234 research outputs found
Progress and Prospects of Nanoscale Emitter Technology for AR/VR Displays
No full textAugmented reality (AR) and virtual reality (VR) are emerging interactive technologies that realize the "metaverse," leading to a totally new digital interactive experience in daily life in various aspects. In order to provide users with a more immersive experience, displays for AR/VR have rapidly evolved to achieve high resolutions and a large color gamut on small panels. Recently, nanoscale light emitters such as quantum dots (QDs) and metal halide perovskites (MHPs) with high photoluminescence quantum efficiency and color purity levels have garnered much attention as color conversion materials in AR/VR displays. However, the low material stability and the absence of a high-resolution patterning process that does not impair the optical properties of nanoscale emitters act as obstacles preventing the realization of high-resolution AR/VR displays. Here, the state-of-the-art technologies constituting current AR/VR devices are reviewed from an industrial point of view and the recent progress in QD and MHP emitter technologies are discussed, including their basic structural properties, synthesis strategies to enhance the stability, advanced patterning technologies, down-conversion and light-emitting diode applications. Based on the review, the authors' perspective on future research directions of nanoscale emitters for next-generation AR/VR displays is presented.N
Molecular dynamics studies of interactions between Arg9(nona-arginine) and a DOPC/DOPG(4:1) membrane
No full textIt has been known that the uptake mechanisms of cell-penetrating peptides (CPPs) depend on the experimental conditions such as the concentration of peptides, lipid composition, and temperature. In this study, we investigate the temperature dependence of the penetration of Arg 9 s into a DOPC/DOPG(4:1) membrane using molecular dynamics (MD) simulations at two different temperatures, T = 310 K and T = 288 K. Although it is difficult to identify the temperature dependence because of having only one single simulation at each temperature and no evidence of translocation of Arg 9 s across the membrane at both temperatures, our simulations suggest that following are strongly correlated with the penetration of Arg 9 s: a number of water molecules coordinated by Arg 9 s and the electrostatic energy between Arg 9 s and the lipid molecules. We also present how Arg 9 s change a bending rigidity of the membrane and how a collective behavior between Arg 9 s enhances the penetration and the membrane bending. Our analyses can be applicable to any CPPs to investigate their interactions with various membranes using MD simulations. © 2020 Author(s).1
Global trends in raw materials consumption
No full textThis paper reviews movements in raw materials consumption over the past 30 years. Included in this review are all base metals and steel, and important agricultural raw materials. These primary commodities share the common characteristic that they are used as inputs in manufacturing and construction. Some metals and minerals, energy commodities, and timber products are not included in this review for various reasons. The period reviewed is from 1961 to 1988. A prominent characteristic of the metals market during the past 15 years has been its very slow growth. In some years consumption of several raw materials has even declined. Explaining the causes of this slowdown, in the face of moderate economic growth, has become a topical issue. The slowdown has important implications for a number of developing countries that rely heavily on exports of these materials. The severity and persistence of post-1973 declines in metals intensity per unit of GNP, prompted the conjecture that it may have been structural. This paper reviews the debate on this issue, including results of statistical tests. It also summarizes the trends in raw materials consumption and reviews the technological developments relating to raw materials consumption.Mining&Extractive Industry (Non-Energy),Montreal Protocol,Sanitation and Sewerage,Primary Metals,Environmental Economics&Policies
The precautionary demand for commodity stocks
No full textThis paper develops a theory of the precautionary demand for commodity stocks. It suggests that commodity stocks are held for precautionary purposes by producers, consumers, and intermediate processors, while speculators hold stocks on the expectation of capital gains from a subsequent price rise. Producer and consumer stocks usually account for the largest share of commercial stocks held at any point in time. For example, at the end of 1990, stocks held by producers and consumers of copper were 72 percent of all commercial stocks of the market economy countries. Yet, the theory explaining the behavior of this class of stocks has not progressed much beyond the concept of convenience yield, first introduced by Kaldor (1939). This paper proposes an alternative theory. Holding of stocks by producers and consumers is viewed as precautionary behavior towards output and price risks. As a theory of behavior towards risks, the precautionary stock demand model encompasses speculative demand by both producers and consumers. Furthermore, both stocks and futures are treated as precautionary instruments, in contrast to the dichotomy that only stocks provide convenience yield while futures are hedging instruments.Access to Markets,Markets and Market Access,Economic Theory&Research,Environmental Economics&Policies,Non Bank Financial Institutions
Empires of the Metoikoi : T.S. Eliot, Nishida Kitaro, Choe Chaeso
No full text本論考は,T.S.エリオットの「伝統と個人の才能」(1919年)が,帝国日本の思想家・西田幾多郎および植民地朝鮮の「親日派」・崔載瑞というふたりの知識人によって「誤読」された事例をめぐって,そもそもエリオットのmetoikos(居留外国人)的主体性に潜在していたイデオロギー素の解析から,この不気味な「誤読」を生んだ政治的・理論的ドラマの絡まり合いを解きほぐし,その過程で生産され抑圧された「問題」を明るみに出すThis article deals with the two uncanny "misreadings" of T. S. Eliot's "Tradition and the Individual Talent" (1919) by Nishida Kitaro, leading philosopher of the Japanese Empire, and Choe Chaeso, "pro-Japanese" intellectual of Colonial Korea. Analyzing the ideologemes inherent in Eliot's metic [i.e., metoikos] "Tradition", the author attempts to unweave the intertwined political and theoretical dramas involved in these unpredictable disseminations, and to uncover the unique "problems," or "problematics," produced and suppressed through the process.論説(Article)departmental bulletin pape
Structural changes in metals consumption
No full textFor 15 years the metals market has been characterized by slow growth - in some cases, even decline - in consumption. To test the proposition that structural changes in demand were the main cause of the slowdown, the author - drawing on U.S. data - uses an extended metals demand model that recognizes energy, labor, capital, and other materials as major inputs. The traditional model explains metals consumption in terms only of output and the prices of metal and its substitutes. It is inadequate to address the issue of structural change because it ignores other factors of production, such as energy, which have experienced dramatic changes. With the extended model, the null hypothesis of no structural change cannot be rejected for most metals. With the conventional model, the null hypothesis of no structural change is strongly rejected. Results with the extended model show that the downturn can be explained mostly by changes in the input variables, particularly such nonmetal inputs as capital and energy, which are much more important cost items than metals and have undergone drastic cost changes over the period.Environmental Economics&Policies,Economic Theory&Research,Montreal Protocol,Mining&Extractive Industry (Non-Energy),Primary Metals
Variations in Commissural Input Processing Across Different Types of Cortical Projection Neurons
No full text© The Author(s) 2021. To understand how incoming cortical inputs are processed by different types of cortical projection neurons in the medial prefrontal cortex, we compared intrinsic physiological properties of and commissural excitatory/inhibitory influences on layer 5 intratelencephalic (IT), layer 5 pyramidal tract (PT), and layers 2/3 IT projection neurons. We found that intrinsic physiological properties and commissural synaptic transmission varied across the three types of projection neurons. The rank order of intrinsic excitability was layer 5 PT > layer 5 IT > layers 2/3 IT neurons. Commissural connectivity was higher in layers 2/3 than layer 5 projection neurons, but commissural excitatory influence was stronger on layer 5 than layers 2/3 pyramidal neurons. Paired-pulse ratio was also greater in PT than IT neurons. These results indicate that commissural inputs activate deep layer PT neurons most preferentially and superficial layer IT neurons least preferentially. Deep layer PT neurons might faithfully transmit cortical input signals to downstream subcortical structures for reliable control of behavior, whereas superficial layer IT neurons might integrate cortical input signals from diverse sources in support of higher-order cognitive functions.11Nsciescopu
Anisotropic in-plane thermal conductivity of black phosphorus nanoribbons at temperatures higher than 100 K
No full textabstract: Black phosphorus attracts enormous attention as a promising layered material for electronic, optoelectronic and thermoelectric applications. Here we report large anisotropy in in-plane thermal conductivity of single-crystal black phosphorus nanoribbons along the zigzag and armchair lattice directions at variable temperatures. Thermal conductivity measurements were carried out under the condition of steady-state longitudinal heat flow using suspended-pad micro-devices. We discovered increasing thermal conductivity anisotropy, up to a factor of two, with temperatures above 100 K. A size effect in thermal conductivity was also observed in which thinner nanoribbons show lower thermal conductivity. Analysed with the relaxation time approximation model using phonon dispersions obtained based on density function perturbation theory, the high anisotropy is attributed mainly to direction-dependent phonon dispersion and partially to phonon–phonon scattering. Our results revealing the intrinsic, orientation-dependent thermal conductivity of black phosphorus are useful for designing devices, as well as understanding fundamental physical properties of layered materials.The final version of this article, as published in Nature Communications, can be viewed online at: https://www.nature.com/articles/ncomms957
- …
