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The random distribution model (RDM) and uniform distribution model (UDM) were used to simulate the thermal sterilization of canned fruit. The RDM was established with the radiation function, and the stability of RDM results was analyzed by simulating temperature change during thermal sterilization and determining the sterilization parameter F value of the slowest heating zone (SHZ). The performance of the distribution models in simulating thermal sterilization heating process of canned fruit with different shapes was studied using the UDM and RDM of canned yellow peach (hemispherical shell), pear (sphere), and coconut (cube). Simulation results were compared with experimental results. The flow field and temperature field distributions were used in analyzing the influence of fruits shape on the accuracy of the models. The simulation results of different RDMs were consistent with the temperature change and F value, indicating that the RDMs had stable simulation results. When the contact between two types of fruit was a point, the UDM can be used in the numerical simulation of thermal sterilization. When the contact was a non-point, the RDM was more accurate in simulating thermal sterilization. This study provides constructive suggestions for the simulation of thermal sterilization of canned fruit with different shapes.

The binary polyhydrides of heavy rare earth lutetium that shares a similar valence electron configuration to lanthanum have been experimentally discovered to be superconductive. The lutetium polyhydrides were successfully synthesized at high pressure and high temperature conditions using a diamond anvil cell in combinations with the in-situ high pressure laser heating technique. The resistance measurements as a function of temperature were performed at the same pressure of synthesis in order to study the transitions of superconductivity (SC). The superconducting transition with a maximum onset temperature (Tc) 71 K was observed at pressure of 218 GPa in the experiments. The Tc decreased to 65 K when pressure was at 181 GPa. From the evolution of SC at applied magnetic fields, the upper critical field at zero temperature {\mu}0Hc2(0) was obtained to be ~36 Tesla. The in-situ high pressure X-ray diffraction experiments imply that the high Tc SC should arise from the Lu4H23 phase with Pm-3n symmetry that forms a new type of hydrogen cage framework different from those reported for previous light rare earth polyhydride superconductors.

Halide perovskite (HP)-based optoelectronics, particularly lasers, have attracted considerable attention thanks to their outstanding low threshold and tunable bandgaps.

Wurtzite CuInS2 exhibits great potential for optoelectronic applications because of its excellent optical properties and good stability.

Asia minor bluegrass (Polypogon fugax) is a common and problematic weed throughout China. P. fugax that is often controlled by acetyl-CoA carboxylase (ACCase) inhibitors in canola fields. Herein, we confirmed a P. fugax population (R) showing resistance to all ACCase inhibitors tested with resistance indexes ranging from 5.4–18.4. We further investigated the resistance mechanisms of this R population. Molecular analyses revealed that an amino acid mutation (Asp-2078-Gly) was present in the R population by comparing ACCase gene sequences of the sensitive population (S). In addition, differences in susceptibility between the R and S population were unlikely to be related to herbicide metabolism. Furthermore, a new derived cleaved amplified polymorphic sequence (dCAPS) method was developed for detecting the Asp-2078-Gly mutation in P. fugax efficiently. We found that 93.75% of plants in the R population carried the Asp-2078-Gly mutation, and all the herbicide-resistant phenotype of this R population is inseparable from this mutation. This is the first report of cross resistance to ACCase inhibitors conferred by the Asp-2078-Gly target-site mutation in P. fugax. The research suggested the urgent need to improve the diversity of weed management practices to prevent the widespread evolution of herbicide resistance in P. fugax in China.

The storage time of cold box is an important subject. At present, the research method of the storage time is mainly experiment, and the theoretical research is incomplete. Therefore, in this work, a theoretical modeling combined with a network method of radiation heat transfer, shape factor of heat conduction, and sensible heat of refrigerant was proposed to calculate the storage time of a cold box at various ambient temperatures and amounts of refrigerant. The experimental and simulation results were used to verify the theoretical modeling of the storage time. The influences of sensible heat of refrigerant and radiation heat transfer in the cold box were analyzed. The stability of the theoretical modeling was studied via simulation of the different cold box and refrigerant materials. The results of the accuracy of theoretical model confirmed that the maximum error between the theoretical and the experimental storage times is 8.45%, and error between the theoretical and the simulation results is 7.51%, indicating that the sensible heat of refrigerant and radiation heat transfer have big impacts on the storage time. The stability of theoretical model is confirmed under different box and refrigerant materials. The storage time model has stability on different box materials and refrigerant materials. The theoretical model can be severed as a fundamentally guidance for the cold box production design.

The influence of three different states on the thermoacoustic instability characteristics of Rijke tube was compared in order to reseach the influencing factors of thermoacoustic oscillation by using the Rijke tube model with stack as the heat source. The thermoacoustic oscillations are numerically simulated from the start-up to the saturation state, and the effects of the temperature on the dynamic viscosity and the thermal conductivity are compared. The results show gravity has a greater influence than the thermoacoustic oscillation caused by thermal buoyancy, and it is related to the inner balance of the tube after the gravity and the temperature gradient caused by the protrusion and the temperature gradient caused by the reduction of the amplitude dissipation. For the comprehensive comparison of the two variable parameters, it is found that when the viscosity coefficient changes with temperature and the thermal conductivity is a fixed value, both of them decrease by 49.5% with the temperature change rate. This result far exceeds the viscosity coefficient itself influences.

Optical coherence tomography (OCT) is a high-resolution imaging technology probing the internal structure of multilayered tissues. Since it provides subsurface fingerprint information that is identical to the surface texture but unaffected by any surface defects, OCT-based fingerprints open up a new domain for establishing robust and high-security automatic fingerprint identification systems (AFISs). However, the development of OCT-based fingerprint recognition is hindered by the lack of public OCT-based fingerprint database for algorithm analysis and testing. This article, for the first time, established an OCT-based fingerprint database with thousands of fingers using our custom-built acquisition device. The website of this data set is https://github.com/CV-SZU/ . Moreover, the images included in the database were selected after quality evaluation based on image resolution, image size, effective measured area, and the number of extractable features. Finally, case studies, including antispoofing, multiple subsurface fingerprint reconstruction, and fingerprint verification, were discussed based on the developed database. The database can serve as a benchmark for developing effective antispoofing, live detection, and high-accurate fingerprint recognition algorithms. It will significantly promote the research in the area of fingerprint biometric and will also advance the development of commercial products.

This paper presents an integrated control strategy for a starter/generator (S/G) system based on five-phase dual-stator winding induction machine (FPDWIM). The FPDWIM has a cage-type rotor and two sets of stator windings. One is a five-phase control winding (CW), and the other is a five-phase power winding (PW). In the starting mode, the FPDWIM works as a motor. The CW provides both active power and reactive power to drive the engine. In the generating mode, the CW mainly handles reactive power while the PW outputs active power. To achieve the integration of the starting and generating controls, indirect CW-flux-oriented control (ICWFOC) to operate in both starting and generating modes is proposed in this paper. In starting mode, the CW current and flux are controlled to output a constant starting torque; while in the generating mode, both CW and PW dc bus voltages are regulated. In this way, the principles and structures of the control strategies in both modes are compatible, resulting in a simpler implementation and improved performance. With the proposed control strategy, the system can complete the starting–generating operation with a smoother transition process. Simulation and experimental results are compared to validate the proposed control strategy.

The starter/generator (SG) system is widely used in various applications, including more-electric/hybridelectric aircraft (MEA/HEA) and hybrid electric vehicles (HEVs). The electric machine operates as a motor to provide the required torque to start the engine. Once the engine starts, the same electric machine transforms to a generator to produce electrical power. With the advantages of a simple and robust structure, low cost and maintenance, and a good overload capability, the cage-type induction machine (IM) is a competitive candidate for SG systems.

A control-winding direct power control (CWDPC) strategy for a dc generating system based on the five-phase dual-stator winding induction generator is proposed and investigated in this article. For this generator, the flux-oriented control is usually employed in the previous work mainly for the sake of good static performance. However, the present control strategy has the limitation of the further enhancement of the dynamic properties. This article explores a CWDPC strategy to upgrade the dynamic performance of this generating system. The fundamental active power of the five-phase control winding (CW) relates to its dc bus voltage while the dc bus voltage on the five-phase power-winding (PW) side is related to the control of five-phase CW fundamental reactive power. By replacing inner current loops to power control loops, the CW instantaneous fundamental active and reactive powers are calculated through the power observer and regulated directly through two power-control loops. In the transient process, the CW fundamental active power changes slightly while the reactive power can be quickly controlled for fast recovery of the dc bus voltage on the five-phase PW side. As the system has an additional control degree of freedom, the third harmonic is also considered in the proposed strategy, and the corresponding implementation is given as well. The simulation and experimental results demonstrate that using the proposed CWDPC strategy, the system has shorter transient time and lower voltage change in the dynamic response than the flux-oriented control strategy, which means the dynamic performance is further improved.

Searching for superconductivity in single element with high Tc is of great interest both for fundamental science & potential applications due to the easy recipe. It is especially interesting to explore high Tc superconductivity in transition metal elements wherein the conventional BCS theories suggest that d electrons are not favorable to form high Tc superconducting state. Here we report discovery of surprisingly robust superconductivity up to 310 GPa with almost constant Tc above 20K in a wide pressure range from 108GPa to 240 GPa in titanium. The maximum Tconset above 26 K and zero-resistance Tczero of 21 K are record-high values hitherto achieved among elemental superconductors. This finding is in sharp contrast to the theoretical predications based on the pristine electron-phonon coupling scenario. Measured normal state conductivity reveals significant s-d scattering. Quantum calculations show strong s-d transfer and d-band dominance, indicating correlation driven contributions to the robust high-Tc superconductivity seen in dense titanium. Different from most high-Tc superconductors that are either complex ceramic or intermetallic compounds, titanium metal is much easier to process and hosts notably higher and more robust Tc and critical magnetic field Hc compared to the widely used superconducting NbTi alloy. This study opens a fresh promising avenue for rational design and discovery of high-Tc superconductors among simple materials via pressure tuned unconventional mechanism.

It is challenging to search for high T

The amorphous selenium (a-Se) was studied via x-ray diffraction (XRD) under pressures ranging from ambient pressure up to 30 GPa at room temperature to study its high-pressure behavior. Two compressional experiments on a-Se samples, with and without heat treatment, respectively, were conducted. Contrary to the previous reports that a-Se crystallized abruptly at around 12 GPa, in this work we report an early partially crystallized state at 4.9 GPa before completing the crystallization at around 9.5 GPa based on in-situ high pressure XRD measurements on the a-Se with 70 °C heat treatment. In comparison, crystallization pressure on another a-Se sample without thermal treatment history was observed to be 12.7 GPa, consistent with the previously reported crystallization pressure. Thus, it is proposed in this work that prior heat treatment of a-Se can result in an earlier crystallization under high pressure, which helps to understand the possible mechanism caused by the previous controversial reports on pressure induced crystallization behavior in a-Se.

Halobenzoquinones are frequently detected as disinfection by-products in drinking water. Among identified halobenzoquinones, 2,6-dichloro-1,4-benzoquinone (2,6-DCBQ) is particularly toxic and is frequently detected in drinking water. Synthetic aromatic antioxidants discharged to source water may increase the risk of 2,6-DCBQ formation, as many studies suggest that aromatic compounds are the most likely precursors to 2,6-DCBQ. Herein, we investigated the formation of 2,6-DCBQ from chlorination of three model aromatic antioxidants, including 3-tert-butyl-4-hydroxyanisole (BHA), 2,6-di-tert-butyl-4-methylphenol (BHT) and bis(4-tert-butylphenyl)amine (BBPA). Only BBPA produced 2,6-DCBQ under chlorination, while chlorination of BHA and BHT formed α, β-unsaturated C