Effect of Deep Cryogenic Treatment on Machinability and Wear Mechanism of TiAlN Coated Tools during Dry Turning

Hui-Bo He,Wen-Qiang Han,Hua-Ying Li,Dong-Yang Li,Jun Yang,Tao Gu,Tao Deng 한국정밀공학회 2014 International Journal of Precision Engineering and Vol. No.

TiAlN coatings were deposited on the YT15 tungsten carbide inserts by magnetron sputtering technique. The TiAlN coated tools weredeep cryogenic treatment (DCT) at -196oC for 30 h. The dry turning tests of 40Cr steel were carried out to evaluate performancesof uncoated, no cryogenically treated (NCT) and DCT coated tools on the CA6140A lathe. The effect of the three kinds of tools oncutting forces, cutting temperature, surface qualities and tool wear had been investigated to assess the performance of DCT coatedtools. Results of the investigation showed that the cutting forces and cutting temperature obtained by DCT coated tools weresignificantly decreased in comparison with the uncoated and NCT coated tools, especially at higher cutting speeds. Flank wear ofthe DCT coated inserts was less than that of the NCT coated inserts under the same cutting conditions. The DCT coated insertsproduced a good surface finish and yield a tool life of about 65 min. The wear mechanisms of the DCT coated carbide tools are mainlyabrasive and adhesive wear, accompanied with diffusion and oxidation wear.

Effect of $MoS_2$-Based Composite Coatings on Tribological Behavior and Efficiency of Gear

He, Hui-Bo,Li, Hua-Ying,Xu, Zhe-Zhu,Kim, Dong-Uk,Lyu, Sung-Ki 한국정밀공학회 2010 International Journal of Precision Engineering and Vol.11 No.6

$MoS_2$-based Ti composite coatings were deposited on the SCM420 alloy and gears using an RF magnetron sputtering (RFMS) system. While $MoS_2$ coating had been coated on the silicon substrate. The coatings structures were compared to each other to find the effect of Ti. The composite coatings have been tested in a ball-on-disk tribometer to investigate tribological behavior at various conditions. The scratch test was conducted to characterize adhesion force between composite coatings and substrates. The structure of the coatings has been extensively studied by a variety of techniques, including optical microscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM), etc. The composite coatings were also applied to the gears of a reduction gearbox. The efficiency of uncoated and $MoS_2$-based Ti coated gear was measured and compared at various input rotating speed under absorption oil film condition. It was found that the efficiency of gear had significantly improved after $MoS_2$-based Ti composite coatings deposition.

Research on the Cutting Performances and Wear Mechanisms of TiAlCrN Coated Tools during Dry Turning

Hui-Bo He,Hua-Ying Li,Xian-Ying Zhang,Qi-Bin Yue,Jun Zhang,Lu Ma,Yuan-ming Li 한국정밀공학회 2019 International Journal of Precision Engineering and Vol.20 No.2

Physical vapour deposition technique was used to deposit TiAlCrN coatings on the YT15 tungsten carbide inserts. The dry turning tests of 20CrMo steel were carried out to evaluate performances of TiAlCrN coated and uncoated tools on the CA6140A lathe. The effect of the two kinds of tools on cutting forces, cutting temperature, surface roughness and tool wear had been investigated to assess the performance of TiAlCrN coated tools. The results showed that the cutting force and cutting temperature obtained by TiAlCrN coated tools were decreased and the TiACrN coated tools produced a better surface finish in comparison with the uncoated tools. The TiAlCrN coated tools yield working life about 45 min, which was two times of that for uncoated tools. The wear mechanisms of the TiAlCrN coated tools were mainly oxidation and boundary wear, accompanied with diffusion wear.

Effect of MoS2-Based Composite Coatings on Tribological Behavior and Efficiency of Gear

Hui-Bo He,Hua-Ying Li,Zhe-Zhu Xu,Donguk Kim,류성기 한국정밀공학회 2010 International Journal of Precision Engineering and Vol. No.

MoS2-based Ti composite coatings were deposited on the SCM420 alloy and gears using an RF magnetron sputtering (RFMS) system. While MoS2 coating had been coated on the silicon substrate. The coatings structures were compared to each other to find the effect of Ti. The composite coatings have been tested in a ball-on-disk tribometer to investigate tribological behavior at various conditions. The scratch test was conducted to characterize adhesion force between composite coatings and substrates. The structure of the coatings has been extensively studied by a variety of techniques, including optical microscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM), etc. The composite coatings were also applied to the gears of a reduction gearbox. The efficiency of uncoated and MoS2-based Ti coated gear was measured and compared at various input rotating speed under absorption oil film condition. It was found that the efficiency of gear had significantly improved after MoS2-based Ti composite coatings deposition.

Optimal Design of a Tilling Machine Reduction Gearbox Using Matlab

Hui-Bo He,Hua-Ying Li,Sung-Ki Lyu,Sung-Hoon Tak,Sung-Min Moon,Qi Zhang 한국정밀공학회 2009 International Journal of Precision Engineering and Vol.10 No.2

This paper describes the optimal design of the reduction gearbox of a tillage machine. The minimum center diameter was selected as the objective, and the contact fatigue strength. bending fatigue strength, condition of nonintervention, and oil film thickness ratio of the gearbox were applied as constraint conditions. The optimal model was solved by a Matlab program. The results show that the center diameter of the reduction gearbox decreased by about 10%. The resulting decrease in weight and volume led to a reduction in the amount of gearbox matelial and a consequent decrease in production cost.

A Study on Major Factors Influencing Dry Cutting Temperature of AISI 304 Stainless Steel

Hui-Bo He,Hua-Ying Li,Jun Yang,Xian-Yin Zhang,Qi-Bin Yue,Xue Jiang,류성기 한국정밀공학회 2017 International Journal of Precision Engineering and Vol.18 No.10

TiN coated and uncoated tools were used to conduct the dry cutting temperatures for AISI 304 stainless steel. Effects of cutting variables on cutting temperatures were investigated using single factor experiment method. The optimal cutting parameters of cutting temperatures were obtained through orthogonal experiment method. The forming process and temperature distribution of chips were analyzed using finite element method (FEM). The results show that cutting temperature generally increases with the increase of cutting speed and feed rate. When depth of cut increases at the range of 0.8-1.5 mm, the cutting temperature increases firstly and decreases subsequently. And the cutting temperature of TiN coated tool is lower than that of uncoated tool. The optimal parameters of cutting temperature are obtained by orthogonal experiment, which is A1B1C3. The highest temperature appears on the second deformation zone by the simulation.

Reliability Evaluation Technique for Electrical Distribution Networks Considering Planned Outages

Bo Hu,Xiao-Hui He,Kan Cao 대한전기학회 2014 Journal of Electrical Engineering & Technology Vol.9 No.5

The reliability evaluation of the electrical distribution networks (EDN) requires sufficient consideration of the effects of planned outages. The planned outages of the EDN can be divided, by outage models and their effects on the reliability into two major categories: by equipment and by feeder. After studying the characteristics of different categories of planned outages, this paper expands the classification of load points by outage time from 4 types to 7 types and defines corresponding reliability parameters for the different types. By using the section algorithm, this paper proposes a reliability evaluation technique of EDN considering equipment random failures and two categories of planned outages. The proposed technique has been applied to the RBTS-BUS6 test system and some practical EDNs in China. The study results demonstrate that the proposed technique is of higher practical value and can be used for evaluating the reliability performance of EDN more efficiently considering the planned outages.

Changing patterns of Serum CEA and CA199 for Evaluating the Response to First-line Chemotherapy in Patients with Advanced Gastric Adenocarcinoma

He, Bo,Zhang, Hui-Qing,Xiong, Shu-Ping,Lu, Shan,Wan, Yi-Ye,Song, Rong-Feng Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.8

Background: This study was designed to investigate the value of CEA and CA199 in predicting the treatment response to palliative chemotherapy for advanced gastric cancer. Materials and Methods: We studied 189 patients with advanced gastric cancer who received first-line chemotherapy, measured the serum CEA and CA199 levels, used RECIST1.1 as the gold standard and analyzed the value of CEA and CA199 levels changes in predicting the treatment efficacy of chemotherapy. Results: Among the 189 patients, 80 and 94 cases had increases of baseline CEA (${\geq}5ng/ml$) and CA199 levels (${\geq}27U/ml$), respectively. After two cycles of chemotherapy, 42.9% patients showed partial remission, 33.3% stable disease, and 23.8% progressive disease. The area under the ROC curve (AUC) for CEA and CA199 reduction in predicting effective chemotherapy were 0.828 (95%CI 0.740-0.916) and 0.897 (95%CI 0.832-0.961). The AUCs for CEA and CA199 increase in predicting progression after chemotherapy were 0.923 (95%CI 0.865-0.980) and 0.896 (95%CI 0.834-0.959), respectively. Patients who exhibited a CEA decline ${\geq}24%$ and a CA199 decline ${\geq}29%$ had significantly longer PFS (log rank p=0.001, p<0.001). With the exception of patients who presented with abnormal levels after chemotherapy, changes of CEA and CA199 levels had limited value for evaluating the chemotherapy efficacy in patients with normal baseline tumor markers. Conclusions: Changes in serum CEA and CA199 levels can accurately predict the efficacy of first-line chemotherapy in advanced gastric cancer. Patients with levels decreasing beyond the optimal critical values after chemotherapy have longer PFS.

Stochastic Channel Modeling for Railway Tunnel Scenarios at 25 GHz

Danping He,Bo Ai,Ke Guan,Zhangdui Zhong,Bing Hui,김준형,HeeSangChung,김일규 한국전자통신연구원 2018 ETRI Journal Vol.40 No.1

More people prefer using rail traffic for travel or for commuting owing to its convenience and flexibility. The railway scenario has become an important communication scenario in the fifth generation era. The communication system should be designed to support high-data-rate demands with seamless connectivity at a high mobility. In this paper, the channel characteristics are studied and modeled for the railway tunnel scenario with straight and curved route shapes. On the basis of measurements using the “Mobile Hotspot Network” system, a three-dimensional ray tracer (RT) is calibrated and validated for the target scenarios. More channel characteristics are explored via RT simulations at 25.25 GHz with a 500-MHz bandwidth. The key channel parameters are extracted, provided, and incorporated into a 3rd-Generation-Partnership-Project-like stochastic channel generator. The necessary channel information can be practically realized, which can support the link-level and system-level design of the communication system in similar scenarios.

A Discovery of Low Hydraulic Resistance Channel Along Meridians

Wei-Bo Zhang,Yu-Ying Tian,Hong Li,Jia-He Tian,Ming-Fu Luo,Fa-Liang Xu,Guang-Jun Wang,Tao Huang,Yi-Hui Xu,Rui-Hong Wang 사단법인약침학회 2008 Journal of Acupuncture & Meridian Studies Vol.1 No.1

A hydro-mechanic model was put forward to study the fundamental nature of acupuncture meridians. The basic state of low hydraulic resistance was tested on humans and mini pigs using three methods. The first, a modified Guyton’s method, proved that there was lower hydraulic resistance on meridians compared with nonmeridians. The second scanning method involved a single pressure transducer that can find the lowest resistance point in tissue, and the third method used two transducers and provided a more stable measurement. Using the latter method, low hydraulic resistance points were found very close to low impedance points along meridians. The transmission of artificial interstitial fluid pressure waves was measured to examine their connection to the low resistance points, with the result that a good connection between the points was confirmed. This means the points form channels along the meridians that we refer to as low hydraulic resistance channels. The channel was imaged through isotopic tracing and a migration of isotope 99mTe could be found along the channel. The layer of the channel was detected by injecting Alcian blue and the track was found beneath the skin. All of the above experiments suggest the existence of a new type of channel in living tissues that has not yet been described in modern science, but coincides quite well with the Qi channel theory of traditional Chinese medicine. A hydro-mechanic model was put forward to study the fundamental nature of acupuncture meridians. The basic state of low hydraulic resistance was tested on humans and mini pigs using three methods. The first, a modified Guyton’s method, proved that there was lower hydraulic resistance on meridians compared with nonmeridians. The second scanning method involved a single pressure transducer that can find the lowest resistance point in tissue, and the third method used two transducers and provided a more stable measurement. Using the latter method, low hydraulic resistance points were found very close to low impedance points along meridians. The transmission of artificial interstitial fluid pressure waves was measured to examine their connection to the low resistance points, with the result that a good connection between the points was confirmed. This means the points form channels along the meridians that we refer to as low hydraulic resistance channels. The channel was imaged through isotopic tracing and a migration of isotope 99mTe could be found along the channel. The layer of the channel was detected by injecting Alcian blue and the track was found beneath the skin. All of the above experiments suggest the existence of a new type of channel in living tissues that has not yet been described in modern science, but coincides quite well with the Qi channel theory of traditional Chinese medicine.