consisted of a 126 bp 5’ untranslated region, a 1069 bp 3’ untranslated region, and a 156 bp open reading frame coding for 51 amino acids, including 16 cysteines. The MT sequence of A. japonicus was 47% identical to the sequence of MT from Strongylocentrotus purpuratus. Through real-time quantitative PCR analysis, we found that the MT expression levels were significantly higher when the specimens were exposed to heavy metals, and the response to combined metal ions exposure occurred earlier than that for single metal ion exposure. Additionally, the induction of MT transcription was more responsive to zinc and can be envisaged as a potential biomarker for zinc contamination.

Effects of graphite additives in electrolytes on the microstructure and corrosion resistance of Alumina PEO coatings

Guo-Hua Lv,Huan Chen,Wei-Chao Gu,Wen-Ran Feng,Li Li,Er-Wu Niu,Xian-Hui Zhang,Si-Ze Yang 한국물리학회 2009 Current Applied Physics Vol.9 No.3

In the present work, graphite grains of different sizes were added into the electrolyte to prepare ceramic coatings on aluminum by plasma electrolytic oxidation (PEO). Scanning electron microscopy (SEM) coupled with an energy dispersive X-ray analysis system (EDX), Raman spectroscopy and X-ray diffractometer (XRD) were used to characterize the coatings. A three-electrode system was used to evaluate the corrosion performances of the coatings in a 3.5 wt.% NaCl solution. It was found that the morphology and corrosion performance of the coatings were significantly influenced by the size of the graphite grains. Compared with bigger graphite grains, finer ones were involved in the oxidation process and embedded within the ceramic coatings, which made the coatings less porous and more compact. Thus, the corrosion resistance of the coatings with embedded graphite grains was greatly improved. In the present work, graphite grains of different sizes were added into the electrolyte to prepare ceramic coatings on aluminum by plasma electrolytic oxidation (PEO). Scanning electron microscopy (SEM) coupled with an energy dispersive X-ray analysis system (EDX), Raman spectroscopy and X-ray diffractometer (XRD) were used to characterize the coatings. A three-electrode system was used to evaluate the corrosion performances of the coatings in a 3.5 wt.% NaCl solution. It was found that the morphology and corrosion performance of the coatings were significantly influenced by the size of the graphite grains. Compared with bigger graphite grains, finer ones were involved in the oxidation process and embedded within the ceramic coatings, which made the coatings less porous and more compact. Thus, the corrosion resistance of the coatings with embedded graphite grains was greatly improved.

Design of 2-DOF decoupled large stroke precision positioning platform

Hua-wei Ji,Bo Lv,Tian-yi Li,Fan Yang,An-qi Qi,Xin Wu,Jing Ni 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.12

Aiming at the problem that the output displacement of the piezoelectric actuator is small and the coupling motion of the positioning platform affects the positioning accuracy, we designed a 2-DOF decoupling large-stroke precision positioning platform. First, a dynamic model based on the lumped mass method was established and verified by simulation. The multi-objective genetic optimization algorithm was used to optimize the structural size parameters of the positioning platform, and the optimal solution set of the structural size parameters of the positioning platform was obtained. Finally, according to the theoretical and simulation results, a prototype was fabricated and the working stroke, decoupling performance and natural frequency were tested experimentally. The results show the coupling rates between axes of the positioning platform in the x-direction and y-direction are 1.31 % and 1.62 %, respectively, the natural frequency is 337.2 Hz, and the positioning stroke is 89.2 μm×85.9 μm. The positioning platform designed in this paper is decoupled and has a large output stroke.

Implementation of online model updating with ANN method in substructure pseudo-dynamic hybrid simulation

Yan Hua Wang,Jing Lv,Yan Feng,Bo Wen Dai,Cheng Wang,Jing Wu,Zi Yan Chen 국제구조공학회 2021 Smart Structures and Systems, An International Jou Vol.28 No.2

Substructure pseudo-dynamic hybrid simulation (SPDHS) is an advanced structural seismic testing method which combines physical experiment and numerical simulation. Generally, the key components which display nonlinearity first are taken as experimental substructures for actual test, and the remaining parts are modeled in simulation. Model updating techniques can be effectively applied to enhance the model precision of nonlinear numerical elements. Specifically, the constitutive model of the experimental substructure is identified online by the instantaneously-measured data, and the corresponding numerical elements with similar hysteretic behaviors are updated synchronously. Artificial neural network (ANN) can recognize the system which cannot be represented by definite numerical model, and thus avoids the structural response distortion caused by the inherent numerical model defects. In this study, a framework for online model updating in SPDHS with ANN method is expanded to implement actual test validation. Moreover, the effectiveness of ANN method is demonstrated by practical tests of a two-story frame model with bending dampers. Additionally, the unscented Kalman filter technique and offline ANN identification approach are both examined in the test validation. The experimental results show that, under the identical loading history, the online ANN method can significantly reduce the model errors and improve the accuracy of SPDHS.

miR167c is Induced by High Alkaline Stress and Inhibits Two Auxin Response Factors in Glycine soja

Dekang Lv,Ying Ge,Bei Jia,Xi Bai,Peihua Bao,Hua Cai,Wei Ji,Yanming Zhu 한국식물학회 2012 Journal of Plant Biology Vol.55 No.5

Soil alkalinity is one of the major environmental factors limiting crop productivity worldwide. MicroRNAs (miRNAs) are small (21-25 nucleotides) single-stranded non-coding RNAs that regulate developmental and stress responses in plants by cleaving target mRNAs. However,little is known about the role of miRNAs in the response to alkaline stress. In this study, we identified the miR167c as a high alkaline-responsive miRNAs in wild soybean based on genome microarray and RNA gel blot. The presence of a cisacting abscisic acid (ABA) responsive element (ABRE) in the upstream region and the ABA inducement of primiR167c suggested that miR167c might be regulated by ABA. We also showed that two auxin response factors (ARF),Gs14g03650 and Gs18g05330, were target genes of the alkaline-inducible miR167c and rapidly down-regulated following alkaline treatment. Our results reveal that miR167c regulated the expression pattern of ARFs, which could be vital for both development and stress adaptation.