• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.24 no.11
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• pp.792-798
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• 2012

A general concept on the definition of the second law efficiencies of thermodynamic cycles is introduced. The efficiency is defined to be proportional to the entropy generation divided by the maximum possible entropy generation. This way of definition of the cycle efficiency is clear and concise and, moreover, follows faithfully the concept of the second law of thermodynamics. This definition is applied to heat engine, refrigerator and heat pump. The second law efficiencies of heat engine and refrigeration cycles are derived, which are the same as the existing ones, respectively. The second law efficiency of heat pump, however, finds to be different from the existing one. Discussion is given about the difference and its cause.

• The Korean Journal of Ceramics
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• v.6 no.3
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• pp.206-208
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• 2000

0.65 mol% MgO-doped LiNbO$_3$single crystals were grown by CZ method. The obtained single crystals were colorless and transparent. Noncritically phase-matched second harmonic generation (SHG) of 532-nm radiation from 1064-nm in MgO-doped LiNbO$_3$has been investigated by using pulsed Nd:YAG laser. The phase-matching temperature was room temperature. SHG conversion efficiencies were typically achieved higher than 50% at the phase-matching temperature with no photorefractive damage in the region of fundamental power density which was used in this experiment. The thermo-birefringence coefficient and the electro-birefringence coefficient of SHG were calculated from the temperature phase-matching profile with the electric field.

• Progress in Superconductivity and Cryogenics
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• v.21 no.4
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• pp.53-58
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• 2019

The critical current is one of the key parameters of high temperature superconducting (HTS) racetrack coils. Therefore, it is significant to calculate critical currents of HTS coils. This paper introduces a fast iterative algorithm for calculating the critical current of second generation (2G) HTS coils. This model does not need to solve long charging transients which greatly reduced the amount of calculation. To validate this model, the V-I curve of four 2G HTS double racetrack coils are measured. The effect of the silicon steel sheet on the critical current of the racetrack coil is also studied based on this algorithm.

• Korean Journal of Optics and Photonics
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• v.10 no.4
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• pp.301-305
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• 1999

The phase matching conditions of the new optical crystal grown by Czochralski pulling method, YCOB($YCa_4O(BO_3)_3$) with wavelength were suggested, and the second harmonic generation efficiency for the fundamental of Nd:YAG laser of 1064 nm was investigated. The variation of nonlinearity with rare earth ion doping was also investigated by measuring the second harmonic generation efficiencies of $Yb^{3+}$ + $Nd^{3+}$and ion doped YCOBs.

• The Journal of Natural Sciences
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• v.12 no.1
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• pp.31-39
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• 2002

Second harmonic generation was measured in porous silicon superlattices surface which were made by changing and anodization current density and the anodization time periodically in the process of obtaining porous silicon. The technique of second harmonic generation is used as a probe to the surface of porous silicon superlattice by using Nd:YAG laser. We have investigated the surface structure and nonlinear-optics properties of porous silicon superlattice.

• Asia pacific journal of information systems
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• v.33 no.4
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• pp.899-933
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• 2023

The second-generation mobile instant messaging (SMIM) proliferates with various relationship management functions: group chats, audio/video chats, file sharing, real-time location sharing, and nonverbal graphics, such as emojis and stickers. This study integrates the important but often overlooked affordances theory into innovation diffusion and proposes an SMIM continuance intention model. SMIM is a social affordance platform for users to develop new friendships and maintain their relationships. Integrated diffusion of innovation and affordance theoretical frameworks, this study investigates the influence of four factors on the success of using SMIM apps to improve friendship development and relationship management. Data were collected from 231 participants using a survey questionnaire in a public university in Taiwan. The findings confirm the effects of friendship development and relationship maintenance on the intention of users to continue using SMIM apps. Implications for research and practice are discussed.

• The Research Journal of the Costume Culture
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• v.8 no.5
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• pp.707-716
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• 2000

The purpose of this study was to explane the Net generation's characters appearing in the apparel brand naming for them. For this study, first I was trying to explane the New generation characters, second 45 apparel brands were selected by market research and questionaire survey was conducted on 53 the Net generation collage women of age 20 thru 21. Third, the apparel brands were classified into four types according to the characters reflecting in the apparel brand naming : First, the apparel brand type using the figures such as STORM=292513, 1492Miles. Second, the apparel brand type that two or more words are abbreviated into one word. Third, the apparel brand type containing more than one meaning in a brand naming or spelling the words as it pronunciate. Fourth, the apparel brand type using of slang. In conclusion, These types of the apparel brands were related to characters of the New generation, i.e., they who have grown in the advance of digital civilization are skilled in the communication through computer, internet and mobile phone, so that they are familiar with the figures, combined words, or abbreviated words etc. Also, they have individual, sensitivity character and seek after individuality, current fashion. They have also a tendency to accept various the sense of value, while they have a refusing tendency a custom or convention which the older generation has conformited.

• Journal of the Korea Furniture Society
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• v.24 no.1
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• pp.1-14
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• 2013

Since the 1980s the development of American art furniture was embodied its concept by second-generation furniture artists affected and educated from the first generation that has implanted art furniture fundamental values. Besides, embracing inevitably needs of the new era going with the social change rather than dwell on the nature of mere handicraft era, it has evolved with economic revival in the United States, the attention and increased consumption of the public, and ongoing government-sponsored. And more recently, the American contemporary Art Furniture faces another change in the non-boundary phenomena between art and design. American art furniture since the 1980s are summarized as three major trends: Art furniture embellished with traditional hand-craft, Art furniture featured the individualistic avant-guard characteristic, Art furniture eroded the distinction between art and design. By analyzing focusing on the furniture artists and their works in contemporary art furniture deployment aspects since the 1980s, the purpose of this study can be utilized as a method to measure the forward direction, internationally competitive, creativity, and artistic value of the domestic art furniture.

• Journal of the Korean Solar Energy Society
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• v.31 no.6
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• pp.49-56
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• 2011

In this study a novel cogeneration system driven by low-temperature sources at a temperature level below $190^{\circ}C$ is investigated by first and second laws of thermodynamics. The system consists of Organic Rankine Cycle(ORC) and an additional heat generation as a parallel circuit. Seven working fluids of R143a, R22, R134a, R152a, $iC_4H_{10}$(isobutane), $C_4H_{10}$(butane), and R123a are considered in this work. Maximum mass flow rate of a working fluid relative to that of the source fluid and optimum turbine inlet pressure are considered to extract maximum power from the source. Results show that due to a combined heat and power generation, both the efficiencies by first and second laws can be significantly increased in comparison to a power generation, however, the second law efficiency is more resonable in the investigation of cogeneration systems. Results also show that the working fluid for the maximum system efficiency depends on the source temperature.

• International Journal of Precision Engineering and Manufacturing
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• v.8 no.2
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• pp.20-25
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• 2007

This paper describes a second-generation dual sine-grid surface encoder for 2-D position measurements. The surface encoder consisted of a 2-D grid with a 2-D sinusoidal pattern on its surface, and a 2-D angle sensor that detected the 2-D profile of the surface grid The 2-D angle sensor design of previously developed first-generation surface encoders was based on geometric optics. To improve the resolution of the surface encoder, we fabricated a 2-D sine-grid with a pitch of $10{\mu}m$. We also established a new optical model for the second-generation surface encoder that utilizes diffraction and interference to generate its measured values. The 2-D sine-grid was fabricated on a workpiece by an ultra precision lathe with the assistance of a fast tool servo. We then performed a UV-casting process to imprint the sine-grid on a transparent plastic film and constructed an experimental setup to realize the second-generation surface encoder. We conducted tests that demonstrated the feasibility of the proposed surface encoder model.