目的:通过体外实验评价植酸(IP6)作为根管螯合剂去除次氯酸钠溶液处理的牙本质表面玷污层的效力,探究其对次氯酸钠溶液处理的牙本质化学组成的影响。方法:24个完整无龋正畸牙取得牙本质样本随机分成4组。A组:2mL去离子水(pH7.4)处理5mi...目的:通过体外实验评价植酸(IP6)作为根管螯合剂去除次氯酸钠溶液处理的牙本质表面玷污层的效力,探究其对次氯酸钠溶液处理的牙本质化学组成的影响。方法:24个完整无龋正畸牙取得牙本质样本随机分成4组。A组:2mL去离子水(pH7.4)处理5min;B组:2 mL 5%NaClO溶液(pH12)处理5 min;C组:2 mL 5%NaClO溶液处理5min后,2mL 17%EDTA溶液(pH7.5)处理1 min;D组:2 mL 5%NaClO溶液处理5 min后,2mL 1%IP6溶液(pH1.3)处理1min。SEM观察样本表面玷污层去除情况,衰减全反射红外光谱仪(ATR-IR)测量样本红外光谱,得到处理前后的M:M(matrix:mineral)和C:M(carbonate:mineral)。以双因素重复测量方差分析比较差异。结果:SEM显示处理后A组仍有大量玷污层剩余,B组玷污层去除效果不明显,C组玷污层基本完全去除,D组玷污去除效果更加明显。ATR-IR结果经统计分析后发现,A组M:M处理前后无显著差异(P=0.744),B、C、D组均显著下降(P<0.01);处理后B、C、D组明显低于A组(P<0.01),而该3组间无显著差异(P>0.05);四组C:M处理后均略低于处理前(P<0.01)。结论:植酸能够有效地去除经次氯酸钠溶液处理后的牙本质表面的玷污层,并且其与EDTA对牙本质本身化学组成的影响无显著差别。展开更多
Electrochemical cycling of hydrogen,carbon,and nitrogen-containing molecules is of great importance to tackling energy and environmental crises and composes a central piece of the net-zero emissions scenario.Obtaining...Electrochemical cycling of hydrogen,carbon,and nitrogen-containing molecules is of great importance to tackling energy and environmental crises and composes a central piece of the net-zero emissions scenario.Obtaining an in-depth understanding of interfacial processes with molecular-level information is a cornerstone to developing more advanced electrocatalysts and electrochemical interfaces and further improving reaction efficiencies to meet industrial requirements.Among various in situ characterization techniques that can probe the interfacial processes,attenuated total reflection infrared spectroscopy(ATR-IR)has gained considerable attention most recently.A systematic review of its applications is expected to stimulate further efforts in studying the above-mentioned electrochemical reactions.Herein,we summarize the basic principles of in situ ATR-IR and its applications in understanding mechanisms of electrochemical hydrogen,carbon,and nitrogen cycling reactions,including identification of key reaction intermediates and pathways,deciphering the impacts of interfacial environments,and revealing the structure-to-performance relationship on electrocatalysts.Outlooks on challenges and opportunities faced by ATR-IR in further studying these reactions are also provided.展开更多
红外ATR光谱法(ATR-IR)用于山茶油中棕榈酸和十四烷酸含量的快速分析。配制了72个山茶油样本用于ATR光谱的采集,不同的光谱预处理方法用于光谱有效信息的提取,小波压缩(wavelet compression,WC)方法用于建模变量的优化,偏最小二乘回归(p...红外ATR光谱法(ATR-IR)用于山茶油中棕榈酸和十四烷酸含量的快速分析。配制了72个山茶油样本用于ATR光谱的采集,不同的光谱预处理方法用于光谱有效信息的提取,小波压缩(wavelet compression,WC)方法用于建模变量的优化,偏最小二乘回归(partial least square,PLS)用于脂肪酸含量的定量分析模型的构建。结果表明,ATR光谱经小波导数(wavelet derivative,WD)―标准正态变量变换(standard normal variate,SNV)预处理后,棕榈酸模型的预测相关系数(correlation coefficient of prediction,Rp)和预测均方根误差(root mean square error of prediction,RMSEP)分别为由原始光谱的0.789和3.332改善为0.908和2.653;十四烷酸模型的Rp和RMSEP分别由0.870和0.087改善为0.948和0.058;建模变量经WC预处理后由原始光谱的2 500个分别减小为190和180个,为山茶油中脂肪酸含量的测定提供了一种简便快速的分析方法。展开更多
The influence of the drop-casted nickel boride catalyst loading on glassy carbon electrodes was investigated in a spectroelectrochemical ATR-FTIR thin-film flow cell applied in alkaline glycerol electrooxidation.The c...The influence of the drop-casted nickel boride catalyst loading on glassy carbon electrodes was investigated in a spectroelectrochemical ATR-FTIR thin-film flow cell applied in alkaline glycerol electrooxidation.The continuously operated radial flow cell consisted of a borehole electrode positioned 50μm above an internal reflection element enabling operando FTIR spectroscopy.It is identified as a suitable tool for facile and reproducible screening of electrocatalysts under well-defined conditions,additionally providing access to the selectivities in complex reaction networks such as glycerol oxidation.The fast product identification by ATR-IR spectroscopy was validated by the more time-consuming quantitative HPLC analysis of the pumped electrolyte.High degrees of glycerol conversion were achieved under the applied laminar flow conditions using 0.1 M glycerol and 1 M KOH in water and a flow rate of 5μL min^(–1).Conversion and selectivity were found to depend on the catalyst loading,which determined the catalyst layer thickness and roughness.The highest loading of 210μg cm^(–2)resulted in 73%conversion and a higher formate selectivity of almost 80%,which is ascribed to longer residence times in rougher films favoring readsorption and C–C bond scission.The lowest loading of 13μg cm^(–2)was sufficient to reach 63%conversion,a lower formate selectivity of 60%,and,correspondingly,higher selectivities of C_(2)species such as glycolate amounting to 8%.Thus,only low catalyst loadings resulting in very thin films in the fewμm thickness range are suitable for reliable catalyst screening.展开更多
文摘目的:通过体外实验评价植酸(IP6)作为根管螯合剂去除次氯酸钠溶液处理的牙本质表面玷污层的效力,探究其对次氯酸钠溶液处理的牙本质化学组成的影响。方法:24个完整无龋正畸牙取得牙本质样本随机分成4组。A组:2mL去离子水(pH7.4)处理5min;B组:2 mL 5%NaClO溶液(pH12)处理5 min;C组:2 mL 5%NaClO溶液处理5min后,2mL 17%EDTA溶液(pH7.5)处理1 min;D组:2 mL 5%NaClO溶液处理5 min后,2mL 1%IP6溶液(pH1.3)处理1min。SEM观察样本表面玷污层去除情况,衰减全反射红外光谱仪(ATR-IR)测量样本红外光谱,得到处理前后的M:M(matrix:mineral)和C:M(carbonate:mineral)。以双因素重复测量方差分析比较差异。结果:SEM显示处理后A组仍有大量玷污层剩余,B组玷污层去除效果不明显,C组玷污层基本完全去除,D组玷污去除效果更加明显。ATR-IR结果经统计分析后发现,A组M:M处理前后无显著差异(P=0.744),B、C、D组均显著下降(P<0.01);处理后B、C、D组明显低于A组(P<0.01),而该3组间无显著差异(P>0.05);四组C:M处理后均略低于处理前(P<0.01)。结论:植酸能够有效地去除经次氯酸钠溶液处理后的牙本质表面的玷污层,并且其与EDTA对牙本质本身化学组成的影响无显著差别。
基金supported by the Start-up Research Fund of Southeast University(RF1028623256)。
文摘Electrochemical cycling of hydrogen,carbon,and nitrogen-containing molecules is of great importance to tackling energy and environmental crises and composes a central piece of the net-zero emissions scenario.Obtaining an in-depth understanding of interfacial processes with molecular-level information is a cornerstone to developing more advanced electrocatalysts and electrochemical interfaces and further improving reaction efficiencies to meet industrial requirements.Among various in situ characterization techniques that can probe the interfacial processes,attenuated total reflection infrared spectroscopy(ATR-IR)has gained considerable attention most recently.A systematic review of its applications is expected to stimulate further efforts in studying the above-mentioned electrochemical reactions.Herein,we summarize the basic principles of in situ ATR-IR and its applications in understanding mechanisms of electrochemical hydrogen,carbon,and nitrogen cycling reactions,including identification of key reaction intermediates and pathways,deciphering the impacts of interfacial environments,and revealing the structure-to-performance relationship on electrocatalysts.Outlooks on challenges and opportunities faced by ATR-IR in further studying these reactions are also provided.
文摘红外ATR光谱法(ATR-IR)用于山茶油中棕榈酸和十四烷酸含量的快速分析。配制了72个山茶油样本用于ATR光谱的采集,不同的光谱预处理方法用于光谱有效信息的提取,小波压缩(wavelet compression,WC)方法用于建模变量的优化,偏最小二乘回归(partial least square,PLS)用于脂肪酸含量的定量分析模型的构建。结果表明,ATR光谱经小波导数(wavelet derivative,WD)―标准正态变量变换(standard normal variate,SNV)预处理后,棕榈酸模型的预测相关系数(correlation coefficient of prediction,Rp)和预测均方根误差(root mean square error of prediction,RMSEP)分别为由原始光谱的0.789和3.332改善为0.908和2.653;十四烷酸模型的Rp和RMSEP分别由0.870和0.087改善为0.948和0.058;建模变量经WC预处理后由原始光谱的2 500个分别减小为190和180个,为山茶油中脂肪酸含量的测定提供了一种简便快速的分析方法。
文摘The influence of the drop-casted nickel boride catalyst loading on glassy carbon electrodes was investigated in a spectroelectrochemical ATR-FTIR thin-film flow cell applied in alkaline glycerol electrooxidation.The continuously operated radial flow cell consisted of a borehole electrode positioned 50μm above an internal reflection element enabling operando FTIR spectroscopy.It is identified as a suitable tool for facile and reproducible screening of electrocatalysts under well-defined conditions,additionally providing access to the selectivities in complex reaction networks such as glycerol oxidation.The fast product identification by ATR-IR spectroscopy was validated by the more time-consuming quantitative HPLC analysis of the pumped electrolyte.High degrees of glycerol conversion were achieved under the applied laminar flow conditions using 0.1 M glycerol and 1 M KOH in water and a flow rate of 5μL min^(–1).Conversion and selectivity were found to depend on the catalyst loading,which determined the catalyst layer thickness and roughness.The highest loading of 210μg cm^(–2)resulted in 73%conversion and a higher formate selectivity of almost 80%,which is ascribed to longer residence times in rougher films favoring readsorption and C–C bond scission.The lowest loading of 13μg cm^(–2)was sufficient to reach 63%conversion,a lower formate selectivity of 60%,and,correspondingly,higher selectivities of C_(2)species such as glycolate amounting to 8%.Thus,only low catalyst loadings resulting in very thin films in the fewμm thickness range are suitable for reliable catalyst screening.
