Wear-life analysis of deep groove ball bearings based on Archard wear theory

Guangwei Yu,Wei Xia,Zhuoyuan Song,Rui Wu,Siling Wang,Yuan Yao 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.7

A quasi-dynamic method is proposed to evaluate the characteristics of ball bearings, which include pressure distribution over the contact area between the ball and the raceway, sliding velocity distribution, and lubrication parameters. The extent of permissible wear is confirmed based on the Archard wear equation. A mathematical model for wear-life analysis is then presented for 6000 deep groove ball bearings with axial loads. The effects of axial loads, rotating speed, and structural parameters on wear characteristics of bearings are analyzed. A number of conclusions are drawn. Based on the proposed mathematical model, the wear life of a bearing decreases with increased axial load. The wear life of the bearing decreases as the rotational speed of the inner ring increases. The wear life of the bearing exhibits nearly linear increment as the groove curvature of the inner ring increases and decreases as the groove curvature of the outer ring increases.

Distinct growth phenomenon observed on L-Arg․ CF3COOH crystals

Xiaojing Liu,Zeyan Wang,Guanghui Zhang,Guangwei Yu,Aidong Duan,Xinqiang Wang,Dong Xu 한국물리학회 2009 Current Applied Physics Vol.9 No.1

Atomic force microscopy has been employed to study the growth behaviour on the {101} facets of L-Arg ․ CF3COOH crystals grown at 25℃ at a supersaturation of σ = 0.2. Nucleation on the wider step terraces and a large nucleus composed of two separate 2D nuclei were observed for the first time. For the region where blocking occurs convex pattern are found in the macrosteps, which correspond to the sites of the impurities that act as pinning points hindering step propagation. Finally, liquid inclusions will be generated because of disparate formation mechanisms. Atomic force microscopy has been employed to study the growth behaviour on the {101} facets of L-Arg ․ CF3COOH crystals grown at 25℃ at a supersaturation of σ = 0.2. Nucleation on the wider step terraces and a large nucleus composed of two separate 2D nuclei were observed for the first time. For the region where blocking occurs convex pattern are found in the macrosteps, which correspond to the sites of the impurities that act as pinning points hindering step propagation. Finally, liquid inclusions will be generated because of disparate formation mechanisms.

Injectable In situ Forming Chitosan-Based Hydrogels For Curcumin Delivery

Titima Songkroh,Xiaojun Ma,Hongguo Xie,Weiting Yu,Xiudong Liu,Guangwei Sun,Xiaoxi Xu 한국고분자학회 2015 Macromolecular Research Vol.23 No.1

In this paper, a series of injectable in situ forming chitosan-based hydrogels were prepared by chemicalcrosslinking of chitosan and genipin with the cooperation of ionic bonds between chitosan and sodium salts at roomtemperature. Four hydrogels (A, B, C, and D) were obtained by mixing chitosan, genipin and a sodium salt of trisodiumphosphate (Na3PO4·12H2O), sodium sulfate (Na2SO4), sodium sulfite (Na2SO3), or sodium bicarbonate (NaHCO3)and examined for their characteristics, morphology, and rheological properties. Their cell viability assaysexhibited low toxicity and the localized in situ gel formation was detected after subcutaneous injections in rat. Curcuminwhich possesses many pharmaceutical potentials but has low bioavailability, was chosen as a drug model. Invitro curcumin release profiles exhibit sustained release properties with initial burst release for all hydrogels withabout 3 to 6 times higher cumulative release than other gel controls. The results of this study demonstrate that ourhydrogels have a potential as local curcumin carriers.

Full-space Cloud of Random Points with a Scrambling Metasurface

Li, Zile,Dai, Qi,Mehmood, Muhammad Q.,Hu, Guangwei,yanchuk, Boris Luk’,Tao, Jin,Hao, Chenglong,Kim, Inki,Jeong, Heonyeong,Zheng, Guoxing,Yu, Shaohua,Alù,, Andrea,Rho, Junsuk,Qiu, Cheng-Wei Nature Publishing Group UK 2018 Light, science & applications Vol.7 No.1

<▼1><P>With the rapid progress in computer science, including artificial intelligence, big data and cloud computing, full-space spot generation can be pivotal to many practical applications, such as facial recognition, motion detection, augmented reality, etc. These opportunities may be achieved by using diffractive optical elements (DOEs) or light detection and ranging (LIDAR). However, DOEs suffer from intrinsic limitations, such as demanding depth-controlled fabrication techniques, large thicknesses (more than the wavelength), Lambertian operation only in half space, etc. LIDAR nevertheless relies on complex and bulky scanning systems, which hinders the miniaturization of the spot generator. Here, inspired by a Lambertian scatterer, we report a Hermitian-conjugate metasurface scrambling the incident light to a cloud of random points in full space with compressed information density, functioning in both transmission and reflection spaces. Over 4044 random spots are experimentally observed in the entire space, covering angles at nearly 90°. Our scrambling metasurface is made of amorphous silicon with a uniform subwavelength height, a nearly continuous phase coverage, a lightweight, flexible design, and low-heat dissipation. Thus, it may be mass produced by and integrated into existing semiconductor foundry designs. Our work opens important directions for emerging 3D recognition sensors, such as motion sensing, facial recognition, and other applications.</P></▼1><▼2><P><B>Metasurfaces: scrambling light for 3D detection and recognition</B></P><P>Firing light at a manufactured 'metasurface'—one carrying patterns at a smaller scale than the wavelength of the light—fills large volumes of space with defined points of light, potentially improving 3-D recognition and sensor applications. Cheng-Wei Qui and colleagues at the National University of Singapore, with co-workers across Asia and in the USA, created their unique metasurface from amorphous silicon. Light is scattered from and transmitted through the material to generate a cloud of data points in the surrounding space in which the structure and motion of objects under study can be analyzed. The initial development work with this “scrambling metasurface” suggests it could improve pattern recognition, including face recognition, motion detection and augmented reality applications. The researchers describe how their innovation overcomes significant limitations of existing methods in these fields.</P></▼2>

Beyond Canonical PROTAC: Biological targeted protein degradation (bioTPD)

Huifang Wang,Runhua Zhou,Fushan Xu,Kongjun Yang,Liuhai Zheng,Pan Zhao,Guangwei Shi,Lingyun Dai,Chengchao Xu,Le Yu,Zhijie Li,Jianhong Wang,Jigang Wang 한국생체재료학회 2023 생체재료학회지 Vol.27 No.00

Targeted protein degradation (TPD) is an emerging therapeutic strategy with the potential to modulate disease associated proteins that have previously been considered undruggable, by employing the host destructionmachinery. The exploration and discovery of cellular degradation pathways, including but not limited toproteasomes and lysosome pathways as well as their degraders, is an area of active research. Since the conceptof proteolysis-targeting chimeras (PROTACs) was introduced in 2001, the paradigm of TPD has been greatlyexpanded and moved from academia to industry for clinical translation, with small-molecule TPD being particularlyrepresented. As an indispensable part of TPD, biological TPD (bioTPD) technologies including peptide-, fusionprotein-, antibody-, nucleic acid-based bioTPD and others have also emerged and undergone significantadvancement in recent years, demonstrating unique and promising activities beyond those of conventional small molecule TPD. In this review, we provide an overview of recent advances in bioTPD technologies, summarize theircompositional features and potential applications, and briefly discuss their drawbacks. Moreover, we present somestrategies to improve the delivery efficacy of bioTPD, addressing their challenges in further clinical development.