Study on Pneumatic Splice

An ideal pneumatic splice has not only interminglings in the middle, but also many small wrappings on both sides of the spliced region, and must have near overlapping loopy wrappings at both ends. Only the fluffy and hairy untwisted yarn ends obtained from a swirling jet untwisting can generate many small wrappings when spliced.To get the fluffy and hairy untwisted yarn ends, a small swirling intensity value X must be used to eliminate a reverse flow zone. To increase the wrappings at both ends, a larger swirling intensity value X must be used to form a reverse flow zone. Only a perfect splice can better the yarn's appearance,increase its strength and make it impossible for its fibers to slip easily.     

玻璃纤维长丝纱机械性能的研究

本文对玻璃纤维长丝纱的机械性能做了较全面的讨论。文中着重探讨了玻璃纤维长丝纱在静负荷作用下的松驰性能以及反复循环负荷作用下的疲劳性能,同时设计了测定玻璃纤维长丝纱弯曲性能的试验方法——套环法,并提出了相应的指标——抗弯系数W。试验结果表明,玻璃纤维长丝纱有较明显的应力松驰现象,反复循环负荷作用对玻璃纤维长丝纱的强伸性能有较大的影响。     

Spliced leader RNAs from lower eukaryotes are trans-spliced in mammalian cells.

Exon sequences present on separate RNA molecules can be joined by trans-splicing in trypanosomatids, Euglena, and in the nematode and trematode worms. Trans-splicing involves an interaction between a 5' splice site present in a spliced leader RNA and a 3' splice site located near the 5' end of pre-messenger RNAs. In vitro trans-splicing of artificial mammalian pre-mRNAs has been reported, but the efficiency of splicing appears to depend on sequence complementarity between the two substrates. There has been speculation that some natural pre-mRNAs can be trans-spliced in mammalian cells in vivo, but alternative interpretations have not been ruled out. Here we show that spliced leader RNAs can be accurately trans-spliced in mammalian cells in vivo and in vitro. Both nematode and mammalian 3' splice sites can function as acceptors for trans-splicing in vivo. These results reveal functional conservation in the splicing machinery between lower eukaryotes and mammals, and they directly demonstrate the potential for trans-splicing in mammalian cells.     

Predicting the Tensile Curve of Polyester Twisted Ply Yarn under Large Deformation

Considering the changes of ply yarn 's structure parameters during the axial extension,a new model has been proposed for predicting the tensile curve of polyester twisted ply yarn under large deformation without the tensile strength tests.The relationships between the structural parameters and tensile properties under large deformation were considered.The feasibility and accuracy of the model were studied by comparing the predictive results and the experimental ones.The structural parameters in the model were acquired under every strain before rupture.The radial dimension and twist angle of the yarn were obtained by an observation platform and image processing technique.The true modulus of the yarn was obtained indirectly from the tensile data of the single yarn and the mathematical equations.The tensile curves of the yarns at different twist levels for predicting were plotted.The results demonstrated that the predicted curve tendency and the values were quite close to the experimental ones.The model exhibited a good applicability to predict the tensile curves for low and medium twist yarns.     

不同测试条件对羊毛／莱卡包芯纱拉伸性能的影响

通过正交试验，分析拉伸速度、夹持长度、纱线线密度TF等因素对羊毛／莱卡包芯纱拉伸性能的影响．实验结果表明，影响纱线拉伸断裂强度程度大小依次为纱线线密度、拉伸速度、夹持长度；同种线密度的羊毛／莱卡包芯纱，在相同拉伸速度的条件下，随着夹持长度的增大，羊毛／莱卡包芯纱的断裂强力减小；在相同拉伸速度的条件下，包芯纱的断裂伸长率随着夹持长度增大而减小．     

中华蜜蜂幼虫肠道响应球囊菌胁迫的可变剪切基因分析

基于前期已获得的中华蜜蜂(简称中蜂)幼虫肠道转录组数据,利用TopHat2软件在正常(AcCK)及球囊菌胁迫的中蜂幼虫肠道样品(AcT1、AcT2、AcT3)中共鉴定出发生于9124个基因的57327个可变剪切事件,其中以基因间(17.68%)、可变3′端剪切(15.32%)、外显子跨越(14.12%)和可变5′端剪切(12.81%)类型为主.Venn分析结果显示4个肠道样品的共有可变剪切基因数为8111个,特有可变剪切基因数分别为272、189和385个.GO分类结果显示共有可变剪切基因涉及47个条目,AcT1、AcT2、AcT3的特有可变剪切基因分别富集于24、20和34个条目.KEGG代谢通路富集分析结果显示,共有可变剪切基因富集在327个代谢通路,基因富集数最多的是RNA转运、内质网蛋白加工及核糖体;AcT1、AcT2、AcT3的特有可变剪切基因分别富集在22、46和83个代谢通路.结果揭示了可变剪切基因在宿主的胁迫响应过程中的重要作用.     

织造和染整加工前后精梳毛纱拉伸性能的关系

为了根据织造前纱线的拉伸性能和织造、后整理工艺预测织物的拉伸性能,研究了织造和染整加工前后精梳毛纱拉伸性能的关系,获得了三方面的结论:(1)经常规后整理加工的各种精梳毛织物中经纱的伸长变形能力没有显著差异,但其纬纱的伸长变形能力与织造和染整工艺有关。(2)坯布染色情况下织造前纱线的伸长变形曲线在伸长率方向扩大一定倍数以后与织物中纱线的伸长变形曲线相当。纱线染色情况下织造前纱线的伸长变形曲线的某一部分与织物中纱线的伸长变形曲线相当。(3)后整理加工中的经向张力和拉幅张力对精梳毛织物中纱线的伸长变形能力的影响特别大。树脂整理有降低织物变形特别是变形回复能力的作用。     

棉／维纶混纺纱及其针织产品性能分析

对棉/维纶混纺纱线及其针织物进行了退维工艺处理,从而获得相应纱线及其针织物.并对处理前后纱线的断裂强力、失重率、毛羽以及织物的压缩性能、保暖性和吸湿快干性进行了测试分析,得出该纱线具有良好的机械与服用性能.     

Simulation and Experimental Study of Dynamic Characteristics of a Pneumatic Actuator in Air Splicer

Splicing process parameters determined by dynamic characteristic of pneumatic actuator in air splicer have a significant influence on the performance of spliced yarn. Both gas thermodynamic and pneumatic actuator dynamic models, which were solved by the Runge-Kutta algorithm, were established to analyze the relationship among structural parameters of a pneumatic actuator and splicing process parameters such as splicing duration and gas consumption. Additionally,a visualization test bench to observe the dynamics of the pneumatic actuator and a mass flow measurement system to track splicing duration and gas consumption were designed. Comparisons between experimental data and simulation results show that the mathematical model accurately accounts for the dynamic characteristics of the pneumatic actuator,and consequently predicts splicing process parameters, which provides a theoretical foundation for the design optimization of air splicer.     

BP神经网络预测织物拉伸性能

采用BP神经网络技术建立反映织物结构参数、纱线参数与织物拉伸性能间关系的三层神经网络模型,根据影响织物拉伸性能的各种参主为量,用动量-学习率自适应调整的BP算法训练模型,通过预测值和实验值的比较,表明用神经网络方法预测织物拉伸性能有相当的准确性,从而在一定程度上实现用神经网络预测织物的拉伸性能。     

双组分纤维混纺纱强伸性能的研究

从双组分纤维纯纺纱的拉伸性能和断裂过程出发，对双组分纤维的混纺纱的断裂特性进行了分析，建立了双组分纤维混纺纱的伸长率与各组分纤维本身的拉伸性能，混纺比之间的理论关系式，并用几种双组分纤维及其混纺纱的实验拉伸结果与所推出的理论关系式做了验证对比，证明所建立的理论关系式是可靠的。该式对于预测混纺纱的拉伸性能，从而正确选择混纺纤维及其混纺比有理论指导意义。     

Tensile Property of Bi-axial Warp Knitted Structure

The tensile property of bi-axial warp knitted fabrics is tested and compared with that of the plain weave fabric. The results show that there are obvious differences between the tensile property of a bi-axial warp knitted fabric and that of a plain weave fabric. The former can give fuller play to the property of a high modulus yarn than the latter. The tensile strength of a bi-axial warp knitted fabric is linear with the number of yarns in the direction of force.     

压缩域MPEG-2视频流无缝拼接中的码率控制算法

为防止由视频流无缝拼接造成的解码缓冲器溢出问题。结合TM5码率控制算法和拼接过程中已解码图像的信息，提出了一种有效的码率控制算法．该算法首先通过计算待拼接视频流中的vd(vbv—delay)值来求取拼接期的目标比特数。然后根据图像原来的量化参数估计宏块的空间活动性，最后利用已解码图像中的比特数分布情况来指导虚拟缓冲器充溢度的调整．实验结果表明：该算法能非常有效地实现无缝拼接，且拼接后视频流的vd值与新视频流的vd值非常吻合，并能有效保证图像的降质在允许的范围之内．     

气流纱的拉伸特性研究

本文讨论气流纱的拉伸特性。Hearle曾对具有理想结构纱线的拉伸特性进行过比较完整的研究工作。本文则根据气流纱独特的成纱结构,对Hearle理论在气流纱中的应用作了一定的修正,并在此基础上对气流纱的拉伸特性作了分析计算。计算结果与实测结果基本相符。最后还从气流纱的应力-应变关系式中,就影响气流纱强力、初始模量以及断裂功等等力学特性的一些主要工艺参数进行了分析讨论。得出合理选用阻捻盘、很好控制捻度传递长度;合理设计与选用分梳及输棉机构,在不断改善单纤维供应的同时,尽量减少纤维损伤,提高纤维有效长度;适当提高纺纱张力,增加纤维转移等等都是改善气流纱强力等力学特性、提高成纱质量的有效途径。对工业用气流纱,还可通过合理设计凝棉槽,以提高气流纱紧密度的途径来提高气流纱强力。     

自动络筒机空气捻接器的捻接原理研究

研究自动络筒机空气捻接器的捻接原理.对退捻后纱线尾端的曲线函数进行研究,指出了一种合理的纱线尾端的曲线函数,并利用流体力学原理,具体描述了纱线在捻接孔内的运动,揭示了纱线捻接原理.     

三维机织物增强复合材料板材的研制

以玻璃纤维为原料,试织了4种结构的三维机织物,并采用手糊成型工艺制成三维机织物增强的复合材料板材,测试并分析了4种复合材料板材的拉伸性能和层间剪切性能.研究表明:织物的结构对拉伸力学性能的影响主要是织物内部纱线的屈曲程度和垂纱的贡献,对层间剪切性能的影响主要取决于垂纱参与层间连接的程度.     

热塑性聚氨酯弹性体黏合剂的加工流变性能研究

利用转矩流变仪研究了不同硬段质量分数的热塑性聚氨酯弹性体黏合剂在不同加工条件下的流变性能,表征了加工后热塑性聚氨酯弹性体黏合剂的力学性能.实验结果表明,加工工艺对热塑性聚氨酯弹性体黏合剂的流变性能有显著影响,其平衡转矩随着加工温度和转速的提高呈下降趋势.加工工艺对热塑性聚氨酯弹性体黏合剂的力学性能也有一定的影响,加工温度和转速的提高使其拉伸强度降低,而延伸率则随着加工温度的提高有所增加.