Fabrication of a high sensitive Ag-nanoparticle substrate and its application to the detection of toxic substances

Surface Enhanced Raman Scattering (SERS) is typically observed with the substrate in a liquid medium and it has been proposed as a promising technique for detecting low levels of pollutants in liquids. A technique is presented for self-assembly to immobilize Ag nanoparticles (Ag-NPs), with diameters ranging from 100 to 800nm on a solid support. Experimental results have been obtained through experiments using Ag-NPs active substrates to detect Rhodamine 6G (R6G) and crystal violet in the deionized water. Further, the SERS spectrum and Raman spectrum of phoxim were also measured, showing the enhancement in the performance of the active substrate as a result

Enhanced Raman Detection System based on a Hollow-core Fiber Probe design

This paper focus on an enhanced Raman-based detection probe and its performance evaluated. The probe employs a hollow-core fiber design to allow liquid micro-sample to be analyzed. The hollow-core fiber is used both to transmit the light signal used to excite the sample and to collect the Raman scattering signal received from the micro-sample under analysis. In order to maximize the performance of the system, various parameters have been studied experimentally, including the diameter and the height of the liquid sample in the probe. The aim has been optimizing both as a means to enhance the Raman scattering signal received from the liquid sample. As a result, a Raman-based detection probe using a reflector approach was developed and evaluated. This design enabling a greater area for interaction with the sample to be formed and to concentrate the excitation light into it. This then increases the efficiency of the light-liquid interaction and improves the collection efficiently of the forward Raman scattering light signal. With the use of this design, the detected Raman scattering signal was increased by a factor of 103~104 over what otherwise would be achieved. A key feature is that with the use of a hollow-core fiber to collect the liquid sample, only a very small volume is needed, making this well suited to practical applications where limited amounts of material are available e.g. biofluids or high value liquids. The system designed and evaluated thus provides the basis of an effective all-fiber Raman-based detection system, capable of being incorporated into portable analysis equipment for rapid detection and in-the-field use

A Sensitive and Reliable Carbon Monoxide Monitor for Safety-Focused Applications in Coal Mine Using a 2.33-μ\mu m Laser Diode

In this paper, a stable and reliable carbon monoxide (CO) monitoring system with high sensitivity (at sub-ppm level) was designed and demonstrated with particular reference to use in the mining industry, tailoring the design specifically for forecasting spontaneous combustion, a major hazard to miners. An appropriate strong CO absorption line was used to minimize the interferences expected from gases present in ambient air, with several preferred CO absorption lines selected and investigated, therefore choosing a distributed feedback (DFB) laser operating at a wavelength of 2330.18 nm as the excitation source. Through a detailed investigation, a minimum detection limit of ~0.2 ppm and a measurement precision of <50 ppb were achieved with a 1 s averaging time. Further in tests, a long-term continuous monitoring evaluation was carried out, demonstrated the excellent stability and reliability of the developed CO monitor. The results obtained have validated the potential of this design of a CO monitoring system for practical monitoring applications underground to enhance safety in the mining industry

Candidate chiral doublet bands in the odd-odd nucleus 126^{126}Cs

The candidate chiral doublet bands recently observed in $^{126}$Cs have been extended to higher spins, several new linking transitions between the two partner members of the chiral doublet bands are observed, and $\gamma$$-$intensities related to the chiral doublet bands are presented by analyzing the $\gamma$$-$$\gamma$ coincidence data collected earlier at the NORDBALL through the $^{116}$Cd$($$^{14}$N, 4n$)$$^{126}$Cs reaction at a beam energy of 65 MeV. The intraband $B(M1)/B(E2)$ and interband $B(M1)_{in}/B(M1)_{out}$ ratios and the energy staggering parameter, S(I), have been deduced for these doublet bands. The results are found to be consistent with the chiral interpretation for the two structures. Furthermore, the observation of chiral doublet bands in $^{126}$Cs together with those in $^{124}$Cs, $^{128}$Cs, $^{130}$Cs and $^{132}$Cs also indicates that the chiral conditions do not change rapidly with decreasing neutron number in these odd-odd Cesium isotopes

Composite Correlation Quantization for Efficient Multimodal Retrieval

Efficient similarity retrieval from large-scale multimodal database is pervasive in modern search engines and social networks. To support queries across content modalities, the system should enable cross-modal correlation and computation-efficient indexing. While hashing methods have shown great potential in achieving this goal, current attempts generally fail to learn isomorphic hash codes in a seamless scheme, that is, they embed multiple modalities in a continuous isomorphic space and separately threshold embeddings into binary codes, which incurs substantial loss of retrieval accuracy. In this paper, we approach seamless multimodal hashing by proposing a novel Composite Correlation Quantization (CCQ) model. Specifically, CCQ jointly finds correlation-maximal mappings that transform different modalities into isomorphic latent space, and learns composite quantizers that convert the isomorphic latent features into compact binary codes. An optimization framework is devised to preserve both intra-modal similarity and inter-modal correlation through minimizing both reconstruction and quantization errors, which can be trained from both paired and partially paired data in linear time. A comprehensive set of experiments clearly show the superior effectiveness and efficiency of CCQ against the state of the art hashing methods for both unimodal and cross-modal retrieval