5,377 research outputs found
The analysis of barriers to bim implementation for industrialized building construction: a China study
The emerging Building Information Modeling (BIM) can better promote the development of building industrialization, with data integration between information-rich building models and business processes. However, the practical implementation of BIM still faces barriers. Existing studies have discussed these barriers extensively, but the research on the barriers to the implementation of BIM amid building industrialization in China is inadequate. In this study, 23 barriers were identified through literature review. A questionnaire survey approach was used to collect data from various parties. Factor analysis methods were used to process and rank barrier factors for BIM applications in the context of industrialized building. Based on the analysis of each factor, analytic hierarchy process was adopted to identify the key barriers to the implementation of BIM for industrialized building construction. The study concluded that the main barriers for BIM implementation for industrialized building were capital-related factors and the lack of support from owners. This study proposes that in addition to governmental policy support for BIM and multi-stakeholder engagement, companies should also organize experts to effectively evaluate the risks of applying BIM. Overall, this study provides suggestions on construction organizational transformations in the roadmap of moving towards digital-driven building industrialization
Improved taxol production in Nodulisporium sylviforme derived from inactivated protoplast fusion
Inactivated protoplast fusion by UV irradiation and UV+LiCl mutation was conducted using Nodulisporium sylviforme strain UV40-19 and UL50-6 to breed a high taxol-producing fungus. Qualitative and quantitative analysis of taxol production was confirmed using thin-layer chromatography, high performance liquid chromatography and mass spectrometry. The protoplasts of UV40-19 and UL50-6 were fully inactivated by heating at 54°C for 5 min and by UV irradiation (30 w UV light and vertical distance 30 cm) for 85 s. The highest fusion rate (14.31 ± 1.13%) between UV40-19 and UL50-6 was obtained under the conditions of 35% PEG, 90 s fusion time and the addition of 0.01 mol/l CaCl2. One high taxol production strain HDF-68 was obtained. The taxol production was up to 468.62 ± 37.49 μg/l, which was increased by 24.51 and 19.35% compared with the parental strain UV40-19 and UL50-6, respectively. This study provided a good basis for the application of this technique to the breeding of the strains with high taxol output.Key words: Taxol, endophytic fungi, protoplast preparation, protoplast fusion
Skyrmion-skyrmion and skyrmion-edge repulsions in skyrmion-based racetrack memory
Magnetic skyrmions are promising for building next-generation magnetic
memories and spintronic devices due to their stability, small size and the
extremely low currents needed to move them. In particular, skyrmion-based
racetrack memory is attractive for information technology, where skyrmions are
used to store information as data bits instead of traditional domain walls.
Here we numerically demonstrate the impacts of skyrmion-skyrmion and
skyrmion-edge repulsions on the feasibility of skyrmion-based racetrack memory.
The reliable and practicable spacing between consecutive skyrmionic bits on the
racetrack as well as the ability to adjust it are investigated. Clogging of
skyrmionic bits is found at the end of the racetrack, leading to the reduction
of skyrmion size. Further, we demonstrate an effective and simple method to
avoid the clogging of skyrmionic bits, which ensures the elimination of
skyrmionic bits beyond the reading element. Our results give guidance for the
design and development of future skyrmion-based racetrack memory.Comment: 15 pages, 6 figure
Fermi resonance-algebraic model for molecular vibrational spectra
A Fermi resonance-algebraic model is proposed for molecular vibrations, where
a U(2) algebra is used for describing the vibrations of each bond, and Fermi
resonances between stretching and bending modes are taken into account. The
model for a bent molecule XY_2 and a molecule XY_3 is successfully applied to
fit the recently observed vibrational spectrum of the water molecule and arsine
(AsH_3), respectively, and results are compared with those of other models.
Calculations show that algebraic approaches can be used as an effective method
for describing molecular vibrations with small standard deviations
Period halving of Persistent Currents in Mesoscopic Mobius ladders
We investigate the period halving of persistent currents(PCs) of
non-interacting electrons in isolated mesoscopic M\"{o}bius ladders without
disorder, pierced by Aharonov-Bhom flux. The mechanisms of the period halving
effect depend on the parity of the number of electrons as well as on the
interchain hopping. Although the data of PCs in mesoscopic systems are
sample-specific, some simple rules are found in the canonical ensemble average,
such as all the odd harmonics of the PCs disappear, and the signals of even
harmonics are non-negative. {PACS number(s): 73.23.Ra, 73.23.-b, 68.65.-k}Comment: 6 Pages with 3 EPS figure
Upregulation of Phosphodiesterase type 5 in the Hyperplastic Prostate
Both erectile dysfunction (ED) and lower urinary tract symptoms (LUTS)/benign prostatic hyperplasia (BPH) are common in the aging male. Numerous clinical trials have demonstrated the efficacy and safety of phosphodiesterase type 5 inhibitors (PDE5-Is) for treating LUTS/BPH with/without ED. However, the influence of BPH on prostatic PDE5 expression has never been studied. A testosterone-induced rat model of BPH was developed and human hyperplastic prostate specimens were harvested during cystoprostatectomy. PDE5, nNOS, eNOS and α1-adrenoreceptor subtypes (α1aARs, α1bARs and α1dARs) were determined with real-time RT-PCR for rat tissues whilst PDE5 and α1-adrenoreceptor subtypes were determined in human samples. PDE5 was further analyzed with Western-blot and histological examination. Serum testosterone was measured with ELISA. The rat BPH model was validated as having a significantly enlarged prostate. PDE5 localized mainly in fibromuscular stroma in prostate. Our data showed a significant and previously undocumented upregulation of PDE5 in both rat and human BPH, along with increased expression of nNOS and α1d ARs for rat tissues and α1a ARs for human BPH. The upregulation of PDE5 in the hyperplastic prostate could explain the mechanism and contribute to the high effectiveness of PDE5-Is for treating LUTS/BPH. Fibromuscular stroma could be the main target for PDE5-Is within prostate
Quantum spin Hall effect and spin-charge separation in a kagome lattice
A two-dimensional kagome lattice is theoretically investigated within a
simple tight-binding model, which includes the nearest neighbor hopping term
and the intrinsic spin-orbit interaction between the next nearest neighbors. By
using the topological winding properties of the spin-edge states on the
complex-energy Riemann surface, the spin Hall conductance is obtained to be
quantized as () in insulating phases. This result keeps
consistent with the numerical linear-response calculation and the
\textbf{Z} topological invariance analysis. When the sample boundaries
are connected in twist, by which two defects with flux are introduced, we
obtain the spin-charge separated solitons at 1/3 (or 2/3) filling.Comment: 13 NJP pages, 7 figure
Effect of the Inhomogeneity of Ice Crystals on Retrieving Ice Cloud Optical Thickness and Effective Particle Size
Spherical or spheroidal air bubbles are generally trapped in the formation of rapidly growing ice crystals. In this study the single-scattering properties of inhomogeneous ice crystals containing air bubbles are investigated. Specifically, a computational model based on an improved geometric-optics method (IGOM) has been developed to simulate the scattering of light by randomly oriented hexagonal ice crystals containing spherical or spheroidal air bubbles. A combination of the ray-tracing technique and the Monte Carlo method is used. The effect of the air bubbles within ice crystals is to smooth the phase functions, diminish the 22deg and 46deg halo peaks, and substantially reduce the backscatter relative to bubble-free particles. These features vary with the number, sizes, locations and shapes of the air bubbles within ice crystals. Moreover, the asymmetry factors of inhomogeneous ice crystals decrease as the volume of air bubbles increases. Cloud reflectance lookup tables were generated at wavelengths 0.65 m and 2.13 m with different air-bubble conditions to examine the impact of the bubbles on retrieving ice cloud optical thickness and effective particle size. The reflectances simulated for inhomogeneous ice crystals are slightly larger than those computed for homogenous ice crystals at a wavelength of 0.65 microns. Thus, the retrieved cloud optical thicknesses are reduced by employing inhomogeneous ice cloud models. At a wavelength of 2.13 microns, including air bubbles in ice cloud models may also increase the reflectance. This effect implies that the retrieved effective particle sizes for inhomogeneous ice crystals are larger than those retrieved for homogeneous ice crystals, particularly, in the case of large air bubbles
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