9,558 research outputs found
RGO/Nylon-6 composite mat with unique structural features and electrical properties obtained from electrospinning and hydrothermal process
In this work, the reduced graphene oxide (RGO) sheets were effectively uploaded through nylon-6 fibers using combined process of electrospinning and hydrothermal treatment. Good dispersion of graphene oxide (GO) with nylon-6 solution could allow to upload GO sheets through nylon-6 fibers and facilitate the formation of spider-wave-like nano-nets during electrospinning. GO sheets present on/into nylon-6 spider-wave-like nano-nets were further reduced to RGO using hydrothermal treatment. The impregnated GO sheets into nylon-6 nanofibers and their reduction during hydrothermal treatment were confirmed by FE-SEM, TEM, FT-IR and Raman spectra. The electrical characteristics of pristine nylon-6, GO/nylon-6 and RGO/nylon-6 nanofibers were investigated and it was found that RGO/nylon-6 composite mat had better electrical conductivity than others. The formation of spider-wave-like nano-nets as well as indirect route of incorporation of RGO sheets on electrospun nylon-6 mat may open a new direction for future graphene/polymer electronics. © 2013 The Korean Fiber Society and Springer Science+Business Media Dordrecht
Bahasa Mentawai
Buku Bahasa Mentawai ini semula merupakan salah satu
naskah laporan penelitian yang disusun oleh tim peneliti dari FKSS IKIP Padang dalam rangka kerja sama dengan Proyek
Penelitian Bahasa dan Sastra Indonesia dan Daerah Sumatra
Barat 1976/1977. Penelitian ini dimaksudkan untuk mendapatkan hal-hal yang mengenai struktur bahasa Mentawai. Dialek yang dipilih ialah dialek yang lebih umum dipakai yaitu dialek Sikakap. Hasil penelitian ini diharapkan agar dapat dipakai sebagai bahan permulaan untuk penelitian-penelitian lebih lanjut yang lebih mendalam mengenai bahasa dan kebudayaan Mentawai di masa yang akan datang
Self-bound dense objects in holographic QCD
We study a self-bound dense object in the hard wall model. We consider a
spherically symmetric dense object which is characterized by its radial density
distribution and non-uniform but spherically symmetric chiral condensate. For
this we analytically solve the partial differential equations in the hard wall
model and read off the radial coordinate dependence of the density and chiral
condensate according to the AdS/CFT correspondence. We then attempt to describe
nucleon density profiles of a few nuclei within our framework and observe that
the confinement scale changes from a free nucleon to a nucleus. We briefly
discuss how to include the effect of higher dimensional operator into our
study. We finally comment on possible extensions of our work.Comment: 17 pages, 5 figures, figures replaced, minor revision, to appear in
JHE
Linear Confinement for Mesons and Nucleons in AdS/QCD
By using a new parametrization of the dilaton field and including a cubic
term in the bulk scalar potential, we realize linear confinement in both meson
and nucleon sectors within the framework of soft-wall AdS/QCD. At the same time
this model also correctly incorporate chiral symmetry breaking. We compare our
resulting mass spectra with experimental data and find good agreement between
them.Comment: 14 pages, published version in JHE
A Matrix Model for Baryons and Nuclear Forces
We propose a new matrix model describing multi-baryon systems. We derive the
action from open string theory on the wrapped baryon vertex D-branes embedded
in the D4-D8 model of large N holographic QCD. The positions of k baryons are
unified into k x k matrices, with spin/isospin of the baryons encoded in a set
of k-vectors. Holographic baryons are known to be very small in the large 't
Hooft coupling limit, and our model offers a better systematic approach to
dynamics of such baryons at short distances. We compute energetics and spectra
(k=1), and also short-distance nuclear force (k=2). In particular, we obtain a
new size of the holographic baryon and find a precise form of the repulsive
core of nucleons. This matrix model complements the instanton soliton picture
of holographic baryons, whose small size turned out to be well below the
natural length scale of the approximation involved there. Our results show
that, nevertheless, the basic properties of holographic baryons obtained there
are robust under stringy corrections within a few percents.Comment: 30 pages. v3: more comments added, published versio
A Generalised Fractional Differencing Bootstrap for Long Memory Processes
A bootstrap methodology, first proposed in a restricted form by Kapetanios and Papailias (2011), suitable for use with stationary and nonstationary fractionally integrated time series is further developed in this paper. The resampling algorithm involves estimating the degree of fractional integration, applying the fractional differencing operator, resampling the resulting approximation to the underlying short memory series and, finally, cumulating to obtain a resample of the original fractionally integrated process. While a similar approach based on differencing has been independently proposed in the literature for stationary fractionally integrated processes using the sieve bootstrap by Poskitt, Grose and Martin (2015), we extend it to allow for general bootstrap schemes including blockwise bootstraps. Further, we show that it can also be validly used for nonstationary fractionally integrated processes. We establish asymptotic validity results for the general method and provide simulation evidence which highlights a number of favourable aspects of its finite sample performance, relative to other commonly used bootstrap methods
Investigating poultry trade patterns to guide avian influenza surveillance and control: a case study in Vietnam
Live bird markets are often the focus of surveillance activities monitoring avian influenza viruses (AIV) circulating in poultry. However, in order to ensure a high sensitivity of virus detection and effectiveness of management actions, poultry management practices features influencing AIV dynamics need to be accounted for in the design of surveillance programmes. In order to address this knowledge gap, a cross-sectional survey was conducted through interviews with 791 traders in 18 Vietnamese live bird markets. Markets greatly differed according to the sources from which poultry was obtained, and their connections to other markets through the movements of their traders. These features, which could be informed based on indicators that are easy to measure, suggest that markets could be used as sentinels for monitoring virus strains circulating in specific segments of the poultry production sector. AIV spread within markets was modelled. Due to the high turn-over of poultry, viral amplification was likely to be minimal in most of the largest markets. However, due to the large number of birds being introduced each day, and challenges related to cleaning and disinfection, environmental accumulation of viruses at markets may take place, posing a threat to the poultry production sector and to public health
Роль совершенствования бухгалтерского учета в управлении производственными запасами
Целью проведения исследования является обоснование направлений повышения эффективности использования материальных производственных запасов на предприятии в условиях рыночной экономики
Latent tuberculosis infection screening and treatment in congregate settings (TB FREE COREA): protocol for a prospective observational study in Korea
IntroductionSouth Korea regards tuberculosis (TB) incidence in congregate settings as a serious problem. To this end, systematic latent TB infection (LTBI) diagnosis and treatment were provided to approximately 1.2 million individuals in high-risk congregate settings.Methods and analysisWe designed a prospective cohort study of individuals tested for LTBI, based on the data collected on all persons screened for LTBI as part of the 2017 congregate settings programme in South Korea. Four types of databases are kept: LTBI screening database (personal information and LTBI test results), national health information (NHI) database (socio-demographic data and comorbidities), public healthcare information system (PHIS) database, and the Korean national TB surveillance system database (TB outcomes). Information regarding LTBI treatment at private hospitals and public health centres is collected from NHI and PHIS databases, respectively. The screening data are cleaned, duplicates are removed, and, where appropriate, re-coded to analyse specific exposures and outcomes. The primary objective is to compare the number of active TB cases prevented within 2 years between participants undergoing treatment and not undergoing treatment in the LTBI screening programme in congregate settings. Cascade of care for LTBI diagnosis and treatment will be evaluated among those with a positive LTBI test result. A Cox proportional hazards model will be applied to determine the risk factors for developing active TB.Ethics and disseminationThe protocol is approved by the institutional review boards of Incheon St. Mary’s Hospital, the Catholic University of Korea. Study results will be disseminated through peer-reviewed journals and conference presentations.Trial registration numberKCT000390
Traffic-related pollution and asthma prevalence in children. Quantification of associations with nitrogen dioxide.
Ambient nitrogen dioxide is a widely available measure of traffic-related air pollution and is inconsistently associated with the prevalence of asthma symptoms in children. The use of this relationship to evaluate the health impact of policies affecting traffic management and traffic emissions is limited by the lack of a concentration-response function based on systematic review and meta-analysis of relevant studies. Using systematic methods, we identified papers containing quantitative estimates for nitrogen dioxide and the 12 month period prevalence of asthma symptoms in children in which the exposure contrast was within-community and dominated by traffic pollution. One estimate was selected from each study according to an a priori algorithm. Odds ratios were standardised to 10 μg/m(3) and summary estimates were obtained using random- and fixed-effects estimates. Eighteen studies were identified. Concentrations of nitrogen dioxide were estimated for the home address (12) and/or school (8) using a range of methods; land use regression (6), study monitors (6), dispersion modelling (4) and interpolation (2). Fourteen studies showed positive associations but only two associations were statistically significant at the 5 % level. There was moderate heterogeneity (I(2) = 32.8 %) and the random-effects estimate for the odds ratio was 1.06 (95 % CI 1.00 to 1.11). There was no evidence of small study bias. Individual studies tended to have only weak positive associations between nitrogen dioxide and asthma prevalence but the summary estimate bordered on statistical significance at the 5 % level. Although small, the potential impact on asthma prevalence could be considerable because of the high level of baseline prevalence in many cities. Whether the association is causal or indicates the effects of a correlated pollutant or other confounders, the estimate obtained by the meta-analysis would be appropriate for estimating impacts of traffic pollution on asthma prevalence
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