• 한국분말야금학회:학술대회논문집
• /
• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
• /
• pp.132-133
• /
• 2006

Optimized choice of material for two principally different types of PM components is presented. The first is characterized by high stresses in areas with high stress concentrations (for example synchronizer hubs with very sharp notches, typically <0.25mm in the pre-synchronizer slot and the inner splines). The second type has slightly larger notch radii (small spur gears and sprockets with typically notch radii between 1- 3mm). Diffusion alloyed materials are well suited for sharp notch components. Pre-alloyed materials are also well suited for applications with sharp notches if compressive residual stresses in the notch roots are created by appropriate process control. A free choice of material is available for components with the larger notch radii.

• 대한추나의학회지
• /
• 제1권1호
• /
• pp.83-90
• /
• 2000

Oryeong-San, Pangpungtongseong-San, Rangkyeoksanwha-Tang, Sipeemikwanjoong -Tang and Taeumjoui-Tang are not only examined using the code which are related to overweight in the QRIS but are also investigated the level of Free Radical using the Free Radical Measurement after steeping those 5 prescriptions in water. The results are as follows: 1. We indicated in the study of QRIS that 5 kinds of medicines which used most frequently In the treatment of the obesity appeared to affect the Immune system, spleen, kidneys, pancreas, the fatigue toxicity, TSH, and the metabolic disability but did not influence high on the contents of overweight and those of fatty cell, as well. in addition, there were no significant differences between the prescriptions as regards testosterone and progesterone. 2. In the Free Radical Measurement, Rangkyeoksanwha-Tang evaluated significantly high level of Free Radical, whereas others appear to have the similar level of Free Radical. These findings suggest that the treatment of the obesity affects particular body parts with respect to the control of overweight, although those medicines are not related directly to the areas(such as fatty cell Code), it is possible that they influence on the cure for the obesity. Furthermore, they indicate that with soaking prescription, Free Radical is not produced as much as we expected.

• 한국재료학회지
• /
• 제19권6호
• /
• pp.337-343
• /
• 2009

In this study, we optimized Pb-free Sn/Ni plating thickness and conditions were optimized to counteract the environmental regulations, such as RoHS and ELV(End-of Life Vehicles). The $B_{10}$ life verification method was also suggested to have been successful when used with the accelerated life test(ALT) for assessing Pb-free solder joint life of piezoelectric (PZT) ceramic resonator. In order to evaluate the solder joint life, a modified Norris-Landzberg equation and a Coffin-Manson equation were utilized. Test vehicles that were composed of 2520 PZT ceramic resonator on FR-4 PCB with Sn-3.0Ag-0.5Cu for ALT were manufactured as well. Thermal shock test was conducted with 1,500 cycles from $(-40{\pm}2)^{\circ}C$ to $(120{\pm}2)^{\circ}C$, and 30 minutes dwell time at each temperature, respectively. It was discovered that the thermal shock test is a very useful method in introducing the CTE mismatch caused by thermo-mechanical stress at the solder joints. The resonance frequency of test components was measured and observed the microsection views were also observed to confirm the crack generation of the solder joints.

• 대한한방부인과학회지
• /
• 제29권2호
• /
• pp.83-98
• /
• 2016

Objectives: This Study was designed to investigate the effect of Oxygen chamber to recover muscle fatigue. Methods: Twenty Subjects were divided into Oxygen Chamber Group (n=10) and Rest group (n=10). Subjects visited hospital two times, blood tests were performed 3 times for each visit. 1st blood test was performed in 4 hours hunger state. 2nd blood test was performed within 5 minutes after the 6 minutes bike exercise. 3rd blood test was performed after the 40 minutes Oxygen treatment or 40 minutes rest in bed. Blood test items were Lactate, Glucose, Lactate Dehydrogenase, Creatine Kinase, Free Fatty Acid. 2nd visit was applied 1st visit process, But Oxygen Chamber group was crossed over to Rest Group, Rest Group was crossed over to Oxygen Chamber group. The Blood test result was analyzed with paired T-test using SPSS for Windows version 21. Results: The reduction of Lactate in Oxygen Chamber Group (6.86±2.07 mmol/ℓ) was higher than Rest group (6.57±2.33 mmol/ℓ), but it was not statically significant (p=0.68). The reduction of Glucose in Oxygen Chamber Group (6.85±12.14 mg/dl) was lower than Rest group (7.60±9.83 mg/dl), but it was not statically significant (p=0.83). The reduction of Lactate Dehydrogenase in Oxygen Chamber Group (16.10±14.91 mmol/ℓ) was lower than Rest group (19.75±12.46 mg/dl), but it was not statically significant (p=0.41). The reduction of Creatine Kinase in Oxygen Chamber Group (13.40±5.69 U/ℓ) was lower than Rest group (15.25±8.01 U/ℓ), but it was not statically significant (p=0.41). The reduction of Free Fatty Acid in Oxygen Chamber Group (285.50±174.13 uEq/ℓ) was higher than Rest group (196.15±131.58 uEq/ℓ), but it was not statically significant (p=0.07). Conclusions: This study showed Oxygen chamber therapy could be effective to recover muscle fatigue.

• 국제물리치료학회지
• /
• 제4권2호
• /
• pp.562-565
• /
• 2013

The fact that flip-flops, one of many different types of unstable shoes, are light and relatively easy to put on, accounts for their popularity among people. But because flip-flops rely heavily on the support of a single thong between your first and second toes, they impose a huge amount of pressure onto lower leg. Thus in the following experiment we tried to examine the different effects of flip-flops and running shoes in terms of their effect on muscle activity and fatigue of tibialis anterior and gastrocnemius during walking. In order to measure an electromyogram we used Free EMG system. 10 men and 10 women in running shoes ran on treadmills for 15 minutes at 4.8km/h, 2 days later the same experiment was carried out, but this time, in flip-flops. p value turned out to be greater than .05 and thus there was no considerable difference between the effects of flip-flops and running shoes on muscle activity and fatigue during walking. Therefore we conclude that despite the fact that flip-flops are considered unstable, their effects on muscle activity and fatigue of tibialis anterior and gastrocnemius are negligible.

• Smart Structures and Systems
• /
• 제26권2호
• /
• pp.227-239
• /
• 2020

Despite proven effectiveness and accuracy in laboratories, the existing damage assessment based on guided ultrasonic waves (GUWs) or acoustic emission (AE) confronts challenges when extended to real-world structural health monitoring (SHM) for railway tracks. Central to the concerns are the extremely complex signal appearance due to highly dispersive and multimodal wave features, restriction on transducer installations, and severe contaminations of ambient noise. It remains a critical yet unsolved problem along with recent attempts to implement SHM in bourgeoning high-speed railway (HSR). By leveraging authors' continued endeavours, an SHM framework, based on actively generated diffuse ultrasonic waves (DUWs) and a benchmark-free condition contrast algorithm, has been developed and deployed via an all-in-one SHM system. Miniaturized lead zirconate titanate (PZT) wafers are utilized to generate and acquire DUWs in long-range railway tracks. Fatigue cracks in the tracks show unique contact behaviours under different conditions of external loads and further disturb DUW propagation. By contrast DUW propagation traits, fatigue cracks in railway tracks can be characterised quantitatively and the holistic health status of the tracks can be evaluated in a real-time manner. Compared with GUW- or AE-based methods, the DUW-driven inspection philosophy exhibits immunity to ambient noise and measurement uncertainty, less dependence on baseline signals, use of significantly reduced number of transducers, and high robustness in atrocious engineering conditions. Conformance tests are performed on HSR tracks, in which the evolution of fatigue damage is monitored continuously and quantitatively, demonstrating effectiveness, adaptability, reliability and robustness of DUW-driven SHM towards HSR applications.

• 한방재활의학과학회지
• /
• 제30권2호
• /
• pp.37-46
• /
• 2020

Objectives In this study, we analyzed the effect of Dioscoreae Rhizoma on exercise practice ability and blood fatigue variable factor in the forced swimming test. Methods Male mice were divided into four group. Mice were administrated with saline, Discorae Rhizoma extracted by water (DRW), Discorae Rhizoma extracted by 30% ethanol (DRE), red ginseng (RG), orally once per day, for 1 week. Exercise performance was evaluated by exhaustive swimming time and weights. Glycogen contents of liver and soleus muscle were measured at the end of the experiment. In addition, the biochemical parameters such as asparate aminotransferase (AST), alanine aminotransferase (ALT), blood urea nitrogen, creatine, lactate dehydrogenase (LDH), ammonia, triglycerides (TG), total cholesterol (TC) and free fatty acid (FFA) were analyzed. Results Both DRW and DRE showed an improvement of swimming endurance compared with control group. Levels of ALT, ammonia, TG, TC and FFA were significantly decreased in both DRW and DRE compared with control group. Levels of AST, Creatine were significantly reduced in DRE group compared with control group. Moreover LDH showed only a tendency to increase in the DRW and DRE groups. Conclusions In summary, the present study showed that Dioscoreae Rhizoma improved in physical fatigue and exercise practice ability and DRE improved the superior than those of DRW.

• 혜화의학회지
• /
• 제21권2호
• /
• pp.149-156
• /
• 2013

1. Objectives This study is about a "Soyangin" hyperthyroidism patient with palpitation, facial flushing, fatigue, hand tremor and vertigo etc. In this case, we evaluated the effect of Oriental medicine treatment for hyperthyroidism. 2. Methods This patient was treated by Sasang constitutional herbal medication based on "Donguisusebowon". Acupuncture and west medications were used together. We evaluated the clinical progress through two method, Blood Test(T3, Free T4, TSH) and VAS(Visual Analogue Scale). 3. Results During 2months treatment, chief complaints, symptoms and blood test results(T3, Free T4, TSH) of this patient were improved. 4. Conclusion This study shows that Yangkyuksanhwa-tang is an effective treatment for "Soyangin" hyperthyroidism patient.

• Journal of Computational Design and Engineering
• /
• 제3권3호
• /
• pp.215-225
• /
• 2016

In recent years, the automotive industry has known a remarkable development in order to satisfy the customer requirements. In this paper, we will study one of the components of the automotive which is the twist beam. The study is focused on the multicriteria design of the automotive twist beam undergoing linear elastic deformation (Hooke's law). Indeed, for the design of this automotive part, there are some criteria to be considered as the rigidity (stiffness) and the resistance to fatigue. Those two criteria are known to be conflicting, therefore, our aim is to identify the Pareto front of this problem. To do this, we used a Normal Boundary Intersection (NBI) algorithm coupling with a radial basis function (RBF) metamodel in order to reduce the high calculation time needed for solving the multicriteria design problem. Otherwise, we used the free form deformation (FFD) technique for the generation of the 3D shapes of the automotive part studied during the optimization process.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2002년도 추계학술대회논문집
• /
• pp.68-73
• /
• 2002

It is necessary first to understand dynamic characteristics of bus full BIW assembly for fatigue endurance analysis. FE model has been used usually for analyzing the dynamic behavior of structures. A lot of experience and effort, however, is necessary to make the credible FE model. Experimental modal analysis of structures has been performed to verify the credibility of initial FE model and to update the model. In this work, experimental modal analysis was performed to understand dynamic characteristics of bus full BIW assembly in free-free boundary condition and the result was used to verify the initial FE model. In addition, some practical techniques, which were used in this experiment, were mentioned.