Fine Characterization and Analysis of Drying Strain of the ELM Board via DIC Technology

In this paper,the occurrence and development mechanism of strain on the cross-section during the wood drying is explored.Therefore,strain regularity on the cross-section of 50 mm thickness elm(Ulmus rubra)board at the temperature of 40℃and 80℃is detected via digital image correlation technology.Hence,the difference between tangential and radial strain at surface and core layers was denoted.The results showed that strain distribution in the width direction of the board is uneven.Moreover,a large drying shrinkage strain occurs at the near-core layer,while the maximum strain difference reaches 4.08%.Hence,the surface of the board is cracked along the thickness direction.The radial strain of the board is higher than the tangential strain in the early stage of drying,while these strains are reversed in the later stage of drying.The temperature is related to the difference between the tangential and radial strains of the elm board.These differences at the core layer are larger than those of the surface layer.The conducted research results provide a theoretical basis for process optimization.

Fractal characterization for the mining crack evolution process of overlying strata based on microseismic monitoring technology

In order to study the evolution laws during the development process of the coal face overburden rock mining-induced fissure,we studied the process of evolution of overburden rock mining-induced fissures and dynamically quantitatively described its fractal laws,based on the high-precision microseismic monitoring method and the nonlinear Fractal Geometry Theory.The results show that:the overburden rock mining-induced fissure fractal dimension experiences two periodic change processes with the coal face advance,namely a Small→ Big→ Small process,which tends to be stable;the functional relationship between the extraction step distance and the overburden rock mining-induced fissure fractal dimension is a cubic curve.The results suggest that the fractal dimension reflects the evolution characteristics of the overburden rock mining-induced fissure,which can be used as an evaluation index of the stability of the overburden rock strata,and it provides theoretical guidance for stability analysis of the overburden rock strata,goaf roof control and the support movements in the mining face.

Functional Characterization of Bifidobacteria of Human Origin: A Case Study by the Students of Food Science and Technology of the University of Foggia (Southern Italy)

The aim of this paper was to study the potential technological and probiotic properties of bifidobacteria isolated from human feces. Bifidobacteria, naturally present in the dominant colonic microbiota, represent up to 25% of the cultivable faecal bacteria in adults and 80% in infants. Bifidobacteria have been shown to adhere and colonize in high numbers different types of cultured intestinal epithelial cells;moreover some authors reported that some strains are able to stabilize the intestinal microbiota during and after antibiotic therapy, modulate the immune system, protecting against chemically induced intestinal inflammation and reducing symptoms of colitis. Eight isolates of bifidobacteria were studied to assess their technological and probiotic traits;the technological characterization relied on the assessment of enzymatic activities (proteolytic and lipolytic activity), growth under various conditions (pH, temperature and addition of salt), acidifying ability and metabolism (arginine deamination, esculin, esculin hydrolysis and citrate metabolism). The study of the probiotic characteristics focused on the evaluation of the survival at low pH and with bile salts added, antibiotic resistance, and hydrophobic properties. As a result of this process, two promising strains were selected for further studies.

Rock mass structural recognition from drill monitoring technology in underground mining using discontinuity index and machine learning techniques

A procedure to recognize individual discontinuities in rock mass from measurement while drilling(MWD)technology is developed,using the binary pattern of structural rock characteristics obtained from in-hole images for calibration.Data from two underground operations with different drilling technology and different rock mass characteristics are considered,which generalizes the application of the methodology to different sites and ensures the full operational integration of MWD data analysis.Two approaches are followed for site-specific structural model building:a discontinuity index(DI)built from variations in MWD parameters,and a machine learning(ML)classifier as function of the drilling parameters and their variability.The prediction ability of the models is quantitatively assessed as the rate of recognition of discontinuities observed in borehole logs.Differences between the parameters involved in the models for each site,and differences in their weights,highlight the site-dependence of the resulting models.The ML approach offers better performance than the classical DI,with recognition rates in the range 89%to 96%.However,the simpler DI still yields fairly accurate results,with recognition rates 70%to 90%.These results validate the adaptive MWD-based methodology as an engineering solution to predict rock structural condition in underground mining operations.

Major Cultivation Technology of HQ No.1, a New Flue-cured Tobacco Cultivar

The transplanting period, density, the number of left leaves and fertilizer amounts of HQ No.1 were explored in Hengyang. The results showed that with transplanting periods of March 5-March 15, and planting space of 120 cmx（50-60） cm, agronomic and economic characters of tobaccos showed insignificant differences. Specifically, plant height was growing upon the number of left leaf and fertilizer amount; tobacco yield and output value kept increasing upon fertilizer, and both reached maximums with pure N at 195 kg/hm^2, showing significant differences with the treatment of pure N at 135 kg/hm^2; the number of left leaf had the least effects on agronomic and economic characters of tobaccos. The research indicated that highly-qualified HQ No.1 can be produced, given that tobaccos are transplanted during March 10-March 15, planting density of 15 000-16 500 seedlings/hm^2, the number of left leaves of 22-24 leaves per seedling, and pure N of 150-165 kg/hm^2 in Hengyang.

Preparation and characterization of uniform circinate aggregates of sheet ZnO nanoparticles

Uniform circinate aggregates of sheet ZnO nanoparticles with a specific surface area of 24 m^2·g^-1 were prepared by the direct precipitation method.The circinate aggregates were hexagonal ZnO,with the wall thickness ranging from 0.5 to 1 μm and the diameter ranging from 5 to 10 μm.The backs of the circinate aggregates were regularly arranged by numerous sheet ZnO nanoparticles with a thickness of 30-80 nm and a diameter of 300-400 nm.The precursors were aggregates of sheet Zn5（CO3）2（OH）6 nanoparticles,which were decomposed into ZnO by calcining in air in the range of 200-285°C,and the ZnO retained the similar special structure.The C2H5OH content had a significant effect on the formation of sheet ZnO.The centripetal force,the Van der Waals force,and the hydrogen bond were deduced as the driving forces of the formation of circinate.

Foundry Coating Technology: A Review

The importance of foundry coating in improving the surface quality of castings cannot be over emphasized. The application of mould and core washes creates a high thermal integrity barrier between the metal and the mould resulting in the reduction of the thermal shock experienced by the sand system. These thermal shock leads to series of surface defects such as veining/finning, metal penetration, burn-on/in, scab, rat tail, erosion etc. The use of coatings reduces the tendency of occurrence of these defects. However, the understanding of the coating, its components, characteristics and mechanism of action is important. In this review, a detailed description of these topics and examples are provided where necessary. A potential area of research in foundry coating development, using sol-gel process is suggested. The application of sol-gel technology in the development of foundry coatings is a novel approach.

Bifidobacteria as Potential Functional Starter Cultures: A Case Study by MSc Students in Food Science and Technology (University of Foggia, Southern Italy)

This research paper was the results of activity of MSc students of Food Science and Technology, attending the class “Biotechnology of Functional Starter”. Five strains of bifidobacteria (Bifidobacterium animalis subsp. lactis;B. longum subsp. infantis;B. breve;B. animalis subsp. animalis;B. bifidum) were evaluated in order to assess their suitability as functional starter cultures, by studying the following technological and probiotic traits: growth at different temperatures, NaCl amounts and pH values;acidifying ability;metabolism (arginin deamination, esculin hydrolysis, acetoin production);survival at low pH and in presence of bile salts;hydrophobic properties;antibiotic resistance. After laboratory assays and strain selection through a multivariate analyses, it was highlighted that B. longum subsp. infantis and B. animalis subsp. lactis represent a good compromise as potential functional starter cultures, as B. animalis subp. lactis showed a high growth index at pH 5 and good values at 25?C and 30?C, as well as the minimal viability loss at pH 2.5. B. longum subsp. infantis DSMZ 20088 was the best microorganism for its growth index in presence of 6.5% of salt added and at 25?C and 30?C.

Characterization of Fundamental Logics for the Sub-Threshold Digital Design

Digital circuits operating in the sub-threshold regime consume the least energy. The strict energy constraints are desired in the applications which work at the lowest possible supply voltage. On the other hand, the conventional design flow utilizes the technology library provided by the foundry with a fixed voltage boundary, which causes problems when the supply scales down to the sub-threshold regime. In this paper, we present a design methodology to characterize the existing cell library with Liberty NCX to facilitate the standard design flow. It is demonstrated in 0.13 μm complementary metal-oxide-semiconductor （CMOS） technology with the supply voltage of 300 mV.

Study on the detection methods of S&T frontier from the multi-dimensional perspective

The development of network and information technology has brought changes to the information environment.The sources of information are becoming more diverse,and intelligence acquisition will be more complicated.The intelligence reflected by different dimensions of scientific and technologi-cal(S&T)data will have their own focuses.It has become inevitable to carry out the multi-dimen-sional research of S&T frontier,which is also a current research hotspot.This paper uses quantita-tive and qualitative research methods to conduct research and analysis of S&T frontier detection from three dimensions including S&T research projects,S&T papers and patents,and proposes related re-search methods and development tools.This work analyzes the S&T frontiers in the field of artificial intelligence and draws conclusions based on the analysis results of real and effective S&T data in three dimensions.

Breeding and High-yield Cultivation Technology of Wuqing No.1, a New Cultivar of Black Soybeans

The research introduced selection and breeding process, characteristics and high-yield cultivation technology of Wuqing No.l. Wuqing No.l, also named Gaoyou black soybean, is bred based on Danbo black soybean introduced from Japan in 1996 by Gaoyou Vegetable Cultivation Technology Station and Yangzhou Agricultural Technology Promotion Station. It was named in 2014 by Jinagsu Crop Cultivar Approvement Committee. The cultivar is high-yielding with high quality, big seeds, high resistance to stress, as well as high health-care value.

Differences Among Industrial Companies in Their Innovative Efforts and Competitiveness： On How Size, Technological Level and Subcontractor Character Matter

The aim of this research is to test to what extent do the classifying variables of company size, technological level and subcontractor nature moderate on the causal relationship between a finn＇s innovative capacities and its competitiveness. To this end, we use a random sample of 861 manufactttring f＇Lrms with 10 or more employees from the Basque Autonomous Community （in Spain）, accounting for 26.29% of the population. Maximum sampling error is 2.87% for a 95% confidence interval. We start from a competitiveness general model of the firm, and set out under the resource based view of the finn, which had been previously tested and validated by Martinez （2009） for the whole sample. The model is formed with the constructs of management capabilities, innovative capabilities, marketing capabilities, quality capabilities, current competitiveness and future competitiveness. From this point, we test a set of alternative hierarchical models both for the total sample and for different divisions in sub-samples, according to the intervals of size in number of employees, OECD technological levels and firms＇ subcontractor character. The innovative capabilities construct is reflected in the items of radical product innovation, incremental product innovation, innovation in the production process, innovation in marketing, management innovation and the efforts in company workers＇ training and development. From all these items, previous descriptive data analysis showed that although product radical innovation was the most representative capability for superior innovativeness, it was at the same time the least evident from all the aforementioned items in the case of the analyzed Basque industrial companies. The analysis of results led us to conclude that the factor of innovative capabilities was the most influential on current competitiveness among the whole sample. In particular, as regards the size factor, this positive effect dilutes in the case of smaller companies. In the same manner, whereas in the case of the companies with higher technological level it is verified that the factor of innovative capabilities reveals crucial, in the group of fhans with lower technological level the most relevant factor is quality. Also, the same effect is evidenced for the case of the subcontractor/non-subcontractor nature of the finns： The first ones show quality as the most relevant construct while for the second ones it is the innovative capabilities.

基于孪生神经网络的楔形环连接结构预紧状态辨识

楔形环连接结构由于其连接简单可靠、同时兼具节省空间及减重的优势,常被应用于鱼雷、航天飞行器等武器装备。针对楔形环连接结构预紧状态辨识方面存在的机理模型复杂、样本量小且类别不平衡的问题,提出了一种基于孪生神经网络模型的预紧状态辨识方法。为提高模型训练效率和效果,首先利用时频处理技术进行孪生神经网络模型特征增强,基于增强特征建立了3层孪生神经网络分类模型,实现楔形环预紧状态宏观分类。同时,为指导楔形环精密装配,通过特征可视化技术,深入分析了孪生神经网络训练过程特征聚类效果,并基于二维特征建立了预紧状态定量表征模型,引入目标状态聚类中心与接受域参量,用于实现楔形环连接结构预紧状态定量评估。通过试验验证了所提方法的有效性,该方法可为楔形环连接结构定量辨识提供新的技术途径和思路,具有一定工程应用价值。

松辽盆地北部深层火山岩气藏勘探开发关键技术

松辽盆地北部徐家围子断陷火山岩气藏是徐深气田的主力气藏,具有岩性多样、储层非均质性强的特点,面临气藏富集规律不清、优质储层预测难、气井产能和井控储量变化规律复杂、剩余气挖潜难度大等一系列技术难点和挑战。通过开展火山岩气藏成藏演化过程分析、火山岩喷发期次描述、有效储层预测、井控储量评价、剩余潜力描述等工作,攻关形成了火山岩气藏成藏评价、三级火山体精细刻画、动态储量评价、剩余潜力评价及挖潜等技术。建立了“低渗增长型+高渗稳定型”2类动态储量模式及动静结合“六参数”挖潜技术政策界限,落实了烃源岩生气期及气藏成藏期,明确了气藏富集受源岩、断裂、储层、盖层四因素的联合控制,实现了对火山岩储层内部结构的精细表征,搞清了2类气井动态储量增长规律,形成了不同类型剩余气的挖潜技术对策。基于火山岩气藏一系列勘探开发关键技术的创新,徐深气田的天然气产量逐年攀升,形成的系列技术在大庆油田已得到全面推广应用,并取得了明显效果,有效支撑了大庆油田天然气产量的持续稳定增长。研究成果可为同类型气藏的勘探开发提供有效的技术指导。

虚拟仿真技术在材料分析与表征类课程实验教学中的应用

材料分析与表征类课程实验在巩固专业知识、提高学生实践创新能力方面不可替代。但由于设备数量、师资、学时等诸多方面的不足,导致材料分析与表征类课程实验以演示性实验为主,不利于锻炼学生的动手能力。结合材料分析与表征类课程实验的实践经验,针对实验中存在的问题,将虚拟仿真技术应用于实验教学中,形成一种“虚实结合”的实验模式,从而提高实验教学质量。

锂硫电池电解液多功能添加剂:作用机制及先进表征

锂硫电池作为一种新型清洁能源存储转化装置具有高理论比容量、环境友好等优点,是现如今储能领域中的重点研究对象。但电池充放电时氧化还原反应动力学缓慢及长链多硫化锂的穿梭效应影响电池循环寿命。电解液是锂硫电池的重要组成部分,在充放电过程中肩负着离子转移和电子传递的作用。近年来,锂硫电池多功能电解液添加剂的研究脱颖而出,在电解液中引入添加剂可实现催化多硫化锂转化反应、保护金属锂、调控界面等功能。本文通过对近期相关文献的探讨,综述了利用电解液添加剂提升电池充放电反应动力学和抑制多硫化物穿梭效应的策略,着重介绍了无机共盐、有机含硫、有机含氟、有机含硒/碲添加剂,重点分析了上述添加剂对多硫化物调控的作用机制。在探究电池内部的反应机理方面,介绍了多种具有实时性和精准性的原位表征仪器在锂硫电池中的应用。综合分析了锂硫电池电解液多功能添加剂的研究进展,针对多种类型添加剂的作用机制进行讨论;指出原位表征技术对揭示催化机理和设计功能添加剂的指导作用,并对锂硫电池电解液添加剂未来发展方向进行展望。

水环境溶解性有机质溯源与表征技术研究进展

水体中的溶解性有机质(DOM)来源广泛,成分复杂,可参与水中重金属迁移转化和生物地球化学循环过程,采用相应技术手段识别水体DOM来源,实现对DOM组分和性质的表征,对理解其生态环境效应具有指示意义。简要介绍了水环境中DOM的组成、特点及当前的研究热点,重点总结归纳了紫外-可见吸收光谱、三维荧光光谱、稳定同位素、生物标志物以及傅里叶变换离子回旋共振质谱等技术方法在水环境DOM溯源与表征中的应用特点、重要表征参数、影响因素和使用局限性。结果表明:紫外-可见吸收光谱和三维荧光光谱均有操作便捷、分析速度快、不破坏样品等优点,但二者对DOM表征的侧重点不同;稳定同位素技术重点关注DOM中的碳、氮等元素同位素组成及含量,生物标志物可记录DOM分子结构的信息,而傅里叶变换离子回旋共振质谱则是从分子级别对DOM进行表征。以上各技术对DOM的研究均有广阔的应用前景,但是由于DOM成分和组成元素的复杂性以及每种技术本身的局限性,多种技术的联合使用已成为水体DOM表征与解析的发展趋势。在此基础上阐述了多技术联用条件、目标和优点,归纳了现有研究中基于多技术联用的水环境DOM研究进展及研究案例,最后展望了DOM溯源与表征的未来发展方向。

栝楼籽多糖的提取工艺、初级结构及降血糖活性

为探究栝楼籽多糖的提取工艺、初级结构及降血糖活性,采用热水浸提法对栝楼籽多糖进行提取,经葡聚糖凝胶G-150纯化得到均质多糖(WHP-Ⅰ)后进行了初步表征。通过体外和体内联合法测试了栝楼籽多糖的降血糖活性。得到栝楼籽多糖的最优提取条件为提取温度80℃、提取时间100 min、料液比1∶25 (g∶m L)、浸提1次,在上述条件下,WHP-Ⅰ平均提取率为19.01%。WHP-Ⅰ的重均相对分子质量为4.765×10~4,并含有5种糖残基,WHP-Ⅰ表面较为平整,有孔状结构,且附着有细小的颗粒。WHP-Ⅰ对α-葡萄糖苷酶的半抑制浓度(IC_(50))为15.837 g/L,WHP-Ⅰ具有减缓Ⅱ型糖尿病(T2DM)引起脏器损伤的潜力,给药4周后,中剂量组M-WHP-Ⅰ[200 mg/(kg·bw)]和高剂量组H-WHP-Ⅰ[300 mg/(kg·bw)]小鼠的血糖值分别降低了32.13%和42.27%,且WHP-Ⅰ对糖尿病小鼠的肾脏和肝脏具有修复作用。

中国石油精细油藏描述技术新进展与展望

精细油藏描述研究是油田开发基础工作之一,其研究精度的不断提高,极大地促进了油田开发水平的提升。“十二五”和“十三五”期间,中国石油精细油藏描述研究针对多层砂岩油藏、复杂断块油藏、低渗透砂岩油藏、砾岩油藏、稠油油藏、特殊岩性油藏分别开展了技术攻关,形成了不同类型油藏配套技术系列。为了支撑剩余经济可采储量(SEC)储采平衡、老油田“压舱石”、采收率再提高、页岩油革命等“四大工程”,系统梳理中国石油精细油藏描述研究在5个方面的最新进展,分别是井震结合构造精细解释技术实现低级序断层定量描述,基于储层构型研究的单砂体刻画技术实现米级砂体描述预测,室内实验、数字岩心、物理模拟和数值模拟等方法技术实现综合剩余油表征,精细油藏描述成果平台建设实现研究过程协同共享和成果规范化存储管理,建章立制制定系列标准规范实现精细油藏描述研究规范化。通过系统总结精细油藏描述存在的8个方面问题,提出精细油藏描述的发展方向。

原位表征技术在锂硫电池机理研究中的应用

商用锂离子电池的低能量密度已经无法满足电动汽车和电子设备迅速发展的需求,锂硫电池作为一种高能量密度、绿色环保且成本低廉的储能器件,已经成为储能领域的重要议题。然而,氧化还原动力学缓慢、穿梭效应严重、电解液耗竭以及锂负极的降解等问题依然阻碍着锂硫电池商业化的脚步。研究锂硫电池系统内各部件的基本反应机制对于解决以上问题,并进一步提高电池的整体性能至关重要。原位表征技术可用于锂硫电池充放电过程中各部件结构变化与反应进程的实时观察与研究,对锂硫电池机理的揭示有望从材料设计层面大幅提升电池整体性能。本文通过对近期研究工作进行总结,介绍了锂硫电池在提高循环寿命和高能量密度上遇到的瓶颈性问题,简述了原位拉曼光谱、原位透射电镜、原位共振非弹性X射线散射、原位红外光谱和原位核磁共振光谱等原位表征技术在锂硫电池中的应用。并结合锂硫电池涉及的氧化还原反应、多硫化物溶解、电解液对多硫化物的抑制以及锂负极降解等具体环节,重点分析了原位表征技术在这些具体环节中监测多硫化物转化过程和探究锂硫电池内部反应机理方面的研究进展,指出了原位表征技术在促进锂硫电池机理理解方面的重要作用。