• Title/Summary/Keyword: Re(VII)

Search Result 12, Processing Time 0.023 seconds

Investigation of Sorption Reaction of Re(VII) onto HDPy- and HDTMA-modified Bentonite (HDPy 및 HDTMA로 개질된 벤토나이트에 대한 Re(VII)의 흡착반응 분석)

  • Jun-Myung Choi;Junhyuk Ha;Ranyeong Choi;Jun-Yeop Lee
    • Journal of Radiation Industry
    • /
    • v.18 no.3
    • /
    • pp.167-171
    • /
    • 2024
  • Technetium-99 (99Tc) is recognized as a critical concern in the disposal of spent nuclear fuel due to its long half-life and remarkable stability, existing predominantly as TcO4- in the natural environment. The anionic form of technetium is highly soluble and mobile, posing significant environmental risks from the viewpoint of nuclear waste management. Thus, developing efficient and cost-effective sorbents for aqueous Tc(VII) is essential for mitigating relevant contamination. In the present work, the adsorption characteristics of Re(VII), a chemical analog of Tc(VII), were investigated using the clay mineral bentonite, modified with two different organic cations: hexadecylpyridinium (HDPy) and hexadecyltrimethylammonium (HDTMA). Sorption experiments were conducted at a liquid-to-solid ratio of 1 g/L with Re(VII) solutions prepared at concentrations from 10-4 mol/L to 10-6 mol/L. The sorption ratio and distribution coefficients were determined with samples collected at reaction times of 10, 50, 100, and 500 minutes after 0.45 ㎛ syringe filtration. In parallel, the modified bentonite samples were further analyzed using the X-ray diffraction (XRD) method to understand the adsorption mechanism of Re(VII) onto the target minerals. According to the quantification analysis results, a rapid equilibrium reaction of aqueous Re(VII) for all modified bentonite samples was identified. Moreover, near-complete adsorption of Re(VII) was observed when the bentonite was modified at 200-400% of its cation exchange capacity (CEC) for both organic cations. For cases of lower modification, the HDTMA-modified bentonite showed relatively higher adsorption efficiency compared with the one modified with HDPy. This result was inferred to be due to the difference in inter-layer spacing based on the characteristics of the organic cations. It is expected that the results obtained through this study will serve as a preliminary case for the synthesis of adsorbents for the retardation of highly mobile anionic radionuclides, such as I and Tc, in the natural environment.

Ion Exchange Recovery of Rhenium and Its Determination in Aqueous Solutions by Diffuse Reflection Spectroscopy

  • Kalyakina, O.P.;Kononova, O.N.;Kachin, S.V.;Kholmogorov, A.G.
    • Bulletin of the Korean Chemical Society
    • /
    • v.25 no.1
    • /
    • pp.79-84
    • /
    • 2004
  • The existing technological schemes for processing rhenium-containing raw materials involve the recovery of Re from solutions, which can be effectively achieved by anion exchange method. The application of anion exchange also allows to study rhenium state in aqueous solutions and to develop analytical control methods. The present work is focused on investigation of ion exchange equilibrium in the analytical system Re(VII)-HCl-$SnCl_2$-KSCN-anion exchanger by means of sorption-desorption method as well as by electron, IR- and diffuse reflection spectroscopy. It was shown that rhenium can be quantitatively recovered from this system. It is proposed to use the sorption-spectroscopic method for Re(VII) determination in aqueous solutions. The calibration curve is linear in the concentration range of 0.5-20.0 mg/L (sample volume is 25.0 mL) and the detection limit is 0.05 mg/L. The presence of Mo(VI), Cu(II), Fe(II, III), Ni(II), Zn(II) as well as $K^+,\;Na^+$ do not hinder the solid-phase determination of rhenium. Rhenium (VII) determination by diffuse reflection spectroscopy was carried out in model solutions as well as in samples of river-derived water and in solutions obtained after the dissolution of spent catalysts.

Study on Tooth Micro-geometry Optimization of Rear Gear Set in 2 Speed Planetary Gear Reducer (2단 유성기어 감속기의 후부기어 치형수정에 관한 연구)

  • Jeon, Min-Hyung;Kim, Lae-Sung;Noh, Seung-Yoon;Zhen, Qin;Choi, Chang;Lyu, Sung-Ki
    • Journal of the Korean Society of Manufacturing Process Engineers
    • /
    • v.16 no.5
    • /
    • pp.1-6
    • /
    • 2017
  • Gear tooth micro-geometry modifications include the intentional removal of material from the gear teeth flanks, so that the shape is no longer a perfect involute. If the gear shapes are perfect, then the gear tooth meshing is better, therefore the gears will transmit input torque in a more efficient manner without the generation of high frequency engine fluctuation noise. In this paper, we study tooth micro-geometry optimization of rear gear set in 2 speed planetary gear reducers. Analysis revealed problems which are need of modification. Based on the results, tooth micro-geometry was used to deal with load distributions on the rear gear set.

The Microstructures and Hot Extrudability of Semi-solid AM100A Magnesium Alloy Fabricated by Cooling Plate (냉각판으로 제조한 반응고 AM100A 마그네슘 합금의 미세조직 및 열간 압출성)

  • Kim, Dae-Hwan;Sung, Young-Rock;Shim, Sung-Yong;Lee, Sang-Yong;Kim, Kwang-Sam;Lim, Su-Gun
    • Journal of Korea Foundry Society
    • /
    • v.29 no.3
    • /
    • pp.144-149
    • /
    • 2009
  • In this study, we investigated optimum condition of cooling plate method to obtain semi-solid AM100A Mg alloy with fine and globular morphology. AM100A Mg alloy were hot extruded at $380^{\circ}C$ extrusion temperature under extrusion ratio of 25 : 1 and ram speed of 2.4 mm/sec. Vickers hardness test, optical microscopy, scanning electron microscopy, and image analyzer were performed to identify the optimum conditions of cooling plate method. Optimum conditions of cooling plate method to fabricate semi-solid AM100A Mg alloy with fine and globular microstructures were achieved at a pouring temperature of $602^{\circ}C$ and the angle of cooling plate of 60 degree.

Isolation of the Anti-tumor Promoters from Citrus Peels (감귤과피로부터 발암 promotion 억제활성성분의 분리)

  • Yoon, Chang-Hoon;Jwa, Seung-Mi
    • Applied Biological Chemistry
    • /
    • v.49 no.1
    • /
    • pp.25-29
    • /
    • 2006
  • This study was carried out to isolate the possible anti-tumor promoters from the citrus peel (Citrus natsudaidai Hayata). We fractionated the cold-pressed oil of citrus peel by column chromatography, HPLC and TLC. The analysis on column chromate-graphy yielded seven peaks $(F-I{\sim}F-VII)$, all of which showed single spot on TLC analysis ($R_f$ for $F-I{\sim}VIII$; 0.31, 0.13, 0.13, 0.78, 0.79, 0.69 and 0.84). Among the seven fractions, three fractions (F-I, -II and F-IV) were re-analyzed on HPLC, also showing single peak except for one fraction (F-IV) which was divided two peaks. The retention times $(R_f)$ of F-I and F-II was 3 min. and 2.5 min., respectively, but these of two peaks from F-IV were 2 min. and 4.5 min., respectively. Since the area of the latter peak (4.5 min.) was very smaller than that of the former one (2 min.), it is considered that the latter one did not appear on TLC analysis. The inhibitory effect on tumor promoter 12-O-tetradecanoylphorbol-13-acetate(TPA)-induced Epstein-Barr virus activation in Raji cells was tested for the seven fraction obtained. It decreased in order of F-VI (82.3+1.3%) > F-I (80.4+1.6%) > F-II (77.2+0.9%) > F-III (75.0+1.2%) > F-IV (74.1=1.0%) > F-V (71.0+1.1%) > F-VII (70.2+1.2%). These results imply that some constiuents contained in citrus peels have the inhibitory activity of TPA-induced tumor promotion.

The Lost Das Ding and A Posthumous Subject of Lacan's Psychoanalysis - Mugunghwa Flowers Do Not Bloom - (잃어버린 das Ding과 라캉 정신분석의 사후 주체 - 무궁화 꽃은 피지 않는다 -)

  • Lee, Dong Seok
    • The Journal of the Convergence on Culture Technology
    • /
    • v.8 no.5
    • /
    • pp.127-136
    • /
    • 2022
  • This thesis is a study of "Ethics Seminar VII of Psychoanalysis" that Jacques Lacan (1901~1981) has the most attachment to.A translated version has not yet been released in Korea. The original French and English translations of Lacan Seminar VII were used for the study version. Lacan introduces an important concept in a seminar on the ethics of psychoanalysis. In German, it is 'das Ding'. It is translated as 'big thing' in Korean. Lacan introduces the term in French as 'La Chose'. In English, it is The Thing. "Big things" are also things that my mother gave me when I was young. It can also be interpreted as a loss of childhood that is not completely resolved. Therefore, Lacan' subject refers to develops a lifelong journey to recover the lost object. Lacan presents this point as the starting point of the psychoanalytic ethics. We try to re-examine the issue of ethics by tracing 'das Ding' as a lost place in the main article. First, We will look at the origins of das Ding. Second, through the relationship between love and das Ding, We will discuss who tries to fill Ding's void. Third, We will try to interpret the relationship between American ego psychology and das Ding in Lacan's scheme. Lastly, a posthumous subject will be dealt with through the play 'Mugunghwa has bloomed.'

Characteristic on the Heating Deformation of Sleeve by Heating Method (열처리공법에 따른 Sleeve의 열처리 변형 특성)

  • Youn, Il-Joong;Lyu, Sung-Ki;An, Chang-Woo;Ahn, In-Hyo
    • Journal of the Korean Society of Safety
    • /
    • v.21 no.3 s.75
    • /
    • pp.1-7
    • /
    • 2006
  • Nowadays, out of other transmission parts, the sleeve is getting more and more important part for exact and smooth shifting from gear ratio change whenever drivers are needed. To exact and smooth shifting when drivers are needed, all the parts connected with gear shifting should be machined exactly and having dimensions designers are intended. Especially, in case of the sleeve that the most important functional part to shift from gear ratio change that drivers are intended, it needs high precision grade and quality in both sides runout and outer dia runout as well as inner spline small dia & large dia. Because it's assembled with the synchro hub spline and shifted directly with the mating cone. So, it should be applied the hear treatment(hereinafter referred to H.T.M.T) to prevent the friction and percussion loss from shifting with mating cone. At this time, the deformation problems are raised from almost H.T.M.T. process and it makes the inferior part.

Linear Analysis of Geared System with a Manual Transmission (수동 변속기 내 기어 선형해석을 통한 동역학적 해석)

  • Ahn, Min-Ju;Cho, Sung-Min;Yoon, Jong-Yun;Kim, Jun-Seong;Lyu, Sung-Ki
    • Journal of the Korean Society of Safety
    • /
    • v.22 no.5
    • /
    • pp.1-6
    • /
    • 2007
  • Vibro-impacts in manual transmissions result due to several nonlinearities such as multi-staged clutch characteristics and gear backlashes. For the sake of understanding the torsional system, one specific manual transmission with front engine and front wheel drive configuration is investigated with a linear model under the several assumptions substituting the nonlinear factors. First, this system is examined with the mathematical approaches by expressing the governing equations to find out the torsional motions. Second, this system is analyzed using the linear model in order to understand its modal and frequency response characteristics using eigensolution method and the FRF(Frequency Responses Function) analysis. Third, with the given results from the eigensolutions, several mode shapes are investigated related to the torsional motion characteristics. Fourth, the system characteristics with the FRFs are studied with the basic approach, with which the several key parameters will be suggested based upon the results in the further studies.

Study on Simulation and Calculation Method of Thermal Error Compensation System for a Ball Screw Feed Drive (볼 스크류 이송장치 열 에러 보상 시스템의 시뮬레이션 및 계산 방법에 관한 연구)

  • Xu, Zhe Zhu;Choi, Chang;Kim, Lae-Sung;Baek, Kwon-In;Lyu, Sung-ki
    • Journal of the Korean Society of Manufacturing Process Engineers
    • /
    • v.16 no.2
    • /
    • pp.88-93
    • /
    • 2017
  • Due to the requirement of the development of the precision manufacturing industry, the accuracy of machine tools has become a key issue in this field. A critical factor that affects the accuracy of machine tools is the feed system, which is generally driven by a ball screw. Basically, to improve the performance of the feed drive system, which will be thermally extended lengthwise by continuous usage, a thermal error compensation system that is highly dependent on the feedback temperature or positioning data is employed in the machine tool system. Due to the overdependence on measuring technology, the cost of the compensation system and low productivity level are inevitable problems in the machine tool industry. This paper presents a novel feed drive thermal error compensation system method that could compensate for thermal error without positioning or temperature feedback. Regarding this thermal error compensation system, the heat generation of components, principal of compensation, thermal model, mathematic model, and calculation method are discussed. As a result, the test data confirm the correctness of the developed feed drive thermal error compensation system very well.

Fourteen new species of Allobathynella Morimoto and Miura, 1957 from South Korea: with a redescription of A. coreana Morimoto, 1970 (Crustacea, Bathynellacea, Parabathynellidae)

  • Park, Jong-Geun;Cho, Joo-Lae
    • Journal of Species Research
    • /
    • v.5 no.1
    • /
    • pp.49-156
    • /
    • 2016
  • Fourteen new species and A. coreana Morimoto, 1970 of Allobathynella Morimoto and Miura, 1957 are (re-)described and illustrated from the Korean Penninsula. Comparison of the external morphology of these species and two previously known species, A. japonica Morimoto and Miura, 1957 and A. shinjongieei Park and Cho, 2008 enables us to amend the generic diagnosis. A 7-segmented antennule turns out to be inconsistent character due to A. wonjuensis sp. nov., which has a 6-segmented antennule. On the other hand, the exopodal distal segment of thoracopods I-VII with a tiny terminal knob and with outer seta covered by long and strong barbs is proved to be a autapomorphic character of the genus. The 14 new species belong to the mirabilis-group and display more or less similar morphology. However, they differ from A. coreana, A. japonica and A. shinjongieei and from each other not only in quantitative but also in qualitative characters. These differences are summarized in tables. The species inhabit hyporheic zones of rivers and each appears to be highly endemic to a given tributary, having a range limit less than 100 km.