Sensitive and easily recyclable plasmonic SERS substrate based on Ag nanowires in mesoporous silica

Raman spectra were obtained by a Renishaw inVia with a laser of 532 nm and 0.5% strength, samples were arranged on the silica plate. X-ray diffraction (XRD) patterns of the samples were recorded on a Rigaku D/MAX- 2550 diffractometer using Cu Kα radiation of wavelength 1.5406 Å, typically run at a voltage of 40 kV and current of 100 mA. UV-visible absorbance spectra were achieved for the dry pressed disk samples using a Scan UV-Vis spectrophotometer (Varian, Cary 500) equipped with an integrating sphere assembly, using BaSO4 as a reflectance sample. Transmission electron microscopy (TEM) images were collected on a JEOL JEM 2010F, electron microscope operated at an acceleration voltage of 200 kV. By utilizing the Barrett−Joyner−Halenda (BJH) model, the pore volumes and pore size distributions were got from the adsorption branches of isotherms

Side-Scan Sonar Image Segmentation Based on Multi-Channel CNN for AUV Navigation

The AUV (Autonomous Underwater Vehicle) navigation process relies on the interaction of a variety of sensors. The side-scan sonar can collect underwater images and obtain semantic underwater environment information after processing, which will help improve the ability of AUV autonomous navigation. However, there is no practical method to utilize the semantic information of side scan sonar image. A new convolutional neural network model is proposed to solve this problem in this paper. The model is a standard codec structure, which extracts multi-channel features from the input image and then fuses them to reduce parameters and strengthen the weight of feature channels. Then, a larger convolution kernel is used to extract the features of large-scale sonar images more effectively. Finally, a parallel compensation link with a small-scale convolution kernel is added and spliced with features extracted from a large convolution kernel in the decoding part to obtain features of different scales. We use this model to conduct experiments on self-collected sonar data sets, which were uploaded on github. The experimental results show that ACC and MIoU reach 0.87 and 0.71, better than other classical small-order semantic segmentation networks. Furthermore, the 347.52 g FOLP and the number of parameters around 13 m also ensure the computing speed and portability of the network. The result can extract the semantic information of the side-scan sonar image and assist with AUV autonomous navigation and mapping

Fast Quantification of Phosphorus in Crude Soybean Oil by Near-Infrared Spectroscopy

The existing methods for the determination of phosphorus content are unable to regulate the addition of acid and base in the refining process of crude soybean oil through real-time monitoring. Therefore, a novel rapid method for determining the phosphorus content of crude soybean oil based on near-infrared spectroscopy was proposed in this study. It was found that standard normal variate transformation was more effective than two other spectral preprocessing methods evaluated for denoising the spectral data indicative of the phosphorus content in soybean crude oil. The characteristic absorption band of phosphorus was optimized by synergy interval partial least squares (SiPLS). A back propagation (BP) neural network prediction model of the phosphorus content in crude soybean oil was established with learning efficiency of 0.005 and 108 training cycles. The determination coefficient (R2), root mean square error (RMSE) and relative standard deviation (RSD) for the correction set were 0.979 7, 0.859 3 and 1.89%, respectively. The R2, RMSE and RSD for the validation set were 0.978 5, 0.963 8 and 2.15%, respectively. The above results showed that NIR spectroscopy can achieve rapid, accurate and non-destructive detection of the phosphorus content in, and provide a feasible method for the refining of crude soybean oil

AUV planning and calibration method considering concealment in uncertain environments

IntroductionAutonomous underwater vehicles (AUVs) are required to thoroughly scan designated areas during underwater missions. They typically follow a zig-zag trajectory to achieve full coverage. However, effective coverage can be challenging in complex environments due to the accumulation and drift of navigation errors. Possible solutions include surfacing for satellite positioning or underwater acoustic positioning using transponders on other vehicles. Nevertheless, surfacing or active acoustics can compromise stealth during reconnaissance missions in hostile areas by revealing the vehicle’s location.MethodsWe propose calibration and planning strategies based on error models and acoustic positioning to address this challenge. Acoustic markers are deployed via surface ships to minimize navigation errors while maintaining stealth. And a new path planning method using a traceless Kalman filter and acoustic localization is proposed to achieve full-area coverage of AUVs. By analyzing the statistics of accumulated sensor errors, we optimize the positions of acoustic markers to communicate with AUVs and achieve better coverage. AUV trajectory concealment is achieved during detection by randomizing the USV navigation trajectory and irregularizing the locations of acoustic marker.ResultsThe proposed method enables the cumulative determination of the absolute position of a target with low localization error in a side-scan sonar-based search task. Simulations based on large-scale maps demonstrate the effectiveness and robustness of the proposed algorithm.DiscussionSolving the problem of accumulating underwater localization errors based on inertial navigation by error modeling and acoustic calibration is a typical way. In this paper, we have implemented a method to solve the localization error in a search scenario where stealth is considered

Muscle oxygenation trend in patients with hypertensive type 2 diabetes mellitus

本研究は,2型糖尿病患者を高血圧合併の有無により分類し,運動筋酸素動態の差異を明らかにすることを目的とした.運動は,最大随意筋力の30%の強度にて3分30秒間の足関節底屈運動を行い,終了直前30秒間に一時的動脈血流遮断法を併用して,筋酸素利用変化率(%MO2)を算出し,運動終了後の筋酸素化レベル回復時間(TR)を測定した.その結果,高血圧合併2型糖尿病患者は,ヘモグロビンA1cおよび上腕動脈-足動脈間脈波伝播速度(baPWV)が有意に高値を示し(p<0.05),%MO2 に有意差は認められなかった.またTRは有意に延長し(p<0.05),baPWVとTRには有意な正の相関関係を認めた(r=0.58,p<0.05).以上のことから,高血圧合併2型糖尿病患者では,高血圧を合併しない糖尿病患者と比較して,中等度運動での筋酸素化レベルに差異は認められないが,動脈硬化により酸素供給が低下した結果,TRが延長することが明らかとなった.Background : It is known that hypertension with type 2 diabetes mellitus increases the risk of arterial stiffness, but it is not clear whether it is accompanied by abnormal oxygenation in the exercising muscle. Methods and results: A total of 50 patients with type 2 diabetes, comprising normotensive patients (n=34, Age:53.6±8.6, BMI:23.0±3.9) and hypertensive patients (n=16, Age:53.9±8.2, BMI:24.5±3.5) , was studied. Right gastronomies muscle oxygenation was measured using near-infrared spectroscopy while resting and in a 210 sec planter flexion exercise. Muscle oxygen utilization rate (%MO2) was calculated as the increasing rate of oxygenated hemoglobin/mymoglobin during a 30 sec arterial occlusion, and reoxygenation time (TR) was calculated after arterial occlusion. The results demonstrated that glycol hemoglobin A1c (HbA1c) and baPWV in hypertensive patients (HbA1c:7.5±1.2%, baPWV:1777.9±320.7 cm/sec) were significantly different from those in normotensive patients (HbA1c:6.7±0.8%, baPWV:1520.2±211.8 cm/sec)(p<0.05, p<0.001), while no difference was observed in %MO2. Moreover, the TR was found to be slower in the hypertensive patients, and showed a positive relationship with the baPWV (r=0.58, p<0.05). From these results, it could be concluded that the arterial stiffness was caused by the decrease of oxygenation and the prolonging of TR in the hypertension with type 2 diabetes patients

Mechanical and structural investigation of porous bulk metallic glasses

The intrinsic properties of advanced alloy systems can be altered by changing their microstructural features. Here, we present a highly efficient method to produce and characterize structures with systematically-designed pores embedded inside. The fabrication stage involves a combination of photolithography and deep reactive ion etching of a Si template replicated using the concept of thermoplastic forming. Pt- and Zr-based bulk metallic glasses (BMGs) were evaluated through uniaxial tensile test, followed by scanning electron microscope (SEM) fractographic and shear band analysis. Compositional investigation of the fracture surface performed via energy dispersive X-ray spectroscopy (EDX), as well as Auger spectroscopy (AES) shows a moderate amount of interdiffusion (5 at.% maximum) of the constituent elements between the deformed and undeformed regions. Furthermore, length-scale effects on the mechanical behavior of porous BMGs were explored through molecular dynamics (MD) simulations, where shear band formation is observed for a material width of 18 nm

Synthesis of Visible-Light Driven CrxOy-TiO2 Binary Photocatalyst System Based on Hierarchical Macro-Mesoporous Silica

Hierarchical macro–mesoporous silica materials co-incorporated with Cr and Ti were directly synthesized by adopting close-packed array of polystyrene microsphere as hard template for macropore through a simple soaking-calcination way, where Si/Ti ratio was fixed at 200 and Si/Cr ratio was set between 200 and 10. Ti specie is highly dispersed in porous matrix and Cr specie mainly exists as tetra-coordinated CrO3 at higher Si/Cr ratio (Si/Cr ≥ 50), which transforms to a mixture of CrO3 and crystallized hexa-coordinated Cr2O3when Si/Cr ratio is below 50. This highly interconnected porous material co-incorporated with Cr and Ti presents highest visible-light driven photocatalytic activity at Si/Cr = 20 toward degradation of AO7. Moreover, macro–mesoporous photocatalyst presents higher activity than those of macroporous and mesoporous ones at the same Si/Cr ratio. The improved visible light driven catalytic activity is mainly attributed to effective metal to metal charge transfer from Cr(VI) to Ti(IV) benefitted from the uniform dispersion of these two species in hierarchical porous silica matrix

Synthesis, Characterization and Catalytic Polymerization of N-Methyl Imidazolium Phosphotungstic Catalyst

N-methyl imidazolium phosphotungstic salt has been synthesized and used as a special catalyst for photopolymerization of vinyl monomers. This is a fast and smooth reaction, and high molecular weight polymers with narrow polydispersity are obtained within 60 min. The compound was structurally characterized by elemental analysis, IR spectroscopy, and 1H NMR spectroscopy. The electrochemical property is determined on a CHI 660 electrochemistry workstation. The polymerization initiated by N-methyl imidazolium phosphotungstic salt showed controlling characteristics, the catalyst can be easily isolated from polymer product, and reused for at least 10 times