瓦楞纸板成型与瓦楞辊齿顶的动态包角方程

目的研究瓦楞辊齿顶动态包角变化规律,优化瓦楞辊的楞型参数。方法建立瓦楞纸板成型过程中瓦楞辊的齿顶动态包角方程,选取3组实际楞型参数,对每一个不同的转动角度所对应的动态包角进行计算,并用Matlab求解,以确定在一个啮合周期内包角的变化规律及其影响参数。结果不同楞型参数瓦楞辊在工作时的总包角变化规律不同,且该变化规律与实测工况一致;瓦楞辊齿顶动态总包角的突变会导致瓦楞纸成型过程的振动和噪声明显增大,从而降低成型质量、减短机器寿命。结论建立的动态总包角方程符合瓦楞纸板的实际成型过程,为瓦楞辊的优化设计及误差分析奠定了理论基础。     

温湿度对瓦楞原纸弹性模量影响的研究

试验研究了温湿度条件对瓦楞原纸含水率的影响,以及瓦楞原纸含水率对其弹性模量的影响,构建了含水率与温湿度的三维关系图。试验结果表明:瓦楞原纸的含水率既受相对湿度的影响,又受温度的影响,温度对瓦楞原纸弹性模量的影响比相对湿度的影响小;瓦楞原纸含水率随温度的上升而下降,随相对湿度的上升而上升;瓦楞原纸弹性模量随含水率的上升而下降。     

单面瓦楞机高速瓦楞辊齿形参数的优化设计

以瓦楞辊的运动学性能参数为目标函数,以齿形参数（ｒ１,ｒ２,Ｒ１,Ｒ２）设计变量,以ＭＡＴＬＡＢ语言工具箱为工具进行优化,得出在满足原纸最大张力、进纸速度、折楞率、齿形角、楞高等约束条件下的最优齿形参数。此结果对进一步研究瓦楞机的运动特性,优化工作性能提供了依据。     

瓦楞脆裂与塌扁的技术问题

芬兰纸板协会技术人员在沪参观我瓦楞纸箱生产工艺过程中,就我方存在的瓦楞成品容易发生脆裂与塌扁问题提出看法如下:一、瓦楞的变脆、破碎由於我瓦楞原纸系切成单片,并且堆放了一些时候,原纸失去其正常湿度而变脆。因此瓦楞原纸必须在切好后马上就轧成瓦楞,或者在半自动单机加工前,用湿热蒸气预热。     

合理选用瓦楞原纸和箱纸板提高瓦楞纸箱质量

瓦楞纸箱要具备良好的保护功能,就必须具有一定的牢固度和耐用性,而瓦楞纸箱是由瓦楞纸板加工而成,瓦楞纸板是由箱纸板和瓦楞芯纸黏合而成,瓦楞芯纸又是由瓦楞原纸轧制而成,因此,瓦楞纸箱的各项性能受到瓦楞原纸、箱纸板质量和性能的影响。本文简单介绍瓦楞原纸、箱纸板的性能指标及储存和选用的一些基本原则。     

合理选用瓦楞原纸和箱纸板提高瓦楞纸箱质量

瓦楞纸箱要具备良好的保护功能,就必须具有一定的牢固度和耐用性,而瓦楞纸箱是由瓦楞纸板加工而成,瓦楞纸板是由箱纸板和瓦楞芯纸黏合而成,瓦楞芯纸又是由瓦楞原纸轧制而成,因此,瓦楞纸箱的各项性能受到瓦楞原纸、箱纸板质量和性能的影响。本文简单介绍瓦楞原纸、箱纸板的性能指标及储存和选用的一些基本原则。     

瓦楞辊齿形参数对瓦楞原纸用量的影响

一、引言瓦楞辊齿形设计是一个很复杂的问题。在设计时,需要考虑的因素很多,如齿形对瓦楞纸板强度的影响,齿形对瓦楞辊寿命的影响,齿形对瓦楞辊的振动噪音的影响等等。但设计人员往往忽视齿形对瓦楞原纸用量的影响。由于瓦楞纸板的年产量很高,齿形参数变化虽然很小,而瓦楞原纸的使用量却会变化很大。这对于企业的经济效益有直接的影响。因此,在设计瓦楞辊齿形时,必须全面考虑问题,除了考虑齿形对纸板强度等方面的因素外.还要考虑纸板生产企业的经济效益。     

我国瓦楞原纸需求将大幅增加

据资料介绍 ,从全球范围统计 ,瓦楞材料消费约占全部纸和纸板消费的 1 / 3。根据专家预测 ,2 0 0 5年我国纸和纸板消费约 50 0 0万吨 ,瓦楞材料消费如按 30 %测算 ,届时我国瓦楞材料消费量为1 50 0万吨。从宏观统计来看 ,各国(地区 )瓦楞纸板中箱板和瓦楞原纸所占比例不同 :美国瓦楞原纸 31 .5 % ;日本占 39% ;韩国占 30 % ;英国占 38% ;中国台湾占 41 % ,这和该地区所用瓦楞板结构及瓦楞原纸的定量有关。我国瓦楞原纸消费比重比箱板纸高得多 ,1 998年瓦楞纸板消费量为 956万吨 ,其中瓦楞原料纸 586万吨 ,占 61 %这种比例正和国际上的比例相…     

瓦楞原纸环压强度测量不确定度评定

目的为提高瓦楞原纸的检测水平,研究瓦楞原纸环压强度测量的不确定度评定方法。方法根据JJF 1059.1—2012《测量不确定度评定与表示》,对瓦楞原纸进行抽样,分析其环压强度不确定的主要来源并对其量化,对检测结果进行评定。结果瓦楞原纸环压强度测量的扩展不确定度为78.78,置信概率为95%,包含因子为2。结论检测结果可用于瓦楞原纸环压强度的合格判断,对于其他性能如耐破度、戳穿强度的不确定评定具有参考价值。     

瑞典Bullerud公司推出低克重瓦楞包装原纸

瑞典Bullerud公司研制生产出定量为99 g／m2的 低克重瓦楞原纸。该公司表示,这一产品特点适合于 包装食品,如比萨和其他外卖食品。 据介绍,这种包装原纸是采用100％的斯堪的纳 维亚桦木原生纤维的半化学浆而生产的瓦楞原纸。     

利用"球面三角"建立三维图形旋转变换参数间的关系

三维图形的旋转变换可以使用不同的方法进行描述，但都是由3个独立的参数确定的。为了从多个角度使用不同的手段研究旋转变换问题，本文提供了一种非常直观、简捷的计算方法，即利用“球面三角”的方法建立了用欧拉角与用方向余弦描述三维图形旋转变换的转换关系。     

Toward the extraction of single species of single-walled carbon nanotubes using fluorene-based polymers

High purity of (7,5) SWNTs (approximately 79% of the semisonducting SWNT ensemble) can be obtained by polymer-assisted extraction from the narrow-diameter distributed SWNTs produced by the catalyst Co-MCM-41. The fluorene-based polymers are able to selectively wrap the single-walled carbon nanotubes (SWNTs) with certain chiral angles or diameters depending on their chemical structures. Poly(9,9-dioctyfluoreny1-2, 7-diyl) and poly[(9,9-dihexylfluorenyl-2,7-diyl)-co-(9,10-anthracene)] selectively wrap SWNTs with high chiral angles (>24.5 degrees). By contrast, poly[9,9-dioctylfluorenyl-2,7-diyl)-co-1,4-benzo-{2,1'-3}-thiadiazole)] preferentially wraps the SWNTs with certain diameter (1.02-1.06 nm).     

对称圆弧加直线修正型线涡旋压缩机脱啮角与排气角研究

在采用对称圆弧加直线修正型线涡旋压缩机设计计算中,形成中心压缩腔时的转角与压缩机排气时主轴的转角完全不同.针对这两种情形下的主轴转角,由于没有完整而清晰的阐述,导致计算涡旋压缩机各压缩腔容积时容易产生较大误差.对此,通过研究采用对称圆弧加直线修正涡旋压缩机涡盘始端型线的几何特性,定义了脱啮角与实际排气角,阐明了二者之间相互区别,详细推导了脱啮角计算公式并分析了影响脱啮角的因素,且根据涡盘始端壁厚增加造成修正后中心压缩腔容积减少的本质特点,提供了修正后涡盘始端壁厚增加容积和实际排气角的计算方法.通过运算实例验证了脱啮角与实际排气角相差很大的结论,指出实际排气角将影响排气孔的设计.     

盘式自动折叠纸盒结构设计

重新定义盘式折叠纸盒,简介两种典型结构,给出了内外折叠角的求解公式,使传统纸盒从长方体模式向多样化发展。     

On the bending of a stretched wire - case study of a tension measuring device

The case of a stretched wire bent successively over a system of three pulleys has been analysed with specific reference to a commonly used wire tension measuring device. With the help of the simple theory of elastic bending, expressions for the tension variation, angles of wrap, deflections etc., at the pulley have been obtained. A brief parametric study leads to some useful design guidelines. The analysis can be usefully applied to other systems also where wirelwire rope is bent over multiple pulleys.     

无衍射光电子标靶及误差分析

提出了一种新型的用于盾构机导向的无衍射光电子标靶,利用映射关系将全站仪激光入射到标靶中CCD上的光斑场盾中心位置和全站仪的角度值联系起来,结合电子水平仪读数,得到标靶的完整姿态角,并计算盾首中心坐标.分析测量过程中全站仪,标靶各部件引起的误差,推导标靶测量姿态角及盾首中心坐标的误差.分析表明,标靶测量盾首的偏差精度达到...     

Preparation of defined bulk densities for using the capillary rise method in the case of fine powders

The wetting properties of powders are important in many technological processes. Contact angles can be characterized by an effective contact angle of the particle arrangement relative to the wetting liquid, but their quantification is problematic. An exact determination depends on an accurate preparation of the test samples. A defined pre-consolidation by vertical shocks is introduced in this paper.     

The relation between the distribution of dihedral angles and the wetting angle during liquid phase sintering

This study presents a Monte Carlo method to simulate the effect of the wetting angle on a dihedral angle distribution and on a degree of the grain boundary penetration of a liquid phase during liquid phase sintering. For the high probability for wetting, the number of the grain boundary penetration of a liquid phase increased while the wetting angle decreased and a few bonded grains maintained a stable grain boundary with high dihedral angles. This finding contradicts the classical prediction that smaller values of mean dihedral angles produce superior wettability.     

The relation between compressive strength of carbon/epoxy fabrics and micro-tow geometry with various bias angles

In this paper compressive tests of carbon/epoxy (plain weave, 3k) fabric composites were performed to investigate the relation between compressive strength and various bias angles and shear angles. Compressive properties such as chord modulus and maximum strength of the fabric composite materials are essential to analyze the drape behaviour and estimate the quality of the final products. Various specimens with different bias and shear angles which were fabricated by using autoclave de-gassing moulding process were prepared to estimate the strength and chord modulus with respect to the bias and shear angle variations. The stacking sequences of the compressive test specimens are [0]_10T, [15]_10T, [30]_10T and [45]_10T for bias specimens and [±37]_10T, [±32]_10T, [±28]_10T, [±22]_10T for sheared specimens. Micro-tow structures were observed to correlate the fabric compressive strength with crimp angle. Anti-buckling rig was involved to prevent specimens from buckling during the compressive tests. The compressive test was performed with 1.3 mm/min strain rates. Compressive test results were compared with calculation results. Facture modes which were classified in two different modes were analyzed using microscopic observation.