Search

Fatty acids in oat flour have been analyzed by using multiple reaction monitoring mode of gas chromatograph-mass spectrometer. The samples and fatty acid standards were methylated by potassium hydroxide - methanol and boron trifluoride- methanol solutions for 15 min to produce the corresponding fatty acid methyl ester. Then, the products would be separated through DB-FastFAME (90 m×0.25 mm×0.25 μm) capillary column. Multiple reaction monitoring mode (MRM) was performed under electron bombardment ionization (EI) source, and the external standard method was carried out for quantitative analysis. 40 kinds of fatty acid methyl esters could be completely separated within 38 min. A good linear relationship was achieved in the concentration range of 0.4~40 μg/mL. The correlation coefficients of standard curve were all greater than 0.999 7. The limit of quantification of 6 fatty acids such as C20:2 was 0.003 g/100 g, and the remaining 34 fatty acids was 0.000 6 g/100 g. The standard recoveries of fatty acids were 86.6%~107.3%, and the precision was between 0.9% and 5.2%. It is a method for simple operate and high selectivity, which has a good accurate, precise and sensitive. The method is suitable for the rapid and accurate determination of fatty acids in oat flour.

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.

Objective： This study aimed to explore the fatigue relieving effect of Lonicera caerulea Berry polyphenol, hawthorn polyphenol microcapsules, lactoferrin and vitamin C as polyphenol compound formula to alleviate fatigue. Methods： The commercial sports nutrition food with the compound formula of creatine, β-hydroxy-β-methylbutyrate, fructose diphosphate, taurine, vitamin B6 and watermelon powder was used as the positive control. The experiment of exhaustive swimming in mice was carried out. The fatigue related indexes were determined by the kit, and the microscopic pathological tissues of the organs were observed by H&E staining. Results： There was no significant difference in body weight of mice (P＞0.05). Compared with the normal group, no significant difference in organ index in the dietary supplement group (P＞0.05) was found. Polyphenol compound formula significantly prolonged the swimming time of mice at room temperature and low temperature by 106.01% and 140.94%, respectively (P＜0.01). Moreover, oxidative stress, metabolite accumulation and energy metabolism, and down-regulated secretion of inflammatory factors (P＜0.01 or P＜0.05) were also improved. It promoted the cell nucleus increase in muscle, inflammatory cell infiltration in the liver, and redness and shedding of tubular epithelial cells in the kidney. Conclusion： Polyphenol compound formula can relieve exercise fatigue at low temperature and room temperature.

In severe operating conditions of spent fuel reprocessing plants, such as strong acid and high temperature, equipment corrosion problems are common. The corrosion problems/incidents in Japanese reprocessing plants and some relevant experimental research, evaluation and investigation work carried out by Japanese institutions and scholars were summarized in this paper. The related research results and experience from Japan will provide our country with some reference and technical basis for the design and manufacture, life prediction, preventive maintenance of key equipment, periodic safety evaluation of reprocessing facilities, etc.

Objective To investigate the relationship between solid pulmonary nodules with maximum diameter≤2 cm and the bronchi in order to provide more valuable clues to differentiate benign and malignant solid pulmonary nodules. Methods The clinical and CT data of 776 patients with solid pulmonary nodule at a maximum diameter of not larger than 2 cm confirmed by pathology in our hospital from January 2014 to January 2021 were analyzed retrospectively. According to pathological types, the patients were divided into malignant nodule group(n=340) and benign nodule group(n=436), and those with benign nodules were further assigned into inflammatory nodule subgroup(n=299) and benign tumor subgroup(n=137). Bronchogram sign on CT images were classified into 4 types according to the relationship between pulmonary nodules and bronchi. The incidence and types of different bronchogram sign on CT images were compared between malignant nodule group and benign nodule group, and between inflammatory nodule subgroup and benign tumor subgroup. The diagnostic performance of bronchogram sign on CT images to differentiate benign and malignant solid pulmonary nodules was evaluated. Results ① The incidence of bronchogram sign on CT images was higher in the malignant nodule group than the benign nodule group(65.9% vs 31.4%, P < 0.001). Types Ⅰ and Ⅱ signs were more common in the benign nodule group, while Types Ⅲ and Ⅳ signs were more common in the malignant nodule group(all P < 0.01). The sensitivity, specificity, and accuracy of bronchogram sign on CT images was 82.1%, 56.2%, and 72.3%, respectively in differentiation of benign and malignant solid pulmonary nodules. ②The incidence of bronchogram sign on CT images was statistically higher in the inflammatory nodule subgroup than the benign tumor subgroup(39.1% vs 14.6%, P < 0.001). Type Ⅳ was more common in inflammatory nodule subgroup(P < 0.05). However, no significant differences were observed in the other 3 types between the 2 subgroups (all P > 0.05). Conclusion Bronchogram sign on CT images is valuable in differentiation of benign and malignant solid pulmonary nodules measuring ≤2 cm in diameter. Irregular air bronchogram sign or truncation of bronchus in the margin of nodule is highly suggestive of malignancy.

Aileron stiffness simulator is a device to simulate the support stiffness of aileron actuator,which is a key device in airplane ground test. The research on the stiffness simulator is beneficial to its design and application,and has important engineering value. In this research,in order to establish the mechanical model accurately,the stiffness reduction factor is proposed. And the correctness of the mechanical model and simulation is verified through the stiffness test. Lastly,the thickness of the simulator is optimized based on the sensitivity of the target stiffness with distance. The results show that the stiffness reduction factor can be used to quickly predict the stiffness,and 7 mm is the optimal stiffness plate thickness of the simulator.

Objective To investigate the effect of ADAM17 on proliferation of cervical cancer cells in vitro and its mechanism. Methods The specific shRNA against ADAM17 was transfected into HeLa cells. Western blot and RT-qPCR were used to examine the interference efficiency. The relative rates of proliferation were determined by CCK-8 assay. The migration and invasion were evaluated by scratch test and Transwell test.Western blot was used to detect the protein expression of PCNA, EGFR, p-EGFR, ERK and p-ERK in each group. Results The expression of ADAM17 mRNA and protein were decreased in HeLa cells transfected by sh-ADAM17(P＜0.05).ADAM17 had no effect on migration and invasion of cervical cancer cells,but ADAM17 interference significantly inhibited the proliferation of cervical cancer HeLa cells(P＜0.05). The expression of PCNA, p-EGFR and p-ERK protein was down-regulated(P＜0.05). Conclusions Interfering with ADAM17 can inhibit the proliferation of human cervical cancer cell line HeLa, which may be related to EGFR/ERK signaling pathway.

Multi-line lasers were applied to the on-line defect detection for steel rails instead of single-line laser,which solved the problem of "pseudo defects" due to the vibration of rails under the mode of single-line laser. Images of multi-line lasers captured by camera were processed to realize the online detection and the accurate defect feature area was acquired with steps of the extraction of strip centers,detection of difference algorithm,discrimination between real and pseudo defects,image mosaic,etc. Images of the defect area were extracted by the cross-correlation and self-correlation information of laser curves,and there was no need for the step of depth mapping under the single-line mode,so the problem of "fault detection" caused by the vibration of rails was solved fundamentally. The technique is applied to on-line detection of defects for the bottom side of steel rails,and the detection rate is much higher than manual detection.

W18O49/C-TiO2 direct Z-scheme photocatalyst was prepared by a simple hydrothermal method. The structure, morphology, transport properties of photogenerated carriers and energy band structure were characterized by XRD, SEM, TEM, HRTEM, PL and other measurements. Under simulated sunlight illumination, the photocatalytic water splitting performance for hydrogen (H2) production and quantum efficiency were studied without adding any sacrificial agent. The results show that the construction of W18O49/C-TiO2 direct Z-scheme photocatalyst can significantly improve light absorption, accelerate the separation and transport of photogenerated carriers, and enable more photogenerated electrons participate in the photocatalytic reduction reaction, so the sample possesses high efficient photocatalytic activity. The photocatalytic H2 production tests show that under simulated sunlight illumination, the W18O49/C-TiO2 direct Z-scheme heterojunction can achieve H2 production rate of 209 μmol·h-1·g-1 without adding any sacrificial agents. It also exhibits strong photocatalytic stability; the H2 production remains unchanged during the 24 h cycle test.

A new application of baking soda was developed, the synthetic colorant in cereal was extracted by adding with methanol solution in this paper.To develop new uses of edible bicarbonate,synthetic colorants were extracted from cereals by adding methanol water solution of edible bicarbonate in this paper, Ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS)was used to test standard recovery.The extraction effect of edible bicarbonate of soda on five synthetic colorants of sunset yellow, amaranth red, carmine red, alluvium red and bright blue in cereals was investigated.The sample was extracted with 70 mL 40% methanol water vortexed with 1g edible baking soda, purified with Strata X-AW SPE column and determined.The results showed that, a good linearity was observed between 0.1 and 1.4μg/mL, and for the 5 synthetic colorants, the limit of detection was between 0.07 and 0.50 μg/g.The recoveries of the 5 synthetic colorants of different food substrates at different spiked levels (1, 2 and 10 μg/g) were all found to be in the recovery range specified in GB/T27404.The recoveries for the 5 synthetic colorants were found between 80.0% and 110% with RSD from 0.7% to 5.1% (n=6).Hence, baking soda added to 40% methanol water solution can be used to extract synthetic colorants from grain products with simple operation, accurate results, high efficiency and environmental protection.

Objective: The flavor formation process of stewed pork was investigated in this study. Methods: Electronic nose and gas-phase mass spectrometry （GC-MS） techniques were used to compare the key processes such as bleaching, frying, stewing and addition of sauces during the processing of stewed pork, and to analyze the changes of flavor compounds. Results: The results of electronic nose measurement were consistent with the results of gas chromatography analysis. The flavor content of raw pork and sauces was the highest, and the flavor substances decreased in the blanching, frying and stewing stages. However, the characte-ristic flavor substances were formed continuously. A total of 148 compounds were detected by GC-MS, including 39, 32, 23, 20, 38, and 65 compounds in raw pork, blanched, fryed, stewed and finished products and sauces, respectively, which mainly produced aldehydes and ketones, esters and alcohols, heterocyclic compounds, and aromatic hydrocarbons and their derivatives. The characteristic flavors of finished products were hexanal, benzaldehyde, 1-octen-3-ol, cinnamaldehyde, 2-pentylfuran, 2-acetyl pyrrole, 2,3-dimethyl-5-ethylpyrazine, etc. The content of acetoin was higher in the pre-preparation stage of stewed pork, while methoxy-phenyl-Oxime stayed high in all of the processes. Conclusion: The electronic nose technique can be used to detect the changes of flavor substances in different processing stages of stewed pork, but the specific substance changes need to be determined and analyzed by GC-MS.

Herein, the single-track and block samples of 24CrNiMo alloy steel were prepared by selective laser melting (SLM) technology and laser melting deposition (LMD) technology. The phase composition, microstructure, texture types and micro-hardness of 24CrNiMo low alloy steel under two laser irradiation conditions were studied. The results show that the main phase compositions of 24CrNiMo alloy samples prepared by two methods are α-Fe phase and a small amount of Fe3C.Furthermore, the grain orientation of SLM single-track deposited sample is random and disordered, and there is no obvious preferred orientation.However, the preferred orientation of LMD single-track deposited sample is the (110)〈101〉 plane texture. The grain of SLM block sample has weak 〈111〉 texture parallel to the deposition direction, LMD block sample has strong texture with the 〈111〉epitaxial growth orientation.Additionally, the main microstructure of as-built SLM sample is lower bainite, and the microstructure of as-deposited LMD sample mainly consists of lathbainite. The average micro-hardness SLM sample with fine grain and lower bainite microstructure is higher than that of LMD sample.

Among the manufacturing methods of high performance gradient functional materials, laser additive manufacturing technology can achieve the materials with gradient microstructure and property through precisely controlling the powder feeding and corresponding process adjustment, providing a new way to prepare high performance gradient functional materials more conveniently and efficiently. The basic principles and classification of laser additive manufacturing technology for high performance gradient functional materials were introduced in this paper, and the research progress in manufacturing high performance gradient functional materials by laser additive manufacturing technology at home and abroad was summarized. Furthermore, the shortcomings of this research field in material selection, process optimization and process monitoring were proposed, and its future research directions, such as the establishment of standard systems, in-depth theoretical research and the development of new manufacturing systems, were prospected, which provide guidance for the research of laser additive manufacturing technology for high performance gradient functional materials.

BACKGROUND The abundances and variation characteristics of silver, boron and tin reflect the regional metallogenic conditions and indicate the existence of deposits or mineralization. Silver, boron and tin in carbonate minerals are elements that must be determined in exploration geochemistry and multi-objective geochemistry. The analytical method was one of the essential methods in the matching analysis scheme of geochemical elements. Because carbonate minerals are different from common rocks, soils and water-based sediments, these minerals are mainly limestone, dolomite and other rock samples with relatively high calcium and magnesium elements, and the technical difficulty in determining silver, boron and tin in these samples is that the high content of calcium and magnesium matrix will seriously disturb the elements with low contents to be measured, and the sample is easily contaminated due to carbon dioxide during the spectrum recording process. OBJECTIVES To solve the problems of rapid and accurate determination of silver, boron and tin in carbonate minerals. METHODS In view of the particularity of carbonate minerals, an analytical method for the simultaneous determination of silver, boron and tin in carbonate minerals by alternating current-arc optoelectronic direct reading-optical spectrometry (AC-Arc-OES) was established. RESULTS By using 10% hydrochloric acid to digest the sample, the interference of matrix elements, calcium and magnesium, was eliminated. Germanium was used as the internal standard element for quantitative analysis, which eliminated the influence of external factors, such as the change of arc excitation conditions and matrix composition of the sample. The silver element and the long wave germanium element were used to form the analysis line pair, and the boron and tin element and the short wave germanium element were used to form the analysis line pair with good sensitivity. Twelve national geochemical reference materials, such as natural carbonate rock and synthetic limestone, were selected as the standard series. The matrix components were similar to those of the samples. The method of off-line subtraction was used to correct the background. The detection limits of the method for silver, boron and tin were 0.008μg/g, 0.49μg/g and 0.18μg/g, respectively. The precision of the method was larger than 10% for silver, and that of other elements was better than 10%. The accuracy of the method was verified by the national level geochemical reference materials, and the logarithm difference between the average value and the certified value of the reference materials was less than or equal to ±0.05. CONCLUSIONS This method was used to solve the problem of rapid determination of silver, boron and tin in carbonate minerals. It is simple and fast, and suitable for the determination of a large numbers of samples. All of the technical indices of the method meet the requirements of multi-objective regional geochemical survey specifications.

In order to improve the corrosion resistance and wear resistance of magnesium alloy efficiently and environmentally, the corrosion resistant and wear resistant coating were prepared on AZ91D magnesium alloy by direct electroless nickel plating without fluorine, chromium, cyanogen and zinc. The surface morphology, composition, phase and corrosion resistance properties were characterized and compared by SEM,EDS,XRD and electrochemical workstation respectively. The results show that the coatings are smooth and compact, consisting of fine and uniform cellular structure being mainly composed of 85.25%(mass fraction) amorphous Ni and P in the ratio of main salt to reductant is 1:1.4,complexing agent concentration is 16 g·L-1, pH=7 and the temperature is (85±0.5) ℃.The hardness is increased from 72HV of substrate to 285HV. Corrosion potential is enhanced from -1.524 V(substrate) to -0.513 V, meanwhile the corrosion current density is decreased by about 3 orders of magnitude. The cohesion between the substrate and the deposition layer is good without peeling and falling off, and the thickness of the deposition layer is approximately 38 μm.

The surface treatment was carried out on the surface of materials of A473M martensitic stainless steel axle sleeve by rolling technology, aiming to investigate the effect on its mechanical properties. The surface morphology and roughness, residual stress, microhardness, tensile and fatigue property were systematically studied using the SEM, white light interferometer, X-ray diffractometer, microhardness tester, EBSD, tensile tester and fatigue tester. The results show that the surface roughness of rolling specimen reduces significantly, which is about 1/5 of that of turning surface. The residual compression stress is induced near surface by rolling processing, the maximum value can reach up to 946 MPa and the residual compression stress decreases along with the depth. The thickness of the residual compression stress layer is about 200 μm. In addition, the rolling surface microhardness can be improved by 30% compared with that of turning surface and the hardened layer can be about 200 μm. As for mechanical properties, the tensile strength, yield strength and elongation of rolling specimens increase about 40%, 22% and 8% respectively compared with that of turning specimens. The fatigue life increases from 5.4×104 cycles to 1×107 cycles after rolling processing. The mechanical properties of the rolled material significantly improve, and the fatigue life significantly increases.

BACKGROUND Copper nickel and zinc concentrates all belong to metal sulfide minerals and are import commodities. The rapid and accurate analysis of dispersed elements in these samples is beneficial to the comprehensive utilization of mineral. However, the content of rare elements in such minerals is extremely low, and the properties of each element are different. In particular, Ge and Se cannot be precisely determined due to volatilization loss in wet digestion, and it is difficult to simultaneously measure various elements. OBJECTIVES To simultaneously determine the various elements in the sample. METHODS Copper, zinc and nickel concentrates were used as representative sulfide minerals. The sample was pre-sealed by microwave digestion, and the content of rare elements was determined by inductively coupled plasma-mass spectrometry (ICP-MS). Simultaneous determination of various elements was realized. The experimental conditions of total solid solution, internal standard, mass spectrum interference elimination and pretreatment acid selection were compared. RESULTS During determination of Ga, Ge, Se, Cd, In, Te, La and Tl by microwave digestion in ICP-MS analysis, total amount of solid solution, internal standard, and mass spectrum interference elimination conditions was consistent in three types of metal sulfide ores. Unfortunately, the acid types were not the same. HNO3-HCl-HF-H2O2 system was more suitable for measuring Ga, Ge, Se, Cd, In, Te, La and Tl in nickel and zinc concentrates, and Ga, Ge, Se, Cd, In, La and Tl in copper concentrate. The recoveries of these elements ranged from 85.5% to 116.6%. The HCl-HNO3 (3:1) system was more suitable for detecting Te in copper concentrate. CONCLUSIONS The method is simple, and the simultaneous determination of multiple elements is realized. Other factors of the method are the same, the acid digestion system is the key to selection.

The surface treatment was carried out on the surface of materials of A473M martensitic stainless steel axle sleeve by rolling technology, aiming to investigate the effect on its mechanical properties. The surface morphology and roughness, residual stress, microhardness, tensile and fatigue property were systematically studied using the SEM, white light interferometer, X-ray diffractometer, microhardness tester, EBSD, tensile tester and fatigue tester. The results show that the surface roughness of rolling specimen reduces significantly, which is about 1/5 of that of turning surface. The residual compression stress is induced near surface by rolling processing, the maximum value can reach up to 946 MPa and the residual compression stress decreases along with the depth. The thickness of the residual compression stress layer is about 200 μm. In addition, the rolling surface microhardness can be improved by 30% compared with that of turning surface and the hardened layer can be about 200 μm. As for mechanical properties, the tensile strength, yield strength and elongation of rolling specimens increase about 40%, 22% and 8% respectively compared with that of turning specimens. The fatigue life increases from 5.4×104 cycles to 1×107 cycles after rolling processing. The mechanical properties of the rolled material significantly improve, and the fatigue life significantly increases.

The open pipe pile is widely used because of its high bearing capacity, reliable quality, and convenient construction.The formation of the soil plug makes the total resistance of the open pipe pile different from that of the closed pipe pile. The bearing capacity of the open pipe pile includes three parts: the external friction of the pile, the pile end resistance, and the pile inside the friction. According to the stress characteristics of open pipe piles during installation, a self-developed large-scale laboratory test apparatus was used to test the penetration of open pipe piles under different forms of pile boots, and based on the results, the open pipe pile was compared with closed pipe pile. The results show that the open pipe pile tends to be occluded with the increase of pile depth. The resistance of pile increases linearly with the pile sinking process, while the frictional resistance inside and outside the pile has "lateral degeneration effect. "The influence range of surface displacement decreases with the increase of radial distance. The uplift rate gradually reduced with the increasing depth of pile sinking. The influence range of soil around pile is about 5 to 7 times of pile diameter. The pile shoe affects the height of the soil plug, pile resistance distribution, internal and external frictional resistance, and the effect ofpushing against soil. The pile of 30° inside pile boots has the largest height of soil plug formation, as well as the maximum friction resistance and the maximum proportion of total pile resistance. The amount of surface soil uplift around the pile is the smallest. The outer 30° pile boot is opposite to the inner 30° pile boot, while the right-angle pile boot is centered. The resistance, lateral friction, and soil compaction of closed-end pipe pile are greater than those of the open pipe pile.

BACKGROUND AnYe-1 well is a geological survey parameter well implemented by China Geological Survey. It has achieved shale gas breakthrough in the Wuling complex structural area outside the southern basin of China. BAOBJECTIVES To quantitatively characterize micro-and nano-pore structure and development characteristics of organic matter, by researching organic matter pore on Longmaxi shale of AnYe-1 well. METHODS Field Emission-Scanning Electron Microscope was used to study the reservoir type of the organic-rich shale of the Longmaxi Formation at the periphery of the basin in the Upper Yangtze region, and the PerGeos digital rock treatment system was introduced into the organic pores quantitative analysis. RESULTS The organic pore is the most important reservoir space of the organic-rich shale of the Longmaxi Formation in Anye-1 well. It is characterized by organic matter interstitially forming in the authigenic siliceous organic matter with uniform sponge-like pore structure, or organic matter that interacts with clay minerals with a bubble-like pore structure. Pores in two different types of organic matter are extremely developed. The PerGeos digital rock system reveals that the pore sizes of the two organic pores show a bimodal distribution, in which the pore size of the organic pores with the sponge-like structure is 5 to 10 nm, and the pore size of the organic pores with the bubble-like structure is 51 to 100 nm. The organic pores are mainly in the mesopore to macropore category. CONCLUSIONS The abundant development of organic matter pores in the Longmaxi Formation in AnYe-1 well indicates that the Longmaxi Formation shale in the periphery of the basin has experienced a strong hydrocarbon generation process and has a good storage capacity, showing a potential for development in the future.

The packaging carton papers of products need to be checked by quality control machine after printing. Thus,a stack of carton papers shall be taken out one by one and placed onto conveyor belt. A paper picking mechanism composed of two cams and five links（including vacuum suction cups） is designed. By alternate use of inversion-graphic method and fitting of analytical formula,the profile of two cams is obtained.With a higher revolution speed,the proposed paper-picking mechanism can steadily pick 1200 carton papers every minute. Driven by the cam-linkage mechanism,its paper-picking suction cup can move in complex trajectories. Instead of interfering with paper bin,the suction cup is completely fitted to paper bin during paper picking and pauses at the right time to provide negative pressure in harmony with gas path. In this way,a smooth and reliable paper picking process is guaranteed.

Objective A titanium personalized orthodontic bracket is designed and manufactured using the technol⁃ ogy of computed tomography (CT), computer aided design (CAD), finite element analysis (FEA), and selective laser melt⁃ ing (SLM) to well match the patient tooth so as to realize mold ⁃free manufacturing. Methods A model of a titanium personalized orthodontic bracket which is built by CT scanning machine and Pro/E software, is imported into Ansys soft⁃ ware to carry out finite element simulation analysis with nonlinear contact method. Then, the titanium personalized orth⁃ odontic bracket is proposed after the model data above is imported to SLM molding equipment via titanium powder melt⁃ ed with layer by layer using a high⁃speed scanning galvanometer. Results The maximum equivalent stress of the titani⁃ um personalized orthodontic bracket is distributed uniformly and reasonably, the titanium personalized orthodontic bracket formed by SLM molding equipment can provide high accuracy and there is a high similarity between the bottom of the orthodontic bracket and the tooth surface shape. Conclusion The combination of CT, CAD, FEA, SLM technolo⁃ gy can fulfill model⁃free manufacturing of the personalized orthodontic bracket and thus shorten the manufacturing cycle.

Aiming at the high speed requirement of industrial flat sewing machine,The kinematics and dynamics models of the thread take-up and needle bar mechanisms are established by using the closed-loop vector method and the simultaneous constraint method,and its kinematics and dynamics equations are deduced.Applying the Simulink module built in the Matlab,the simulink model of the mechanism is built and executed.By analyzing the inertia force and the force in kinematic pair on the mechanism,the conclusion that there is a periodic force which liked an impact force acting on each kinematic pair is obtained.And the periodic forces would cause the rack vibration as well as the abrasion of the kinematic pairs.The analysis for the thread take-up and needle bar mechanism based on the dynamic static analysis method lays a foundation for the further improvement of sewing machine.

In traditional sub-carrier allocation process,user with the highest priority can choose best sub-carrier,which will result in low utilization of sub-carriers.Current improved algorithms can im-prove system capacity and reduce algorithm complexity by sacrificing certain fairness,but they may not achieve fairness requirement among users.In order to solve this problem,a new adaptive resource allo-cation algorithm based on fairness threshold was proposed,in which the priority of the sub-carrier allo-cation was determined by fairness threshold to achieve a rough tradeoff between capacity and fairness.Then power allocation base on particle swarm optimization（PSO） was introduced to realize the required fairness.Experimental results show that the proposed adaptive resource allocation algorithm can satisfy the fairness requirement threshold and improve system capacity.

According to distribution condition of joint fissures of top coal in front of fully mechanized coal face of one coal mine, a numerical calculation model of fully mechanized coal face was built, UDEC software was used to make numerical simulation for fully mechanized coal face with different mining heights under condition of same geology, and deformation features of coal and rock in front of fully mechanized coal face and force condition of top coal were analyzed. The research result showed that reasonable mining height is important factor to ensure stability of roof.

A new pulse design algorithm was proposed to generate UWB pulse based on the relation among the peak frequency of Rayleigh monopulse, the pulse shape parameter α and the order of differentiation n. Not like other algorithms that only work out one pulse, the proposed algorithm can lead to the design of a myriad of pulses that are compliant, namely, it can figure out all α which satisfy the regulation and give out the range of α.

The paper introduced three kinds of different methods of caving methods,namely single-interval caving,single-order caving and multi-interval caving.It used discrete element PFC3D software to simulate the three kinds of caving methods, obtained the simulation results,and analyzed advantages and disadvantages of the three kinds of different methods based on the simulation results.It also proposed some suggestions for improvement of caving methods.

The experiment aimed to analyze the differences in the quality of silage feed from annual pasture grasses in the area around Qinghai Lake, to define the nutritional range of different silage feeds, and to select silage feeds suitable for promotion in the area around Qinghai Lake. In this study, four annual forage treatments in the area around Qinghai Lake were used to harvest silage at the heading stage of oats, each treatment was repeated with five replicates, and the silage was sealed in bags for 60 days, and the pH value, nutritional quality and sensory quality of the silage were measured after opening, and the nutritional value and relative feeding value of each treatment were comprehensively evaluated by the grey correlation method. The results showed that the sensory evaluation grades of Avena sativa' Qingyin No. 1' (Q1) and Huayouza 62 + Avena sativa' Qingyin No. 1' (H62 + Q1) treatments were high-quality. The pH value of the seven treatments was between 3.8~4.1. The water content and crude ash content (Ash) of Q1 were significantly lower than those of other treatments (P<0.05), the concentrations of dry matter (DM) and neutral detergent fiber (NDF) were significantly higher than those of other treatments (P<0.05), and the relative feeding value (RFV) of the seven treatments was between 108~141. The relative feeding value (RFV) and dry matter intake (DMI) of Vicia faba L. variety 'Qinghai 13' + Vicia sativa (Q13 + J) silage were significantly higher than those of other treatments (P<0.05).The results showed that the tested annual forage grass could be successfully silaged in the area around Qinghai Lake, and there was no inferior grade in the sensory evaluation of seven treatments, and Q13 + J silage had the highest relative feeding value, the best palatability, and was easier to be eaten by livestock. According to the comprehensive analysis of the grey correlation method, the Q1 silage is more suitable for application and promotion in the area around Qinghai Lake. [ABSTRACT FROM AUTHOR]

The study aims to select high-yielding and high-quality triticale cultivars that are well-suited for cultivation in northwest Henan region through an evaluation of six triticale varieties (Triticosecale wittmack) in terms of forage production, quality, seed yield, and composition factors. The findings indicated noteworthy disparities among the tested varieties concerning forage production, nutritional quality, and seed yield. Notably, the 'GN2' cultivar exhibited the highest hay yield (21.49 t/hm²), number of branches (9 330 500 /hm²), and crude protein content (11.86%). Furthermore, 'ZS1257' demonstrated the highest seed yield (6.55 t/hm²) and spiked grain count (56.00 grains). The yield of triticale varieties showed an increasing and then decreasing trend with the increase in the number of tillers, it gradually decreased with the increase in the weight of individual leaves and stems. The contribution of related factors to the grain yield was in the following order: number of grains per ear > thousand-grain weight > number of tillers. The study indicates that through comprehensive evaluation, 'GN2' ranks first and can be promoted as a forage-type triticale for planting in the northwest Henan region. [ABSTRACT FROM AUTHOR]

The northern Daxinganling Mountains is an important part of Daxinganling metallogenic belt, where copper is the main mineral, dominated by porphyry type, large in scale, with great economic value and scientific research significance. Based on the systematic summary of regional geological background and mineralization process of copper deposits in different ages in northern Daxinganling Mountains, the paper summarizes the new exploration results in the area in recent years, and points out that the western margin of Ergun block, southeastern margin of Xing'an block, and suture zone of the two blocks are important for copper deposit prospecting. Attention should be also paid nearby the existing deposits and blind orebodies in the deep for the exploration of copper deposits in northern Daxinganling Mountains. [ABSTRACT FROM AUTHOR]

Objective: To investigate the active components, protein targets, and mechanisms underlying the anti-obesity effects of Hippophae fructus using network pharmacology and molecular docking techniques, and to validate its in vitro anti-obesity efficacy. Methods: The TCMSP platform was utilized to retrieve the active components and targets of Hippophae fructus, and disease targets were collected. Venny 2.0.2 was used to identify the intersection of targets between Hippophae fructus and obesity-related targets. The STRING database was used to establish a drug-target-disease protein interaction (PPI) network. The intersecting targets were analyzed using the David database to perform GO enrichment analysis and KEGG pathway analysis. Cytoscape 3.9.1 was used to construct a network diagram of the components of Hippophae fructus, anti-obesity targets, and related signaling pathways. Autodock Dock 1.5.7 and Pymol 2.2.0 were used to carry out molecular docking between the core targets of Hippophae fructus and its components, followed by visualization. The in vitro anti-obesity effect of Hippophae fructus extract was evaluated through cell experiments using 3T3-L1 cells. Results: A total of 33 active components, 2820 disease targets, and 151 intersection targets of Hippophae fructus were identified. The main active components included flavonoids, vitamins, and sterols, while key targets involved AKT1, TNF, IL6, TP53, VEGFA, CASP3, and others. KEGG pathway enrichment analysis revealed 131 signaling pathways, including those related to malignant tumors, lipid and atherosclerosis, and AGE-RAGE signaling. Molecular docking results demonstrated favorable binding interactions between the core targets and the corresponding active components of Hippophae fructus. The in vitro experiments indicated that Hippophae fructus extract exhibited inhibitory effects on the proliferation of 3T3-L1 pre-adipocytes. Conclusion: This study reveals that Hippophae fructus exerts antiobesity effects through multiple components, targets, and pathways, providing valuable insights for its clinical research and product development. [ABSTRACT FROM AUTHOR]

To improve peanut yield under drip irrigation in Xinjiang, effect of potassium fertilizer application was investigated. Huayu 9610 (T1, a common cultivar in Xinjiang) and Heihua 5 (T2, a high yield cultivar) were used as materials at the Agricultural Meteorological Experiment Station in Wulanwusu, Xinjiang. Four potassium (K2O) fertilizer gradients were set as K0 (0 kg/hm²), K1 (150 kg/hm²), K2 (225 kg/hm²) and K3 (300 kg/hm²), and thus the potassium rates were at 15%, 40%, 30% and 15% at the seedling, pegging, podding and full fruit ripening stages respectively. Results showed that the main stem height and lateral branch length of Huayu 9610 and Heihua 5 changed parabolically with the increase of potassium application. The dry matter accumulation were the highest at K2 level, which were 84.37 g per plant and 89.37 g per plant, respectively. Compared with no potassium fertilizer, the main stem height and lateral branch length of K2 treatment increased by 17.91% and 16.56%, 7.4% and 12.31%, respectively. The number of nodules was the highest at podding stage, which was 42.0 per plant and 45.3 per plant respectively. The leaf area index increased with the increase of potassium fertilizer application, and reached the maximum at 90 days after emergence. The photosynthetic potential also changed in a parabolic shape with the increase of potassium fertilizer application rate, and reached the maximum value of 4.38 m2·d and 4.51 m2· d respectively after 75-90 days of K2 treatment. The fertilizer contribution rate and agronomic utilization rate of K2 treatment were the largest, which were 26.06% and 1.83 kg/kg (for Huayu 9610), 25.18% and 1.67 kg/kg (for Heihua 5), respectively, and the yields were 9628.38 kg/hm² and 10 368.35 kg/hm², respectively. The results showed that potassium application amount of 225 kg/hm² at K2 level could be used as reference for drip irrigation peanut in Xinjiang, China. [ABSTRACT FROM AUTHOR]

The reservoir sediment is formed by the combination and precipitation of clay, sand, organic nutrients and inorganic minerals in the reservoir. The reservoir sediment usually exists in the form of irregular and heterogeneous clay glue, which is in a fluid plastic state with good plasticity and relatively loose between particles. The accumulation of sediment in the reservoir will weaken the water storage and flood control capacity of the reservoir, and then reduce the capacity of the reservoir, shorten the life of the reservoir, and affect the shipping traffic. In addition, the long-term accumulation of reservoir sediment may cause pollution to the surrounding environment and reduce the water environment safety index, thus posing a potential threat to human survival. Therefore, it is urgent to make resource utilization of reservoir sediment. In order to improve the added value utilization rate of reservoir sediment in the field of building materials, this paper uses the reservoir sediment as auxiliary cementing material to prepare pervious concrete. Through the orthogonal test, the mix ratio design optimization of pervious concrete with reservoir sediment is studied, and the effects of slag powder, reservoir sediment and reinforcement agents on the performance indexes of pervious concrete with reservoir sediment, such as dry density, total porosity, effective porosity, permeability coefficient, ultrasonic pulse velocity and 28 d compressive strength are analyzed. The relationship between ultrasonic pulse velocity and porosity, permeability coefficient and 28 d compressive strength is studied, and the evolution law of the quality of the specimen and ultrasonic pulse velocity with the number of freeze-thaw cycles is explored. The results show that the dry density, compressive strength and ultrasonic pulse velocity of pervious concrete decrease continuously with the addition of reservoir sediment, and the porosity and permeability coefficient increase continuously. When slag powder is added, the dry density, compressive strength and ultrasonic pulse velocity of the specimen first increase and then decrease, and the porosity and permeability coefficient first decrease and then increase. The reinforcement agent has no obvious effect on the performance index of the specimen. The curve fitting of ultrasonic pulse velocity with porosity, permeability coefficient and 28 d compressive strength is well correlated. With the increase in the number of freeze-thaw cycles, the quality loss rate of the specimen increases gradually, the ultrasonic wave speed decreases gradually, and the slag powder and reinforcing agent can improve the freeze--thaw durability of the specimen. The research findings will promote the development and application of reservoir sediment in the preparation of building materials, and is expected to serve as a reference for the further application of reservoir sediment permeable concrete. [ABSTRACT FROM AUTHOR]

Plant height (PH) is associated with fusarium head blight (FHB) resistance in wheat. In this study, a recombinant inbred lines (RIL) population derived from the cross of Yangmai 4/Yanzhan 1 (YM4/YZ1) was used to mine the quantitative trait loci (QTL) of PH traits using 55K SNP (single-nucleotide polymorphism) chip data, combined with the PH data of RIL population and their parents in six environments for three continuous years. Soil surface inoculation method and single spikelet inoculation were used to identify the FHB resistance to infection (Type I) and spread (Type II), respectively. Seven QTLs related to PH were detected on chromosomes 2D, 4B, 4D, 5A, and 7D, and only QPh.yas-2D.2 may be a new QTL of PH after comparing with previous studies. The dwarfing effects of QPh.yas-2D.1, QPh.yas-2D.2, and QPh.yas-5A were derived from YM4, and the dwarfing effects of the other four QTLs were derived from YZ1. Both QPh.yas-4D and QPh.yas-5A could be detected in six environments, and phenotypic variation explained (PVE) rates ranged from 19.48%--44.11% and 10.48%-13.71%, respectively. The increasing alleles at the Rht-D1 and QPh.yas-7D.2 (YM4 allele) significantly reduced the average percentage of infected spikelets (PIS) by 34.97% and 19.09%, respectively. The dwarfing alleles at QPh.yas-2D.2 and QPh.yas-5A (YM4 allele) significantly reduced the average percentage of diseased spikelets (PDS) by 24.73% and 14.56%, respectively. The dwarfing allele of QPh.yas-5A was derived from Funo. Furthermore, we preliminary analyzed the genes within the physical interval of QPh.yas-5A using the reference genome information of wheat version 2.1. A total of 146 high-confidence annotated genes were detected in the target interval, which were mainly involved in the synthesis of cytochrome P450, dehydration response element-binding protein, ethylene response transcription factor, transcription factor MYC2, and cell wall receptor-associated kinases. The SNP marker closely linked to QPh.yas-5A was further converted into kompetitive allele-specific PCR marker KASP-5A, and its effect on plant height and FHB resistance was then verified in 126 wheat cultivars (lines). The results of this study could provide a solid foundation for future fine mapping QPh.yas-5A. [ABSTRACT FROM AUTHOR]

In confined settings such as parking lots, where the available space for vehicle maneuvering is restricted, and the proximity between the vehicle and obstacles is minimal, the vehicle is susceptible to collisions during its course of travel. Therefore, precise and stable vehicle control is a top priority for intelligently assisted driving technology. To mitigate the frequent incidence of such accidents, it is imperative to conduct further optimization of the vehicle tracking control algorithm. This optimization should be centered on augmenting the accuracy of vehicle control and enhancing the efficiency of the solver solution. With this goal in mind, an enhanced nonlinear model predictive control approach for vehicle trajectory tracking is proposed. This approach is rooted in the principles of nonlinear model predictive control ( NMPC ), which integrates the concept of variable look-ahead distance to generate multiple preview points. Subsequently, it establishes the kinematic model for both forward and reverse vehicle motion. Then, the kinematic model for vehicle forward and reverse motion is discretized through the application of a customized second-order Runge-Kutta method, which converts the differential equations of the kinematic model into discrete state-space equations, This discretization process is instrumental in enhancing the accuracy and efficiency of the control algorithm, particularly in confined spaces like small parking lots. Finally, to tackle the issue of computational load induced by nonlinear optimization, an innovative dynamic moving block matrix strategy is introduced to limit the extent of control. In a single controller solution cycle, the initially fixed block matrix undergoes a transformation, evolving into four dynamic moving block matrices. This transformation enables the precise computation of the first element while employing a fuzzy computation approach for the other elements. This restructuring endeavor serves to reduce the number of independent inputs required for solving the diiferential equations, decrease the degrees of freedom within the optimal control problem, and consequently alleviate the computational complexity associated with the solver. Simulation experiments are conducted on the Carsim/Simulink simulation platform, considering multiple target points. Using the hybrid algorithm for trajectory planning and employing the provided paths as navigation references, a number of experiments were conducted to validate the tracking performance of the proposed nonlinear control method. The outcomes of these simulations clearly demonstrate the efficacy of the proposed control method. It successfully reduces lateral errors by 50. 4% and 28. 21% compared to the feed-forward PID method and the traditional NMPC method, respectively. This substantial improvement underscores the effectiveness of the novel control approach. Furthermore, the reduction in heading error was 19.58% and 12.53%, respectively. When addressing trapezoidal and curved traj'ectories, the proposed method demonstrates substantial improvements in time efficiency. More precisely, it reduces the solution time by 28. 73% and 9. 89%, in comparison to the traditional NMPC method. Consequently, the introduced method has demonstrated a substantial enhancement in tracking precision and numerical solution efficiency. This enhancement underscores the practical value and effectiveness of the proposed approach in addressing complex and demanding scenarios, such as those found in confined parking environments. This innovative technique offers a promising framework for advancing vehicle control in constrained environments such as small parking lots. [ABSTRACT FROM AUTHOR]

Clubroot disease has spread explosively in recent years, posing a serious threat to cruciferous crop production. Take rapeseed for example, according to the statistics, until year 2022 the incidence of the clubroot has exceeded 1.33 million hectares in China. Breeding for resistant cultivars is considered as the most efficient and economical way to prevent clubroot disease spreading. However, the current CR cultivars mostly used CR loci of PbBa8.1 or CRb. Due to the complexity and diversity of Plasmodiophora brassicae from different locations, resources for resistant germplasm need to be explored. In this study, 14 clubroot-resistant Chinese cabbages were characterized using different clubroot pathogens and molecular markers for known CR loci. We found that among them, five materials, DG117, ZS105, SG01, SR06 and JQ07 did not contain CRb locus, and their disease resistance were stronger than Huashuang5R/Huayouza5R. At last, KL02 containing the CRb locus showed stronger resistance to PbXM (strain from Xinmin) than 409R, therefore it may contain other novel loci leading to better resistance. These six Chinese cabbage resources can be considerd as new resistance resources and could be utilized in future breeding work for CR Brassica napus. [ABSTRACT FROM AUTHOR]

The Tesla valve has a special structural form that can guide the flow entering from the reverse port into two sets of straight/curved channels, and dissipate energy through friction and collision at the end of the guide column, greatly weakening the flow velocity in the pool. This unique flow characteristic is very suitable for designing fishways. However, direct applying the original structure of Tesla valves as a fishway has been proven to have significant limitations. The original structure of the Tesla valve fishway is optimized in this paper. By adjusting the aspect ratio of the straight/curved channel in the fishway pool, hollowing out the guide column, and increasing the length of the opening end, a new Tesla valve fishway with relatively independent energy dissipation channels and fish upstream channels has been obtained. The hydraulic characteristics parameters of the optimized Tesla valve fishway are compared with the original structure using numerical simulation, with a focus on analyzing the flow velocity variation, flow field, and turbulent energy distribution of the new Tesla valve fishway. The results show that the new Tesla valve fishway has significant advantages compared to the original structure. While maintaining the same energy dissipation efficiency, it effectively improves the flow pattern in the pool, and the overall flow velocity and turbulent kinetic energy are smaller than the original structure. The new structure significantly increases the proportion of rest areas. When the pool bottom slope gradient from 1% to 3%, the proportion of rest areas in the original Tesla valve fishway is 8.5% to 1.2%, while the proportion of rest areas in the new Tesla valve fishway is 44.7% to 25.8%, increasing the possibility of successful fish upstream migration. The flow velocity and turbulent kinetic energy of the new structure increase with the increase of the bottom slope gradient, but the flow velocity remains low in the fish upstream channels, while the high flow velocity mainly occurs in the energy dissipation passage. The maximum flow rate increase rate in the energy dissipation channel of the first two stages of the pool is relatively high, while after the third stage of the pool, the increase rate tends to slow down. The overall turbulent kinetic energy in the fish upstream channels is relatively low. When the bottom slope gradient is less than 2.5%, the upstream conditions and economy of the fishway are better. [ABSTRACT FROM AUTHOR]

This paper summarized the pain management during radiotherapy in a patient with liver cancer. Nurses had conducted comprehensive assessments on pain and health needs of the patient, and carried out pain control strategy through drug intervention, psychology support, diet guidance, lifestyle guidance and exercise, aiming to relieving the pain and improve patient’s quality of life. (本文总结1例肝癌患者放治疗期间的疼痛管理经验。护理人员积极评估患者疼痛程度和性质, 了解患者需求, 针对性给予药物镇痛、心理支持、饮食干预、健康宣教、运动指导等护理措施, 有效减轻患者疼痛, 提高生活质量。)

This paper reviewed current research status of pain catastrophizing in patients with lung cancer after surgery, and summarized the concept, theoretical basis, assessment tools, epidemiological characteristics, influencing factors and management strategies of pain catastrophizing, in order to provide theoretical support for medical personnel to develop targeted and effective pain management strategies. (综述肺癌术后患者疼痛灾难化的研究现状, 归纳疼痛灾难化的概念、理论基础、评估工具、流行病学特征、影响因素及管理策略, 旨在为医务人员制定针对性、有效性的疼痛管理策略提供理论支持。)

In order to promote the development of hair transplantation, particularly the establishment of standards, the Hair Transplantation Expert Group of Plastic and Aesthetic National Medical Quality Control Center invited experts in the field of hair transplantation across China and formed a draft of the Expert Consensus on Standard Terminology for Hair Transplantation based on the collation of relevant literature and monographs. By combining Delphi methodology and consensus meetings, the expert group conducted several rounds of consultations on issues such as follicular unit anatomy, harvesting, dissection, and implantation, ultimately presenting 54 terminologies. This consensus considers the original Chinese and English meanings as well as the professional characteristics of terms used in hair transplantation, highlights the unique features and advantages of hair transplantation, and preserves its essence while promoting innovation, with the hope of providing valuable reference for clinical researchers engaged in hair transplantation both domestically and internationally, and better facilitating the standardization and advancement of the field.

BackgroundsInsomnia is frequent in schizophrenia and is found to be negatively affected by stressful life events， psychotic symptoms and depressive disorder， while the relationship among the four remains understudied in community-dwelling patients with schizophrenia.ObjectiveTo analyze the effect of stressful life events on insomnia in community-dwelling patients with schizophrenia， and to explore the mediation effect of psychotic symptoms and depression， so as to provide references for the intervention of insomnia in community-dwelling patients with schizophrenia.MethodsFrom April to June 2023， a sample of 1 105 patients with schizophrenia attending 48 community health centers in Chengdu， Sichuan province and fulfilling the International Classification of Diseases， tenth edition （ICD-10） diagnostic criteria were included. All subjects were assessed using Stressful Life Event Scale （SLEs）， Athens Insomnia Scale （AIS）， Psychosis Screening Questionnaire （PSQ）， and Patient Health Questionnaire Depression Scale （PHQ-9）. Spearman correlation analysis was used to determine the correlation among the scales. Then the mediation model was constructed using Smart PLS 4.0， and tested with partial least squares algorithm and Bootstrap techniques.Results332 patients （30.05%） with community schizophrenia were found to have insomnia. AIS scores in patients with schizophrenia were positively correlated with the scores on SLEs， PSQ and PHQ-9 （r=0.165， 0.322， 0.554， P

【Objective】 Spring wheat is an important cereal crop in Northern Xinjiang, where limited precipitation during the growing season makes irrigation essential for its successful production. This paper investigates the effect of irrigation amount on its growth traits and final yield, in attempts to identify an optimal irrigation schedule for spring wheat in this region. 【Method】 The field plot experiments were conducted using the high-yielding varieties ‘Xinchun 37’ and ‘Xinchun 44’. Each variety was subjected to four irrigation treatments: 4 500 m3/hm2 (W1, resulting in severe drought), 5 250 m3/hm2 (W2, resulting in moderate drought), 6 000 m3/hm2 (W3, normal irrigation), and 6 750 m3/hm2(W4, excessive irrigation). For each irrigation treatment, we measured the growth traits, water use efficiency, and grain yield of the two crops. 【Result】 Soil water content in the 0-60 cm layer increased with the irrigation amount, with water in the 0-20 cm soil layer showing the most significant fluctuation. With the increase in irrigation amount, plant height and dry matter accumulation of both varieties increased initially, followed by a decline. It was also found that the grain-filling period of Xinchun 37 was longer than that of Xinchun 44. Compared to W4, W3 increased the water use efficiency of Xinchun 37 and Xinchun 44 by 30.00% and 15.45%, respectively, the irrigation water use efficiency by 33.91% and 19.85%, respectively. Compared to all other treatments, W3 increased the grain yield of Xinchun 37 by 14.45%-38.24%, while compared to W1 and W2, it increased the grain yield of Xinchun 44 by 25.76% and 14.45%, respectively. 【Conclusion】 Regression analysis shows that the optimal irrigation amount for Xinchun 37 and Xinchun 44 was 5 875.83 m3/hm2 and 5 967.67 m3/hm2, respectively, in the studied region.

Deep geothermal resources in China are widely distributed, with large reserves, and have broad prospects for development and utilization. In order to investigate the seepage characteristics and evolution laws of deep high-temperature reservoirs under the condition of intermittent water injection geothermal exploitation. Using the combines method of laboratory testing and microscopic analysis, a seepage test was carried out on granite after alternating thermal and cold cycles at different temperatures, and the variation of permeability with temperature under different confining pressure were analyzed. Combining microscopic characteristics and CT scaning reconstruction results, the evolution of the microscopic pore and crack structure with temperature and cycle times was studied. The results indicated that: (1)The permeability of granite is related to temperature and cycle numbers. Under the two cooling methods, the permeability of granite gradually increases with the increase of temperature, and the permeability increases sharply when the temperature exceeds 500℃. In addition, the permeability increase under water-cooled conditions is significantly greater than that under natural cooling conditions, and the parameter changes after 10 water-cooled cycles are more significant. (2)The stress state has a significant influence on the permeability. Under the confining pressure, the internal pore and fracture structure of the specimen is closed. With the increase of confining pressure, the permeability of the granite decreases after the alternating hot and cold cycles at different temperatures, and gradually increases with the increase of osmotic pressure. (3)Under the action of high temperature cooling cycle, micro-pore cracks in granite gradually develop, temperature gradient stress causes non-uniform deformation among mineral particles, and degradation damage such as intergranular cracks, transgranular cracks and particle spalling occurs under the combined action of physical and chemical reactions such as dehydration and phase transformation. With the increase of cycle times, the number, size and connectivity of cracks further increase. The research results can provide theoretical support and technical reference for geothermal development and reservoir construction in deep dry hot rock.