3,372 research outputs found
Seasonal occurrence and species specificity of fishy and musty odor in Huajiang Reservoir in winter, China
AbstractThis paper describes the results of measurements from one year period on the existence of fishy and musty odor in drinking water at low temperatures (1–2°C) in Baotou, China, using an open-loop stripping analysis (OLSA) systems and Gas chromatography spectrometry (GC). The main results show that it is micro-contaminated water body of the raw water in Huajiang Reservoir. The average phytoplankton abundance was 2.06×107L−1, Cyanobacteria counts were at 2.0×106L−1 and the dominate family of the algae are Chlorophyta, Cryptophyta, and Bacillariophyta. Experimental results indicated that under the ice whose thickness was 0.55m, the photosynthetically active radiation (PAR) of the surface varied from 70 to 636Wm−2 from November to March of next year. The average surface PAR was 114.8Wm−2, and the lowest value was 70.57Wm−2 (in December) and the average bottom PAR was 19.04Wm−2, and the lowest value was 3.84Wm−2 (in December). The surface PAR, bottom PAR, eutrophic conditions in ice-covered Huajiang reservoir satisfied the growth and MIB/geosmin production of Cyanobacteria algae in winter. The 2-methyl-isoborneol (MIB) concentration ranged from 29ngL−1 to 102ngL−1. The concentration of trans-1,10-dimethyl-trans-9-decalol (geosmin) ranges from 20ngL−1 to 65ngL−1 and it is 2 to 5 times of the odor threshold concentrations (OTC). The correlations between MIB/geosmin and nitrogen are 0.63–0.37. Eutrophication is the most important factor influencing synthesis of taste and odors, but not temperature. Using bypassing pipe pumping Yellow River water directly to the Water treatment plant (WTP) is an efficient way about T&O compounds׳ control in drinking water of Baotou city in winter
Localized States and Quantum Spin Hall Effect in Si-Doped InAs/GaSb Quantum Wells
We study localized in-gap states and quantum spin Hall effect in Si-doped
InAs/GaSb quantum wells. We propose a model describing donor and/or acceptor
impurities to describe Si dopants. This model shows in-gap bound states and
wide conductance plateau with the quantized value in light dopant
concentration, consistent with recent experiments by Du et al. We predict a
conductance dip structure due to backward scattering in the region where the
localization length is comparable with the sample width but much
smaller than the sample length .Comment: 4+pages main text including 4 figures, supplementary materials with 3
figures are include
Y Chromosomes of 40% Chinese Are Descendants of Three Neolithic Super-grandfathers
Demographic change of human populations is one of the central questions for
delving into the past of human beings. To identify major population expansions
related to male lineages, we sequenced 78 East Asian Y chromosomes at 3.9 Mbp
of the non-recombining region (NRY), discovered >4,000 new SNPs, and identified
many new clades. The relative divergence dates can be estimated much more
precisely using molecular clock. We found that all the Paleolithic divergences
were binary; however, three strong star-like Neolithic expansions at ~6 kya
(thousand years ago) (assuming a constant substitution rate of 1e-9/bp/year)
indicates that ~40% of modern Chinese are patrilineal descendants of only three
super-grandfathers at that time. This observation suggests that the main
patrilineal expansion in China occurred in the Neolithic Era and might be
related to the development of agriculture.Comment: 29 pages of article text including 1 article figure, 9 pages of SI
text, and 2 SI figures. 5 SI tables are in a separate ancillary fil
A Fast and Scalable Authentication Scheme in IoT for Smart Living
Numerous resource-limited smart objects (SOs) such as sensors and actuators
have been widely deployed in smart environments, opening new attack surfaces to
intruders. The severe security flaw discourages the adoption of the Internet of
things in smart living. In this paper, we leverage fog computing and
microservice to push certificate authority (CA) functions to the proximity of
data sources. Through which, we can minimize attack surfaces and authentication
latency, and result in a fast and scalable scheme in authenticating a large
volume of resource-limited devices. Then, we design lightweight protocols to
implement the scheme, where both a high level of security and low computation
workloads on SO (no bilinear pairing requirement on the client-side) is
accomplished. Evaluations demonstrate the efficiency and effectiveness of our
scheme in handling authentication and registration for a large number of nodes,
meanwhile protecting them against various threats to smart living. Finally, we
showcase the success of computing intelligence movement towards data sources in
handling complicated services.Comment: 15 pages, 7 figures, 3 tables, to appear in FGC
The epitope of the VP1 protein of porcine parvovirus
Porcine parvovirus (PPV) is the major causative agent in a syndrome of reproductive failure in swine. Much has been learned about the structure and function of PPV in recent years, but nothing is known about the epitopes of the structural protein VP1, which is an important antigen of PPV. In this study, the monoclonal antibody C4 against VP1 of PPV was prepared and was used to biopan a 12-mer phage peptide library three times. The selected phage clones were identified by ELISA and then sequencing. The amino acid sequences detected by phage display were analyzed, and a mimic immuno-dominant epitope was identified. The epitope of VP1 is located in the N-terminal and contains the role amino acid sequence R-K-R. Immunization of mice indicated that the phage-displayed peptide induces antibodies against PPV. This study shows that peptide mimotopes have potential as alternatives to the complex antigens currently used for diagnosis of PPV infection or for development of vaccines
1-[9-Ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]ethanone
In the title compound, C24H21NO2, the pendant benzene ring is inclined at a dihedral angle of 86.66 (18)° with respect to the adjacent aromatic ring of the carbozole unit. In the crystal structure, symmetry-related molecules are linked via C—H⋯O and C—H⋯π interactions
Phase diagrams on composition-spread FeTeSe films
FeTeSe, an archetypical iron-based high-temperature
superconductor with a simple structure but rich physical properties, has
attracted lots of attention because the two end compositions, Se content and 1, exhibit antiferromagnetism and nematicity, respectively, making it an
ideal candidate for studying their interactions with superconductivity.
However, what is clearly lacking to date is a complete phase diagram of
FeTeSe as functions of its chemical compositions since phase
separation usually occurs from to 0.9 in bulk crystals. Moreover,
fine control of its composition is experimentally challenging because both Te
and Se are volatile elements. Here we establish a complete phase diagram of
FeTeSe, achieved by high-throughput film synthesis and
characterization techniques. An advanced combinatorial synthesis process
enables us to fabricate an epitaxial composition-spread FeTeSe
film encompassing the entire Se content from 0 to 1 on a single piece of
CaF substrate. The micro-region composition analysis and X-ray diffraction
show a successful continuous tuning of chemical compositions and lattice
parameters, respectively. The micro-scale pattern technique allows the mapping
of electrical transport properties as a function of relative Se content with an
unprecedented resolution of 0.0074. Combining with the spin patterns in
literature, we build a detailed phase diagram that can unify the electronic and
magnetic properties of FeTeSe. Our composition-spread
FeTeSe films, overcoming the challenges of phase separation and
precise control of chemical compositions, provide an ideal platform for
studying the relationship between superconductivity and magnetism.Comment: 13 pages,5 figures and Supplementary Material 3 pages,3 figure
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