• 마이크로전자및패키징학회지
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• 제12권2호
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• pp.175-179
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• 2005

본 논문에서는 평행 결합선로를 이용하여 구조가 간단하고 광대역 특성을 갖는 $180^{\circ}$ bit X-대역 위상 변이기를 설계하고 마이크로머시닝 (micromachining) 공정을 이용하여 제작하였다. 이 위상 변이 기는 한쪽 끝이 접지된 $90^{\circ}$ 평행 결합선로와 한쪽 끝이 단락된 $90^{\circ}$ 평행 결합선로를 병렬로 연결한 구조를 갖는다. 이분법 이론에 의해 $180^{\circ}$ bit 위상 변이기에 대한설계 공식을 유도하고, 이를 적용하여 중심주파수 10GHz에서 대역폭 6GHz, ${\pm}5^{\circ}$의 위상 변이를 갖는 광대역 $180^{\circ}$ bit위상 변이기를 설계, 제작하였다.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1989년도 춘계학술대회
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• pp.35-37
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• 1989

A new MR angiography technique using a composite sequence for the suppression of static sample signals is proposed and verified with experiments. When the composite [$90^{\circ}-{\tau}-180^{\circ}-2{\tau}-180^{\circ}-{\tau}$] sequence is applied, the large signal from the static sample is sufficiently suppressed but the signal from fresh inflow sample of which amplitude. is observed without suppression. These properties are appropriate for angiographic applications. In this paper, a modified line scan method (Block line scan angiography) incorporated with the composite [$90^{\circ}-{\tau}-180^{\circ}-2{\tau}-180^{\circ}-{\tau}$] sequence is used to obtain flow-only images, i.e., angiograms. The block line scan method improves the resolution in the flow-direction at the expense of imaging time. With the composite sequence, there is no need for subtraction procedure as in the most conventional angiographic methods. Experimental results for a phantom and a normal volunteer with KAIS 2.0 Tesla MRI system are shown.

• 대한핵의학회지
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• 제29권4호
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• pp.478-483
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• 1995

We compared the influences of reconstruction methods using $180^{\circ}$ or $360^{\circ}$ data upon contrasts and discriminating capability and diagnostic accuracy in $^{99m}Tc-MIBI$ stress/rest myocardial SPECT. We reviewed SPECT images reconstructed only with $180^{\circ}$ projection data or with $360^{\circ}$ data in 18 patients and in 11 normal subjects. To compare counts of surface structures and deep structures, we measured ape# posterior wall ratios in 11 normal subjects. To compare the contrasts of images, we measured apex/ventricle ratios. To compare contrasts between normal and diseased myocardial segments, we measured count ratios of defect and normal segments in 4 patients who had single coronary artery diseases. To compare diagnostic accuracy, we scored SPECT images made with $180^{\circ}$ and $360^{\circ}$ data segmentally. Sensitivity and specificity for the diagnosis of coronary artery disease and for the revelation of diseased arteries with both $180^{\circ}$ and $360^{\circ}$ SPECT images. If involved coronary arteries had more narrowing than 50% In coronary angiogram, we considered them as diseased arteries Apex/posterior wall ratios were not different significantly in normal subjects. Apex/ ventricle ratios in normal subjects were different significantly between $180^{\circ}$ and $360^{\circ}$ SPECT images. Defect/normal ratios were different significantly between $180^{\circ}$ and $360^{\circ}$ SPECT images in single vessel disease patients. The overall diagnostic accurracy was the same between $180^{\circ}$ and $360^{\circ}$ data collection. Sensitivity was 94% and specificity was 91% for both types of data collection in this sample population. Sensitivity and specificity of each coronary artery territory were not significantly different between the images made with $180^{\circ}$ and $360^{\circ}$ data. The images made with $180^{\circ}$ data had better contrast between ventricle and myocardium and between hypoperfused and normal myocardium, though no difference was found between the ratios of the myocardial counts of surface and deep structures. However, diagnostic sensitivities of diseased artery territories were not different significantly and so were overall diagnostic accuracy between both methods of making images with $180^{\circ}$ and $360^{\circ}$ data.

• 한국약용작물학회지
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• 제14권4호
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• pp.221-224
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• 2006

해가림의 이랑방향이 인삼의 생육에 미치는 영향을 구명하고자 방위각 $90^{\circ}$와 $270^{\circ}$ (이랑방향 $90^{\circ}$), $120^{\circ}$와 $300^{\circ}$ (이랑방향 $120^{\circ}$), $0^{\circ}$와 $180^{\circ}$ (이랑방향 $180^{\circ}$)를 가로지르는 방향으로 이랑을 만들고 2, 3년생 인삼의 생육특성 및 수량성을 표준재배법의 이랑방향 $120^{\circ}$와 비교한 결과는 다음과 같다. 1. 이랑방향 $90^{\circ}$는 대조구인 $120^{\circ}$에 비해 오전에 투광량의 감소로 해가림 내 기온은 약간 낮았으나 15시 이후에는 투광량의 증가로 대조구보다 높은 기온을 보였다. 2. 이랑방향 $180^{\circ}$는 대조구인 $120^{\circ}$에 비해 $9:00{\sim}11:00$ 사이에 투광량의 현저한 증가로 해가림 내 기온이 매우 높았으나 13시 이후에는 대조구와 투광량이 비슷하여 기온도 큰 차이가 없었다. 3. 이랑방향 $90^{\circ}$와 $180^{\circ}$에서 경장, 엽장 및 엽폭은 대조구인 $120^{\circ}$보다 모두 감소되었는데, $90^{\circ}$보다 $180^{\circ}$에서의 감소가 현저하였다. 4. 엽소율(葉燒率)은 이랑방향 $90^{\circ}$에서 가장 작고 직사광선의 유입이 많았던 $180^{\circ}$에서 가장 컸으며 해에 따라 엽소율(葉燒率)은 큰 변이를 보였다. 5. 2004년과 같이 한발이 심한 해에는 이랑방향 $180^{\circ}$의 수량성이 대조구인 $120^{\circ}$보다 낮았으나 상대적으로 한발이 적은 2005년도에는 $180^{\circ}$가 대조구보다 높은 수량을 보였다.

• ETRI Journal
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• 제33권1호
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• pp.13-17
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• 2011

A highly miniaturized on-chip $180^{\circ}$ hybrid employing periodic ground strip structure (PGSS) was realized on a silicon radio frequency integrated circuit. The PGSS was placed at the interface between $SiO_2$ film and silicon substrate, and it was electrically connected to top-side ground planes through the contacts. Owing to the short wavelength characteristic of the transmission line employing the PGSS, the on-chip $180^{\circ}$ hybrid was highly miniaturized. Concretely, the on-chip $180^{\circ}$ hybrid exhibited good radio frequency performances from 37 GHz to 55 GHz, and it was 0.325 $mm^2$, which is 19.3% of a conventional $180^{\circ}$ hybrid. The miniaturization technique proposed in this work can be also used in other fields including compound semiconducting devices, such as high electron mobility transistors, diamond field effect transistors, and light emitting diodes.

• Journal of Advanced Marine Engineering and Technology
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• 제24권6호
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• pp.15-23
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• 2000

In the present study, flow characteristics of turbulent pulsating flow in the square-sectional $180^{\circ}$curved duct are investigated experimentally. In order to measure axial direction velocity and secondary flow distributions, experimental studies for air flow are conducted in the square-sectional $180^{\circ}$curved duct by using the LDV system with the data acquisition and the processing system of the Rotating Machinery Resolver (RMR) and the PHASE software. The experiment is conducted on seven sections form the inlet($\phi=0^{\circ}$) to the outlet($\phi=180^{\circ}$) at $30^{\circ}$intervals of the duct. The results obtained from the experimentation are summarized as follows : In the axial direction velocity distributions of turbulent pulsating flow, when the ratio of velocity amplitude (A1) is less than one, there is hardly any velocity change in the section except near the wall and in axial velocity distribution along the phase. The secondary flow of turbulent pulsating flow has a positive value at the bend angle of $150^{\circ}$regardless of the ratio of velocity amplitude. The dimensionless value of secondary flow becomes gradually weak and approaches zero in the region of bend angle $180^{\circ}$without regard to the ratio of velocity amplitude.

• Journal of Advanced Marine Engineering and Technology
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• 제25권1호
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• pp.131-138
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• 2001

In this paper, an experimental investigation of characteristics of developing turbulent steady flows in a square-sectional $180^{\circ}$curved duct is presented. The experimental study using air in a square-sectional $180^{\circ}$ curved duct carryed out to measure axials direction velocity and wall shear stress distrbutions by using Laser Dopper Velocimeter(LDV) system with data acquistion and processing the system of FIND6260 softwere at 7 sections from the inlet($\phi=0^{\circ}$) to the outlet($\phi=180^{\circ}$) in $301^{\circ}$ intervals of a curved duct.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2000년도 춘계학술대회 논문집(Proceeding of the KOSME 2000 Spring Annual Meeting)
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• pp.127-133
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• 2000

In the present study flow characteristics of turbulent pulsating flow in a square-sectional 180。 curved duct are investigated experimentally. in order to measure axial velocity and secondary flow distributions experimental studies for air flow are conducted in a square-sectional $180^{\circ}$ curved duct by using the LDV system with the data acquisition and the processing system of the Rotating Machinery Resolver (RMR) and the PHASE software. The experiment is conducted on seven sections form the inlet(${\phi}=180^{\circ}$) at $30^{\circ}$ intervals of the duct. The results obtained from the experimentation are summarized as follows : In the axial velocity distributions of turbulent pulsating flow when the ratio of velocity amplitude(A1) is less than one there is hardly any velocity change in the section except near the wall and any change in axial velocity distribution along the phase. The secondary flow of turbulent pulsating flow has a positive value at the vend angle of $150^{\circ}$ without regard to the ratio of velocity amplitude. The dimensionless value of secondary flow becomes gradually weak and approaches zero in the region of bend angle $180^{\circ}$ without regard to the ratio of velocity amplitude.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2012년도 춘계학술대회 논문집
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• pp.1061-1062
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• 2012

• 한국식생활문화학회지
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• 제31권6호
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• pp.643-651
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• 2016

This study was investigated the difference in the quality characteristics of the fermented soybean roasted with different conditions for making chungyukjang. Roasted condition of soybean was decided by pre-test, which was on $140^{\circ}C$ for 21 min, $180^{\circ}C$ 9.5 min, and $220^{\circ}C$ 6 min. Fermented soybean with different roasted condition and conventionally made cheonggukjang were measured for proximate composition, color, pH, amino nitrogen, ammonia nitrogen, free sugar and amino acids. The lightness and yellowness of soybean fermented by conventional method was higher than those of the fermented soybean with roasted soybean. The contents of free sugar of fermented soybean roasted on $220^{\circ}C$ for 6 min (FS220) was the highest among the group and followed by fermented soybean roasted on $180^{\circ}C$ for 9.5 min (FS180), $140^{\circ}C$ 21 min (FS140) and conventional cheonggukjang (FS0). The contents of total free amino acid was highest on fermented soybean roasted on $140^{\circ}C$ for 21 min (FS140) and followed by fermented soybean roasted on $180^{\circ}C$ for 9.5 min (FS180), $220^{\circ}C$ 6 min (FS220) and conventional cheonggukjang (FS0).