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21.
Jong-Jin Pak Yong-Soo Jeong Soon-Jae Tae Dong-Sik Kim Yun-Yong Lee 《Metallurgical and Materials Transactions B》2005,36(4):489-493
The equilibrium solubility of titanium and nitrogen in Fe-Ni melts was measured in the presence of pure solid TiN under various
nitrogen pressures in the temperature range of 1843 to 1923 K. The activity coefficients of titanium and nitrogen relative
to a 1 mass pct standard state in liquid iron were calculated from the experimental results for Fe-Ni alloys of nickel contents
up to 30 mass pct. Nickel decreases the activity coefficient of titanium, but it increases the activity coefficient of nitrogen
in an Fe-Ni-Ti-N melt. Therefore, the effect of nickel on the solubility product of TiN is not significant. The first- and
second-order interaction parameters of nickel on titanium (e
Ti
Ni
and r
Ti
Ni
, respectively) were determined to be −0.0115 and 0 at 1873 K, respectively. Similarly, the interaction parameters of nickel
on nitrogen (e
N
Ni
and r
N
Ni
, respectively) were determined to be 0.012 and 0, respectively, at 1873 K. The temperature dependence of these interaction
parameters was also determined. 相似文献
22.
B. C. Pak B. S. Cho B. J. Baek C. S. Kim B. G. Min 《Journal of Mechanical Science and Technology》1993,7(3):223-230
Hydrodynamic comparison of two polymer valves with two mechanical valves is presented. The valves were perfused in a steady
flow system, and comparisons between the valves were made on the transvalvular pressure distribution and drop, opening area,
and leakage volume. Particular emphasis was placed on a slit-type bileaflet polymer valve which was newly designed and fabricated
in our research group. The results showed that the functional characteristics of a slit-type bileaflet polymer valve compared
favorably with that of mechanical valves. This valve may be a viable and inexpensive alternative, especially for short-term
use in TAH or VAD systems. 相似文献
23.
The thermophysical properties of thin platinum and nickel wires are investigated within the temperature range from room temperature
up to near to the melting point. We have measured the coefficient of heat exchange with the ambient media, the absorption
efficiency factor within the visible range, and the time constant of the bolometer cooling down. The data obtained are approximated
by analytical expressions. 相似文献
24.
Pak Chanil An Kwangil Jang Paeksan Kim Jonggun Kim Sok 《Multimedia Tools and Applications》2019,78(9):12027-12042
Multimedia Tools and Applications - This paper introduces new simple and effective improved one-dimension(1D) Logistic map and Sine map made by the output sequences of two same existing 1D chaotic... 相似文献
25.
26.
Min Jiang Xin-Hua Wang Jong-Jin Pak 《Metallurgical and Materials Transactions B》2014,45(4):1248-1259
ZrO2 crucible experiments were carried out in the laboratory to study the formation of low-melting-point inclusions in steel, during which aluminum deoxidization and a high-basicity calcium aluminate refining slag (CaO/SiO2: 6 to 8, Al2O3 40 to 45 pct) were used. Four experiments were done with different slag/steel reaction times (30, 60, 90, and 180 minutes). It was found that inclusions were mainly composed of CaO-Al2O3-ZrO2 with very limited SiO2, in spherical morphology and with sizes mainly less than 5 μm. They can be classified into two types according to the ZrO2 content. The first type contained much lower ZrO2, whereas a much higher level of ZrO2 was detected in the other type. An evolution of inclusions with the reaction time was observed and studied. The obtained results indicated that chemical compositions of inclusions were widely scattered in the CaO-Al2O3-ZrO2 phase diagram after 30 min reaction. However, the composition of inclusions became much more uniform and concentrated in low-melting-temperature regions at 60, 90, and 180 minutes, which would be favorable to prevent nozzle clogging and fatigue problems. Compared with the authors’ previous results obtained in MgO crucible experiments, it was found that low-melting-temperature inclusions can be targeted in shorter time in ZrO2 crucible experiments, without any degradation of cleanliness. 相似文献
27.
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29.
A Surface Tailoring Method of Ultrathin Polymer Gate Dielectrics for Organic Transistors: Improved Device Performance and the Thermal Stability Thereof
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Hyejeong Seong Jieung Baek Kwanyong Pak Sung Gap Im 《Advanced functional materials》2015,25(28):4462-4469
Tailoring the surface of the dielectric layer is of critical importance to form a good interface with the following channel layer for organic thin film transistors (OTFTs). Here, a simple surface treatment method is applied onto an ultrathin (<15 nm) organosilicon‐based dielectric layer via the initiated chemical vapor deposition (iCVD) to make it compatible with organic semiconductors without degrading its insulating property. A molecular‐thin oxide capping layer is formed on a 15 nm thick poly(1,3,5‐trimetyl‐1,3,5‐trivinyl cyclotrisiloxane) (pV3D3) by a brief oxygen plasma treatment. The capping layer greatly enhances the thermal stability of the dielectrics, without degrading the original mechanical flexibility and insulating performance of the dielectrics. Moreover, the surface silanol functionalities formed by the plasma treatment can also be utilized for the surface modification with silane compounds. The surface‐modified dielectrics are applied to fabricate low‐voltage operating (<5 V) pentacene‐based OTFTs. The highest field‐effect mobility of the device with the surface‐treated 15 nm thick pV3D3 is 0.59 cm2 V?1 s?1, which is improved up to two times compared to the TFT with the pristine pV3D3. It is believed that the simple surface treatment method can widely extend the applicability of the highly robust, ultrathin, and flexible pV3D3 gate dielectrics to design the surface of the dielectrics to match well various kinds of organic semiconductors. 相似文献
30.
Jayeeta Chattopadhyay Tara Sankar Pathak Daewon Pak Rohit Srivastava 《Korean Journal of Chemical Engineering》2016,33(5):1514-1529
Metal micro-/nano hollow spheres have been widely applied in numerous fields during the last decade. This review will only focus on the synthetic strategies to synthesize hollow spherical structures in the enhancement of their electrocatalytic activity, especially the metal hollow spherical materials. We present a comprehensive overview of synthetic strategies for metal hollow spherical structures which have been approached specifically in electrochemical reactions. These synthetic methods are mainly categorized as hard templates, soft templates, sacrificial templates and without templates. The review further includes electrocatalytic approaches of hollow spherical metals in different electrochemical processes, especially the methanol electro-oxidation reaction for methanol fuel cell application and hydrogen and oxygen evolution reactions in water electrolyzer, as metal hollow spherical materials are especially applied in these specific reactions. 相似文献