• 한국세라믹학회지
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• 제30권7호
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• pp.563-570
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• 1993

Spherical, monosized gadolinium compound was prepared by the reaction of Gd(NO3)3 solution with decomposition products of urea in the solution at evaluated temperature. Chemical composition and calcination characteristics of spherical gadolinium compound prepared were investigated by X-ray IR and TG-DTA. The approximate chemical composition of the spherical particle precipitated was Gd(OH)CO3.1.5H2O. Gd(OH)CO3.1.5H2O was calcined to monoclinic type Gd2O3 at 115$0^{\circ}C$ via cubic type Gd2O3 near $600^{\circ}C$. The effects of various parameters such as pH, temperature, concentration ratio of urea to gadolinium precusor, ageing time, and others material (CCl3COOH and HOCNH2) in stead of urea as precipitating agent on the properties of the resulting precipitates were studied systematically.

• 한국세라믹학회지
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• 제47권2호
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• pp.177-182
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• 2010

To synthesize $Gd_2O_3:Eu^{3+}$ phosphor, gadolinium-europium oxalate precursors were prepared from oxalic acid, NaOH or aqueous ammonia via coprecipitation method. The obtained precursors were heat-treated and then characterized by XRD, SEM and PL. The kinds and amounts of coprecipitant (NaOH or aqueous ammonia) were found to affect the powder morphology and properties of gadolinium-europium oxalate precursors. Two crystalline precursors and one amorphous precursor were synthesized. The nanometer-sized amorphous gadolinium-europium oxalate precursor was first prepared using the oxalate coprecipitation technique. The calcined powders obtained from the amorphous precursor were nearly spherical in shape, and a narrow size distribution was obtained. The NaOH coprecipitant was more effective in the preparation of nanometer-sized spherical powders. A thermal decomposition process was conducted for the three kinds of precursors. The photoluminescence property was also measured as a function of europium content, and concentration quenching occurred for samples with europium concentrations of over 10 mol%.

• Ocean and Polar Research
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• 제43권3호
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• pp.165-178
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• 2021

Gadolinium (Gd), one of a rare earth element (REE), has been widely used worldwide since the 1980s, as a resource material for contrast agents injected into examiners of magnetic resonance imaging (MRI) test. The organic complexed form of Gd shows an extremely stable behavior in natural environment (water), so is known that the artificial Gd from medical uses is not removed from the waste water treatment plant (WWTP) and eventually introduced into the ocean through the estuary. Since the 1990s, some previous studies have often been conducted on Gd anomalies in natural water and their effects an artificial origin from land or metropolitan areas, but little research has been potential impacts on the ocean water. In this paper, we review and introduce recent studies related to Gd anomaly in natural water and related marine effects, and also propose the future research directions.

• 분석과학
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• 제20권2호
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• pp.131-137
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• 2007

이산화우라늄-이산화가돌리늄 핵연료를 질산으로 녹인 다음 우라늄 매트릭스로부터 가돌리늄을 분리하지 않고 유도결합플라스마 원자방출분광기(ICP-AES)로 바로 정량할 수 있는 분석조건을 검토하였다. 가돌리늄 분석에 미치는 우라늄의 분광학적 간섭 정도를 가돌리늄 스펙트럼으로부터 비교, 평가한 결과 336.223 nm의 파장이 분석선으로서 가장 적합하였다. 우라늄 매트릭스로부터 가돌리늄을 음이온 교환수지(Bio-Rad AG $1{\times}8$)로 분리한 다음 ICP-AES로 측정한 값과 바로 측정한 값을 견주어 본 결과, 상대편차는 5 % 범위 내에서 잘 일치하였다. 따라서 본 방법으로 핵연료($UO_2-Gd_2O_3$)에 함유되어 있는 5~10 wt.%의 가돌리늄을 분리 과정없이 바로 ICP-AES로 정량할 수 있었다.

• 한국환경성돌연변이발암원학회:학술대회논문집
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• 한국환경성돌연변이발암원학회 2002년도 Molecular and Cellular Response to Toxic Substances
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• pp.51-58
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• 2002

• 한국재료학회지
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• 제3권1호
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• pp.3-6
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• 1993

Gd박막의 강자성-상자성 상전이 온도(Tc)이동을 조사했다. 강자성-상자성 상전이 온도에서 전기저항이 변화되는 변곡점을 관측하여 Tc를 결졍하였는데, 두께가 6600$\AA$인 Gd박막의 상전이 온도는 bulk상태의 Gd의 전이온도보다 4$\pm$0.$3^{\circ}C$정도 아래로 이동됨을 알았다. 이것은 강자성 Gd박막의 Tc이동에 대한 최초의 측정이며, 실험과 finite-sime scaling이론을 비교 분석했다.

• 한국재료학회지
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• 제4권6호
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• pp.710-714
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• 1994

자화도를 측정함으로써 gadolinium박막의 강자성에서 상자성으로의 전이온도를 결정했다. 박막의 전이온도는 박막의 두께가 얇아짐에 따라 점점 더 bulk계의 전이온도보다 낮아지는 것이 관측되었으며 이 현상은 박막계의 유한성에 의해 일어나는 현상으로 알려져 있다. 우리는 이 결과를 유한효과 및 유한 축척이론에 근거하여 설명하였다.

• Investigative Magnetic Resonance Imaging
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• 제23권1호
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• pp.34-37
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• 2019

Gadolinium contrast agents (CAs) are integral components of clinical magnetic resonance imaging (MRI). However, safety concerns have arisen regarding the use of gadolinium CAs, due to their association with nephrogenic systemic fibrosis (NSF). Furthermore, recently the long-term retention of $Gd^{3+}-based$ CAs in brains patients with normal renal function raised another possible safety issue. The safety concerns of $Gd^{3+}-based$ CAs have been based on the ligand structure of $Gd^{3+}-based$ CAs, and findings that $Gd^{3+}-based$ CAs with linear ligand structures showed much higher incidences of NSF and brain retention of CAs than $Gd^{3+}-based$ CAs with macrocyclic ligand structure. In the current study, we report the in vivo biodistribution profile of a new highly stable multifunctional $Gd^{3+}-based$ CA, with macrocyclic ligand structure (HNP-2006). MR imaging using HNP-2006 demonstrated a significant contrast enhancement in many different organs. Furthermore, the contrast enhanced tumor imaging using HNP-2006 confirmed that this new macrocyclic CA can be used for detecting tumor in the central nervous system. Therefore, this new multifunctional HNP-2006 with macrocyclic ligand structure shows great promise for whole-body clinical application.

• Nuclear Engineering and Technology
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• 제55권3호
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• pp.1031-1035
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• 2023

Neutron is an indirectly ionizing particle without charge, which is normally measured by detecting reaction products. Neutron detection system based on measuring gadolinium-converted gamma-rays is a good way to monitor the neutron because the representative prompt gamma-rays of gadolinium have low energies (79, 89, 182, and 199 keV). Low energy gamma-rays and their high attenuation coefficient on materials allow the simple design of a detector easier to manufacture. Thus, we designed a cadmium zinc telluride detector to investigate feasibility of simultaneous detection of gamma-rays and neutrons by using the Monte-Carlo simulation, which was divided into two parts; first was gamma-detection part and second was gamma- and neutron-simultaneous detection part. Consequently, we confirmed that simultaneous detection of gamma-rays and neutrons could be feasible and valid, although further research is needed for adoption on real detection.

• Nuclear Engineering and Technology
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• 제23권3호
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• pp.352-362
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• 1991

가압 경수로의 노심 설계에 있어서 제한된 우라늄 자원의 효율적인 이용을 위한 다양한 방안으로 장주기 운전, 고연소도 및 저누출 장전 모형 통을 강구하고 있는 추세이다. 이러한 노심들은 원자로 운전 주기 전반에 걸친 공간적 출력 분포 제어와 잉여 반응도 제어를 위해 가연성 독물질을 사용하고 있다. 이와 관련하여 가연성 독물질 관리의 최적화 연구가 다각도로 진행되고 있다. 본 연구에서는 1990년도부터 국내 가압 경수로에 국산 핵연료가 장전되기 시작하면서 가도리니아 독봉을 사용하고 있으며 장차 주된 가연성 독물질로 쓰일 예정이므로 이에 대해서 분석을 수행하였다. 분석 결과 가도리니아 독봉은 열중성자 흡수 단면적이 매우 큰데서 기인한 특이한 연소 특성을 보이고 있다. 특히 집합체 내에서의 가도리니아 독봉의 위치에 따라 매우 다양한 출력 분포를 보이고 있다. 이러한 다양한 출력 분포 중에서 노심의 반경 방향 첨두 출력을 가능한 낮게하는 집합체 내에서의 가도리니아봉 위치 최적 선정을 위한 방법론을 제시하였다.