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A Study of Gamma-ray Distribution around the $^{99}Mo-^{99m}TcO_4$ Generator ($^{99}Mo-^{99m}TcO_4$ Generator의 감마선량 분포에 관한 연구)

  • Park, Soung-Ock
    • Journal of radiological science and technology
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    • v.24 no.1
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    • pp.49-53
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    • 2001
  • A number of radionuclides of interest in nuclear medicine are short lived isotopes that emit only gamma ray. The most of all Dept. of Nuclear Medicine in the hospt. are using the $^{99}Mo-^{99m}Tc$ generator for elution of the short lived isotope $^{99m}TcO_4$. A $^{99}Mo-^{99m}Tc$ generator consists of an alumina column on which $^{99}Mo$ is bound. The parent isotope($^{99}Mo$ : half life 67 hr.) decays to its daughter $^{99m}TcO_4^-$ which is a different element with a shorter half-life. $^{99}Mo$ emitted 41-keV(1.3%), 141-keV(5.6%) 181-keV(6.6%) and 366-keV(1.5%) gamma rays. But $^{99m}TcO_4$ emitted only 140-keV gamma ray. We study about the gamma ray distribution around the $^{99}Mo$ generator. And obtained the result as follows ; 1. Total counted gamma ray from generator smaller in front side than back. 2. The gamma ray emitted from $^{99}Mo$ generator without $^{99m}TcO_4$ vial increased in the back side(Mo column posited side) 3. The gamma ray only from the $^{99m}TcO_4$ vial increased in the front side. 4. Apron can protect gamma ray above 60% of total radiation from the $^{99}Mo$ generator.

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Effect of the Structure of MoO3/bismuth molybdate Binary Phase Catalysts on the Selective Oxidation of Propylene (MoO3/bismuth molybdate 혼합 2상 촉매의 구조에 따른 프로필렌 선택산화반응 특성)

  • Cha, T.B.;Choi, M.J.;Park, D.W.;Chung, J.S.
    • Applied Chemistry for Engineering
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    • v.3 no.1
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    • pp.53-63
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    • 1992
  • M/BM -series catalysts, $MoO_3$ supported on ${\alpha}-Bi_2Mo_3O_{12}$ were also prepared by impregnation method. BM/M-series catalysts, ${\alpha}-Bi_2Mo_3O_{12}$ supported on $MoO_3$ were also prepared by coprecipitation. Structure and catalytic properties of the two phase catalysts were studied by means of using nitrogen adsorption, X-ray diffraction, and scanning electron microscopy. The reaction test for the selective oxidation of propylene to acrolein over Bi-molybdate catalysts was studied using a fixed-bed reactor system. In M/BM-series catalysts, $MoO_3$ was dispersed on ${\alpha}-Bi_2Mo_3O_{12}$, and the crystal structure of ${\alpha}-Bi_2Mo_3O_{12}$ remains unchanged by the presence of excess $MoO_3$. However the surface morphology and bulk structure of BM/M-series catalysts were altered probably because the precipitated $Bi(OH)_3$ reacted with $MoO_3$ during the calcination to form ${\alpha}-Bi_2Mo_3O_{12}$ phase. The results of propylene oxidation on both series catalysts showed that the reaction took place over the surface of ${\alpha}-Bi_2Mo_3O_{12}$ particle and the role of excess $MoO_3$ was to supply oxygen to ${\alpha}-Bi_2Mo_3O_{12}$. These increasing effects on activity were also observed in the mechanical mixtures of ${\alpha}-Bi_2Mo_3O_{12}$ and $MoO_3$.

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Synthesis and Characterization of Molybdenum and Tungsten Oxo-Nitrosyl Complexes Containing ${Mo(NO)_2}^{2+}$ Unit with Isobutyl- and n-Butylamidoxime (이소부틸과 부틸아미드옥심으로한 ${Mo(NO)_2}^{2+}$ 단위체가 포함하는 몰리브덴과 텅스텐 산소-니트로실 착물의 합성과 성질)

  • Roh, Soo Gyun;Oh, Sang Oh
    • Journal of the Korean Chemical Society
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    • v.39 no.5
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    • pp.393-398
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    • 1995
  • The oxo-nitrosyl complexes (n-Bu4N)2[M4O12Mo(NO)2{RC(NH2)NHO}2{RC(NH)NO}2] (M=Mo, W; R=(CH3)2CH, n-CH3CH2CH2) have been prepared by the reactions of monomeric complex containing {Mo(NO)2}2+ and polyoxometalates with isobutyl- and n-butylamidoxime. The prepared complexes were characterized by elemental analysis, infrared, 1H NMR, 13C NMR and UV-visible spectroscopy. These complexes contain two {M2O5}2+ [M=Mo, W] cores and a central {Mo(NO)2}2+ core. The {Mo(NO)2}2+ unit was the formally cis type and C2v symmetry in geometric structure. The two {M2O5}2+ cores and a central {Mo(NO)2}2+ core were not nearly interacted with electronic localization, which were identified by spectroscopy.

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Relationship of Compressed Breast Thickness and Average Glandular Dose According to Focus/Filter (초점/필터에 따른 유방 압박 두께와 평균 유선 선량의 관계)

  • Lee, In-Ja
    • Journal of radiological science and technology
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    • v.32 no.3
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    • pp.261-270
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    • 2009
  • The study examined the relationship between the compressed breast thickness and Average Glandular Dose (AGD) among 1,969 outpatients who went through breast X-ray in a university hospital for 10 months from July 1st, 2007 to April 30th, 2008. Then it analyzed the result acquired from 3,900 cases of Cranio-Caudal (CC) view, especially, when the breasts were compressed (13-15daN). The following is the conclusion driven from the relationship analysis. 1. The subjects aged in 40s and 50s were 2,679 out of 3,900 cases and this figure was 68.69% in all. 2. In terms of distribution depending on focus/filter, 41.0% was Mo/Mo, 34.8% was Mo/Rh, and 24.2% was Rh/Rh. 3. In terms of compressed breast thickness depending on focus/filter, the average thickness was 26.91 mm at Mo/Mo, 38.84 mm at Mo/Rh, and 48.80 mm at Rh/Rh. The average thickness of the entire cases was shown to be 36.27 mm. 4. AGD depending on focus/filter was 1.27 mGy at Mo/Mo, 1.55 mGy at Mo/Rh, and 1.42 mGy at Rh/Rh. The average glandular dose of the entire cases was shown to be 1.43 mGy. 5. The relationship of AGD depending on compressed breast thickness at Mo/Mo was y=0.0318x + 0.470 while it was y=0.0206x + 0.709 at Mo/Rh and y=0.0248x + 0.335 at Mo/Rh. It was highly influenced by the compressed breast thickness, however, more variation was detected at Mo/Mo depending on breast thickness.

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Characterization of Toxicity Symptoms of Molybden and Determination of Tissue Threshold Levels for Diagnostic Criteria in Korean Bred Strawberries (국내육성 주요 딸기 품종에서 발생하는 Mo 과잉 증상 및 영양진단을 위한 식물체 내 한계농도)

  • Choi, Jong-Myung;Nam, Min-Ho;Lee, Chi-Won W.;Chun, Jong-Pil
    • Horticultural Science & Technology
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    • v.30 no.4
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    • pp.392-399
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    • 2012
  • This study was carried out to investigate the influence of molybden (Mo) concentrations in fertilizer solution on the growth of and nutrient uptake by domestically bred strawberries. Tissue analysis based on the dry weight was also conducted to determine the threshold levels in plants when Mo toxicity developed in strawberries. The leaf chlorophyll contents decreased lineally as Mo concentrations in the fertilizer solution were elevated. The differences among treatments in chlorophyll contents were statistically significant. The fresh and dry weights decreased significantly when the Mo concentrations in fertilizer solution were higher than 3.0 mM in 'Keumhyang' and 'Maehyang' strawberries and 1.0 mM in 'Seolhyang' strawberry. The elevation of Mo concentrations in fertilizer solution resulted in severe toxicity and crops developed the unique symptoms. The margin of older leaves became yellow and desiccated. Then, the margin of leaf blade rapidly became bronze colored and died as the symptoms spread up the plants. The interveinal area of the young leaves became yellowing. The elevation of Mo concentrations in fertilizer solution did not influence the tissue P, K, and Mg contents based on the dry weight. The tissue Ca contents were higher in 1.0 mM treatment than other treatments of 'Keumhyang' and 'Seolhyang' strawberries. The tissue Mo contents based on the dry weight of 'Keumhyang', 'Maehyang', and 'Seolyahng' strawberries were 76.5, 104.0, and 187.3 $mg{\cdot}kg^{-1}$, respectively, in the 0.25 mM treatments and 4,155, 5,367, and 2,190 $mg{\cdot}kg^{-1}$, respectively, in the 4.0 mM treatments. The contents increased lineally as Mo concentrations in fertilizer solution were elevated. When the concentration of Mo at which growth of crops were retarded by 10% is regarded as threshold level, the Mo contents based on dry weight of above ground plant tissue should be lower than 653.4, 686.2, and 589.7 $mg{\cdot}kg^{-1}$, in 'Keumhyang', 'Maehyang', and 'Seolyahng' strawberries, respectively.

A Study of Mo Back Electrode for CIGSe2 Thin Film Solar Cell (CIGSe2 박막태양전지용 Mo 하부전극의 물리·전기적 특성 연구)

  • Choi, Seung-Hoon;Park, Joong-Jin;Yun, Jeong-Oh;Hong, Young-Ho;Kim, In-Soo
    • Journal of the Korean Vacuum Society
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    • v.21 no.3
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    • pp.142-150
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    • 2012
  • In this Study, Mo back electrode were deposited as the functions of various working pressure, deposition time and plasma per-treatment on sodalime glass (SLG) for application to CIGS thin film solar cell using by DC sputtering method, and were analyzed Mo change to $MoSe_2$ layer through selenization processes. And finally Mo back electrode characteristics were evaluated as application to CIGS device after Al/AZO/ZnO/CdS/CIGS/Mo/SLG fabrication. Mo films fabricated as a function of the working pressure from 1.3 to 4.9mTorr are that physical thickness changed to increase from 1.24 to 1.27 ${\mu}m$ and electrical characteristics of sheet resistance changed to increase from 0.195 to 0.242 ${\Omega}/sq$ as according to the higher working pressure. We could find out that Mo film have more dense in lower working pressure because positive Ar ions have higher energy in lower pressure when ions impact to Mo target, and have dominated (100) columnar structure without working pressure. Also Mo films fabricated as a function of the deposition time are that physical thickness changed to increase from 0.15 to 1.24 ${\mu}m$ and electrical characteristics of sheet resistance changed to decrease from 2.75 to 0.195 ${\Omega}/sq$ as according to the increasing of deposition time. This is reasonable because more thick metal film have better electrical characteristics. We investigated Mo change to $MoSe_2$ layer through selenization processes after Se/Mo/SLG fabrication as a function of the selenization time from 5 to 40 minutes. $MoSe_2$ thickness were changed to increase as according to the increasing of selenization time. We could find out that we have to control $MoSe_2$ thickness to get ohmic contact characteristics as controlling of proper selenization time. And we fabricated and evaluated CIGS thin film solar cell device as Al/AZO/ZnO/CdS/CIGS/Mo/SLG structures depend on Mo thickness 1.2 ${\mu}m$ and 0.6 ${\mu}m$. The efficiency of CIGS device with 0.6 ${\mu}m$ Mo thickness is batter as 9.46% because Na ion of SLG can move to CIGS layer more faster through thin Mo layer. The adhesion characteristics of Mo back electrode on SLG were improved better as plasma pre-treatment on SLG substrate before Mo deposition. And we could expect better efficiency of CIGS thin film solar cell as controlling of Mo thickness and $MoSe_2$ thickness depend on Na effect and selenization time.

Synthesis and Characterization of Nb, Mo-doped and Nb/Mo-codoped Monoclinic VO2 Nanoparticles and Their Thin Films by Hydrothermal/Post-Thermal Transformation and Wet-Coating Method

  • Kim, Jongmin;Jung, Young Hee;Kwak, Jun Young;Kim, Yeong Il
    • Journal of the Korean Chemical Society
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    • v.63 no.2
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    • pp.94-101
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    • 2019
  • Nb, Mo-doped and Nb/Mo-codoped $VO_2(M)$ nanocrystallites with various doping levels were synthesized for the first time by a hydrothermal and post thermal transformation method. The reversible phase transition characteristics of those doped $VO_2(M)$ was comparatively investigated. Nb-doping of $VO_2(M)$ by this method resulted in a very efficient lowering of the transition temperature ($T_c$) with a rate of $-16.7^{\circ}C/at.%$ that is comparable to W-doping, while Mo-doping did not give a serious reduction of $T_c$ with only a rate of $-5.1^{\circ}C/at.%$. Nb/Mo-codoping gave a similar result to Nb-doping without a noticeable difference. The thin films of Nb-doped and Nb/Mo-codoped $VO_2(M)$ with a thickness of ca. 120 nm were prepared by a wet-coating of the nanoparticle-dispersed solutions. Those films showed a good thermochromic modulation of near infrared radiation with 30-35% for Nb-doped $VO_2(M)$ and 37-40% for Nb/Mo-codoped ones. Nb/Mo-codoped $VO_2(M)$ film showed slightly enhanced thermochromic performance compared with Nb-doped $VO_2(M)$ film.

Magnetic Properties in Alternating Magnetic Field for the Sintered Ee-l7Cr-2M(M=Si, Nb, Mo) Alloys (Fe-l7Cr-2M(M=Si, Nb, Mo)합금 분말 소결체의 교류 자기 특성)

  • 김정곤;김택기;오용수
    • Journal of the Korean Magnetics Society
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    • v.10 no.6
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    • pp.269-273
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    • 2000
  • Fe-l7Cr-2M(M=Si, Nb, Mo) alloy powder was prepared by plasma electrode rotating atomizer and than the alloy powder was formed and sintered. The particle shape of the Fe-l7Cr-2M(M=Si, Nb, Mo) alloy power is spherical. The saturation magnetization of the sintered Fe-17Cr-2Mo and Fe-l7Cr-2Nb alloy are 155 emu/g. The saturation magnetization of the sintered Fe-l7Cr-2Si alloy is less than that of the sintered Fe-l7Cr-2Mo and Fe-l7Cr-2Nb alloy. The amplitude relative permeability of the sintered Fe-l7Cr-2M(M=Si, Nb, Mo) alloy has the maximum value in the range of 3∼5 Oe applied field at forming pressure 12 ton/cm$^2$, sintering temperature 1200$^{\circ}C$, and frequency 1 kHz. Power loss of the sintered Fe-l7Cr-2Nb alloy is 40 mW/cc at applied field, H$\sub$a/=5 Oe, and frequency, f=1 kHz. The power loss of the sintered Fe-l7Cr-2Nb alloy is a half of that of the sintered Fe-l7Cr-2Si and Fe-l7Cr-2Mo alloy.

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Heat Resistance Properties of Thin Section HiSiMo Ductile Iron for Exhaust Manifold (배기 매니폴드용 박육 고규소 구상흑연주철의 내열 특성)

  • Lee, Do-Kyung;Kim, Sung-Gyu;Lee, Byung-Woo
    • Journal of the Korea Society For Power System Engineering
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    • v.17 no.4
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    • pp.109-114
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    • 2013
  • In this study, the microstructure, mechanical properties and high temperature oxidation characteristics of HiSiMo and HiSiMoM ductile iron for exhaust manifold were investigated. The HiSiMoM ductile iron was developed by optimization of alloying element addition and casting design. The exhaust manifold prototype was fabricated using the HiSiMoM iron and this resulted in the weight saving of 0.73kg. The microstructures of the HiSiMo and HiSiMoM irons were similar each other and graphite nodularity was 89% and 93% respectively. Tensile strengths of them were 663.5 and 674.4 MPa and Brinell hardness were 235.3 and 243.9 respectively. Both irons showed parabolic weight gain behavior in high temperature oxidation atmosphere. Oxidation layer was divided into external and internal layers. The weight gain of the HiSiMoM iron was lower than that of the HiSiMo iron after isothermal oxidation test at $900^{\circ}C$. This should be rationalized by higher Si enrichment at the interface of the matrix and internal layer of the HiSiMoM iron.

Magnetic Properties of ${\alpha}-Fe$ Based Nd-Fe-B Melt-Spun Alloys (${\alpha}-Fe$ 기 Nd-Fe-B 급속응고합금의 자기특성)

  • 조용수;김윤배;박우식;김희태;김창석;김택기
    • Journal of the Korean Magnetics Society
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    • v.4 no.2
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    • pp.122-125
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    • 1994
  • The magnetic properties of Nd-Fe-B alloys of containing 4 at.% Nd have been studied for the development of new type rare-earth magnets. The amorphous phase of a melt-spun $Nd_{4}Fe_{85.5}B_{10.5}$ alloy is transformed into the phases which have a small amount of $Nd_{2}Fe_{14}B_{1}$ in ${\alpha}-Fe$ matrix by annealing above their crystallization temperature. The addition of Mo, Nb, V or Cu to $Nd_{4}Fe_{85.5}B_{10.5}$ alloy results in the reduction of grain size and the sub¬sequent improvement of the coercivity. The coercivity of $Nd_{4}Fe_{82}B_{10}M_{3}Cu_{1}$(M = Mo, Nb, V) alloys increases in the order of M = V < Nb < Mo and shows the highest value of 2.7 kOe when M = Mo. On the other hand, the rem¬anence of these alloys shows the opposite trend and the rn>st improved value of 1.35 T is observed when M = V.

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