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1.
改性酚醛树脂胶粘剂的研究   总被引:11,自引:0,他引:11  
采用常规合成树脂胶进行多层地板贴面时,很容易造成开胶或胶液透胶现象.通过缩合物的共混共缩聚方法,采用三聚氰胺尿素甲醛树脂对酚醛树脂进行改性,探讨了三聚氰胺尿素树脂的加入量、酚醛树脂物质的量比、混合比、热压条件等对胶液的粘度、缩合度、稳定性、胶层颜色及胶合质量的影响.结果表明,改性后的浅色酚醛树脂胶粘剂贮存性好,固化后胶层无色,具有强耐水、耐候性,所压制的多层实木复合地板达到GB9846.1~12-88Ⅰ类胶合板标准.  相似文献   

2.
竹帘板胶合强度的研究   总被引:2,自引:0,他引:2  
以二次正交施转组合设计为数学模型,系统地研究了五个变量因子对竹帘板胶合强度的非线性影响,得出了回归方程,并利用正交设计计算法优化了工艺。结果表明:当选用涂胶量225g/m^2,增强剂添加量8%,热压条件:温度105℃,压力3.65MPa和加压时间8.4min的优化工艺时,胶合强度达到了回归方程的预测值1.36MPa,超过日本普通2类胶合板要求。此外,竹片间隙对胶合强度也有较大影响。  相似文献   

3.
本文报道了采用硝酸氧化工艺生产对硝基苯甲酸的小试,研究了反应物用量、反应温度和压力等工艺条件。采用间歇式操作,最佳反应条件为对硝基甲苯与硝酸的摩尔比在1:2.2~1:4.0,硝酸浓度在20%~45%,反应温度在150~220℃,反应压力在1~4MPa,反应时间0.5~2h产率高达95%以上  相似文献   

4.
利用油菜籽分离蛋白(RPI)和聚醋酸乙烯酯(PVAc)乳液制备高性能无醛胶黏剂,代替部分醛类胶黏剂.通过正交试验考察RPI与葡萄糖质量比、改性RPI与PVAc乳液质量比、改性RPI与PVAc乳液共混温度、固化剂质量分数对共混胶黏剂剪切强度的影响,优化热压工艺.结果表明:共混胶黏剂的最佳制备工艺为RPI与葡萄糖质量比85∶15、改性RPI与PVAc乳液质量比7∶3、改性RPI与PVAc乳液共混温度30℃、固化剂质量分数3%;制备胶合板的最优热压工艺参数为热压温度140℃、热压时间1.5 min/mm、热压压力0.8 MPa、施胶量300 g/m2,胶合板干剪切强度为1.865 MPa,按照Ⅱ类板胶合板标准测得湿剪切强度为0.885 MPa.  相似文献   

5.
包头2号矿体选冶经济高效流程的开发   总被引:2,自引:0,他引:2  
采用包头2号矿体的重选粗精矿(含Nb2O51.6%~1.8%),用磁化焙烧-磁选,交流等离子冶烧工艺流程,可获得低磷中级铌铁(含铌22%~32%,Nb/P〉30),铌收率61.1%,同时获得含铌铁精矿(TFe〉60%,Nb2O5~1.0%)流程短效率高而经济。  相似文献   

6.
为了实现专业运输液化天然气(LNG)船特种绝缘箱用桦木胶合板的国产化,采用我国东北桦木及水溶性酚醛树脂胶黏剂压制LNG船用特种绝缘箱用胶合板。以热压压力、温度和时间3因素安排正交实验,以密度、弹性模量(MOE)、静曲强度(MOR)和剪切强度为指标,确定最优工艺为:热压压力1.2 MPa,热压温度140℃,热压时间1.0 min/mm。同时对桦木胶合板常态下,以及浸泡于液态天然气(-162℃),48 h后的MOE、MOR、剪切强度、厚度变化进行比较。结果表明:LNG船浸泡处理导致桦木胶合板MOE、MOR和剪切强度降低,试件厚度膨胀率为0.96%。压制的东北桦木胶合板与芬兰同样结构的桦木胶合板的性能比较表明,以优化工艺压制的东北桦木胶合板可以替代芬兰桦木胶合板用于LNG船绝缘箱。  相似文献   

7.
对(l-×)(80%B4CC-20%SiC)/x C(体积分数)功能梯度材料的 ×=0. 2, 0.4, 0.6, 0.8的各层 分别在2000℃,20MPa进行了热压,测定了各层的密度,线膨胀系数,弹性模量和抗弯强度等. 按线性成分分布函数的6层和11层梯度材料热压后都出现了裂纹.采用了不同于幂函数的S 型成分分布函数设计,热压了11层(×=0.2~1.0)的功能梯度材料,其抗弯强度为216MPa,抗热震 性>500℃.  相似文献   

8.
在50、100和200mmol/l下,研究了NaCI、Na2SO4和Na2CO3对小麦高生长、生物量生长、脯氨酸及Na+,K+含量的影响。NaCI处理使高度下降8.8%~35.4%、而Na2SO4和Na2CO3分别为8.8%~77.9%和53.1%~100.0%。NaCI处理使鲜重和干重分别降低14.3%~42.9%和6.1%~36.7%,而Na2SO4处理分别为14.3%~64.3%和7.2%~58.9%,Na2CO3处理分别为50.0%~74.1%和48.3%~72.8%。在NaCI、Na2SO4和Na2CO3处理下,脯氨酸含量分别增加0.0%~66.7%、0.0%~33.3%和66.7%~100.0%。Na+/K+分别提高2.5~11.9、3.6~114.1和35.1~156.6倍。结果表明:Na2CO3的胁迫比Na2SO4强,而Na2SO4的胁迫影响又比NaCl强  相似文献   

9.
采用高频介质加热技术,研究了不同含水率条件下的多层豆胶胶合板板坯温度场分布和水分迁移情况,以及单板涂胶量对豆胶胶合板胶合性能的影响。结果表明:在高频热压(频率为6.78 MHz,压力为1.0 MPa)过程中,板坯内部温度场分布均匀; 干燥效率呈现出从表层向芯层逐渐增加,即由里到外的干燥模式; 当单板双面涂胶量为400 g/m2时,胶层平均湿态剪切强度为0.83 MPa,高频热压时间仅为12 min。  相似文献   

10.
淀粉—KI体系光度法测定微量铜(Ⅱ)的研究   总被引:1,自引:0,他引:1  
本文利用碘与淀粉的高灵敏显色反应,建立了光度法测定微量铜的新分析方法。该法简单易行,灵敏准确.Cu2+离子浓度在1.0×10-6~6.0×10-5mol.L-1区间符合比耳定律,检测限为5×10-7mol.L-1。对水样中微量铜的测定.回收率在98.2%~99.6%之间变化,RSD为2.2%和2.5%。  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

13.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

14.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

15.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

16.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

17.
There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.  相似文献   

18.
本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。  相似文献   

19.
20.
The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to  相似文献   

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