Application of the sheet electrode to enhance the geometric characteristics of micro-holes fabricated by electrochemical discharge machining

Zhongning Guo,Shunzhi Qiao,Liangliang Wang,Kai Zhang,Yingjie Xiao,Zhixiang Zou 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.11

The electrochemical discharge machining (ECDM) is an advanced machining technology used to fabricate micro-holes in glass. In this study, a sheet tool electrode is employed to increase electrolyte circulation in machining zone. The effect of pulse voltage, frequency, duty cycle, electrolyte concentration, and tool rotation speed on the geometric properties of micro-holes were evaluated. The results showed that when using a sheet tool electrode, the machining depth increased by 42.9 %, and the machining efficiency increased by 51.1 %, while the entrance diameter was reduced by 13.9 % than cylindrical tool electrode. Additionally, the heat-affected zone (HAZ) and entrance hole surface quality is improved. On the other hand, the Taguchi method was employed to analyze the relative importance of the machining parameters on geometric characteristics of micro-holes (i.e. drilled depth and entrance diameter of micro-holes). Finally, the entrance hole overcut of 148 μm was successfully fabricated with a depth of 2520 μm. It was discovered that using a sheet tool electrode is a simple method for machining a deep micro-hole with high machining efficiency and a range entrance hole diameter overcut that is acceptable.

A Novel Safe File Sharing Method Based on Cloud Storage Structure in DHT Networks

Zhongning Lu,Gaofeng Shen 보안공학연구지원센터 2015 International Journal of Security and Its Applicat Vol.9 No.7

Safe file sharing mechanism in cloud storage is one of the most significant elements that affects the development of security technology. With application of homomorphic key agreement mechanism、Shamir secret sharing algorithm. Bloom Filter and B-tree search algorithm and Rsync data updating algorithm, a safe file sharing scheme in cloud storage is established based on cloud storage infrastructure of DHT networks. Under the circumstance of cloud storage, the scheme can make full use of the sharing mechanism and achieve the confidentiality and integrity of the file. Based on DHT networks, the analysis and test of data sharing are conducted in the paper. Together with file upload and download, the test of data encryption and decryption is done on the basis of Dropbox. As the result shows, the scheme puts forward a safe and effective solution to safe file sharing in cloud storage.

Improvement of Channel Eé ciency in Mobile Communications by User Relay Scheme

Zhongning JIA,Kouichi MUTSUURA,Osamu AKIZUKI,YoonTze CHIN,Shiro HANDA,Shinjiro OSHITA 대한전자공학회 2002 ITC-CSCC :International Technical Conference on Ci Vol.2002 No.7

Improving the Machining Quality of Micro Structures by Using Electrophoresis-Assisted Ultrasonic Micromilling Machining

Junfeng He,Zhongning Guo,Haishan Lian,Junjie Wang,Xiaolei Chen,Jiangwen Liu 한국정밀공학회 2020 International Journal of Precision Engineering and Vol.7 No.1

Traditional micromilling leaves burrs and has a high surface roughness in the workpiece, which compromises the microstructural machining quality. Electrophoresis-assisted ultrasonic micromilling machining (EUMM) is proposed to solve this problem. An electrophoresis assisted electric field is applied to attract abrasive particles into the machining gap. Combined with the ultrasonic vibrations of the workpiece, the impact and grinding effect of these abrasive particles in the machining gap removes burrs that are generated during machining and reduces the surface roughness of the microstructure. Micro channels were generated for this study to verify the proposed method. The experimental results show that the EUMM significantly reduces burr formation during microchannel milling. The EUMM also decreases the surface roughness (Ra); the bottom roughness using the EUMM (0.33 µm) is lower than that with either the ultrasonic micromilling (UMM) or traditional micromilling. The EUMM also improves the sidewall roughness since the grinding and particle impacts significantly smooth the sidewalls. The particles during EUMM ensure a low surface roughness of 0.34 µm for the vertical sidewalls. Furthermore, the EUMM has a lesser effect on the width of the micro channels; as the spindle speed increases, the microchannel width only increases from 486 to 498 µm.

Experimental study on fabrication of large-scale micro cylinders array by mask jet electrochemical deposition

Ting Huang,Zhongning Guo,Guiming Liang,Shunzhi Qiao,Pengcheng Cai,Zhixiang Zou 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.8

The mask jet electrochemical deposition was used to deposit the large-scale micro cylinders array in this study. The effect of the pulse peak current density, pulse frequency, pulse duty cycle, injection pressure and scanning speed on the deposition characteristics (i.e. deposition height, surface roughness and surface quality of micro cylinders) have been investigated. The experiment results showed that the mean height and the surface roughness of micro cylinders increased form the peak current density. Moreover, due to a high pulse frequency provided a shorter pulse on-time, and significantly facilitating the renewal of the ion concentration in the electroforming fluid. A higher pulse frequency and larger duty cycle provide a better deposition characteristic. The injection pressure was found to have a significant effect on the height, the surface roughness and surface appearance of micro cylinders. Furthermore, when using higher scanning speed, the crystalline particles of the cast layer decrease, significantly decreasing the surface roughness. Based on discussed, the pulse current density of 12 A/dm 2 , a pulse frequency of 3000 Hz, a pulse duty cycle of 30 %, a jet inlet pressure of 80 kPa, a scanning speed of 8 mm/s and a number of scans of 100 is optimal parameters. Finally, by using these parameters, a large-area micro cylindrical array structures with a height of 22.53±2.46 μm and diameter of 205±3.21 μm were successfully fabricated. It can be concluded that the mask jet electrochemical deposition is a simple method to realize the electrodeposition of large-area array structures.

Investigation on pulse electrochemical machining by coated electrode

Wu Ming,Zhongning Guo,Yongjun Tang,Guan Wang,Taotao Sun,Shuzhen Jiang 한국생산제조학회 2014 한국생산제조시스템학회 학술발표대회 논문집 Vol.2014 No.9(2)

Practical Vitamin D Supplementation Using Machine Learning

Tyler Fugere,Zhongning Jim Chen,Issam Makhoul 대한골대사학회 2020 대한골대사학회지 Vol.27 No.2

Background: Patients with breast cancer are at increased risk of developing osteoporosis. Maintaining normal levels of vitamin D may decrease the risk of osteoporosis, and vitamin D levels must be corrected in patients who develop osteoporosis before beginning bone modifying agents. Therefore, it is important to correct insufficient vitamin D levels in a timely manner. In clinical practice, current guidelines for replacement regimens often fail to rapidly correct vitamin D levels. The goal of this study was to review data in order to predict what replacement regimen(s) were most effective at repleting vitamin D levels. Methods: For this retrospective cohort study, data was collected from medical records of 2,164 female patients with breast cancer with Institutional Review Board approval. Total level change per week was the primary outcome and was compared for the most commonly used vitamin D replacement regimens adjusted for age, race, body mass index, creatinine clearance, endocrine therapy, and initial level. Results: Higher weekly doses of vitamin D supplementation had a more significant impact on the rate of correction compared to lower daily doses. Generalized linear model was used to develop an online calculator that predicts time to vitamin D level correction adjusted for significant patient characteristics for 5 common replacement regimens as well as no intervention. Conclusions: When choosing a vitamin D replacement regimen for patients with vitamin D deficiency, we recommend clinicians use the online calculator to ensure that the chosen regimen will enable the patient to reach vitamin D sufficiency in a timely manner.

Developments and applications of jet electrochemical machining

Wu Ming,Zhongning Guo,Taotao Sun 한국생산제조학회 2014 한국생산제조시스템학회 학술발표대회 논문집 Vol.2014 No.9(2)

IODINE REMOVAL EFFICIENCY IN NON-SUBMERGED AND SUBMERGED SELF-PRIMING VENTURI SCRUBBER

Ali, Majid,Yan, Changqi,Sun, Zhongning,Gu, Haifeng,Wang, Junlong,Khurram, Mehboob Korean Nuclear Society 2013 Nuclear Engineering and Technology Vol.45 No.2

The objective of this conducted research is to study the iodine removal efficiency in a self-priming venturi scrubber for submerged and non-submerged operating conditions experimentally and theoretically. The alkaline solution is used as an absorbent, which is prepared by dissolving sodium hydroxide (NaOH) and sodium thiosulphate ($Na2S_2O_3$) in water to remove the gaseous iodine ($I_2$) from the gas. Iodine removal efficiency is examined at various gas flow rates and inlet concentrations of iodine for submerged and non-submerged operating conditions. In the non-submerged venturi scrubber, only the droplets take part in iodine removal efficiency. However, in a submerged venturi scrubber condition, the iodine gas is absorbed from gas to droplets inside the venturi scrubber and from bubbles to surrounding liquid at the outlet of a venturi scrubber. Experimentally, it is observed that the iodine removal efficiency is greater in the submerged venturi scrubber as compare to a non-submerged venturi scrubber condition. The highest iodine removal efficiency of $0.99{\pm}0.001$ has been achieved in a submerged self-priming venturi scrubber condition. A mathematical correlation is used to predict the theoretical iodine removal efficiency in submerged and non-submerged conditions, and it is compared against the experimental results. The Wilkinson et al. correlation is used to predict the bubble diameter theoretically whereas the Nukiyama and Tanasawa correlation is used for droplet diameter. The mass transfer coefficient for the gas phase is calculated from the Steinberger and Treybal correlation. The calculated results for a submerged venturi scrubber agree well with experimental results but underpredicts in the case of the non-submerged venturi scrubber.

Synthesis of hairpin DNA mediated Au-Ag bimetallic nanomushrooms for antibacterial application

Fu, Jingtai,Huang, Lu,Yu, Zhongning,Zhang, Zhuomin,Li, Gongke Techno-Press 2021 Advances in nano research Vol.11 No.1

Precise control of the synthesis of bimetallic nanoparticles with specific morphology and structure is of great significance due to their excellent catalytic, optical and biological property. DNA molecules are considered as a kind of efficient templates to mediate the precise synthesis of bimetallic nanoparticles with homogeneous morphology due to their specific and controllable structure. In this study specific hairpin DNA strands were successfully utilized as templates to mediate the synthesis of special mushroom-like Au-Ag bimetallic nanoparticles with a high yield of > 90%. Several key factors greatly influencing the precise control of the morphology and UV-Vis characteristics of the proposed Au-Ag nanomushrooms during synthesis were investigated and optimized in detail, including the structure of template DNA, loading amounts of DNA, types of reductant agents and surfactants. Then, the formation mechanism of hairpin DNA mediated Au-Ag nanomushrooms was studied. Finally, the proposed Au-Ag nanomushrooms with good biocompatibility were applied for the antibacterial study by the growth curve of E. coli. The proposed Au-Ag nanomushrooms showed the effective inhibition capability for the growth of E. coli. The results suggested that these DNA mediated Au-Ag nanomushrooms possessed great potential applications for biomedical science in future.