[Objectives]The paper was to establish an ultra high performance liquid chromatography-quadrupole/linear ion trap complex mass spectrometry for the determination of 10 kinds ofα2-receptor agonists in animal derived f...[Objectives]The paper was to establish an ultra high performance liquid chromatography-quadrupole/linear ion trap complex mass spectrometry for the determination of 10 kinds ofα2-receptor agonists in animal derived food.[Methods]The samples were extracted with sodium carbonate buffer solution and ethyl acetate,and analyzed by mass spectrometry after solid phase extraction and high performance liquid chromatography separation.[Results]Ten kinds ofα2-receptor agonists showed a good linear relationship in the range of 1-100μg/mL,with the average recovery of over 69%and the relative standard deviation less than 8.32%.The detection limit of 10 kinds of α_(2)-receptor agonists was up to 1μg/kg.[Conclusions]The method has good selectivity and strong anti-interference ability,and can meet the requirements of 10 kinds ofα2-receptor agonists residues in animal derived food.展开更多
The graded AlGaN:Si back barrier can form the majority of three-dimensional electron gases(3DEGs)at the GaN/graded AlGaN:Si heterostructure and create a composite two-dimensional(2D)-three-dimensional(3D)channel in Al...The graded AlGaN:Si back barrier can form the majority of three-dimensional electron gases(3DEGs)at the GaN/graded AlGaN:Si heterostructure and create a composite two-dimensional(2D)-three-dimensional(3D)channel in AlGaN/GaN/graded-AlGaN:Si/GaN:C heterostructure(DH:Si/C).Frequency-dependent capacitances and conductance are measured to investigate the characteristics of the multi-temperature trap states of in DH:Si/C and AlGaN/GaN/GaN:C heterostructure(SH:C).There are fast,medium,and slow trap states in DH:Si/C,while only medium trap states exist in SH:C.The time constant/trap density for medium trap state in SH:C heterostructure are(11μs-17.7μs)/(1.1×10^13 cm^-2·eV^-1-3.9×10^13 cm^-2·eV^-1)and(8.7μs-14.1μs)/(0.7×10^13 cm^-2·eV^-1-1.9×10^13 cm^-2·eV^-1)at 300 K and 500 K respectively.The time constant/trap density for fast,medium,and slow trap states in DH:Si/C heterostructure are(4.2μs-7.7μs)/(1.5×10^13 cm^-2·eV^-1-3.2×10^13 cm^-2·eV^-1),(6.8μs-11.8μs)/(0.8×10^13 cm^-2·eV^-1-2.8×10^13 cm^-2·eV^-1),(30.1μs-151μs)/(7.5×10^12 cm^-2·eV^-1-7.8×10^12 cm^-2·eV^-1)at 300 K and(3.5μs-6.5μs)/(0.9×10^13 cm^-2·eV^-1-1.8×10^13 cm^-2·eV^-1),(4.9μs-9.4μs)/(0.6×10^13 cm^-2·eV^-1-1.7×10^13 cm^-2·eV^-1),(20.6μs-61.9μs)/(3.2×10^12 cm^-2·eV^-1-3.5×10^12 cm^-2·eV^-1)at 500 K,respectively.The DH:Si/C structure can effectively reduce the density of medium trap states compared with SH:C structure.展开更多
A composition-modulated （HfO2）x（Al2O3）1-x charge trapping layer is proposed for charge trap flash memory by controlling the A1 atom content to form a peak and valley shaped band gap. It is found that the memory de...A composition-modulated （HfO2）x（Al2O3）1-x charge trapping layer is proposed for charge trap flash memory by controlling the A1 atom content to form a peak and valley shaped band gap. It is found that the memory device using the composition-modulated （HfO2）x（Al2O3）l-x as the charge trapping layer exhibits a larger memory window of 11.5 V, improves data retention even at high temperature, and enhances the program/erase speed. Improvements of the memory characteristics are attributed to the special band-gap structure resulting from the composition-modulated trapping layer. Therefore, the composition-modulated charge trapping layer may be useful in future nonvolatile flash memory device application.展开更多
Based mainly on the work done at the authors' laboratory in recent years,this paper examines what is currently known about the cyclic deformation and fatigue properties of metal matrix composites, with particular ...Based mainly on the work done at the authors' laboratory in recent years,this paper examines what is currently known about the cyclic deformation and fatigue properties of metal matrix composites, with particular emphasis on discontinuous fiber (whisker or particulate)-reinforced Al composites. The following items are discussed:fatigue strength and life,cyclic deformation and microstructural evolution,microcrack initiation and growth,fatigue crack propagation behaviour.展开更多
目的基于高效液相色谱-三重四极杆/复合线性离子阱质谱法(high performance liquid chromatography-triple quadrupole/composite linear ion trap mass spectrometry,HPLC-QTRAP MS)建立同时测定液态发酵食品中14中生物胺及其代谢物的...目的基于高效液相色谱-三重四极杆/复合线性离子阱质谱法(high performance liquid chromatography-triple quadrupole/composite linear ion trap mass spectrometry,HPLC-QTRAP MS)建立同时测定液态发酵食品中14中生物胺及其代谢物的分析方法。方法采用Waters Atlantis Premier BEH Z-HILIC色谱柱(100mm×2.1mm,1.7μm),以0.025%(V/V)甲酸水和0.1%(V/V)甲酸乙腈进行梯度洗脱,电喷雾离子源(electrospray ionization,ESI)正离子模式、多反应监测(multiple reaction monitoring,MRM)离子扫描模式、信息依赖性采集(information dependent acquisition,IDA)、增强子离子扫描(enhanced ion scanning,EPI)和EPI谱库搜索的复合模式进行测定。结果在0.05~200.00μg/L质量浓度范围内,14种生物胺及其代谢物的线性关系良好,相关系数均大于0.99;方法检出限(S/N=3)为0.15~6.00μg/L;在不同添加质量浓度(2.0、10.0、50.0μg/L)下,其回收率为75.2%~107.9%,相对标准偏差在1.98%~9.07%之间。结论该方法具有操作简便、快速、准确、灵敏等优点,可满足液态类发酵食品中14种生物胺的定性定量分析需要,为液态发酵类食品中生物胺的检测分析奠定基础。展开更多
基金Supported by Scientific Research Project of Dalian Customs(2022DK09).
文摘[Objectives]The paper was to establish an ultra high performance liquid chromatography-quadrupole/linear ion trap complex mass spectrometry for the determination of 10 kinds ofα2-receptor agonists in animal derived food.[Methods]The samples were extracted with sodium carbonate buffer solution and ethyl acetate,and analyzed by mass spectrometry after solid phase extraction and high performance liquid chromatography separation.[Results]Ten kinds ofα2-receptor agonists showed a good linear relationship in the range of 1-100μg/mL,with the average recovery of over 69%and the relative standard deviation less than 8.32%.The detection limit of 10 kinds of α_(2)-receptor agonists was up to 1μg/kg.[Conclusions]The method has good selectivity and strong anti-interference ability,and can meet the requirements of 10 kinds ofα2-receptor agonists residues in animal derived food.
基金the National Key Research and Development Program of China(Grant No.2018YFB1802100)the Natural Science Foundation of Shaanxi Province,China(Grant Nos.2020JM-191 and 2018HJCG-20)+2 种基金the National Natural Science Foundation of China(Grant Nos.61904135,61704124,and 61534007)the China Postdoctoral Science Foundation(Grant Nos.2018M640957 and 2019M663930XB)the Wuhu and Xidian University Special Fund for Industry-University-Research Cooperation,China(Grant No.XWYCXY-012019007).
文摘The graded AlGaN:Si back barrier can form the majority of three-dimensional electron gases(3DEGs)at the GaN/graded AlGaN:Si heterostructure and create a composite two-dimensional(2D)-three-dimensional(3D)channel in AlGaN/GaN/graded-AlGaN:Si/GaN:C heterostructure(DH:Si/C).Frequency-dependent capacitances and conductance are measured to investigate the characteristics of the multi-temperature trap states of in DH:Si/C and AlGaN/GaN/GaN:C heterostructure(SH:C).There are fast,medium,and slow trap states in DH:Si/C,while only medium trap states exist in SH:C.The time constant/trap density for medium trap state in SH:C heterostructure are(11μs-17.7μs)/(1.1×10^13 cm^-2·eV^-1-3.9×10^13 cm^-2·eV^-1)and(8.7μs-14.1μs)/(0.7×10^13 cm^-2·eV^-1-1.9×10^13 cm^-2·eV^-1)at 300 K and 500 K respectively.The time constant/trap density for fast,medium,and slow trap states in DH:Si/C heterostructure are(4.2μs-7.7μs)/(1.5×10^13 cm^-2·eV^-1-3.2×10^13 cm^-2·eV^-1),(6.8μs-11.8μs)/(0.8×10^13 cm^-2·eV^-1-2.8×10^13 cm^-2·eV^-1),(30.1μs-151μs)/(7.5×10^12 cm^-2·eV^-1-7.8×10^12 cm^-2·eV^-1)at 300 K and(3.5μs-6.5μs)/(0.9×10^13 cm^-2·eV^-1-1.8×10^13 cm^-2·eV^-1),(4.9μs-9.4μs)/(0.6×10^13 cm^-2·eV^-1-1.7×10^13 cm^-2·eV^-1),(20.6μs-61.9μs)/(3.2×10^12 cm^-2·eV^-1-3.5×10^12 cm^-2·eV^-1)at 500 K,respectively.The DH:Si/C structure can effectively reduce the density of medium trap states compared with SH:C structure.
基金supported by the Science and Technology Research Key Project of Education Department of Henan, China (Grant No. 13A140021)the National Natural Science Foundation of China (Grant Nos. 50972054 and 61176124)+1 种基金the National Basic Research Program of China (Grant No. 2010CB934201)the State Key Program for Science and Technology of China (Grant No. 2009ZX02039-004)
文摘A composition-modulated （HfO2）x（Al2O3）1-x charge trapping layer is proposed for charge trap flash memory by controlling the A1 atom content to form a peak and valley shaped band gap. It is found that the memory device using the composition-modulated （HfO2）x（Al2O3）l-x as the charge trapping layer exhibits a larger memory window of 11.5 V, improves data retention even at high temperature, and enhances the program/erase speed. Improvements of the memory characteristics are attributed to the special band-gap structure resulting from the composition-modulated trapping layer. Therefore, the composition-modulated charge trapping layer may be useful in future nonvolatile flash memory device application.
文摘Based mainly on the work done at the authors' laboratory in recent years,this paper examines what is currently known about the cyclic deformation and fatigue properties of metal matrix composites, with particular emphasis on discontinuous fiber (whisker or particulate)-reinforced Al composites. The following items are discussed:fatigue strength and life,cyclic deformation and microstructural evolution,microcrack initiation and growth,fatigue crack propagation behaviour.
文摘目的基于高效液相色谱-三重四极杆/复合线性离子阱质谱法(high performance liquid chromatography-triple quadrupole/composite linear ion trap mass spectrometry,HPLC-QTRAP MS)建立同时测定液态发酵食品中14中生物胺及其代谢物的分析方法。方法采用Waters Atlantis Premier BEH Z-HILIC色谱柱(100mm×2.1mm,1.7μm),以0.025%(V/V)甲酸水和0.1%(V/V)甲酸乙腈进行梯度洗脱,电喷雾离子源(electrospray ionization,ESI)正离子模式、多反应监测(multiple reaction monitoring,MRM)离子扫描模式、信息依赖性采集(information dependent acquisition,IDA)、增强子离子扫描(enhanced ion scanning,EPI)和EPI谱库搜索的复合模式进行测定。结果在0.05~200.00μg/L质量浓度范围内,14种生物胺及其代谢物的线性关系良好,相关系数均大于0.99;方法检出限(S/N=3)为0.15~6.00μg/L;在不同添加质量浓度(2.0、10.0、50.0μg/L)下,其回收率为75.2%~107.9%,相对标准偏差在1.98%~9.07%之间。结论该方法具有操作简便、快速、准确、灵敏等优点,可满足液态类发酵食品中14种生物胺的定性定量分析需要,为液态发酵类食品中生物胺的检测分析奠定基础。
