Study on the Reduction of Gear Whine Noise in Diesel Engine Gear Train

Qi Zhang(장기),Yong Bo Wang(왕용보),Jian Hua Lv(려건화),Zhong Gang Zhu(주중강),Zhen Qin(진진),Sung Ki Lyu(류성기) Korean Society for Precision Engineering 2019 한국정밀공학회지 Vol.36 No.9

Noise, Vibration and Harshness (NVH) is a comprehensive issue of manufacturing quality that gives the purchaser a superficial feeling. The NVH performance of the vehicle has undoubtedly become an important factor and basis for consumers. When the internal combustion engine is working, it generates a strong noise thus making it necessary to reduce the vibration and noise. The noise of diesel engine is divided into acoustic and structural radiation noise according to different radiation paths. The structure radiated noise is mainly caused by the combustion noise and mechanical transmission noise, while mechanical transmission noise is mainly generated by the meshing gears in the diesel. This paper aims to solve the problem of a diesel engine abnormal gear whine noise under idling conditions with a combination of simulation and experiment. By gear micro-modification, the gear train whine noise is reduced by minimizing the PPTE of the gear train. The comparison of the simulation to benching testing shows a good correlation. It provides an optional solution to the modification proposal of the engine gear train, which uses the similar structure for the engine. Future work will dwell on a better understanding of the gear rattle noise, which will be discussed later.

Angiopoietin-1 and Angiopoietin-2 Expression Imbalance Influence in Early Period After Subarachnoid Hemorrhage

Hua Gu,Zhen-Hai Fei,Yi-Qi Wang,Jian-Guo Yang,Chao-Hui Zhao,Yong Cai,Xing-Ming Zhong 대한배뇨장애요실금학회 2016 International Neurourology Journal Vol.20 No.4

Purpose: Microvascular endothelial integrity is important for maintaining the blood-brain barrier (BBB). However, subarachnoid hemorrhage (SAH) disrupts this integrity, making the BBB dysfunctional—an important pathophysiological change after SAH. Angiopoietin-1 (Ang-1) and angiopoietin-2 (Ang-2) regulate microvascular permeability by balancing each other’s expression. Methods: This study investigated the dynamics of Ang-1 and Ang-2 expression after SAH and the protective effect of Ang-1 on BBB functioning using an endovascular puncture model of rat SAH. The Ang-1 and Ang-2 expression in brain tissue was determined by immunohistochemistry. In addition, Western blotting was used to estimate Ang-1 and Ang-2 concentration and to compare them at 6–72 hours post-SAH cortex and hippocampus. Evans blue viability assay was used to evaluate BBB permeability, and neurological testing was implemented to evaluate neurological impairment during SAH. Results: It was found that following SAH, Ang-1 expression decreases and Ang-2 expression increases in the cortex, hippocampus, and microvessels. The Ang-1/Ang-2 ratio decreased as quickly as 6 hours after SAH and reached its lowest 1 day after SAH. Finally, it was found that exogenous Ang-1 reduces SAH-associated BBB leakage and improves neurological function in post-SAH rats. Conclusions: Our findings suggest that the equilibrium between Ang-1 and Ang-2 is broken in a period shortly after SAH, and the treatment of exogenous Ang-1 injection alleviates neurological dysfunctions through decreasing BBB destruction.

Simulation and Experimental Analysis for Noise Reduction of a Scooter Gearbox

Qi Zhang(장기),Jing Zhang(장정),Zhong Hua Liu(유충화),Jian Hua Lv(려건화),Zhen Qin(진진),Sung Ki Lyu(류성기) Korean Society for Precision Engineering 2018 한국정밀공학회지 Vol.35 No.8

Nowadays, noise, vibration, and harshness (NVH) is a comprehensive issue related to manufacturing quality, it gives the purchaser the most direct and superficial feeling. Following economic development, the improvement of people’s living standards, and the expansion of the export market, it has become urgent to develop and produce some better NVH performance motorcycles. In this paper, the transmission of a scooter gearbox is modeled and analyzed by software. Then, the first helical gear pair of the gearbox was investigated through static analysis. Lastly, optimized modification was verified using B&K testing equipment in the semi-anechoic room. The comparison of the simulation to prototype during testing showed a good correlation, which means simulation optimization can greatly improve the research and development efficiency of the transmission system.

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.

Design and Expression of Recombinant Antihypertensive Peptide Multimer Gene in Escherichia coli BL21

Sheng Qi Rao,Yu Jie Su,Jun Hua Li,Zhen Zhen Xu,Yan Jun Yang 한국미생물 · 생명공학회 2009 Journal of microbiology and biotechnology Vol.19 No.12

Simulation Analysis of Flexible Track Drilling Machines Based on ADAMS

Zhong-gang Zhu(주중강),Qi Zhang(장기),Jian-Hua Lv(려건화),Zhen Qin(진진),Sung-Ki Lyu(류성기) 한국기계가공학회 2018 한국기계가공학회지 Vol.17 No.5

Flexible track drilling machines are credited with important applications in the area of aircraft manufacturing because of their portability, quick installation capabilities, and high efficiency. However, their structures are special and the constitution principles and motion characteristics are difficult to control, increasing the development costs and research cycle in the context of the technology blockade of foreign companies. The simulation analysis of flexible track drilling machines can be conducted by applying virtual prototypes, shortening the development cycle and reducing the cost. In this paper, a model of a machine is established by using the SolidWorks software and imported into ADAMS to conduct kinematic and dynamic simulation analysis. During the analysis, the feasibility of the configuration is checked, a reasonable driving motion is chosen, potential deficiencies are found, and improvement actions are raised.

Bone Formation in Ectopic and Osteogenic Tissue Induced by a Novel BMP-2-related Peptide Combined with Rat Tail Collagen

Jing-Feng Li,Zhen-Yu Lin,Qi-Xin Zheng,Xiao-Dong Guo,Shu-Hua Yang,Hong-Wei Lu,Sheng-Hui Lan 한국생물공학회 2010 Biotechnology and Bioprocess Engineering Vol.15 No.5

Bone morphogenetic proteins (BMPs) play an important role in regulating osteoblast differentiation and subsequent bone formation, mainly evidenced by the induced osteogenic ability of BMP-2 from BMPs. However, BMP-2 alone does not induce the expected efficacy due to its short retention in vivo. In this study, a novel BMP-2-related peptide (designated P24) derived from the “knuckle epitope”of BMP-2 was coupled covalently to type I collagen derived from rat tail and observed under scanning electron microscopy (SEM) in low vacuum mode. The BMP-2-related peptide/collagen composite was implanted in vivo into the pocket of the quadriceps musculature of Sprague-Dawley (SD) rats and then harvested 3 or 6 weeks after surgery. It was found that lyophilized collagen retained a porous network structure with an average inner-diameter of 90 ~ 160 μm. Based on radiographic evaluation and histological examination, BMP-2-related peptide/collagen induced significant ectopic bone formation compared to that of rat tail collagen alone as a control. Our results indicate collagen served as a good carrier for newly synthesized BMP-2-related peptide and that the BMP-2-related peptide/collagen composite was an effective substitute in bone tissue engineering.

Effects of Myogenin on Expression of Late Muscle Genes through MyoD-Dependent Chromatin Remodeling Ability of Myogenin

Chao Du,Ju-Hua Ni,Ya-Qiong Jin,Jun-Juan Qi,Zhen-Xing Ji,Shu-Yan Li,Guo-Shun An,Hong-Ti Jia 한국분자세포생물학회 2012 Molecules and cells Vol.34 No.2

MyoD and myogenin (Myog) recognize sets of distinct but overlapping target genes and play different roles in skeletal muscle differentiation. MyoD is sufficient for near-full expression of early targets, while Myog can only partially enhance expression of MyoD-initiated late muscle genes. However, the way in which Myog enhances the expression of MyoD-initiated late muscle genes remains unclear. Here, we examine the effects of Myog on chromatin remodeling at late muscle gene promoters and their activation within chromatin environment. Chromatin immunoprecipitation (ChIP) assay showed that Myog selectively bound to the regulatory sequences of late muscle genes. Overexpres-sion of Myog was found to overcome sodium butyrate-inhibited chromatin at late muscle genes in differ-entiating C2C12 myoblasts, shifting the transcriptional activation of these genes to an earlier time period. Furthermore, overexpression of Myog led to increased hyperacetylation of core histone H4 in differentiating C2C12 myoblasts but not NIH3T3 fibroblasts, and hyperacetylated H4 was associated directly with the late muscle genes in differentiating C2C12, indicating that Myog can induce chromatin remodeling in the presence of MyoD. In addition, co-immunopre-cipitation (CoIP) revealed that Myog was associated with the nuclear protein Brd4 in differentiating C2C12 myoblasts. Together, these results suggest that Myog enhances the expression of MyoD-initiated late muscle genes through MyoD-dependent ability of Myog to induce chromatin remodeling, in which Myog-Brd4 interaction may be involved.

Molecular characterization of chemosensory protein genes in Bactrocera minax (Diptera: Tephritidae)

Wang Zhao‐Xiang,Qi Zhen‐hua,Chen Jian,Wang Fu‐Lian,Gui Lian‐You,Zhang Guo‐Hui 한국곤충학회 2021 Entomological Research Vol.51 No.7

Chemoreception is of great importance for survival of insects. Chemosensory proteins (CSPs) are believed to be involved in the perireceptor events of chemosensory system in many insect species, but this has not been clarified in the citrus fruit fly, Bactrocera minax, a serious dipteran pest of citrus crops. Previous studies indicated that four CSP genes were identified in many fly speices in Diptera. In the present study, we also identified four CSP genes in B. minax,namely BminCSP1–4, from a transcriptome database. All CSP proteins encoded by these genes bear the typical hallmarks of the CSP family: an N-terminal signal peptide and the four highly conserved cysteine residues. Phylogenetic analysis comparing with other dipteran CSPs indicated that dipteran CSPs may evolved from three ancestral CSP genes, and revealed the sequence diversities of BminCSPs and showed that BminCSP1–4 are clustered in separate groups, indicating the possibility of their contrasting function in B. minax. Furthermore, the tissue distribution of the four CSP genes in adult B. minax was analyzed by real-time quantitiative PCR. The results demonstrated that BminCSP3 are significantly transcriptionally enriched in antennae; BminCSP4 expressed primarily in heads; BminCSP1 and BminCSP2 showed high expressions in different tissues, such as antennae, abdomens and wings. Based on these findings, the different implications for the functions of BminCSPs are discussed. This study will offer a significant indication for further functional studies of the CSPs in B. minax

Design and Analysis of an Active Balancing Mechanism for a Vertical Axis Washing Machine

Hai-Wei Chen,Xun-Ting Yuan,Zhen Sun,Qiu-Qi Mou,Ming Xiong,Wei-Hua Wang 한국정밀공학회 2022 International Journal of Precision Engineering and Vol.23 No.7

In recent years, active balancing of washing machines has drawn much attention from manufactures. This paper proposes a novel active balancing mechanism for vibration suppression of a vertical axis washing machine which employs water for counteracting the unbalanced laundry. At first, a novel structure with two balancing planes sharing only one set of nozzles for injecting water is designed and the balancing capability of the structure is analyzed. Then, a dynamic model of the active balancing system is constructed. Vibration characteristics of the system including changes of the vibration amplitude and phase angle under different influences are studied. After that, a strategy for identifying the imbalance is proposed and an active control method is designed. At last, a washing machine armed with the active mechanism is manufactured. Both a fixed eccentric block and a pile of randomly distributed laundry are used to test the balancing effect. The results show that lateral vibrations of the washer can be greatly reduced by the active mechanism. Due to the simplicity of the structure and the satisfactory balancing effect, the mechanism proposed has a big potential to be employed in future washing machines.