Strain effect on recovery behaviors from circular deformation of natural rubber vulcanizate

The recovery behaviors of vulcanized natural rubber from circular deformation were studied by varying sample length to investigate the influence of the degree of applied strain to the sample. The stress and strain varied uniformly across the thickness of the sample, and the degree of applied stress and strain to the sample decreased with increasing the sample length. The linear sample was made into a circular form and thermally aged in a convection oven. The recovery was measured after removing from the circular deformation. The recovery increased by decreasing the sample length. The difference in recoveries of the samples with different lengths reduced at high temperature. The short sample had higher heat‐resisting property for recovery than the long sample. The experimental results were explained by the rearrangement and stabilization of the deformed rubber chains as well as the crosslink density change. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

天然橡胶防腐衬里自然硫化胶料的研制

简要介绍天然橡胶防腐衬里自然硫化胶料的基本配方、衬里的施工工艺及胶粘剂的情况。     

不同调控措施下烤烟开花时间与碳氮代谢关系的研究

通过田间试验对不同调控措施下烤烟开花时间进行了研究。结果表明,与对照相比,各处理均能推迟烤烟开花时间,增加有效叶片数,提高烟叶产质量;4个处理能明显提高叶绿素含量、NR活性和淀粉酶活性,增强烟株前期氮代谢,有利于个体形态构建,同时进入旺长期后可以使淀粉酶活性缓慢上升,抑制其过早进入生殖生长,使碳氮代谢更协调,从而达到控制和推迟早花的目的。     

胶料介电特性的全填充短路波导测试和分析

采用微波测试法中的全填充短路波导测试法测试炭黑胶料硫化过程中介电特性———介电常数εｒ和介电损耗因子ｔａｎδ的变化。测试分析结果表明,随着胶料交联密度增大,εｒ增大;炭黑粒径越小、比表面积越大、结构越高,胶料的ｔａｎδ越大;同一硫化条件下,ＮＲ、ＢＲ、ＳＢＲ、充油顺丁橡胶和充油丁苯橡胶胶料的εｒ顺次减小。     

一种新型橡胶填料—改性膨润土

介绍了改性膨润土在基础胶天然橡胶 (NR)和丁苯橡胶 (SBR)及橡胶制品轮胎当中的应用 ,结果表明 :(1)在NR和SBR中加入 10份改性膨润土不影响硫化胶的力学性能 ;(2 )在轮胎中加入 5～10份改性膨润土不但不影响轮胎半成品的力学性能 ,而且提高了橡胶与帘线的粘接强度 ;(3)改性膨润土易与SBR相混合。     

No reference image blurriness assessment with local binary patterns

In this paper, we put forward an effective and efficient no reference image blurriness assessment metric on the basis of local binary pattern (LBP) features. In this proposal, we reveal that part of the LBP histogram bins present monotonously with the degree of blurriness. The proposed method contains the following steps. Firstly, the LBP maps of an input image are extracted with multiple radiuses. And then, the frequency of pattern histogram is analyzed before part of bins are chosen as the features. In addition, we also take the entropy of these bins as another feature. Finally, we learn the extracted features to predict the image blurriness score. Validation of the proposed method is conducted on the blurred images of LIVE-II, CSIQ, TID2008, TID2013, LIVE3D IQA Phase I and LIVE3D IQA Phase II. Experimental results demonstrate that compared with the state-of-the-art image quality assessment (IQA) methods, the proposed algorithm has notable advantage in correlation with subjective perception and computational complexity.     

Wood flour: New filler for the rubber processing industry. IV. Cure characteristics and mechanical properties of natural rubber compounds filled by non‐modified or corona treated wood flour

It is presented here how some cure characteristics and mechanical properties of rubber compounds based on nonpolar rubber, natural rubber (NR), are affected by filling with conifer wood flour, both nonmodified or corona treated in air or in ammonia. The corona treatment was performed at room temperature and varied both: treatment duration and voltage to find out the maximal reinforcing effect of the modified wood flour. The discharge voltage was varied at 10, 12, and 15 kV to include both (1) the range of relative low voltages (lower than 10 ÷ 12 kV in which the major active species arise from ionized and activated air oxygen and (2) the range of relative high voltages (12 kV and higher) in which the active species arise from simultaneously ionized and activated air oxygen and nitrogen. The chemical composition of the nonmodified and corona‐treated wood surface was controlled by X‐ray photoelectron spectroscopy (XPS) analysis. The activity of the modified wood flour was evaluated by comparative measurement of some basic mechanical parameters of rubber compounds, filled at equal level by nonmodified or plasma‐treated wood flour. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 651–658, 2006     

加工条件对天然橡胶老化性能的影响

分别比较了由传统干混炼法和乳液相混合法制备的NR（天然橡胶）胶料的老化性能。与干混胶料相比,由乳液相法制备的胶料具有较好的耐老化性能和使用性能,这可能源于优良的炭黑分散和较高的相对分子质量。通过调节硫黄和促进剂用量,可以开发出比传统干混工艺胶料滞后性能好,同时,又具有同等或更好的老化性能的胶料。     

蒙脱土接枝插层改性胶乳与天然胶乳热降解动力学的研究

采用胶乳接枝插层法制备了蒙脱土接枝插层改性胶乳；采用热重分析法对天然胶乳（NRL）和蒙脱土接枝插层改性胶乳进行了等速升温热降解动力学研究。结果表明。NRL和蒙脱土接枝插层改性胶乳在氮气中的热降解过程相似。2者的热降解率（C）不受升温速率的影响；NRL和蒙脱土接枝插层改性胶乳的平衡起始降解温度相近，而后者的平衡最大降解率开始温度和终止温度均高于前者；NRL的反应级数为2．4，表观反应活化能为218kJ／mol,而蒙脱土接枝插层改性胶乳的反应级数为1．8，表观反应活化能为151．7kJ／mol。     

Effective identification of dominant fully absorbing sets for Raptor-like LDPC codes

The error-rate floor of low-density parity-check (LDPC) codes is attributed to the trapping sets of their Tanner graphs. Among them, fully absorbing sets dominantly affect the error-rate performance, especially for short blocklengths. Efficient methods to identify the dominant trapping sets of LDPC codes were thoroughly researched as exhaustively searching them is NP-hard. However, the existing methods are ineffective for Raptor-like LDPC codes, which have many types of trapping sets. An effective method to identify dominant fully absorbing sets of Raptor-like LDPC codes is proposed. The search space of the proposed algorithm is optimized into the Tanner subgraphs of the codes to afford time-efficiency and search-effectiveness. For 5G New Radio (NR) base graph (BG) 2 LDPC codes for short blocklengths, the proposed algorithm finds more dominant fully absorbing sets within one seventh of the computation time of the existing search algorithm, and its search-effectiveness is verified using importance sampling. The proposed method is also applied to 5G NR BG1 LDPC code and Advanced Television Systems Committee 3.0 type A LDPC code for large blocklengths.