A 70 dB SNDR 10 MS/s 28 nm CMOS Nyquist SAR ADC with Capacitor Mismatch Calibration Reusing Segmented Reference Voltages

Ho-Jin Kim,Jun-Ho Boo,Jae-Hyuk Lee,Jun-Sang Park,Tai-Ji An,Sung-Han Do,Young-Jae Cho,Michael Choi,Gil-Cho Ahn,Seung-Hoon Lee 대한전자공학회 2021 Journal of semiconductor technology and science Vol.21 No.6

This paper proposes a calibrated 14-bit 10 MS/s 28 nm CMOS Nyquist successive-approximation register (SAR) analog-to-digital converter (ADC). The upper 9 bits and the remaining lower 5 bits are determined, respectively, using a binary-weighted capacitor array and segmented reference voltages divided from a simple resistor string. While the proposed calibration is applied only to the critical most significant 4-bit capacitors, the segmented reference voltages to decide the lower 5 bits are reused via a unit capacitor. This creates a small weight on the calibration digital-to-analog converter (DAC) in place of making an adjustment to the small-sized actual capacitor value. The proposed calibration does not require extra capacitors smaller than the unit capacitor, reducing the chip area and circuit complexity. The comparator employs a noise-reduction capacitor, enabling it to realize low-noise performance with low-power. The prototype ADC in a 28 nm CMOS occupies an active die area of 0.062 ㎟ and consumes 351 μW at a 1.0 V supply voltage. After calibration, the prototype ADC shows a measured differential non-linearity (DNL) and integral non-linearity (INL) within 1.59 LSB and 2.92 LSB, respectively, at 14 bits with a maximum signal-to-noise-and-distortion ratio (SNDR) and spurious-free dynamic range (SFDR) of 70.0 dB and 85.0 dB at 10 MS/s, respectively.

Cynara scolymus L. Inhibits the LPS-induced Inflammatory Reaction via Suppression of NF-κB Activity in RAW 264.7 Cells

Kyung-Jun Boo(Kyung-Jun Boo),Kiman Lee(Kiman Lee),Il-Ho Park(Il-Ho Park),Tae Jin Kang(Tae Jin Kang) 대한약학회 2023 약학회지 Vol.67 No.1

Cynara scolymus L. (artichoke) has been traditionally used in the treatment of digestive-related disease, severe hyperlipidemia and liver disease. Recently, anti-inflammatory effect of artichoke has been reported by several studies, but its mechanisms are still unclear. In this study, the anti-inflammatory mechanism of artichoke was studied using an in vitro acute inflammation model. The effect of artichoke on the expression of pro-inflammatory cytokines, such as interleukin- 1beta (IL-1β), IL-6, and tumor necrosis factor-alpha (TNF-α) in murine macrophage cell line, RAW264.7, was examined by using ELISA and RT-PCR. As a result, artichoke inhibited the expression of IL-1β, IL-6 and TNF-α in macrophages activated by lipopolysaccharide (LPS) at a dose dependent manner. The expression of inflammatory mediators such as NO and PGE2 was next investigated in RAW264.7 cells stimulated with LPS. Artichoke also inhibited the production of NO and PGE2 in the cells at a dose dependent manner. Artichoke suppressed the mRNA expression of iNOS and COX-2 in macrophages by LPS. The effect of artichoke on the activation of NF-κB was examined and LPS-induced NF-κB activation was decreased by treatment of artichoke, suggesting that artichoke has anti-inflammatory effect by inhibiting NF- κB activation.

Enhancement of osteopromotion with synthetic oligopeptide domain coated anorganic bovine hydroxyapatite

( Jun Beom Park ),( Ho Nam Park ),( Yoon Jeong Park ),( Yang Jo Seol ),( Sang Cheol Lee ),( Kyoung Hwa Kim ),( Tae Il Kim ),( Yong Moo Lee ),( Young Ku ),( In Chul Rhyu ),( Soo Boo Han ),( Chong Pyoun 대한치주과학회 2005 대한치주과학회 학술대회자료집 Vol.2005 No.2

Effects of Ginsenosides and Their Metabolites on Voltage-dependent Ca2+ Channel Subtypes

Jun-Ho Lee,Sang Min Jeong,Jong-Hoon Kim,Byung-Hwan Lee,In-Soo Yoon,Joon-Hee Lee,Sun-Hye Choi,Sang-Mok Lee,Yong-Sun Park,이정하,Sung Soo Kim,Hyoung-Chun Kim,Boo-Yong Lee,Seung-Yeol Nah 한국분자세포생물학회 2006 Molecules and cells Vol.21 No.1

In previous reports we demonstrated that ginsenosides, active ingredients of Panax ginseng, affect some subsets of voltage-dependent Ca2+ channels in neuronal cells expressed in Xenopus laevis oocytes. However, the major component(s) of ginseng that affect cloned Ca2+ channel subtypes such as α1C (L)-, α1B (N)-, α1A (P/Q)-, α1E (R)- and α1G (T) have not been identified. Here, we used the two-microelectrode voltage clamp technique to characterize the effects of ginsenosides and ginsenoside metabolites on Ba2+ currents (IBa) in Xenopus oocytes expressing five different Ca2+ channel subtypes. Exposure to ginseng total saponins (GTS) induced voltage-dependent, dose-dependent and reversible inhibition of the five channel subtypes, with particularly strong inhibition of the α1G-type. Of the various ginsenosides, Rb1, Rc, Re, Rf, Rg1, Rg3, and Rh2, ginsenoside Rg3 also inhibited all five channel subtypes and ginsenoside Rh2 had most effect on the α1C- and α1E-type Ca2+ channels. Compound K (CK), a protopanaxadiol ginsenoside metabolite, strongly inhibited only the α1G-type of Ca2+ channel, whereas M4, a protopanaxatriol ginsenoside metabolite, had almost no effect on any of the channels. Rg3, Rh2, and CK shifted the steady-state activation curves but not the inactivation curves in the depolarizing direction in the α1B- and α1A-types. These results reveal that Rg3, Rh2 and CK are the major inhibitors of Ca2+ channels in Panax ginseng, and that they show some Ca2+ channel selectivity.

nitrogen

Boo, Chang Ho,U. Zang Kual,Song, Sung Jun 제주대학교 방사능이용연구소 1998 연구보고 Vol.12 No.-

양액 재배에서 서양 심비디움(Cymbidium Jungfrau)의 질소와 인 흡수 및 재분배양상을 조사하였고 양액 재배와 관행인 화분 재배간의 심비디움의 생육, 광합성, 엽록소 함량, 무기물 함량을 비교하였다. 질소(???)의 흡수는 자연광의 60% 광도에서 보다 자연광에서 많았고, 인(???)의 흡수는 이와 반대의 경향을 나타냈다. 흡수된 질소(???)는 벌브에 가장 많이 존재하였고 인(???)은 뿌리와 벌브에 많이 있었으며 잎으로 재분배된 양은 10% 정도였다. 2년생 어미주 보다는 0.5 또는 1년생 새끼주에서 질소(???)와 인(???)의 흡수가 더 많았다. 심비디움의 인 흡수율은 보리의 경우 보다 약 130배정도 낮았다. 심비디움의 초장, 벌브 크기, 생체증가율, 광합성 능, 엽록소 함량은 바크 또는 락울을 배지로 이용하는 양액 재배가 일반 관행재배보다 더 높았다. 특히, 양액 재배에서 사용된 바크와 락울간에 생육과 무기물함량이 차이를 보이지 않았는데, 이는 바크 배지에서 양액의 분산을 용이하도록 6개의 구멍이 뚫린 튜브로 양액을 관주했기 때문이라고 생각된다. 또한, 질소, 인, 칼륨, 마그네슘의 함량은 양액 재배에서 높았으나 칼슘은 관행과 차이가 없었고 무기물의 흡수는 주로 영양생장기간 동안에 이루어졌다. N(??N) and P(??P) absorption by 2 year-old Cymbidium Jungfrau in solution culture were investigated. Growth, photosynthesis, chlorophyll content and mineral composition of Cymbidium in the solution culture with bark or granular rockwool were compared with these parameters in the conventional pot culture. Nitrogen absorption by Cymbidium was higher in full sunlight than in 60% of sunlight while P absorption was higher in 60% of sunlight. 67% of N absorbed in plant was redistributed to the bulb (39%) and leaves (28%) while 46% of P absorbed was found in the bulb (36.2%) and leaves (10.2%). Accumulation of P in leaves was 3-fold lower than that of N. Nitrogen and P absorption in 0.5 or 1 year-old daughter plant growing vigorously were greater than in immature daughter or mother plant. The absorption rate of phosphorus in Cymbidium was 130-fold lower than that of barley. Greater shoot length and bulb diameter, and higher fresh weight, photosynthesis and chlorophyll content were observed in the solution culture than in the conventional pot culture. Solution culture had also more content of N, P, K and Mg but Ca in leaves, bulb and root than conventional pot culture but did not that of Ca. A large part of the nutrient absorption was occurred during vegetative growth. Also, There was no difference between bark and rockwool in the solution culture due to the improvement of poor dispersion of nutrient solution in bark.

적외선 스테레오 카메라를 이용한 고속 이동객체의 위치에 대한 확률모델

오준호(Jun Ho Oh),이상화(Sang Hwa Lee),이부환(Boo Hwan Lee),박종일(Jong-Il Park) 대한전자공학회 2015 전자공학회논문지 Vol.52 No.1

본 논문에서는 비냉각방식 적외선 스테레오 카메라 시스템을 이용하여 고속으로 이동하는 고온의 소형 물체의 3차원 위치를 추정함에 있어서 무작위로 추정되는 그 위치를 확률 모델로 표현하는 방법을 제안한다. 본 논문에서 제안하는 확률적 위치 모델은 디지털 영상으로 인한 픽셀위치의 오차(pixel position error)와 비냉각식 적외선 카메라에서 영상을 취득하는 순간의 차이에 의한 지터오차(jitter error)로부터 유도되는데, 두 가지 오차를 결합한 통합 오차확률모델을 수학적으로 제시하고 실험을 통하여 그 효용성을 보여준다. 우선 본 논문에서 고안한 적외선 카메라의 지터 측정기를 이용하여 적외선 카메라에서 발생하는 타이밍 지터를 통계적으로 관찰하여 확률모델을 설정한다. 또한 디지털 영상의 스테레오 정합 과정에서 발생하는 픽셀 오차에 의하여 정확도가 떨어지는 측정거리를 확률모델로 정의한다. 실험 측정 결과, 지터는 가우시안 확률분포로 모델링하는 것이 가능하며, 픽셀오차는 균일 확률분포로 모델링된다. 이 두 가지 확률분포를 갖는 오차는 상호 독립으로서 선형 결합되는데, 전체 오차에 대한 확률분포는 지터오차 변수의 확률분포와 픽셀위치오차 변수의 확률분포를 컨볼루션함으로써 유도된다. 실제 고속 이동체에 대하여 정밀한 3차원 궤적측정기와 자체 구현한 적외선 스테레오 카메라 시스템을 이용하여 제안한 확률모델을 3차원 위치추적 실험에 적용한 결과 95% 신뢰도 구간에서 물체의 위치를 추정하는 것을 확인하였다. 즉, 물체의 위치를 정확하게 측정하는 것은 이론적으로는 불가능하며, 확률모델을 통하여 물체의 위치를 표현하는 것이 타당함을 확인할 수 있다. 본 논문에서 제안한 확률모델은 적외선 스테레오 카메라를 이용한 거리측정에서 부정확함을 확률적으로 모델링하여 위치정보에 대한 불확실성을 보정해주며, 특히 적외선 스테레오 카메라를 이용한 고속 물체의 위치추적 및 거리측정에서 이론적, 실험적 토대를 제공할 것으로 기대된다. This paper proposes a statistical model of 3-D positions when tracking moving targets using the uncooled infrared (IR) stereo camera system. The proposed model is derived from two errors. One is the position error which is caused by the sampling pixels in the digital image. The other is the timing jitter which results from the irregular capture-timing in the infrared cameras. The capture-timing in the IR camera is measured using the jitter meter designed in this paper, and the observed jitters are statistically modeled as Gaussian distribution. This paper derives an integrated probability distribution by combining jitter error with pixel position error. The combined error is modeled as the convolution of two error distributions. To verify the proposed statistical position error model, this paper has some experiments in tracking moving objects with IR stereo camera. The 3-D positions of object are accurately measured by the trajectory scanner, and 3-D positions are also estimated by stereo matching from IR stereo camera system. According to the experiments, the positions of moving object are estimated within the statistically reliable range which is derived by convolution of two probability models of pixel position error and timing jitter respectively. It is expected that the proposed statistical model can be applied to estimate the uncertain 3-D positions of moving objects in the diverse fields.

Model for thermal conductivities in spun yarn carbon fabric composites

Seo, Boo Ho,Cho, Young Jun,Youn, Jae Roun,Chung, Kwansoo,Kang, Tae Jin,Park, Jong Kyoo Wiley Subscription Services, Inc., A Wiley Company 2005 Polymer composites Vol.26 No.6

<P>A study on the thermal conductivities of spun yarn-type carbon/phenolic (spun C/P) composites using a thermal-electrical analogy method is presented. This method is based on the similarity between the partial differential equation that governs the thermal potential and electrical potential distribution. The unit cell of a laminate composite is divided into several conduction elements. By constructing an equivalent thermal resistance network in series, and in parallel based on analogy, we were able to predict the thermal conductivity of the composite. The prediction values obtained from the model are compared with known thermal conductivities on a carbon/epoxy composite with an eight-harness satin (8HS) texture. It is shown that the model provides a good estimate of the thermal conductivity of the spun yarn fabric-reinforced composite. With the use of this model, the thermal conductivity of the spun C/P composites with 8HS was validated experimentally. Good agreement was found between the present approach and the experimental results. POLYM. COMPOS., 26:791–798, 2005. © 2005 Society of Plastics Engineers</P>

A 97.7-dB DR 12.3-μW 1-kHz Bandwidth 2nd Order Delta-sigma Modulator with a Fully Differential Class-AB Op-Amp using Floating Class-AB Control

Byeong-Ho Yu,Jun-Ho Boo,Jae-Geun Lim,Hyoung-Jung Kim,Jae-Hyuk Lee,Gil-Cho Ahn 대한전자공학회 2023 Journal of semiconductor technology and science Vol.23 No.5

This paper presents a 2nd order modified feed-forward (FF) delta-sigma modulator. To reduce power consumption, the proposed analog-to-digital converter (ADC) adopts a class-AB op-amp for the first integrator since it shows an enhanced slew rate with low quiescent current. In addition, a 4-bit asynchronous successive approximation register (SAR) ADC which exhibits low power consumption is employed as a quantizer. A delay is incorporated into the feedback path for stable operation of the feedback loop. The prototype ADC is fabricated in a 28 nm CMOS process, and the core area is 0.095 mm2. It consumes 12.3 μW from 0.8 V (Analog)/0.85 V (Digital) supply voltages at an operating clock frequency of 512 kHz with an oversampling ratio (OSR) of 256. It achieves a dynamic range (DR) of 97.7 dB and a peak signal-to-noise and distortion ratio (SNDR) of 94.8 dB, corresponding to a Schreier figure-of-merit (FoM) of 176.8 dB.

Tolfenamic Acid Suppresses Inflammatory Stimuli-Mediated Activation of NF-κB Signaling

( Hong Jun Shao ),( Zhi Yuan Lou ),( Jin Boo Jeong ),( Kui Jin Kim ),( Ji Hye Lee ),( Seong Ho Lee ) 한국응용약물학회 2015 Biomolecules & Therapeutics(구 응용약물학회지) Vol.23 No.1

Tolfenamic acid (TA) is a traditional non-steroid anti-inflammatory drug (NSAID) and has been broadly used for the treatment of migraines. Nuclear factor kappa B (NF-κB) is a sequence-specific transcription factor and plays a key role in the development and progression of inflammation and cancer. We performed the current study to investigate the underlying mechanisms by which TA suppresses inflammation focusing on NF-κB pathway in TNF-α stimulated human normal and cancer cell lines and lipopolysaccharide (LPS)-stimulated mouse macrophages. Different types of human cells (HCT116, HT-29 and HEK293) and mouse macrophages (RAW264.7) were pre-treated with different concentrations of TA and then exposed to inflammatory stimuli such as TNF-α and LPS. Transcriptional activity of NF-κB, IκB-α-degradation, p65 translocation and mitogen-activated protein kinase (MAPK) activations were measured using luciferase assay and Western blots. Pre-treatment of TA repressed TNF-α- or LPS-stimulated NF-κB transactivation in a dose-dependent manner. TA treatment reduced degradation of IκB-α and subsequent translocation of p65 into nucleus. TA significantly down-regulated the phosphorylation of c-Jun N-terminal kinase (JNK). However, TA had no effect on NF-κB signaling and JNK phosphorylation in HT-29 human colorectal cancer cells. TA possesses anti-inflammatory activities through suppression of JNK/NF-κB pathway in different types of cells.

인위적 입도조정에 따른 지반의 강도특성 변화

문준호(Jun-Ho Moon),신진화(Zhen-Hua Xin),김갑부(Gab-Boo Kim),문선미(Sun-Mi Moon),김영욱(Young-Uk Kim) 한국산학기술학회 2018 한국산학기술학회논문지 Vol.19 No.1

일반적으로 지반의 강도가 강한 지반은 입도분포가 양호하다고 예상할 수 있다. 그러나 Gap입도로 이루어진 지반으로 입도분포가 불량하더라도 지반의 강도가 강한 경우가 있다. 본 연구에서는 이와 같은 사실에 근거하여 인위적으로 조성한 Gap 입도시료와 입도분포가 균일한 시료, 양호한 시료를 직접전단시험을 통하여 지반의 강도정수를 구하고 이를 비교 분석하였다. 또한 13mm 골재와 19mm 골재를 이용한 평판재하시험으로 확대 적용하여 현장 적용성과 입도에 따른 강도 변화의 재현성을 확인하였다. 실험 결과 입자크기비와 내부마찰각이 상관관계가 있음을 확인 할 수 있었고, 특정한 입자 크기비의 범위에서 전단저항각이 상당히 커지는 것을 알 수 있었다. 또한 평판재하시험으로 극한지지력을 산정한 결과 입도조정법이 강도증가율에 크게 영향을 미치는 것을 알 수 있다. 따라서 위의 직접전단 시험을 통한 시험적 검증과 평판재하시험을 통한 재현성 확인을 통해 입도분포가 좋지 않음에도 간단한 입도 조정만으로 지반의 강도 증진을 유도할 수 있었다. In this study, an artificially formed Gap graded soil, designed to increase its shear strength, was analyzed to determine the strength parameters through direct shear tests. Uniform and fine grain size samples were compared to the Gap graded soil to investigate the increase in the shear strength. Plate loading tests were conducted using 13mm and 19mm aggregates to confirm the reproducibility of the strength enhanced samples for site application. This test confirmed that the particle size ratio and the internal friction angle are correlated to the shear strength, and the shear resistance angle significantly increased in the specific particle size ratio range. The calculation of the ultimate bearing capacity by the plate load test demonstrated that the grain size adjustment method greatly influences the strength increase rate. Therefore, the findings were verified and it was confirmed that a high shear strength is achievable despite the existence of a poor particle size distribution.