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101.
Young?Tae?Im Seung?Tae?ChoiEmail author Tae?Sang?Park Jae?Hyun?Kim 《Journal of Mechanical Science and Technology》2004,18(1):12-19
Using LSM (laser scanning method), the radius of curvature due to thermal deformation in polyimide film coated on Si substrate
is measured. Since the polyimide film shows viscoelastic behavior, i.e., the modulus and deformation of the film vary with
time and temperature, we estimate the relaxation modulus and the residual stresses of the polyimide film by measuring the
radius of curvature and subsequently by performing viscoelastic analysis. The residual stresses relax by an amount of 10%
at 100°C and 20% at 150°C for two hours. 相似文献
102.
Recent primary concern for the design of high performance heat exchanger and highly integrated electronic equipments is to develop an active and creative technologies which enhance the heat transfer without obstructing the coolant flows. In this study, we found through the LDV measurement that the gaseous cavitation induced by ultrasonic vibration applied to the CO2 saturated water in the square cross-sectioned straight duct flow enhances the turbulence much more than the case of non-ultrasonic or normal ultrasonic conditions without gaseous cavitation does. We also found that gaseous cavitation can enhance effectively the turbulent heat transfer between the heating surfaces and coolants by destructing the viscous sublayer. 相似文献
103.
This paper reports a technique for measuring the velocity and dissolved oxygen concentration (DOC) fields simultaneously in a micro-scale water flow using oxygen-sensitive particles (OSP) and a conventional microparticle image velocimetry method. The OSP were fabricated using a dispersion polymerization method by synthesizing platinum (II) octaethyporphyrin (PtOEP) with polystyrene, and used as tracer particles and oxygen sensors. An ultraviolet light-emitting diode with a wavelength of 385 nm was used as the excitation light source, and phosphorescence images of OSP were captured on a CMOS high-speed camera. The interrogation window concept was used to measure the DOC in water from the dispersed phosphorescence intensity distribution of OSP. The Stern–Volmer equations in the interrogation windows were obtained from in situ calibration. Water containing OSP with DOC values of 0 and 100 % were injected into a Y-shaped microchannel using a double loading syringe pump. The velocity and DOC field over the entire channel area were quantified. 相似文献
104.
105.
Seung Youb Han Sang Yong Shin Hyuk-Joong Lee Byeong-Joo Lee Sunghak Lee Nack J. Kim Jai-Hyun Kwak 《Metallurgical and Materials Transactions A》2012,43(3):843-853
An investigation was conducted into the effects of annealing temperature on microstructure and tensile properties of ferritic
lightweight steels. Two steels were fabricated by varying the C content, and were annealed at 573 K to 1173 K (300 °C to 900 °C)
for 1 hour. According to the microstructural analysis results, κ-carbides were formed at about 973 K (700 °C), which was confirmed by equilibrium phase diagrams calculated from a THERMO-CALC
program. In the steel containing low carbon content, needle-shaped κ-carbides were homogeneously dispersed in the ferrite matrix, whereas bulky band-shaped martensites were distributed in the
steel containing high carbon content. In the 973 K (700 °C)-annealed specimen of the steel containing high carbon content,
deformation bands were formed throughout the specimen, while fine carbides were sufficiently deformed inside the deformation
bands, thereby resulting in the greatest level of strength and ductility. These results indicated that the appropriate annealing
treatment of steel containing high carbon content was useful for the improvement of both strength and ductility over steel
containing low carbon content. 相似文献
106.
Hur JH Kim KM Chang M Lee SR Lee D Lee CB Lee MJ Kim YB Kim CJ Chung UI 《Nanotechnology》2012,23(22):225702
We report a physical model for multilevel switching in oxide-based bipolar resistive memory (ReRAM). To confirm the validity of the model, we conduct experiments with tantalum-oxide-based ReRAM of which multi-resistance levels are obtained by reset voltage modifications. It is also noticeable that, in addition to multilevel switching capability, the ReRAM exhibits extremely different switching timescales, i.e. of the order of 10(-7)?s to 10(0)?s, with regard to reset voltages of only a few volts difference which can be well explained by our model. It is demonstrated that with this simple model, multilevel switching behavior in oxide bipolar ReRAM can be described not only qualitatively but also quantitatively. 相似文献
107.
Seung Hee Ha Jong-Ho Hwang Do Hyung Kim Min-Dae Kim Cheol-Woong Choi Young-Il Jeong Chung Wook Chung Cy Hyun Kim Dae Hwan Kang 《Materials Research Bulletin》2012,47(10):2735-2738
The aim of this study was to prepare sunitinib-loaded biodegradable films using poly(l-lactide-co-?-caprolactone) (PLCL) for anti-tumor drug delivery. Sunitinib-loaded PLCL film has a rough surface, while empty film has a smooth surface. PLCL film loaded with 5% (w/w) sunitinib showed an absence of a crystalline peak of sunitinib, while sharp peaks were observed at 10% (w/w) loading, indicating that sunitinib was molecularly distributed in the polymer matrix at 5% (w/w). A drug release study revealed an initial burst during the first 2 h, followed by continuous release until 24 h. Since weight loss of film was <10% for 1 week, drug release mechanism was dominantly dependent on the diffusion-mediated release of drugs to the medium. Sunitinib has a dose-dependent anti-proliferation effect against HuCC-T1 human cholangiocarcinoma cells in vitro. These results indicate that sunitinib-loaded PLCL film is a appropriate candidate as a vehicle for anti-tumor drug delivery. 相似文献
108.
Investigating the effect of touch-key size on usability of In-Vehicle Information Systems (IVISs) is one of the most important research issues since it is closely related to safety issues besides its usability. This study investigated the effects of the touch-key size of IVISs with respect to safety issues (the standard deviation of lane position, the speed variation, the total glance time, the mean glance time, the mean time between glances, and the mean number of glances) and the usability of IVISs (the task completion time, error rate, subjective preference, and NASA-TLX) through a driving simulation. A total of 30 drivers participated in the task of entering 5-digit numbers with various touch-key sizes while performing simulated driving. The size of the touch-key was 7.5 mm, 12.5 mm, 17.5 mm, 22.5 mm and 27.5 mm, and the speed of driving was set to 0 km/h (stationary state), 50 km/h and 100 km/h. As a result, both the driving safety and the usability of the IVISs increased as the touch-key size increased up to a certain size (17.5 mm in this study), at which they reached asymptotes. We performed Fitts' law analysis of our data, and this revealed that the data from the dual task experiment did not follow Fitts' law. 相似文献
109.
110.
Chang Min Shin Seung Han Kang Byung Chai Lee 《Journal of Mechanical Science and Technology》2012,26(4):1107-1114
In this paper, the performance of a 4-node tetrahedral element with rotational DOFs is improved using strain smoothing techniques.
A partition-of-unity based approximation is used to construct the tetrahedral element with rotational DOFs. To overcome the
stiff behavior of the tetrahedral element with rotational DOFs, a face-based strain smoothing technique is used. The stiffness
matrix is expressed explicitly and the element performance is evaluated through numerical examples, which demonstrate that
the proposed strain smoothed tetrahedral elements with rotational DOFs satisfy the patch test and have a better performance
than other tetrahedral elements with rotational DOFs. 相似文献