• ETRI Journal
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• 제18권3호
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• pp.171-179
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• 1996

Fully passivated low noise AlGaAs/InGaAs/GaAs pseudomorphic (PM) HEMT with wide head T-shaped gates were fabricated by dose split electron beam lithography (DSL). The dimensions of gate head and footprint were optimized by controlling the splitted pattern size, dose, and spaces of each pattern. We obtained stable T-shaped gate of $0.15{\mu}m$ gate length with $1.35{\mu}m-wide$ head. The maximum extrinsic transconductance was 560 mS/mm. The minimum noise figure measured at 18 GHz at $V_{ds}=2V andI_{ds}=17mA$ was 0.41 dB with associated gain of 8.19 dB. At 12 GHz, the minimum noise figure and an associated gain were 0.26 and 10.25 dB, respectively. These noise figures are the lowest values ever reported for GaAs-based HEMTs. These results are attributed to the extremely low gate resistance of wide head T-shaped gate having a ratio of the head to footprint dimensions larger than 9.

• Bulletin of the Korean Chemical Society
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• 제21권11호
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• pp.1119-1124
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• 2000

$\beta-Cyclodextrin$ derivatives connected with diaza-18-crown-6 through flexible bridges (R) at the secondary face 1a-c (1a: R = $-(CH_2)4-;$ 1b: R = $-CH_2CH_2OCH_2CH2-;$ 1c: R = $-(CH_2)8-)$ have been prepared. The associa tion constants of 1 with (2-naphthoxy)alkylammonium ions (2a: alkyl = butyl; 2b: alkyl = octyl) were determined by induced circular dichroism (ICD) spectroscopy and it was found that the derivatization of $\beta-CD$ with the diazacrown resulted in enhanced binding with 2, compared to the native $\beta-CD.$ ICD Characteristics of the host-guest complexes indicate that a part of the alkylammonium moiety of 2 is protruded from the secondary side of the $\beta-CD$ cavity, and the guest molecules 2a and 2b move to the secondary and primary side, respectively, to make the binding of the ammonium group with the diaza-18-crown-6 moiety more feasible. The energy accompanied by the relocation of the guest molecules inside $\beta-CD$ moiety is compensated by the interaction energy between the ammonium ion and diazacrown ether.

• Bulletin of the Korean Chemical Society
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• 제18권2호
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• pp.213-217
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• 1997

Magnesium reduction of Mo(N-C6H3-2,6-i-Pr2)2Cl2(DME) in the presence of trimethylphosphine led to a mixture of Mo(N-C6H3-2,6-i-Pr2)(PMe3)2Cl3, 1, and Mo2(PMe3)4Cl4, 2. In solution 1 is slowly air-oxidized to Mo(N-2,6-i-Pr2-C6H3)(OPMe3)(PMe3)Cl3, 3. 1 is chemically inert to carbon nucleophiles (ZnMe2, ZnEt2, AlMe3, AlEt3, LiCp, NaCp, TlCp, NaCp*, MeMgBr, EtMgBr), oxygen nucleophiles (LiOEt, LiO-i-Pr, LiOPh, LiOSPh), and hydrides (LiBEt3H, LiBEt3D). Crystal data for 1: orthorhombic space group P212121, a=11.312(3) Å, b=11.908(3) Å, c=19.381(6) Å, Z=4, R(wR2)=0.0463 (0.1067). Crystal data for 2: monoclinic space group Cc, a=18.384(3) Å, b=9.181(2) Å, c=19.118(3) Å, b=124.98(1)°, Z=4, R(wR2)=0.0228 (0.0568). Crystal data for 3: orthorhombic space group P212121, a=11.464(1) Å, b=14.081(2) Å, c=16.614(3) Å, Z=4, R(wR2)=0.0394 (0.0923).

• Journal of the korean society of oceanography
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• 제34권1호
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• pp.43-48
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• 1999

The latest-Quaternary paleoceanographic history of the Ulleung Basin, the East Sea (the Sea of Japan) is reconstructed on the base of planktonic foraminifera, oxygen and carbon isotopes, and accelerator mass spectrometer radiocarbon (AMS-$^{14}$C) data from two cores. Sinistral populations of Neogloboquadrina pachyderma are dominant during the last glacial period while dextral forms of Neogloboquadrina pachydeyma are abundant in the Holocene. An abrupt increase in ${\delta}^{18}$O values in both cores that began about 11 ka B.P may indicate the Younger Dryas cooling episode. A low-salinity event, marked by light ${\delta}^{18}$O values (0-1 %), is observed before the Younger Dryas event. As previous works suggested, the low-salinity event is probably due to the freshening of surface water caused by fresh water input from Huang Ho river and/or the excess of precipitation over evaporation. The lowest salinity water in the Ulleung Basin was probably continued from approximately 18 ka B.P. to 15 ka B.P. The ${\delta}^{18}$O values have gradually decreased since the Younger Dryas as a result of the continuous inflow of the warm Tsushima Current into the East Sea.

• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2008년도 정보통신설비 학술대회
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• pp.414-417
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• 2008

This paper presents the design and analysis of 2.45GHz Low-IF Mixer using CMOS 0.18um. The Mixer is implemented by using the Gilbert-type configuration, current bleeding technique, and the resonating technique for the tail capacitance. And the design of this Double Balance Mixer is based on its lineaity since it is important in the interference cancellation system. The low flicker noise mixer is implemented by incorporating a double balanced Gilber-type configuration, the RF leakage-less current bleeding technique, and Cp resonating technique. The proposed mixer has a simulated conversion gain of 16dB a simulated IIP3 of -3.3dBm and P1dB is -19dBm. A simulated noise figure of 6.9dB at l0MHz and a flicker corner frequency of 510kHz while consuming only 10.65mW od DC power. The layout of Mixer for one-chip design in a 0.18-um TSMC process has 0.474mm$\times$0.39 mm size.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• 제23권1호
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• pp.26-34
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• 2020

Purpose: To compare the clinical features, diagnostic findings, and medications of children with infrequent bowel movements or fecal soiling. Methods: This study enrolled 333 children (189 male; age range, 1 month to 18 years) diagnosed with functional constipation by Rome III or IV criteria. We classified them into 3 groups (infrequent bowel movement without fecal soiling [G3-a], infrequent bowel movement with fecal soiling [G3-b], and fecal soiling only [G3-c]) and into 2 subgroups of fecal soiling (G2-b) or not (G2-a). Retrospective data on clinical characteristics, colon transit time (CTT) test results, and medications were collected. The Wilcoxon rank-sum test, Kruskal-Wallis test, Chi-square test, and Fisher's exact test were used for the statistical analysis. Results: The median age (months) and interquartile range (IQR) was 33 (45) in G3-a, 54 (40) in G3-b, and 73 (48) in G3-c (p<0.0001). G3-c had the latest onset (median, 18; IQR, 18; p=0.0219) and longest symptom duration (24 [24], p=0.0148). PEG 4000 was used in 60.6% (G3-a), 96.8% (G3-b), and 83.2% (G3-c) of patients (p<0.0001). The median age (months) and IQR were 33.0 (45.0) in G2-a and 63.5 (52.5) in G2-b (p<0.0001). G2-b had later onset (median, 12; IQR, 19.5; p=0.0062) and longer symptom duration than G2-a (24 [12], p=0.0070). PEG 4000 was used in 60.6% (G2-a) and 88.3% (G2-b) of children (p<0.0001). No statistically significant intergroup differences were seen in maintenance laxative dose, CTT, or CTT type. Conclusion: Infrequent bowel movement and fecal soiling represent the advanced stage of chronic functional constipation.

• Asian Pacific Journal of Cancer Prevention
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• 제13권4호
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• pp.1365-1370
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• 2012

The high mobility group box-1 (HMGB1) protein and NALP3 inflammasome have been identified to play important roles in inflammation and cancer pathogenesis, but the relationships between the two and cancer remain unclear. The current study investigated the relationship between HMGB1 and the NALP3 inflammasome in THP-1 macrophages. HMGB1 was found unable to activate the NALP3 inflammasome and failed to induce the release of the IL-$1{\beta}$ and IL-18 in THP-1 macrophages. HMGB1 was also found significantly enhanced the activity of ATP to induce IL-$1{\beta}$ and IL-18 by the induction of increased expression of pro-IL-$1{\beta}$ and pro-IL-18. This process was dependent on activation of RAGE, MAPK p38 and NF-${\kappa}B$ signaling pathway. These results demonstrate that HMGB1 promotes the synthesis of pro-IL-$1{\beta}$ and pro-IL-18 in THP-1 macrophages by the activation of p38 MAPK and NF-${\kappa}B$ through RAGE. HMGB1 likely plays an important role in the first step of the release of the IL-$1{\beta}$ and IL-18, preparing for other cytokines to induce excessive release of IL-$1{\beta}$ and IL-18 which promote inflammation and cancer progression.

• 전자공학회논문지
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• 제53권7호
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• pp.17-26
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• 2016

본 논문에서는 무선 통신 시스템 및 휴대용 비디오 처리 시스템과 같은 다양한 시스템 반도체 응용을 위한 12비트 60MS/s 0.18um CMOS Flash-SAR ADC를 제안한다. 제안하는 Flash-SAR ADC는 고속으로 동작하는 flash ADC의 장점을 이용하여 우선 상위 4비트를 결정한 후, 적은 전력 소모를 갖는 SAR ADC의 장점을 이용하여 하위 9비트를 결정함으로써 해상도가 증가함에 따라 동작 속도가 제한이 되는 전형적인 SAR ADC의 문제를 줄였다. 제안하는 ADC는 전형적인 Flash-SAR ADC에서 고속 동작 시 제한이 되는 입력 단 트랙-앤-홀드 회로를 사용하지 않는 대신 SAR ADC의 C-R DAC를 단일 샘플링-네트워크로 사용하여 입력 샘플링 부정합 문제를 제거하였다. 한편, flash ADC에는 인터폴레이션 기법을 적용하여 사용되는 프리앰프의 수를 절반 수준으로 줄이는 동시에 SAR 동작 시 flash ADC에서 불필요하게 소모되는 전력을 최소화하기 위해 스위치 기반의 바이어스 전력 최소화 기법을 적용하였다. 또한 고속 동작을 위해 SAR 논리회로는 TSPC 기반의 D 플립플롭으로 구성하여 범용 D 플립플롭 대비 논리회로 게이트 지연시간을 55% 감소시킴과 동시에 사용되는 트랜지스터의 수를 절반 수준으로 줄였다. 시제품 ADC는 0.18um CMOS 공정으로 제작되었으며, 측정된 DNL 및 INL은 12비트 해상도에서 각각 최대 1.33LSB, 1.90LSB이며, 60MS/s 동작 속도에서 동적성능은 최대 58.27dB의 SNDR 및 69.29dB의 SFDR 성능을 보인다. 시제품 ADC의 칩 면적은 $0.54mm^2$이며, 1.8V 전원전압에서 5.4mW의 전력을 소모한다.

• Journal of Chest Surgery
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• 제12권1호
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• pp.16-22
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• 1979

Clinical evaluation of contact sensitization to 2, 4-dinitro-chlorobenzene [DNCB] was performed in 2 groups: group A [30 patients with non-malignant disease] and group B [30 patients with bronchogenic carcinoma]. Initial sensitization was elicited out by applying 2, 000 ug of DNCB to skin surface of the both group A and B. Subsequently a relatively weak challenge dose, 200 ug of DNCB, was applied 14 days later, showing the satisfactory results of sensitization with minimizing non-specific irritative inflammatory skin response. Delayed cutaneous hypersensitivity reactions shown by spontaneous flare phenomena appeared at the challenge site, and they were assessed 48 hours later. The reaction were graded from +1 to +4 according to the degree of flare or vesicular reaction. The results were as follows: 1. 28 cases [93%] of group A, however, only 18 cases [67%] of group B exhibited delayed cutaneous hypersensitivity reaction to DNCB contact sensitization [P<0.02]. 2. Of group A, the delayed cutaneous hypersensitivity reactions above +2 of DNCB score were 25 cases [83%], meanwhile 11 cases [37%] in group B [P<0.001]. 3. Undifferentiated carcinomas showed highest incidence of anergy to DNCB contact sensitization in the all histologic types of group B. 4. In group B, 8 [42%] of 19 cases who react to DNCB were resectable, whereas only 2 [18 %] of 11 cases who failed to react to DNCB were resectable for curative cancer surgery. These study suggests that cellular immune reaction of group B was depressed remarkably comparing with that of group A.

• 한국분말재료학회지
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• 제18권6호
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• pp.562-567
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• 2011

This paper reports the effect of sintering processes and additives on the microstructures and mechanical properties of $ZrB_2$-SiC composite ceramics. We fabricated sintered bodies of $ZrB_2$-20 vol.% SiC with or without sintering additive, such as C or $B_4C$, densified by spark plasma sintering as well as hot pressing. While almost full densification was achieved regardless of sintering processes or sintering additives, significant grain growth was observed in the case of spark plasma sintering, especially with $B_4C$. With sintered bodies, mechanical properties, such as flexural strength and Vickers hardness, were also examined.