In order to meet the latest requirements for sensor quality test in the industry, the sample sensor needs to be placed in the medium for the cold and hot shock test. However, the existing ...environmental test chamber cannot effectively control the temperature of the sample in the medium. This paper designs a control method based on the support vector machine (SVM) classification algorithm and K-means clustering combined with neural network correction. When testing sensors in a medium, the clustering SVM classification algorithm is used to distribute the control voltage corresponding to temperature conditions. At the same time, the neural network is used to constantly correct the temperature to reduce overshoot during the temperature-holding phase. Eventually, overheating or overcooling of the basket space indirectly controls the rapid rise or decrease in the temperature of the sensor in the medium. The test results show that this method can effectively control the temperature of the sensor in the medium to reach the target temperature within 15 min and stabilize when the target temperature is between 145 °C and -40 °C. The steady-state error is less than 0.31 °C in the high-temperature area and less than 0.39 °C in the low-temperature area, which well solves the dilemma of the current cold and hot shock test.
Abstract
Boron-based catalysts exhibit high alkene selectivity in oxidative dehydrogenation of propane (ODHP) but the mechanistic understanding remains incomplete. In this work, we show that the ...hydroxylation of framework boron species via steaming not only enhances the ODHP rate on both B-MFI and B-BEA, but also impacts the kinetics of the reaction. The altered activity, propane reaction order and the activation energy could be attributed to the hydrolysis of framework B(OSi≡)
3
unit to B(OSi≡)
3−
x
(OH···O(H)Si≡)
x
(
x
= 1, 2, “···” represents hydrogen bonding). DFT calculations confirm that hydroxylated framework boron sites could stabilize radical species, e.g., hydroperoxyl radical, further facilitating the gas-phase radical mechanism. Variations in the contributions from gas-phase radical mechanisms in ODHP lead to the linear correlation between activation enthalpy and entropy on borosilicate zeolites. Insights gained in this work offer a general mechanistic framework to rationalize the kinetic behavior of the ODHP on boron-based catalysts.
The deposition of dust and condensation of fog will block the scattering and transmission of light, thus affecting the performance of optical devices. In this work, flexible polyethylene ...terephthalate (PET) foil functionalized by active dust removal and anti-fogging characteristics is realized which combines electrodynamic screen (EDS) and electro-heating devices. In lieu of traditional measurement methods of dust removal efficiency, the PSNR is employed to characterize the dust removal efficiency of the film for the first time. The results show that both dust removal and anti-fogging improve the image quality, in which the dust removal increases the PSNR from 28.1 dB to 34.2 dB and the anti-fogging function realizes a film temperature rise of 16.7 ∘C in 5 min, reaching a maximum of 41.3 ∘C. According to the high sensitivity of the PSNR, we propose a fully automatic CIS film-driven algorithm, and its feasibility has been demonstrated.
In this paper, CeO2 nanocubes with the (200)-terminated surface/graphene sheet composites have been prepared successfully by a simple hydrothermal method. It is found that the CeO2 nanocubes with ...high crystallinity and specific exposed surface are well dispersed on well-exfoliated graphene surface. The (200)-terminated surface/graphene sheet composites modified electrode showed much higher sensitivity and excellent selectivity in its catalytic performance compared to a CeO2 nanoparticle-modified electrode. The photoluminescence intensity of the CeO2 anchored on graphene is about 30 times higher than that of pristine CeO2 crystals in air. The higher oxygen vacancy concentration in CeO2 is supposed to be an important cause for the higher photoluminescence and better electrochemical catalytic performance observed in the (200)-terminated surface/graphene sheet composites. Such ingenious design of supported well-dispersed catalysts in nanostructured ceria catalysts, synthesized in one step with an exposed high-activity surface, is important for technical applications and theoretical investigations.
•A novel Shack-Hartmann wavefront sensor with adjustable spatial sampling rate.•Dynamic calibration and wavefront detection based on spherical reference wave.•3. Adjusting spatial sampling reduces ...the disadvantages of low signal-to noise ratio.•4. Ray-tracing method solves the non-conjugate wavefront reconstruction.
For the astronomical adaptive optics systems, the observation condition is constantly changing or in a regime of low photon flux. Besides, for various brightness seeing conditions, the Shack-Hartmann wavefront sensor has a matching spatial sampling that avoids extra wavefront reconstruction error. To integrate advantageous spatial samplings, we propose a novel Shack-Hartmann wavefront sensor with adjustable spatial sampling (ASS-WFS) based on spherical reference wave. In principle, only a simple movement of the microlens array (MLA) and the CCD detector in the direction of the optical axis is required to achieve variable spatial sampling. This is also obviously advantageous in the adaptive optics performance as it allows the wavefront sensor to dynamically match brightness of the observation. To demonstrate the performance of the ASS-WFS, we present the sensor in terms of the principles, the simulation, and the experiment. Results show that the ASS-WFS is able to precisely measure and reconstruct the wavefront, and also demonstrate that advantages resulting from adjusting the spatial samplings can efficiently reduce the disadvantages of low signal-to-noise ratio to boost wavefront reconstruction accuracy.
The purpose is to explore the analgesic effect of a single Nd:YAG laser dose after mandibular third molar extraction. This was a prospective randomized controlled clinical trial. Subjects were ...enrolled according to the inclusion and exclusion criteria and randomly divided into the experimental and control groups. In the experimental group, the wound was irradiated with the Nd:YAG laser (wavelength, 1064 nm; output power, 1.5 W; energy density, 45 J/cm
2
; and power density, 1.5/cm
2
, pulsed mode) immediately after mandibular third molar extraction for 120 s (30 s at each site). In the control group, the laser working tip was placed near the extraction site but not activated. The primary outcome was the visual analog scale (VAS) pain scores in both groups at 2, 4, 12, 24, 48, and 72 h and 7 days after surgery. Secondary outcomes included wound healing scores and adverse reactions. The VAS score was significantly lower in the experimental group than in the control group at 2 and 4 h after surgery, while there was no significant difference in the VAS score between the two groups at 12, 24, or 48 h or 7 days after surgery. There were no significant differences in the wound healing scores between the two groups on postoperative day 7. No adverse reactions were observed in any of the laser-irradiated areas. A single Nd:YAG laser dose was effective in reducing pain at 2 and 4 h after mandibular third molar extraction. China Clinical Trial Registry: ChiCTR2000033870 (Registration Date: 2020–6-15).
Syngas conversion into ethanol by tandem catalysis has exhibited its potential for the selective production of ethanol. For practical applications, it is desired to develop a robust catalyst system ...to enhance the CO conversion while maintaining high selectivity to ethanol. Here, we report an efficient and stable triple-tandem catalyst system consisting of CuZnAlO x /γ-Al2O3, pyridine-modified H-MOR zeolite (Py-HMOR), and Cu1Zn2AlO x , which catalyzes syngas to dimethyl ether (DME), DME carbonylation to methyl acetate (MA), and MA hydrogenation to ethanol in tandem. Both high CO conversion (52%) and satisfying selectivity to ethanol (62%, excluding CO2) were achieved simultaneously, leading to an unprecedently high ethanol space-time yield of 6.5 mmol g–1 h–1. In situ DRIFT and control catalytic tests were designed to elucidate the intrinsic reason of the high activity and stability of Py-HMOR in the tandem system. The developed tandem catalyst system presents a promising prospect for the direct ethanol manufacture from syngas.
Peroxynitrite (ONOO−) is a highly reactive species implicated in the pathology of numerous diseases and there is currently great interest in developing fluorescent probes that can selectively detect ...ONOO− in living cells. Herein, a polymeric micelle‐based and cell‐penetrating peptide‐coated fluorescent nanoprobe that incorporates ONOO− indicator dye and reference dye for the ratiometric detection and imaging of ONOO− has been developed. The nanoprobe effectively avoids the influences from enzymatic reaction and high‐concentration .OH and ClO−. The improved ONOO− selectivity of the nanoprobe is achieved by a delicate complementarity of properties between the nanomatrix and the embedded molecular probe (BzSe‐Cy). This nanoprobe also has other attractive properties, such as good water solubility, photostability, biocompatibility, and near‐infrared excitation and emission. Fluorescence imaging experiments by confocal microscopy show that this nanoprobe is capable of visualizing ONOO− produced in living cells and it exhibits very low toxicity and good membrane permeability. We anticipate that this technique will be a potential tool for the precise pathological understanding and diagnosis of ONOO−‐related human diseases.
The living daylights: A polymeric micelle‐based and cell‐penetrating peptide‐coated fluorescent nanoprobe incorporates ONOO− indicator dye (benzylselenide‐tricarbocyanine, BzSe‐Cy) and reference dye (isopropylrhodamine B, IRhB) for ratiometric detection and imaging of ONOO− in living cells. The nanoprobe exhibits good biocompatibility and membrane permeability for intracellular ONOO− imaging.
Metallic Li is considered the most promising anode material for high‐energy‐density batteries owing to its high theoretical capacity and low electrochemical potential. However, inhomogeneous lithium ...deposition and uncontrollable growth of lithium dendrites result in low lithium utilization, rapid capacity fading, and poor cycling performance. Herein, two sulfonated covalent organic frameworks (COFs) with different sulfonated group contents are synthesized as the multifunctional interlayers in lithium metal batteries. The sulfonic acid groups in the pore channels can serve as Li‐anchoring sites that effectively coordinate Li ions. These periodically arranged subunits significantly guide uniform Li‐ion flux distribution, guarantee smooth Li deposition, and reduce lithium dendrite formation. Consequently, these characteristics afford an excellent quasi‐solid‐state electrolyte with a high ionic conductivity of 1.9 × 10−3 S cm−1 at room temperature and a superior Li++ transference number of 0.91. A Li/LiFePO4 battery with the COF‐based electrolyte exhibited dendrite‐free Li deposition during the charge process, accompanied by no capacity decay after 100 cycles at 0.1 C.
Covalent organic frameworks (COFs) with abundant sulfonated groups are synthesized and further employed as the interlayer in the batteries to guide the uniform Li+ flux and realize smooth lithium deposition, where the built‐in sulfonate groups act as anchoring sites for strongly attracting Li+ and the extended planar porous structure serve as the Li+ flux channel. Therefore, Li/LiFePO4 battery with COF‐based interlayer exhibits dendrite‐free Li deposition and a no capacity decay after 100 cycles at 0.1 C.
