Physical and mechanical characteristics of composite briquette from coal and pretreated wood fines

Melina wood torrefied at 260℃ for 60 min was agglomerated with lean grade coal fines into composite briquettes using pitch as binder.Torrefied biomass(3%-20%)and coal fines(80%-97%)were blended together to produce the composite briquettes under a hydraulic press(28 MPa).The briquettes were cured at 300℃.Density,water resistance,drop to fracture,impact resistance,and cold crushing strength were evaluated for the composite briquettes.The proximate,ultimate,and calorific value analyses were carried out according to different ASTM standards.Microstructural studies were carried out using scanning electron microscope and electron probe microanalyzer equipped with energy dispersive x-ray.Fourier Transform Infrared Spectrophotometer(FTIR)was used to obtain the functional groups in the raw materials and briquettes.The density of the composite briquettes ranged from 0.92 to 1.31 g/cm^(3) after curing.Briquettes with<10%torrefied biomass has good water resistance index(>95%).The highest cold crushing strength of 4 MPa was obtained for briquettes produced from 97%coal fines and 3%torrefied biomass.The highest drop to fracture(54 times/2 m)and impact resistance index(1350)were obtained for the sample produced from 97%coal and 3%torrefied biomass.The fixed and elemental carbons of the briquettes showed a mild improvement compared to the raw coal.The peaks from FTIR spectra for the briquettes shows the presence of aromatic C=C bonds and phenolic OH group.The composite briquettes with up to 20%torrefied biomass can all be useful as fuel for various applications.

Design Strategies for Leaning-Type Arch Bridges

This paper presents a study on the design strategy of leaning-type arch bridges.The main characteristics of leaning-type arch bridges are first introduced;Kunshan Yufeng Bridge is taken as an example to discuss different aspects of a design strategy,which includes self-system optimization,selection of beam length and bridge deck position,and other aspects.This paper can be used as a reference to further improve and develop bridge design.

Investigating the effect of blade sweep and lean in one stage of an industrial gas turbine's transonic compressor

In this paper,the simultaneous effects of the sweep and lean of the blades in one stage of a transonic compressor on its performance have been investigated.Then,with the help of numerical solution,fluid flows over these two modified geometries generated from the original sample were analyzed.Considering the applied constraints,the two generated rotor geometries have different geometrical characteristics;so that in rotor No.1,the blade has a backward sweep and it is less affected by lean,while in the modified rotor No.2,the blade has a forward sweep and it is more affected by lean.In the first sample,it is observed that the stage efficiency increases by 0.5%for operating design,while the stall margin reduces,and the chocking mass flow rate diminishes by 1.5%.Also regarding the second modified blade,the results indicate that the stall margin increases,the choking flow rate at the nominal rotational speed of the stage increases by 0.18%and the stage efficiency increases by 1%.The comparison of numerical results also shows that,in the first modified rotor,the pressure ratio of the stage diminishes by 0.01%;while in the second sample,the pressure ratio of the stage increases by the same amount.These results were then compared with the experimental results,showing a good agreement.

初始训练水平男性青年学员体成分与最大摄氧量之间的关系研究

目的:研究初始训练水平男性青年学员体成分与最大摄氧量之间的关系,为日常训练提供依据。方法:26名健康男性受试者进行为期6个月的军事基础体能训练,采用双能X射线骨密度仪进行体成分检测,并进行最大摄氧量测试。结果:瘦体重、瘦体重指数(Lean/Height2)、下肢瘦体重与最大摄氧量不存在相关性,而上肢瘦体重(r=-0.44,P<0.05)、上肢瘦体重/下肢瘦体重(r=-0.41,P<0.05)与最大摄氧量之间存在相关关系,全身脂肪百分比平均值表现为:肥胖质量/体重、躯干脂肪比/腿部脂肪比、躯干/四肢脂肪质量及骨密度与最大摄氧量不存在相关关系(P>0.05)。结论:对于初始训练水平的人员,上肢瘦体重的增加可能不利于最大摄氧量的提高,潜在影响耐力运动的表现。

Applications of numerical optimization techniques to design of axial compressor blades

This paper describes the shape optimization of NASA rotor 37 and rotor and stator blades in a single-stage transonic axial compressor.Shape optimization of the blades operating at the design flow condition has been performed using the response surface method and three-dimensional Navier-Stokes analysis.Thin-layer approximation is introduced to the Navier-Stokes equations,and an explicit Runge-Kutta scheme is used to solve the governing equations.The three design variables,blade sweep,lean and skew,are introduced to optimize the three-dimensional stacking line of the blades.The objective function of the shape optimization is an adiabatic efficiency.Throughout the optimization of rotor and stator blades, optimal blade shape can be obtained.It is noted the increase of adiabatic efficiency by optimization of the blade shape with the stacking line in the single-stage transonic axial compressor is more effective in a rotor blade rather than a stator blade because of the large deformation of blade shape in the stator blade.

Enrichment factors and sweep spot evaluation of Jurassic tight oil in central Sichuan Basin,SW China

The secondary migration mechanism,enrichment factors of Jurassic tight oil in central Sichuan Basin were well investigated through physical simulation experiment of reservoir formation,casting and fluorescent thin sections,field emission scanning electron microscope(FESEM)and environment scanning electron microscope(ESEM).The results show that migration of Jurassic tight oil in central Sichuan Basin is a low-velocity non-Darcy flow through low-efficient migration path under the huge migration driving force,and has three migration and seepage stages,i.e.viscous flow stage,nonlinear seepage stage,and quasi-liner seepage stage.Microscopically,the migration pathway of tight oil is the porefracture composite conduction;macroscopically,the migration mode of tight oil is the large-scale shortedistance migration.Distribution of favorable zones of tight oil is controlled by distribution of high-quality source rocks.The hydrocarbon-generation strength of 0.4
106 t/km2 can be as a threshold to determine favorable zone of tight oil in the study area.The reservoirs with high permeability and high porosity can form tight oil sweet spots,and the development degree of fractures is closely related to well with high yield of tight oil well.

基于共光路中快反镜的复合轴控制和回扫补偿技术分析

随着长焦共光路成像组件广泛应用于光电侦察吊舱,长焦共光路光路中快反镜在复合轴稳像等方面的技术开发成为必然的趋势。文章介绍了长焦共光路成像组件的主要组成,基于快反镜实现复合轴控制与回扫补偿控制的策略,其工作时序和关键参数分析计算。开发了基于长焦共光路成像组件的快反镜,一帧图像时间内同时实现二次稳像和回扫补偿的功能。提升了中高空光电侦察吊舱的侦察作用距离、稳像精度和搜索效率。

掺超贫铁矿石混凝土力学性能及微观结构研究

这是一篇陶瓷及复合材料领域的论文。对超贫铁矿石进行加工处理,将良好级配的超贫铁矿石作为骨料,制备新型的蒸压加气混凝土砌块,进而研究不同骨料的掺量、水灰比和蒸压时间对蒸压加气混凝土性能以及微观结构的影响。结果表明:随着水灰比,石灰掺量、骨料取代率和蒸压时间的增大,混凝土的抗压强度均呈现先增大、后减小的趋势;超贫铁矿石骨料的取代率为40%,粉煤灰掺量为10%、石灰掺量为18%、水泥掺量为60%,水灰比为0.45和蒸压时间为5 h时,混凝土的性能达到较佳。同时,超贫铁矿石的掺入对新物相的产生和混凝土自身以及孔隙结构具有较大的影响。

长白猪胴体组成与瘦肉率的关系

选择杭州市种猪试验场长白猪第 8个世代的 34头猪进行肥育与屠宰试验。结果表明 ,瘦肉率与肩胸块率和腿臀块率有呈正相关的趋势 (P >0 0 5 ) ,而与颈块率和腰腹块率有呈负相关的趋势 (P >0 0 5 ) ;而且腿臀块与肩胸块的肉率最高 ,其与瘦肉率的相关也最大。说明适当选留肩胸部和腿臀部较发达的猪 ,有利于提高猪群的瘦肉率。瘦肉率与皮脂率和背腰处膘厚呈很强的负相关 (P <0 0 1) ,而与胴体长和眼肌面积呈正相关 (P <0 0 5 )。说明只需对胴体进行皮脂剥离和进行有关测量 ,即可较为准确地推断出长白猪的胴体瘦肉率。

健美操教学对改变女大学生身体素质及体成分的探讨

通过对 17- 2 0岁参加健美操体育教学课的 16 5名女大学生进行健美操体育教学课前后两次身体素质及体质测试 ,结果表明 :经过一学期 18周 36学时的健美操体育教学课 ,受试者弹跳力、腰腹肌、上肢力量、速度。

超大体积混凝土温度裂缝产生机理分析与抗裂控制新对策

介绍了超大体积混凝土的概念;阐述了超大体积混凝土温度裂缝产生的两个必要条件是温差和约束;指出超大体积混凝土在水泥水化升温的初期,混凝土容易出现内高外低的温差,在内约束作用下,形成表面裂缝;在超大体积混凝土降温阶段,由于混凝土的收缩,在外约束作用下,容易导致贯穿裂缝。贯穿裂缝会严重影响结构的性能,它会破坏结构的整体性、耐久性等。根据"抗放兼施"的原则,提出了两种实用的抗裂新对策:运用"复合式的超大体积贫混凝土"和运用"有弹性的滑动式垫层",并介绍这两种对策在工程中的具体做法。这两种方法对超大体积混凝土抗裂问题具有一定的指导意义。

人体瘦组织对骨密度的影响

目的探讨人体瘦组织对骨密度的影响。方法将160例进行DXA(Dual-energy x-ray absorptiometry双能X线骨密度吸收仪)骨密度和身体成分分析的患者作为研究对象,根据瘦组织指数将女性和男性患者平分为高瘦组织指数组和低瘦组织指数组,比较二组的股骨颈、全髋和腰椎骨密度。结果 54例高瘦组织指数组女性瘦组织指数为16.9942±1.2634 kg/m^2,54例低瘦组织指数组女性瘦组织指数为14.2981±0.7956 kg/m^2;26例高瘦组织指数组男性瘦组织指数为19.5200±1.0863 kg/m^2,26例低瘦组织指数组男性瘦组织指数为16.0654±1.4077 kg/m^2。男女高瘦组织指数组的股骨颈、全髋和腰椎骨密度均显著高于低瘦组织指数组(P<0.05)。结论高瘦组织指数女性和男性患者均具有较高的股骨颈、全髋和腰椎骨密度。

中心复合实验优化竹黄半纤维素水解的工艺研究

以戊糖收率和水解底物失重率为评价指标,采用中心复合实验设计法对酸性亚硫酸氢钠(ASB)预水解竹黄制备戊糖工艺进行了优化。研究结果表明,各因素对戊糖收率的影响显著性顺序为硫酸质量浓度(X3)>亚硫酸氢钠质量浓度(X4)>反应时间(X2)>反应温度(X1);对水解底物失重率的影响显著性顺序为反应温度(X1)>硫酸质量浓度(X3)>反应时间(X2)>亚硫酸氢钠质量浓度(X4)。当固液比(W/V)为1∶5时,ASB预水解最佳工艺条件为:水解温度为171.1℃,水解时间为37 min,硫酸质量浓度为13.92 g/L,亚硫酸氢钠质量浓度为13.84 g/L,在此条件下得到的戊糖收率为83.93%,底物失重率为29.36%。通过验证实验表明,该设计模型具有良好预测性。

利用宽带音频扫描加载实现复合材料结构质量检测的数字散斑错位术研究

本文系统地分析了数字散斑错位术相关条纹的形成机理,并结合此项技术提出一种新的加载方式宽带音频扫描加载,同时从理论上剖析了该加载方式的可行性,从而构造出一种新的无损测试系统.采用该检测系统对带有预制不同形状和尺寸缺陷的复合材料模型进行检测验证,发现该技术使用方便,检测时不受环境的影响,可以实现现场在线原位实时检测,并能够得到非常真实的检测结果,从而可以实现更为精确的定量计算.

三种静气动弹性发散方法的一致性分析和验证

介绍了 3种静气弹发散方法 (柔度法、模态法、颤振法 ) ,并对这 3种方法的一致性从理论上进行了分析和证明。使用这 3种方法对 5个平板机翼模型的发散速度进行了计算 ,其实际发散速度也从低速风洞试验中获得。通过对比计算结果和各模型风洞试验结果 ,进一步验证了这 3种方法的一致性。另外 ,还提出了在模态法和颤振法中基于发散特征向量的结构模态选取原则。

绝经后女性体成分与骨强度的相关性研究

目的探讨绝经后女性瘦组织(LM)、体脂量(FM)对骨强度的影响。方法 101例健康女性受试者(年龄61.3±7.1岁)行腰椎、髋部及全身双能X线吸收测量法扫描获取腰椎(LS_BMD)、股骨颈(FN_BMD)、全髋(TH_BMD)、全身骨密度(TB_BMD)及全身骨矿物质含量(TB_BMC)。结果年龄、绝经年龄、身高、体重与TB_BMD、TB_BMC、LS_BMD、FN_BMD、TH_BMD存在线性相关性,P均<0.05。LM及FM与TB_BMD、TB_BMC、LS_BMD、FN_BMD、TH_BMD存在轻～中度正相关性(r=0.219～0.580,P均<0.05)。逐步多元线性回归分析,校正FM则LM对上述骨强度指标的影响消失,只有FM进入回归模型,FM解释TB_BMD、TB_BMC、LS_BMD、FN_BMD及TH_BMD变量变化分别为26.1%、60.9%、13.1%、19.9%、16.1%。结论是FM而非LM决定绝经后女性骨强度。

《复合材料》课程建设与教学研究

《复合材料》课程是为进一步拓宽学生的专业知识而开设的一门专业课,根据复合材料专业课程的特点,提出教学内容应具有个性化、信息化、长期化;教师应充分利用现代教育技术手段,采用互动式教学方法,加强学生专业技能训练,培养学生独立思考能力和创新能力;考核形式多元化,有利于培养学生综合能力。

军队院校毕业班学员的人体成分检测

目的：通过测量军校毕业学员的人体成分,探讨军校毕业学员与普通居民的区别,并为建立相关标准提供依据。方法：按飞行院校、分流院校、合训院校、技术院校和士官学校分层抽取5968名毕业学员,分别进行人体成分检测,根据结果划定5%-95%分布上下限。并就军校毕业学员的体脂百分比、体质指数（BMI）、肌肉百分比、骨质百分比指标与同年龄、同性别城乡居民进行比较。结果：1军队院校毕业学员体脂百分比的参考值范围为10.3%-20.7%（男）和19.2%-30.1%（女）;BMI参考值范围为19.30-25.70（男）和18.00-23.99（女）;瘦体重百分比参考值范围为79.3%-86.7%（男）和69.9%-80.7%（女）;肌肉百分比参考值范围为74.2%-84.0%（男）和65.2%-75.3%（女）;骨质百分比参考值范围为5.0%-5.8%（男）和4.7%-5.5%（女）。2与同年龄、同性别城乡居民比较,军队院校毕业学员的体脂百分比明显较少,肌肉百分比、骨质百分比明显较高。结论：1军队院校毕业学员的身体成分数据明显优于同年龄、同性别城乡居民,总体表现为体脂较少,肌肉和骨质较多。2军队院校毕业学员的体质状况不能简单采用民用标准,需建立一套符合军校毕业学员的标准。

《功能复合材料》互动式教学模式的构建与实践

文章分析了在《功能复合材料》课程中开展互动式教学的可行性;介绍了该课程互动式教学模式的构建,以及在教学方法、教学内容和考核评价方式等方面的实践经验。

超重及肥胖青少年骨密度、骨矿含量与脂肪和去脂软组织质量关系的研究

目的:探讨超重及肥胖青少年骨密度、骨矿含量与脂肪和去脂软组织质量的关系。方法:身体健康的超重或肥胖青少年50人,以双能X射线吸收法,采用全身扫描模式,测量全身及各区域骨密度、骨矿含量、脂肪质量和去脂软组织质量。以多元逐步线性回归分析体重、BMI、体脂百分比、全身脂肪质量和去脂软组织质量与骨密度、骨矿含量的关系。结果:(1)全身、腿部和骨盆骨密度、骨矿含量与体重、BMI和全身去脂软组织质量呈显著正相关。(2)体重、全身去脂软组织质量与全身骨密度和骨盆骨密度间呈中等相关(P<0.01),与腿部骨密度呈强相关(P<0.001);体脂百分比与全身、腿部和骨盆骨密度均呈显著负相关,其中与腿部骨密度呈中等负相关(P<0.01)。(3)全身去脂软组织质量与全身和骨盆骨矿含量呈强相关性(P<0.001),与腿部骨矿含量呈极强相关性(P<0.001)。全身、腿部和骨盆骨矿含量与体脂百分比呈显著负相关(P<0.05)。(4)多元逐步线性回归分析结果显示全身去脂软组织质量是影响超重和肥胖青少年全身、腿部以及骨盆骨密度和骨矿含量的决定性变量,腿部骨密度的52.6%、腿部骨矿含量的73.1%由全身去脂软组织质量决定。结论:超重及肥胖青少年体重、BMI和全身去脂软组织质量与骨密度、骨矿含量呈显著正相关,体脂百分比与骨密度、骨矿含量均呈显著负相关。其中,全身去脂软组织质量是影响骨密度、骨矿含量的决定性因素。