This study focused on evaluating the suitability of the WRK (waste repository Korea) bentonite as a buffer material in the SNF (spent nuclear fuel) repository. The U (uranium) adsorption/desorption ...characteristics and the adsorption mechanisms of the WRK bentonite were presented through various analyses, adsorption/desorption experiments, and kinetic adsorption modeling at various pH conditions. Mineralogical and structural analyses supported that the major mineral of the WRK bentonite is the Ca-montmorillonite having the great possibility for the U adsorption. From results of the U adsorption/desorption experiments (intial U concentration: 1 mg/L) for the WRK bentonite, despite the low ratio of the WRK bentonite/U (2 g/L), high U adsorption efficiency (>74%) and low U desorption rate (<14%) were acquired at pH 5, 6, 10, and 11 in solution, supporting that the WRK bentonite can be used as the buffer material preventing the U migration in the SNF repository. Relatively low U adsorption efficiency (<45%) for the WRK bentonite was acquired at pH 3 and 7 because the U exists as various species in solution depending on pH and thus its U adsorption mechanisms are different due to the U speciation. Based on experimental results and previous studies, the main U adsorption mechanisms of the WRK bentonite were understood in viewpoint of the chemical adsorption. At the acid conditions (＜pH 3), the U is apt to adsorb as forms of UO22+, mainly due to the ionic bond with Si-O or Al-O(OH) present on the WRK bentonite rather than the ion exchange with Ca2+ among layers of the WRK bentonite, showing the relatively low U adsorption efficiency. At the alkaline conditions (>pH 7), the U could be adsorbed in the form of anionic U-hydroxy complexes (UO2(OH)3-, UO2(OH)42-, (UO2)3(OH)7-, etc.), mainly by bonding with oxygen (O-) from Si-O or Al-O(OH) on the WRK bentonite or by co-precipitation in the form of hydroxide, showing the high U adsorption. At pH 7, the relatively low U adsorption efficiency (42%) was acquired in this study and it was due to the existence of the U-carbonates in solution, having relatively high solubility than other U species. The U adsorption efficiency of the WRK bentonite can be increased by maintaining a neutral or highly alkaline condition because of the formation of U-hydroxyl complexes rather than the uranyl ion (UO22+) in solution,and by restraining the formation of U-carbonate complexes in solution. 사용후핵연료(Spent nuclear fuel; SNF) 심지층 처분장의 완충재 소재로서 WRK (waste repository Korea) 벤토나이트가 적합한 지를 평가하기 위하여, 대표적인 방사성 핵종인 U (uranium)에 대한 WRK 벤토나이트의 흡/탈착 특성과 흡착 기작을 규명하는 다양한 분석, 흡/탈착 실내 실험, 동역학 흡착 모델링을 다양한 pH 조건에서 수행하였다. 다양한 특성 분석 결과, 주성분은 Ca-몬모릴로나이트이며, U 흡착 능력이 뛰어난 광물학적·구조적 특징들을 가지고 있었다. WRK 벤토나이트의 U 흡착 효율 및 탈착율을 규명하기 위한 흡/탈착 실험 결과, pH 5, 6, 10, 11 조건에서 WRK 벤토나이트와 U 오염수(1 mg/L)가 낮은 비율(2 g/L)로 혼합되었음에도 불구하고 높은 U 흡착 효율(>74%)과 낮은 U 탈착율(<14%)을 보였으며, 이는 WRK 벤토나이트가 SNF 처분장에서 U 거동을 제한하는 완충재 소재로서 적절하게 사용될 수 있음을 의미한다. pH 3과 7 조건에서는 상대적으로 낮은 U 흡착 효율(<45%)이 나타났으며, 이는 U가 용액의 pH 조건에 따라 다양한 형태로 존재하며, 존재 형태에 따라 상이한 U 흡착 기작을 가지기 때문으로 판단된다. 본 연구 실험 결과와 선행연구를 바탕으로 WRK 벤토나이트의 주요 화학적 U 흡착 기작을 pH 범위에 따라 용액 내 U의 존재 형태에 근거하여 설명하였다. pH 3 이하에서 주로 UO22+ 형태로 존재하는 U는 벤토나이트 표면의 Si-O 또는 Al-O(OH)와의 정전기적 인력(예: 이온 결합)에 의해 흡착되기 때문에 pH가 감소할수록 음전하 표면이 약해지는 WRK 벤토나이트 특성에 의해 비교적 낮은 U 흡착 효율이 나타났다. pH 7 이상의 알칼리성 조건에서 U는 음이온 U-수산화 복합체(UO2(OH)3-, UO2(OH)42-, (UO2)3(OH)7- 등)로 존재하며 비교적 높은 흡착 효율이 나타내는데, 이들은 벤토나이트에 포함된 Si-O 또는 Al-O(OH)의 산소원자를 공유하거나 리간드 교환에 의해 새로운 U-복합체가 형성되어 흡착되거나 수산화물 형태의 공침(co-precipitation)에 의해 벤토나이트에 고정되기 때문이다. pH 7의 중성 조건에서는 pH 5와 6보다 오히려 낮은 U 흡착 효율(42%)이 나타났는데, 이러한 결과는 용액 내 존재하는 탄산염(carbonate)에 의해 U가 U-수산화 복합체보다 용해도가 높은 U-탄산염 복합체로 존재하는 경우 가능하다. 연구 결과 pH를 약산성 또는 염기성 조건으로 유지하거나 용액 내 존재하는 탄산염을 제한함으로써 WRK 벤토나이트의 U 흡착 효율을 높일 수 있는 것으로 나타났다.
Covalent labeling of amino acids in proteins by reactive small molecules, in particular at cysteine SH and lysine NH groups, is a powerful approach to identify and characterize proteins and their ...functions. However, for the less-reactive carboxylic acids present in Asp and Glu, hardly any methodology is available. Employing the lipoprotein binding chaperone PDE6δ as an example, we demonstrate that incorporation of isoxazolium salts that resemble the structure and reactivity of Woodward's reagent K into protein ligands provides a novel method for selective covalent targeting of binding site carboxylic acids in whole proteomes. Covalent adduct formation occurs via rapid formation of enol esters and the covalent bond is stable even in the presence of strong nucleophiles. This new method promises to open up hitherto unexplored opportunities for chemical biology research.
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•Chemical probes based on Woodward's reagent K (WRK) are reactive, covalent inhibitors•WRK-derived probes selectively target glutamic acids in binding pockets•Covalent binding occurs with high selectivity in cell lysate•Inhibition of PDE6δ with WRK-derived probes overcomes Arl2-mediated inhibitor release
Martín-Gago et al. have developed a novel class of covalent probes based on Woodward's reagent K that allows selective covalent labeling of glutamic acid residues inside protein binding pockets.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
A tale of four kernels Spinellis, Diomidis
2008 ACM/IEEE 30th International Conference on Software Engineering,
01/2008, Volume:
2008, Issue:
24
Conference Proceeding, Journal Article
The FreeBSD, GNU/Linux, Solaris, and Windows operating systems have kernels that provide comparable facilities. Interestingly, their code bases share almost no common parts, while their development ...processes vary dramatically. We analyze the source code of the four systems by collecting metrics in the areas of file organization, code structure, code style, the use of the C preprocessor, and data organization. The aggregate results indicate that across various areas and many different metrics, four systems developed using wildly different processes score comparably. This allows us to posit that the structure and internal quality attributes of a working, non-trivial software artifact will represent first and foremost the engineering requirements of its construction, with the influence of process being marginal, if any.
The bentonite buffer material is a crucial component in an engineered barrier system used for the disposal of high-level radioactive waste. Because a large amount of heat from the disposal canister ...is released into the bentonite buffer material, the thermal conductivity of the bentonite buffer is a crucial parameter that determines the design temperature. At the Korea Atomic Energy Research Institute (KAERI), a new standard bentonite (Bentonil-WRK) has been used since 2022 because Gyeongju (KJ) bentonite is no longer produced. However, the currently available data are insufficient, making it essential to investigate both the basic and complex properties of Bentonil-WRK. Thus, this study evaluated its geotechnical and thermal properties and developed a thermal conductivity empirical model that considers its dry density, water content, and temperature variations from room temperature to 90°C. The coefficient of determination (R2) for the model was found to be 0.986. The thermal conductivity values of Bentonil-WRK were 1–10% lower than those of KJ bentonite and 10–40% higher than those of MX-80 bentonites, which were attributable to mineral-composition differences. The thermal conductivity of Bentonil-WRK ranged between 0.504 and 1.149 W·(m−1·K−1), while the specific heat capacity varied from 0.826 to 1.138 (kJ·(kg−1·K−1)).
Thermodynamic sorption modeling can enhance confidence in assessing and demonstrating the radionuclide sorption phenomena onto various mineral adsorbents. In this work, Ca-montmorillonite was ...successfully purified from Bentonil-WRK bentonite by performing the sequential physical and chemical treatments, and its geochemical properties were characterized using X-ray diffraction, Brunauer-Emmett-Teller analysis, cesium-saturation method, and controlled continuous acidbase titration. Further, batch experiments were conducted to evaluate the adsorption properties of Cs(I) and Sr(II) onto the homoionic Ca-montmorillonite under ambient conditions, and the diffuse double layer model-based inverse analysis of sorption data was performed to establish the relevant surface reaction models and obtain corresponding thermodynamic constants. Two types of surface reactions were identified as responsible for the sorption of Cs(I) and Sr(II) onto Ca-montmorillonite: cation exchange at interlayer site and complexation with edge silanol functionality. The thermodynamic sorption modeling provides acceptable representations of the experimental data, and the species distributions calculated using the resulting reaction constants accounts for the predominance of cation exchange mechanism of Cs(I) and Sr(II) under the ambient aqueous conditions. The surface complexation of cationic fission products with silanol group slightly facilitates their sorption at pH > 8.
A gene encoding a receptor-like protein kinase was isolated as the gene induced in the early period of N gene-dependent hypersensitive cell death in tobacco leaves. The kinase domain expressed as a ...glutathione S-transferase fusion protein was capable of autophosphorylation, indicating that this gene encodes an active protein kinase. A high level of the transcript accumulated before necrotic lesion formation in tobacco mosaic virus (TMV)-inoculated tobacco leaves carrying the N gene but it was low in a tobacco cultivar lacking the N gene. A small but reproducible increase in the transcript was found 1-2 h after a temperature shift from 30degC to 20degC even in healthy leaves, suggesting the gene expression is temperature sensitive. The gene was named WRK for wound-induced receptor-like protein kinase, because the transcript increased to a maximum within 15-30 min of wounding. In suspension cultured tobacco cells, an increase in the transcript was found 15 min after transfer to a new medium, but it was suppressed under high osmotic pressures. The wound-induced WRK accumulation was enhanced by cycloheximide treatment, but not by known defense signal compounds (salicylic acid, jasmonic acid, 1-aminocyclopropan-1-carboxylic acid and abscisic acid) and some plant hormones. Thus, WRK is a wound-inducible and temperature-sensitive protein kinase gene induced before hypersensitive cell death probably through unknown signaling pathways.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
This paper describes the Student Apprenticeship in Engineering, a programme which enables young people in full-time pre-16 education to undertake structured work-related learning at an approved ...training centre. Its aim is to provide students with the knowledge, skills and competences necessary to enter a career in the engineering sector and to give them the confidence to make informed choices regarding their chosen occupation and future employment.
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NUK, OILJ, SAZU, UKNU, UL, UM, UPUK
8.
Study of Handles Mechanism in WRK Chunxia Zhang; Xing Lin; Shuguang Lin ...
2010 Second International Conference on Information Technology and Computer Science,
2010-July
Conference Proceeding
This paper discusses handles, handle table, and the mechanism Window Research Kernel (WRK) applies to manage objects. In the kernel, Windows uses the concept of objects to facilitate managing ...resources and provides handles for applications to access kernel objects. So it is important for researchers and students to get a clear view of this mechanism. This paper describes structures of the handle and the handle table and the mapping-relationship between handles and kernel objects. Then it investigates how everyone can get the address of kernel objects manually by themselves and introduces two experiments to demonstrate this mapping-relationship.
Checkpoint is very important to system fault tolerance; the user space memory of specified process is saved as completely as possible in both kernel-level and user-level check pointing. While user ...space memory on Windows platform is divided into several blocks, which are possible in different states, but access state (i.e. committed state) is only one of them. This paper discusses the principle of user space memory management on Windows platform, and especially reveals the mechanism of region which includes virtual address continuous pages with same attributes. This paper presents the structure of user space virtual memory and the approaches to saving and recovery of user space virtual memory. The result is the same as expected.
Previous reports have suggested the existence of at least two pools of cellular myo-inositol (Ins); it has been further hypothesized that only one of these pools is utilized during hormone-activated, ...cyclic phosphatidylinositol (PtdIns) resynthesis. In an effort to investigate this possibility, we have undertaken kinetic studies of Ins metabolism in WRK-1 cells. Our results indicate that a single pool of Ins is involved in both basal and activated PtdIns synthesis. Ins generated by the hydrolysis of phosphatidylinositol 4,5-bisphosphate (PtdInsP2) mixes with the existing pool of free Ins and is not used exclusively for resynthesis of PtdIns.
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