谈生态农业体系建设

生态农业体系建设是人类文明进步对农业发展提出的最高要求和发展目标。文章简述了生态农业的含义、生态农业体系的特点、要求，生态农业体系建设的思路和方法。     

羧基丁腈橡胶的制备及在耐温环氧胶中的应用

采用接枝的方法在丁腈-40分子链中接入羧基,获得了高门尼黏度的羧基丁腈橡胶,并用其对环氧树脂进行改性,从而制备出耐高温环氧树脂结构胶。通过加入促进剂可将固化温度从180℃降至120℃。     

环氧增韧剂的合成及其在胶粘剂中的应用

为了开发新型的环氧增韧剂,合成了一系列环氧基封端的多元醇,对其在环氧树脂体系中的粘接性能进行了研究。试验结果表明,与未改性的环氧树脂体系相比,应用新型增韧剂改性的环氧树脂体系,其剪切强度提高59.8%,剥离强度提高108%。     

聚硫密封胶耐老化性能研究

以环氧改性液体聚硫密封胶为基胶,研究了环氧树脂、液体聚硫橡胶、填料、防老剂种类及用量对聚硫密封胶常温拉伸性能及老化后拉伸性能的影响.结果表明,通过环氧改性聚硫橡胶,可有效提高聚硫密封胶的扯断伸长率及耐热老化性能.填料对聚硫密封胶均有一定的补强效果,炭黑的补强效果最好,A-380的耐热老化性能最好.防老剂D可有效提高聚硫...     

SIS的环氧化反应

研究了ＳＩＳ在甲苯溶剂中的环氧化反应,得到了甲苯溶剂中ＳＩＳ环氧化反应的适宜条件：ＳＩＳ溶液浓度为１５％,甲酸／过氧化氢（摩尔比）＝１．５：１,反应温度５０℃,反应时间２小时。所得产物的环氧含量为３．３５０ｍｏｌ／Ｋｇ。     

环氧化SBS胶粘剂的研制

研究了环氧化SBS橡胶胶粘剂的合成及应用。试验结果表明环氧化SBS胶粘剂在粘接极性材料时的性能要优于SBS胶粘剂。     

非异氰酸酯聚氨酯固化剂的制备及性能研究

以间苯二酚二缩水甘油醚为原料,通过CO2插入法合成环碳酸酯化合物（RDGEC）。将其与聚醚胺（D230）聚合,调控比例,制备了系列非异氰酸酯聚氨酯（NIPU）固化剂。详细考察了NIPU与双酚A环氧树脂（E-51）共混体系的固化动力学,对固化试样的粘接性能、热机械性能、热稳定性及断裂面的微观状态进行了研究。研究结果表明：成功制备了RDGEC和系列NIPU固化剂;调控RDGEC与D230反应比例对NIPU的固化反应活性影响较小,但能够有效改变固化体系韧性程度,确定固化工艺为50℃/2 h+100℃/2 h;NIPU与E-51混合固化体系对铝合金具有优异的粘接性能,调控RDGEC与D230比例至1∶1.75时,25℃剪切强度和70℃剪切强度分别为36.98和14.51 MPa,25℃下90°剥离强度达到6.08 kN/m,粘接性能达到最佳;该系列固化试样均表现出优异的热机械性能和热稳定性。     

DSC分析在聚酯生产中的应用

通过聚酯产品的DSC测试谱图信息,剖析不同情况下聚酯切片及瓶胚的特性,提出了利用DSC测试进行聚酯切片的异物分析、切片来源判断、结晶性能评价、用户投诉样品剖析以及新产品开发时工艺调整的建议,进一步说明DSC测试在聚酯生产、品质控制工作中的重要作用。     

原位生成SiO_2改性硼硅酚醛树脂的合成与性能研究

在合成酚醛树脂的过程中引入有机硅预聚物和硼酸,制得硼硅酚醛树脂,并在此基础上加入正硅酸乙酯,原位水解生成SiO 2,进一步改性了硼硅酚醛树脂。分别考查了有机硅预聚物、硼酸和正硅酸乙酯加入量对改性酚醛树脂粘接强度的影响。通过IR考查了改性树脂的结构,硼氧键和硅氧键成功地引入到酚醛树脂中。还通过DSC和不同条件下粘接强度的测试考查了改性树脂的固化性能,确定了其固化工艺。空气气氛中的热重分析则表明改性酚醛树脂初始分解温度为475℃,1 000℃残炭率为21%,耐热性明显优于普通酚醛树脂。     

Study on the influence of three-grid assembly thermal deformation on breakdown times and an ion extraction process

In order to study the influence of three-grid assembly thermal deformation caused by heat accumulation on breakdown times and an ion extraction process,a hot gap test and a breakdown time test are carried out to obtain thermal deformation of the grids when the thruster is in 5 k W operation mode.Meanwhile,the fluid simulation method and particle-in-cell-Monte Carlo collision(PICMCC) method are adopted to simulate the ion extraction process according to the previous test results.The numerical calculation results are verified by the ion thruster performance test.The results show that after about 1.2 h operation,the hot gap between the screen grid and the accelerator grid reduce to 0.25–0.3 mm,while the hot gap between the accelerator grid and the decelerator grid increase from 1 mm to about 1.4 mm when the grids reach thermal equilibrium,and the hot gap is almost unchanged.In addition,the breakdown times experiment shows that 0.26 mm is the minimal safe hot gap for the grid assembly as the breakdown times improves significantly when the gap is smaller than this value.Fluid simulation results show that the plasma density of the screen grid is in the range 6?×10~(17)–6?×?10~(18) m~(13) and displays a parabolic characteristic,while the electron temperature gradually increases along the axial direction.The PIC-MCC results show that the current falling of an ion beam through a single aperture is significant.Meanwhile,the intercepted current of the accelerator grid and the decelerator grid both increase with the change in the hot gap.The ion beam current has optimal perveance status without thermal deformation,and the intercepted current of the accelerator grid and the decelerator grid are 3.65 m A and 6.26 m A,respectively.Furthermore,under the effect of thermal deformation,the ion beam current has over-perveance status,and the intercepted current of the accelerator grid and the decelerator grid are 10.46 m A and 18.24 m A,respectively.Performance test results indicate that the breakdown times increase obviously.The intercepted current of the accelerator grid and the decelerator grid increases to 13 m A and 16.5 m A,respectively,due to the change in the hot gap after 1.5 h operation.The numerical calculation results are well consistent with performance test results,and the error comes mainly from the test uncertainty of the hot gap.