524 research outputs found
Tailoring a nanofiber for enhanced photon emission and coupling efficiency from single quantum emitters
We present a novel approach to enhance the spontaneous emission rate of
single quantum emitters in an optical nanofiber-based cavity by introducing a
narrow air-filled groove into the cavity. Our results show that the Purcell
factor for single quantum emitters located inside the groove of the
nanofiber-based cavity can be at least six times greater than that for such an
emitter on the fiber surface when using an optimized cavity mode and groove
width. Moreover, the coupling efficiency of single quantum emitters into the
guided mode of this nanofiber-based cavity can reach up to 80 with
only 35 cavity-grating periods. This new system has the potential to act as an
all-fiber platform to realize efficient coupling of photons from single
emitters into an optical fiber for quantum information applications
Optical nanofiber-based cavity induced by periodic air-nanohole arrays
We experimentally realized an optical nanofiber-based cavity by combining a
1-D photonic crystal and Bragg grating structures. The cavity morphology
comprises a periodic, triplex air-cube introduced at the waist of the
nanofiber. The cavity has been theoretically characterized using FDTD
simulations to obtain the reflection and transmission spectra. We have also
experimentally measured the transmission spectra and a Q-factor of ~784(87) for
a very short periodic structure has been observed. The structure provides
strong confinement of the cavity field and its potential for optical network
integration makes it an ideal candidate for use in nanophotonic and quantum
information systems
Telecom-wavelength spectra of a Rydberg state in a hot vapor
We study telecom-wavelength spectra of a Rydberg state in an atomic vapor
with a three-photon excitation scheme. Two lasers of 780 nm and 776 nm are used
to pump Rubidium-85 atoms in a vapor cell to the state,
from which a probe beam of 1292 nm in the O-band telecommunication wavelength
drives a transition to the Rydberg state. We investigate
the probe spectra over the power of pump lasers. The simulation based on a
4-level theoretical model captures the main features of the experimental
results. This spectroscopic study paves the way for future experiments of
making a direct link between fiber optics and radio transmission via Rydberg
atoms.Comment: 5 pages and 4 figure
Preface: The Integration of Books, Information and Archives against the Background of Information Technology
Projectional Coderivatives and Calculus Rules
This paper is devoted to the study of a newly introduced tool, projectional
coderivatives and the corresponding calculus rules in finite dimensions. We
show that when the restricted set has some nice properties, more specifically,
is a smooth manifold, the projectional coderivative can be refined as a
fixed-point expression. We will also improve the generalized Mordukhovich
criterion to give a complete characterization of the relative Lipschitz-like
property under such a setting. Chain rules and sum rules are obtained to
facilitate the application of the tool to a wider range of problems
Supply Chain Joint Inventory Management and Cost Optimization Based on Ant Colony Algorithm and Fuzzy Model
With the advancement of the marketization process, inventory management has transformed from a single backup protection function to an essential function for enterprises, which helps to survive and develop. Inventory control in supply chain management is the important content of supply chain management. The new management mode makes inventory management present many new characteristics and problems compared with traditional inventory management. From the view of system theory and integration theory, it is imperative to re-examine the problem of inventory control, put forward new inventory management strategies adapted to integrated supply chain management, and improve the integration of the whole supply chain, which can enhance the agility and market response speed of enterprises. Based on the in-depth study of the joint inventory management model, this paper analyzed the current situation of the joint inventory management to optimize the inventory. In view of the achievements and shortcomings of the current research, a more systematic and improved optimization model of the supply chain inventory was proposed by using the basic ideas of ant colony algorithm and fuzzy model
Adenoma Detection Rate in Asymptomatic Patients with Positive Fecal Immunochemical Tests
Background and Aims
The adenoma detection rate (ADR) is a powerful measure of screening colonoscopy quality. Patients who undergo colonoscopy for the evaluation of a positive fecal immunochemical test (FIT) have increased prevalence of colorectal neoplasia, but it is not known whether separate quality benchmarks are required. The aim of this study was to compare the conventional ADR to the ADR of colonoscopies performed for the evaluation of positive FIT, in asymptomatic average-risk patients.
Methods
Patients ≥ 50 years old who underwent colonoscopy for the evaluation of a positive FIT between January 1, 2013, and July 31, 2014, at a tertiary Veterans Affairs Medical Center were identified. FIT performed for any indication other than average-risk screening was excluded. The comparison group included average-risk patients ≥ 50 years old undergoing screening colonoscopy during the same time frame. The two groups were compared for ADR, advanced neoplasm [adenoma ≥ 10 mm, tubulovillous, high-grade dysplasia, CRC, sessile serrated polyp (SSP) ≥ 10 mm], CRC, and SSP detection after propensity score adjustment using a logistic regression model adjusted for endoscopist.
Results
There were 207 patients in the FIT group and 601 in the screening colonoscopy comparison group. After propensity score adjustment, ADR (72.9 vs. 50.0%, p = 0.003), number of adenomas per colonoscopy (3.3 ± 3.6 vs. 1.4 ± 2.3, p = 0.033), and advanced neoplasm detection rate (32.4 vs. 11.0%, p < 0.0001) were significantly higher in the FIT group. There were no significant differences in the number of CRC and the SSP detection rate.
Conclusions
In this cohort of average-risk Veterans, the ADR of colonoscopies performed for the evaluation of a positive FIT was higher than the ADR of screening colonoscopies. Patients with a positive FIT also had significantly more adenomas per colonoscopy and advanced neoplasms. These findings suggest that the quality of colonoscopies performed for a positive FIT is insufficiently assessed by the conventional ADR and requires additional quality metrics
Corporate Credit Rating: A Survey
Corporate credit rating (CCR) plays a very important role in the process of
contemporary economic and social development. How to use credit rating methods
for enterprises has always been a problem worthy of discussion. Through reading
and studying the relevant literature at home and abroad, this paper makes a
systematic survey of CCR. This paper combs the context of the development of
CCR methods from the three levels: statistical models, machine learning models
and neural network models, summarizes the common databases of CCR, and deeply
compares the advantages and disadvantages of the models. Finally, this paper
summarizes the problems existing in the current research and prospects the
future of CCR. Compared with the existing review of CCR, this paper expounds
and analyzes the progress of neural network model in this field in recent
years.Comment: 11 page
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