X-ray natural birefringence in reflection from graphene

Jansing, C.,Mertins, H.-Ch.,Gilbert, M.,Wahab, H.,Timmers, H.,Choi, S.-H.,Gaupp, A.,Krivenkov, M.,Varykhalov, A.,Rader, O.,Legut, D.,Oppeneer, P. M. American Physical Society 2016 Physical Review B Vol.94 No.4

<P>The existence of natural birefringence in x-ray reflection on graphene is demonstrated at energies spanning the carbon 1s absorption edge. This new x-ray effect has been discovered with precision measurements of the polarization-plane rotation and the polarization-ellipticity changes that occur upon reflection of linearly polarized synchrotron radiation on monolayer graphene. Extraordinarily large polarization-plane rotations of up to 30 degrees, accompanied by a change from linearly to circularly polarized radiation have been measured for graphene on copper. Graphene on single crystalline cobalt, grown on tungsten, exhibits rotation values of up to 17 degrees. Both graphene systems show resonantly enhanced effects at the pi* and sigma* energies. The results are referenced against those obtained for polycrystalline carbon and highly oriented pyrolytic graphite (HOPG), respectively. As expected, polycrystalline carbon shows negligible rotation, whereas a huge maximum rotation of 140 degrees has been observed for HOPG that may be considered a graphene multilayer system. HOPG is found to exhibit such large rotation values over a broad energy range, even well beyond the pi* resonance energy due to the contributions of numerous graphene layers. To explain the origin of the observed natural birefringence of graphene, the Stokes parameters as well as the x-ray natural linear dichroism in reflection have been determined. It is shown that the birefringence directly results from the optical anisotropy related to the orthogonal alignment of pi* and sigma* bonds in the graphene layer. Our polarization analysis reveals a strong bonding of graphene on Co with a reduced sigma* excitation energy and a strong tilt of 50% of the p(z) orbitals towards diagonal orientation. In contrast, graphene on Cu is weakly bound with an orthogonal orientation of the p(z) orbitals. Exhibiting such a large natural birefringence that can be controlled through substrate choice, and because of excellent heat conductivity, graphene materials have a potential to be used as tunable x-ray phase shifting lambda/4 or lambda/2 plates in the design of future high-intensity light sources.</P>

The identification and characterisation of carbonaceous interface layers of graphene using polarisation-dependent X-ray reflectometry

Wahab, H.,Jansing, C.,Mertins, H.-Ch,Kim, J.H.,Choi, S.-H.,Gaupp, A.,Timmers, H. Elsevier 2018 Carbon Vol.137 No.-

<P><B>Abstract</B></P> <P>The complex refractive index has been determined for graphene for linearly polarised light in p- and s-geometry at energies across the carbon 1s edge. The imaginary part was measured with absorption spectroscopy. The real part was derived using Kramers-Kronig transformations. Results have been validated by X-ray reflectometry of substrate-supported graphene. Theoretical modelling demonstrates that reflection spectra are strongly affected by the relative difference between the reflectance of graphene and its substrate. Measured reflection spectra show that graphene is often sandwiched between a carbonaceous layer of surface-adsorbates and another carbonaceous layer between graphene and substrate. Reflectometry distinguishes adventitious layers from the graphene because of a different energy-dependence of the refractive index. The carbonaceous interface layers can be modelled well with the refractive index function measured for an adventitious surface layer on silicon. The carbon observed at the substrate-interface may originate from the transfer of a graphene sheet from a deposition-substrate. The optically-effective thickness and anisotropy of adventitious carbonaceous layers can be extracted from reflectance spectra. The bonds of adventitious carbon tend to be normal to the basal plane of graphene. Transferred graphene typically has a substrate-interface three times its own thickness and is covered by one layer of surface adsorbates.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

무형문화유산과 사회 젠더 구조: 일본 장식 수레 축제의 젠더 역할 변화와 젠더 제약에 관한 인터뷰 연구

Helga Janse 국립민속박물관 2021 International Journal of Intangible Heritage Vol.16 No.2

문화유산과 젠더는 밀접하게 연결되어 있다. 이러한 연결은 특히무형문화유산 분야에서 명료하게 드러나는데, 많은 전통 관행들이참여와 접근에 있어서 젠더특징적한쪽 성에 치우치는 규칙을가지고이 있기 때문이다. 그러나 전통적인관행전통 관행에서 젠더는잠재적으로 논쟁의 여지가 있는 소재이기 때문에, 이 주제에 대한연구는 여전히 부족하다. 본 논문은 젠더 제약의 변화가 발생한 7 개의 장식 수레 축제의를 선정과, 이와 관련하여된 보존 협회와수행한 인터뷰 연구 결과를 제시한다. 인터뷰 대상자들은 젠더제약에서 일어난 변화와 지역사회에서의 논의에 대해 질문을 받았다. 그 결과는 축제 간 젠더 구조 측면에서의 유사점과, 젠더 제한적참여에 대한 태도의 차이점을 보여준다. 이 연구는 과거 남성전용이었던 역할들에 여성 참여가 가능해졌지만, 여성들이 접근할 수있는 역할에는 한계가 있으며, 고위직은 여전히 남성의 영역이라는것을 밝혔다. 축제 내의 조직 구조는 더 넓은 사회 구조의 반영으로볼 수 있으며, 더 높아진 포용력을 향한 변화가 일어났지만, 근본적인권력 구조는 유지되고 있다. 이와 같이, 연구 결과는 사회 구조와유산 관행 사이의 연관성을 강조하고 전통적인 관행전통 관행의현대성을 강조한다.

UNESCO’s Convention for the Safeguarding of the Intangible Cultural Heritage and the ‘goodness criteria’

Helga Janse 국립민속박물관 2023 International Journal of Intangible Heritage Vol.18 No.-

This paper discusses UNESCO’s 2003 Convention for the Safeguarding of the Intangible Cultural Heritage and specifically the challenges connected to article 2 and the ‘goodness criteria’ included in the Convention’s definition of intangible cultural heritage (ICH). The interpretation of these criteria and the practical implementation of them has proven challenging, and the question of how to handle human rights considerations within the framework of the Convention is an unresolved problem. As the question whether a traditional practice is, for example, discriminatory is often a contentious matter, and as traditional practices sometimes fall within a ‘grey area’, the topic of discrimination tends to be easier to avoid than to address. Another important factor in this is the notion of heritage as ‘good’. In contrast to the World Heritage Convention, the 2003 Convention does not recognise so-called negative, contested or difficult heritage. The inclusion of the goodness criteria can be seen as a fundamentally important statement, assuring that due attention is given to human rights considerations and that discriminatory practices are not to be included. At the same time, the goodness criteria have not been strictly applied, which can be seen, for example, in the handling of gender. In this paper, the author discusses problems related to the current approach to the ‘goodness criteria’, and as a hypothetical exercise, draws up four alternative scenarios.

Intangible cultural heritage and societal gender structures: An interview study focusing on changes in gender roles and gender restrictions in Japanese float festivals

Helga Janse 국립민속박물관 2021 International Journal of Intangible Heritage Vol.16 No.1

Cultural heritage and gender are connected. This connection is arguably particularly articulated within the field of intangible cultural heritage, seeing as many traditional practices have gender-specific rules regarding participation and access. Because gender within traditional practices is a potentially contentious topic, however, research on this subject remains scarce. This paper presents the results of an interview study conducted with preservation associations connected to a selection of seven float festivals where changes in the gender restrictions have occurred. The interviewees were asked about the changes that had occurred in the gender restrictions and about discussions in the local communities. The results reveal similarities in terms of gender structure between the festivals and differences in terms of displayed attitude towards gender-restricted participation. The study finds that, while roles that were previously male-exclusive have opened up for female participation, there is a limit to the roles made accessible to women, and the top positions continue to be male domains. The organizational structures within the festivals can be seen as reflections of wider societal structures and, while changes have happened in the direction of increased inclusion, the underlying power structures have remained intact. As such, the findings underline the connection between societal structures and heritage practices and emphasize the contemporary nature of traditional practices.

Painless colonoscopy: fact or fiction?

Pieter Sinonquel,Alexander Jans,Raf Bisschops 대한소화기내시경학회 2024 Clinical Endoscopy Vol.57 No.5

Although colonoscopy is a routinely performed procedure, it is not devoid of challenges, such as the potential for perforation and considerable patient discomfort, leading to patients postponing the procedure with several healthcare risks. This review delves into preprocedural and procedural solutions, and emerging technologies aimed at addressing the drawbacks of colonoscopies. Insufflation and sedation techniques, together with various other methods, have been explored to increase patient satisfaction, and thereby, the quality of endoscopy. Recent advances in this field include the prevention of loop formation, encompassing the use of variable-stiffness endoscopes, computer-guided scopes, magnetic endoscopic imaging, robotics, and capsule endoscopy. An autonomous endoscope that relies on self-propulsion to completely avoid looping is a potentially groundbreaking technology for the next generation of endoscopes. Nevertheless, critical techniques need to be refined to ensure the development of effective and efficient endoscopes.

A Modified Robust Adaptive Beamformer for Microphone Arrays

Young-Ho Lee,Su-Young Choi,Jans-Sik Park,Kyung-Sik Son 한국멀티미디어학회 2003 한국멀티미디어학회 학술발표논문집 Vol.2003 No.1

우리나라 비성장형도시의 특성분석에 관한 연구

송상열(Song, Sang-Yeoll),장희순(Jans, Hee-Soon) 한국지역개발학회 2007 韓國地域開發學會誌 Vol.19 No.2

The Purposes of this study are to identify the structural and whole features which the non-growing type cities are currently faced with and provide the positive data which can promote them to be changed into the growing cities. Most of Non-Growing Type Cities are the small towns which are not more than hundreds of thousands in populations and have the features including (1) continuous decrease in population (especially for young ages) and aging phenomena, (2) changing into nuclear family and a-few-children family, (3) concentration of lower residing class, (4) urban industrial lag and fiscal and budgetary shortage due to it, (5) weak educational and cultural base, (6) poor urban infrastructure, (7) sudden decline of downtown and 7) alienation of development opportunity according to the unbalanced development strategy by the government. Therefore the additional outflow of population should be prevented, and the strong polities are followed against the influx of the overcetralized population in the metropolitan area. In order for this, the development of industries, the growth in income through increased employment rate, improvement of educational and cultural service as a central function, created culture or tourism utilizing the cultural resources, fiscal and budgetary improvement and maintenance of urban infrastructure, centralized support by the central government are necessary. Thus the population settlement foundation of the non-growing cities will be established firmly, and ultimately will perform their roles as the small towns which are required in the urban system and be born as growing cities through getting the foothold for growth.

The Listening Cube: A Three Dimensional Auditory Training Program

De Raeve Leo,Anderson Ilona,Bammens Marleen,Jans Josepha,Haesevoets Marianne,Pans Ria,Vandistel Hilde,Vrolix Yvette 대한이비인후과학회 2012 Clinical and Experimental Otorhinolaryngology Vol.5 No.2

Lightscapes_displacement maps

Manuel Abendroth,Jerome Decock,Naziha Mestaoui,Kim Pecheur,Pieter Desmedt Jans 현대건축사 2003 월간 CONCEPT Vol.- No.57