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1.
具有磁性的非均相催化剂价格低廉、低污染、高能效、容易从溶液中分离出来。经过水热合成法合成的Fe3O4/MnO2磁性复合氧化物催化剂在活化过一硫酸盐(2KHSO5·KHSO4·K2SO4)产生硫酸根自由基(SO4-)降解水中有机污染物表现出了优良的性能。把不同质量的磁性Fe3O4微球与线状的MnO2负载到一起,合成三种Fe3O4:MnO2质量比分别为1:3、2:3、1:1的Fe3O4/MnO2催化剂,经过XRD、SEM和TEM表征,表明这两种金属氧化物负载到一起。对比不同Fe3O4:MnO2质量比的Fe3O4/MnO2磁性复合氧化物催化剂活化2KHSO5·KHSO4·K2SO4的活性,发现Fe3O4/MnO2(2:3)催化剂催化活性最高。通过考察不同因素对Fe3O4/MnO2(2:3)催化活性的影响得出,水中罗丹明B(Rh B)降解的最佳条件为10 mg/L Rh B、0.4 g/L Fe3O4/MnO2催化剂、0.3 g/L 2KHSO5·KHSO4·K2SO4、pH=8。Fe3O4/MnO2(2:3)磁性复合氧化物催化剂经过3次循环利用后,催化活性没有明显下降。SO4-在降解水中Rh B起主要作用。   相似文献   

2.
为研究单基发射药孤石爆破特性,利用直径和高度均为50 cm的水泥砂浆试块模拟孤石,开展了0.05~0.25 kg/m3单耗的单基发射药和乳化炸药孤石爆破实验,统计并分析了单基发射药和乳化炸药爆破试块的块度分布、破碎能及能量利用率随单耗的变化规律。结果表明:乳化炸药爆破孤石的最大块度随单耗的增加,但能量利用率变化不大。结合高速摄影观察对比单基发射药和乳化炸药爆破孤石的表面裂纹分布与扩展结果,发现单基发射药破岩模式与乳化炸药存在显著差异,其破岩模式是通过在炮孔内快速燃烧产生的高压气体使试块发生轴向和环向的拉伸破坏,而当试块完全开裂后剩余的发射药不再提供破岩能量。  相似文献   

3.
为研究叠氮硝胺发射药与赛璐珞药盒的长储稳定性,采用差示扫描量热法(DSC)和真空安定性法(VST)研究分析了叠氮硝胺发射药与赛璐珞片的化学相容性,采用GJB736.8—1990火工品试验71 ℃试验法研究分析了叠氮硝胺发射药与赛璐珞药盒之间的组分迁移性。DSC试验表明,叠氮硝胺发射药与赛璐珞片混合体系的热分解峰温降低,降低值为0.5 ℃,混合体系相容;VST试验表明,混合体系净增放气量R为0.3 mL/g,混合体系相容;71 ℃试验法储存26 d后,叠氮硝胺发射药中的增塑剂(DIANP、NG)质量分数由39.82%降低到33.67%,药盒中增塑剂(DIANP、NG)质量分数由0增加到33.89%,发射药与药盒之间存在增塑剂的迁移。叠氮硝胺发射药与赛璐珞药盒化学相容性良好,但物理安定性差,存在增塑剂的迁移,加速老化10 d后,体系浓度达到平衡。  相似文献   

4.
五水硫代硫酸钠(Na2S2O3·5H2O)相变储能材料具有较高的相变潜热、储能密度等,但Na2S2O3·5H2O存在过冷和相分离,性能较不稳定。添加成核剂K2SO4、CaSO4·2H2O、Na4P2O7·10H2O和强化传热材料膨胀石墨(EG)进行改性,制备得到性能稳定的EG/Na2S2O3·5H2O相变储能复合材料。测试结果显示:K2SO4对Na2S2O3·5H2O的成核性较差,CaSO4·2H2O、Na4P2O7·10H2O均有较好的成核作用,可明显降低Na2S2O3·5H2O过冷度,但CaSO4·2H2O体系不稳定,添加3.0%质量分数的Na4P2O7·10H2O可使Na2S2O3·5H2O过冷度降低至1℃以内,0.5%~2.0%质量分数的EG可使其过冷度降低至2℃左右,7.0%质量分数的EG可完全消除体系的相分离。复合相变材料的较优组成为7.0%的EG、3.0%的Na4P2O7·10H2O和90.0%的Na2S2O3·5H2O。此时,EG/Na4P2O7·10H2O/Na2S2O3·5H2O复合材料相变潜热为192.5 kJ·kg-1,相变时无液态泄露,无相分离,储热时间比纯物质缩短22.3%,放热较快。   相似文献   

5.
制备了聚苯胺包覆CoFe类普鲁士蓝纳米立方(CoFePBA@PANI)复合材料,采用XRD、FTIR、SEM和TEM对CoFePBA@PANI复合材料的结构和形貌进行表征,利用循环伏安法(CV)、恒电流充放电法及交流阻抗法(EIS)对CoFePBA@PANI复合材料的电化学性能进行了考察。结果表明:通过植酸的配位作用促使苯胺在具有面心立方结构的CoFePBA表面发生聚合反应,形成了具有核-壳结构的CoFePBA@PANI复合材料。系统地研究了PANI的含量对CoFePBA@PANI复合材料电化学性能的影响,CoFePBA@PANI复合材料在0.5 mol/L Na2SO4和H2SO4的混合酸性介质中,在1 A/g电流密度下,比电容值达到401.2 F/g,电流密度增大至10 A/g时,比电容仍能保持在367.3 F/g。   相似文献   

6.
为了研究挤出过程中超临界二氧化碳(SC-CO2)对高固含量发射药停留时间分布的影响,采用示踪粒子轨迹跟踪技术研究了醋酸纤维素(CA)/碳酸钙(CaCO3)/SC-CO2代料停留时间的影响因素,结合反应器流动模型确定了CA/CaCO3/SC-CO2在机筒中的流动情况。数值模拟结果显示,注入体积流量为0.1 mL/min的SC-CO2后,平均停留时间缩短了35%,Pe减小了196.4;螺杆转速由6 r/min增加到14 r/min时,平均停留时间缩短了54.5%,Pe减小了210.8;当机筒温度从40 ℃升高至60 ℃,平均停留时间减少了19%,Pe减小了75.0。反应器流动模型拟合结果显示,螺杆转速由6 r/min增加到14 r/min时,CA/CaCO3/SC-CO2的体积分数从0.65降低到0.62。由此可知,SC-CO2的加入、螺杆转速的增加以及机筒温度的升高都显著缩短了物料的停留时间,并促进了轴向混合,CA/CaCO3/SC-CO2在螺杆内的主要流型为活塞流。  相似文献   

7.
采用溶液燃烧法制备不同B位过渡金属元素(Mn、 Fe、 Co、 Ni)的La基钙钛矿(LaMO3)催化剂,并考察少量Sr部分取代La对催化剂性能的影响;通过XRD、 SEM、 BET、 H2-TPR、XPS方法对催化剂进行理化性质表征,采用程序升温氧化(TPO)技术评估催化剂催化碳烟燃烧的性能。结果表明:溶液燃烧法制备的La基催化剂具有典型的钙钛矿结构,少量Sr掺杂不改变催化剂的晶型;Sr掺杂LaMnO3引起的电荷不平衡由增加的Mn4+补偿,Sr掺杂LaCoO3使吸附氧量明显提高;La0.9Sr0.1MnO3和La0.9Sr0.1NiO3的氧化还原性能相比掺杂Sr之前的有所下降,La0.9Sr0.1FeO3表面吸附氧物种量增多,催化剂的低温氧化还原性提升;气氛中NOx  相似文献   

8.
为了改善铝热剂的点火和燃烧性能,采用均匀设计法对Al-Fe3O4、Al-Ba(NO3)2和Al-MnO2进行配方优化设计,然后选用SPSS(statistical program for social sciences)软件进行二次回归分析,确定了一种铝热剂配方,并外掺占其质量25%的黏结剂,获得复合铝热剂。研究其燃烧性能,试验结果表明,该复合铝热剂点燃性能好,燃烧过程分成两个阶段,整个燃烧时间持续约140 s,最高燃烧温度达1 893.32 K,能够形成较好的高温纵火效果,30 g复合铝热剂能够可靠熔穿2 mm铝板。  相似文献   

9.
以通过溶胶-凝胶法制备的中空介孔SiO2(HMSiO2)纳米微球为骨架材料,通过反相微乳液合成使天然高分子壳聚糖(CTS)沉积在HMSiO2纳米微球表面,随后在铈离子引发下于CTS表面进行丙烯腈接枝共聚并偕胺肟化,制备HMSiO2复合壳聚糖接枝聚偕胺肟(PAO)复合纳米粒子(HMSiO2@CTS-g-PAO)。通过FTIR和XRD对HMSiO2@CTS-g-PAO复合纳米粒子的结构进行表征。采用SEM和激光粒度分析仪对HMSiO2@CTS-g-PAO复合纳米粒子的形貌和粒径进行探究。结果表明:HMSiO2@CTS-g-PAO复合纳米粒子的内层为HMSiO2,外层为CTS-g-PAO,是典型的核-壳纳米粒子。以K2Cr2O7为Cr源,探究HMSiO2@CTS-g-PAO复合纳米粒子对Cr的吸附。结果表明,HMSiO2@CTS-g-PAO复合粒子对Cr的吸附过程符合伪二级吸附动力学,主要为化学吸附,对pH=2.0、浓度为91.4 mg/L的K2Cr2O7溶液中铬的最大吸附量高达3.28 mmol/g。  相似文献   

10.
为了进一步提高NiCrAlY涂层的抗热腐蚀性能,利用电弧离子镀技术在DZ125合金表面分别沉积NiCrAlY/NiAl/Al涂层(coating A)、NiCrAlY/Pt/NiAl/Al涂层(coating B),再经真空扩散退火处理形成成分渐变的梯度涂层结构。在涂层中引入改性元素Pt以改善涂层的抗热腐蚀能力,对比研究了2种涂层体系在900℃不同混合盐中的热腐蚀行为;利用SEM、EDS、XRD以及EPMA分析了涂层经过热腐蚀后的微观形貌、物相组成和元素分布。结果表明:在900℃的K2SO4+Na2SO4混合盐中,coating A表面的氧化膜发生了大面积的剥落,coating B中的Pt抑制了S在涂层/氧化膜界面处的偏析,增强了氧化膜的黏附性。在900℃的NaCl+Na2SO4混合盐中,coating A的Cr元素和O元素分别发生了外扩散和内扩散,Cr外扩散易与S反应生成有害相CrxSy。coating B中的...  相似文献   

11.
The composite films of ferroelectric potassium nitrate (KNO3):poly(vinyl alcohol) (PVA) with different weight percentages of KNO3 have been prepared at 200°C using the spray-deposition technique. The remanent polarization (Pr) and peak current density for all composite films was estimated by tracing the polarization-electric field (P-E) hysteresis loop and current density-electric field (J-E) loop, respectively, using a modified Sawyer-Tower circuit. Pure KNO3 is known not to exhibit any ferroelectricity under ambient conditions, but the X-ray diffraction (XRD) studies of PVA:KNO3 composite films reveal the presence of a ferroelectric phase III of KNO3 in the composite films at room temperature. The composite film containing KNO3:PVA in equal proportions shows maximum Pr and peak intensity ratio of approximately 20.10 μC/ cm2 and 2.67, respectively, at room temperature. The J-E and capacitance voltage (C-V) characteristics exhibit butterfly features that supports the presence of a ferroelectric phase in the composite films. The field emission scanning electron microscopy (FE-SEM) image of the composite film containing equal proportions of KNO3 and PVA shows the homogenous distribution of spherical grains of KNO3 of size ~225 nm.  相似文献   

12.
Electron Paramagnetic Resonance (EPR) spectra of K2SO4---Na2SO4---ZnSO4 glasses containing 3 mol.% of vanadium sulphate have been studied. Spin-Hamiltonian parameters (g, g, A, A), the dipolar hyperfine coupling parameter (P), the Fermi contact interaction parameter (K) and the tetragonality of the V4+ site (Δgg) have been calculated. The optical absorption spectra of VO2+ ions doped these glasses show three bands. By correlating the EPR and optical spectral data, the molecular orbital parameters have been evaluated. Results agree with similar studies made earlier.  相似文献   

13.
为了研究纳米氧化铜(CuO)改性硼(B)对镁/聚四氧乙烯(Mg/PTFE)富燃料推进剂的影响,利用球磨法制备了B/CuO复合燃料,将其添加到Mg/PTFE富燃料推进剂中,利用混合模压成型法制备含有不同比例的复合燃料的推进剂药柱。利用扫描电镜、TG-DSC分别测试了B/CuO复合燃料的微观形貌和热反应性能;利用红外测温仪、X射线衍射、TG-DSC分别测试了推进剂的燃烧速度、燃烧温度、反应产物以及热反应性能。结果表明:复合燃料混合较为均匀,局部有团聚;n(B)∶n(CuO)=32∶3的复合燃料的放热量高于B的放热量,燃烧效率最高,为73.1%,点火温度比B低66 ℃。含此复合燃料的推进剂的燃烧速度和质量燃烧速度均高于Mg/PTFE,分别提高了25.6%和3.1%,平均燃烧温度降低了16 ℃,最高燃烧温度则提高了6 ℃,但是相对于含B的Mg/PTFE推进剂,含此复合燃料的推进剂的燃烧速度和质量燃烧速度分别下降2.91%和19.51%,平均燃烧温度下降了94 ℃和121 ℃;复合燃料推进剂一次燃烧的凝聚相产物主要有MgF2、MgO、C、Cu以及Mg3F3(BO3);一次燃烧反应过程主要是PTFE的分解以及F2和Mg的反应,二次燃烧反应过程则主要为C、Mg以及复合燃料的氧化。  相似文献   

14.
Polyaniline (PANI) salts doped with inorganic acids (HCl, H2SO4 and H3PO4) were directly synthesized by using solid-state polymerization method. The FTIR spectra, UV–vis absorption spectra and X-ray diffraction patterns were used to characterize the molecular structures of the PANI salts. Voltammetric study was done to investigate the electrochemical behaviors of all these PANI salts. The PANI salts were affected by varying the protonation media (HCl, H2SO4 and H3PO4). The FTIR and UV–vis absorption spectra revealed that all PANI salts contained the conducting emeraldine salt phase at different oxidation state. The crystallinity of PANI doped with HCl was better than those doped with H2SO4 and H3PO4. The conductivity of the PANI doped with HCl is the highest among the inorganic acid doped PANI.  相似文献   

15.
利用六钛酸钾晶须(K2O·6TiO2)对苯并噁嗪(BOZ)树脂及玻璃纤维/苯并噁嗪(GF/BOZ)复合材料的摩擦磨损性能进行改性,分析了K2O·6TiO2/BOZ复合材料以及K2O·6TiO2-GF/BOZ混杂复合材料的摩擦磨损性能以及改性机理。结果表明:因K2O·6TiO2的加入,K2O·6TiO2/BOZ复合材料以及K2O·6TiO2-GF/BOZ混杂复合材料的摩擦系数和比磨损率较纯BOZ树脂和GF/BOZ复合材料的明显降低。K2O·6TiO2显著减轻了BOZ树脂和GF/BOZ复合材料的摩擦粘着状况,使摩擦系数降低,同时磨粒磨损情况也大为减轻。GF/BOZ复合材料在摩擦过程中摩擦应力通过率先破坏GF和BOZ树脂的界面,进而诱发破坏GF束内、GF束间和层间BOZ树脂,使得GF/BOZ复合材料的摩擦系数比BOZ树脂降低,但比磨损率较BOZ树脂升高,而K2O·6TiO2的加入,使K2O·6TiO2-GF/BOZ混杂复合材料的比磨损率有效降低。BOZ树脂、GF/BOZ、K2O·6TiO2-GF/BOZ 3种材料的摩擦系数和比磨损率分别为0.34和0.66×10-6 mm3·(N·m)-1,0.19和1.2×10-6 mm3·(N·m)-1,0.09和0.69×10-6 mm3·(N·m)-1。   相似文献   

16.
为了降低发射药的敏感性,以Bu-NENA为增塑剂,FOX-7和RDX作为填充物研制了一种新型硝化棉(NC)基发射药(GD-3发射药),对其装药进行了低易损性能测试研究。试验结果表明,GD-3发射装药在慢速烤燃和快速烤燃、子弹撞击刺激源下发生了V类燃烧反应,在特定的空心装药射流刺激下发生了III类爆炸反应。GD-3发射药在刺激源下易损性响应剧烈程度弱于硝基胍发射药和单基发射药,该新型装药符合低易损性弹药的性能评定要求。  相似文献   

17.
Polyacrylonitrile (PAN) based high strength carbon fibers were anodically oxidized using the galvanostatic mode in alkaline electrolyte solutions to influence the chemical surface composition. The change of chemical and physical properties was investigated using scanning electron microscopy (SEM), photoelectron spectroscopy (XPS), energy dispersive X-ray analysis (EDX) and contact angle as well as zeta (ζ)-potential measurements.

An initially improved wettability for polar liquids, particularly water, was observed for oxidized carbon fibers. This result was confirmed by ζ-potential measurements. The chemical state of the oxygen containing surface groups changes during anodic oxidation in K2CO3/KOH due to further oxidation of C–OH and C=O groups to COOH groups. Therefore the surface acidity increases, which leads to a shift of the isoelectric point to lower pH values and increases the negative ζplateau value. The ζ–pH as well as the ζ–concentration dependence show the same tendency. During anodic oxidation of carbon fibers in KNO3/KOH electrolyte solution beside ‘normal’ (like C–OH, C=O and COOH) surface oxides also carboxylate groups (COOK+) were formed at the fiber surface in contrast to an oxidation in K2CO3/KOH which introduces ‘normal' surface oxides. No influence could be observed of such an anodic oxidation on the single fiber tensile strength. Contact angle measurements of polycarbonate melt droplets onto single carbon fibers show no dependence of the surface composition. The interfacial shear strength, measured using the microdroplet pull-off test were compared with the thermodynamic work of adhesion. The calculated as well as the measured adhesion show the same absence of any influence of fiber treatment.  相似文献   


18.
In this paper, double hydrophilic ionic liquid block copolymers (ILBCs), poly(N-isopropylacrylamide)-block-poly[1-methyl-3-(2-methacryloyloxy propylimidazolium bromine)] (PNIPAM-b-PMMPImB), were polymerized by two-step reversible addition-fragmentation chain transfer (RAFT) process. The?composition and molecular weight distributions of ILBCs were characterized using 1HNMR and gel permeation chromatography (GPC). The self-assembly and temperature- and anion-responsive behaviors of ILBCs were investigated by UV-Vis spectroscopy, TEM and dynamic light scattering (DLS). With increasing the concentration of (CF3SO2)2N--, the micellization of self-assembling PNIPAM-b-PMMPImB was induced to form a core--shell structure containing the core with hydrophilic PMMPIm-(CF3SO2)2N-- surrounded by the shell of PNIPAM via the anion-responsive properties of ILBCs. However, upon temperature increasing, PNIPAM-b-PMMPImB formed the micelles composing of PNIPAM core and PMMPImB shell. The ionic liquid segment with strong hydrophilic property enhanced the hydrogen bonding interaction which expanded the temperature range of phase transition and increased the lower critical solution temperature (LCST) of the system. These results indicate that ILBCs prepared in this paper have excellent temperature and anion double responsive properties, and may be applied as a kind of potential environmental responsive polymer nanoparticles.  相似文献   

19.
Electrodeposition of conducting polyaniline (Pani) was made under potentiostatic condition at pH 1.0 in different electrolyte media (H2SO4 and HClO4) in the absence and presence of two organic dopants, disodium salts of naphthalene-1,5-disulphonic acid (NSA) and of catechol-3,5-disulphonic acid (CSA). The rate and yield of Pani deposition were dependent on the acid medium and the dopant employed. NSA in H2SO4 caused an increase in rate and yield but CSA decrease when compared to the rate and yield of H2SO4 alone. In HClO4 medium, both the dopants showed a decrease. With regard to DC electrical conductivity, both the dopants exhibited an enhancement in H2SO4 medium but NSA a decline in HClO4. Characterisation of the electrosynthesised polymer samples by various instrumental techniques (cyclic voltammetric: CV, FTIR, UV-Visible: UV-Vis, EPR, XRD, TGA and DTG methods) revealed that between the two acid media, H2SO4 was the better one. Further, it enlightened the role of two organic dopants in relation to the acid media. The advantageous role of NSA in H2SO4 had origin on its molecular characteristics such as non-polarity, larger π-electron cloud etc., while CSA could not perform such a role because of its easily oxidisable hydroxyl groups. In HClO4, however, both the dopants could play only an unfavourable role owing to its greater polarity and oxidizing power than H2SO4.  相似文献   

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