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      • KCI등재

        Differential X-ray Phase-contrast Imaging with a Grating Interferometer Using a Laboratory X-ray Micro-focus Tube

        윤권하,유종현,정창원,류철우,김영조,권영만,박미란,조승룡,천권수 한국물리학회 2014 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.65 No.12

        X-ray phase-contrast imaging can provide images with much greater soft-tissue contrast thanconventional absorption-based images. In this paper, we describe differential X-ray phase-contrastimages of insect specimens that were obtained using a grating-based Talbot interferometer and alaboratory X-ray source with a spot size of a few tens of micrometers. We developed the interferometeron the basis of the wavelength, periods, and height of the gratings; the field of view depends onthe size of the grating, considering the refractive index of the specimen. The phase-contrast imageswere acquired using phase-stepping methods. The phase contrast imaging provided a significantlyenhanced soft-tissue contrast compared with the attenuation data. The contour of the sample wasclearly visible because the refraction from the edges of the object was strong in the differentialphase-contrast image. Our results demonstrate that a grating-based Talbot interferometer with aconventional X-ray tube may be attractive as an X-ray imaging system for generating phase images. X-ray phase imaging obviously has sufficient potential and is expected to soon be a great tool formedical diagnostics.

      • KCI등재후보

        고주파열치료 후보에서의 간전이암의 검출: 이중시기 나선식 CT 영상과 지연기 펄스역전하모닉 영상의 비교$^1$

        윤권하,김은아,박기한,정선관,원종진,Yun, Gwon-Ha,Kim, Eun-A,Park, Gi-Han,Jeong, Seon-Gwan,Won, Jong-Jin 대한영상의학회 2002 대한영상의학회지 Vol.46 No.2

        목적: 간전이암 환자에서 고주파열치료 시행 전 전이성 종양의 수를 평가하는 데 있어서, 나선식 CT와 초음파 조영제 투입 후 지연기에 얻은 펄스역전하모닉 영상을 비교하고자 하였다. 대상과 방법: 나선식 CT상 직결장암의 간전이로 진단된 환자들 중 고주파열치료를 고려한 21명의 환자에 대해 시술 전 초음파 검사를 시행하였다. 초음파 조영제 SH U 508 A 4.0 g을 300 mg/mL의 농도로 정맥주입한 5분 후 지연기 펄스역전하모닉 영상을 얻었다. 나선식 CT와 초음파 영상 각각에서 전이성 종양의 수를 평가하였고, 두 검사에서 검출된 종양의 수에 통계적으로 차이가 있는지 알아보았다. 그리고 초음파 검사 결과가 환자의 치료방침에 미치는 영향에 대해 알아보았다. 결과: CT 검사에서는 21명의 환자에서 48개의 전이암이 검출되었고, 지연기펄스역전하모닉 영상에서는 56개가 검출되었다. 초음파 검사에서 CT 검사에 비해 6명(28%)에서 8개의 병변이 더 검출되었고, 이들 병변의 크기는 3-13 mm(평균, 7.2 mm)였다. 병변이 추가로 발견된 6명 중 3명에서는 초음파상 6개 이상의 종양이 검출되어 고주파열치료를 포기하였고, 5개 이하가 검출된 다른 3명에서는 추가로 발견된 병변까지 모두 소작하였다. 결론: 지연기 펄스역전하모닉 영상은 간전이암의 검출에 있어서 나선식 CT 영상에 대해 보완적인 검사로 유용하며, 간전이암에 대해 고주파열치료를 고려하는 환자에서 치료방침을 세우는 데 있어서 도움을 줄 수 있다고 생각한다. Purpose: To compare dual-phase helical CT and pulse inversion harmonic US using microbubble contrast agents in the detection of hepatic metastases prior to radiofrequency (RF) ablation. Materials and Methods: Twenty-one patients in whom hepatic metastases from colorectal cancer had been diagnosed by dual-phase CT scanning and who were considered to be candidates for RF ablation underwent pulse-inversion barmonic US examination. Images were obtained 5 minutes after the bolus injection of microbubble contrast agent SH U 508 A (4.0 g, 300 mg/mL). The number of metastatic tumors revealed by CT and US was determined, and the findings were statistically analysed. The influence of the results of US examination on treatment planning was also evaluated. Results: In 21 patients, 48 metastatic lesions were detected by helical CT, and 56 lesions by US. These eight additional lesions revealed by US occurred in six patients (29%), and their diameter was 3-13 (mean, 7.2) mm. In three of these patients, RF ablation could not be performed, while in the other three, the additional lesions were ablated. Conclusion: Pulse-inversion harmonic US imaging using microbubble contrast agents may depict small hepatic metastatic tumors that were not apparent at CT. US-therefore appears to be useful in the planning of treatment prior to the RF ablation of hepatic metastases.

      • KCI등재

        한국어 중급 교재 연어에 대한 어휘함수 기반 분석

        윤권하 ( Yoon Gwon-ha ),이선웅 ( Yi Seon-ung ) 연세대학교 언어정보연구원(구 연세대학교 언어정보개발원) 2017 언어사실과 관점 Vol.42 No.-

        This paper aims to classify and categorize collocations in five kinds of intermediate level Korean textbooks and workbooks, based on the lexical function by Mel'cuk. To speak Korean fluently and properly, it is necessary to understand grammar and vocabulary enough. The meanings of most words are very clear, they are easy to memorize and acquire. But collocations are hard to memorize and acquire, because the meanings of A+B are changed into A+B=A'+B or A+B=A+B' generally. To classify and categorize collocations, simple standard lexical function which is made by Mel'cuk is useful, because simple standard lexical function classify according to syntactic and meaning standard. Korean textbooks and workbooks are the best materials in analyzing Korean collocations, because foreign Korean learners them in their class. After analyzing collocations in Korean intermediate 5 kinds of 30 textbooks based on lexical function, I found that the number of lexical functions of all collocations is 24 and that the lexical functio of Oper, Func, Real appears at a high rate. Because Oper, Func are the lexical function related support verb, it is naturally said that the form of ‘predicative noun + support verb’ is most common in Korean collocations. And I showed characteristics of collocations in 5 kinds of textbooks & workbooks with regard to lexical functions.

      • KCI등재

        췌장선암: 이중시기 나선식 CT와 수술소견 및 병리조직학적 소견의 비교

        김은아,윤권하,박성훈,윤기중,원종진,Kim, Eun-A,Yun, Gwon-Ha,Park, Seong-Hun,Yun, Gi-Jung,Won, Jong-Jin 대한영상의학회 2003 대한영상의학회지 Vol.48 No.3

        목적: 췌장선암의 절제가능성 평가에 이중시기 나선식 CT의 정확도에 대하여 알아보고 CT소견과 수술소견 및 병리조직소견을 비교하고자 하였다. 대상과 방법: 이중시기 나선 CT를 시행하였던 병리적으로 확진된 30명의 췌장선암 환자 중 두부 췌장암으로 수술을 시행한 17명에서 종양의 수술적 절제가능성을 평가하였다. 나선식 CT는 동맥기 영상과 문맥기 영상을 얻었으며, 2예에서 단일평면 역동적(single-level dynamic)CT를 얻었다. CT소견을 수술소견 및 병리조직소견과 비교분석하였다. 결과: 수술 결과 17명의 환자 중 13명(76%)의 환자는 절제가능하였으며,네명은 불가능하였다. 절제 가능하였던 종양의 평균크기는 동맥기 2.76 cm, 문맥기 2.32 cm 병리검사상 2.48 cm으로 측정되었으며, 절제가능성 평가에 있어서 나선식 CT의 정확도는 87%였다. 종양의 중심부위는 모든 환자의 동맥기 영상과 문맥기 영상에서 저음영이었으며, 종양의 주변부는 동맥기에서는 저음영으로, 문맥기에서는 10명에서 등음영, 3명에서 고음영으로 관찰되었다. 단일평면 역동적 CT에서 종양의 중심부는 지속적으로 저음영으로, 주변부는 점차적으로 조영 증강되는 소견이 관찰되었다. CT소견과 병리조직 검사를 비교해 보았을 때 중심부의 저음영 부위는 종양 세포, 괴사상태(3예)그리고 점액질(4예)이었으며, 주변부의 등등도 또는 고음영 부위는 섬유질과 염증세포의 침윤이 있었다. 조직학적 검사상 11예에서 췌장 주변부 지방조직의 종양세포침윤이 관찰되었으며, 7예에서 췌장 주변 주요혈관의 미세현미경적 침윤이 있었다. 결론: 이중시기 나선식 CT는 췌장암의 환자에 있어서 절제가능성 평가에 도움을 주며, CT 소견은 췌장암의 병리조직학적 소견을 잘 반영한다고 생각된다. Purpose: To determine the accuracy of dual-phase helical CT in assessing the resectability of pancreatic ductal adenocarcinoma, and to correlate the CT findings with the surgical and histopathologic findings. Materials and Methods: Thirty patients with pathologically proven cancer of the pancreas underwent arterialand portal- phase helical CT scanning, and in two of these, single-level dynamic CT was performed during celiac and superior mesenteric arteriography. In 17 patients who underwent surgery for potentially resectable cancer of the pancreatic head, tumor resectability was assessed. The CT findings were analyzed and correlated with these of surgery and histopathology. Results: In 13 (76%) of the 17 patients who underwent surgery, tumors were resectable. Their average size was 2.76 cm (arterial phase), 2.30 cm (portal phase), and 2.48 cm (pathologically determined) and the overall accuracy of helical CT for assessing resectability was 87%. In all patients, the central portion of the tumors exhibited hypoattenuation at both phases; the peripheral portion showed hypoattenuation at the arterial phase and iso- (n=10) or hyperattenuation (n=3) at the portal phase. Single-level dynamic CT depicted a persistently ypoattenuating central portion and progressive and prolonged enhancement of the periphery. CT-histopathologic correlation showed that central hypoattenuation indicated the presence of tumor cells, necrosis (n=3) and mucin (n=4), while the peripheral iso- or hyperattenuated areas seen at the portal phase represented fibrosis and inflammatory infiltration. Histopathologic examination revealed tumoral infiltration of peripancreatic fat tissue (n=11) and microvascular invasion of major peripancreatic vessels (n=7). Conclusion: The dual-phase helical CT is useful in the determination of resectability in pancreas cancer and CT findings represent well the histopathologic features of pancreas cancer.

      • KCI등재

        마이크로-CT를 이용한 흰쥐 신장의 미세혈관구조 관찰

        유승현,윤권하,서일영 대한비뇨의학회 2008 Investigative and Clinical Urology Vol.49 No.8

        Purpose: Rodent models that mimic human renal diseases are being increasingly recognized as powerful tools in the development of new drugs and for evaluating the efficacy of novel therapeutics in a preclinical setting. However, there are few reports on microvasculature imaging of the urinary system in small animals. An experimental study was performed to evaluate the microvasculature in a rat kidney using micro- computed tomography(CT) with three-dimensional images. Materials and Methods: Five Sprague-Dawley male rats(age: 10-12 weeks, weight: 200-250g) underwent a laparotomy under anesthesia with an intramuscular injection of 0.5cc xylazine hydrochloride and ketamine mixed solution(1:10). After ligation of the abdominal aorta and inferior vena cava immediately above the renal artery, a 24 gazed catheter was inserted into the abdominal aorta. A physiological solution and heparin(500U) were infused through the catheter to flush the blood from the renal vasculature. The kidney was enhanced using self-made contrast material. The excised kidney was frozen for the micro-CT scan. Results: The mean longitudinal diameter and weight of the 10 resected kidneys was 1.95±0.15cm and 2.0±0.28g, respectively. The images were represented by three-dimensional arrays of cubic voxels with opacities in the blood vessels. In the section taken from the arrays, four regions of the kidney could be identified easily by their characteristic vascular features. Conclusions: Micro-CT is a promising method for evaluating the renal microvascular architecture in a rat kidney. It can for the foundation of an experimental study aimed at providing quantitative information on the urinary system in a rodent model. Purpose: Rodent models that mimic human renal diseases are being increasingly recognized as powerful tools in the development of new drugs and for evaluating the efficacy of novel therapeutics in a preclinical setting. However, there are few reports on microvasculature imaging of the urinary system in small animals. An experimental study was performed to evaluate the microvasculature in a rat kidney using micro- computed tomography(CT) with three-dimensional images. Materials and Methods: Five Sprague-Dawley male rats(age: 10-12 weeks, weight: 200-250g) underwent a laparotomy under anesthesia with an intramuscular injection of 0.5cc xylazine hydrochloride and ketamine mixed solution(1:10). After ligation of the abdominal aorta and inferior vena cava immediately above the renal artery, a 24 gazed catheter was inserted into the abdominal aorta. A physiological solution and heparin(500U) were infused through the catheter to flush the blood from the renal vasculature. The kidney was enhanced using self-made contrast material. The excised kidney was frozen for the micro-CT scan. Results: The mean longitudinal diameter and weight of the 10 resected kidneys was 1.95±0.15cm and 2.0±0.28g, respectively. The images were represented by three-dimensional arrays of cubic voxels with opacities in the blood vessels. In the section taken from the arrays, four regions of the kidney could be identified easily by their characteristic vascular features. Conclusions: Micro-CT is a promising method for evaluating the renal microvascular architecture in a rat kidney. It can for the foundation of an experimental study aimed at providing quantitative information on the urinary system in a rodent model.

      • SCOPUSKCI등재
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