Search

For obtaining a thick ceramic coating with good film-forming and wear resistance, a new type of composite electrolyte was composed of sodium phosphate and sodium hexametaphosphate as the basic electrolytes, while sodium tungstate and sodium tetraborate were added as additives. In this composite electrolyte system, micro-arc oxidation treatment was performed on 1060 aluminum alloy. Using the coating thickness and surface porosity as optimization indicators, the electrolyte formula was optimized using the L9(34) orthogonal test. Meanwhile, the microstructure, surface porosity, phase composition, thickness, microhardness and wear resistance of ceramic coatings prepared under this electrolyte formula were studied systematically. Results showed that the ceramic coating prepared with a formula of Na3PO4 concentration of 32.0 g/L, Na2B4O7 concentration of 16.0 g/L, Na2WO4 concentration of 4.5 g/L and(NaPO3)6 concentration of 30.0 g/L had the structure with uniform micropores and dense film layer, the thickness of 22.8 μm, the porosity of 3.86%, and the microhardness of 475 HV. Furthermore, the wear resistance of the coating was significantly improved compared to the substrate, and the ceramic coating were mainly composed of γ-Al2O3 and a small amount of α-Al2O3 composition.

Due to continuous heavy rainfall, landslides were triggered in Biyi Village, Ganluo County, Sichuan Province, resulting in significant property losses. This paper explores the causes of the landslide in Biyi Village by analyzing the local engineering geological conditions, and conducts a true three-dimensional numerical simulations of the entire landslide process using the smoothed particle hydrodynamics (SPH) method. Displacement and velocity monitoring were performed at key positions of the landslide. The results indicate that: (1) unfavorable geological conditions and long-duration, high-intensity continuous rainfall were the main triggering factors of the landslide. (2) The SPH method obtained displacement, velocity, and other motion-related parameters that closely aligned with the actual survey results, demonstrating its good reliability and accuracy. (3) The landslide was caused by the sliding of the rear edge of the landslide, pushing the middle part of the landslide, resulting in overall downward movement and blockage at the front edge, ultimately leading to the formation of a bulging zone. The final landslide failure mode was characterized as a translational slide. (4) The Biyi Village landslide is still in the creep stage. Utilizing the capabilities of the SPH method in simulating large deformations opens up new avenues for research in understanding the mechanisms and engineering strategies for the prevention of similar disasters.

This paper expounded the characteristics of concentrated fruit juice, and the advantages, disadvantages and optimization of common concentrated technologies, summarized the research status of fermented fruit wine with concentrated fruit juice as raw material, and looked forward to the research direction of fermented fruit wine with concentrated fruit juice as raw material.

The evaluation indicators of fruit wine including sensory evaluation, physicochemical indicator, safety indicator, flavor composition and efficacy are summarized, and the impact of each index on fruit wine quality and research progress are also introduced. Moreover, the quality improvement and the relative quality evaluation system of the fruit wine is prospected.

Objective To investigate the enhancing effect of platycodon grandiflorum saponin D on the sensitivity of human rectal cancer drug-resistant cell line SW1463 to oxaliplatin (Oxa). Methods Human rectal cancer cell line SW1463 was collected to establish a stable oxaliplatin-resistant cell strain SW1463/Oxa. The constructed cell strain SW1463/Oxa was randomly divided into platycodon grandiflorum saponin D group, Oxa group, platycodon saponin D+Oxa group and control group. The cell proliferation curve was detected by MTT. Deoxyribonucleic acid methyltransferase 3a (DNMT3a), phosphorylated histone γ-H2AX, DNA double strand repair protein RAD51 and signal transducer and activator of transcription 3(STAT3) messenger RNA (mRNA) expression were detected by RT-qPCR. DNMT3a, γ-H2AX, RAD51, STAT3 protein expression and phosphorylated STAT3(p-STAT3) level were detected by Western blot. Results Human rectal cancer drug resistant cell strain SW1463/Oxa was successfully constructed. Compared with the control group and Oxa group, the cell proliferation, DNMT3a, RAD51, STAT3 mRNA and protein expression and p-STAT3 level of platycodon saponin D group and platycodon saponin D+Oxa group decreased(P＜0.05), and the expression of γ-H2AX mRNA and protein increased(P＜0.05). Conclusions Platycodon grandiflorum saponin D may enhance the chemo-sensitivity of human rectal cancer drug-resistant cell strain SW1463/Oxa to Oxa, and the potential mechanism is inhibition of expression of DNMT3a, RAD51, STAT3 and promotion of expression of γ-H2AX.

In order to solve the problems of difficulty, low efficiency, and insufficient data to support large-scale training in existing power system detection methods, a few-shot detection method based on siamese network was proposed. Firstly, under the framework of Faster RCNN(region convolutional neural network) object detection algorithm, a siamese network model supporting imageand querying image sharing was built. Then, the improved RPN (region proposal network) module was used to generate proposals of higher quality. Finallly, the RoI(region of interest) supporting and querying images was correlated and matched on the detection head. The results show that the proposed algorithm, applied to the self-constructed EPD(electric power detection) dataset, can detect foreign matters in bird nest and insulator in the power background, and the detection index reaches 1892% mAP, in the case of only 10 supporting images. Compared with other algorithms, the siamese network model with small sample size has better performance under extremely few shot situations, and has the advantage of being more lightweight, which provides some reference for the new research direction of electric power detection.

The k-step reachability query processing on label-constrained graph is used to answer whether there is a path with a length not greater than k between two points and the labels on this path are in the specified label set.The k-step reachability query processing on label-constrained graph is widely used in reality,but there is no relevant algorithm to answer it.Therefore,the LK2H algorithm is proposed firstly.LK2H algorithm mainly consists of two steps.The first step is to build a pair of 2-Hop in-dexes containing k and label information for all vertices on the graph,and the second step is querying based on the built index.In order to return information as much as possible to the user,LK2H optimizes the results of a type of unreachable query:when the user cannot specify all the label types,and cannot give full label constraints resulting in unreachable query results,the complete label set will return to the user.Secondly,an optimization algorithm,LK2H+,is proposed.LK2H+ algorithm further reduces the index size and time of construction by building a 2-Hop index for part of vertices,and queries based on the built index.Queries require a discussion of whether query vertices are indexed or not.Finally,the test is conducted based on 15 real-world datasets.Experiment results show that both LK2H and LK2H+ algorithms can solve k-step reachability query processing on label constraint graphs efficiently and quickly.

Semantic segmentation of urban scenes aims to identify and segment persons,obstacles,roads,signs and other elements from the image,and provide information of free space on the road for vehicles.It is one of the key technologies of automatic dri-ving.High performance semantic segmentation systems rely heavily on a large number of real annotation data required for trai-ning.However,labeling each pixel in the image is costly and often difficult to achieve.One way is to collect photo-realistic synthe-tic data from video games,where pixel-level annotation can be automatically generated at a low cost,to train the machine learning model to segment the images in the real world,which corresponds to domain adaptation.Different from the current mainstream semantic segmentation domain adaptation methods based on Vapnik-Chervonenkis dimension theory or Rademacher complexity theory,our method is inspired by the target domain Gibbs risk upper bound compatible with pseudo labels based on PAC-Bayes theory,and considers the average situation of the hypothetical space rather than the worst situation,so as to avoid excessively constraining the domain discrepancy in the latent space which leads to the problem that the upper bound of target domain genera-lization error cannot be estimated and optimized effectively.Under the guidance of the above ideas,this paper proposes a varia-tional inference method for semantic segmentation adaptation(VISA).The dropout variational family is used for variational infe-rence.While solving the ideal posterior distribution in the hypothesis space,an approximate Bayes classifier can be quickly obtained,and the estimation of the upper bound of risk is more accurate by minimizing the entropy of the target domain and filtering pixels.Experiments show that the mean intersection over the union(mIoU) of VISA is 0.5% ~ 6.6% higher than that of baseline methods,and has high accuracy in pedestrian,vehicle and other urban scene elements.

Obtaining stereoscopic information is one of the basic abilities of human beings to perceive the world.Through stereo vision,we can judge the shape,size,distance,relative position of objects,as well as the direction and speed of changes in object motion information.Among them,the perception information of moving objects plays an important role in stereo vision perception.The acquisition of motion visual information is not only the key ability of biological vision systems to survive in a dynamic world,but also an important means for artificial vision systems to efficiently process stereoscopic video.Therefore,in order to design a 3D depth motion perception model that conforms to the visual characteristics of human eyes,it is necessary to explicitly excavate the salient features of human perception of stereoscopic motion,so as to design experiments to explore.In this paper,motion stereo videos are designed as visual stimuli based on monocular and binocular cues,and subjective experiments are designed using the control variable method.The experiment explores two parts:the influence of the relative distance between the target and the reference sphere on the subjects’ perception ability,and the relationship between the actual movement direction of the target and the subjects’ perception direction.Experimental data is analyzed by using two behavioral measures:the percentage of successfully intercepted targets and the perceived bias.The conclusion shows that,firstly,the smaller the relative distance between the target and the reference,the higher the interception success rate.The target velocity and the reference’s motion radius affect the relative distance of the target and reference spheres.This indicates that the relative positional relationship between the target and the reference plays an important role in the human eye’s perception of moving objects.Motion perception has a certain relativity,and motion is easier to perceive at the position with reference point and the position close to the reference point.Second,we find that perceptions elicited by deep motion are more pronounced than those induced by lateral motion.The correct intercept rate of perceived depth direction is 42.67%～47.01% higher than that of lateral motion.This shows that the visual stimulation brought by deep motion is more obvious,and the perception ability of objects moving in different directions is asymmetric.However,when there is an interception error in the depth direction,the perceptual deviation is larger,and the deviation is about 0.1583~0.3665.This study explores the salient features of human perception of motion and provides insights into the observer’s process of motion perception in 3D environments.This study explores the significant characteristics of human motion perception,and provides a new subjective contrast standard to judge the perception effect of 3D motion perception model for the subsequent design of 3D motion perception model work,which makes the original stereo perception ability index more refined.

As a structured form of human knowledge,knowledge graphs have played a great supportive role in supporting the semantic intercommunication of massive,multi-source,heterogeneous data,and effectively support tasks such as data analysis,attracting the attention of academia and industry.At present,most knowledge graphs are constructed based on non-real-time static data,without considering the temporal characteristics of entities and relationships.However,data in application scenarios such as social network communication,financial trade,and epidemic spreading network are highly dynamic and exhibit complex temporal properties.How to use time series data to build knowledge graphs and effectively model them is a challenging problem.Recently,numerous studies use temporal information in time series data to enrich the characteristics of knowledge graphs,endowing know-ledge graphs with dynamic features,expanding fact triples into quadruple representation(head entity,relationship,tail entity,time).The knowledge graph which utilizes time-related quadruples to represent knowledge are collectively referred to as temporal knowledge graph.This paper summarizes the research work of temporal knowledge graph representation learning by sorting out and analyzing the corresponding literature.Specifically,it first briefly introduce the background and definition of temporal know-ledge graph.Next,it summarizes the advantages of the temporal knowledge graph representation learning method compared with the traditional knowledge graph representation learning method.Then it elaborates on the recent method of temporal knowledge graph representation learning from the perspective of the method modeling facts,introduces the dataset used by the above method and summarizes the main challenges of this technology.Finally,the future research direction is prospected.

Objective To explore the effect of esculin on the biological behavior of nasopharyngeal carcinoma cells and its possible mechanism. Methods Different concentrations of esculin were used to treat human nasopharyngeal carcinoma cells HNE-3, si-NC, si-circ-ZNF609 were transfected into HNE-3 cells, pcDNA, pcDNA-circ-ZNF609 were respectively transfected into HNE-3 cells and then treated with esculin. CCK-8 experiment was used to detect cell proliferation. Intracellular glucose uptake levels and lactate levels were tested using kits. The activity of pyruvate kinase and hexokinase was tested using an enzyme activity kit. The Transwell chamber test was used to find cell migration and invasion. RT-qPCR method was used to detect the expression of circ-ZNF609. Protein expression of MMP-2 and MMP-9 was calculated by Western blot. Results Esculin could reduce cell survival rate and the protein levels of MMP-2, MMP-9 in a concentration-dependent manner (P＜0.001), could reduce glucose uptake and lactate levels (P＜0.001), and may reduce pyruvate kinase and the activity of hexose kinase (P＜0.001), could also reduce the number of migrating and invading cells (P＜0.001). Esculin could reduce the expression of circ-ZNF609 (P＜0.001), and it was dose-dependent. After transfection with si-circ-ZNF609, the cell survival rate and the protein levels of MMP-2, MMP-9 were decreased (P＜0.001), glucose uptake and lactate levels were decreased(P＜0.001). The activity of pyruvate kinase and hexokinase and the number of migrating and invasive cells were all decreased (P＜0.001). Transfection of pcDNA-circ-ZNF609 may restore the inhibitory effects of esculin on the proliferation, glycolysis, migration and invasion of HNE-3 cells. Conclusions Esculin could inhibit cell proliferation, glycolysis, migration and invasion in HNE-3 cells by regulating the expression of circ-ZNF609.

The screening and identification of functional genes is a key step to deeply understand various biological phenotypes. Forward genetics including traditional genetics, genome-wide association analysis, the comparison of gene expression profiles and bioinformatics, and reverse genetics including cDNA library, RNA interference, CRISPR-Cas9 technology, insertion mutation as well as model organisms have been applied to screening functional genes. Different methods have their own advantages and disadvantages and technology combination to screen and to identify functional genes is a good choice of strategy.

The quantification of hepatitis B virus(HBV) core antibody (anti-HBc) is related to host immunity and can be detected in the serum of patients with current or past infections. The antibody against core antigen of HBV plays an important role in the inflammation pathogenesis of liver,evaluation of epidemiology history and of treatment strategy. Chronic HBV infection is closely related to active transcription and persistence of covalently closed circular DNA(cccDNA) in the liver. The result of quantitative anti-HBc antibody examination shows a good correlation with cccDNA level so it is a potential index for comprehensive evaluation of HBV infectious diseases.

This paper performed a retrospective analysis of 19 patients diagnosed with pathologically-verified WHO Ⅱ-Ⅲ grade glioma with T2/FLAIR mismatch sign. We extracted the overall characteristics of the tumor area and the image parameters of the mismatch regions from the patients' imaging data for quantitative analysis. Afterward, we investigated how T2/FLAIR mismatch sign affected the diagnostic efficacy for isocitrate dehydrogenase (IDH)-mutant and 1p/19q non-codeleted (IDHMUT/1p/19q+) lower-grade gliomas (LGG). This study showed that the overall and partial T2/FLAIR mismatch sign can be used as an imaging marker to predict IDHMUT/1p/19q+ LGG. The overall imaging characteristics of the tumor area combined with the quantitative parameters of the mismatch regions can improve the diagnostic efficacy for IDHMUT/1p/19q+ LGG.

Based on seismic, drilling data and experimental analysis, the characteristics and main controlling factors of shoal dolomite gas reservoir in the third member of Ordovician Yingshan Formation of Gucheng area, Tarim basin were examined. The study shows that the dolomite gas reservoir in Gucheng area is lithologic gas reservoir controlled by shoal and fault jointly, and its formation is mainly attributed to the following factors: (1) The continuously developing paleotectonic structure has been in the direction of gas migration and accumulation; (2) The large area of medium—high energy grain bank deposited in gentle slope environment is the material basis for the formation of dolomite reservoir; (3) Atmospheric water leaching and dolomitization and fluid dissolution in fault zone are the key factors for the formation of high-quality dolomite reservoir; (4) The natural gas comes from cracking of the ancient oil reservoir and hydrocarbon generation of dispersed organic matter in source rocks, and the NNE-trending strike-slip fault is the dominant channel for vertical migration of natural gas; (5) Limestone cap rocks in the first and second members of Yingshan Formation provide direct sealing for the formation of gas reservoir there. On the basis of comprehensive analysis, it is pointed out that the Gucheng area has three grain shoal zones in the third member of Yingshan Formation in nearly S-N direction, which together with seven strike-slip fault zones in NNE direction control the development of shoal dolomite gas reservoir.

The distributed metadata management system utilizes multiple metadata servers (MDS) to store and manage a large amount of metadata. The system reduces the data load on each individual MDS by employing different mapping strategies to distribute the massive metadata across multiple MDS, thus minimizing the disk access frequency and improving the overall performance of the metadata management system. Typically, a hash function is used to map metadata keys to different MDS. However, when the feature values of the data are similar, the one-way nature of the hash function can result in data distribution imbalance, leading to performance degradation of the MDS. To address the performance degradation issue caused by uneven data distribution, this paper proposes a dynamic spatial partitioning and compressed Bloom filter-based metadata load balancing algorithm. The algorithm first constructs a hash bucket to organize the metadata keys, mapping the keys to different hash buckets using a hash algorithm. During the mapping process, the target hash bucket is dynamically adjusted based on the load condition of the MDS, and the mapping information of the metadata keys is sequentially stored within the corresponding hash bucket. When accessing metadata, the algorithm preprocesses the metadata keys using a compressed Bloom filter, and then performs a binary search within the specified hash bucket to retrieve the mapping information. Compared to recent metadata management algorithms, the proposed algorithm ensures load balancing of MDS even when key skewness occurs. Experimental results show that the algorithm achieves a 20% improvement in search performance compared to the optimal metadata management algorithm, with only a 2% increase in memory consumption. [ABSTRACT FROM AUTHOR]

In this study, polyethylene (PE) was used as the raw material, and polyhydroxyalkanoate (PHA), modified nano-CaCO3 and bagasse fiber(BF) were used as the composite fillers, and the nano-CaCO3/BF/PHA/PE composites were prepared by melt extrusion and injection molding. The effects of the optimal ratios of PHA, modified nano-CaCO3 and BF and their contents on the internal structure and properties of the composites were investigated by mechanical property tests, Fourier transform infrared spectroscopy (FTIR) analysis, thermogravimetric (TG) analysis, scanning electron microscopy (SEM) and other characterization methods. The results show that with 5% PHA, 5% BF, and 5% nano-CaCO3, the mechanical properties of the composites were optimal at 12.9 MPa, and the maximum thermal decomposition temperature of the nano-CaCO3/BF/PHA/PE composites reached 437 °C at this ratio, which was higher than the thermal decomposition temperature (453 °C) of the composites before modification. The study provides ideas for the green development of degradable polymer materials. [ABSTRACT FROM AUTHOR]

Objective: To accurately distinguish intact peanut, nut damaged peanut and epidermis damaged peanut. Methods: A peanut seed integrity detection scheme based on deep learning convolution neural network （CNN） was proposed. The peanut seed color selection system was established and a peanut seed image database was also established; The improved density peak clustering （DPC） algorithm was used to adaptively compress the CNN convolution kernel to effectively balance the network depth and operation efficiency; The improved sparrow search algorithm was used to optimize the CNN super parameter configuration and network structure, and the CNN model suitable for peanut grain integrity detection was obtained. Results: Compared with other detection methods, this scheme improved the recognition accuracy by about 5.41%~13.92%, and the detection time of single image of peanut grain was shortened by about 16.9%. Conclusion: This method effectively improves the accuracy and real-time of peanut grain integrity detection.

The patients with liver cirrhosis are often complicated with coagulation dysfunction, and blood hypercoagulable state is one of the manifestations. Blood hypercoagulable state is not only involved in thrombosis, the latest evidence confirms that it is also involved in liver injury, liver regeneration and liver fibrosis. This review attempts to discuss the mechanism of blood hypercoagulable state in liver cirrhosis, the role of intestinal microecological environment in it and the latest influence mechanism of blood hypercoagulable state in liver cirrhosis.To provide a new concept for the diagnosis and treatment of patients with liver cirrhosis.

In order to provide wheat quality information for wheat purchasing & storage companies and processing companies in Hebei Province and provide technical basis for the rational use of local wheat resources,The newly harvested wheat from the main wheat producing areas in Hebei Province from 2010 to 2019 was tested for quality indicators such as test weight,mass of 1000 grains,unsound kernel content,sprouted kernel content,moisture content,hardness index,falling number,wet gluten content,and protein content.The quality of wheat in Hebei Province in the past ten years was analyzed from three aspects:the annual change of each detection index,the comparison of the average value of the detection index of each city,and the comparison of the selection of the detection index of each city.The results showed that the quality of wheat was normal except for 2013 and 2018.The quality of wheat in 2013 was the worst in ten years.The test weight,mass of 1000 grains and falling number of wheat were all at the lowest values.The unsound kernel content and sprouted kernel content and moisture content were at the highest values.In the data of past ten years,the wheat in Xinji City has obvious comparative advantages in terms of high test weight,high mass of 1000 grains weight,low unsound kernel content,and high wheat hardness index.In addition,wheat from Handan,Xingtai and Shijiazhuang City has obvious comparative advantages in terms of high test weight.

With continuing breakthroughs in computational chemistry theory and substantial improvement of computation hardware performance, great progresses have been made in recent years in first principle-based prediction of 1H and 13C chemical shifts of organic molecules. Some methods have even been gradually applied for accurate prediction in complex molecular systems. In this paper, a density functional theory-based high-precision on-line chemical shift prediction platform for organic molecules is established, which provides on-line interactive service of chemical shift prediction for molecules with a molecular weight less than 800. The platform accelerates the mapping between nuclear magnetic resonance (NMR) spectra and molecular structures, and provides a powerful tool for efficient assignment of NMR spectra and accurate analysis of organic molecular structure.

Bile acids are synthesized from cholesterol in hepatocytes and play an important role in the absorption, transport and distribution of fat and fat soluble vitamins. They also act as important signal molecules to regulate metabolism and inflammatory response. The accumulation of bile acids in the body and the activation of bile acid related receptors can aggravate or alleviate the complications of liver cirrhosis such as hepatic encephalopathy, portal hypertension and peritonitis.

TEM, DSC and other techniques were used to characterize the heating aging precipitation behavior of 7050 aluminum alloy under compression pre-deformation conditions, and the influence law and mechanism of pre-deformation on heating aging precipitation were investigated. The results show that 7050 aluminum alloy can obtain excellent strength and corrosion resistance after pre-deformation heating aging, which can significantly shorten time and reduce energy consumption compared with traditional aging process. The pre-deformation greatly promotes the aging precipitation of 7050 aluminum alloy. The precipitate size increases rapidly as the increase of deformation during the same heating aging process, and its size distribution range increases rapidly too. The pre-deformation during heating aging process not only reduces the phase transformation activation energy of η' and η phases of 7050 aluminum alloy, but also accelerates the diffusion of solute atoms, which intensifies the Ostwald ripening and promotes the growth of precipitates. The calculation results show that the phase transformation activation energy of 7050 aluminum alloy gradually decreases with the increase of deformation. When the deformation amount increases from 0% to 18%, the phase transition activ-ation energy of η' and η phases decreases from 116.0 kJ/mol to 101.7 kJ/mol and 120.8 kJ/mol to 107.5 kJ/mol, respectively.

Nanofibers have the advantages of high strength, high specific surface area, ultra-fine size, high flexibility and biocompatibility, and are widely used in various fields. Polyacrylonitrile/carbon nanotube (PAN/CNTs) composite nanofibers with adsorption function for volatile organic compounds (VOCs) were prepared based on electrospinning technology. By optimizing the experimental parameters, such as spinning solution concentration, spinning voltage and receiving plate distance, the most suitable combination of parameters for PAN fibers in the electrospinning process was explored. The results show that when the concentration of spinning solution is 12%, the spinning voltage is 18 kV. When the distance between the receiving plates is 14 cm, the morphology of PAN fibers is regular, the size is uniform, and the average diameter is 200 nm. After the addition of CNTs, the fiber diameter increases to 400 nm, but the structure of PAN does not change. When the content of CNTs is 3%, the morphology of the fibers is the best. The adsorption experiment of VOCs shows that the adsorption efficiency of PAN fiber membrane for xylene gas increased to about 90% by the introduction of CNTs. [ABSTRACT FROM AUTHOR]

Background and objective Lung cancer screening is an effective measure to reduce lung cancer mortality. Currently, lung cancer screening is recommended internationally and nationally. China had launched a large-scale early diagnosis and early treatment of rural and urban lung cancer in 2009 and 2012. Yunnan Province participated in related projects in 2009 and 2014, but the results of large-scale lung cancer screening have not been reported in Yunnan Province. In this study, we participated in the National Key Public Health Program, Cancer Screening Program in Urban China and analyzed the results of lung cancer screening in 10,154 urban residents in Kunming, Yunnan Province from 2014 to 2018, and evaluated the screening effect of early diagnosis and treatment of lung cancer in urban. Methods A total of 31,824 people with high risk of lung cancer were evaluated with 40-74 year-old population in Kunming. A high-risk group underwent low-dose spiral computed tomography (CT) scan of the chest, and analyze the high risk rate and detection rate. A total of 150,535 questionnaires were completed in 5 years, and 31,824 people with high risk of lung cancer were evaluated. Results The high-risk rate was 21.14%. A total of 10,154 low-dose spiral CT screenings were performed, with a participation rate of 31.91%. The detection rate of intrapulmonary nodules was 22.28% (2,262/10,154), of which the detection rate of

Taking tight oil in Gaotaizi and Fuyu oil layers of the Upper Cretaceous Qingshankou Formation in northern Songliao Basin as an example, based on analyses of nuclear magnetic resonance and high pressure mercury injection, experiment methods of supercritical carbon dioxide displacement and extraction are firstly employed to quantify crude oil mobility in tight sand reservoirs with different lithologies and oil contents. The results show that, under the conditions of simulating the Cretaceous Qingshankou Formation in the northern Songliao Basin at a temperature of 76−89 °C and a pressure of 35−42 MPa, the lower limit of the porosity of the movable oil is 4.4%, and the lower limit of the permeability is 0.015×10−3 μm2. The lower limit of the average pore throat radius is 21 nm. On this basis, a classification standard for three types of tight sand reservoirs is proposed. Type I reservoirs are characterized by the movable fluid saturation larger than 40%, the movable oil ratio (ratio of movable oil to total oil) greater than 30% and the starting pressure gradient in the range of 0.3−0.6 MPa/m; Type II reservoirs are characterized by the movable fluid saturation in the range of 10%–40%, the movable oil ratio in the range of 5%–30% and the starting pressure gradient in the range of 0.6–1.0 MPa/m; Type III reservoirs are characterized by the movable fluid saturation less than 10% in general, the movable oil ratio less than 5%, and the starting pressure gradient greater than 1.0 MPa/m. The fluid mobility in tight sand reservoirs is mainly affected by diagenesis and sedimentary environment. Reservoirs with depth lower than 2 000 m are dominated by type I reservoir, whereas those with greater depth are dominated by type I and II reservoirs. Reservoirs in inner delta-front facies are dominated by type I reservoir, whereas those in outer delta-front facies and shore-shallow lacustrine facies are dominated by type II and III reservoirs. Key Words: northern Songliao Basin, tight oil, pore structure, crude oil mobility, displacement experiment, movable oil ratio, Upper Cretaceous Qingshankou Formation

ZnCl2 and SnCl2 were added to the AlF3-CsF eutectic flux, which can be used for connecting aluminum alloy sheet by self-brazing at medium temperature. The influence of the amount of ZnCl2 and SnCl2 and the size of the T-joint area on the interface microstructure and the self-brazing joint mechanical properties was investigated. The interface microstructure, chemical compositions, defects and tensile fractography of the self-brazing joints were analyzed by metallographic microscope, scanning electron microscope and energy dispersive spectroscopy. The results show that the joints are soundly bonded when both the mass fractions of ZnCl2 and SnCl2 are about 4%; the replacement reactions between Zn2+, Sn2+ of flux and Al atoms of base metal occur during brazing, then the liquid metals of Sn and Zn appear, a great degree of Zn which has high solid solution with Al spreads rapidly to the base metal; Sn is distributed along the interface forming a low melting point metal layer with Zn and Al; the brazing of joints with small area can be realized easily; there are a lot of dimples on the fracture surface and the tensile strength of the brazing joint reaches (58±5)MPa.

DOI: 10.3969/j.issn.1672-6731.2019.05.013

Over the past three decades,attacks exploiting Windows memory holes have emerged in an endless stream,and the usual means is to attack control-data to hijack the execution flow of the program.To this end,Microsoft has added layers of protection mechanisms to Windows to prevent such attacks.But at this stage,the defensive mechanisms deployed on Windows cannot prevent attacks against non-control-data.In view of the published articles lacking comprehensive study of Windows memory protection mechanism,a detailed introduction to Windows memory protection mechanism and its breakthrough techniques,and non-control-data protection research status was conducted.On this basis,the challenges of Windows memory protection were analyzed and the future of memory protection was discussed.

Currently, machine learning-based detectors are widely used to handle millions of Android malware, but they often suffer from poor anti-adversarial attack abilities. The research on the adversarial examples generation method of malware is helpful to promote the development of the field of malware detection. The adversarial examples generation technology in the black-box scenario is more in line with the real environment, but the effect is not good compared with the white-box scenario. To solve this problem, this paper proposes a black box malware adversarial examples generation method based on SNGAN, migrating the SNGAN approach to the malware domain from the image domain, adversarial examples are generated by the network of generator and replace detector iterative training, the training process is stabilized by spectral normalization. The proposed method can cheat the machine learning detectors by adding disturbance to the existing malware. Experimental results show that our method can avoid detection effectively from a variety of machine learning classifiers, and the feasibility and portability of the method are verified. [ABSTRACT FROM AUTHOR]

Tension-shear test was carried out on middle temperature self-brazing aluminum honeycomb cores after high temperature aging by micro mechanical test system, and the microstructure and component of the joints were observed and analyzed using scanning electron microscopy and energy dispersive spectroscopy to study the relationship between brazing seam microstructure, component and high temperature aging properties. Results show that the tensile-shear strength of aluminum honeycomb core joints brazed by 1060 aluminum foil and aluminum composite brazing plate after high temperature aging(200℃/12h, 200℃/24h, 200℃/36h) is similar to that of as-welded joints, and the weak part of the joint is the base metal which is near the brazing joint. The observation and analysis of the aluminum honeycomb core microstructure and component show that the component of Zn, Sn at brazing seam is not much affected and no compound phase formed after high temperature aging; therefore, the main reason for good high temperature aging performance of self-brazing aluminum honeycomb core is that no obvious change of brazing seam microstructure and component occurs.

The current status of research on convective heat transfer and thermal economy of hybrid Nano fluids in heat exchangers is reviewed. The influencing factors and variation mechanisms of convective heat transfer performance parameters" total heat transfer coefficient, convective heat transfer coefficient, Nu number) are introduced. The thermal economy" thermal efficiency, entropy production, fire use loos and second law efficiency) of mixed Nano fluids in heat exchanger applications is analyzed. [ABSTRACT FROM AUTHOR]

Taking Chinese fir wood from plantation as the research object, three technological parameters including hot-pressing temperature (160, 180, 200 °C), hot-pressing time (20, 30, 40 min) and compression ratio (30%, 40%, 50%) were selected, and the compression densification modification test of Chinese fir was carried out by using the full factor experimental design. Based on the mechanical properties, microscopic morphology and crystallinity of wood, the effects of different processing parameters on wood properties were analyzed, and the densification process parameters of Chinese fir wood were optimized. The results showed that the properties of the densified wood prepared by Chinese fir were better under the technological conditions of hot pressing temperature of 180 °C, compression ratio of 50%, and pressing time of 40 min. The flexural strength, flexural modulus of elasticity, tensile strength, and hardness of the densified Chinese fir were 130.4 MPa, 12 338 MPa, 113.1 MPa and 1 631 N respectively, which increased by 112%, 113%, 44%, and 55% compared to the untreated wood. The scanning electron microscope observation showed that almost all the early wood cells were crushed, and there were regular folds along the direction of the wood ray, while some of the late wood cells were crushed, and most of them kept the original cavity structure. The hardness and elastic modulus of the cell wall of the densified wood were 16.7% and 45.7% higher than that of the untreated wood. The crystallinity of wood after compression treatment increased. The crystallinity of cellulose in the untreated wood and compressed Chinese fir was 46% and 53%, respectively. [ABSTRACT FROM AUTHOR]

The experiment was to study the effect of different levels of fermented Chinese herbal by-products on growth performance, serum biochemical index, antioxidant capacity and immune function of Songliao Black pigs during finishing period. Fifty Songliao Black pigs (93.85±4.11) kg at late finishing stage were randomly divided into five groups, with five replicates in each group and two pigs in each replicate. Songliao Black pigs in control group were fed with basic diet. Experimental group I, group II, group III and group IV were supplemented with 1% fermented Chinese herbal by-products, 1% unfermented Chinese herbal by-products, 3% fermented Chinese herbal by-products and 3% unfermented Chinese herbal by-products in basic diet, respectively. The pre-test lasted for 6 d and the formal test lasted for 54 d. The results showed that compared with control group, the ADG of Songliao Black pigs in group I and group III was increased by 17.42% and 24.69%, respectively, and F/G was decreased by 5.05% and 10.33% (P<0.05), respectively. Compared with control group, the IgA content of Songliao Black pigs in group I and group III was increased by 5.30% and 13.49%, respectively. Compared with control group, the serum IGF-1 content and T3 content of Songliao Black pigs in group III were increased by 14.00% (P<0.05) and 38.19% (P<0.05), respectively. Compared with control group, the serum MDA content of Songliao Black pigs in group III was decreased by 50.76% (P<0.05). The experiment indicates that adding 3% fermented Chinese herbal by-products in diet can improve the antioxidant capacity and immune level of body, increase the secretion level of growth hormones, and improve the growth performance of Songliao Black pigs during finishing period. [ABSTRACT FROM AUTHOR]

For carbon fiber reinforced polymer (CFRP) composites, the effects of interfacial sliding of two-dimensional multilayer graphite oxide (GO) on the damping characteristics of CFRP composites were studied. The damping loss factor of CFRP was measured by dynamic mechanics analyzer, and the effect of GO on the damping performance of CFRP was studied under different scanning modes (temperature, frequency and strain). The results show that the deposition of GO on the surface of carbon fibers can enhance the damping characteristics of CFRP over a wide range of temperature, frequency, and strain domains. A finite element parametric analysis based on strain energy method is proposed in ANSYS, and the interface characteristics of multi-layer GO are obtained by combining with experimental data. The damping parameters of GO interface can be used to predict the damping characteristics of multilayer carbon nano materials modified composites under different service conditions. [ABSTRACT FROM AUTHOR]

The stress relaxation behavior and springback equation of 7050 aluminum alloys during the age-forming process were studied through self-designed uniaxial tension device. The results show that in traditional aging temperature, the stress relaxation curve of 7050 aluminum alloys exhibits a classical logarithmic decrement curve. The stress relaxation process can be divided into three stages, which are the initial stress decayed fast stage, the subsequent stress slowly decayed stage and the stress constantly maintained stage, respectively. Stress relaxation limit of 7050 aluminum alloys decreases with increasing aging temperature. The threshold stress presents during the stress relaxation process due to the interaction between precipitation behavior and dislocation creep of 7050 aluminum alloys. The stress relaxation equation of 7050 aluminum alloys is obtained through resolving the feature and Taylor equation of relaxation process, and using the stress relaxation equation can precisely predict the springback of workpiece after age-forming.

Objective To explore the curative effect and parameter settings of vagus nerve stimulation (VNS) therapy in refractory epilepsy. Methods VNS was performed in 71 patients with drug-resistant epilepsy, and McHugh classification was used to evaluate the curative effect of VNS. Programmable pulse parameters included output current, frequency, pulse width, and On/Off times. The optimum settings for each patient should balance the goals of maximizing efficacy, minimizing side effects, and preserving battery life. Results After operation, all patients were followed up for 3-56 months (median 22 months), and experienced a significantly reduced seizure frequency compared with before operation [18 (3, 92) vs 30 (5, 145) times/month; Z = 826.500, P = 0.000]. In these patients, 20 cases (28.17% ) had < 50% reduction of seizure frequency, and 51 cases (71.83% ) had ≥ 50% reduction of seizure frequency, including 27 cases (38.03%) with ≥ 80% reduction and 14 cases (19.72%) with seizure free. Seizure termination or seizure diminution was reported in 8 patients (11.27% ) after using magnet. Conclusions VNS is a safe and effective therapy in medically refractory epilepsy. Optimized output current is generally 1.00-1.75 mA, however, 0.75 mA is also an efficient current. Besides, parameter settings should be considered to reach the maximizing efficacy. DOI: 10.3969/j.issn.1672-6731.2015.09.008

The experiment was conducted to study the effect of different solvents on extraction of active substances from Veronica indica. Veronica indica was used as raw material. The total phenols and flavonoids of Veronica indica were extracted from roots, stems and leaves with five different solvents using ultrasonic assisted extraction method. The antioxidant activities of extracts were determined, and the correlation between antioxidant capacity of different solvent extracts and active substances was evaluated. The results showed that different polar solvents had different extraction effects on different parts. The content of total flavone and total phenol of 60% ethanol extract were the highest, which were 10.22 and 10.69 mg/g, respectively. Ethanol at root (99.7%) total flavonoid content of extract was the highest (7.65 mg/g), and the total phenolic content of the methanol extract was the highest (3.92 mg/g). The total flavonoid content of stem water extract was the highest (6.89 mg/g), and the total phenolic content of 60% ethanol extract was the highest (3.36 mg/g). The study indicates that there is a good dose-effect relationship between the content of active substances in Veronica indica and its antioxidant activity. The extraction quantities of total flavonoids and total phenols from Veronica indica are ranked as follows: leaf > root > stem. 60% ethanol solution is the best solvent to extract total flavonoids and total phenols from Veronica indica. [ABSTRACT FROM AUTHOR]

This work presents the research progress of AGS resource recovery technology in recent ten years, and mainly summarizes methods to extract the high-value-added product in EPS from AGS, compares relative merits of different extraction methods and potential applications of different high-value-added products. This will provide technical supports for low-carbon efficient wastewater treatment process with AGS technology as the core technology, and provide valuable research thoughts for wastewater resource recovery. [ABSTRACT FROM AUTHOR]

The abundance of microplastics in freshwater systems in China and the biotoxicity of microplastics in the world were reviewed. The analysis and identification methods of microplastics still have many limitations. Improving technical methods is of great significance for studying the aggregation and migration process of microplastics in environmental media. The establishment of an ecotoxicological assessment methods for microplastics and its compound pollution system and the enrichment of basic database will be a hot spot in this field in the future. Scholars and experts should combine international front scientific issues and analysis and identification difficulties, improve the recycling and waste management of plastic products, strengthen the detection of the concentration of microplastics in the environment, and explore the transfer efficiency of microplastics pollutants between different nutritional levels, continuously improve the biological toxicity effects and ecotoxicological mechanisms of microplastics and their compound pollutants. [ABSTRACT FROM AUTHOR]

For problems that high temperature caused by bad contact of isolator of mine-used high-voltage distribution equipment usually leads to faults and the faults are hardly detected, a design scheme of on-line monitoring system for temperature of isolator contact of mine-used high-voltage distribution equipment was put forward and software designs of lower computer program and on-line monitoring program based on LabVIEW of the system were introduced emphatically. The test result showed that the system can monitor temperature of isolator contact of mine-used high-voltage distribution equipment real-timely and remotely with error less than 1 ℃, which can meet requirement of actual project. Besides, the system has functions of fault diagnosis and early warning according to monitored temperature signal.

The calculation of the distance to target center is important in the trajectory quality inspection, and its core is to solve the coordinate of the entry point to targets. The entry point is a cross point of trajectory and a spatial plane: in directional wells, this plane is the horizontal plane; in horizontal wells, it is the vertical plane of the target axis. A scanning algorithm for target-entry interval is given according to the concept of directed distance from point to plane. This method can fast determine the target-entry interval. This article studies the numerical iterative method-bisection and its convergence performance, which is used to solve the key-parameter equation of target-entry point, and provides detailed formulas for three interval curve types of spatial arc, cylindrical helical, and natural curve. Theoretical and practical cases show that the bisection method is very effective in obtaining the numerical solution of target-entering point. Key words: target center distance, mathematical model, bisection method, directional well, horizontal well

Tannic acid is a kind of plant polyphenol compound, which widely exists in roots, stems and leaves of plants. Hydrolyzed tannic acid has many biological functions, such as anti-diarrhea, anti-oxidation, anti-inflammatory, bacteriostasis, etc. It plays an important role in maintaining animal intestinal health and improving animal growth performance. The paper summarizes the physicochemical properties, biological functions and application of hydrolyzed tannic acid in animal husbandry, to provide reference for its rational application in animal husbandry. [ABSTRACT FROM AUTHOR]

Corn-soybean meal diet is one of the common types of livestock and poultry diets in China. In recent years, the stock of corn has declined year by year, leading to the high price of corn and the rising breeding cost. Therefore, it is of great significance to adopt non corn-soybean meal diets for the development of Chinese feed industry. Sorghum has relatively high energy value and protein content, which can replace part of corn and soybean meal in livestock and poultry diets, reduce the use of corn and soybean meal, and alleviate the pressure of insufficient supply of feed materials. The paper analyzes the nutritional value and anti-nutritional factors of sorghum, and expounds the application progress of sorghum in pig production at home and abroad in recent years, to provide reference for the application of sorghum in pig feed production. [ABSTRACT FROM AUTHOR]

In view of problem that it is difficult to measure impact frequency of pneumatic anchor drill, the paper proposed a design scheme of new type of measuring instrument of impact frequency of pneumatic anchor drill. The instrument uses pressure sensor to collect impact signal of drill, and uses voltage comparator and monostable trigger to process the signal which is input into single-chip microcomputer to count impact frequency of drill. The actual application showed that the instrument can measure impact frequency of drill accurately and easily.

A high performance liquid chromatographic (HPLC) method was developed for simultaneous determination of seven antioxidants in plastic eye drops bottles and their migration in pharmaceuticals. The samples were ultrasonically extracted and separated by Shim-pack GIST C18 chromatographic column with methanol-water as mobile phase for gradient elution. The flow rate is 1.0 mL/min, the column temperature is 35 °C, the detection wavelength is 276 nm, and the injection volume is 10 μL. The results show that the seven antioxidants have a good linear relationship in the corresponding mass concentration range (R²=0.999 9). The detection limit is 0.15~0.31 μg/mL, and the lower limit of quantification is 0.53°C1.04 μg/mL. The recoveries of extraction test and migration test are 87.02%*105.28% and 84.79%~104.77%, respectively. The relative standard deviation (RSD) of each recovery is not more than 4.80%. Six antioxidants are detected in plastic medicinal eye drops bottles with the content of 3.86~203.54 μg/g. Antioxidant is not detected in migration test eye drops. The method is simple, accurate and reliable, and can be used to investigate the antioxidants in plastic medicinal eye drops bottles and their migration in medicinal. [ABSTRACT FROM AUTHOR]

In order to explore the effects of ecological ditch on reducing agricultural non-point source nitrogen and phosphorus in different observation periods and identify the key reduction period in Guangxi, nitrogen and phosphorus concentration was monitored at Dongcun Village in Xing'an County from May 2019 to April 2021. Based on the monitored data, the variations of nitrogen and phosphorus concentration, nitrogen composition and reduction efficiency were analyzed in different observation periods of dry seasons, rainy seasons, spring, summer, autumn and winter. The results showed that the average concentrations of ammonium nitrogen (NH4+-N), nitrate nitrogen (NO3--N), total nitrogen (TN) and total phosphorus (TP) during the whole monitoring period were 5.62~19.84, 2.38~4.00, 15.30~28.18 and 0.50~1.26 mg/ L, respectively. The average ratios of NH4+-N and NO3--N concentration to TN concentration at the monitoring points along the ecological ditch were 0.04~0.90 and 0.02~~0.66, respectively, and the average ratios of NH4+-N in autumn, winter and dry season was 0.41~0.90, which were significantly higher than those in other seasons. The reduction efficiency relative to the water inlet of each monitoring point along the ecological ditch was obvious, and the reduction efficiency of NH4+-N, NO3--N, TN and TP were 0.31%~1.10%, 0.07%~1.69%, 0.31%~ 1.07% and 0.30%~0.91%, respectively. Autumn and winter were the key periods for the reduction of NH4+-N, TN and TP, while the reductions of NO3--N were the highest in summer and autumn. [ABSTRACT FROM AUTHOR]