1,788 research outputs found
Broadband enhancement of light harvesting in luminescent solar concentrator
Luminescent solar concentrator (LSC) can absorb large-area incident sunlight,
then emit luminescence with high quantum efficiency, which finally be collected
by a small photovoltaic (PV) system. The light-harvesting area of the PV system
is much smaller than that of the LSC system, potentially improving the
efficiency and reducing the cost of solar cells. Here, based on Fermi-golden
rule, we present a theoretical description of the luminescent process in
nanoscale LSCs where the conventional ray-optics model is no longer applicable.
As an example calculated with this new model, we demonstrate that a slot
waveguide consisting of a nanometer-sized low-index slot region sandwiched by
two high-index regions provides a broadband enhancement of light harvesting by
the luminescent centers in the slot region. This is because the slot waveguide
can (1) greatly enhance the spontaneous emission due to the Purcell effect, (2)
dramatically increase the effective absorption cross-section of luminescent
centers, and (3) strongly improve the quantum efficiency of luminescent
centers. It is found that about 80% solar photons can be ultimately converted
to waveguide-coupled luminescent photons even for a low luminescent quantum
efficiency of 0.5. This LSC is potential to construct a tandem structure which
can absorb nearly full-spectrum solar photons, and also may be of special
interest for building integrated nano-PV applications
Experimental Study of Impact of Dock Structures on Water Level in Mountainous Waterway
Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchive
HAZ Phase Transformation and Thermal Damage for Laser Remanufacturing a High-Strength Stainless Steel
It briefly introduced laser remanufacturing, which was an advanced repairing method to refabricate damaged components based on laser forming technologies. The possible factors in determining the performance of the laser remanufacturing FV520B were studied by numerical simulation and experimental methods. First, the results of free dilatometry test showed that the volume effect of phase transformations were corresponding to the transformation temperatures and heating rate of the laser process had remarkable effects on the kinetics of phase transformation. In addition, the evolution of temperature fields of the single-pass and multi-layer laser cladding processes were analyzed by numerical simulation method based on deactivate and reactivate element theory. A combined method of dilatometry and metallography was conducted to reveal the effect of cooling condition and phase transformation on the microstructure of HAZ. The maximum temperature of thermal cycle had a dominating effect on the microstructure, microhardness and phase transformation temperature rather than cooling rate. Thermal cycles had a significant effect on the metallographic transformation and consequently decided the mechanical performance. Microhardness and tensile tests were conducted and the results showed that strength and ductility of laser remanufacturing FV520B were equivalent to that of forgings
Analysis of Adiponectin Gene Polymorphisms in Chinese Population with Systemic Lupus Erythematosus
Systemic lupus erythematosus (SLE) is a prototypic systemic autoimmune disease. Adiponectin is an adipocyte-derived cytokine with anti-inflammatory, antidiabetic, and antiatherogenic properties. No study has reported on the association between adiponectin (ADIPOQ) gene and SLE. Our aim is to investigate the association between single-nucleotide polymorphisms in ADIPOQ gene and SLE. We examined 179 SLE patients and 237 age- and gender-matched controls from Sichuan province in China. Genotypes were determined using polymerase chain reaction-restriction fragment length polymorphism and DNA sequencing. Results show that there was no significant difference in the allele frequencies of rs1501299 (P = .311, OR = 1.17, 95% CI: 0.86–1.59) and rs2241766 (P = .929, OR = 0.99, 95% CI: 0.74–1.33) in ADIPOQ gene between SLE patients and controls. The same results were seen in their genotypes (P < .05). The allele frequencies of rs1501299 and rs2241766 polymorphisms of ADIPOQ may not be associated with SLE risk
Combined analysis of endometrial thickness and pattern in predicting outcome of in vitro fertilization and embryo transfer: a retrospective cohort study
<p>Abstract</p> <p>Objective</p> <p>To evaluate the combined effect of endometrial thickness and pattern on clinical outcome in patients undergoing in vitro fertilization/intracytoplasmic sperm injection and embryo transfer (IVF/ICSI-ET).</p> <p>Methods</p> <p>Cycles of IVF/ICSI-ET conducted between January 2003 and December 2008 at a university-based reproductive center were reviewed retrospectively. Endometrial ultrasonographic characteristics were recorded on the day of hCG administration. In the combined analysis, endometrial thickness groups (group 1: equal or <7 mm; group 2: 7-14 mm; group 3: >14 mm) were subdivided into two endometrial patterns (pattern A: triple-line; pattern B: no-triple line). Clinical pregnancy rate (CPR) and early miscarriage rate in different groups were analyzed.</p> <p>Results</p> <p>A total of 2896 cycles were reviewed. Clinical pregnancy rate (CPR) was 24.4% in group1-A. There were no second trimester pregnancies in group 1-B. Miscarriage rate in group 2-A was significantly lower compared to group 2-B (P < 0.01), although CPR did not show any significant differences between the groups. A no-triple line endometrial pattern with moderate endometrial thickness (7-14 mm) had a detrimental effect on pregnancy outcome, but not the occurrence of pregnancy. In group 3, there was no difference in CPR and miscarriage rates between the two patterns; adequate endometrial thickness (>14 mm) seemed to mitigate the detrimental impact (high miscarriage rate) of pattern B.</p> <p>Conclusion</p> <p>Combined analysis of endometrial thickness and pattern on the day of hCG administration was a better predictor of the outcome of IVF/ICSI-ET and may be more helpful for patient counseling than the separate analyses.</p
3-[(R)-3,3-Dichloro-2-hydroxypropyl]-8-hydroxy-6-methoxy-1H-isochromen-1-one
The title compound, C13H12Cl2O5, is an isocoumarin compound which has been isolated from the ethyl acetate extract of the fermentation broth of actinomycete Streptomyces sp. (V4) from the South China Sea. There are intra- and intermolecular hydrogen bonds and halogen bonds [Cl⋯Cl = 3.434 (2) Å; C—Cl⋯Cl = 121.6°]. The intermolecular O—H⋯O hydrogen bonds link molecules into chains along the b axis
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