Preliminary Study on in Vitro Germination of Yangmei Pollen

[Objectives]To explore the conditions for in vitro culture of Yangmei pollen.[Methods]Experiments were conducted on the germination characteristics of three types of Yangmei pollen using in vitro culture and germination method.[Results]The suitable medium ratio for the germination of Yangmei pollen was 10%sucrose+0.01%borax+1%agar;the cultivation temperature of 30℃was more suitable for the germination of Yangmei pollen than 25℃;through analysis of variance,among the three types of Yangmei pollen,pollen of male 1 had the strongest viability,and it was the better pollination type.[Conclusions]The research could provide certain basis for introduction and cultivation of Yangmei and improving hybrid breeding effect.

Theoretical and numerical analysis of coal dust separated by centrifugal force for working and heading faces

In order to meet engineering needs of Chinese underground coal mines,a new dust-collecting fan,a device of dust separated by centrifugal force in driven cyclone passageway(DCCP)was designed.In centrifugal dust removal section(CDRS)of DCCP,a general equation is derived from the principle of force equilibrium.According to CDRS structure parameters and fan running parameters,the general equation is simplified,and the simplest equation is calculated numerically by MATLAB.The calculation results illustrate that increasing quantity of air current is against dust removal,but it is beneficial to dust removal by increasing the radius of driven spiral blade and increasing the particle diameter of coal dust.The conclusions show that the dust-collecting structure parameters coupled with the fan running parameters is a novel optimization approach to dust-collection fan for working and heading faces,which is especially suitable for Chinese underground mines.

Effects of structural and operating parameters of ECP fan on dust particles removed in the transition flow regime

An enclosed cyclone passageway(ECP)dust-collecting fan is discussed.The ECP fan separates dust by centrifugal force originating from a driven spiral airflow,and its design takes the constraints of Chinese underground coal mines into consideration.Using the force equilibrium law,a general equation for dust removal in the centrifugal dust removal section(CDRS)of the ECP fan is deduced.This general equation is simplified using the CDRS structure and the fan operating parameters and is analysed numerically.The attractive results show that increases in the airflow rate of the fan,the structural ratio of the ECPs and the radius of the extended axis can improve the dust removal performance of the CDRS.Furthermore,the effects of the structural ratio and the radius on dust removal dominate over that of the flow rate,and the effect of the structural ratio is more significant than that of the radius.

Research on Surface Defect Detection Method of E-TPU Midsole Based on Machine Vision

In the industrial production of expanded thermoplastic polyurethane (E-TPU) midsoles, the surface defects still rely on manual inspection at present, and the eligibility criteria are uneven. Therefore, this paper proposes an E-TPU midsole surface defect detection method based on machine vision to achieve automatic detection and defect classification. The proposed method is divided into three parts: image preprocessing, block defect detection, and linear defect detection. Image preprocessing uses RGB three channel self-inspection to identify scorch and color pollution. Block defect detection uses superpixel segmentation and background prior mining to determine holes, impurities, and dirt. Linear defect detection uses Gabor filter and Hough transform to detect indentation and convex marks. After image preprocessing, block defect detection and linear defect detection are simultaneously performed by parallel computing. The false positive rate (FPR) of the proposed method in this paper is 8.3%, the false negatives rate (FNR) of the hole is 4.7%, the FNR of indentation is 2.1%, and the running time does not exceed 1.6 s. The test results show that this method can quickly and accurately detect various defects in the E-TPU midsole.

Winter estimation of surface roughness length over eastern Qinghai-Tibetan Plateau

Based on the Monin-Obukhov similarity theory, a scheme was developed to calculate surface roughness length. Surface roughness length over the eastern Qinghai-Tibetan Plateau during the winter season was then estimated using the scheme and eddy covariance measurement data. Comparisons of estimated and measured wind speeds show that the scheme is feasible to calculate surface roughness length. The estimated roughness lengths at the measurement site during unfrozen,frozen and melted periods are 3.23×10-3, 2.27×10-3 and 1.92×10-3 m, respectively. Surface roughness length demonstrates a deceasing trend with time during the winter season. Thereby, setting the roughness length to be a constant value in numerical models could lead to certain degree of simulation errors. The variation of surface roughness length may be caused by the change in land surface characteristic.

Water film area and dust removal efficiency of string grilles:a theoretical analysis

Based onmultiphase flowtheory and capillary mechanics,the dimensionless bond number expression of the influence of string grille wire spacing on droplet spreading is derived.Taking a liquid film formed by spreading droplets based on Kelvin correlation,the Young-Laplace equation,and the Hagen-Poiseuille law,an equation for calculating the thickness and height of the liquid film is established with temperature,relative humidity and molar volume of liquid phase as independent variables.According to the theory of string grille filtration and dust removal,a dust removal efficiency calculation model covering the wet string grille wire group is constructed based on the liquid film thickness,height,wire diameter,water film area,and vortex shedding frequency.Finally,a theoretical analysis of the influence of water film area on the efficiency of wet string grille dust removal is carried out based on the spray pressure and the ratio of string grille wire distance to wire diameter.It is found that the effect of spray pressure on water film area and dust removal efficiency is more significant than the string grille wire distance diameter ratio.Moreover,the optimized combination of wet string grille wire distance diameter ratio 0.84,wind speed 3m/s and spray pressure 0.8 MPa is found,which could provide an important reference for engineering applications.

Effects of Activating Blood Circulation to Resolve Blood Stasis and Glucosamine Capsules Therapy on the Expression of Matrix Metalloproteinase in Post-traumatic Knee Osteoarthritis

[Objectives] To observe the clinical effects of activating blood circulation to resolve blood stasis and glucosamine hydrochloride capsules therapy on post-traumatic knee osteoarthritis treatment,to measure the expression of matrix metalloproteinase in post-traumatic knee osteoarthritis patients before and after treatment,and to explore its relevant molecular mechanisms. [Methods]A total of 60 patients with posttraumatic knee osteoarthritis in early stage in Affiliated Hospital of Shannxi University of Chinese Medicine from January 2015 to December2017 were selected and randomly divided into the control group( n = 30) and the observation group( n = 30). The control group was given oral administration of glucosamine hydrochloride capsules for 6 courses of the treatment. The observation group was using the activating blood circulation to resolve blood stasis therapy for 6 courses of treatment. The recovery of traumatic knee osteoarthritis and the symptom of traditional Chinese medicine( TCM) in 2 groups was compared before and after treatment. The symptoms and the quantitative assessment rating scale of knee osteoarthritis,the pain index of knee and the TCM symptom scores were recorded in both groups. And the synovial fluid and serum of patients were collected to detect the expression of matrix metalloproteinase. [Results]The symptoms and the quantitative assessment rating scale of knee osteoarthritis,the pain index of knee and TCM symptom scores of the 2 groups in the 1 st week,the 12 th week and the 24 th week after the treatment were significantly lower than those before the treatment,and the difference was statistically significant( P < 0. 05). Two therapeutic methods had certain therapeutic effects on the recovery from traumatic knee osteoarthritis,and could significantly improve the TCM syndrome. There were better therapeutic effects on oral decoction of traditional Chinese medicine than oral glycosaminoglycans hydrochloride capsules on treating traumatic knee osteogenesis( P < 0. 05). The expression level of MMP3 was decreased significantly in both groups( P <0. 001),while the expression level of MMP13 had no significant change in both groups( P >0. 05). The expression level of MMP1 was decreased significantly in the observation group( P < 0. 001),but there was no significant change in the control group after treatment( P >0. 05). [Conclusions]Two treatment methods have been effective in this clinical study. We found that the expression level of MMP3 was decreased significantly after treatment in 2 therapies,which can be clinically applied.

A New Digital Image Encryption Algorithm Based on Improved Logistic Mapping and Josephus Circle

Digital image encryption based on Joseph circle and Chaotic system has become a hot spot in the research of image encryption. An encryption algorithm based on improved Josephus loop and logistic mapping is proposed to scrambling blocks in this paper. At first, the original image is scrambled by using logistic mapping to obtain the encrypted image, and then the encrypted image is divided into many blocks. Finally, the position of the blocked image is scrambled by using the improved Josephus ring to get the encrypted image. According to the experiments, the information entropy of the encrypted image reaches 7.99 and the adjacent correlations in three directions are within ±0.1. The experimental results show that the proposed algorithm has advantages of large key space, high key sensitivity and can effectively resist the attacks of statistical analysis and gray value analysis. It has good encryption effect on digital image encryption.

国际学习分析技术研究进展与趋势分析——基于2014年至2016年Journal of Learning Analytics论文分析

学习分析技术是采集与学习活动相关的学习者数据,并运用多种方法和工具全方面解读数据的技术,它能够记录分析学习环境和学习轨迹,进而发现学习规律,预测学习结果,为学习者提供相应的学习策略,促进有效学习。本研究选取Journal of Learning Analytics期刊2014年至2016年发表的112篇文章作为样本,梳理了学习分析技术的内涵和特点,归纳分析了六类热点研究主题,分别是学生日志数据分析、在线话语数据分析、学习评价数据分析、多模态数据分析、学习预警数据分析、伦理隐私数据分析。最后,从分析技术、跨学科研究、情感数据、多模态数据、基础教育应用五个方面,探讨了学习分析技术在教育教学应用方面的研究趋势。

Constructing zwitterionic nanofiber film for anti-adhesion of marine corrosive microorganisms

A zwitterionic nanofiber film was constructed through combining zwitterionic polymer with anodic aluminum oxide template for anti-adhering typical marine corrosive microorganisms,i.e.Pseudomonas aeruginosa,Desulfovibrio vulgaris and Chaetoceros muelleri.Results showed that the fabricated zwitterionic polymers film has fibrous nanostructure with uniform distribution and super hydrophilia.This film has wide anti-adhering properties,and it can effectively reduce the attachment of these three microorganisms by more than 99%.Moreover,the adhesion of extracellular polymeric substances secreted from these three microorganisms are also inhibited,which is one reason for the fabricated nanofiber film with antiadhesion characteristic of microorganisms.This research provides valuable information for solving the problem of microbial adhesion on metal surfaces in the marine environment.