The development of innovative and sustainable catalytic strategies for organic synthesis is a pivotal aspect of advancing material science and chemical engineering.This research presents a new catalytic method for the...The development of innovative and sustainable catalytic strategies for organic synthesis is a pivotal aspect of advancing material science and chemical engineering.This research presents a new catalytic method for the aminoacylation of N-sulfonyl ketimines by utilizing a potassium-doped graphite-like carbon nitride(g-C_(3)N_(4))framework.This method not only enhances the catalytic efficiency and broadens the light absorption spectrum of g-C_(3)N_(4)but also significantly reduces the recombination rate of electronhole pairs,thereby increasing the reaction yield and selectivity.Importantly,our approach facilitates the synthesis of aminoacylated N-heterocycles,expanding the applicability of potassium-modified g-C_(3)N_(4)in photocatalytic organic synthesis.A notable accomplishment of this study is the unprecedented generation of carbamoyl radicals via heterogeneous photocatalysis,which can be easily recycled after reaction.This advancement highlights the capability of potassium-doped g-C_(3)N_(4)(namely K-CN)as an advanced heterogeneous photocatalyst for the formation of complex organic compounds.展开更多
The present study aimed to investigate the targeting effect of H7K（R2）2-modified pH -sensitive liposomes on U87-MG cells. Using coumarin-6 as a fluorescence probe, we prepared H7K（R2）2-modified p H-sensitive lipos...The present study aimed to investigate the targeting effect of H7K（R2）2-modified pH -sensitive liposomes on U87-MG cells. Using coumarin-6 as a fluorescence probe, we prepared H7K（R2）2-modified p H-sensitive liposomes（designated as coumarin-6-PSL-H7K（R2）2）. The flow cytometry assay was used to evaluate the effect of H7K（R2）2 proportions on the cellular uptake and endocytosis pathways of coumarin--6--PSL--H7K（R2）2 on U87-MG cells. The circular dichroism（CD） spectroscopy assay was used to investigate the secondary structures of H7K（R2）2 peptide at pH 7.4 and H 6.8, respectively. Our results indicated that the 2.5% proportion of H7K（R2）2 in the coumarin-6--PSL-H7K（R2）2 was superior to those of 1% and 3.5% of H7K（R2）2. The uptake of coumarin--6-PSL--H7K（R2）2 on U87--MG cells was not inhibited by filipin, M-β--CD or chlorpromazine. The secondary structure of H7K（R2）2 at pH 6.8 was mostly presented as β--turn. In conclusion, we suggested that the appropriate proportion of H7K（R2）2 in the H7K（R2）2--modified pH--sensitive liposomes could be set at 2.5%. The cellular uptake pathway for H7K（R2）2-modified pH--sensitive liposomes was via the cell penetrating capacity of H7K（R2）2 which responded to acidic condition. The secondary structure of H7K（R2）2 at pH 6.8, which was presented as the shape of hairpin, might be mainly responsible for its targeting and cell penetrating effect.展开更多
To understand the mechanism of fluoride removal from the simulated zinc sulfate solution by the La(III)-modified zeolite,the adsorbent was characterized by XRD,SEM and EDS.The effects of absorbent dose and contact tim...To understand the mechanism of fluoride removal from the simulated zinc sulfate solution by the La(III)-modified zeolite,the adsorbent was characterized by XRD,SEM and EDS.The effects of absorbent dose and contact time,the adsorption isotherms and the sorption kinetics were investigated.The experimental results were compatible with the Langmuir isotherm model.The theoretical maximum adsorption capacities are 20.83 and 23.04 mg/g at 303 and 313 K,respectively.And the physisorption is revealed using the Temkin isotherm model and the D-R isotherm model.The sorption process is more suitable by the pseudo-second-order kinetic models.Thermodynamic parameters such as standard free energy change(ΔGΘ<0 kJ/mol),standard enthalpy change(ΔHΘ=8.28 kJ/mol)and standard entropy change(ΔSΘ=0.030 kJ/(mol?K))indicate the spontaneity of adsorption and endothermic physical sorption.Furthermore,the fluoride concentration in the industrial zinc sulfate solution decreases from 98.05 to 44.09 mg/L with the adsorbent dosage of 15 g/L.展开更多
采用激光粉末床熔融(laser powder bed fusion,LPBF)技术制备K418B高温合金,利用光学显微镜、扫描电镜和硬度仪分析工艺参数激光功率(140~220 W)和扫描速度(600~1400 mm/s)对显微缺陷、致密度、微观组织及硬度的影响。结果表明,激光功...采用激光粉末床熔融(laser powder bed fusion,LPBF)技术制备K418B高温合金,利用光学显微镜、扫描电镜和硬度仪分析工艺参数激光功率(140~220 W)和扫描速度(600~1400 mm/s)对显微缺陷、致密度、微观组织及硬度的影响。结果表明,激光功率和扫描速度均显著影响样品的相对密度与缺陷分布。低能量密度易产生不规则孔洞,高能量密度则易形成球形气孔与凝固裂纹;体积能量密度(volume energy density,VED)过低或过高都会降低致密度和性能。最佳工艺参数为激光功率180 W、扫描速度1400 mm/s,在该条件下样品致密度可达99.95%以上,表面缺陷少,仅有少量凝固裂纹,显微组织呈明显熔池边界和胞状结构,维氏硬度达366.8HV_(0.2)。微观组织观察显示,熔池边界处晶粒较粗大,内部可见细胞状柱状晶,局部连续跨越多个熔池,表现出快速凝固特征。硬度随VED先升后降,与孔隙含量及致密度变化一致。研究揭示热应力是裂纹产生的主要原因,为K418B合金LPBF成形的参数优化提供依据,对提升航空发动机关键部件制造质量具有工程应用价值。展开更多
基金financial support from the National Natural Science Foundation of China(No.22171249)the Science&Technology Innovation Talents in Universities of Henan Province(No.23HASTIT003)。
文摘The development of innovative and sustainable catalytic strategies for organic synthesis is a pivotal aspect of advancing material science and chemical engineering.This research presents a new catalytic method for the aminoacylation of N-sulfonyl ketimines by utilizing a potassium-doped graphite-like carbon nitride(g-C_(3)N_(4))framework.This method not only enhances the catalytic efficiency and broadens the light absorption spectrum of g-C_(3)N_(4)but also significantly reduces the recombination rate of electronhole pairs,thereby increasing the reaction yield and selectivity.Importantly,our approach facilitates the synthesis of aminoacylated N-heterocycles,expanding the applicability of potassium-modified g-C_(3)N_(4)in photocatalytic organic synthesis.A notable accomplishment of this study is the unprecedented generation of carbamoyl radicals via heterogeneous photocatalysis,which can be easily recycled after reaction.This advancement highlights the capability of potassium-doped g-C_(3)N_(4)(namely K-CN)as an advanced heterogeneous photocatalyst for the formation of complex organic compounds.
基金Specialized Research Fund for the Doctoral Program of Higher Education(Grant No.20120001110012)the National Basic Research Program of China(973 Program,Grant No.2013CB932501)National Natural Science Foundation of China(Grant No.81172992)
文摘The present study aimed to investigate the targeting effect of H7K（R2）2-modified pH -sensitive liposomes on U87-MG cells. Using coumarin-6 as a fluorescence probe, we prepared H7K（R2）2-modified p H-sensitive liposomes（designated as coumarin-6-PSL-H7K（R2）2）. The flow cytometry assay was used to evaluate the effect of H7K（R2）2 proportions on the cellular uptake and endocytosis pathways of coumarin--6--PSL--H7K（R2）2 on U87-MG cells. The circular dichroism（CD） spectroscopy assay was used to investigate the secondary structures of H7K（R2）2 peptide at pH 7.4 and H 6.8, respectively. Our results indicated that the 2.5% proportion of H7K（R2）2 in the coumarin-6--PSL-H7K（R2）2 was superior to those of 1% and 3.5% of H7K（R2）2. The uptake of coumarin--6-PSL--H7K（R2）2 on U87--MG cells was not inhibited by filipin, M-β--CD or chlorpromazine. The secondary structure of H7K（R2）2 at pH 6.8 was mostly presented as β--turn. In conclusion, we suggested that the appropriate proportion of H7K（R2）2 in the H7K（R2）2--modified pH--sensitive liposomes could be set at 2.5%. The cellular uptake pathway for H7K（R2）2-modified pH--sensitive liposomes was via the cell penetrating capacity of H7K（R2）2 which responded to acidic condition. The secondary structure of H7K（R2）2 at pH 6.8, which was presented as the shape of hairpin, might be mainly responsible for its targeting and cell penetrating effect.
基金Projects(51474238,51674301)supported by the National Natural Science Foundation of China
文摘To understand the mechanism of fluoride removal from the simulated zinc sulfate solution by the La(III)-modified zeolite,the adsorbent was characterized by XRD,SEM and EDS.The effects of absorbent dose and contact time,the adsorption isotherms and the sorption kinetics were investigated.The experimental results were compatible with the Langmuir isotherm model.The theoretical maximum adsorption capacities are 20.83 and 23.04 mg/g at 303 and 313 K,respectively.And the physisorption is revealed using the Temkin isotherm model and the D-R isotherm model.The sorption process is more suitable by the pseudo-second-order kinetic models.Thermodynamic parameters such as standard free energy change(ΔGΘ<0 kJ/mol),standard enthalpy change(ΔHΘ=8.28 kJ/mol)and standard entropy change(ΔSΘ=0.030 kJ/(mol?K))indicate the spontaneity of adsorption and endothermic physical sorption.Furthermore,the fluoride concentration in the industrial zinc sulfate solution decreases from 98.05 to 44.09 mg/L with the adsorbent dosage of 15 g/L.
文摘采用激光粉末床熔融(laser powder bed fusion,LPBF)技术制备K418B高温合金,利用光学显微镜、扫描电镜和硬度仪分析工艺参数激光功率(140~220 W)和扫描速度(600~1400 mm/s)对显微缺陷、致密度、微观组织及硬度的影响。结果表明,激光功率和扫描速度均显著影响样品的相对密度与缺陷分布。低能量密度易产生不规则孔洞,高能量密度则易形成球形气孔与凝固裂纹;体积能量密度(volume energy density,VED)过低或过高都会降低致密度和性能。最佳工艺参数为激光功率180 W、扫描速度1400 mm/s,在该条件下样品致密度可达99.95%以上,表面缺陷少,仅有少量凝固裂纹,显微组织呈明显熔池边界和胞状结构,维氏硬度达366.8HV_(0.2)。微观组织观察显示,熔池边界处晶粒较粗大,内部可见细胞状柱状晶,局部连续跨越多个熔池,表现出快速凝固特征。硬度随VED先升后降,与孔隙含量及致密度变化一致。研究揭示热应力是裂纹产生的主要原因,为K418B合金LPBF成形的参数优化提供依据,对提升航空发动机关键部件制造质量具有工程应用价值。
