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Oxidative esterification of acetol with methanol to methyl pyruvate over hydroxyapatite supported gold catalyst: Essential roles of acid-base properties 被引量:3
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作者 Yan Wan Congcong Zheng +6 位作者 Xianchi Lei Mengqi Zhuang Jinhan Lin Wenda Hu Jing dongLin Shaolong Wan Yong Wang 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2019年第11期1810-1819,共10页
Acetol is a major light oxygenate and readily produced from staged or fast pyrolysis of lignocellulose biomass. Herein we report that acetol can be selectively converted to methyl pyruvate, an important fine chemical,... Acetol is a major light oxygenate and readily produced from staged or fast pyrolysis of lignocellulose biomass. Herein we report that acetol can be selectively converted to methyl pyruvate, an important fine chemical, through oxidative esterification over Au-based catalysts. Detailed experimental studies showed that Au on amphoteric supports with appropriate strength and balanced ratio of acid and base sites can facilitate the desired oxidative-esterification pathway without accelerating undesired aldol-condensation or Cannizzaro reactions. In particular, hydroxyapatite (with a Ca/P ratio of 1.62) supported Au achieved 87% selectivity to methyl pyruvate at an acetol conversion of 62%. 展开更多
关键词 ACETOL acid-base properties GOLD HYDROXYAPATITE Methyl pyruvate
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Two Dehydroabietic Acid-based Arylamines: Synthesis, Crystal Structure and Fluorescent Properties 被引量:2
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作者 高宏 宋杰 +1 位作者 商士斌 宋湛谦 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 2013年第3期396-402,共7页
Two dehydroabietic acid-based arylamines have been synthesized and characterized by FTIR, 1H NMR, 13C NMR, MS spectra and elemental analysis. Their spatial structures were determined by X-ray diffraction analysis. UV-... Two dehydroabietic acid-based arylamines have been synthesized and characterized by FTIR, 1H NMR, 13C NMR, MS spectra and elemental analysis. Their spatial structures were determined by X-ray diffraction analysis. UV-Vis absorption and fluorescence spectral characteristics of these compounds in methanol were investigated. Their fluorescence emission spectra in different polarity solvents were further evaluated. Fluorescent properties and structural relationship of the compounds showed that fluorescence intensity and quantum yield inversely increase with the non-coplanar degree. In addition, the solvent polarity has different effects on the fluorescence emission spectra of two compounds. 展开更多
关键词 dehydroabietic acid-based arylamine SYNTHESIS crystal structure fluorescent property
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Acid-base and Electron Donor Properties of Pr_6O_(11)and Its Mixtures with Alumina
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作者 S.Sugunan G.D.Rani and P.A. Unnikrishnan(Dept. of Applied Chemistry, Cochin University of Science and Technology, Kochi, India) 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 1994年第6期425-429,共5页
The electron donor properties of Pr6O11 activated at 300, 500 and 800℃ are reported from the studies on adsorption of electron acceptors of various electron affinity (7, 7, 8, 8-tetracyanoquinodimethane , 2. 3. 5. 6-... The electron donor properties of Pr6O11 activated at 300, 500 and 800℃ are reported from the studies on adsorption of electron acceptors of various electron affinity (7, 7, 8, 8-tetracyanoquinodimethane , 2. 3. 5. 6-tetrachloro-1, 4-benzoquin one, p-dinitrobenzene, and m-dinitrobenzcne) in three solvents (acetonitrile, 1,4-dioxan and ethyl acetate). The extent of electron transfer during adsorption is understood from magnetic measurements and ESR spectral data. The corresponding data on mixed oxides of Pr and Al are reported for various compositions. The acid / base properties of these oxides are determined using a set of Hammett indicators. 展开更多
关键词 base PR and Its Mixtures with Alumina acid-base and Electron Donor properties of Pr6O
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Preparation of Fluorine-free MXene Ti_(3)C_(2)T_(x) and Its Electrical Properties 被引量:1
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作者 YAN Ming ZHANG Hao +3 位作者 DENG Yuxiao YANG Tianai HUANG Jiangtao ZHU Yu 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS CSCD 2023年第2期304-307,共4页
The fluorine-free MXene was prepared by Lewis acid salt etching of ternary layered ceramic MAX phase material.The structure of fluorine-free MXene was characterized by scanning electron microscopy(SEM)and X-ray diffra... The fluorine-free MXene was prepared by Lewis acid salt etching of ternary layered ceramic MAX phase material.The structure of fluorine-free MXene was characterized by scanning electron microscopy(SEM)and X-ray diffractometry(XRD).The study finds that the layer spacing of fluorine-free MXene is approximately twice that of MXene etched by the liquid-phase method,compared to the conventional liquidphase method.It also has greater capacitive properties.Therefore,the MXene prepared by this method shows a great potential for application in the field of capacitors. 展开更多
关键词 lewis acid fluorine-free MXene electrical properties
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Highly efficient catalyst for 1,1,2-trichloroethane dehydrochlorination via BN_(3) frustrated Lewis acid-base pairs
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作者 Yuxue Yue Fangmin Zuo +6 位作者 Bolin Wang Xiaoling Xian Jun Tang Haifeng Zhang Zilong Zhang Qingping Ke Wei Chen 《Nano Research》 SCIE EI CSCD 2024年第6期4773-4781,共9页
In this study,a novel non-metallic carbon-based catalyst co-doped with boron and nitrogen(B,N)was successfully synthesized.By precisely controlling the carbonization temperature of a binary mixed ionic liquid,we selec... In this study,a novel non-metallic carbon-based catalyst co-doped with boron and nitrogen(B,N)was successfully synthesized.By precisely controlling the carbonization temperature of a binary mixed ionic liquid,we selectively modified the doping site structure,ultimately constructing a B,N co-doped frustrated Lewis acid-base pair catalyst.This catalyst exhibited remarkable catalytic activity,selectivity,and stability in the dehydrochlorination reaction of 1,1,2-trichloroethane(TCE).Detailed characterization and theoretical calculations revealed that the primary active center of this catalyst was the BN_(3)configuration.Compared to conventional graphitic N structures,the BN_(3)structure had a higher p-band center,ensuring superior adsorption and activation capabilities for TCE during the reaction.Within the BN_(3)site,three negatively charged nitrogen atoms acted as Lewis bases,while positively charged boron atoms acted as Lewis acids.This synergistic interaction facilitated the specific dissociation of chlorine and hydrogen atoms from TCE,significantly enhancing the 1,1-dichloroethene selectivity.Through this research,we not only explored the active site structure and catalytic mechanism of B,N co-doped catalysts in depth but also provided an efficient,selective,and stable catalyst for the dehydrochlorination of TCE,contributing significantly to the development of non-metallic catalysts. 展开更多
关键词 B N co-doped sites DEHYDROCHLORINATION frustrated lewis acid-base pairs catalytic mechanism
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Efficient nitrite-to-ammonia electroreduction over Zr-Ni frustrated Lewis acid-base pairs
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作者 Ying Zhang Zhuohang Li +2 位作者 Wenyu Du Kai Chen Ke Chu 《Science China Chemistry》 SCIE EI CAS CSCD 2024年第5期1707-1714,共8页
Electrochemical NO_(2)~--to-NH_(3) conversion(NO_(2)RR) offers a green route to NH_(3) electrosynthesis, while developing efficient NO_(2)RR catalysis systems at high current densities remains a grand challenge. Herei... Electrochemical NO_(2)~--to-NH_(3) conversion(NO_(2)RR) offers a green route to NH_(3) electrosynthesis, while developing efficient NO_(2)RR catalysis systems at high current densities remains a grand challenge. Herein, we report an efficient Zr-NiO catalyst with atomically dispersed Zr-dopants incorporated in NiO lattice, delivering the exceptional NO_(2)RR performance with industriallevel current density(>0.2 A cm^(-2)). In situ spectroscopic measurements and theoretical simulations reveal the construction of ZrNi frustrated Lewis acid-base pairs(FLPs) on Zr-Ni O, which can substantially increase the number of absorbed nitrite(NO_(2)~-),promote the activation and protonation of NO_(2)~- and concurrently hamper the H coverage, boosting the activity and selectivity of Zr-NiO towards the NO_(2)RR. Remarkably, Zr-NiO exhibits the exceptional performance in a flow cell with high Faradaic efficiency for NH_(3) of 94.0% and NH_(3)yield rate of 1,394.1 μmol h^(-1)cm^(-2) at an industrial-level current density of 228.2 m A cm^(-2),placing it among the best NO_(2)RR electrocatalysts for NH_(3) production. 展开更多
关键词 electrochemical nitrite-to-ammonia conversion frustrated lewis acid-base pairs(FLPs) in situ spectroscopy theoretical computations
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人参药性菌质对小鼠Lewis肺癌的作用 被引量:4
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作者 朱凯 贾艾玲 +1 位作者 徐瑶 邱智东 《中国老年学杂志》 CAS CSCD 北大核心 2013年第23期5882-5883,共2页
目的观察人参药性菌质对小鼠Lewis肺癌的抑制作用并初步评价其一般毒性及对免疫功能的影响。方法将Lewis肺癌小鼠随机分为模型对照组、顺铂组、参一胶囊组、人参药性菌质低、中、高(2、4、8 g/kg)剂量组,每组12只,另取12只健康小鼠做为... 目的观察人参药性菌质对小鼠Lewis肺癌的抑制作用并初步评价其一般毒性及对免疫功能的影响。方法将Lewis肺癌小鼠随机分为模型对照组、顺铂组、参一胶囊组、人参药性菌质低、中、高(2、4、8 g/kg)剂量组,每组12只,另取12只健康小鼠做为空白对照组,给药后26 d取小鼠肿瘤、胸腺、脾脏、肝脏等脏器称重,检测脾脏CD4/CD8比值,检测脾脏杀伤性T细胞(CTL)的产生情况。结果与模型对照组比较,人参药性菌质各剂量组均可抑制肿瘤LLC成瘤(P<0.05或P<0.01);与空白对照组比较,人参药性菌质各组脾脏指数及胸腺指数无明显差异;与模型对照组比较,人参药性菌质各剂量组的CD4和CD8细胞百分比明显升高(P<0.05或P<0.01);与模型对照组比较,人参药性菌质各组CD4/CD8比值降低(P<0.05);与模型对照组比较,人参药性菌质各剂量组CTL数量及IFN-gamma细胞数增多(P<0.05或P<0.01)。结论人参药性菌质在体内有抗小鼠LLC成瘤的作用,无肝脏、胸腺、脾脏毒性;并且能够调节CD4/CD8比值,增加CTL细胞产生及IFN-γ细胞数,具有增强机体免疫功能的作用。 展开更多
关键词 人参 药性菌质 lewis肺癌 免疫功能
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Effect of x-alumina addition on H_2S oxidation properties of pure and modified y-alumina
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作者 Svetlana A.Yashnik Vadim V.Kuznetsov Zinfer R.Ismagilov 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2018年第2期258-274,共17页
The influence of the textural and acidic properties ofγ‐Al2O3,(γ+χ)‐Al2O3,and?‐Al2O3on the catalytic activity,selectivity,and stability of direct H2S oxidation has been studied.A comparison of the H2S‐to‐S con... The influence of the textural and acidic properties ofγ‐Al2O3,(γ+χ)‐Al2O3,and?‐Al2O3on the catalytic activity,selectivity,and stability of direct H2S oxidation has been studied.A comparison of the H2S‐to‐S conversion effectiveness of aluminas with their acidic properties(identified by Fourier transform infrared spectroscopy and temperature programmed desorption of NH3)shows that H2S adsorption occurs predominantly on weak Lewis acid sites(LAS).γ‐Alumina samples containing aχ‐phase and/or modified Mg2+ions have a greater concentration of weak LAS and exhibit greater catalytic activity.When alumina is treated with a sulfuric acid solution,strong LAS appear and the number of LAS decreases significantly.Modification of alumina with hydrochloric acid has a limited effect on LAS strength.Weak LAS are retained and double in number compared to that present in the unmodified alumina,but the treated sample has Al?Cl bonds.Alumina samples modified by sulfate and chloride anions exhibit poor catalytic activity in H2S oxidation. 展开更多
关键词 ALUMINA χ‐Al2O3 Hydrogen sulfide oxidation Acidic property lewis acid sites Fourier transform infrared spectroscopy NH3‐temperature programmed desorption
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Synergistic Lewis acid-base sites of ultrathin porous Co_(3)O_(4)nanosheets with enhanced peroxidase-like activity 被引量:3
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作者 Wenhui Lu Ming Yuan +6 位作者 Jing Chen Jiaxin Zhang Lingshuai Kong Zhenyu Feng Xicheng Ma Jie Su Jinhua Zhan 《Nano Research》 SCIE EI CSCD 2021年第10期3514-3522,共9页
Surface Lewis acid-base sites in crystal structure may influence the physicochemical properties and the catalytic performances in nanozymes.Understanding the synergistic effect mechanism of Co_(3)O_(4)nanozymes toward... Surface Lewis acid-base sites in crystal structure may influence the physicochemical properties and the catalytic performances in nanozymes.Understanding the synergistic effect mechanism of Co_(3)O_(4)nanozymes towards substances(3,3’,5,5’-tetramethylbenzidine(TMB)and hydrogen peroxide(H2O2))induced by surface Lewis acid-base sites is important to enhance the efficiency for peroxidase-like reaction.Herein,ultrathin porous Co_(3)O_(4)nanosheets with abundant Lewis acid-base sites were prepared by sodium borohydride(NaBH4)reduction treatment,which exhibited high-efficiency peroxidase-like activity compared with original Co_(3)O_(4)nanosheets.The Lewis acid-base sites for ultrathin porous Co_(3)O_(4)nanosheets nanozyme were owing to the coordination unsaturation of Co ions and the formation of defect structure.Ultrathin porous Co_(3)O_(4)nanosheets had 18.26-fold higher catalytic efficiency(1.27×10^(-2)s^(-1)·mM^(-1))than that of original Co_(3)O_(4)(6.95×10^(-4)s^(-1)·mM^(-1))in oxidizing TMB substrate.The synergistic effect of surface acid and base sites can enhance the interfacial electron transfer process of Co_(3)O_(4)nanosheets,which can be a favor of absorption substrates and the generation of reactive intermediates such as radicals.Furthermore,the limit of detection of hydroquinol was 0.58μM for ultrathin porous Co_(3)O_(4)nanosheets,965-fold lower than original Co_(3)O_(4)(560μM).Besides,the linear range of ultrathin porous Co_(3)O_(4)nanosheets was widely with the concentration of 5.0-1,000μM.Colorimetric detection of hydroquinol by agarose-based hydrogel membrane was provided based on excellent peroxidase-like properties.This study provided insights into designing high-performance nanozymes for peroxidase-like catalysis via a strategy of solid surface acid-base sites engineering. 展开更多
关键词 cobalt oxide nanozyme lewis acid-base sites peroxidase-like colorimetric sensor hydroquinol
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Recent advances in selective C–C bond coupling for ethanol upgrading over balanced Lewis acid-base catalysts 被引量:1
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作者 Jingjing Dai Hongbo Zhang 《Science China Materials》 SCIE EI CSCD 2019年第11期1642-1654,共13页
Ethanol is a considerable platform molecule in biomass conversion,which could be acquired in quantity through acetone-butanol-ethanol(ABE)fermentation.People have been working on the upgrading of ethanol to value adde... Ethanol is a considerable platform molecule in biomass conversion,which could be acquired in quantity through acetone-butanol-ethanol(ABE)fermentation.People have been working on the upgrading of ethanol to value added chemicals for decades.In the meantime,1-butanol and a series of value added products have been selectively generated through C–C bond coupling.In this mini-review,we focus on the recent advances in selective C–C bond formation over balanced Lewis acid-base catalysts such as modified metal oxide,mixed metal oxide,hydroxyapatite and zeolite confined transition metal oxide catalysts.Among them,Pd-MgAlO_x and Sr-based hydroxyapatite exhibit>70%1-butanol selectivity,while Zn——xZr_yO_z and Ta-Si BEA zeolite achieve>80%of isobutene and butadiene selectivity respectively.The mechanism and reaction pathway of C–C bond formation in each reaction system are described in detail.The correlation between C–C bond coupling and the acidity/basicity of the Lewis acid-base pairs from the surface of the catalysts are also discussed. 展开更多
关键词 BALANCED lewis acid-base pair ALDOL condensation ETHANOL UPGRADING C–C bond formation metal oxide
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Writing and Erasing Encryption Information Based on Frustrated Lewis Pair Chemistry
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作者 Hui Fang Xiao Long +2 位作者 Xia Lan Bao-Yi Ren Guohua Xie 《Precision Chemistry》 2023年第7期418-422,共5页
Lewis acid−base adducts resulting from instantaneous interactions provide a cost-effective strategy for color tuning and anticounterfeiting information.Herein,we report the construction of luminescent Lewis acid−base ... Lewis acid−base adducts resulting from instantaneous interactions provide a cost-effective strategy for color tuning and anticounterfeiting information.Herein,we report the construction of luminescent Lewis acid−base adducts via inkjet printing.Due to the unique weak coordination bond of B→N,it is feasible to construct anticounterfeiting information that is easy to erase.The in situ postsynthesis of the luminescent quick response codes via inkjet printing facilitates precision chemistry control to change the emission ranging from deep-blue(peaking at 407 nm)to orange-red(peaking at 597 nm).The encrypted information can be quickly erased either by modulating the temperature to dissociate the weak coordination or strong Lewis base to promote a neutralization reaction. 展开更多
关键词 weak coordination bond lewis acid-base adducts inkjet printing luminescence anticounterfeit
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硼酸三甲酯为探针红外光谱定量研究氧化镁的路易斯碱性 被引量:2
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作者 傅仕福 廖力夫 +4 位作者 汪敏 梁俊 李灿 张慧 辛勤 《光谱实验室》 CAS CSCD 2005年第6期1168-1171,共4页
采用硼酸三甲酯(BATE)作为探针分子对MgO的路易斯碱性进行了红外光谱定量研究。MgO对硼酸三甲酯的吸附使硼酸三甲酯在1360cm-1的谱峰分裂成1410cm-1和1300cm-1两个峰,1036cm-1的谱峰紫移到1060cm-1。低压下吸收峰高与硼酸三甲酯压力成正... 采用硼酸三甲酯(BATE)作为探针分子对MgO的路易斯碱性进行了红外光谱定量研究。MgO对硼酸三甲酯的吸附使硼酸三甲酯在1360cm-1的谱峰分裂成1410cm-1和1300cm-1两个峰,1036cm-1的谱峰紫移到1060cm-1。低压下吸收峰高与硼酸三甲酯压力成正比,与MgO含量成正比。结果表明MgO有一定的路易斯碱强度,与硼酸三甲酯之间的吸附是单分子层化学吸附。 展开更多
关键词 MGO 硼酸三甲酯 路易斯碱性 红外光谱
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具有键合功能热塑性聚氨酯的表面性能 被引量:3
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作者 张文雨 李晋庆 罗运军 《高分子材料科学与工程》 EI CAS CSCD 北大核心 2012年第2期28-31,共4页
通过反相气相色谱法(IGC),采用非极性和极性探针分子研究了新型热塑性聚氨酯弹性体(DTPU)的色散表面自由能和表面Lewis酸碱性质,并与传统的推进剂用热塑性聚氨酯粘合剂(BTPU)做了对比。结果表明,DTPU与BTPU的色散表面自由能较为接近,并... 通过反相气相色谱法(IGC),采用非极性和极性探针分子研究了新型热塑性聚氨酯弹性体(DTPU)的色散表面自由能和表面Lewis酸碱性质,并与传统的推进剂用热塑性聚氨酯粘合剂(BTPU)做了对比。结果表明,DTPU与BTPU的色散表面自由能较为接近,并且随着温度的升高而线性降低;DTPU的酸常数Ka和碱常数Kb分别为0.09和0.48,而BTPU的酸常数Ka和碱常数Kb分别为0.06和0.37,DTPU的酸性和表面总的酸碱作用能力较大,与推进剂中高能固体填料具有更好的相互作用。 展开更多
关键词 反相气相色谱法 热塑性聚氨酯 表面自由能 酸碱性质
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反相气相色谱法表征1-烯丙基-3-甲基氯代咪唑离子液体的表面性质 被引量:2
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作者 陈亚丽 王强 +2 位作者 邓丽霜 张正方 唐军 《色谱》 CAS CSCD 北大核心 2013年第2期147-150,共4页
采用反相气相色谱(IGC)技术研究了不同温度下1-烯丙基-3-甲基氯代咪唑([AMIM]Cl)的表面性质。以正己烷、正庚烷、正辛烷和正壬烷作为非极性探针分子测定[AMIM]Cl在343.15、353.15、363.15和373.15 K温度下的表面色散自由能;以二氯甲烷... 采用反相气相色谱(IGC)技术研究了不同温度下1-烯丙基-3-甲基氯代咪唑([AMIM]Cl)的表面性质。以正己烷、正庚烷、正辛烷和正壬烷作为非极性探针分子测定[AMIM]Cl在343.15、353.15、363.15和373.15 K温度下的表面色散自由能;以二氯甲烷、三氯甲烷、丙酮、乙酸乙酯、四氢呋喃作为极性探针分子测定离子液体Lewis酸碱性质,并测定了吸附自由能和吸附自由焓变等热动力学参数。实验结果表明,[AMIM]Cl的酸解离平衡常数Ka为0.34,碱解离平衡常数Kb为1.68,其表面呈Lewis两性偏碱性特点。在343.15、353.15、363.15和373.15 K温度下,[AMIM]Cl的表面色散自由能分别为52.26、50.82、46.08和42.05 mJ/m2。这一结果对研究离子液体的表面性质及应用有指导作用。 展开更多
关键词 反相气相色谱 1-烯丙基-3-甲基氯代咪唑 离子液体 表面性质 表面色散自由能 lewis酸碱参数
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中国土地制度改革问题的探讨 被引量:3
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作者 王文龙 《云南财经大学学报》 CSSCI 北大核心 2012年第2期26-31,共6页
随着城市化的不断推进、刘易斯拐点的到来,传统劳动密集型的小农生产模式显然难以持续,也阻碍了农业的规模化、产业化经营,导致粮食安全问题日趋严峻。落后的土地产权制度不仅为地方政府的参,地寻租提供了各种机会,造成了大量失地... 随着城市化的不断推进、刘易斯拐点的到来,传统劳动密集型的小农生产模式显然难以持续,也阻碍了农业的规模化、产业化经营,导致粮食安全问题日趋严峻。落后的土地产权制度不仅为地方政府的参,地寻租提供了各种机会,造成了大量失地农民,激化了社会矛盾,也导致土地的高度垄断,住房价格的畸高,严重阻碍城市化的进程,二者都严重影响到中国社会的稳定。只有尽快进行合理的土地制度改革,才能加速土地的规模化、产业化经营,解决粮食安全问题,并大幅降低住房价格,保护农民权益,促进城市化的良性发展,从根源上缓解社会危机,为中国经济的可持续发展奠定坚实基础。 展开更多
关键词 刘易斯拐点 土地产权 私有化 粮食安全 城市化
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以硼酸三甲酯为探针分子红外光谱法测定Al_2O_3、SiO_2的路易斯碱性的研究 被引量:2
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作者 傅仕福 廖力夫 +4 位作者 吕昌银 汪敏 李灿 辛勤 张慧 《南华大学学报(自然科学版)》 2004年第3期56-58,共3页
以硼酸三甲酯为探针分子对金属氧化物Al2O3和非金属氧化物SiO2的表面路易斯碱性进行了红外光谱研究.硼酸三甲酯可灵敏地与Al2O3和SiO2的表面路易斯碱中心作用,其红外光谱提供了Al2O3和SiO2的表面路易斯碱性强度的直接信息.
关键词 硼酸三甲酯 探针分子 红外光谱法 氧化铝 氧化硅 路易斯碱性 测定方法
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固体火箭高温高压复杂燃气系统的扩散系数及其相似准则数计算
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作者 陈军 《弹道学报》 CSCD 北大核心 2022年第4期52-60,97,共10页
为了解决固体火箭推进剂高温高压燃气输运系数难以实验测量和理论预估的实际问题,考虑燃气中含有H_(2)O、HCl、SO_(2)等强极性组分和H_(2)等轻质组分,通过大量文献实例验证,归纳了适于上述组分及其混合物在高温高压条件下的扩散系数计... 为了解决固体火箭推进剂高温高压燃气输运系数难以实验测量和理论预估的实际问题,考虑燃气中含有H_(2)O、HCl、SO_(2)等强极性组分和H_(2)等轻质组分,通过大量文献实例验证,归纳了适于上述组分及其混合物在高温高压条件下的扩散系数计算方法,并计算了典型双基推进剂、复合改性双基推进剂和复合推进剂三种主要固体推进剂燃气在不同温度(1500~3800 K)和压强(8~20 MPa)下的扩散系数和输运准则数(施密特数和路易斯数),得到了固体火箭发动机燃气扩散系数随温度和压强变化的幂指数函数规律(典型双基推进剂燃气的扩散系数随温度变化的幂指数为1.64655、典型复合改性双基推进剂和典型复合推进剂为1.62952),以及路易斯数、施密特数的典型取值(典型双基推进剂燃气的施密特数为0.772、路易斯数为0.91,典型复合改性双基推进剂燃气的施密特数为0.675、路易斯数为0.9,典型复合推进剂燃气的施密特数为0.74、路易斯数为0.83)。这对于促进高温高压气体混合物输运性质的深入研究、火箭发动机燃烧及其内外流动仿真,均具有重要的实际应用意义。该方法没有考虑凝聚相对输运性质的影响。 展开更多
关键词 固体火箭 输运系数 扩散系数 施密特数 路易斯数 固体推进剂
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用硼酸三甲酯对Al_2O_3路易斯碱性进行红外光谱定量研究
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作者 傅仕福 廖力夫 +5 位作者 陈仲清 王丽华 汪敏 李灿 辛勤 张慧 《南华大学学报(自然科学版)》 2005年第2期32-35,共4页
采用硼酸三甲酯作为探针分子对Al2O3的路易斯碱性进行了红外光谱定量研究.Al2O3对硼酸三甲酯的吸附使硼酸三甲酯在1360cm-1的谱峰分裂成1409cm-1和1287cm-1两个峰,1036cm-1的谱峰紫移到1067cm-1.低压下吸收峰高与硼酸三甲酯压力成正比,... 采用硼酸三甲酯作为探针分子对Al2O3的路易斯碱性进行了红外光谱定量研究.Al2O3对硼酸三甲酯的吸附使硼酸三甲酯在1360cm-1的谱峰分裂成1409cm-1和1287cm-1两个峰,1036cm-1的谱峰紫移到1067cm-1.低压下吸收峰高与硼酸三甲酯压力成正比,与Al2O3含量成正比.结果表明Al2O3有一定的路易斯碱强度,与硼酸三甲酯之间的吸附是单分子层化学吸附. 展开更多
关键词 AL2O3 硼酸三甲酯 路易斯碱性 红外光谱
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氧化铈酸碱催化有机官能团化反应研究进展 被引量:1
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作者 焦东霞 王业红 +2 位作者 张志鑫 雷丽军 王峰 《陕西师范大学学报(自然科学版)》 CAS CSCD 北大核心 2022年第2期86-92,F0002,共8页
氧化铈具有独特的储放氧能力,在传统反应中常作为典型的氧化还原催化剂用于高效催化汽车尾气及水汽变换等反应。此外,氧化铈基催化剂的酸碱性质与其独特的缺陷性质密不可分,且在一定程度上具有可调控性,其酸碱催化有机官能团化反应近年... 氧化铈具有独特的储放氧能力,在传统反应中常作为典型的氧化还原催化剂用于高效催化汽车尾气及水汽变换等反应。此外,氧化铈基催化剂的酸碱性质与其独特的缺陷性质密不可分,且在一定程度上具有可调控性,其酸碱催化有机官能团化反应近年来备受关注。基于此,综述了氧化铈基催化剂酸碱性质调控的有效方法以及氧化铈在酸碱催化有机官能团化反应中的应用。具体以醇脱水,醚、酯、腈等的水解,酸、酯的酮基化,Aldol缩合以及Prins缩合等反应为例,详细介绍了氧化铈酸碱催化性能的研究现状,并提出了氧化铈酸碱催化领域面临的困难与挑战,展望了未来该领域的研究方向和前景,以期拓宽传统酸碱催化体系的边界,为发展绿色、高效有机合成路径创造更多的可能性。 展开更多
关键词 氧化铈 lewis酸碱性 缺陷调控 官能团化反应
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软硬酸碱理论经验规则的原因探讨 被引量:1
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作者 赵苹苹 胡锴 +1 位作者 蔡苹 程功臻 《大学化学》 CAS 2022年第11期216-218,共3页
软硬酸碱规则是Lewis酸碱理论的重要组成部分,目前主要依赖经验描述。本文通过大学本科学生熟知的分子轨道理论对“硬亲硬、软亲软”经验规则背后的原因进行分析,发现“硬亲硬、软亲软”分别对应于离子键和共价键,并用实例说明该方法可... 软硬酸碱规则是Lewis酸碱理论的重要组成部分,目前主要依赖经验描述。本文通过大学本科学生熟知的分子轨道理论对“硬亲硬、软亲软”经验规则背后的原因进行分析,发现“硬亲硬、软亲软”分别对应于离子键和共价键,并用实例说明该方法可以解释无机物的结构和性质。 展开更多
关键词 电子酸碱 软硬酸碱 分子轨道理论 前线轨道 结构和性质
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