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To extract and transport the residual heat from mine return air over long distances, and considering the high moisture content and large volume of return air, along with the heat transfer theory of heat pipe systems, this paper designs a gravity-type split heat pipe air supply system for mine return air heat recovery. This system can transfer the recovered low-temperature residual heat to the mine's fresh air platform for preheating, meeting the anti-freezing heat demand at the mine shaft entrance and successfully realizing the extraction of low-temperature heat sources for industrial application. Through continuous three-day testing of certain heat exchange modules, the results show that the system can raise the temperature of low-temperature fresh air by 12℃ to 16.5℃, achieving the goal of preventing freezing at the shaft entrance. These findings demonstrate practical industrial application value.

Lactic acid bacteria (LAB) plays an important role in the production of sourdough, and has a significant impact on its flavor and other qualities. In order to select LAB starter culture for specialty sourdough and develop differentiated sour dough bread, this study evaluated the glucose metabolism capacity, organic acid production capacity and flavor characteristics of LAB strains isolated from different kinds of traditional fermented foods, and their effects on the flavor of sourdough and bread were also verified. The results showed that there were 6 LAB strains with strong glucose metabolism and acid production performance, and excellent flavor characteristics. The volatile flavor substances produced by these strains were mainly composed of alcohols, esters, ketones, aldehydes, acids, and other compounds. Among them, two Lactobacillus plantarum strains might be the main contributors of special flavors such as sourness, fruitiness and rice wine flavor to sourdough bread. These obtained strains provide resources for the development of sourdough starter culture with characteristic aroma components, and have potential for industrial application.

In order to study the quality change of coffee malt premixed powder with the extension of storage period, the coffee malt premixed powder was stored at the environment where the temperature is 25 ℃ and 35 ℃, respectively, and the relative humidity is 50% respectively. Its moisture, fatty acid value and falling value were monitored during the whole storage period. The volatile compounds were separated and identified by solid phase microextraction accompanying gas chromatography-mass spectrometry during the whole storage period. The results demonstrated that with the extension of storage period, the overall moisture content shows a falling trend, while the fatty acid value and falling value show an overall rising trend. The higher the storage temperature, the more significant the change is 41 kinds of main volatile compounds of coffee malt ready mixed powder were identified. It mainly includes 13 kinds of aldehydes, 15 kinds of heterocycles, 7 kinds of esters, 4 kinds of alcohols and 2 kinds of ketones. Among them, the relative concentration of aldehydes (n-hexanal, nonanal, trans-2-nonenal) showed an increasing trend with the extension of storage period.

The backflow and back-pressure propagation induced in a pulse detonation combustor (PDC) are the main factor in causing the thrust losses of a pulse detonation engine. In order to suppression the backflow propagation of a PDC, the aero-dynamic suppression strategy was implemented in this work. A total of ten isolators composed of different geometries were designed. A single-pulse detonation experiment was conducted by using the stoichiometric ethylene/enriched-oxygen mixture. It is shown that when the back-pressure has propagated about 0.86 the length of PDC, the propagation speeds and the pecks of the back-pressure in the isolator, which composed of the Venturi tube (V) and a long tube with 1.5 times diameter of the PDC, can be reduced by 10% and 20%, respectively, comparing with the base isolator. Comparing with the isolators that without the Tesla valve (T), the propagation speed of the back-pressure in the cases with the Tesla valve can be additionally reduced above 27.3%. Comparing with the isolators that without the slit (S), the peaks of the back-pressure in the cases with the slit can be decreased about 25%. The average decay rate of the back-pressure peaks can be highly increased if the cone (C) is introduced. It is found that the CVST-type isolator is the optimal. Comparing with the base isolator, the backpressure propagated in the CVST-type isolator can decrease about 50% and 40.5% of propagation speed and pressure peaks, respectively, and can increase the average decay rate of the back-pressure peaks by a factor of two.

Objective: To broaden the selection of strains for fermenting fresh rice noodle and develop the application of different strains in fresh rice noodle （FRN）. Methods: With gelatinization, texture, cooking stretching, electronic nose, electronic tongue and sensory evaluation as evaluation indexes, and L. fermentum FR-21, A. orientalis AO-21, L. plantarum YI-Y2013 and blank samples as influencing factors, the eating quality of FRN fermented by different strains was analyzed. Results: L. fermentum FR-21 fermentation improved the gelatinization indexes of indica rice flour, such as valley viscosity, disintegration value, final viscosity and retrogradation value, and reduced the texture viscosity of FRN, and improved its sensory hardness and typical fermented flavor （smell 4.0 points）. The FRN fermented by A. orientalis AO-21 had the lowest cooking loss （1.63%）, high texture hardness and chewability, relatively strong aftertaste, and obvious acidic odor （smell 3.7 points）. L. plantarum YI-Y2013 was similar to L. fermentum FR-21 in gelatinization index and textural viscosity, such as valley viscosity, disintegration value, final viscosity and retrogradation value （P＜0.05）, while the FRN fermented by L. plantarum YI-Y2013 had the highest extensibility （48.83±1.00）, and the smell was fragrant and pure （smell 4.6 points）. Conclusion: The controlled fermentation of three different strains can make FRN present different taste qualities, and rice noodles with different flavor qualities can be produced by using their fermentation characteristics.

Using NaAlO2 + NaOH as the electrolyte system, under constant pressure mode, the volume fraction of SiC was 45%, and the particle size was 5 μm, the surface of SiCp/Al based composite material was subjected to micro-arc oxidation treatment, and the effect of duty cycle on the microstructure and properties of the micro-arc oxidation film of SiCp/Al based composite material was studied. SEM was used to analyze the morphology of micro-arc oxidation film under different duty cycles. The phase composition of the film was studied by X-ray diffractometry. The roughness, micro-hardness and bonding force of the film were analyzed by roughness meter, Vickers hardness tester and scratch meter. The corrosion resistance of the film was studied by electrochemical workstation. Results showed that with the increase of duty cycle, the micro-arc oxidation film became continuous, the thickness showed an increasing trend, the roughness gradually increased, and the porosity gradually decreased. The duty cycle had a certain effect on the phase composition of micro-arc oxidation film. The adhesion between the micro-arc oxidation film and the substrate of SiCp/Al based composite materials first increased and then decreased with the increase of the duty cycle. The micro-arc oxidation film prepared under different duty cycles all improved the corrosion resistance of SiCp/Al based composite materials. The corrosion resistance of SiCp/Al based composite materials was the best when the duty cycle was 70%.

Butadiene-acrylonitrile-butylacrylate terpolymer (BNBR) was synthesized by emulsion polymerization method. The effects of amount of initiator, emulsifier and regulator of relative molecular weight on the emulsion polymerization rate were investigated. And the microstructure and dynamic mechanical properties were characterized. The results showed that the polymerization rate increased and the reaction induction period shortened with increasing polymerization temperature. The increasing amount of initiator and emulsifier could increase the reaction rate, while the change in the amount of relative molecular weight regulator had little effect on the reaction rate. The apparent activation energy of the BNBR was 27.97 kJ/mol, and the particle size distribution of BNBR latex was uniform. The glass transition temperature of BNBR was lower than that of nitrile rubber（NBR）with a difference of about 10 ℃. BNBR had better dynamic mechanical pro-perties at low temperature than NBR.

Yeast plays an important role in fermented cereal products, especially fermented flour products, affecting the texture, aroma, appearance and nutrition of the products. In order to select grain microbial starter and improve the quality of fermented flour products, yeasts were isolated from traditional old flour and natural flour collected from different provinces and cities in China. Yeast identification was carried out by combining morphology and 26S rDNA sequence alignment. High-sugar-resistant, heat-resistant and high-quality yeasts were screened out to verify their application characteristics in steamed bread, toast bread and frozen dough. The results showed that 65 strains of yeasts were isolated, all of which were Saccharomyces cerevisiae, and 9 strains with strong fermentation ability were screened out, among which 5 strains could improve the specific volume, texture and taste of steamed bread, and the other 4 strains were resistant to high sugar and heat, which could improve the texture and flavor of toast bread. Besides, one strain had strong frost resistance, which could prolong the vitality period of frozen dough. The discovered strain is expected to be developed into a high-quality starter for fermented grain products, improve the performance of different kinds of fermented flour products, provide differentiated products for consumers, and promote the innovative development of grain processing industry.

Objective To investigate the expression of erythropoietin-producing hepatocyte B2 (EphB2) receptor at different phases of functional recovery after middle cerebral artery occlusion(MCAO) in rats. Methods Sixty-four rats were divided into four groups:sham group and 2, 14 and 28 days after MCAO. The neurological and motor function was evaluated with a modified mNSS score at 2 d, 14 d or 28 d after surgery. The mRNA and protein in the hippocampus and cortex were measured by q-PCR and Western blot, respectively. Results Rats showed the highest mNSS score at 2 d after MCAO as compared with sham group (P＜0.001) and the score decreased with time.The protein level of EphB2 receptor in the hippocampus increased significantly at 2 d after MCAO (P＜0.05)compared with sham group, and then gradually decreased at 14 and 28 d after MCAO. The expression of EphB2 receptor showed correlation with mNSS scores. However, the expression of EphB2 receptors in the cortex and the EphB2 mRNA level in the hippocampus did not change significantly after MCAO. Conclusions The expression of EphB2 receptor in the hippocampus is up-regulated at early phase of MCAO and then decreased, which is closely correlated with functional score in rats.

Current food safety penalty list positioning fuzzy, content reiterated a lot of the current legislation, to avoid the defects of food safety substance problems. The reason is that the administrative law enforcement excessive list penalty for food safety risk, thus adopted a negative avoidance attitude. It is not only conducive to optimize the business environment, but also will cause adverse effects on food safety in a long-term view. In essence, the formulation of the exemption list is still administrative activities rather than legislative activities. The reconstruction of the food safety exemption list system should replace the current legislation in terms of detailed provisions. The exemption list should be used as the direct basis for administrative law enforcement, and a negative list is established to prevent the risk of the exemption list. By implementing the principle of active, inclusive and prudent regulation, we will balance the relationship between optimizing the business environment and maintaining food safety, so as to give full play to the role of the list of penalty exemptions.

Using deep learning models and attention mechanisms to classify fine-grained emotions of Chinese microblogs has become a research hotspot.However,the existing attention mechanisms consider the impact of words on words,and lack effective integration of the various dimensional characteristics of the words themselves (such as word meaning,part of speech,semantics and other characteristic information).In order to solve this problem,the paper proposes a dual weight mechanism WDWM (word and dimension weight mechanism),and combines it with the GCN model based on the analytical dependency tree,so that it can not only select the words that contain key information in each microblog,but also extract the important dimensional characteristics of the word and effectively integrate multiple dimensional characteristics of words,so as to capture more rich feature information.The F measure of fine-grained sentiment classification of Chinese microblogs combining dual weight mechanism and graph convolutional neural network(WDWM-GCN) reaches 84.02%,which is 1.7% higher than the latest algorithm proposed by WWW in 2020,which further proves that WDWM-GCN can effectively integrate the multi-dimensional characteristics of words and capture rich feature information.In the experiment on the classification of Sogou news data set,after the BERT model is addedto the WDWM mechanism,the classification effect is further improved,which fully provs that the WDWM has a significant improvement on the text classification model.

Based on the crack propagation theory, the multiaxial fatigue life algorithm of rubber was developed using Python language and verified by experiments. The fatigue lives of silicone rubber dumbbell uniaxial tensile specimens, plane tensile specimens and cross biaxial tensile specimens were calculated. In order to take into account the power generation performance and fatigue life of silicone rubber composites, the total energy density (PI ) was used to evaluate the comprehensive properties of the composites. The results showed that through the PI evaluation, the strain energy density (W) was the largest and the ratio of cracking energy density to W was the smallest under equibiaxial tension. Silicone rubber may have the best comprehensive properties under equibiaxial tension.

The electrical contact is a pivotal component in the power transmission system, whose failure mode is closely related to the wear property of the coating on it.In this work, the silver coating was prepared by air supersonic flame spraying and cold spraying(CS).Subsequently, the reciprocating friction test was used to study the friction and wear properties of the coatings under different loads and frequencies, and the results were compared with the property of coatings fabricated by using electroplating.The scanning electron microscope(SEM)and X-ray energy spectrometer(EDS)were used to investigate the morphology and composition of the worn surface, and the friction and wear mechanisms of the coatings were analyzed and discussed.Results showed that both air supersonic flame spraying and CS processes could prepare thicker and denser silver coatings.The silver coatings prepared by cold spraying presented higher microhardness, smaller friction coefficient and lower wear loss under the high frequency and high load conditions.Besides, the wear mechanism of silver coating prepared by air supersonic flame spraying and CS was mainly fatigue wear.

This study is to elucidate the prevalence of multi-component mycotoxins in maize from clients in 2020 by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS).The maize samples in this study were prevalence of masked mycotoxins and emerging toxins. For the masked-Mycotoxins, most of samples were failed to be tested out. The D3G & 15-ACDON in some samples are the most prevalence which are at the level of 92.3% and 64.4%, for the emerging Mycotoxins, the beauvericin and moniliform in a few of samples are the most prevalence that are at the level of 96.69% and 95.03%. Through the analysis of these data, this paper aims to provide reference and guidance for the control of masked mycotoxin and emerging toxin.

BackgroundAirborne gamma spectrometer is a method to measure ground gamma nuclide activity (specific activity) by installing gamma spectrometer on aircraft. The accuracy of results is affected by flight altitude and terrain fluctuation. At present, altitude correction has been applied to the quantitative analysis of airborne gamma spectrometer, but the correction effect of altitude correction on areas with large terrain fluctuation is not desirable.PurposeThis study aims to propose a 3D terrain correction method based on discrete integral.MethodsFirst of all, the basic characteristics of digital elevation model (DEM) and radiation field distribution were analyzed. Then, the effective detection area of airborne gamma spectrometer was divided into micro grid surface elements, and the contribution of micro elements to the counting rate of full energy peak of the airborne gamma spectrum was calculated. The terrain correction coefficient by discrete integral was realized by the terrain correction of airborne gamma spectrum measurement results, and the accuracy of airborne gamma spectrum measurement results was simultaneously improved. Finally, verification of this method was performed on the measured airborne gamma-ray spectrum data processing.ResultsVerification results show that the influence of terrain on gamma spectrum data is corrected effectively by the proposed method.ConclusionsThe 3D terrain correction method based on discrete integral can improve the consistency between airborne gamma spectrum measurement results and ground measurement results, and has the advantages of fast mesh division, altitude and terrain correction simultaneous.

BACKGROUND Metal activity state measurement method is one of the effective means to find hidden ore. However, during the application of the method, it was found that the types of effective activity states of gold in different geochemical landscape conditions were not the same. Moreover, it was found that the conditions such as solid-liquid ratio, temperature and time during the extraction would have a significant impact on the active state extraction data. OBJECTIVES To solve the problems of selective extraction and accurate determination of the active state of gold. METHODS A comparative study of different experimental conditions and samples of different grain sizes for the active state extraction of gold from the Wangjiaping gold deposit in the Qinling area using ICP-MS analysis. RESULTS The optimal extraction conditions for gold element water extraction state, clay adsorption state, organic binding state and iron manganese oxide state were determined. Solid-liquid ratio was 1:5, the extraction time was 24h, the extraction temperature was 35℃ and the sample size range was -80 mesh. The method detection limits for the four phase states of elemental gold were 0.03ng/g for water extraction state 0.03ng/g for clay adsorption state, 0.04ng/g for organic binding state, 0.05ng/g for iron manganese oxide state. The relative standard deviation (RSD) was 7.25%-9.02%. In the 23rd line of the Wangjiaping gold deposit, the average content of the water extracted state gold was 0.19×10-9, the average clay adsorption state gold was 0.30×10-9, the average organic binding state gold was 11.16×10-9, and the average iron manganese oxide state gold was 0.20×10-9. CONCLUSIONS The organic binding state is the main active phase state of gold in the soil of the mining area, and the abnormality of the organic binding state of gold is consistent with the position of the hidden gold ore body.

The flattening machine made the aluminum strip perform repeatedly stretch bending deformation before cold rolling process. The flattening process has a vital influence on strip rolling process by improving plate shape and residual stress distribution of the strip in the same time. In this paper,the flattening process was researched by finite element method software Abaqus according to a five roll flattening machine. In order to describe behaviors and principles of the flattening process,a series of new definitions and descriptions were put forward. Based on numbers of simulation of different kinds of shape defects and systemic analysis,relations between the effect of flattening and different degrees of plastic deformation were discussed. The results show that the best flatness parameter is decided by the shape of itself.

In order to study the dynamic law of the quality change in low temperature yogurts,yogurts were stored at temperatures of 4 ℃,15 ℃,25 ℃ and 30 ℃ respectively,and the changes in protein level,fat level,acidity level,particle size,color,texture and total number of colonies were observed.The regression equation analysis shows that the changes of a* redness value (at 15℃,25℃ and 30 ℃),total color difference ΔE,colony number (at 4 ℃,15 ℃ and 25 ℃),softness and consistency (at 15 ℃ and 25 ℃)match the Zero-order kinetic model,while the changes of titratable acidity and b* yellowness value match the First-order kinetic model.The established shelf-life prediction model equation provides insights in the adjustment of storage and transportation conditions of low-temperature milk products,as well as quality monitoring during the storage period.

In this paper, the nutritional composition, active ingredients, and digestibility of malt roots were measured and analyzed and compared with those of wheat bran.The results showed that the content of protein(34.3%) and dietary fiber (39.4%) in malt roots are higher than those in wheat bran.The content of essential amino acids (8.37 g/100 g) is twice than that of wheat bran (4.03 g/100 g).The content of lysine, threonine and valine are relatively high in malt roots.Additionally, malt roots not only contain vitamin E (3.14 mg/100g),but also have a higher content of vitamin B2, B6 and B12, folic acid, and vitamin C than those in wheat bran(0.6 mg/100 g, 0.46 mg/100 g, 0.11 μg/100 g, 0.17 mg/100 g, 4.35 mg/100 g, respectively).Furthermore, the malt roots are rich in sodium, potassium, calcium, zinc, copper, phosphorus, iron, and magnesium.It also contains a high content of total polyphenols (1.09%) and a small amount of polysaccharides.At the same time, the regulatory status, application status and application prospect were analyzed from the feed, food and cosmetics fields, which provided a basis for the high-value utilization of malt root by-products.

In this study,by measuring the white light interference images,scanning electron microscope pictures and whiteness,transmittance,fine whiteness,L value,a value and b value of japonica rice with different bran degrees,the changed of japonica rice appearance and characteristics were studied.Studies showned that the grain cortex on both sides of the rice grain is ground first,and the abdomen and back of the rice grain are difficult to grind; the surface roughness increases first and then decreases with the bron degree;Aleurone layer and endosperm cell structure,as the decreases of bran degrees,are milled layer by layer; the whiteness,permeability,fine whiteness and L value of the sample are gradually increased,and the a value and b value are gradually reduced.

The riverbank collapse poses a serious threat to the safety of urban areas and critical infrastructures along the Yangtze River. At present, the commonly used monitoring techniques expose some problems, such as limited parameters and low monitoring frequency. To improve the effectiveness of river-bank collapse monitoring and early warning, a real-time monitoring approach based on weak fiber Bragg grating (WFBG) technology is introduced. This method employs weak fiber brag grating sensors as measuring units, and then utilizes time-division/wavelength-division hybrid multiplexing demodulation techniques together with some relevant conversion formulas to distinguish groundwater flow velocities under active heat source. A real-time monitoring system of riverbank collapse site can be set up for collecting multiple parameters simultaneously, including strain, temperature, displacement, flow velocity, and so on. We analyzed the monitoring data of WD02 borehole, which was located at the Zhinan Village riverbank collapse site in Yangzhong City. The results showed that there were two abnormal flow velocity zones at the depth of 20-30 m and 62-80 m, where the follow velocities reached 2.98x10-6 m/s and 3.4X10-6 m/s, respectively, nearly twice of the values observed in adjacent layers. Consequently, it is necessary to pay more attention to these two abnormal zones. Typical practice case shows that this technology has the advantages of accurate positioning, abundant data collecting and real-time monitoring even under extreme weather conditions. This research provides a cutting-edge and reliable alternative solution for the monitoring and early warning of riverbank collapse disasters. [ABSTRACT FROM AUTHOR]

The thermal insulation properties of nano-porous thermal insulating materials largely depend on thermal transport via gas phase within their pores, and this process relies on their pore structures. Therefore, investigating pore structures and thermal transport via gas phase is important to understand the heat transfer mechanism. Current research mainly focuses on the theoretical calculation and analysis from the perspective of heat transfer, and special and systematic studies based on actual materials have not been reported yet. In addition, accurate analysis of pore structures using usual techniques is difficult due to the complex pore network and the poor mechanical properties of their solid skeleton. In this study, nano-porous thermal insulating materials with different pore structures were synthesized via a sol-gel process followed by supercritical drying. The materials were then characterized by thermal conductivity tester, nitrogen adsorption-desorption, and helium pycnometer. The pore structures of the resulting materials were obtained, and the relationship between pore structures and thermal transport via gas phase was studied. Results show that the bimodal distribution of pores in the resulting materials, corresponding to gas-contributed thermal conductivity. All pores within the resulting materials can be equivalent to pores with a single diameter when the equivalent size of large pores is 10 times less than that of small pores. Similar to the pure gaseous thermal conductivity, the intrinsic gas-contributed thermal conductivity including gas-solid coupling effects rises with increasing pore diameter of the materials. The ratio of intrinsic gas-contributed thermal conductivity to pure gaseous thermal conductivity is 2.0, 1.5, and 2.0-1.5 for pores smaller than 200 nm, larger than 500 nm, and with size between 200 and 500 nm, respectively. When the equivalent size of large pores is 10 times less than that of small pores or when the equivalent size of large pores is 100-1000 times that of small pores and the contribution of large pores to the total porosity is less than 10%, the gas-contributed thermal conductivity reduction of the resulting material with decreasing gas pressure can be divided into three stages (steep decreasing stage, slow decreasing stage, and hardly changing stage) according to decreasing rate. When the equivalent size of large pores is 3000 times larger than that of small pores, the gas-contributed thermal conductivity reduction of the resulting material with decreasing gas pressure can be divided into four stages (steep decreasing stage, slow decreasing stage, steep decreasing stage, and hardly changing stage) even if the contribution of large pores to the total porosity is very low (less than 10%).

The performance of combustion of ventilation air methane (VAM) over transition metal oxide oxygen carriers was studied through experiments with using tube reactors. The results show that the activity of activated oxygen carriers in converting CH4 to CO2 is as follows:CuO60/γ-Al2O3 > NiO60/γ-Al2O3 > Fe2O360/γ-Al2O3. CH4 conversion based on CuO60/γ-Al2O3 decreases with increasing gas hourly space velocity, but increases with increasing bed temperature and CuO loading. The lower the initial CH4 concentration of ventilation air methane, the lower is the temperature for the CH4 conversion of 90%. There are catalytic combustion mechanisms and chemical-looping combustion mechanisms for CH4 combustion over both CuO60/γ-Al2O3, for which dispersion of the active component is low but loading is high, and CuO5.5/γ-Al2O3, for which dispersion of the active component is high but loading is low. There exists a maximum for CH 4 conversion based on the catalytic combustion mechanism at some temperatures, and when the bed temperature is higher than this temperature, the contribution of chemical-looping combustion is greater than that of catalytic combustion. The initial activity of CuO5.5/γ-Al2O3 is higher than that of CuO60/γ-Al2O3, while the stability of CuO60/γ-Al2O3 activity is better than that of CuO5.5/γ-Al2O3 activity under the same conditions.

Lower Silurian sandstone of the Xiaoheba formation in Southeastern Sichuan has a good reservoir seal combination, and an oil and gas geological condition, but the hypothesis that the sedimentary environment belongs to continental or marine sedimentary deltas remains a matter of debate. In order to solve this problem, 74 samples were collected from 9 typical sections. The elemental composition was determined by the trace element ratio method. Combined with the tectonic background and source characteristics, the sedimentary and paleoclimatic environment were discussed. X-ray Fluorescence Spectrometry (XRF) was used to analyze Ba, Mn, Sr, Cu and other trace elements, which are useful in discriminating between the sea and land facies sedimentary environment. The results show that the average Sr/Ba value is 0.2790 with the maximum of 2.31, the Mn/Fe value is 0.0093 to 0.0778, and the Sr/Ca value is 0.0005 to 0.0414, typical of freshwater delta sedimentary characteristics. The average Sr/Ba is less than 1, the average Sr/Cu is 4.8758, and more than 8.1% samples have Sr/Cu values greater than 10, reflecting the warm, moist, ancient climate environment.

To solve the breeding problem of the serious shortage of female cassava flowers, cassava variety 'Xinxianxuan 048' was used as the experimental material. Transcriptional sequencing technology was used to analyze the biological information of differentially expressed genes in female and male flowers during the critical period of cassava flower sex differentiation, explore the functions of differentially expressed genes and possible regulatory pathways involved, excavate candidate genes related to female differentiation, and verify the sequencing results by qRT-PCR method. The results showed that: There were 545 differentially expressed genes between male and female cassava flowers at the critical stage of gender differentiation. Among them, 48.63% of the differential genes were enriched in GO pathway of floral organ morphogenesis and development, and the genes enriched in plant phenylpropanol biosynthesis and plant hormone signal transduction were the most. AGL11, YABBY4, CRC, SUP, and other flower sex differentiation genes were significantly up-regulated in female flowers. Four genes of the cytokinin signaling pathway, including HK4, HPt4, ARR8, and ARR12, were significantly up-regulated in female flowers, while IAA14, GH3, SAUR22, and SAURR20, the early auxin response genes, were significantly down-regulated in female flowers. Therefore, the sexual differentiation of cassava flowers mainly involved the biological pathways of pollen, gametophyte, floral organ morphogenesis and development, and two metabolic pathways of plant phenylpropanoid biosynthesis and plant hormone signal transduction. Cytokinin and auxin might be the main hormones in cassava female flower differentiation. AGL11, YABBY4, CRC, SUP, HK4, HPt4, ARR8, and ARR12 may be positive regulators of cassava female flower differentiation. [ABSTRACT FROM AUTHOR]

The plant height, stem diameter, fresh weight, dry weight, crude protein (CP), neutral detergent fiber (NDF) and acid detergent fiber (ADF) of five oat varieties introduced and planted in saline-alkali land of Songnen Plain after spring sowing were measured, and the correlation research was carried out to evaluate the production adaptability of different oat varieties in Songnen Plain. The results showed that the plant height, fresh weight and dry weight of Wild horse were 121 cm, 5 534 kg/hm² and 1 707 kg/hm², respectively. The RFV of Pak Yin NO. 2 was higher than those of other varieties, reaching 113. The study indicates that the yield of oat variety Wild horse is higher than that of other varieties, and the RFV value of Pak Yin NO.2 is better. These two varieties are more suitable for planting in this area. [ABSTRACT FROM AUTHOR]

A primer of the bismaleimide resin toughened with block copolymer was prepared. The properties of the primer, such as adhesion, pencil hardness, impact resistance, environment resistant, ageing resistant performance and etc. meet the requirements of the technical specifications of GJB1388. The thermal property of the primer was characterized by differential scanning calorimeter (DSC), thermal gravity analysis (TG), and dynamic mechanical analysis (DMA). The results show that the primer possesses good heat resistance, the glass transition temperature of the primer reach 238℃, 5% mass heat lost temperature is 384℃ after 200℃ cured, and the glass transition temperature of the primer reach 268℃, 5% mass heat lost temperature is 407℃ after 230℃ heat treatment respectively. Bonding strength will increase when the bismaleimide primer doubled with bismaleimide film adhesive, when the primer doubled with J-188 bismaleimide film adhesive, peel strength increases to 107%, the room temperature shear strength and high temperature shear strength increase by 10%.The primer can also be used with other bismaleimide film structural adhesives, which are suitable for the bonding between metals or bismaleimide composites with metals.

A wind tunnel of high temperature and long operation time requires the use of cooling techniques,so we need design cooling channels on the nozzle. In this paper,rectangular cooling channels of high cooling efficiency were used to study the factors affecting nozzle cooling. First of all,a three-dimensional model of nozzle cooling structure was established. Secondly,the type of heat transfer of the nozzle was detailedly analyzed and at the same time radiation heat transfer was taken into account. Then based on the principle of simplicity and accuracy,a series of assumptions were made for the calculation model. Finally CFD techniques were used to carry out the numerical simulation. By analyzing the results of study,we obtained the rules how the aspect ratio of cooling channels influenced nozzle cooling,the difference whether or not considering radiation heat transfer,and the impact of gas flow total temperature on nozzle cooling.

For problem that shearer on fully mechanized coal face has lower positioning accuracy, a shearer positioning method using strapdown inertial navigation system based on Rodrigues parametric method was proposed. The tri-axial accelerometer and suspended gyroscope in the SINS were used to output information of acceleration and angular velocity of the shearer, and Rodrigues parametric method with no-redundancy was applied to calculate the position and attitude data. The simulation result shows that in the process of beveling feed, the maximum positioning error is 0.291 4 m and the maximum error of attitude angle is 0.602 2 °, it meets the requirements of positioning accuracy of shearer.

[Objectives] Buoyancy regulating system is a key component of an underwater glider for controlling submerging and surfacing statuses and gliding speed of the underwater glider. To further study the buoyancy regulating system,[Methods] we carry out theoretical analysis and CFD for the underwater glider and its buoyancy regulating system to obtain the buoyancy regulating value,which is an important design parameter;develop a buoyancy regulating system with both oil outlet and oil return passages,that is,a high-pressure plunger pump for oil outlet in deep water and a low-energy gear pump for oil return in shallow water. We conduct the tests for the oil outlet and oil return characteristics and the energy consumption under different pressure conditions.[Results] The results show that the oil outlet is normal under the pressure of 2.5 MPa and the oil return is normal under atmospheric pressure. The developed test device can simulate the marine pressure in the actual operating environment of the underwater glider.[Conclusions] The study results can provide useful references for the engineering application of the buoyancy regulating system.

The recovery of iron-bearing silicate minerals is a key on the re-separation middlings of Anshan type lean magnetite,but this recovery process should be conducted selectively. The iron grade of stage 1 tailing is only 3.92%,so there is no need to recover it. However,the iron grade of stage 2 tailing is 34.51%,thus this tailing can be returned to the mixing process before direct reduction and its iron is indirectly recovered. Under the condition of the direct reduction temperature of 1150℃,the direct reduction time of 45 min,the limestone dosage of 16% and the coal dosage of 12%,the optimum TFe and εFe obtained from closed-circuit experiment is 92.69% and 91.17%. Iron and silicon in the iron-bearing silicate are reduced to elemental iron and reengineered to aedelforsite,respectively.

In view of problem of traditional leakage detection method of DC power supply system in overhead line system that it has detection dead zone and big voltage deviation between bus and ground, a new kind of leakage detection method based on balancing bridge method and switching bridge method was proposed. Detection principle of the method was analyzed and computational model of balancing resistors and switching resistors were established from the perspective of lowering voltage deviation between bus and ground. The Simulink simulation results show that the new method can reduce voltage deviation between bus and ground, and improve stability of the power system.

In view of the problems of high energy consumption, poor ecological restoration and rational utilization of waste concrete in the practical application of acid mine wastewater treatment methods. Based on the water purification characteristics of pervious concrete, waste concrete, cement and other materials are used to develop water purification reclaimed aggregate pervious concrete (ZSCR), combined with diatomite and swelling. The performance and practical application prospect of different ZSCR were studied by modifying the clay and red mud. The recycled aggregate and ore were analyzed by XRD, SEM and other testing methods, Effect of material admixture on its water purification performance. The results show that: compared with ordinary pervious concrete, recycled aggregate has less influence on the water purification performance of pervious concrete. The water purification performance of ZSCR was obviously enhanced after the modification of the admixture. The addition of diatomite and other materials improved the pore structure of the specimen and produced a lot in the gel layer. The unhydrated mineral phase gel particles enhanced the adsorption performance of ZSCR to heavy metal pollutants. When the hydraulic retention time is 12 h and the red mud content is 30%, the red mud reclaimed aggregate pervious concrete can effectively intercept heavy metal ions in surface water of mining area, it can be used as reaction medium in water ecological restoration technology such as constructed wetland and biological filter to treat acid mine wastewater. [ABSTRACT FROM AUTHOR]

Probiotics are living microorganisms that are added to feed as supplements or additives. Probiotics can improve production performance of broilers, improve intestinal morphology, improve meat quality, regulate intestinal flora and improve feeding environment of broilers. The paper mainly reviews the probiotics commonly used in poultry production and their mechanism of action, summarizes the influence of probiotics added in diet on broilers production performance, to provide reference for further application of probiotics in broilers production. [ABSTRACT FROM AUTHOR]

A monitoring and fault diagnosis system for shearer based on NI CRIO embedded platform and LabView development platform was constructed, main functions and design of hardware and software of the system were introduced in details. The system not only can real-timely monitor, control state of movement device of the shearer, and make over-threshold alarm, and can real-timely store monitored parameters and fault information, so as to analyze running status of shearer by technician, but also can real-timely display vibration signals of the shearer, and can filter, analyze time-domain, cepstrum and power spectrum, so as to implement fault diagnosis function before delivery and in maintenance process, which is helpful to locate fault for shearer.

In view of problem that power coefficient must keep maximum value when wind power system is in underpower stage, the paper proposed a control strategy of maximum power point tracking based on wavelet neural network and PID controller. The strategy uses wavelet neural network to make online identification for power coefficient and returns sensitivity information after ending of one identification period. PID controller adjusts PID parameters according to the sensitivity information. Simulation result shows that wavelet neural network and PID controller improves blade top speed ratio, power coefficient and output power of wind power system and reduces response time compared with common PID controller, which realizes optimal running of wind turbines.

In view of problems of expensive and inconvenient to wear of existing active anti-noise earmuffs, an active anti-noise earmuff in heavy noise environment was designed. The earmuff takes TMS320VC5509 as processor, and adopts adaptive noise cancellation method and the normalized least mean square algorithm to enhance adaptive noise cancellation performance. Combined with passive noise reduction technology, the earmuff realizes purpose of noise cancellation in heavy noise environment. The experimental results show that anti-noise performance of the earmuffs is up to 30 dB.

In view of electrical energy waste problem of belt conveyor in a Coal Mine, a electrical energy-saving control system with frequency conversion speed regulation for belt conveyor was designed. The system uses BP neural network to build energy-saving model of coal flow, belt speed and power consumption of belt conveyor, uses genetic algorithm and neural network to optimize the model parameters to get the best matching relationship between the coal flow and belt speed, uses fuzzy control algorithm to realize energy-saving operation of belt conveyor with frequency conversion speed regulation. The practical application shows that the system can regulate speed of belt conveyor according to coal flow and reduce machine loss, and energy saving effect is notable.

The paper analyzed principle of ultrasonic ranging and its main error causes and put forward an error compensation algorithm of ultrasonic ranging based on BP neural network. The algorithm trains samples of given input vector and target vector, and adjusts weights and threshold in process of training constantly, so as to reach a mapping relationship to correct error. The simulation result verified effectiveness of the algorithm.

For the problems of vehicle scheduling system of open-cut based on GPS,such as high energy consumption of user node,big volume and high cost and need fixed infrastructure, the paper discussed on feasibility of applying WSN in vehicle scheduling system of open-cut. It analyzed key technologies used in vehicle scheduling system of open-cut based on WSN, pointed out the positioning technology is a precondition of applying WSN in vehicle scheduling system of open-cut successfully, and introduced a positioning algorithm which is adapted to vehicle scheduling system of open-cut and implementation method of target positioning. Finally, it gave application prospect of the system.

The paper analyzed principle of mechanical system of crawler travel system, and used multi-body dynamics software of RecurDyn to do simulation and analysis of walking state on flat road with soft soil of virtual prototype of compound obstacle crossing robot with master-slave track. The simulation results show that the gravity center of the prototype does not coincide with the geometric center, which leads down track of guide wheel to sink lower than other tracks, while the uneven pressure distribution may lead to locally grounding of track and reducing track life. So the rational allocation of gravity center of prototype should be paid attention to during design.

Big data storage plays an important role in the whole big data application framework system in view of the increasing amount of data. Performance evaluation for big data storage can guide big data application developers to analyze performance bottlenecks and optimize the performance of big data systems. In the past, benchmarking was usually used to evaluate the performance of different big data frameworks, or the performance analysis of distributed file systems was carried out by piling and analyzing track files. These two methods adopt different analytical perspectives, but there has not been a reasonable evaluation system to evaluate the distributed storage system of big data. This paper proposes the architecture and specific implementation of the big data storage performance evaluation method combining active and passive methods. In the active evaluation method, this paper provides benchmark test programs of more than 20 applications in 6 fields to initiate performance tests on big data storage systems, and analyzes the benchmark performance indicators of big data storage systems. In the passive performance evaluation method, this paper provides analysis and positioning methods for inefficient tasks, inefficient operators and inefficient functions. By analyzing the big data applications running on the big data storage systems, we can find out the reasons for the inefficiency of big data applications. Experiments show that the architecture of the proposed big data performance evaluation method can comprehensively evaluate the performance of big data storage. [ABSTRACT FROM AUTHOR]

The experiment was to investigate the effect of different shapes of feed on foraging behavior of breeding pigeons. In the experiment, healthy American white-feathered king pigeons with similar body weight were used as research subjects and were divided into three experiments. Experiment one: 40 pairs of pigeons with complete production records were selected and divided into two groups, namely, picky eaters and non-picky eaters, to compare their performance from January to April. Experiment two: 10 pairs of non-brooding breeders were selected to be fed a mixture of four shapes of corn embryonic, spherical, oval and cylindrical. The feeding behaviour of the breeding pigeons was observed. The test period was 14 d. Experiment three: 32 pairs of non-brooding breeders were randomly divided into four groups, with eight pairs in each group, the pigeons were fed with above four kinds of feeds, respectively. The feeding behaviour of the breeding pigeons was observed. The test period was 14 d. The results showed that compared with non-picky type, the survival rate of the squab reared by the picky type from January to April was significantly lower (P<0.05). From 0 to 10 min, pigeons preferred corn embryonic or cylindrical feeds. From 10 to 15 min, pigeons fed corn embryonic feed was extremely more than spherical feed (P<0.01). Within 20 min, pigeons fed corn embryonic or cylindrical feeds extremely more than spherical or oval feeds (P<0.01). The waste amount of corn embryo feed was extremely higher than that of other shapes (P<0.01). The feeding time of oval feed was extremely higher than that of other shapes (P<0.01). The experiment indicates that cylindrical feed can be used to increase feed intake and reduce feed waste of pigeons in practical production, trying to reduce the negative impact of the picky feeding behavior. [ABSTRACT FROM AUTHOR]

With the development of cloud computing, deploying workflows onto cloud computing platforms has become a popular choice. Compared with the traditional local workflow, cloud workflow not only needs to consider the requirements such as the execution time, but also considers the economic cost. In order to improve the resource utilization, cloud computing service providers provide spot instances, which are very cheap but unstable. Aiming at the problem of workflow scheduling and execution in cloud computing, this paper proposes a spot instance configuration and scheduling method that meets the workflow execution time budget. This method uses Markov models and dynamic programming methods to predict the price of spot instances and obtain the lowest cost bid strategy. At the same time, to satisfy the execution time budget of the workflow, the instances used in the workflow are configured under the estimated bid strategy. Experimental results show that, compared with using on-demand instances, our method can save up to 89. 9% computation cost, while meeting the workflow execution time budget. [ABSTRACT FROM AUTHOR]

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Let n be positive odd numbers without square factor, the distribution of solutions on the integer points on the elliptic curve y² =nx (x² +256) is studied by using properties of congruence, Legendre symbol value and the methods of elementary number theory. It is proved that the above elliptic curve equation has two integral points (x, y) = (0, 0) and (x, y) =(12,120) if n = 3, and it has only one integer point (x, y) = (0, 0) if n ≠ 3. [ABSTRACT FROM AUTHOR]