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In a distribution power grid with a high proportion of distributed photovoltaic (DP) connections, the real-time acquisition of the distributed photovoltaic power generation data is a costly and heavy task. In this paper, a virtual data sampling method based on Deep Belief Network (DBN) combined with a Second-order oscillating-firefly algorithm (SOO-FA) is proposed. It enables virtual data sampling from all distributed PV plants in a region where only one distributed PV plant has a complete data-sampling device and the other distributed PV plants have less expensive current sampling terminals. The firefly algorithm is utilized to continuously adjust and optimize the weights of the deep belief network, and the optimal DBN model is used to carry out the virtual collection of the power output data of the distributed PV equipment within the region. Finally, the proposed method has high accuracy for the PV output power by 100 distributed PV devices in the regional range in the simulation section.

In this paper, the energetically stable and metastable crystal structures of Mg-Li binary system are searched throughout all possible Mg concentrations by using the first-principles calculations based on density functional theory (DFT). Three stable structures are found at compositions LiMg, LiMg2 and Li2Mg3. One metastable structure is found at composition LiMg3. The formation energy, phonon spectrum, and elastic constants are calculated to evaluate the energy, dynamic and elastic stabilities, respectively. At zero temperature, both the elastic moduli (include bulk modulus B, shear modulus G, Young’s modulus E, the Poisson’s ratio ν and B/G ratio) as a function of the Mg concentration in Mg-Li binary system and the spatial direction dependences of elastic moduli are analyzed. The temperature dependents of bulk modulus and thermal expansion coefficient are also analyzed to investigate the high-temperature mechanical properties of Mg-Li binary system. With the increase of temperature, the bulk modulus of Mg-Li alloys gradually decreases and the thermal expansion coefficient gradually increases. And the calculated results also show that LiMg2 can maintain excellent mechanical strength and mechanical stability at high temperature, and has the potential of application in the high-temperature fields.

The power distribution network has many switch stations connected to distributed photovoltaics. However, the heating hazard, the partial discharge in the switchgear, and the operation conditions of those switch gears cannot be detected and identified by traditional methods in time. This paper designs a three-dimensional (3D) inspection system for those switch stations. An infrared window in the switchgear, an infrared thermal imager, and an ultrasonic partial discharge detector outside the switchgear are designed to monitor the switch station environment. Finally, with video analysis technology, the system can identify the operation condition of the switch station equipment. It is significant to monitor and manage the switch stations, thus the switch stations become safer and more reliable.

Perovskite quantum dots (QDs) with stable luminous properties are crucial to for the construction of corresponding light-emitting diodes (LEDs). Hybrid halide perovskite QDs, especially those contain iodine element emitting red light, usually demonstrate poor emission stability owing to the halide segregation. Moreover, red component is indispensable for the construction of white LEDs (WLEDs). Hence, it is essential to improve the luminous stability of hybrid halide perovskite QDs containing iodine element. Here, magnesium dopant and silica matrix were employed to improve the stability of hybrid halide CsPb(IBr)3 QDs. Red, green and blue are three primary colors for constructing WLEDs. Therefore, silica-coated CsPbBr3 QDs emitting green light were also synthesized. The fabricated silica-coated Mn:CsPb(IBr)3/PMMA film delivered good emission stability during a 42 d observation period, exhibiting the improved stability compared with the corresponding Mn:CsPb(IBr)3 QDs in solution. WLEDs were fabricated by integrating the mixture of silica-coated Mn:CsPb(IBr)3 QDs, silica-coated CsPbBr3 QDs and silicon sealant with a blue-emission LED chip. The as fabricated device exhibited a longer lifetime to be lit than that of those reported previously. During the 36 d observation period for the as fabricated device, the red emission from the silica-coated Mn:CsPb(IBr)3 QDs experienced a peak-emission shift of 34 nm, which is much less than that in Mn:CsPb(IBr)3 QDs solution. Their overall intensity downtrend combined the peak-emission shift are responsible for the spectrum shape change, so as to the fluctuation of color correlated temperature and color rendering index. Our study provides a good starting point for the further improvement of the stability of the hybrid halide perovskites QDs and the corresponding light-emitting devices. With deep studies on the synthesis method and luminous mechanism for hybrid halide CsPb(IBr)3 QDs, red-emission perovskite QDs with satisfied properties are expected to be obtained.

This paper aims to investigate the hydropower station with downstream channel (HSDC) and reveal the effect of fluctuation from downstream channel on its stability and dynamic characteristics under load disturbance. Firstly, a novel mathematical model of HSDC considering the fluctuation of downstream channel water level is established. Then, the stability and dynamic characteristics of HSDC are analysed by Hopf bifurcation. Finally, it is revealed that the effect of the fluctuation from downstream channel water level on the stability and dynamic characteristics of hydropower station. The results indicate that the HSDC is a supercritical system, and the stable domain is on the lower left to the bifurcation line in K p -K i plane. Considering the fluctuation of downstream water level, the stable domain of HSDC is wider than the reference where downstream channel water level is constant. The fluctuation of downstream water level has two-sided effect on the dynamic characteristics of HSDC, which makes the attenuation rate lager but setting time longer. Moreover, the more obviously the downstream water level changes with flow, the stronger the influence on stability and dynamic characteristics of HSDC are. Therefore, it is safer to design hydropower station and select the parameters of governor according to constant water level in engineering.

High-precision positioning in areas with unobtrusive features is difficult to achieve with visual based indoor positioning solutions. Most current solutions offer low precision and are expensive and/or require a priori training. A ceiling distributed on the same plane is regularly arranged and widespread in structured indoor environments. We propose a new monocular vision simultaneous localization and mapping (NMV SLAM) method for high-precision indoor positioning. First, image morphology technology is adopted to extract the ceiling corner accurately. Second, the geometric solution based on the a priori ceiling map realizes global positioning and makes up for the deficiency of time-consuming nonlinear optimization. Experiments show that the root mean square error of position measured by the proposed NMV SLAM process is less than 5.43 mm in a room with an entire ceiling. Moreover, the proposed NMV SLAM processes an average of 30.61 frames in 1 s on an i5-9400F central processing unit.

The bandstructure of a material, playing an important role in its electron transport property, is usually governed by the lattice configuration. Materials with a field-effect tunable band, such as bilayer [1] and rhombohedral trilayer graphene [2, 3], are more flexible for electronic applications. Here, on dual-gated twisted double bilayer graphene (TDBG) samples with small twist angle around 1∘, we observe vertical electric-field-tunable bandstructures at multiple moiré fillings with bandgap values continuously varying from zero to tens of mili-electron volts. Moreover, within the first moiré filling on both electron and hole sides, the carrier transport deviates from Fermi liquid behavior, with measured resistivity exhibiting linear temperature dependence between 1.5 K and 50 K. Furthermore, under a vertical magnetic field, the coupling between the two bilayer graphene layers can also be turned on and off by a displacement field. Our results suggest TDBG with small twist angle is a platform for studying the evolution of multiple electric field tunable moiré bands and the resulting emergent correlated electronic phases.

Focusing on the difficulty in vibration control of internal combustion power plant because of its diverse substructures and complex excitation, an abnormal vibration diagnosis and attenuation method based on the system’s whole-body vibration signals is proposed. The characteristics of the exciting forces, such as toppling torque, inertia force (or moment) and coupling centrifugal force, are analyzed. The resonance frequency distribution of the power unit is obtained by modal analysis. Then an expression that could reveal the relationship between the whole-body vibration intensity and the exciting force amplitude is established, and conclusion is drawn that different excitations would drive the system to vibrate at different frequencies. Based on this basic relation, a fault diagnosis method relying on comprehensive analysis of vibration signals in both time and frequency domain is proposed. Vibration attenuation methods targeted at specific faults are also put forward. Finally, the validity of the proposed method is verified by applying it to a 12V280 diesel generator set.

Statistical machine translation systems usually break the translation task into two or more subtasks and an important one is finding word alignments over a parallel sentence bilingual corpus. We address the problem of introducing word alignment for language pairs by developing a novel neural network model that can applied to other generative alignment models. We use Multi-layer attention model and multi-layer model with multi-head-attention mechanism on each layer provides superior translation quality. It can be trained on bilingual data without relying on word alignment. In this paper, we cast the correspondence problem directly as an optimal distance problem. We use the Gromov-Wasserstein distance to calculated how similarities between word pairs are related across languages. The resulting alignments dramatically outperform the GIZA++ and FastAlign approach, these alignments are comparable on public data sets.

Cellulose-based electroactive actuators are promising candidates for biomimetic robots and biomedical applications due to their lightweight, high mechanical strength, and natural abundance. However, cellulose-based electroactive actuators exhibit lower actuation performance than traditional conductive polymer actuators. This work reports a fast-response cellulose-based electroactive actuator based on 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) oxidized nanocellulose (TOCNF) film with layered structure fabricated by evaporation, and gold electrodes prepared by ion sputtering. The residual ions during the TEMPO oxidation process and the layered structure due to self-assembly accelerate the ion migration efficiency in actuators. The proposed actuator can reach a tip displacement of 32.1 mm at a voltage of 10 V and deflect 60° in 5 s. After applying a reverse 10 V voltage, the actuator can also be quickly deflected (42.5 mm). In addition, the actuator also shows high electrical actuation performance at low voltage (5 V). The excellent electroactive performance of as-prepared TOCNF/Au enables the feasibility to be applied to actuators.

This research uses CiteSpace software as a tool to sort out the research results of artificial intelligence-based rainfall prediction models and algorithms in the China Knowledge Network Database (CNKI) and the “Web of Science” database, summarize relevant research hotspots and topics, and identify the latest research Trends, provide a reference for further advancement of rainfall prediction models and algorithms. Through knowledge network analysis, the following conclusions are drawn: (1) The literature based on rainfall prediction models and algorithms has shown an increasing trend over time. (2) It is scientific research institutions and colleges and universities of various countries that publish a large number of relevant documents. (3) The current research trend is deep learning and meteorological satellites. Neural networks tend to study a variety of data assimilation and hybrid models. (4) Global artificial intelligence-based rainfall prediction models and algorithms research results show that more emphasis is placed on deep learning algorithms Application trends.

A special kind of pentamode metamaterial, which is composed of double-cone elements and forms simple-cubic lattice, is investigated in this paper. Based on finite-element method (FEM), the phonon band structure and the transmission spectrum of the pentamode metamaterial are calculated, and then the pentamodal behavior of this structure is theoretically verified from two aspects, i.e. the physical properties and the mathematical definition. Results show that in the phonon band structure, there is a wider single-mode band gap, corresponding to the remarkable loss in the transmission spectrum. The ratio of bulk modulus B to shear modulus G is more than 300, which is obviously larger than that of traditional materials. Except for the isotropic bulk modulus B, the other mechanical moduli are all anisotropic. Five of six eigenvalues of elastic coefficient matrix are nearly zero for the microstructure, and only one is non-zero. These results demonstrate that this metamaterial microstructure performs excellent pentamodal characteristics, and also conforms to the mathematical definition of "pentamode".

Absrtact. In this study, 5 years-old ‘Shine Muscat’ grapes were used as experimental materials to study the effects of different fruit-preserving and puffing-fruit formulations on the formation of fruit russet and fruit quality of ‘Shine Muscat’ grapes by using random block experiment and spraying water as control. The results showed that J3 treatment significantly decreased the fruit russet index, but significantly increased the fruit weight, brightness value, yellow saturation and soluble sugar content of ‘Shine Muscat’ grapes. The content of phenolic compounds in pericarp was decreased by different formulas, which indicated that the formation of fruit russet was closely related to the accumulation of phenolic compounds. The content of lignin in the pericarp was decreased by different treatments at fruit ripening stage, and the content of lignin in J3 treatment was the lowest, which indicated that it inhibited lignin production. The results of this experiment can provide guidance for the high-quality production of ‘Shine Muscat’ grape.

Four year old ‘Shine Muscat’ grape was used as the test material to spray amino acid calcium and water-soluble calcium solution on grape leaves and ears during fruit expansion and turn-color stages. A randomized block test was conducted to study the effects of exogenous calcium fertilizer on the formation of fruit russet and phenolic compounds in ‘Shine Muscat’ grape. The test was used to set the concentration of amino acid calcium solution to 1000 times, and to set the concentration of calcium water solution to 1500 times. With spraying water as a control. The results showed that: compared with water spraying, fruit russet was reduced in fruit expanding stage and turn-color stage, which could inhibit the accumulation of lignin, total phenol and total flavonoids, and affect the accumulation of eight phenolic acids in fruit peel. Spraying calcium fertilizer at fruit expanding stage was more conducive to inhibiting the accumulation of phenolic acids than that at turn stage, while spraying 1000 times of amino acid calcium at turn-color stage was more conducive to inhibiting the accumulation of gallic acid, caffeic acid, quercetin, coumaric acid and ferulic acid in pericarp than spraying 1500 times of water-soluble calcium and water. The results of this experiment can provide some guidance for grape production to supplement exogenous calcium and improve fruit quality.

Five year old “Shine Muscat” grape was used as material to spray amino acid calcium and water-soluble calcium solution on grape leaves and ears during fruit expansion and color changing stages. The effects of exogenous calcium fertilizer on the formation of fruit rust and fruit quality of “Shine Muscat” grape were studied in a randomized block design with 1000 times of amino acid calcium solution and 1500 times of water-soluble calcium solution, and the spraying water was used as the control. The results show that: compared with calcium fertilizer in fruit expanding stage, it is more beneficial to the accumulation of sugar components in pericarp to spaying calcium fertilizer in turn-color stage. The content of sugar in pulp can be increased by spraying calcium fertilizer compared with water in fruit expanding stage. Spraying calcium fertilizer in turn-color stage can promote the degradation of malic acid and citric acid in the pericarp of mature grape and inhibit the degradation of tartaric acid. Spraying calcium fertilizer in fruit expanding stage can promote the degradation of citric acid in mature grape pulp, while calcium amino acid can inhibit the degradation of oxalic acid and tartaric acid and promote the degradation of malic acid. Spraying calcium fertilizer in turn-color stage can promote the degradation of organic acids in mature grape pulp. Combined with the content of soluble sugar and titratable acid, spraying 1500 times of soluble calcium in fruit expansion period is beneficial to improve the fruit quality of “Shine Muscat” grape.

Different effective synthetic strategies of chiral intermediate (S)-3,3′-bis(azidomethyl)-2,2′-bis(methoxymethyl)-1,1′-binaphthalene are described from the original material (S)-3,3′-bis(hydroxymethyl)-2,2′-bis(methoxymethyl)-1,1′-binaphol. The 1HNMR and HRMS spectroscopic analyses have been used to confirm the synthesis of (S)-6.

A chiral fluorescent sensor containing (S)-BINOL and 1, 2, 3-triazole moieties was synthesized via through a nucleophilic substitution reaction and a click reaction with high total yield. The fluorescence responses of chiral compounds W1 and ferric ion were investigated by a fluorescence spectra. The fluorescence emission intensity of W1 at λ = 390 nm (λex = 300 nm) was quenched quickly upon the coordination with a ferric ion while other metal ions had no obvious change.

Based on the data of energy consumption and economic growth in Fujian Province from 2007 to 2018, the correlation degree between energy consumption and economic growth is studied by using grey correlation analysis. The results show that the the gross domestic product (GDP) of Fujian Province is significantly correlated with the energy consumption products. The correlation degree is greater than 0.7. The order of the correlation degree is oil, coal, hydropower, wind power nuclear power and natural gas. The correlation is significant between the total amount of energy consumption and the value added of primary, secondary and tertiary industries in Fujian Province. The correlation degree is more than 0.6, indicating that the economic growth of Fujian Province is more dependent on energy consumption. Fujian Province should optimize its energy structure, vigorously develop clean energy and realize the development strategy of low-carbon economy.

In this paper co-polarization spatial Goos–Hänchen (GH) shifts (Δss/λ and Δpp/λ) of periodic chiral metamaterials are investigated. The numerical results show that the enhancement of GH shifts is affected by the incident frequency, the incident angle, the period and the volume fraction of the dispersive chiral layer. For s polarized waves, GH shifts are always enhanced negatively with one Brewster angle, but two Brewster angles arise when the period is large and specific. For p polarized waves there are two Brewster angles in general, at which the GH shifts can be greatly enhanced with negative and positive peaks. More Brewster angles appear when the period is sufficiently large and specific. The transition of negatively and positively enhanced GH shifts is sensitive to large frequencies, and can be tuned by changing the frequency slightly. The transition can also be adjusted by varying the volume fraction of the dispersive chiral layer and the period of the structure.

Based on the two-dimensional dielectric wedge-shaped photonic crystal, we studied the existence of two kinds of equivalent refractive indexes (negative refractive index is −1, positive refractive index is 1.897) in the photonic crystal by means of fast Fourier transform (FFT), as well as its influence on the optical propagation characteristics was discussed. By adjusting the wedge angle of the photonic crystal to eliminate the influence of positive refraction beam on the imaging, the sub wavelength focusing with half-width less than half of a wavelength can be realized. The numerical results show that the Full Width Half Maximum (FWHM) of the image point can reach a minimum of 0.41 λ when the wedge angle of the photonic crystal is 73°.

We report a search for new physics signals using the low energy electron recoil events in the complete data set from PandaX-II, in light of the recent event excess reported by XENON1T. The data correspond to a total exposure of 100.7 ton⋅day with liquid xenon. With robust estimates of the dominant background spectra, we perform sensitive searches on solar axions and neutrinos with enhanced magnetic moment. It is found that the axion-electron coupling g Ae < 4.6 × 10–12 for an axion mass less than 0.1 keV/c 2 and the neutrino magnetic moment μν < 4.9 × 10–11 μ B at 90 % confidence level. The observed excess from XENON1T is within our experimental constraints.

We report on further development and application of a general purpose readout system, the Scalable Readout System (SRS). The SRS was introduced by the RD51 collaboration in 2009 in a common effort. Several front-end Application Specific Integrated Circuits (ASICs) were implemented in the system, of which the APV25 is most commonly used. Recently, we implemented the VMM ASIC, developed to read out detectors of the ATLAS New Small Wheel. We developed hardware components as well as FPGA firmware and computer software. With this latest implementation called SRS VMM, other groups intend to perform experiments and detector R&D. In our application targeted at the NMX macromolecular diffractometer, one of the instruments foreseen at the European Spallation Source (ESS), SRS VMM was used to read out prototype detectors. Small scale versions were successfully tested at neutron sources and a full scale version was constructed. In those test beams, the feasibility of the detector and readout electronics design could be demonstrated.

The tensile tests of a metal spring and a rubber band are studied comparatively. It is found that the elastic force of rubber band is proportional to its elongation in a certain range of deformation, which satisfies Hooke’s theorem. This is same as the result of the metal spring. By comparing the vibration property of the systems composed of metal spring and rubber band respectively, it is found that the property of “intrinsic” damped vibration of the rubber band oscillator is completely different from that of the viscous damped vibration of the harmonic oscillator. It is concluded that the static mechanical property of rubber band is similar to that of metal spring, but its dynamic mechanical property is completely different from that of metal spring.

Since the liquid discharge problem has been incorporated into the line of sight, many scholars have done a lot of research on it. In this paper, experiments on the pre-breakdown period in underwater plasma discharge were carried out. Among the parameters of underwater plasma discharge, the electrode structure is firstly taken account by virtue of its intuitive, easy-to-process, and diversity. With the refinement of the application of liquid discharge in liquid-electric processing, research on the effect of electrode structure on underwater plasma discharge is deepening. In this paper, two sets of electrode groups were proposed in a pioneering manner through the theoretical analysis and precise control of the experimental parameters. Based on the experimental results, rigorous and reliable analysis and summary were demonstrated. The conclusions of this paper would be helpful for water environmental treatment.

The AC/DC hybrid distribution network is large in scale and high in voltage level, and contains more sources and loads, and the degree of control is more complicated. Therefore, the disconnection of the line in the AC/DC hybrid distribution network, the AC/DC fault of the system, and the change of the operating state of the flexible DC device may cause the operating mode of the system to change. In this paper, the corresponding system operation mode is proposed for the typical hand-hand AC/DC hybrid distribution network. The operating mode of the flexible DC device, the switching conditions of the flexible DC device, and the switching strategy are studied. The influence of the hot standby operation on the distribution network is analyzed, and the seamless switching of the flexible DC device is realized.

Computer network optimization refers to the design of network protocol according to the solution mechanism and implementation scheme given by optimization theory, so as to solve the problems of task scheduling, resource allocation, system parameter allocation and network resource deployment in the network. With the rapid expansion of the coverage of computer networks and the advent of the network era, the development of artificial intelligence has been promoted. Artificial intelligence has been widely used in computer network technology. In order to further improve the service quality of the network, not only the existing network protocols need to be evaluated, but also the network reconstruction project needs to be carried out. Based on the current situation of computer network service optimization, this paper analyzes the difficulties in the process of optimization and puts forward the corresponding countermeasures, and expounds the importance and necessity of the integration of artificial intelligence technology for the optimization of computer network service quality.

With the development of network technology, network is more and more closely related to people’s lives. Network security has been paid more and more attention, and the research on network security has gradually been put on the agenda. The main purpose of computer network security research is to extract the system data and factors related to computer network security and establish a model to analyze computer network security. Computer security concerns people’s vital interests. Now, hacker attacks and virus intrusions often occur, which threaten people’s privacy and security. The research work of security analysis needs to extract the system resources and security factors related to computer network security and establish a security model oriented to security analysis. Based on the analysis of the connotation and current situation of computer network security, this paper points out the main problems existing in the network security model, in order to explore a practical model for improving computer network security analysis.

The famous ancient supernova SN 1054 could have been too bright to be explained in the "standard" radioactive-powered supernova scenario. As an alternative attempt, we demonstrate that the spin-down of the newly born Crab pulsar could provide a sufficient energy supply to make SN 1054 visible at daytime for 23 days and at night for 653 days, where a one-zone semi-analytical model is employed. Our results indicate that SN 1054 could be a "normal" cousin of magnetar-powered superluminous supernovae. Therefore, SN 1054-like supernovae could be a probe to uncover the properties of newly born neutron stars, which provide initial conditions for studies on neutron star evolutions.

The effects of different buckle shed time on catalase (CAT) activity and malondialdehyde (MDA) content in grape leaves (tender, function and old leaves) were studied involving the following: without buckle shed (CK), buckle shed on January 1st, 2018 (BS I), buckle shed on January 20th, 2018 (BS II), sampled 6 times with interval one week. The result showed that buckle shed increased the CAT activity of grape tender and function leaves, the grape tender leaves of BS I and BS II at the sampling date 4 had the highest and increased by 32.36% and 39.14% respectively, but the grape function leaves of BS I and BS II at the sampling date 2 had the highest and increased by 25.46% and 26.53% respectively. The buckle shed had no significant effect on CAT activity of grape old leaves in early sampled date. The different buckle shed time had no significant effect on CAT activity of grape leaves. Buckle shed increased the MDA content in grape tender leaves, the grape tender leaves of BS I and BS II at the sampling date 4 had the highest and increased by 204.0% and 202.7% respectively. Buckle shed decreased the MDA content in grape function leaves, the grape function leaves of BS I and BS II at the sampling date 2 had the lowest and increased by 46.39% and 48.19% respectively. The MDA content of grape old leaves in the early sampled was decreased compared with control, but in the later sampled increased.

The effects of buckled shed of different time on the superoxide dismutase (SOD) and peroxidase (POD) activities of grape leaves (tender, function and old leaves) were studied by without buckle shed (CK), buckled shed on January 1st, 2018 (I) and buckled shed on January 20th, 2018 (II), sampled 6 times with interval one week. The results showed that the SOD and POD activities of grape tender leaves and functional leaves under buckled shed on January 1st and buckled shed on January 20th treatments were increased to varying degrees. However, the activities of SOD and POD of grape old leaves under buckled shed on January 1st and buckled shed on January 20th treatments increased in the early stage and decreased in the later stage. The SOD activities of old leaves sampled for the sixth time were higher 17.17% and 12.00% than those of the two treatments, respectively. The POD activity in old leaves in the sixth sampling of treatment buckled shed on January 1st decreased 11.00%. The results showed that the activities of SOD and POD in tender leaves, functional leaves and early old leaves of grapes were increased by the treatment of buckled shed, which indicated that the treatment of buckled shed could promote the growth of grapes and enhance resistance, and there was no significant difference between the buckled shed on January 1st and buckled shed on January 20th treatments.

Bichromatic circularly polarized fields provide a useful tool to probe the ionization dynamics. In this work, we compare the photoelectron momentum distribution in few-cycle bichromatic field of different helicities. The spectral features are analyzed with semiclassical trajectories derived from the strong field approximation. In particular, the interference fringes in momentum distribution are investigated by tracking the ionization time and tunneling exits of released photoelectrons. Different types of trajectories that contribute to the interference fringes are elucidated.

Global air pollution causes a lot of health problems every year, especially in developing countries. In this study, chemical decomposition and spray technology are used to deal with the six main pollutants in the air. Acid and alkaline sprays are used to treat different pollutants, which cause the chemical pollution gas to be toxic and left behind in the reaction device. The air purifier with traditional filter technology has better effect.

The purpose of this paper is to investigate the effects of lactic acid bacteria (LAB) fermentation on the volatile aroma components and sensory qualities of hawthorn pulp (HP). High performance liquid chromatography (HPLC) and electrons Nasal combined with HS-SPME-GC-MS were used to analyze the effects of lactic acid bacteria fermentation on the organic acid content and volatile compounds of hawthorn pulp (HP). The results showed that the content and type of organic acids and volatile compounds in HP were significantly improved after fermentation of lactic acid bacteria, and the sensory score was also significantly increased.

Fluorescence lifetime measurement in the time domain requires excitation from a well separated single bunch using synchrotron light sources. In the colliding mode of the Beijing Electron Positron Collider II (BEPCII), a hybrid filling pattern was realized such that a single bunch was placed in the middle of a large gap between two multi-bunch groups. Detection of fluorescence lifetime, based on the excitation of the light pulse from this designated single-bunch, was established at Beamline 4B8 of the Beijing Synchrotron Radiation Facility (BSRF). The timing signal of the BEPCII was utilized as a trigger to gate this fluorescence event. L-Tryptophan amino acid, a known lifetime standard, was selected to assess the lifetime measurement performance. The measured lifetime was consistent in both colliding and single-bunch mode with the time resolution down to 450 ps. Moreover, both the bunch purity and the fine structure of the hybrid filling pattern were characterized.

Dy films, deposited on the surface of sintered Nd–Fe–B magnets by magnetron sputtering, were employed for grain boundary diffusion source. High coercivity sintered Nd–Fe–B magnets were successfully prepared. Effects of sputtering power and grain boundary diffusion processes (GBDP) on the microstructure and magnetic properties were investigated in detail. The dense and uniform Dy films were beneficial to prepare high coercivity magnets by GBDP. The maximum coercivity value of 1189 kA m−1 could be shown, which was an amplification of 22.3%, compared with that of as-prepared Nd–Fe–B magnet. Furthermore, the improved remanence and maximum energy product were also achieved through tuning grain boundary diffusion processes. Our results demonstrated that the formation of (Nd, Dy)2Fe14B shell surrounding Nd2Fe14B grains and fine, uniform and continuous intergranular RE-rich phases jointly contribute to the improved coercivity.

We introduce the general catalysts for pure entanglement transformations under local operations and classical communications in such a way that we disregard the profit and loss of entanglement of the catalysts per se. As such, the possibilities of pure entanglement transformations are greatly expanded. Remarkably, we find an interesting phenomenon that, in some situations, incomparable pairs ${| ��> ,| ��> \} $ and ${| ��> ,| ��^{\prime}> \} $ can assist each other mutually so as to realize the transformation $| ��> | ��> \to| ��> | ��^{\prime}>$. We also design an efficient algorithm to detect whether a $k\times k$ general catalyst exists for a given entanglement transformation. This algorithm can as well be exploited to witness the existence of standard catalysts., 5 pages, 2 figures. An example added, small revisions

To carry out the precise measurement of large-scale complex workpieces, accurately calibration of the stereo photogrammetric system has becoming more and more important. This paper proposed a flexible and reliable camera calibration of stereo photogrammetric system based on quaternion with one-dimensional optical reference bar, which has three small collinear infrared LED marks and the lengths between these marks have been precisely calibration. By moving the optical reference bar at a number of locations/orientations over the measurement volume, we calibrate the stereo photogrammetric systems with the geometric constraint of the optical reference bar. The extrinsic parameters calibration process consists of linear parameters estimation based on quaternion and nonlinear refinement based on the maximum likelihood criterion. Firstly, we linear estimate the extrinsic parameters of the stereo photogrameetric systems based on quaternion. Then with the quaternion results as the initial values, we refine the extrinsic parameters through maximum likelihood criterion with the Levenberg-Marquardt Algorithm. In the calibration process, we can automatically control the light intensity and optimize the exposure time to get uniform intensity profile of the image points at different distance and obtain higher S/N ratio. The experiment result proves that the calibration method proposed is flexible, valid and obtains good results in the application.

In this paper, we present an elementary theory on the existence and robustness of horseshoes under perturbations in terms of stability of crossing. The framework is developed in the setting of 2D Euclidean space but can be generalized to metric spaces. As an application, we give a rigorous verification of the existence of a horseshoe in the Ikeda map.