1,364 research outputs found
Frontal brain functioning and pain: Possible underlying mechanisms of increased pain responses in age- and dementia-related cognitive impairment
No full textIn dit proefschrift heb ik onderzoek gedaan naar pijn bij dementie. Dementie kenmerkt zich door neurodegeneratie, het afsterven van zenuwcellen in de hersenen. Hierdoor kunnen mensen met dementie onder andere niet meer goed aangeven dat zij pijn hebben. Op basis van eerder onderzoek was bovendien het vermoeden dat mensen met dementie gevoeliger worden voor pijn, mogelijk door neurodegeneratie in met name het voorste deel van de hersenen (de frontale cortex). In een experimentele pijnstudie heb ik onderzocht of mensen met dementie anders reageren op pijnprikkels dan cognitief gezonde ouderen. Ik onderzocht specifiek het vermogen om pijn te remmen. Omdat mensen met dementie moeite kunnen hebben met het aangeven van pijn, werd pijn niet alleen gemeten door aan de deelnemers te vragen hoe pijnlijk de pijnprikkels waren, maar ook aan de hand van gezichtsuitdrukkingen. Alle deelnemers ondergingen ook een structurele MRI scan van de hersenen, zodat ik kon onderzoeken of reacties op de pijnprikkels zijn gerelateerd aan de hersenstructuur. Het belangrijkste resultaat van dit proefschrift is dat mensen met dementie verhoogde pijnreacties hadden in vergelijking met cognitief gezonde ouderen. Zo konden mensen met dementie bijvoorbeeld minder goed pijn remmen. De verschil was alleen te zien wanneer pijn werd gemeten aan de hand van gezichtsuitdrukkingen en niet wanneer gevraagd werd hoe pijnlijk de pijnprikkels waren. Het verminderd vermogen om pijn te remmen was, zoals werd vermoed, geassocieerd met neurodegeneratie in de frontale cortex. Dit onderzoek laat hiermee zien dat mensen met dementie door de schade in de hersenen mogelijk gevoeliger zijn voor pijn dan gezonde ouderen
Sketches for the biography of S.F. Rusova (1856–1940)
No full textМета статті – проаналізувати відомі факти біографії С.Ф. Русової, аби визначити, як вона,
попутниця діячів українського ліберально-демократичного та російського народницького рухів, визначилася й скерувала свою надзвичайну енергію на українську справу. Методи: історико-систематичний та аналітичний. Наукова новизна: уперше звернено увагу не на просвітницьку та педагогічну діяльність, про яку написано багато статей і книг, а власне на біографію С.Ф. Русової, яка
складається з двох частин: української та емігрантської. Висновки: український період її життя
визначається роздвоєнням політичної думки – між українством і російським визвольним рухом. В
еміграції 65-річна С.Ф. Русова, потрапивши в українське середовище, яке впливало на перебіг та
кристалізацію національного руху, віддано служила українству. За основу статті взято книжку
С.Ф. Русової «Мої спомини» (1937), видану у Львові кооперативним видавництвом «Хортиця», заснованим групою емігрантів із Наддніпрянщини наприкінці 1928 р. У передмові чітко визначена позиція видавництва як до авторки спогадів, так і до їх змісту. Вона близька авторці цієї статті.
Видавці зазначають, що в мемуарах зображені різні постаті: ті, які брали активну участь в українському визвольному процесі, і ті, котрі лише «творили близьке балянсування між українством і
загально-московським визвольним рухом» та відзначалися роздвоєнням політичної думки. С.Ф. Русова, на наш погляд, належала до других. Лише в еміграції в Празі вона стала свідомою українкою.
Цей заключний етап життя Софії Федорівни – тема для іншої студії. Автором же окреслений
життєпис С.Ф. Русової в Україні від дитинства до 1921 р., коли вона змушена була залишити
Батьківщину. Ця стаття – лише скромні начерки, в яких відображено діяльність ліберальної української інтелігенції 1870-х рр. – поч. ХХ ст. у контексті того, що в їхньому середовищі відбувався
процес духовного формування С.Ф. Русової, створювався ідейний багаж і моральні норми та образ
життя розумної, освіченої, суперечливої, гонорової жінки, яка постійно перебувала в процесі доволі напружених, болісних шукань.The purpose of the article – is to analyze the known facts of the biography of S.F. Rusova, in order to
determine how she, a fellow traveler of the Ukrainian liberal-democratic and Russian populist movements,
finally made up her mind and directed her extraordinary energy to the Ukrainian cause. Methods: historical-
systematic and analytical. Scientific novelty: for the first time, attention is drawn not to educational
and pedagogical activities, about which many articles and books have been published, but to the biography
of S.F. Rusova, which consists of two parts: Ukrainian and emigrant. Conclusions: the Ukrainian period of
her life is characterized by a bifurcation of political opinion – between Ukrainianism and the Russian liberation
movement. During her emigration, 65-year-old S.F. Rusova, by the will of fate, found herself in the
Ukrainian environment, which influenced the course and crystallization of the national movement, devotedly
served the Ukrainian nation. The basis of the article is the book «My memories» (1937) by S.F. Rusova,
published in Lviv by the cooperative publishing house «Khortytsia», founded by a group of emigrants from
the Naddniprianshchyna at the end of 1928. The preface clearly defines the position of the publishing house
both towards the author of the memoirs and their content. This position is close to the author of this
article. The publishers note that the memoirs depict different people: those who took an active part in the
Ukrainian liberation process and those who only «created a close balance between Ukrainianness and the
all-Moscow liberation movement» and were marked by a split in political opinion. S.F. Rusova, in our opinion,
belonged to the second ones. She became a conscious Ukrainian only when she emigrated to Prague.
This final stage of Sofia Fedorivnaʼs life is a topic for another studio. The author also outlines the biography
of S.F. Rusova in Ukraine from her childhood until 1921, when she was forced to leave the Motherland.
This article is only a modest sketch, which reflects the activities of the liberal Ukrainian intelligentsia
of the 1870s – the beginning of the 20th c. in the context of the fact that in their environment the process of
spiritual formation of S.F. Rusova took place, ideological baggage and moral norms and a way of life were
created an intelligent, educated, controversial, honorable woman who was constantly in the process of
quite intense, painful searches
Scientific Research Methodology for Library & Information Science Research: With Information System Development Methodology as Example
No full text近年來圖書館學與資訊科學有學科領域融合的現象。因為學科領域融合的結果，學科內涵的包容範圍擴大；過去傳統的圖書館學之研究，比較多關於社會科學層面之研究，因此，社會科學的研究方法，已在圖書館學的研究中，成為成熟化的一套研究方法。但是，自從圖書館自動化與資料庫系統建置也成為圖書館學中重要的一環之後，圖書館學的科學層面之研究益形重要，然而相對的研究方法，在圖書館學的研究中，並不及社會科學的研究方法一般成熟。為了幫助圖書館學中的技術科學領域，尋找更能有效解決問題的方法，以提升作業績效與服務上的讀者滿意度，本文乃研究有關科學研究方法的理論，參酌資訊科學領域的學者對於研究方法的見解，以系統開發的研究為例，彙整可行的一套研究方法，而論述科學技術性的作業與系統開發等相關研究，可以採用科學研究的方法。本文除了討論圖書資訊學科學研究法的基本精神與可能的步驟之外，並分析科學研究法的實質效益，希望能為圖書資訊學中的技術科學研究，指出可行的研究途徑，冀期圖書館學的科學研究方法終能發展至成熟之水準，而裨益日益重要的圖書館學之相關科學研究。The cross boundary research between library science and information science shows a great advancement in recent years. In the past, discourse of most researchers in library science had their focus on social aspects; therefore, the adopted sociology research methodologies have developed to a sophisticated level. In fact, the cross-disciplinary development has brought changes to library science research paradigm. With the broader scope of current library and information sciences, it would be very useful if we could also develop suitable research methodology for scientific researches. It is believed that
suitable research methodology could help solve problems in an effective way so as to ensure good operational performance and user satisfaction. Reviewing some theories
of scientific researches and scholars opinions regarding information science research methodologies, the author had information system development research as an example
and advocated that researches concerning technical services of library science needed to adopt scientific research methodologies. The author also introduced the positive heuristic
research approach and associated aspects that need to be included in the process for scientific researches of information system development and pointed out the possible
benefits of a scientific research approach for such researches. It is hoped that this initial discussion could anticipate the development of a set of sophisticated scientific research
methodology for library science researchers and be beneficial
Interferometric coherent Fourier scatterometry: a method for obtaining high sensitivity in the optical inverse-grating problem
No full textGreen Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public. 075707-1 t/m 075707-9ImPhys/Optic
Phytofiltration of arsenic and cadmium from the water environment using Micranthemum umbrosum(J.F. Gmel) S.F. Blake as a hyperaccumulator
No full textArsenic (As) and cadmium (Cd) pollution in water is an important global issue. Phytofiltration is an eco-friendly technology that helps clean up pollutants using ornamental plants, such as Micranthemum umbrosum (J.F. Gmel) S.F. Blake. After a seven-day hydroponic experiment, M. umbrosum removed 79.3–89.5% As and 60–73.1% Cd from 0 to 1.0 μg As mL–1 and 0.3 to 30.0 μg Cd mL–1 solutions, respectively. For As treatment, root to stem and stem to leaf translocation factors greater than 1.0 indicated that accumulation of As in leaves was large compared to that in stem and roots. However, the accumulation of Cd in roots was higher than that in the leaves and stem. In addition, M. umbrosum completely removed Cd within three days from 0.38 to around 0 μg mL–1Cd in the solution when the plant was exchanged daily. Bio-concentration factors (2350 for As and 3027 for Cd) for M. umbrosum were higher than for other As and Cd phytoremediators. The results show that M. umbrosum can be an effective accumulator of Cd and a hyper-accumulator of As, as it can lower As toxicity to a level close to the limit recommended by the World Health Organization (0.01 μg As mL–1
Absorbing new subjects: holography as an analog of photography
No full textI discuss the early history of holography and explore how perceptions, applications, and forecasts of the subject were shaped by prior experience. I focus on the work of Dennis Gabor (1900–1979) in England,Yury N. Denisyuk (b. 1924) in the Soviet Union, and Emmett N. Leith (1927–2005) and Juris Upatnieks (b. 1936) in the United States. I show that the evolution of holography was simultaneously promoted and constrained by its identification as an analog of photography, an association that influenced its assessment by successive audiences of practitioners, entrepreneurs, and consumers. One consequence is that holography can be seen as an example of a modern technical subject that has been shaped by cultural influences more powerfully than generally appreciated.
Conversely, the understanding of this new science and technology in terms of an older one helps
to explain why the cultural effects of holography have been more muted than anticipated by forecasters
between the 1960s and 1990s
Coherent fourier scatterometry
No full textThe electronics which makes our lives easier like mobiles, computers, digital cameras contain chips with very small semiconductor components like transistors. When transistors can be made even smaller, the chip can accommodate a larger number of components, which gives more processing capacity, resulting in a faster device with an increased functionality. Industrial lithography, the art of making structures on wafers, follows Moore’s law (1970’s), which states that “the processor speed, or overall processing power for computers would double almost every two years”, i.e., the number of transistors in an integrated circuit would double almost every two years. The implications of this law is clearly seen in the evolution of electronic devices where smaller, lighter and faster computers, high resolution imaging sensors, increased storage capacity are continuously being introduced in the market. But this also sets stringent requirements on lithography processes. The critical dimension printed on a wafer these days are in order of a few tens of nano-meters which in perspective is approximately 1000 times smaller than a strand of human hair. The technology nodes and the uniformity of the line-width or critical dimension (CD) over the wafer as produced by lithographic scanners must be improved in future for an optimal yield and performance of the electronic components. Now, the question is how to design a measurement method that is able to quantify the printing quality of these small features in a fast, stable and non destructive way which can also be incorporated into the machine which makes these chips? When you can measure something and express it in numbers, you know something about it. Lord Kelvin's statement is frequently paraphrased as ``if you can measure something, you can make it better". The research work presented in the thesis is a step forward in that direction, regarding wafer inspection. In the semiconductor industry, a robust, reliable and repeatable in-line control process is required to obtain the intended line shapes and sizes. This is achieved by printing special targets on the wafer, typically gratings, which are successively measured in order to adjust dose, exposure time, overlay/alignment and other relevant process parameters of the photo-lithographic machine. As the specifications get tighter, the measuring technique has to be more accurate. This is the primary reason for the continuous development of increasingly complex, advanced and improved quantitative metrology techniques over the years. Currently, in the semiconductor industry, incoherent optical scatterometry (IOS) is the standard workhorse. Any degree of improvement in the present technique is worthwhile of scientific and technological interest. In this thesis we develop, study, design and implement coherent Fourier scatterometry (CFS). The scatterometer is based on a coherent source of illumination, where a focused spot interacts with the sample. The performance of CFS is compared with IOS in terms of sensitivity to the change in grating shape parameters. The studies are done on grating as samples for the performance comparison. The grating reconstruction is proved with the experimental implementation of a CF scatterometer. Applications and improvements in CFS are also discussed in the thesis. The thesis starts with an introduction to the research goals and scope of CFS in chapter 1. The grating diffraction formula, which predicts the angle of diffraction for a given incidence angle on the grating is explained and the relevance of rigorous coupled wave analysis popularly known as RCWA as a rigorous Maxwell’s solver for periodic structure are highlighted. A brief introduction to principle of the Shack-Hartmann sensor used in experiments is also mentioned. This chapter also contains a summarized description of the work done within the PhD period but are not in the scope of the description in the thesis. In chapter 2 of the thesis, a framework to study the increment in sensitivity of CFS with respect to the IOS and the benefits of using a focused spot from a spatially coherent source (laser) is investigated on a theoretical viewpoint. A specific model of the grating and the illumination is presented, where the grating is defined in terms of a finite number of geometrical shape parameters (such as height, side-wall angles, midCD). The focused spot is scanned over the grating, and for each scan position, a far-field diffraction pattern is recorded. Through sensitivity analysis, we show that the use of coherence and multiple scanning makes CFS more sensitive than IOS under special circumstances. The role of the incident and output polarization, the position of the focused spot w.r.t. the grating and the effect of the number of scanning positions on the sensitivity analysis is also studied. There is an optimum number of scanning positions, which depends on the number of diffracted orders in the exit pupil. Owing to the coherent illumination, the far field in CFS comprise phase information concealed in the complex reflection matrix of interaction. Intensity data with phase between scattered orders is the maximum information that can be extracted in CFS. Unravelling the complex reflection matrix in CFS requires the knowledge of the amplitude and phase of the individual components of the matrix. Intensity measurements provide the amplitude information but the phase information is absent. In chapter 3 of the thesis, we present a non interferometric partial phase retrieval method from the intensity measurements in CFS. The applicability of the principle of temporal phase shifting interferometry (TPSI) in CFS with a scanning spot is presented. An analytical relation is derived and illustrated for the phase difference between two overlapping orders in the exit pupil. The analytic results are compared with the simulations from RCWA. Also, the polarization dependent phase sensitivity of grating parameters is studied for the overlap region of diffracted orders in the exit pupil. In chapter 4, the implementation of an operational CFS instrument in the laboratory environment is reported for grating reconstruction. The setup is capable of illuminating and measuring the response of the sample simultaneously over a broad range of incident and reflected angles and for two orthogonal incident polarizations. The measurement for all radial and azimuthal angles can be performed within a few ms. The system, although currently operating at a relatively low numerical aperture (NA = 0.4) at wavelength 633 nm allows the reconstruction of the grating shape parameters with nano-meter accuracy, which is comparable to that of measured by atomic force microscopy (AFM) and scanning electron microscope (SEM) as the reference measurements. Additionally, nano-meter accuracy in lateral positioning is proven, which in the present used case corresponds to only 0.08% of the period of the grating. In semiconductor lithography, the desired pattern on the wafer is written layer by layer in several steps to realize the finished structure. The positional accuracy of new patterns on the existing ones decides the performance of the circuitry. Deviation of the consecutive layers is called overlay. The allowed deviation is <=0.1% of the critical dimension, which implies the measurement complexity. In chapter 5 of the thesis, a mathematical analysis of the overlay problem shows that the sum of the product of the reflection and transmission coefficients plays an important role in deciding the magnitude of the asymmetry signal. Here we observe that the overlay signal in CFS is larger in magnitude than that of IOS. With simulations, we have shown that CFS is more sensitive to the overlay as compared to an incoherent case. It is also inferred that, by pupil engineering for incident wavefront on the structure, the sensitivity of the overlay signal can be optimized for a given structure. Optical resolution is limited by the incident wavelength and numerical aperture in a far field optical system. In principle, there are two principal parameters can be tuned to improve the resolution, either by decreasing the wavelength or by increasing the NA of the optical system. In chapter 6 of the thesis, we implement a micro solid immersion lens (SIL) to improve the resolution in a scanning near field microscope setup. Numerical and experimental results show the increased resolution, the improvement in the resolution is based on the focused spot size and visibility studies in the SIL based microscope compared to the confocal imaging. It has been shown that micro-SIL can be used for metrology applications with high NA requirement. The idea, implementation and challenges associated with a Fourier scatterometer with a micro-SIL is presented in the chapter. The fabrication process for the grating involves chemical and plasma treatment which can seldomly result in an unwanted surface over-layer on the nominal structure. When the feature size of the grating is in few tens of nano-meters, an additional layer of few nano-meters on the grating is expected to change the far field diffraction of the grating, compared to an absence of the surface over-layer. In CFS the shape parameters are determined inversely from the far field intensity in grating reconstruction. In the chapter 7 of the thesis, assuming that the distribution of the surface layers (for example: native silicon oxide, contamination and traces of resist removal) are identical on the wafer area with and without the structure, the effect of the thickness of oxide layer on the Si-etched grating is studied and investigated using inverse grating reconstruction. Optical properties of the surface over-layer are measured by ellipsometry and the error, and the accuracy in grating parameters reconstruction in presence of an oxide layer is presented. Finally the grating parameters reconstruction shows that effect of the surface over-layer is crucial for the determination of right set of grating parameters. The accuracy in determination of the refractive index of the over-layer is a critical issue for the actual height determination of the over-layer. Once determined, then CFS is able to resolve few nano-meters of unintentional surface over-layer on the grating structure. Although the studies in the thesis are carried out for periodic structures such as gratings, the applications of CFS are not limited to periodic structures but can also can be applied to multilayer structures analysis, material sciences, photonics industry, bio-sensing, detection of isolated structures and other forms of non-contact metrology. Nevertheless, CFS can also be extended to the interferometric Fourier scatterometry and the ellipsometric Fourier scatterometry with slight modification in the design of the scatterometer for additional functionality and increased sensitivity.ImPhys/Imaging PhysicsApplied Science
New method for solving the Navier-Stokes equations with artificial relations between variations of quantities, applied at nearest nodes
No full textWith the use of the Newton method, a new numerical method previously published [1] for solving the three-dimensional Navier-Stokes equations, is theoretically proved for the most simple case of one-dimensional acoustic equations. The convergence of iteration scheme is proved. In this paper, we also recall some theoretical and numerical results presented earlier in [1]. The gradient of internal energy (see [1]) has to be redefined. This yielded in [1] that, along with descending temperature of internal walls, some small variations of balance of mass arose within the flow of a gas heated from its motion along tube walls. The author succeeded [1] in achieving the maximal time step Dtmax=h/uflow (h is the average size of cell, uflow stands for the flow velocity) along with the condition that, on every step, the required computation time exceeds approximately 6 times the time necessary for computation via an explicit scheme. Every step requires a number of arithmetic operations of order of N; here N is the number of nodes and cells. The stability and velocity of convergence were estimated in a numerical experience. Satisfactory correlation is obtained between the analytic and computed balances of mass in a tube for a given wall temperature dependence. Next, briefly, the idea of the method includes an artificial binding of unknowns' corrections at neighbouring nodes or cells; the respective corrections are determined not via solving bounded system of equations, but in a way directly based on the residual of equation for the corresponding unknown at either a node or a cell. A staggered arrangement of variables is used, this means that the pressure, density, and internal energy are located at the usual cell centres, whereas the velocity vectors are positioned at the displaced cell centres which are the vertices of usual cells. The three-dimensional Navier-Stokes equations are solved via the Newton iteration procedure. The initial guesses are taken for the time t + Dt as known values for time t, and the time step Dt is chosen with the requirement to provide the convergence within an approximately given number of iterations; then the divergence will be avoided due that restriction of time step. The introduction of artificial relations between the variations of quantities at the nearest nodes or cells and the use of approximate equality with opposite signs of vectors relating the geometric coefficients of both displaced and usual cells, make it possible to obtain formulas for correct rates of change of the residuals of equations
Coherent Fourier scatterometry nanoparticle detection enhanced by synthetic optical holography
No full textWe demonstrate that the sensitivity of nanoparticle detection on surfaces can be substantially improved by implementing synthetic optical holography (SOH) in coherent Fourier scatterometry (CFS), resulting in a phase-sensitive confocal differential detection technique that operates at very low power level (P=0.016 mW). The improvement in sensitivity is due to two reasons: first, the boost in the signal at the detector due to the added reference beam; and second, the reduction of background noise caused by the electronics. With this new system, we are able to detect a 60-nm polystyrene latex (PSL) particle at a wavelength of 633 nm (∼λl/10) on a silicon wafer with an improvement in the signalto- noise ratio (SNR) of approximately 4 dB. c 2022 Optica Publishing GroupGreen Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.ImPhys/Optic
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