• Design & Manufacturing
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• v.17 no.2
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• pp.22-26
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• 2023

As Light-Emitting Diodes(LEDs) continue to advance in performance, their application in automotive lamps is increasing. Automotive LEDs utilize light guides not only for aesthetics but also to control light quantity and direction. Light guides employ patterns of a few hundred micrometers(㎛) to regulate the light, and the surface roughness(Ra) of these patterns can reach tens of nanometers(nm). Given that these light guides are produced through injection molding, mold processing technology with high surface quality micro-patterns is required. This study serves as a preliminary investigation into the development of high surface quality micro-pattern processing technology. It examines the surface roughness of the workpiece based on the cutting direction of the pattern and the cutting fluid type when cutting micro-patterns on STAVAX steel using cubic Boron Nitride(cBN) tools. The experiments involved machining a step-shaped micro-pattern with a height of 60 ㎛ and a pitch of 400 ㎛ in a 22×22 mm area under identical cutting conditions, with only the cutting direction and cutting fluid type being varied. The machining results of four cases were compared, encompassing two cases of cutting direction(parallel to the pattern, orthogonal to the pattern) and two cases of cutting fluid type (flood, mist). Consequently, the Ra value was found to be the highest(Ra 128.33 nm) when machining with the flood type in parallel to the pattern, while it was the lowest(Ra 95.22 nm) when machining with the mist type orthogonal to the pattern. These findings confirm that there is a difference of up to 25.8 % in the Ra value depending on the cutting direction and cutting fluid type.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.3
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• pp.75-85
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• 2009

This work proposes a 13b 100MS/s 0.13um CMOS ADC for 3G communication systems such as two-carrier W-CDMA applications simultaneously requiring high resolution, low power, and small size at high speed. The proposed ADC employs a four-step pipeline architecture to optimize power consumption and chip area at the target resolution and sampling rate. Area-efficient high-speed high-resolution gate-bootstrapping circuits are implemented at the sampling switches of the input SHA to maintain signal linearity over the Nyquist rate even at a 1.0V supply operation. The cascode compensation technique on a low-impedance path implemented in the two-stage amplifiers of the SHA and MDAC simultaneously achieves the required operation speed and phase margin with more reduced power consumption than the Miller compensation technique. Low-glitch dynamic latches in sub-ranging flash ADCs reduce kickback-noise referred to the differential input stage of the comparator by isolating the input stage from output nodes to improve system accuracy. The proposed low-noise current and voltage references based on triple negative T.C. circuits are employed on chip with optional off-chip reference voltages. The prototype ADC in a 0.13um 1P8M CMOS technology demonstrates the measured DNL and INL within 0.70LSB and 1.79LSB, respectively. The ADC shows a maximum SNDR of 64.5dB and a maximum SFDR of 78.0dB at 100MS/s, respectively. The ABC with an active die area of $1.22mm^2$ consumes 42.0mW at 100MS/s and a 1.2V supply, corresponding to a FOM of 0.31pJ/conv-step.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.47 no.8
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• pp.56-63
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• 2010

This work proposes a 12b 100MS/s 0.13um CMOS pipeline ADC for battery-powered mobile video applications such as DVB-Handheld (DVB-H), DVB-Terrestrial (DVB-T), Satellite DMB (SDMB), and Terrestrial DMB (TDMB) requiring high resolution, low power, and small size at high speed. The proposed ADC employs a three-step pipeline architecture to optimize power consumption and chip area at the target resolution and sampling rate. A single shared and switched op-amp for two MDACs removes a memory effect and a switching time delay, resulting in a fast signal settling. A two-step reference selection scheme for the last-stage 6b FLASH ADC reduces power consumption and chip area by 50%. The prototype ADC in a 0.13um 1P7M CMOS technology demonstrates a measured DNL and INL within 0.40LSB and 1.79LSB, respectively. The ADC shows a maximum SNDR of 60.0dB and a maximum SFDR of 72.4dB at 100MS/s, respectively. The ADC with an active die area of 0.92 $mm^2$ consumes 24mW at 1.0V and 100MS/s. The FOM, power/($f_s{\times}2^{ENOB}$), of 0.29pJ/conv. is the lowest of ever reported 12b 100MS/s ADCs.

• JSTS:Journal of Semiconductor Technology and Science
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• v.16 no.1
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• pp.70-79
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• 2016

This paper proposes a low-power range-scaled 14b 30 MS/s pipeline-SAR composite ADC for high-performance CIS applications. The SAR ADC is employed in the first stage to alleviate a sampling-time mismatch as observed in the conventional SHA-free architecture. A range-scaling technique processes a wide input range of 3.0VP-P without thick-gate-oxide transistors under a 1.8 V supply voltage. The first- and second-stage MDACs share a single amplifier to reduce power consumption and chip area. Moreover, two separate reference voltage drivers for the first-stage SAR ADC and the remaining pipeline stages reduce a reference voltage disturbance caused by the high-speed switching noise from the SAR ADC. The measured DNL and INL of the prototype ADC in a $0.18{\mu}m$ CMOS are within 0.88 LSB and 3.28 LSB, respectively. The ADC shows a maximum SNDR of 65.4 dB and SFDR of 78.9 dB at 30 MS/s, respectively. The ADC with an active die area of $1.43mm^2$ consumes 20.5 mW at a 1.8 V supply voltage and 30 MS/s, which corresponds to a figure-of-merit (FOM) of 0.45 pJ/conversion-step.

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.4
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• pp.320-324
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• 2016

A new eccentric forging process for camber bolts has been suggested in this study. The camber bolt is manufactured by a two-step process: the typical forging process for normal bolts and the trimming process for the eccentric flange. The processes are performed under high forging load and generate a large amount of chip during trimming. A new forging process has been required in order to overcome these problems. The eccentric forging is the new process in which the load axis is offset from the central axis, as against central load applied in a typical forging process. The eccentric forging process could reduce forging load and save the amount of chip. In order to manufacture camber bolts by an optimum process, it is required to adjust the geometry of eccentric die and the offset from the central axis.

• Korean Journal of Computational Design and Engineering
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• v.13 no.2
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• pp.139-152
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• 2008

In order to survive worldwide competition, today's industries are experiencing strong pressure to introduce higher quality products with lower cost and shorter lead-time. Therefore, the role of design in the process of product development is increasing in significance. In this research, two methods for improving the design capability are proposed: construction of design environment and design automation using 3D CAD system. The designers and design process are the core of product design using 3D CAD system. In order to maximize the design performance, construction of the design environment including selection of a suitable system, designer training for best use of the system, establishment of an efficient design process, and stabilization of the environment are required. A method is suggested to construct design environment by systematizing the contents of the projects and consulting experiences carried out for various categories of business such as electronic devices, motorcycles, electricity parts, sanitary wares, injection molds, and die casing molds. Design automation helps reduce tedious and time-consuming jobs, simplify complicated and error-prone modeling and drawing works to shorten the lead time and improve the product quality. To develop a design automation system, understanding the process and the related knowledge on design are very important before implementing the system using API provided by 3D CAD system. In this research, an eight-step procedure is proposed for the development of a design automation system. These eight steps are analysis of needs, determination of specification, verification of specification using 3D CAD system, inspection of related API functions, programming, field test, application in practice, and maintenance. A case study in which five design automation systems in the design of turbine generators using the proposed method is introduced in detail. These systems play important roles in the generation of various output items including 3D models, drafts, material information, and NC data. The case study shows how effectively the design time is reduced and the quality improved using those systems.

• JSTS:Journal of Semiconductor Technology and Science
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• v.11 no.2
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• pp.95-103
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• 2011

This paper proposes a 6b 1.2 GS/s 47.8 mW 0.17 $mm^2$ 65 nm CMOS ADC for high-rate wireless personal area network systems. The proposed ADC employs a source follower-free flash architecture with a wide input range of 1.0 $V_{p-p}$ at a 1.2 V supply voltage to minimize power consumption and high comparator offset effects in a nanometer CMOS technology. The track-and-hold circuits without source followers, the differential difference amplifiers with active loads in pre-amps, and the output averaging layout scheme properly handle a wide-range input signal with low distortion. The interpolation scheme halves the required number of pre-amps while three-stage cascaded latches implement a skew-free GS/s operation. The two-step bubble correction logic removes a maximum of three consecutive bubble code errors. The prototype ADC in a 65 nm CMOS demonstrates a measured DNL and INL within 0.77 LSB and 0.98 LSB, respectively. The ADC shows a maximum SNDR of 33.2 dB and a maximum SFDR of 44.7 dB at 1.2 GS/s. The ADC with an active die area of 0.17 $mm^2$ consumes 47.8 mW at 1.2 V and 1.2 GS/s.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.6
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• pp.330-335
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• 2017

The demand for electric motor fuel cells has surged in the automotive industry, leading to a recent increase in the demand for square aluminum cans used as fuel cell battery casings. The air vent located on the bottom of the rectangular battery casing prevents large explosions by intermittent pressure release prior to the accumulation of abnormally high pressures. Conventionally, the square cup battery casing is produced via six-step deep drawing, with the outer shape of the vent being manufactured by welding to the square battery casing. On the other hand, this study directly incorporated the air vent outlet into the bottom surface of the rectangular casing. The product of a coupled finite element analysis technique applying the thickness and contour generated from the square cup multi-step deep drawing formation analysis was used as the forging input shape. The results yielded increased prediction accuracy and the advanced prediction of defects, such as swelling and fracture. Based on the results of the initial analyses, two of the generated forging shapes were determined to be suitable, with the optimal forging shape being determined by molding analysis. The results presented here were validated by mold fabrication and a subsequent comparison of the actual and analytical results.

• Journal of Korean Philosophical Society
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• v.147
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• pp.215-237
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• 2018

The purpose of this study is to illuminate the precise nature and the central line of Kant's proof of the causal principle stated in the Second Analogy of the 2nd. edition of the Critique of Pure Reason. The study argues for the following thesis: 1. The proof of the Second Analogy concerns only the causal principle called the "every-event-some-cause" principle, and not the causal law(s) called the "same-cause-same-event" principle. 2. The goal of the proof is to establish the possibility of knowledge of an temporal order of successive states of an object. 3. The proof is broadly an single transcendental argument in two steps. The 1st. step is an analytic argument that infers from the given perceptions of an oder of successive states of an objects to the conclusion that the causal principle is the necessary condition for the objectivity of dies perceived order. The 2nd. step is a synthetic argument that infers from the formal nature of time to the conclusion that the causal principle is a necessary condition for die possibility of objective alterations and of empirical knowledge of these alterations. 4. The poof involves not the 'non sequitur' assumed by P. F. Strawson, that is, Kant infers not directly from a feature of our perceptions to a conclusion regarding the causal relations of distinct states of affairs that supposedly correspond to these perceptions.

• Journal of Korean Medical classics
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• v.13 no.2 s.17
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• pp.174-188
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• 2000

The meaning of Tiangui(天癸) in $Suwen{\cdot}Shanggutianzhenlun\;素問{\cdot}上古天眞論$ is very important because it has the cause of 'having a child' and it shows the signs to being healthy. But until now there have been many arguments about what the correct meaning of Tiangui is. The most important thing in these arguments is to compare and analyze Neijing(內經) commentators' views, and to understand differences between their views. So I compared and analyzed by focusing on Neijing(內經) text, the other books with explanatory notes, and other commentators' views, and, after that. I got the following results. 1. On the meaning of Tian(天), Wangbing(王氷) and Mashi(馬蒔) considered that it is inborn. Zhangjiecong(張志聽) considered it as the Yang(陽) producing Yin(陰) Zhangjiebin(張介賓) regarded it as the Yang(陽) of Gua symbol. On the meaning of the Gui(癸). Zhangjiebin(張介賓) said that it is Yin qi(陰氣) which is the prior step to Xing(形). Mashi(馬蒔) and Zhangzhicong(張志聽) said that it is spirit or Jingxue(spiritual sanguine) which is the concrete constituents in our body. 2. On the relation bet ween Tian(天) and Gui(癸), Mashi(馬蒔) and Zhangzhicong(張志聽) said that Gui(癸) is made from Tian(天), and Zhangjiebin(張介賓) said that Tian is intrinsic in Gui(癸). 3. On the relation between Tiangui(天癸) and Jingxue(精血), Yangshangshan(楊上善). Wangbing(王氷), and Zhangjiebin(張介賓) regarded Tiangui(天癸) as a concrete matter which is the prior step to becoming Jingxue(精血). Mashi(馬蒔) and Zhangjiecong(張志聽) considered Tiangui(天癸) as a concrete matter. Mashi(馬蒔) considered Tiangui(天癸) as Jing(精)which is directly related to pregnancy. Zhangjiecong(張志聽) regarded Tiangui(天癸) as Jingxue(精血) which controls general physiology of men and women. 4. On the function of Tiangui(天癸), Yangshangshan(楊上善) and Wangbing(王氷) considered that Tiangui (天癸) has relation to menstruation. pregnancy. and, production and extinction of Jing(精). Zhangjiecong(張志聽) argued that Tiangui(天癸) strengthens and warms muscle and derma. and controls differential physiology between men and women, and said that the maintenance of its activity is based on the acquired spirit of food. A book of 『Huangti Neijing Yanjiu Dacheng(黃帝內經硏究大成)』 said that the function of Tiangui(天癸) is to promote generation, to develop the second sexual symbol, and to make growing and aging in body. It also said that Tiangui(天癸) has some relation to kidney and other organs, Chong Meridian, Ren Meridian, Du Meridian, and Dai Meridian. 5. Other commentators of 『Neijing(內經)』 accepted the meaning of Tiangui(天癸) as the prior step of both man's spiritual overflowing and woman's menstruation. 6. On the relation between Tiangui(天癸). and, Cheng and Ren Meridians, Yangshangshan(楊上善) and Zhangjiecong(張志聽) said that Tiangui(天癸) has direct relation with two meridians. Wangbing(王氷) said that Tiangui(天癸) and two meridians have no direct relation. Now I compared commentaors' views of Tiangui(天癸) and studied the differences between their views. I concluded that on the concept of Tiangui(天癸), Zhangjiebin(張介賓)'s explanations express well its connotative meaning. And on the function of Tiangui (天癸), Zhangjiecong(張志聽)'s explanations are excellent because he organized well his seniors' views, and extended its meaning by showing Neijing(內經)'s phrases related to Chong and Ren Meridians. Also, Mashi(馬蒔) suggested that if Tiangui(天癸) comes earlier than normal. people will die soon. But I think that more studies on male and female bodies are needed as to Mashi(馬蒔)'s argument.