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甲醇合成催化剂Cu/CeO2活性位的形成机制与初始催化机理探索 预览
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作者 郭艳青 李红耀 《云南化工》 CAS 2020年第3期129-130,共2页
结合甲醇合成催化剂在制备过程中和反应初期得到的表征信息(XRF、XRD、HRTEM、H2-TPR等),对催化剂Cu/CeO2活性位的形成机制与初始催化机理进行了探索。结果表明,催化剂Cu/CeO2制备过程中,除了CuO被完全还原外,载体CeO2的表面也有部分被... 结合甲醇合成催化剂在制备过程中和反应初期得到的表征信息(XRF、XRD、HRTEM、H2-TPR等),对催化剂Cu/CeO2活性位的形成机制与初始催化机理进行了探索。结果表明,催化剂Cu/CeO2制备过程中,除了CuO被完全还原外,载体CeO2的表面也有部分被还原;CO/H2在Cu/CeO2上合成甲醇之前,会有短暂的CO2生成,当CO2生成达到峰值时,甲醇合成活性开始出现。 展开更多
关键词 甲醇合成催化剂 前驱体 形成机制 初始催化性能
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Effects of cerium precursors on surface properties of mesoporous CeMnOx catalysts for toluene combustion
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作者 Changyu Zhang Wei Chu +3 位作者 Feng Chen Lei Li Ruiyu Jiang Jinlong Yan 《中国稀土学报:英文版》 SCIE EI CAS CSCD 2020年第1期70-75,共6页
Mesoporous CeMnOx composite oxides catalysts were prepared by surfactant-assisted co-precipitation method and used for the catalytic oxidation of toluene.The effect of different cerium precursors[Ce(NO3)3 and(NH4)2 Ce... Mesoporous CeMnOx composite oxides catalysts were prepared by surfactant-assisted co-precipitation method and used for the catalytic oxidation of toluene.The effect of different cerium precursors[Ce(NO3)3 and(NH4)2 Ce(NO3)6] on catalyst structure,surface properties and toluene combustion activities of mesoporous CeMnOx catalysts were investigated.The Ce(Ⅲ)MnOx catalyst prepared from Ce(NO3)3 precursor shows higher catalytic activity,with a 90% conversion temperature of 240℃,which is better than the Ce(Ⅳ)MnOx catalyst derived from[(NH4)2 Ce(NO3)6] precursor.On the basis of characterizations,it reveals that abundant surface content of Mn4+,better redox behavior and larger concentration of surface active oxygen species are responsible for the excellent catalytic performance. 展开更多
关键词 Cerium precursor CeMnOx composite catalyst Synergistic effect Catalytic combustion TOLUENE Rare earths
甲羟戊酸途径的代谢支路调控策略的研究进展 预览
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作者 徐镇祥 李美洁 +4 位作者 门潇 陈国强 王纪明 咸漠 张海波 《生物加工过程》 CAS 2020年第1期44-51,共8页
萜类化合物作为一大类重要天然产物,在食品、化工、医药和能源等领域广泛应用。微生物法合成萜类化合物因具有生产周期较短、可规模化生产等优点,是目前研究的热点。但是生产效率低严重制约着微生物法合成萜类化合物的工业化发展,而代... 萜类化合物作为一大类重要天然产物,在食品、化工、医药和能源等领域广泛应用。微生物法合成萜类化合物因具有生产周期较短、可规模化生产等优点,是目前研究的热点。但是生产效率低严重制约着微生物法合成萜类化合物的工业化发展,而代谢调控是解决上述问题的主要有效手段之一。目前,多数学者集中于主路径的代谢调控研究,忽略了对于萜类化合物的生产至关重要的支路径。本文中,笔者围绕支路径调控直接相关的前体物质供应和辅助因子的协调、竞争途径的调控以及间接对代谢调控产生影响的宿主体的进化三个方面,综述萜类化合物甲羟戊酸途径的代谢途径支路调控策略研究进展,并对代谢路径支路调控的发展方向做进一步展望。 展开更多
关键词 甲羟戊酸 代谢支路 前体物质 辅助因子 阻断竞争途径 宿主体进化 萜类化合物 代谢调控
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Early active immunization with Aβ3–10-KLH vaccine reduces tau phosphorylation in the hippocampus and protects cognition of mice 预览
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作者 Jin-Chun Wang Kun Zhu +3 位作者 Hui-Yi Zhang Guo-Qing Wang Hui-Ying Liu Yun-Peng Cao 《中国神经再生研究:英文版》 SCIE CAS CSCD 2020年第3期519-527,共9页
Active and passive anti-Aβimmunotherapies have successfully been used for the prevention and treatment of Alzheimer’s disease animal models.However,clinical use of these immunotherapies is not effective,because the ... Active and passive anti-Aβimmunotherapies have successfully been used for the prevention and treatment of Alzheimer’s disease animal models.However,clinical use of these immunotherapies is not effective,because the vaccination is administered too late.At 1 month of age,100μL of Aβ3–10-KLH peptide(vaccine,2μg/μL)was subcutaneously injected into the neck of an amyloid precursor protein/presenilin-1/tau transgenic(3×Tg-AD)mouse model.Aβ3–10-KLH peptide was re-injected at 1.5,2.5,3.5,4.5,5.5,and 6.5 months of age.Serum levels of Aβantibody were detected by enzyme-linked immunosorbent assay,while spatial learning and memory ability were evaluated by Morris water maze.Immunohistochemistry was used to detect total tau with HT7 and phosphorylated tau with AT8(phosphorylation sites Ser202 and Thr205)and AT180(phosphorylation site Thr231)antibodies in the hippocampus.In addition,western blot analysis was used to quantify AT8 and AT180 expression in the hippocampus.The results showed that after vaccine injection,mice produced high levels of Aβantibody,cognitive function was significantly improved,and total tau and phosphorylated tau levels were significantly reduced.These findings suggest that early active immunization with Aβ3–10-KLH vaccine can greatly reduce tau phosphorylation,thereby mitigating the cognitive decline of 3×Tg-AD mice.This study was approved by the Animal Ethics Committee of China Medical University,China(approval No.103-316)on April 2,2016. 展开更多
关键词 3×Tg-AD Aβ3–10-KLH VACCINE Alzheimer’s disease amyloid precursor protein AMYLOID-BETA cognitive DECLINE tau phosphorylation transgenic mouse
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Differential expression of glial cell line-derived neurotrophic factor splice variants in the mouse brain 预览
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作者 Xiao-He Gu Heng Li +4 位作者 Lin Zhang Tao He Xiang Chai He Wei Dian-Shuai Gao 《中国神经再生研究:英文版》 SCIE CAS CSCD 2020年第2期270-276,共7页
Glial cell line-derived neurotrophic factor(GDNF) plays a critical role in neuronal survival and function. GDNF has two major splice variants in the brain,α-pro-GDNF and β-pro-GDNF, and both isoforms have strong neu... Glial cell line-derived neurotrophic factor(GDNF) plays a critical role in neuronal survival and function. GDNF has two major splice variants in the brain,α-pro-GDNF and β-pro-GDNF, and both isoforms have strong neuroprotective effects on dopamine neurons. However, the expression of the GDNF splice variants in dopaminergic neurons in the brain remains unclear. Therefore, in this study, we investigated the mRNA and protein expression of α-and β-pro-GDNF in the mouse brain by real-time quantitative polymerase chain reaction, using splice variant-specific primers, and western blot analysis. At the mRNA level,β-pro-GDNF expression was significantly greater than that of α-pro-GDNF in the mouse brain. In contrast, at the protein level,α-pro-GDNF expression was markedly greater than that of β-pro-GDNF. To clarify the mechanism underlying this inverse relationship in mRNA and protein expression levels of the GDNF splice variants, we analyzed the expression of sorting protein-related receptor with A-type repeats(SorLA) by real-time quantitative polymerase chain reaction. At the mRNA level, SorLA was positively associated with β-pro-GDNF expression, but not with α-pro-GDNF expression. This suggests that the differential expression of α-and β-pro-GDNF in the mouse brain is related to SorLA expression. As a sorting protein, SorLA could contribute to the inverse relationship among the mRNA and protein levels of the GDNF isoforms. This study was approved by the Animal Ethics Committee of Xuzhou Medical University, China on July 14, 2016. 展开更多
关键词 Δ78 locus BRAIN region dopaminergic neurons glial cell line-derived NEUROTROPHIC factor mouse BRAIN precursor protein α-pro-GDNF β-pro-GDNF sorting protein-related receptor with A-TYPE REPEATS splice variants
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SiO2气凝胶的疏水改性及性能研究进展
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作者 张明 《现代化工》 CAS CSCD 北大核心 2020年第1期58-62,共5页
从原位共聚和后处理两个方面着手,介绍了近年来国内外硅气凝胶疏水改性的研究进展;再从疏水SiO2气凝胶的特殊性能出发,简要介绍了其在隔热、催化、吸附等技术领域的研究进展。
关键词 SIO2气凝胶 前驱体 疏水改性 接触角 隔热 吸附
δ-Opioid receptor as a potential therapeutic target for ischemic stroke 预览
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作者 Kalpana Subedi Hongmin Wang 《中国神经再生研究:英文版》 SCIE CAS CSCD 2020年第1期20-24,共5页
Ischemic stroke is a global epidemic condition due to an inadequate supply of blood and oxygen to a specific area of brain either by arterial blockage or by narrowing of blood vessels.Despite having advancement in the... Ischemic stroke is a global epidemic condition due to an inadequate supply of blood and oxygen to a specific area of brain either by arterial blockage or by narrowing of blood vessels.Despite having advancement in the use of thrombolytic and clot removal medicine,significant numbers of stroke patients are still left out without option for treatment.In this review,we summarize recent research work on the activation ofδ-opioid receptor as a strategy for treating ischemic stroke-caused neuronal injury.Moreover,as activation ofδ-opioid receptor by a non-peptidicδ-opioid receptor agonist also modulates the expression,maturation and processing of amyloid precursor protein andβ-secretase activity,the potential role of these effects on ischemic stroke caused dementia or Alzheimer’s disease are also discussed. 展开更多
关键词 AGONIST AKT AMYLOID precursor protein BDNF ischemic stroke NEUROPROTECTION δ-opioid receptor p38 MAPK PI3K TRKB
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饮用水中卤代苯醌类新型消毒副产物研究进展 预览
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作者 王永京 曹康玲 +5 位作者 吕峥 张若琳 满涛 张明露 丁宁 任连海 《给水排水》 CSCD 北大核心 2020年第2期133-137,144,共6页
卤代苯醌(HBQs)是近年来饮用水中新检出的一类未受控消毒副产物,相比于三卤甲烷、卤乙酸等受控消毒副产物,其在水中的存在浓度更低,仅为ng/L水平,而细胞毒性和遗传毒性更强,同时具有生殖发育毒性。由于长期接触HBQs可能存在健康风险,综... 卤代苯醌(HBQs)是近年来饮用水中新检出的一类未受控消毒副产物,相比于三卤甲烷、卤乙酸等受控消毒副产物,其在水中的存在浓度更低,仅为ng/L水平,而细胞毒性和遗传毒性更强,同时具有生殖发育毒性。由于长期接触HBQs可能存在健康风险,综述了饮用水中目前HBQs的存在水平、前驱物、毒性及生成影响因素、控制与去除技术等进展,拟为将来对HBQs的深入研究提供支持,对其潜在健康风险的评估和饮用水卫生标准的制定提供科学依据。 展开更多
关键词 消毒副产物 卤代苯醌 毒性 前体物 控制与消除
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Proprotein convertase 1/3-mediated down-regulation of brain-derived neurotrophic factor in cortical neurons induced by oxygen-glucose deprivation 预览
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作者 Xiang-Yang Zhang Feng Liu +2 位作者 Yan Chen Wei-Chun Guo Zhao-Hui Zhang 《中国神经再生研究:英文版》 SCIE CAS CSCD 2020年第6期1066-1070,共5页
Brain-derived neurotrophic factor(BDNF)has robust effects on synaptogenesis,neuronal differentiation and synaptic transmission and plasticity.The maturation of BDNF is a complex process.Proprotein convertase 1/3(PC1/3... Brain-derived neurotrophic factor(BDNF)has robust effects on synaptogenesis,neuronal differentiation and synaptic transmission and plasticity.The maturation of BDNF is a complex process.Proprotein convertase 1/3(PC1/3)has a key role in the cleavage of protein precursors that are directed to regulated secretory pathways;however,it is not clear whether PC1/3 mediates the change in BDNF levels caused by ischemia.To clarify the role of PC1/3 in BDNF maturation in ischemic cortical neurons,primary cortical neurons from fetal rats were cultured in a humidified environment of 95%N_2 and 5%CO_2 in a glucose-free Dulbecco's modified Eagle's medium at 37℃for3 hours.Enzyme-linked immunosorbent assays and western blotting showed that after oxygen-glucose deprivation,the secreted and intracellular levels of BDNF were significantly reduced and the intracellular level of PC1/3 was decreased.Transient transfection of cortical neurons with a PC1/3 overexpression plasmid followed by oxygen-glucose deprivation resulted in increased PC1/3 levels and increased BDNF levels.When levels of the BDNF precursor protein were reduced,the concentration of BDNF in the culture medium was increased.These results indicate that PC 1/3 cleavage of BDNF is critical for the conversion of pro-BDNF in rat cortical neurons during ischemia.The study was approved by the Animal Ethics Committee of Wuhan University School of Basic Medical Sciences. 展开更多
关键词 cortical neuron ischemia NEUROTROPHIN oxygen-glucose deprivation precursor protein of BRAIN-DERIVED NEUROTROPHIC factor PROPROTEIN CONVERTASE PROPROTEIN CONVERTASE 1/3
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两性霉素B补料分批发酵工艺优化 预览
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作者 王昂 王耀耀 +3 位作者 仲伟潭 张雪霞 任志红 李敏 《化学与生物工程》 CAS 2020年第2期51-54,共4页
为大幅提高产两性霉素B菌株的发酵产抗水平,对外源性短链脂肪酸类前体物质及其添加时机、添加量进行优化,得到了两性霉素B补料分批发酵工艺,即在产两性霉素B菌株发酵培养24~56 h左右,一次性补入2~4 g·L^-1(以发酵液总量计)的丙酸... 为大幅提高产两性霉素B菌株的发酵产抗水平,对外源性短链脂肪酸类前体物质及其添加时机、添加量进行优化,得到了两性霉素B补料分批发酵工艺,即在产两性霉素B菌株发酵培养24~56 h左右,一次性补入2~4 g·L^-1(以发酵液总量计)的丙酸钠。该工艺解决了两性霉素B生物合成途径中内酯环形成的关键性因素,大幅提高了产两性霉素B菌株的发酵产抗水平。经15 t生产罐验证,最终实现了连续3批平均放罐效价达10977μg·mL^-1的发酵产抗水平,与采用原发酵工艺的生产罐批相比,放罐效价提高了39.4%。 展开更多
关键词 两性霉素B 前体物质 丙酸钠 补料分批发酵 放罐效价
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Synthesis via Precursor Method and Shape Evolution of Basic Magnesium Carbonate 预览
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作者 吴丹 钟云龙 +3 位作者 路绍琰 高春娟 王泽江 黄西平 《结构化学》 SCIE CAS CSCD 2020年第3期543-550,379,共9页
Basic magnesium carbonate(4 MgCO3·Mg(OH)2·4 H2 O) with spherical-like structure was synthesized through precursors thermal decomposition. The precursor of magnesium carbonate trihydrates(MgCO3·3 H2 O) w... Basic magnesium carbonate(4 MgCO3·Mg(OH)2·4 H2 O) with spherical-like structure was synthesized through precursors thermal decomposition. The precursor of magnesium carbonate trihydrates(MgCO3·3 H2 O) was synthesized by brine and ammonium bicarbonate, and the thermal decomposition conditions were investigated in detail. The obtained particulate was characterized using SEM, XRD and laser particle analyzer. The result showed that it was easy to obtain spherical-like 4 MgCO3·Mg(OH)2·4 H2 O by precursor thermal decomposition at 80~100 ℃ with thermal decomposition time 90 min, stirring time 15 min and the liquid initial concentration 0.1 mol/L, while rod-like 4 MgCO3·Mg(OH)2·4 H2 O with a surface of "house of card" structure was more likely to be obtained at low temperature(55 ℃), and rosette-like products were obtained at a little higher temperature(80 ℃) by direct synthesis. 展开更多
关键词 PRECURSOR basic magnesium carbonate thermal decomposition BRINE
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基于均相沉淀法制备高纯度球形钌粉 预览
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作者 裴洪营 赵家春 +3 位作者 吴跃东 保思敏 杨海琼 董海刚 《中南大学学报:自然科学版》 EI CAS CSCD 北大核心 2020年第2期294-300,共7页
针对高纯度球形钌粉制备技术难题,基于均相沉淀法制备高纯球形钌粉并分析其过程机理。研究结果表明:三氯化钌溶液经5级离子交换纯化处理后,以尿素为均相沉淀剂,控制钌的质量浓度为10 g/L、尿素与钌的物质的量比为6:1、反应温度为95℃、... 针对高纯度球形钌粉制备技术难题,基于均相沉淀法制备高纯球形钌粉并分析其过程机理。研究结果表明:三氯化钌溶液经5级离子交换纯化处理后,以尿素为均相沉淀剂,控制钌的质量浓度为10 g/L、尿素与钌的物质的量比为6:1、反应温度为95℃、反应时间为4 h,获得球形或类球形钌粉前驱体,经煅烧氢还原、混酸煮洗后,可获得纯度大于99.999%的球形或类球形钌粉。在均相沉淀过程中,尿素缓慢水解生成的OH-均匀分布在溶液中,与钌络合离子反应,生成球形钌粉前驱体,煅烧后得到球形钌粉。 展开更多
关键词 三氯化钌 离子交换 均相沉淀 前驱体 高纯球形钌粉
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Evolution of the deformation field and earthquake fracture precursors of strike-slip faults 预览
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作者 Qi Zhang YongHong Zhao +6 位作者 Hang Wang Muhammad Irfan Ehsan JiaYing Yang Gang Tian AnDong Xu Ru Liu YanJun Xiao 《地球与行星物理:英文版》 CSCD 2020年第2期151-162,共12页
Seismic hazard analysis is gaining increased attention in the present era because of the catastrophic effects of earthquakes.Scientists always have as a goal to develop new techniques that will help forecast earthquak... Seismic hazard analysis is gaining increased attention in the present era because of the catastrophic effects of earthquakes.Scientists always have as a goal to develop new techniques that will help forecast earthquakes before their reoccurrence. In this research,we have performed a shear failure experiment on rock samples with prefabricated cracks to simulate the process of plate movement that forms strike-slip faults. We studied the evolution law of the deformation field to simulate the shear failure experiment, and these results gave us a comprehensive understanding of the elaborate strain distribution law and its formation process with which to identify actual fault zones. We performed uniaxial compression tests on marble slabs with prefabricated double shear cracks to study the distribution and evolution of the deformation field during shear failure. Analysis of the strain field at different loading stages showed that with an increase in the load, the shear strain field initially changed to a disordered-style distribution. Further, the strain field was partially concentrated and finally completely concentrated near the crack and then distributed in the shape of a strip along the crack. We also computed coefficients of variation(CVs) for the physical quantities u, v, and exy, which varied with the load. The CV curves were found to correspond to the different loading stages. We found that at the uniform deformation stage, the CV value was small and changed slowly,whereas at the later nonuniform deformation stage, the CV value increased sharply and changed abruptly. Therefore, the precursor to a rock sample breakdown can be predicted by observing the variation characteristics of CV statistics. The correlation we found between our experimental and theoretical results revealed that our crack evolution and sample deformation results showed good coupling with seismic distribution characteristics near the San Andreas Fault. 展开更多
关键词 strike-slip fracture digital image correlation method evolution of deformation field rock failure fracture precursor
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Identification and quantification of benzimidazole metabolites of thiophonate-methyl sprayed on celery cabbage using SiO_2@NiO solid-phase extraction in combination with HPLC-MS/MS
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作者 Qiongwei Yu Shijie Liu +3 位作者 Feng Zheng Huaming Xiao Hongyan Guan Yuqi Feng 《中国化学快报:英文版》 SCIE CAS CSCD 2020年第2期482-486,共5页
Thiophonate-methyl(TPM) is one of fungicides and pesticides widely used in agriculture field.However,the residue of its benzimidazole(BZD) metabolites in related agricultural products poses a potential risk to consume... Thiophonate-methyl(TPM) is one of fungicides and pesticides widely used in agriculture field.However,the residue of its benzimidazole(BZD) metabolites in related agricultural products poses a potential risk to consumers.In this paper,nickel oxide nanoparticle-deposited silica(SiO_2@NiO) composite was used for the selective enrichment and purification of TPM's BZD metabolites in celery cabbage sprayed with TPM.Meanwhile,high-performance liquid chromatography coupled with precursor ion scan-mass spectrometry(HPLC-PIS-MS) and high-resolution MS/MS analysis(HR-MS/MS) was utilized for their qualitative and quantitative analysis.Twenty-one potential TPM's BZD metabolites were found and four of them were identified.One metabolite was discovered for the first time.Besides,a robust and sensitive quantitative method was developed with good linearities(R^2> 0.9972) within a wide range of 10.00-1000 ng/g.The detection limits of three known TPM's metabolites were within the range of 3.20-4.90 ng/g.Relative standard deviations(RSDs) of intra-day and inter-day precisions were less than 18.3%,which showed perfect reproducibility.The method was successfully applied to monitoring TPM's BZD metabolites in celery cabbage sprayed with TPM and the concentration versus time curves of TPM's metabolites in celery cabbage were plotted.This method is expected to be used to monitor BZD residues in various fruits and vegetables. 展开更多
关键词 Thiophonate-methyl Benzimidazole metabolites Precursor ion scan-mass spectrometry High-resolution MS/MS analysis Celery cabbage
两种异臭化合物β-环柠檬醛和β-紫罗兰酮在氯化过程中消毒副产物的生成及其影响因素 预览
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作者 郑旭辉 安娜 +2 位作者 高乃云 吴敏 徐斌 《净水技术》 CAS 2020年第1期52-57,74共7页
以两种异臭化合物β-环柠檬醛和β-紫罗兰酮作为前体物,进行氯化试验。研究两种前体物在25℃恒温黑暗条件氯化24 h后消毒副产物(DBPs)的生成及影响因素。试验结果表明,β-环柠檬醛和β-紫罗兰酮氯化后均会生成三氯甲烷(TCM)、二氯乙醛(D... 以两种异臭化合物β-环柠檬醛和β-紫罗兰酮作为前体物,进行氯化试验。研究两种前体物在25℃恒温黑暗条件氯化24 h后消毒副产物(DBPs)的生成及影响因素。试验结果表明,β-环柠檬醛和β-紫罗兰酮氯化后均会生成三氯甲烷(TCM)、二氯乙醛(DCAL)、三氯乙醛(TCAL)、二氯丙酮(DCP)和三氯丙酮(TCP),且加氯量、pH和腐植酸浓度均会影响两种前体物氯化后消毒副产物的生成量。两种前体物的试验结果有一定的相似性,随着加氯量的增加,TCM、DCP、TCP的生成量均增加;随着pH的增大,TCM的生成量增加,DCP和TCP的生成量减少,碱性条件会抑制DCAL的生成,而酸性条件会抑制TCAL的生成;随着腐植酸浓度的增加,TCM的生成量增加。 展开更多
关键词 异臭化合物 β-环柠檬醛 Β-紫罗兰酮 消毒副产物 前体物
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前驱体法制备多形貌介孔h-BN 预览
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作者 孙长红 梁宝岩 +2 位作者 王艳芝 张旺玺 李启泉 《人工晶体学报》 EI CAS 北大核心 2020年第3期494-499,共6页
以硼酸和三聚氰胺为主要原料,经微波反应,制得了不同形貌h-BN样品,分别对样品的形貌、结构、纯度和吸附性能进行了表征。研究结果显示:与烘干干燥方式相比,冷冻干燥获得的样品更为细长,冷冻处理获得样品的长径比是烘干处理的3~6倍;与未... 以硼酸和三聚氰胺为主要原料,经微波反应,制得了不同形貌h-BN样品,分别对样品的形貌、结构、纯度和吸附性能进行了表征。研究结果显示:与烘干干燥方式相比,冷冻干燥获得的样品更为细长,冷冻处理获得样品的长径比是烘干处理的3~6倍;与未添加表面活性剂的样品相比,添加表面活性剂制得的样品轮廓更为鲜明;添加盐不仅可以促进晶体生长,能使样品的形貌呈现多样性,可以产生方片状和原片状的纳米片。此外,该方法所得的h-BN具有较多的介孔,对亚甲基蓝具有较好的吸附能力,10 min吸附率高达91%以上。 展开更多
关键词 硼酸 三聚氰胺 前驱体 介孔 H-BN
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空气和氧气氧化沉淀法制备FePO4·2 H2O及LiFePO4 预览
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作者 唐涛 孙少先 应皆荣 《电源技术》 CAS 北大核心 2020年第1期17-20,共4页
以FeSO4·7 H2O和H3PO4为原料,用价格低廉的空气或氧气作为氧化剂,通过氧化沉淀法一步制得结晶态的FePO4·2 H2O。以此为前驱体制得的LiFePO4正极材料具有较好的性能。采用空气氧化时,0.2 C首次充放电比容量分别为153.5和140.8 ... 以FeSO4·7 H2O和H3PO4为原料,用价格低廉的空气或氧气作为氧化剂,通过氧化沉淀法一步制得结晶态的FePO4·2 H2O。以此为前驱体制得的LiFePO4正极材料具有较好的性能。采用空气氧化时,0.2 C首次充放电比容量分别为153.5和140.8 mAh/g,首次库仑效率为91.7%;采用氧气氧化时,0.2 C首次充放电比容量分别为168.7和153.7 mAh/g,首次库仑效率为91.1%;循环性能和倍率性能还有待改善。用X射线衍射仪和扫描电镜等对两种方法制备的FePO4·2 H2O和LiFePO4的结构和形貌进行表征。用空气或氧气代替双氧水作为氧化剂显著降低了FePO4·2 H2O前驱体的制备成本,具有应用前景,值得深入研究。 展开更多
关键词 正极材料 前驱体 空气氧化沉淀 氧气氧化沉淀 磷酸铁 磷酸铁锂
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Advances in green colloidal synthesis of metal selenide and telluride quantum dots
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作者 Dong Yao Yi Liu +1 位作者 Jing Li Hao Zhang 《中国化学快报:英文版》 SCIE CAS CSCD 2019年第2期277-284,共8页
During the past three decades, metal selenide and telluride quantum dots (QDs) have been deemed one of the most vital nanomaterials in virtue of their extensive applications, including lighting, solar harvesting,photo... During the past three decades, metal selenide and telluride quantum dots (QDs) have been deemed one of the most vital nanomaterials in virtue of their extensive applications, including lighting, solar harvesting,photocatalysis, biolabelling, quantum computing and so forth. With the growing demands for the QDrelated products, environmental friendly, energy-efficient and timesaving approaches to synthesize functional metal selenide and telluride QDs are greatly welcome. On the basis of the development in synthesis of chalcogen precursors, this mini review summarizes the recent progress in the green methods for synthesizing metal selenide and telluride QDs. At first, the panorama of basic synthetic methodology of metal chalcogenide QDs is briefly introduced. Then, numerous evolving colloidal synthetic methods are discussed, highlighting the phosphine-free precursors and the aqueous ionic precursors. Finally, this review ends with remaining challenges and future prospects in synthetic schemes. We hope this review will provide some stimulating information to promote further advancement in this area. 展开更多
关键词 Green synthesis METAL selenide/telluride Quantum dots PHOSPHINE-FREE PRECURSOR Aqueous ionic PRECURSOR
Large Earthquake Prediction Methods 预览
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作者 Manana Kachakhidze Nino Kachakhidze-Murphy +1 位作者 Badri Khvitia Giorgi Ramishvili 《地震研究(英文)》 2019年第4期239-254,共16页
At the present time rather diverse and interesting papers are published on the basis of ground-based and satellite data of earth VLF/LF and ULF electromagnetic (EM) emissions observed during earthquake preparation per... At the present time rather diverse and interesting papers are published on the basis of ground-based and satellite data of earth VLF/LF and ULF electromagnetic (EM) emissions observed during earthquake preparation period. These phenomena are detectable both at laboratory and geological scale. Today in some seismic active countries of the world the network for collecting VLF/LF electromagnetic emissions generated during the process of the earthquake preparation has been organized. Permanent monitoring of frequency spectrum of earth VLF/LF electromagnetic emissions might turn out very useful with the view of prediction of large M ≥ 5 inland earthquakes. To prove the prediction capabilities of earth electromagnetic emissions authors have used avalanche-like unstable model of fault formation and an analogous model of electromagnetic contour, synthesis of which, is rather harmonious. According to the opinion of the authors EM emissions observed during earthquake preparation period are more universal and reliable than other earthquake indicators. In the presented paper, the possible methods of the large earthquake prediction are offered on the base of the European Network of Electromagnetic Radiation (INFREP) data existent before Crete earthquake with M = 5.6 (25/05/2016, 08:36:13 UTC) earthquake. Offered methods are capable of simultaneous determination of all three parameters necessary for incoming M ≥ 5 inland large earthquake prediction (magnitude, epicenter and time of occurring) with certain accuracy. 展开更多
关键词 EARTHQUAKE PRECURSOR VLF/LF RADIO-WAVES
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An extreme-condition model for quantifying growth kinetics of colloidal metal nanoparticles
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作者 Siyu Wu Yugang Sun 《纳米研究:英文版》 SCIE EI CAS CSCD 2019年第6期1339-1345,共7页
A strategy has been developed for analyzing growth kinetics of colloidal metal nanoparticle quantitatively by focusing both the very early and the very late growth stages,at which the size of growing nanoparticles and... A strategy has been developed for analyzing growth kinetics of colloidal metal nanoparticle quantitatively by focusing both the very early and the very late growth stages,at which the size of growing nanoparticles and the reaction time follow linear functions.Applying this extremecondition model to a microwave-assistant synthesis of colloidal silver nanoparticles,for the first time,results in the determination of intrinsic kinetics parameters involving in the growth of the silver nanoparticles.The diffusion coefficient (D) of the precursor species containing Ag+ is 4.9 × 10^-14 m^2/s and the surface reaction rate constant (k) of the precursor species on the surface of the growing silver nanoparticles is 8.7 × 10^-8 m/s in an ethylene glycol solution containing 0.15 M polwinylpyrrolidone at 140 ℃.The extreme-condition model is ready to deconvolute the intrinsic kinetics parameters of growing colloidal nanoparticles once the enlargement rate of the nanoparticles can be experimentally measured in real time and with high temporal resolution.Availability of the high-fidelity values of k and D will provide the crucial information to guide the design and synthesis of colloidal metal nanoparticles with the desirable properties. 展开更多
关键词 growth kinetics of COLLOIDAL nanoparticles quantitative MODEL extreme-condition FITTING PRECURSOR DIFFUSION surface reaction of PRECURSOR
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