Search

Edible vegetable oils could provide energy, essential fatty acids and various micronutrients required in the body. However, vegetable oils, being rich in unsaturated fatty acids, are susceptible to oxidation to produce a series of oxidation products that are harmful to health after consumption, due to environmental factors during processing and storage. Therefore, this paper introduced the causes of oxidation in edible vegetable oils, the mechanism of lipid autoxidation, the main oxidation pathways and the hazards of oil oxidation, and the research progress of antioxidation on edible vegetable oils were also reviewed, including low-temperature storage, gas-conditioned storage and adding single or combined antioxidants. Meanwhile, the current problems on the lipid oxidation and the antioxidant measures in edible vegetable oils were discussed. This work could be expected to provide some references for the researches focusing on the oxidative stability of edible vegetable oils.

The rapid simulation of the dynamic performance of electromechanical devices such as solenoid valves and relays is important for product development and design. A magnetic circuit model of the non-saturated direct-acting electromechanical motion device is improved, and then coupled with the motion equation of the mechanism to realize the rapid simulation of the electromechanical motion device. In contrast to the ideal magnetic resistance in the conventional magnetic circuit model, the non-saturated total magnetic resistance is expressed by a cubic polynomial of the movement displacement of mechanism. The four undetermined coefficients of the polynomial are calibrated by the simulation values of static magnetic force and inductance at the upper and lower motion limits. The improved magnetic circuit model can more accurately predict the changes of magnetic attraction force and inductance with the motion displacement. Furthermore, coupled with the motion equation of the electromechanical motion device, the improved model establishes an improved magnetic circuit-motion coupled model and realizes fast second-level simulation of an electromagnetic brake and valve in the Simulink system, which can greatly reduce the finite element simulation time while maintaining simulation accuracy.

The effects of three cooking methods: microwave (25 W/g for 3.5 min), baking (60 ℃ for 2 h), and water boiling (100 ℃ for 15 min) on the major nutrients and bioactive substances in two varieties of purple-fleshed potato were analyzed so as to provide a scientific basis for the thermal processing of purple-fleshed potato. The results showed that after heat treatment, the contents of vitamin C, ash, starch, and total phenols (calculated as chlorogenic acid) decreased. After microwave treatment, the protein contents of the two varieties increased by 3.29% and 3.21%, but decreased by 2.20% and 1.97% after baking and 1.91% and 1.41% after boiling treatment, respectively. The anthocyanin content of the Black Diamond cultivar increased by 22.92% and 16.67%, respectively, after microwave and water boiling treatment, but decreased after baking treatment. In addition, microwave treatment significantly improved the reducing capacity of purple-fleshed potato anthocyanin extract, and the anthocyanin extract significantly enhanced the expression levels of nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase 1 (HO-1) in RIN-m5F pancreatic islet β cells and reduced the expression level of nuclear transcription factor kappa B (NF-κB). In conclusion, microwave treatment was the best heat treatment method for purple-fleshed potato.

The team of oil chemistry and processing technology from Academy of National Food and Strategic Reserves Administration (Academy of NFSRA) has made great contributions to the research and establishment of the quality evaluation standard for main oilseeds and oils in China. A series of standards have been developed or revised based on: (1) investigation and quality analysis of main oilseeds varieties in China, (2) tracking and referencing the development trend of international standards and advanced foreign standards, (3) database of oilseeds qualities and processing formed through undertaking the national and industrial research projects, (4) establishment of the inspection techniques and evaluation methods for vegetable oil qualities. Accordingly, the quality standard systems for oilseeds and oils have been improved, and the processing technology levels have been promoted. The sound and rapid development of industries happened because the market has run in a more and more standardized way. All the standards of oilseeds and oils have served the economic construction generally, and are also providing technical support for safeguarding national interests and the safety of the oil industry.

On the occasion of the 30th anniversary of the journal “Science and Technology of Cereals, Oils and Foods”, this paper summarized the development and prospects in the field of oil chemistry and processing technology in Academy of National Food and Strategic Reserves Administration (Academy of NFSRA) over the past 30 years. This scientific research carried out by the Academy of NFSRA in the field of oil chemistry and processing technology over the past 30 years and its outstanding contributions to promoting the development of the industry were also reviewed. According to the development strategy under the new situation of China, the highlighted work in the field of oil chemistry and processing technology was summarized, and the new opportunities and challenges faced by the field of oil chemistry and processing technology research was further prospected.

Objective: This study aimed to investigate the microbial succession and the changes of volatile flavor substances in traditional fermented fish. Methods: Traditional microbial counting methods, high-throughput sequencing, gas chromatography-mass spectrometry（GC-MS） were applied to explore the effects of different fermentation times of traditional fermented fish （0~180 d） on microflora changes and the volatile flavor compounds during the processing of the solid fermentation process of traditional fermented fish as well as on the correlation between them. Results: The results showed that the main dominant bacterial genera included Staphylococcus, Lactobacillus, etc. That there were 69 volatile flavor components in fermentation process, mainly including acids, alcohols, aldehydes, ketones, N compound；benzene compound, alkyl aromatic compound, esters. and their types and contents changed with the fermentation time. The correlation analysis results showed that Staphylococcus was positively correlated with N-containing compounds and negatively correlated with alcohols. Lactobacillus was significant positively correlated with nonanoic acid,1-octen-3-ol, nonanal, tetradecanal, 2, 4-dimethyl styrene, decyl ene, ethyl caproate （0.01＜P＜0.05）. And negatively correlated with heptenic acid, 3-methylbutyric acid, 2, 3-butanediol, 2, 6-di-tert-butyl p-cresol, Copaene and myristic ethyl ester. Although the relative abundance of microorganisms such as Citrobacter, Turbulella, Psychrobacter, Acinetobacter, Oceanospirillales and Flavobacteria was relatively low in the whole fermentation process, there was also an obvious correlation with the formation of flavor substances. Conclusion: The microbial community and volatile flavor compounds have a series of changes with fermentation time, and there is a significant correlation between them.

More and more attention has been paid to the safety and nutrition of edible vegetable oil. Maintaining the nutritional quality and stability of edible vegetable oil has become a key issue in the oil industry. Rosemary extract, as a natural antioxidant, has good oxidation resistance, which could inhibit the oxidative deterioration of oil and prolong the storage time for keeping the good sensory and nutritional quality of oil. Also, it shows better stability in high temperature environments. The oil is taken mainly through hot processing in China, so the natural nontoxic, efficient and heat-resistant antioxidant is desired for Chinese edible oils. In this paper, the application research progress of rosemary extract in edible vegetable oil was reviewed, providing theoretical reference for the antioxidant research of rosemary extract in oil.

[Purpose/Significance] Based on the investigation of scientific data literacy ability of domestic graduate students, this paper constructs the scientific data literacy ability training system of university libraries, so as to provide targeted suggestions for university libraries to carry out scientific data literacy education. [Method/Process] Based on the data literacy evaluation research, a questionnaire was designed, and graduate students s of Jiangnan University were taken as the sample. [Results/Conclusions] The research shows that the data consciousness and data ethics of postgraduates in domestic universities are showing an optimistic trend. But students' ability of data collection, data organization and management, data utilization and preservation need to be improved, especially the data analysis capabilities need to be urgently strengthened. Based on this, this paper constructs a training system in accordance with the current situation of scientific data literacy of university graduates from four aspects of training objectives, contents, methods and evaluation.

An analysis method for the volatile components of squeezed Camellia oleifera seed oil was established by using automatic sample preparation-headspace solid phase microextraction (HS-SPME)combined with gas chromatography-mass spectrometry (GC/MS) technology.The optimum extraction conditions are:Divinylbenzene/Carboxen/Polydimethylsiloxane (DVB/CAR/PDMS) solid-phase microextraction column,extraction temperature 60 ℃,extraction time 50 min,resolution time 5 min,compared with traditional manual water bath extraction method,it has higher total peak area and main peak area; A total of 47 volatile components in pressed camellia seed oil were identified and quantified using this method,of which aldehydes are the main volatile components in camellia seed oil; The characteristic flavor compounds of pressed camellia seed oil obtained by relative odor activity value (ROAV) analysis are 2-hydro-3-hydroxy-4,4-dimethyl-2(3H)furanone,dihydroxy-2(3H)furanone,2-methyl Propionaldehyde,phenylacetaldehyde,nonanal,n-hexanal,trans-2-nonenal,decanal,1-heptanol,3-ethyl-3,5-dimethyl-pyrazine.

Nine chlorogenic acid isomers were extracted from Yunnan Catimor green coffee beans by water-alcohol extraction method. Single factor experiments were carried out to study the material number,ratio of liquid to material, water extraction temperature, extraction time, alcohol concentration and alcohol extraction temperature, and response surface design was used to optimize the water alcohol extraction process. The results showed that the extraction rate of water-alcohol extraction method (5.21%) was significantly higher than that of water extraction method (4.29%)；The alcohol concentration and the ratio of liquid to material had significant influence on the extraction rate of chlorogenic acids (P ≤ 0.01). The optimum extraction conditions of chlorogenic acids isomers by water-alcohol method optimized by single factor and response surface were: alcohol extraction temperature of 60 ℃, extraction time of 11.67 min,material mesh of 60, liquid to material ratio of 16.07, alcohol concentration of 20.16%, the extraction rate of chlorogenic acid isomers were of 5.31%.

To improve the utilization level of rice bran, it is very important to study the accurate separation of key components in rice bran. In this paper, the influence of grinding wheel type, grinding speed and grinding time on the contents of key components in rice bran, such as wax, crude fat and crude protein, was studied, and was characterized and modeled by scanning electron microscopy (SEM), multiple regression analysis and correlation analysis. The results showed that the key components in brown rice were distributed alternately from the outside to the inside, which were wax ester layer, fiber layer, fat-protein layer and starch layer. The highest content of the key components in rice bran and its milling technology combination were of wax 0.67% (860 rpm, 1.0 min), crude fat 18.37% (1 060 rpm, 1.0 min), crude protein 18.59% (960 rpm, 2.0 min), crude fiber 16.85% (760 rpm, 0.5 min) and starch 41.12% (1 060 rpm, 2.5 min), respectively; Grinding wheel type had a very significant impact on wax content and crude fiber content (P

One of the most important research fields in Synthetic Aperture Radar (SAR) technology is to improve the accuracies of the number, location, classification, and other parameters of targets of interest. SAR information processing can be mainly divided into two tasks: imaging and interpretation. At present, research efforts on these two tasks are relatively independent. Many algorithms have been developed for SAR imaging and interpretation, and they have become increasingly complex. However, SAR interpretation has not been made simpler by improvements in the imaging resolution. The low recognition rate of key targets, in particular, has yet to be adequately resolved. In this paper, we use a “data driven + intelligence learning” method to improve the information processing ability of airborne SAR based on SAR imaging & interpretation integration. First, we analyze the feasibility and main problems of SAR imaging & interpretation integration using a “data driven + intelligence learning” method. Based on the results, we propose a SAR learning-imaging method based on “data driven + intelligence learning” with the goal of producing an imaging network. The proposed learning-imaging framework, parameter selection method, network training method, and preliminary simulation results are presented, and the key technical problems to be solved are identified and analyzed.

More than 140 camellia oleifera seeds and oil samples were collected from the main producing areas of camellia oleifera by investigating the resources of camellia oleifera in China.The quality of camellia oleifera seeds and the fatty acid composition and quality index of camellia oleifera seed oil were studied and analyzed.The national standard GB/T 11765—2018 “camellia oleifera seed oil” was revised by collecting and analyzing the data.The main technical contents of the standard is introduced in detail in order to help readers understand the intention of revising the various indicators easily.

BACKGROUND Beijing is a typical geographical distribution area of selenium deficiency. However, some research results in recent years indicate that the soils in some areas reaches the level of selenium enrichment. It is important to study the characteristics of selenium distribution in these areas for the research of a selenium-rich environment in Beijing and the development of selenium-rich land resources. OBJECTIVES To discuss the characteristics of selenium content in soil and crops, the source of selenium and the relationship between selenium in soil and other elements such as carbon, iron and phosphorus, and to evaluate the safety of selenium-rich land. METHODS Samples of 1297 topsoil, 25 sets of corn and corresponding root soil and 15 rock samples were collected from an eco-conserving division of the Daqinghe River watershed. The content of selenium in these samples was determined by atomic fluorescence spectrometry. Methods of correlation analysis and multivariate statistical analysis and GIS technology were used to study the characteristics of selenium content in soil and crops, the source of selenium enrichment, and the relationship between soil selenium and other elements such as carbon, nitrogen, phosphorus and sulfur, and the safety of selenium-rich land was evaluated. RESULTS The results showed that the soil selenium content ranged from 0.055 to 0.465mg/kg and that the background value was 0.257mg/kg, which show selenium-rich characteristics. 360.4km2 selenium-rich land resources was identified. The selenium content of corn ranged from 0.028 to 0.70mg/kg, and the geometric mean was 0.20mg/kg. 80% of the corn samples were selenium-rich products. The selenium-rich soil and the selenium-rich crops had the same spatial distribution, which indicated that the soil was an important source of selenium in crops. CONCLUSIONS Geological background and soil parent material are the key control factors affecting the distribution of selenium-rich land resources. Dark rock series of fluvial deposition are a crucial source of selenium in soil. The overall environmental quality of selenium-rich land is clean and safe, and only 0.2% of the area (3.23km2) contains soil heavy metal (Cd, Hg, Pb) content, which exceeds the level of risk management control. Due to these findings, attention needs to be paid during selenium-rich land development.

Soybean isoflavone is a sort of secondary metabolite formed during the growth of soybean. It is mainly distributed in the cotyledons and hypocotyls of soybean in the form of glycosides and free aglycones. It has been shown that free soybean isoflavonehas a great many beneficial physiological functions, such as antioxidation, anticancer and cancer suppression, cardiovascular protection, prevention of osteoporosis and female climacteric syndrome. With the advancement of science and technology, soybean isoflavones have been widely applied in various foods. The reported extraction methods of isoflavones from soybean and their advantages and disadvantages were reviewed, and the biotransformation of glycosidic soybean isoflavones to free aglycones was also discussed. It is believed that this will be helpful for the application research of soybean isoflavones.

In the presence of yaw angular velocity, a body will deviate from its ideal flight path, which will affect imaging of Downward-Looking Sparse Linear Array 3D Synthetic Aperture Radar (DLSLA 3D SAR). In this paper, an imaging model including yaw rate is established. Furthermore, Doppler frequency modulation, which is related to cross-track coordinates and not azimuth coordinates, was theoretically calculated. Thus, a cross-track signal could be reconstructed to obtain the cross-track coordinates before azimuth signal compression. Based on the parametric sparse representation, the velocity and yaw rate of the platform were estimated, and the azimuth signal was compressed. Moreover, a deformation correction method is proposed to correct image deformation. The simulation results demonstrate the validity of the proposed method.

The technique of radar feature extraction, imaging, and recognition of target with micro-motions has become one of the most potential research directions in the field of radar target accurate recognition. In this paper, the concept of micro-motion is first introduced briefly. Subsequently, the achievements of echo modeling, feature extraction, imaging, and identification of micro-motion targets are summarized. Several typical frontier applications are then introduced. Finally, the future development trends of the research are discussed.

The micro-motion feature is one of the important characteristic information of spatial target recognition. However, the existing multifunctional Multi-Input Multi-Output (MIMO) radar usually has to allocate a large number of continuous time resources for target micro-motion feature extraction after target searching and tracking, which leads to a low real-time performance of target recognition and poor overall performance of radar system. To solve this problem, this paper presents a multi-target micro-motion feature extraction method for MIMO radar based on tracking pulses. First, according to the azimuth information of each target, the MIMO radar transmitting waveform is designed, and the tracking pulses are transmitted simultaneously for targets with different directions. On this basis, by considering the micro-motion feature extraction performance and the target tracking performance synthetically, the transmission time series of the tracking pulses are optimized. Finally, the narrowband tracking pulses are directly used to simultaneously extract the micro-motion features of the targets in different directions, which makes it no longer necessary to allocate additional radar resources for target feature extraction. Consequently, the real-time recognition performance and the working efficiency of radar are improved significantly. Simulations demonstrate that when the signal-to-noise ratio is larger than –10 dB, the micro-motion features of multi-targets can be extracted accurately, which verifies the effectiveness and robustness of the proposed method.

In this paper, a Sinusoidal Frequency Modulation Fourier-Bessel Transform (SFMFBT) is proposed for micro-Doppler (m-D) target feature extraction. Initially, the definition of SFMFBT is given, and then, some of its properties are analyzed. A method to reduce frequency extraction error is then introduced based on error analysis. Finally, some issues in the frequency extraction of discrete signals are discussed. After comparing with the values of Fourier-Bessel Transform (FBT), SFMFBT introduces the parameter k-resolution into the kernel function of FBT so that accuracy of the signal decomposition is distinctly improved. In addition, from the error analysis in SFMFBT, Bessel-based signal decomposition methods can be used for feature extraction, whose application scope is extended. Simulation results verify the effectiveness of the proposed method for a group m-D target and also verifies its robustness when SNR>0 dB.

Solid-solid phase change materials (SSPCMs) have gained significant attention for their energy storage properties, which are exothermic at low temperatures and heat-absorbing at high temperatures. However, the encapsulation of PEG has resulted in reduced energy storage density, thermal conductivity and flexibility due to the presence of a non-thermally active backbone. Therefore, current research is primarily focused on enhancing thermal conductivity and energy storage density while ensuring flexibility. The article reviews three approaches to improve-thermal conductivity and energy storage density while ensuring flexibility. This article also reviews four approaches to improve energy storage density and flexibility of PEGs: doped porous materials, microencapsulation, electrostatic spinning technology and cross-linking of polymers. Future research directions and challenges are also discussed in this reviews. [ABSTRACT FROM AUTHOR]

The coastal saltmarshes in China have been seriously degraded and artificial restoration strategies have become one of the primary measures to protect the coastal habitats. In this study, we investigated efficient restoration techniques for native saltmarsh plants in vacant habitats within the project area of the Ecological Control of Spartina alterniflora and Improvement of Birds Habitats in the Shanghai Chongming Dongtan Bird National Nature Reserve in the Yangtze Estuary. Through field and pilot experiments, we analyzed the effects of propagule types and transplanting methods on the restoration efficiency of Scirpus mariqueter, a dominant saltmarsh species in the Yangtze Estuary. We further evaluated the cost and efficiency of various restoration strategies. Our results indicated that: 1) The corm seedlings of S. mariqueter had higher flood tolerance, and were suitable for use in the habitats with higher environmental heterogeneity. 2) Across the four treatments for S. mariqueter restoration, the most economically efficient treatment was to transplant low-density corm seedlings without sediment, with an investment cost of approximately ¥ 10100 per hectare. The costs were ¥41100, ¥30000, and ¥ 120100 per hectare for high-density without sediment, low-density with sediment, and high-density with sediment restoration, respectively. 3) After nearly 5-yr efforts, the S. mariqueter community of Plot C3 in project area had achieved a coverage of over 60%, marking a relatively successful large-scale field restoration. This study could provide the foundation and support for large-scale coastal saltmarsh restoration projects. [ABSTRACT FROM AUTHOR]

A multiple targets cognitive radar tracking method based on Compressed Sensing (CS) is proposed. In this method, the theory of CS is introduced to the case of cognitive radar tracking process in multiple targets scenario. The echo signal is sparsely expressed. The designs of sparse matrix and measurement matrix are accomplished by expressing the echo signal sparsely, and subsequently, the restruction of measurement signal under the down-sampling condition is realized. On the receiving end, after considering that the problems that traditional particle filter suffers from degeneracy, and require a large number of particles, the particle swarm optimization particle filter is used to track the targets. On the transmitting end, the Posterior Cramér-Rao Bounds (PCRB) of the tracking accuracy is deduced, and the radar waveform parameters are further cognitively designed using PCRB. Simulation results show that the proposed method can not only reduce the data quantity, but also provide a better tracking performance compared with traditional method.

A novel compressed sensing imaging algorithm for high-squint Synthetic Aperture Radar (SAR) based on a Nonlinear Chirp-Scaling (NCS) operator is proposed. First, the echo signal of high-squint SAR is analyzed, and a novel imaging method based on the Nyquist-sampled echo signal is proposed. With the proposed method, the range migration is corrected and the coupling problem in the range and azimuth directions is solved. Then, to solve the problem of high-squint SAR imaging using undersampled echo signals, the NCS operator and compressed sensing algorithm based on this operator are constructed. Imaging results are obtained by solving an optimization problem. The proposed method can recover a sparse scene using undersampled echo data. Furthermore, it can recover a nonsparse scene using fully sampled data. Finally, simulations show the effectiveness of the proposed method.

One of the unique characteristics of a ground target is its micro-motion, which can be used for target classification and identification. In this study, methods for vibrating ground target detection and feature extraction of the one-stationary bistatic frequency-modulated continuous-wave Synthetic Aperture Radar (SAR) are studied. The Displaced Phase Center Antenna (DPCA) technique is adopted to suppress the ground clutter, allowing the ground-vibrating targets to be detected. Analysis of the received signal indicates that the DPCA processing results in a slow time-varying envelope, known as the Slow Time Envelope (STE). The STE has a direct effect on the micro-Doppler time-frequency curve, which therefore cannot be obtained unbroken. Furthermore, vibrating features are extracted by utilizing their relationship with the STE term. Finally, some simulations are provided to validate the theoretical derivation and effectiveness of the proposed extraction method.

This paper presents the design of a handheld pseudo random coded Ultra-WideBand (UWB) radar for human sensing. The main tasks of the radar are to track the moving human object and extract the human respiratory frequency. In order to achieve perfect penetrability and good range resolution, m sequence with a carrier of 800 MHz is chosen as the transmitting signal. The modulated m-sequence can be generated directly by the high-speed DAC and FPGA to reduce the size of the radar system, and the mean power of the transmitting signal is 5 dBm. The receiver has two receiving channels based on hybrid sampling, the first receiving channel is to sample the reference signal and the second receiving channel is to obtain the radar echo. The real-time pulse compression is computed in parallel with a group of on-chip DSP48E slices in FPGA to improve the scanning rate of the radar system. Additionally, the algorithms of moving target tracking and life detection are implemented using Intel’s micro-processor, and the detection results are sent to the micro displayer fixed on the helmet. The experimental results show that the moving target located at less than 16 m far away from the wall can be tracked, and the respiratory frequency of the static human at less than 14 m far away from the wall can be extracted.

Video Synthetic Aperture Radar (ViSAR) system offers high imaging frame rate, and high resolution, and it is consequently used to investigate and locate near-moving targets. Compared with microwave SAR, the practical application of ViSAR is restricted by motion compensation caused by short wavelength. Even slight platform vibrations cause significant variations in the phase of echo signal.Thus, it is imperative to analyze the motion compensation and the error of ViSAR. In this study, the results show that imaging is affected less in the direction of flight direction and by low vibration in the direction of the slant range. In contrast, high-frequency vibration in the direction of the slant range requires higher compensation accuracy. Given the particularity of ViSAR's motion compensation, a compensation scheme is designed to achieve high compensation precision .The effectiveness of the scheme is verified by ViSAR imaging simulation experiments.

Deceptive jamming can get vivid jamming effect on Multiple-Input Multiple-Output (MIMO) radar with very low power. In order to remove those deceptive targets, one method based on signal jittering, data fusion and fake target notch filtering is proposed in this paper. Multiple orthogonal binary phase codes are used as transmitted signals, before each time of transmission each transmitter will choose one signal from all the orthogonal codes, images of echoes of all kinds of codes are detected with constant false alarm rate. Targets detected in images of echoes of all different signals are fused to determine to be real or not, fake targets will be nulled by notch filtering in the image, therefore, weak real targets can be detected in the next round of detection, in this way fusion and notch filtering are implemented again and again until no fake targets exist. The effect of deceptive jamming on radar will be removed completely. Simulation result testifies that the method based on signal jittering, data fusion and notch filtering can help MIMO radar remove deceptive jamming completely.

Compared to the monostatic radar, bistatic radar has many special characteristics because of its spatial complexity. Bistatic Inverse Synthetic Aperture Radar (Bi-ISAR) can be employed as a radar imaging tool for obtaining non-cooperative target images. In this study, we first analyze the range and azimuth resolution of a Bi-ISAR system. To analyze this azimuth resolution and its spatial-variety characteristic, a definition called con-Doppler bandwidth is introduced, which helps overcome the difficulty of the target’s viewing angle diversity calculation. Then, a detailed investigation is conducted to study the micro-Doppler effect caused by the vibration and the rotation of the target in the Bi-ISAR system. By comparing the difference in the micro-Doppler effect between the Bi-ISAR system and the Mono-ISAR system, we modify the extended Hough transform to extract the real micro-motion features of the targets. Finally, we provide some simulation results to validate the theoretical derivation and to illustrate the effectiveness of the proposed method.

In order to extract the micro-motion signatures in condition of Migration Through Range Cells (MTRC) of micro-motional scatterers and azimuthal undersampling in wideband radar, a method based on the Orthogonal Matching Pursuit (OMP) decomposition of the complex image is proposed. By making use of the amplitude and phase information of “range-slow-time image”, a set of micro-Doppler signal atoms is constructed in the complex image space. The OMP algorithm in vector space is then extend to the complex image space to obtain the micro-motion parameters. Simulations demonstrate the proposed method can extract the micro-motion signatures when MTRC of micro-motional scatterers is occurred, and can also work well when the sampling rate is lower than the Nyquist sampling rate.

To solve the problem of difficult focus, serious geometry distortion and large cross sidelobe in high-squint mode synthetic aperture radar (SAR) ground moving target imaging (GMTIm), a high-squint SAR GMTIm algorithm based on the ωk algorithm with spectrum rotation is proposed. Firstly, a moving target echo signal model with accurate slant-range is deduced in detail to obtain preliminary imaging result and extract the region of interest (ROD moving target data. Then, the phase compensation function is constructed and the minimum entropy algorithm is utilized to finish moving target parameter estimation. According to the estimated parameter, the phase of ROI data is compensated to get the focused moving target image. Furthermore, spectrum rotation eliminates geometry distortion, and the sparsity enhancement method decreases the moving target sidelobe. By doing so, focused, no geometry distortion and low sidelobe moving target image is obtained. Simulation results validate the effectiveness of the proposed algorithm. [ABSTRACT FROM AUTHOR]

To study the effect of different curing temperatures on the hydration reaction of slag cement, four different curing temperatures of 20,40,60 and 90 t were set in this study. The initial hardening of cement was detected by ultrasonic detector, the hydration heat of samples was analyzed and tested by isothermal calorimeter, and the hydration reaction mechanism of slag cement at different temperatures has been systematically analyzed combined with micro test analysis. The results show that the hardening time of slag cement will decrease with the increase of temperature. With the increase of curing temperature, the hydration heat release of slag cement is also greater, and the hydration degree is also greater. However, compared with high temperature, the slow rate of hydration heat release of slag cement at low temperature is more obvious, and the peak value of heat release is also delayed. The change of curing temperature does not change the type of hydration products, but only affects the total amount of Ca(OH)2 and calcium vanadium stone. The higher the temperature, the less the total amount of Ca(OH)2 and the more the total amount of vanadate. When the curing temperature is 40 t, the slag has been completely covered by hydration products, and the gel on the slag surface becomes needle like. [ABSTRACT FROM AUTHOR]

In order to study effects of different fertilization methods on postharvest hardness of kiwifruit,'Donghong' kiwifruit was picked at physiological maturity stage and was stored at room temperature. Hardness, softening rate, content of starch, protopectin, soluble pectin, cellulose, enzyme activities of polygalacturonase ( PG), pectin methylesterase (PME), cellulase (Cx), and β-galactosidase (β-Gal) were frequently sampled and analyzed. Results showed that reasonable fertilization could inhibit the hardness loss and the decrease of nutritious components (starch, protopectin and cellulose), and delay the increase of soluble pectin and repress the enzyme activities such as PG, PME, Cx, β-Gal and amylase. Hardness of kiwifruit cultivated by different fertilization methods was negatively correlated with soluble pectin content and activities of PG, Cx, β-Gal and amylase (P<0.01), and positively correlated with protopectin, cellulose and starch content (P<0.01). Combination of compound chemical fertilizer, organic fertilizer and biological fungus fertilizer in kiwifruit production can significantly delay fruit softening and prolong fruit storage. [ABSTRACT FROM AUTHOR]

Flavonoids are a kind of polyphenolic compounds with 2-phenyl flavone structure, which are widely found in fruits, vegetables and tea leaves, and have the functions of anti-oxidation, reducing blood lipids, regulating blood glucose and inhibiting inflammation. Numerous studies have corroborated that the metabolic absorption and physiological function of flavonoids in vivo are closely related to gut microbiota. In this paper, we elucidated the interaction between flavonoids and gut microbiota from the structure and function of gut microbiota, types and products of microorganisms involved in metabolism, types and activities of metabolic enzymes and other aspects, summarized the mechanism of flavonoids in preventing obesity, diabetes, irritable bowel syndrome, cardiovascular disease and Alzheimer's disease by regulating gut microbiota, so as to provide theoretical basis for the application of flavonoids in functional foods. [ABSTRACT FROM AUTHOR]

A novel terpolymer (JAV) was prepared by free radical polymerization with acrylamide, vinyl neodecanoate and methylacryloxymethyl trimethoxysilane as monomers, and the properties of JAV for lithium-ion battery were characterized and analyzed. The results show that JAV has good thermal stability and the residual mass fraction remains above 85% at 360 . Compared with traditional polyvinylidene fluoride adhesives, the electrodes prepared by JAV have excellent mechanical properties, and can effectively maintain the electrode integrity in the battery cycle when used in silicon-based lithium-ion battery. Moreover, JAV has high bonding strength, the electrode can be stored in electrolyte for more than 15 days, and the assembled battery has a high initial specific capacity of 3 976. 23 mA-h/g with an initial Coulomb efficiency of 96. 24%. After 20 cycles of charge and discharge at current density of 0. 1 C, the battery still has a capacity of 517.86 mA'h/g, and a stable solid electrolyte interface film is formed, which can effectively improve the problem of rapid capacity decay of silicon-based lithium-ion battery. [ABSTRACT FROM AUTHOR]

In order to improve the corrosion resistance of the silicone coatings, the graphene-modified hyperbranched polysiloxane (HBPSi-PDM-SGO) coatings have been prepared by silane-modified graphene oxide (SGO) doping with hyperbranched polysiloxane. The effect of different mass fractions of SGO on the thermal stability and corrosion resistance of the HBPSi-PDM-SGO coatings has been discussed. The results show that HBPSi-PDM-SGO has excellent thermal stability and good anti-corrosion performance. In addition, the silane-modified graphene oxide also improves the mechanical properties and shortens the curing time. [ABSTRACT FROM AUTHOR]

Using 3-isocyanatopropyl dimethoxysilane, polypropylene glycol (PPG), N-(βaminoethyl)-γ-aminopropyltrimethoxysilane as the main raw materials, silane-terminated polyether resins with different R values (molar ratio of isocyanate groups to hydroxyl groups) were prepared by polyaddition reaction. The structure of the product was characterized by infrared spectroscopy and hydrogen nuclear magnetic resonance spectroscopy, and the properties of the cured products were tested. The results show that with the increase of R value, the tensile strength of the cured silane-terminated polyether resin increases from 0.29 MPa to 0.63 MPa, the Shore A hardness increases from 12 to 33, and the elongation at break increases from 476.3 % to 127.2% ; the temperature drops when the mass loss rate is 10% and 30%, and the temperature rises when the mass loss rate is 50%, 80%, and at the end of thermal decomposition. The water absorption rate after immersing in deionized water for 7 days is changed from 15. 8% to 9.2% ; the silane-terminated polyether resin has good mechanical properties, thermal stability and water resistance, and can be used in the field of sealants. [ABSTRACT FROM AUTHOR]

In order to design the assembly process plan based on the 3D model, the digital modeling method for 3D assembly process planning model was studied. Firstly, the process of assembly process planning was divided into two stages, such as the stage for rough assembly process planning and the stage for complete assembly process planning. According the different stages of the assembly process planning, three kinds of assembly process planning model were proposed, namely the disassembly process planning model, rough assembly process planning model and complete assembly process planning model. The representation method for the above three kinds of model and the auxiliary assembly process information was given, the mapping mechanism for them was proposed. Finally, based on the above modeling method, an assembly process planning system based on 3D model was developed, and 3D assembly process plan for an engine model was designed using the system. [ABSTRACT FROM AUTHOR]

A large amount of nitrogen (N) fertilizers poured into the fields severely pollute the environment. Reasonable application of N fertilizer has always been the research hotpot. The effects of N management on maize N utilization and residual nitrate N in soil under maize/ soybean and maize/ sweet potato relay strip intercropping systems were reported in a field experiment in southwest China. It was found that maize N accumulation, N harvest index, N absorption efficiency, N contribution proportion after the anthesis stage in maize/ soybean relay strip intercropping were increased by 6. 1%, 5. 4%, 4. 3%, and 15. 1% than under maize/ sweet potato with an increase of 22. 6% for maize yield after sustainable growing of maize/ soybean intercropping system. Nitrate N accumulation in the 0-60 cm soil layer was 12. 9% higher under maize/ soybean intercropping than under maize/ sweet potato intercropping. However, nitrate N concentration in the 60-120 cm soil layer when intercropped with soybean decreased by 10. 3% than when intercropped with sweet potato, indicating a decrease of N leaching loss. Increasing of N application rate enhanced N accumulation of maize and decreased N use efficiency and significantly increased nitrate concentration in the soil profile except in the 60-100 cm soil layer, where no significant difference was observed with nitrogen application rate at 0 to 270 kg∙hm-2. Further application of N fertilizer significantly enhanced nitrate leaching loss. Postponing N application increased nitrate accumulation in the 60-100 cm soil layer. The results suggested that N application rates and ratio of base to top dressing had different influences on maize N concentration and nitrate N between maize/ soybean and maize/ sweet potato intercropping. Maize N concentration in the late growing stage, N harvest index and N use efficiency under maize/ soybean intercropping increased (with N application rate at 180-270 kg∙hm-2 and ratio of base to top dressing = 3:2:5) and decreased nitrate leaching loss with yield reaching 7757 kg∙hm-2 on average. However, for maize/ sweet potato, N concentration and use efficiency and maize yield increased significantly with N application rate at 180 kg∙hm-2 and ratio of base to top dressing=5:5 than that under other treatments with yield reaching 6572 kg∙hm-2. Under these circumstances, it would be possible to realize maize high yield, high efficiency and safety of N management under maize/ soybean and maize/ sweet potato relay strip intercropping systems. [ABSTRACT FROM AUTHOR]

The internal flow of a lubricant vane pump in aircraft engine is simulated using the computational fluid dynamics software Star-cd to estimate the influences of inlet and outlet pressures on its internal flow. A self-compiled code is called by the subroutines of Star-cd to generate the moving mesh of vane pump, especially to capture the gap shape between vane and stator. Rayleigh cavitation model and Menders SST k-ω) model are used in the simulation. The calculated flow rates are obtained under different inlet and outlet pressures. The simulation results demonstrate that the transient flow rate at the inlet is stable, while the transient flow rate at the outlet fluctuates significantly. The calculated results also demonstrate that the flow rate increases significantly with the increase in inlet pressure. And with the increase in outlet pressure, the back flow is increased and the collapse velocity of cavitation is also increased, resulting in a small reduction in the flow flux. [ABSTRACT FROM AUTHOR]

To solve the problem of signal separation in the system of integration of radar and communication, a signal model based on random stepped-frequency Orthogonal Frequency Division Multiplexing ( OFDM) radar pulses is proposed. By the frequency agility, the communication data is modulated on the radar pulses and then transmitted through random stepped- frequency pulses. Thus, the target range image can be acquired from the correlation of the echo signal and the reference signal, while the communication data is demodulated by means of frequency detection through bandpass filter group without signal separation. Finally, simulation results show that the designed signal realizes decimeter range resolution imaging and high-rate data transmitting in Mbit per second, which can satisfy the requirements of transmitting the mass data. [ABSTRACT FROM AUTHOR]