The emission spectra of BiO(A ~2Π_(1/2)) have been first obtained by studying the reaction Bi+N_2O in the heat pipe oven. 18 new bands are obtained from the emission spectra of BiO(A ~2Π_(1/2)) which are attributed to the reaction of atomic Bi~*(~2D_(3/2)) with N_2O(~1Σ_g~+). The metastable Bi~*(~2D_(3/2)) is produced by the following processes: Bi(~4S_(3/2))+N_2O(~1Σ_g~+)→BiO(X_2~2Π_(3/2)), and then,BiO(X_2~2Π_(3/2))+Bi(~4S_(3/2))→Bi~*(~2D_(3/2))+BiO(X_1~2Π_(1/2)). 相似文献
While operational qualification (OQ) is a well-established term within equipment qualification, users of equipment often become unsure when it comes to implementation. The biggest problem is how to select procedures and acceptance criteria. Should these be the vendor's specifications or should the users define their own limits, and, if so, how? Should all instruments of the same type have the same values or should these be optimized for each individual instrument? This article will provide an overall strategy and specific examples for HPLC on how to select procedures and acceptance limits that are based on efficient use of resources, on practicality and on the intended use of the equipment. 相似文献
Epibromohydrin was found to react with 7-hydroxy-2-methylpyrrolo[1,2-c]quinazolin-5(6H)-one ( 4 ) in the presence of sodium hydroxide to form the novel oxazine 5 . The structure of compound 5 was proven by cmr and pmr analysis. 相似文献
The non-isothermal crystallization behaviors of multi-walled carbon nanotubes (MWNTs)/polyamide 6 (PA6) composites were investigated by differential scanning calorimetry (DSC). Three methods, namely, Avrami, Ozawa and Mo, were carried out to analyze the non-isothermal crystallization data. The results showed that the MWNTs in PA6 acted as effective nucleation agents. However the crystallization rate of composites obtained was lower than that of the neat PA6. It is indicated that the presence of MWNTs influenced the mechanism of nucleation and the growth of PA6 crystallites. 相似文献
A modified internal lock-mass calibration method is introduced for improving the mass measurement accuracy of the product ion spectra derived from sustained off-resonance irradiation collision-induced dissociation (SORI-CID) Fourier transform ion cyclotron resonance (FTICR) mass spectrometry. This method involves an initial external calibration of the Fourier transform mass spectrometer to obtain the initial A- and B-terms for the equation (f(i) = A/(m/z)(i) + B). The A-term is adjusted by using an empirical relationship between the up-shift of the A-term and the pulse-gas duration, whereas the B-term is adjusted by using the mass of the unfragmented precursor ion from the SORI-CID mass spectrum of the unknown sample as internal lock-mass. These adjusted A- and B-terms are then used to provide exact mass SORI-CID calibration for the unknown sample. The modified internal lock-mass method achieved average mass measurement accuracy of approximately 3 ppm which is significantly better than that of the conventional internal lock-mass calibration ( approximately 9 ppm) and is approaching that of the internal calibration ( approximately 2 ppm) and requires no addition of internal calibrant or instrumental modifications. 相似文献
Quality inspection is essential in preventing defective products from entering the market. Due to the typically low percentage of defective products, it is generally challenging to detect them using algorithms that aim for the overall classification accuracy. To help solve this problem, we propose an ensemble learning classification model, where we employ adaptive boosting (AdaBoost) to cascade multiple backpropagation (BP) neural networks. Furthermore, cost-sensitive (CS) learning is introduced to adjust the loss function of the basic classifier of the BP neural network. For clarity, this model is called a CS-AdaBoost-BP model. To empirically verify its effectiveness, we use data from home appliance production lines from Bosch. We carry out tenfold cross-validation to evaluate and compare the performance between the CS-AdaBoost-BP model and three existing models: BP neural network, BP neural network based on sampling, and AdaBoost-BP. The results show that our proposed model not only performs better than the other models but also significantly improves the ability to identify defective products. Furthermore, based on the mean value of the Youden index, our proposed model has the highest stability.
The infinitely many symmetries with arbitrary functions of timet for the potential modified Kadomtsev-Petviashvilli equation are obtained by using a simple direct method. These symmetries constitute a generalization of the well-knownW algebra. 相似文献