Results 11 to 20 of about 93,957 (171)

时域谱元法的质量特性模型及其构建方法

open access: yesDizhen xuebao, 2022
研究了构建时域谱单元质量特性模型的数学机制,针对时域切比雪夫谱单元和勒让德谱单元建立了一种直接导出谱单元一致质量矩阵和集中质量矩阵的统一数学方法,对比分析两种谱单元质量特性模型的特征,并从物理角度探讨了谱单元质量特性模型的合理性。研究表明,数值积分点与谱单元节点选取是否一致是决定时域谱单元形成一致质量模型或集中质量模型的根本原因,当采用高斯-勒让德积分计算谱单元质量模型时将导出一致质量矩阵,而采用高斯-洛巴托积分则导出集中质量矩阵。而集中质量模型更具有物理合理性,两种谱单元质量特性模型优劣相当 ...
Hongjing Li, Jingxiong Wang
doaj   +1 more source

空间风化对C型小行星的光谱影响研究概述

open access: yesKongjian kexue xuebao, 2023
C型小行星主要由硅酸盐矿物和含碳有机质组成,保存了太阳系形成初期的原始物质,是认识太阳系形成初期的重要物质,对研究水和生命起源与演化具有重要科学意义。目前对小行星物质组成的认识主要基于光谱特征分析,但长期的空间风化作用会改变小行星表面物质的光谱特征,所以认识小行星的物质组成需要准确厘清空间风化对光谱的影响。随着中国小行星探测工程的推进,迫切需要深入认识C型小行星的光谱特征及对空间风化的响应规律。为此,分析了C型小行星的反射率、水和有机质吸收等光谱特征以及空间风化的影响,提出研究存在的主要问题 ...
周 婷   +7 more
doaj   +1 more source

The application of electrospray ionization mass spectrometry in macrobiomolecule analysis(电喷雾离子化质谱及其在生物大分子分析中的应用)

open access: yesZhejiang Daxue xuebao. Lixue ban, 2000
本文研究了一种新的离子化质谱——电喷雾离子化质谱在生物大分子分析中的应用,并与一些传统的质谱法进行了比较。
WUYi-nan(吴忆南)   +3 more
doaj   +1 more source

Research on methods for determination of diazepam residue in animal original food(动物源性食品中地西泮残留量的检测方法研究)

open access: yesZhejiang Daxue xuebao. Lixue ban, 2019
采用高效液相色谱法(HPLC)、气相色谱质谱联用法(GC-MS/MS)以及液相色谱质谱联用法(HPLCMS/ MS)测定动物源性食品中镇静剂类药物地西泮的残留量。将样品均质粉碎后,经乙腈提取,固相萃取小柱净化后上机检测,外标法定量。实验证明,当固相萃取的洗脱液中甲醇与乙酸溶液的体积比为70:30 时,洗脱效率最高。在不同仪器条件下,地西泮在各自浓度范围内的线性关系良好,相关系数(r2) 均大于0.999,回收率在 84.6%~ 101.7%,相对标准偏差(RSD) 在0.52%~9.44% (n=3 ...
DINGYuqi(丁宇琦)   +3 more
doaj   +1 more source

Qualitative analysis of polymethylsiloxane terminated with hydrogen(氢封端聚二甲基硅氧烷的定性分析)

open access: yesZhejiang Daxue xuebao. Lixue ban, 2013
使用气相色谱质谱联用(GC-MS)和电喷雾四极杆飞行时间质谱(ESI-Q-TOF)对氢封端聚二甲基硅氧烷进行分析,通过谱图解析,确定了样品中有100个相对分子质量134~3 908的组分,分别属于4种同系物,包括2种链状聚二甲基硅氧烷和2种环状聚二甲基硅氧烷.
CUILing-zhi(崔灵芝)   +2 more
doaj   +1 more source

Determination of the chemical components in tobacco extracted with supercritical carbon dioxide fluid extraction by gas chromatography/mass spectrometry(超临界CO2萃取-气相色谱\质谱分析烟丝化学成分)

open access: yesZhejiang Daxue xuebao. Lixue ban, 2006
采用超临界CO2流体萃取(SFE)和气相色谱\质谱联用提取测定了烟丝中的挥发性成分.对超临界萃取过程中的影响因素包括萃取压力、温度、萃取夹带剂等条件结合萃取物测定得到的气相色谱-质谱图进行综合考察,确定了适宜的萃取条件.与传统的蒸馏萃取法比较,超临界CO2流体萃取提取物中含较多的松油醇、烷烃、烟碱等物质.
XUZi-gang(徐子刚), ZHENGLin(郑琳)
doaj   +1 more source

Property(R) for bounded linear operator and its functions(有界线性算子及其函数的(R)性质)

open access: yesZhejiang Daxue xuebao. Lixue ban, 2022
设H为无限维复可分的Hilbert空间,B(H)为H中有界线性算子的全体。若σa(T)\σab(T)⊆π00(T),则称T∈B(H)满足(R1)性质,其中σa(T)和σab(T)分别表示算子T的逼近点谱和Browder本质逼近点谱,π00(T)={λ∈iso σ(T):0< dimN(T-λI)< ∞};若σa(T)\σab(T)=π00(T),则称T满足(R)性质。给出了有界线性算子满足(R1)性质或(R)性质的充要条件,研究了算子函数满足(R1)性质或(R)性质的判定方法,并讨论了完全 ...
ZHAOXiaopeng(赵小鹏)   +2 more
doaj   +1 more source

Polyphenol oxidase depletion in Nicotiana benthamiana enhances recombinant protein purification and preserves native protein integrity

open access: yesNew Phytologist, EarlyView.
Polyphenol oxidases (PPOs) depletion preserves endogenous proteins at their predicted molecular weights and enhances detectable enzymatic activities. (a) Less RbcL crosslinking in ppo mutant of Nicotiana benthamiana. Leaf extracts were incubated for 1 h, separated on protein gels, stained with Coomassie or analyzed by Western blot with the anti‐RbcL ...
Kaijie Zheng   +4 more
wiley   +1 more source

La3+ Vacancy Mediated Enhancement of Near‐Infrared Emission in Cr3+‐Activated La2MgTiO6 Phosphors for Multifunctional Applications

open access: yesRare Metals, Volume 45, Issue 6, June 2026.
ABSTRACT Near‐infrared (NIR) phosphors with broadband and efficient emission are pivotal for the performance of NIR phosphor‐converted light emitting diodes (pc‐LEDs). In this study, the double perovskite phosphor La2MgTiO6:Cr3+ phosphor with broadband emission in the range of 650–950 nm was prepared.
Xu Qian   +7 more
wiley   +1 more source

Atomically Thin Sn:GaN‐GaN Homojunction for High‐Sensitivity β‐Ray Detection

open access: yesRare Metals, Volume 45, Issue 6, June 2026.
ABSTRACT Gallium nitride (GaN), a third‐generation wide‐bandgap semiconductor renowned for its superior radiation tolerance, holds promise for advanced β‐ray detection. Herein, a scalable liquid metal‐assisted in situ synthesis method is presented to fabricate Sn‐doped GaN homojunctions via gallium oxide printing followed by ammonolysis, enabling ...
Weiqing Liu   +8 more
wiley   +1 more source

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