Probing Quantum Confinement within Single Core–Multishell Nanowires

Martí,nez-Criado, Gema,Homs, Alejandro,Alé,n, Benito,Sans, Juan A.,Segura-Ruiz, Jaime,Molina-Sá,nchez, Alejandro,Susini, Jean,Yoo, Jinkyoung,Yi, Gyu-Chul American Chemical Society 2012 NANO LETTERS Vol.12 No.11

<P>Theoretically core–multishell nanowires under a cross-section of hexagonal geometry should exhibit peculiar confinement effects. Using a hard X-ray nanobeam, here we show experimental evidence for carrier localization phenomena at the hexagon corners by combining synchrotron excited optical luminescence with simultaneous X-ray fluorescence spectroscopy. Applied to single coaxial n-GaN/InGaN multiquantum-well/p-GaN nanowires, our experiment narrows the gap between optical microscopy and high-resolution X-ray imaging and calls for further studies on the underlying mechanisms of optoelectronic nanodevices.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/nalefd/2012/nalefd.2012.12.issue-11/nl303178u/production/images/medium/nl-2012-03178u_0007.gif'></P>

Dramatic Structural Rearrangements in Porous Coordination Networks

Martí,-Rujas, Javier,Islam, Nazrul,Hashizume, Daisuke,Izumi, Fujio,Fujita, Makoto,Kawano, Masaki American Chemical Society 2011 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.133 No.15

<P>With the use of <I>ab initio</I> X-ray powder diffraction, a family of isostructural crystalline porous coordination networks, [(ZnX<SUB>2</SUB>)<SUB>3</SUB>(TPT)<SUB>2</SUB>]<SUB><I>n</I></SUB>· (solvent) (X = I, Br, Cl), has been studied at elevated temperatures of 573−723 K. Upon heating, all three networks exhibited crystalline-to-amorphous-to-crystalline (CAC) phase transformations to three new networks, [(ZnI<SUB>2</SUB>)<SUB>3</SUB>(TPT)<SUB>2</SUB>]<SUB><I>n</I></SUB>, [(ZnBr<SUB>2</SUB>)<SUB>3</SUB>(TPT)<SUB>2</SUB>]<SUB><I>n</I></SUB>·(H<SUB>2</SUB>O) and [(ZnBr<SUB>2</SUB>)(μ-Br)(ZnBr)(TPT)]<SUB><I>n</I></SUB>, and [(ZnCl<SUB>2</SUB>)(μ-Cl)(ZnCl)(TPT)]<SUB><I>n</I></SUB>, respectively. A set of control experiments was used to obtain detailed mechanistic aspects of the CAC transformations. We demonstrate how bonds are broken and formed in these significant molecular rearrangements and how the initial arrangement plays a crucial role in the formation of the new networks after the CAC transformations. The structural information in the amorphous phase is retained and passed from a metastable to a more stable crystal, thus, reinforcing the notion that coordination networks are flexible and chemically active.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jacsat/2011/jacsat.2011.133.issue-15/ja109160a/production/images/medium/ja-2010-09160a_0014.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ja109160a'>ACS Electronic Supporting Info</A></P>

Kinetic Products in Coordination Networks: Ab Initio X-ray Powder Diffraction Analysis

Martí,-Rujas, Javier,Kawano, Masaki American Chemical Society 2013 Accounts of chemical research Vol.46 No.2

<P>Porous coordination networks are materials that maintain their crystal structure as molecular “guests” enter and exit their pores. They are of great research interest with applications in areas such as catalysis, gas adsorption, proton conductivity, and drug release. As with zeolite preparation, the kinetic states in coordination network preparation play a crucial role in determining the final products. Controlling the kinetic state during self-assembly of coordination networks is a fundamental aspect of developing further functionalization of this class of materials. However, unlike for zeolites, there are few structural studies reporting the kinetic products made during self-assembly of coordination networks. Synthetic routes that produce the necessary selectivity are complex.</P><P>The structural knowledge obtained from X-ray crystallography has been crucial for developing rational strategies for design of organic–inorganic hybrid networks. However, despite the explosive progress in the solid-state study of coordination networks during the last 15 years, researchers still do not understand many chemical reaction processes because of the difficulties in growing single crystals suitable for X-ray diffraction: Fast precipitation can lead to kinetic (metastable) products, but in microcrystalline form, unsuitable for single crystal X-ray analysis. X-ray powder diffraction (XRPD) routinely is used to check phase purity, crystallinity, and to monitor the stability of frameworks upon guest removal/inclusion under various conditions, but rarely is used for structure elucidation. Recent advances in structure determination of microcrystalline solids from ab initio XRPD have allowed three-dimensional structure determination when single crystals are not available. Thus, ab initio XRPD structure determination is becoming a powerful method for structure determination of microcrystalline solids, including porous coordination networks. Because of the great interest across scientific disciplines in coordination networks, especially porous coordination networks, the ability to determine crystal structures when the crystals are not suitable for single crystal X-ray analysis is of paramount importance.</P><P>In this Account, we report the potential of kinetic control to synthesize new coordination networks and we describe ab initio XRPD structure determination to characterize these networks’ crystal structures. We describe our recent work on selective instant synthesis to yield kinetically controlled porous coordination networks. We demonstrate that instant synthesis can selectively produce metastable networks that are not possible to synthesize by conventional solution chemistry. Using kinetic products, we provide mechanistic insights into thermally induced (573–723 K) (i.e., annealing method) structural transformations in porous coordination networks as well as examples of guest exchange/inclusion reactions. Finally, we describe a memory effect that allows the transfer of structural information from kinetic precursor structures to thermally stable structures through amorphous intermediate phases.</P><P>We believe that ab initio XRPD structure determination will soon be used to investigate chemical processes that lead intrinsically to microcrystalline solids, which up to now have not been fully understood due to the unavailability of single crystals. For example, only recently have researchers used single-crystal X-ray diffraction to elucidate crystal-to-crystal chemical reactions taking place in the crystalline scaffold of coordination networks. The potential of ab initio X-ray powder diffraction analysis goes beyond single-crystal-to-single-crystal processes, potentially allowing members of this field to study intriguing in situ reactions, such as reactions within pores.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/achre4/2013/achre4.2013.46.iss

Assessment of the effect of biofilm on the ship hydrodynamic performance by performance prediction method

Farkas Andrea,Degiuli Nastia,Martić Ivana 대한조선학회 2021 International Journal of Naval Architecture and Oc Vol.13 No.1

Biofouling represents an important problem in the shipping industry since it causes the increase in surface roughness. The most of ships in the current world fleet do not have good coating condition which represents an important problem due to strict rules regarding ship energy efficiency. Therefore, the importance of the control and management of the hull and propeller fouling is highlighted by the International Maritime Organization and the maintenance schedule optimization became valuable energy saving measure. For adequate implementation of this measure, the accurate prediction of the effects of biofouling on the hydrodynamic characteristics is required. Although computational fluid dynamics approach, based on the modified wall function approach, has imposed itself as one of the most promising tools for this prediction, it requires significant computational time. However, during the maintenance schedule optimization, it is important to rapidly predict the effect of biofouling on the ship hydrodynamic performance. In this paper, the effect of biofilm on the ship hydrodynamic performance is studied using the proposed performance prediction method for three merchant ships. The applicability of this method in the assessment of the effect of biofilm on the ship hydrodynamic performance is demonstrated by comparison of the obtained results using the proposed performance prediction method and computational fluid dynamics approach. The comparison has shown that the highest relative deviation is lower than 4.2% for all propulsion characteristics, lower than 1.5% for propeller rotation rate and lower than 5.2% for delivered power. Thus, a practical tool for the estimation of the effect of biofouling with lower fouling severity on the ship hydrodynamic performance is developed.

스포츠를 통한 사회성과 도덕성 발달

Marty Ewing 한국코칭능력개발원 2000 코칭능력개발지 Vol.2 No.2

USE OF FLOW-THROUGH SYSTEMS TO STUDY ANAEROBIC MICROBIAL PROCESSES WITHIN COASTAL LAGOON SEDIMENT

MARTY, Danielle,CAUMETTE, Pierre,BERTRAND, Jean Claude 영남대학교 해양과학연구소 1997 Marine Nature Vol.5 No.1

ABSTRACTExperimental continuous flow-through systems were used to investigate the effect of continuous nutrient inputs into sediments collected from a brackish coastal lagoon. Mixed anoxic surface sediments were percolated (40 ml·h-¹) in reactors with selected substrates (sucrose, acetate or trimethylamine) that enter the anaerobic food chain at different levels. After two months of continuous flow conditions, the number and activity of fermentative, denitrifying, sulfate-reducing and methanogenic bacteria were determined. Sulfate-reduction was the dominant terminal process in natural sediment and remained so in the different reactors, exhibiting rates one to three and one to two orders of magnitude greater than denitrification and methanogenesis rates, respectively. Sulfate-reduction was limited by electron donor availability in natural sediment. Continuous supply of sucrose allowed Sulfate-reduction as high as observed when acetate was a suitable energy source for sulfate-reducers. Denitrification was markedly limited by the low availability of nitrate. Methane production was essentially derived from trimethylamine, whereas acetate and hydrogen were primarily metabolized by sulfate-reducers. Maximal Sulfate-reduction resulted in methane production and denitrification markedly reduced, and the concomitant and maximal activities of sulfate-reducers and fermenters led to the near exclusion of methanogens and denitrifiers in the mediation of carbon flow.

Cultural immersion in the education of healthcare professionals: a systematic review

Marty Jacob Brock,Levi Bryant Fowler,Johnathan Gill Freeman,Devan Cord Richardson,Lisa Jayroe Barnes 한국보건의료인국가시험원 2019 보건의료교육평가 Vol.16 No.-

PurposeWith the ever-changing cultural makeup of society, the ability to deliver culturally appropriate healthcare is essential. An educational method aimed at increasing cultural knowledge and sensitivity in the education of healthcare professionals is cultural immersion, which creates opportunities for transformational learning through direct interactions with culturally diverse populations. The purpose of this systematic review was to examine the qualitative effects of cultural immersion experiences on graduate-level healthcare professional students. MethodsA search of the CINAHL (Cumulative Index to Nursing and Allied Health Literature) and ERIC (Education Resources Information Center) databases was performed, utilizing search terms including cultural immersion, cultural sensitivity, educational outcomes, and healthcare professionals. The search was limited to publications within the last 10 years. The articles were screened according to title, abstract, and full-text following the application of inclusion/exclusion criteria. Themes identified within each article were collected and categorized, using a qualitative methodology, into 5 overarching domains to assess the educational experiences. Studies were scored for quality using the qualitative portion of the McGill Mixed Methods Appraisal Tool-2011. ResultsNine studies incorporating a total of 94 participants with experiences in 14 culturally diverse environments revealing 47 individually identified themes were included in the review. The results indicated that all cultural immersion experiences stimulated increased cultural awareness and sensitivity. ConclusionCultural immersion experiences produced a positive, multi-domain effect on cultural learning in students of the health professions. The results of this review provide support for implementing cultural immersion experiences into the education of healthcare professionals with the goal of increasing cultural sensitivity.

메타버스에서 디즈니를 꿈꾼다

MARTY SWANT 중앙일보에스 2022 Forbes Korea = 포브스 코리아 Vol.2022 No.6

Analytical model for transfer length prediction of 13 mm prestressing strand

Marti-Vargas, J.R.,Arbelaez, C.A.,Serna-Ros, P.,Navarro-Gregori, J.,Pallares-Rubio, L. Techno-Press 2007 Structural Engineering and Mechanics, An Int'l Jou Vol.26 No.2

An experimental investigation to determine the transfer length of a seven-wire prestressing strand in different concretes is presented in this paper. A testing technique based on the analysis of bond behaviour by means of measuring the force supported by the prestressing strand on a series of specimens with different embedment lengths has been used. An analytical bond model to calculate the transfer length from an inelastic bond stress distribution along the transfer length has been obtained. A relationship between the plastic bond stress for transfer length and the concrete compressive strength at the time of prestress transfer has been found. An equation to predict the average and both the lower bound and the upper bound values of transfer length is proposed. The experimental results have not only been compared with the theoretical prediction from proposed equations in the literature, but also with experimental results obtained by several researchers.

La poli´tica cultural en Cuba

Marti´nez, Roberto Me´ndez 서울大學校 스페인中南美硏究所 2000 이베로아메리카硏究 Vol.11 No.-

No es posible referirse a la politica cultural cubana de este momento sin detenerse, aunque sea un instante, en los rasgos fundamentales que definen la cultura de nuestra nacion y en sus nexos con la vida social. Cuba comienza el siglo XIX con tres siglos de dominacio´n colonial a sus espaldas. Espan~a, como escribira´ an~os despue´s el partiota Carlos Manuel de Ce´spedes en su Manifiesto del 10 de octubre, "gobierna a la Isla con brazo de hierro ensangrentado", pero no puede impedir que emerja un pensamiento que resulta deudor en cierta medida del pensamiento dela Ilustracio´n europea del siglo ⅩⅤⅢ y con ella, del ideal de la Modernidad. Estos intelectuales, formados en universidades europeas o en una importante institucio´n educacional cubana: el Seminario de San Carlos y San Ambrosio, son lectores de Voltaire, Rousseau, Montesquieu, algunos de ellos vieron con simpatia la Revolucio´n Francesa y en lo esencial coincidian en abogar por la abolicio´n de la esclavitud y la instauracio´n en la Isla de un capitalismo al estiloingle´s, por la obencio´n de reformas politicas que dieran un estatuto auto´nomo al pais -en algunos casos, como el del Padre Fe´lix Varela, abogaba francamente por la completa independencia y en lo cultural por una reforma de la educacio´n y el desarrollo de instituciones ajenas al sistema colonial: bibliotecas, liceos, ca´tedras, desde las que se expresaran las e´lites ilustradas, pues estaban convencidos de que el destino del pais estaba estrechamente asociado al crecimiento y expansio´n de su cultura.