3,789 research outputs found
Observation of fractional quantum Hall effect in an InAs quantum well
The two-dimensional electron system in an InAs quantum well has emerged as a
prime candidate for hosting exotic quasi-particles with non-Abelian statistics
such as Majorana fermions and parafermions. To attain its full promise,
however, the electron system has to be clean enough to exhibit
electron-electron interaction phenomena. Here we report the observation of
fractional quantum Hall effect in a very low disorder InAs quantum well with a
well-width of 24 nm, containing a two-dimensional electron system with a
density cm and low-temperature mobility cm/Vs. At a temperature of mK and T, we
observe a deep minimum in the longitudinal resistance, accompanied by a nearly
quantized Hall plateau at Landau level filling factor
Analysis of Lean Manufacturing: A Cost Saving Approach in Garments Production Unit
Sewing process is one of the most important stages in labor intensive ready-made clothing enterprises. Quality faults occurring during this process adversely affect the product quality and product efficiency, and also increase the production cost. The aim of this study is to investigate whether the knitwear production process is under control in a knitwear production enterprise and to detect the processes with highest rates of sewing faults in sewing department and finally to make suggestions for improving the quality control. Among the Statistical Process Control methods; control list, product control chart were used in the study. “Product control chart” was used to test whether the production process is controlled in the enterprise. Furthermore, the statistical methods were employed to determine the issues that need to be done in the improvement efforts and to detect the relations between the process groups supposedly effective on faults occurring in knitwear production and the amount of faults. Also, the processes with highest amounts of sewing faults and the effects of these processes on fault rates were investigated. As a result, it was concluded that the production process was statistically not under control in the ready-made clothing enterprise. In addition, this study demonstrated that the investigation of each process group by drawing their product control charts would make significant contributions to foresee the results and prepare more effective the improvement plans.
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Serum Lectin-Like Oxidized-Low Density Lipoprotein Receptor-1 and Adiponectin Levels Are Associated With Coronary Artery Disease Accompanied With Metabolic Syndrome
Background: Coronary artery disease (CAD) is a major public health problem for developed and developing countries and is the single leading cause of death worldwide. Objectives: There is very few evidence regarding changes of both serum Lectin-like oxidized-low density lipoprotein receptor-1 (LOX-1) and adiponectin in patients with CAD accompanied with metabolic syndrome (MS). Here we aimed to evaluate serum levels of LOX-1 and adiponectin in patients with CAD accompanied with MS. Patients and Methods: Thirty patients with coronary artery disease without metabolic syndrome, 30 patients with coronary artery disease and metabolic syndrome, 30 ones with metabolic syndrome and 30 healthy subjects were enrolled. For all subjects, a questionnaire was filled to collect data, and peripheral blood samples were collected aseptically from the antecubital vein to measure serum Lectin-like oxidized-low density lipoprotein receptor-1 and adiponectin levels by enzyme-linked immunosorbent assay. Results: Serum LOX-1 level was highest in CAD + MS group; the difference between control and disease groups was statistically significant (P < 0.001). Adiponectin level had the lowest value in CAD + MS group; the difference between control and disease groups was statistically significant (P < 0.05). No significant differences were observed in serum Lectin-like oxidized-low density lipoprotein receptor-1and adiponectin in patients with different ages and gender. Serum LOX-1 level was changed negatively and linearly (R2 = 0.721) correlated with adiponectin level in different groups. Conclusions: Patient with CAD and MS had higher risk than those with only CAD because of lipid and glucose metabolism abnormalities. Combination measurements of serum LOX-1 and adiponectin levels may be helpful to evaluate the severity of CAD together with MS
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Experimental study on Shear capacity of cementitious composite RPC Beams using high strength steel
Reactive Powder Concrete (RPC) is a special concrete where the microstructure is optimized by precise gradation of all particles in the mix to yield maximum density. Therefore, Reactive Powder Concrete exhibits ultra-high strength and durability. The high strength reinforcement (HSR) has high strength and good plastic deformation properties. The combination of RPC and high strength reinforcement can fully exploit their respective advantages. At present, there is little research on shear capacity of HSR reinforced RPC concrete beams, neither are design guidelines for this type of structure. Therefore, it is imperative to make detailed investigations on the shear capacity of this type of concrete. In this paper, thirty-two full scale shear tests of high strength steel reinforced RPC beams were carried out. The parameters affecting the shear capacity of this type of structures were studied, the major failure modes of this type structure due to shear are identified
Primordial Earth mantle heterogeneity caused by the Moon-forming giant impact
The giant impact hypothesis for Moon formation successfully explains the dynamic properties of the Earth–Moon system but remains challenged by the similarity of isotopic fingerprints of the terrestrial and lunar mantles. Moreover, recent geochemical evidence suggests that the Earth's mantle preserves ancient (or "primordial") heterogeneity that pre-dates the Moon-forming giant impact. Using a new hydrodynamical method, we here show that Moon-forming giant impacts lead to a stratified starting condition for the evolution of the terrestrial mantle. The upper layer of the Earth is compositionally similar to the disk, out of which the Moon evolves, whereas the lower layer preserves proto-Earth characteristics. As long as this predicted compositional stratification can at least partially be preserved over the subsequent billions of years of Earth mantle convection, a compositional similarity between the Moon and the accessible Earth's mantle is a natural outcome of realistic and high-probability Moon-forming impact scenarios. The preservation of primordial heterogeneity in the modern Earth not only reconciles geochemical constraints but is also consistent with recent geophysical observations. Furthermore, for significant preservation of a proto-Earth reservoir, the bulk major-element composition of the Earth–Moon system may be systematically shifted toward chondritic values
Microjoule-level mid-infrared femtosecond pulse generation in hollow-core fibres
We demonstrate a fibre-based approach that generates mid-infrared femtosecond
pulses in the 3-4 {\mu}m spectral region with microjoule-level single pulse
energy. This is realised in a piece of gas-filled antiresonant hollow-core
fibre that is pumped by a two-micron light source. A rapid variation of the
dispersion near a structural resonance of the fibre creates a phase-matching
point in the mid-infrared, which mediates the frequency-down conversion. We
generate femtosecond pulses centred at 3.16 {\mu}m wavelength with the pulse
energy of more than 1 {\mu}J, achieving the conversion efficiency as high as
9.4%. The wavelength of the radiation is determined solely by the dielectric
wall thickness of the cladding elements, while the yield is subject to other
experimental parameters. This, combined with high power-handling capability of
hollow-core fibres, makes it possible to power scale the mid-infrared output by
either increasing the pulse energy or repetition rate of the pump. The
technique presents a new pathway to build an all-fibre-based mid-infrared
supercontinuum source, which promises to be a powerful new tool for ultrahigh
sensitivity molecular spectroscopy
Independent association of low serum 25-hydroxyvitamin d and 1,25-dihydroxyvitamin d levels with allcause and cardiovascular mortality. Arch Intern Med.
Background: In cross-sectional studies, low serum levels of 25-hydroxyvitamin D are associated with higher prevalence of cardiovascular risk factors and disease. This study aimed to determine whether endogenous 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D levels are related to all-cause and cardiovascular mortality
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