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921.
Anneli Kruve Riin Rebane Karin Kipper Maarja-Liisa Oldekop Hanno Evard Koit Herodes Pekka Ravio Ivo Leito 《Analytica chimica acta》2015
This is the part II of a tutorial review intending to give an overview of the state of the art of method validation in liquid chromatography mass spectrometry (LC–MS) and discuss specific issues that arise with MS (and MS–MS) detection in LC (as opposed to the “conventional” detectors). The Part II starts with briefly introducing the main quantitation methods and then addresses the performance related to quantification: linearity of signal, sensitivity, precision, trueness, accuracy, stability and measurement uncertainty. The last section is devoted to practical considerations in validation. With every performance characteristic its essence and terminology are addressed, the current status of treating it is reviewed and recommendations are given, how to handle it, specifically in the case of LC–MS methods. 相似文献
922.
923.
S. Sh. Mousavi 《代数通讯》2020,48(8):3184-3203
AbstractIn category theory, the existence of free objects is very important, especially free modules that play an important role in homological algebra. Although algebraic hyperstructures are a natural extension of algebraic structures, due to the major difference between them, study-free objects in algebraic hyperstructures become very difficult. In this article, we provide a categorical approach for the construction of free hypermodules. In fact, by considering appropriate morphisms between hypermodules, we characterize free hypermodules from three different perspectives. 相似文献
924.
Tengzhou Ma Ban Xuan Dong Jonathan W. Onorato Jens Niklas Oleg Poluektov Christine K. Luscombe Shrayesh N. Patel 《Journal of polymer science. Part A, Polymer chemistry》2021,59(22):2797-2808
Molecular doping of conjugated polymers (CPs) plays a vital role in optimizing organic electronic and energy applications. For the case of organic thermoelectrics, it is commonly believed that doping CPs with a strong dopant could result in higher conductivity (σ) and thus better power factor (PF). Herein, by investigating thermoelectric performance of a polar side-chain bearing CP, poly(3-(methoxyethoxyethoxy)thiophene) (P3MEET), vapor doped with fluorinated-derivative of tetracyanoquinodimethane FnTCNQ (n = 1, 2, 4), we show that using strong dopants can in fact have detrimental effects on the thermoelectric performance of CPs. Despite possessing higher electron affinity, doping P3MEET with F4TCNQ only results in a σ (27.0 S/cm) comparable to samples doped with other two weaker dopants F2TCNQ and F1TCNQ (26.4 and 20.1 S/cm). Interestingly, F4TCNQ-doped samples display a marked reduction in the Seebeck coefficient (α) compared to F1TCNQ- and F2TCNQ-doped samples from 42 to 13 μV/K, leading to an undesirable suppression of the PF. Structural characterizations coupled with Kang-Snyder modeling of the α–σ relation show that the reduction of α in F4TCNQ-doped P3MEET samples originates from the generation of low mobility carrier within P3MEET's amorphous domain. Our results demonstrate that factors such as dopant distribution and doping efficiency within the crystalline and amorphous domains of CPs should play a crucial role in advancing rational design for organic thermoelectrics. 相似文献
925.
926.
927.
928.
Assume that we have iid observations on the random vector X = (X
,...,X
) following a multivariate normal distribution N
(,) where both R
and (p.d.) are unknown. Let
denote the multiple correlation coefficient between X
and (X
,...,X
). The parameter =
, called the multiple coefficient of determination, indicates the proportion of variability in X
explained by its best linear fit based on (X
,..., X
). In this paper we consider the point estimation of under the ordinary squared error loss function. The usual estimators (MLE, UMVUE) have complicated risk expressions and hence it is quite difficult to get exact decision-theoretic results. We therefore follow the asymptotic decision theoretic approach (as done by Ghosh and Sinha (1981, Ann. Statist., 9, 1334-1338)) and study Second Order Admissibility of various estimators including the usual ones. 相似文献
929.
Chen Jixiang 《数学学报(英文版)》1998,14(3):321-326
K. A. Hardie and K. H. Kamps investigated the track homotopy categoryH
B
over a fixed spaceB ([1]). They have introduced two pairs of adjoint functors:P
B
N
B
andm
*
m
*, whereP
B
:H
B
→H
B
, andm
*:H
A
→H
B
for a fixed mapm:A→B. We have introduced a split fibration of categoriesL:H
b
→H
B
and provedL
J, J
L in [2]. This paper first extendsP
B
N
B
to
for any fixed mapb:
. Moreover we also extend these results to obtain two pairs of adjoint functors involving track homotopy categoriesH
b
andH
b
whereH
b
is the dual ofH
b
. One of our results isN
b
P
b
. This differs fromP
B
N
B
.
Supported by National Natural Science Foundation of China 相似文献
930.