Some existing fault detection methods for the semiconductor process, such as principal component analysis and locality preserving projections (LPP), are linear algorithms, so they degrade the performance of fault detection in a nonlinear process. In addition, they are not effective for fault detection in a multimodal process. To solve the problems caused by nonlinear and multimodal characteristics in the semiconductor process, a new difference (DIF) pre-processing strategy is proposed to normalize the nonlinear and multimodal data. After detailed analysis of DIF, a new method called DIF-LPP is developed for fault detection in the semiconductor process. The nonlinear and multimodal data can be transformed into data sets that follow a Gaussian and single mode distribution, respectively. The proposed method contains a model without prior knowledge of the nonlinear and multimodal process. To demonstrate the proposed method's effectiveness, it is applied to 2 numerical examples and the semiconductor process. Simulation results verify that the proposed method is effective for fault detection in the nonlinear and multimodal process.

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Rabeprazole sodium (RAB) dissolved in acidic media is accompanied by its degradation in the course of dissolution testing. To develop and establish the accumulative release profiles of ACIPHEX® Sprinkle (RAB) delayed-release capsules (ACIPHEX® Sprinkle) in acidic media using USP apparatus 2 (paddle apparatus) as a dissolution tester, the issues of determination of accumulative release amount of RAB in these acidic media and interference of hydroxypropylmethyl cellulose phthalate were solved by adding appropriate hydrochloric acid (HCl) into dissolution samples coupled with centrifugation so as to remove the interference and form a solution of degradation products of RAB, which is of a considerably stable ultraviolet (UV) absorbance at the wavelength of 298 nm within 2.0 h. Therefore, the accumulative release amount of RAB in dissolution samples at each sample time points could be determined by UV-spectrophotometry, and the accumulative release profiles of ACIPHEX® Sprinkle in the media of pH 1.0, pH 6.0, and pH 6.8 could be established. The method was validated per as the ICH Q2 (R1) guidelines and demonstrated to be adequate for quality control of ACIPHEX® Sprinkle and the accumulative release profiles can be used as a tool to guide the formulation development and quality control of a generic drug for ACIPHEX® Sprinkle.

Aimed at the characteristics of complex continental shale lithology, the development of sandy striae, and the difficulty of artificial recognition. In this paper, the sandy texture of the Chang 7 shale gas reservoir in the Mesozoic of the Yanchang Oilfield is taken as the research object. First, the core fine observation description and X-ray diffraction analysis of the whole rock minerals were carried out to determine the development characteristics of sandy striae of continental shale. Then the research focuses on methods such as full-wellbore wall restoration, automatic identification of the striae boundary, and construction of the striae development index model for the electric imaging log images. Finally, comprehensive evaluation is made on the sandy stratum of the extended continental shale gas reservoir. The results show that the mineral types of Changqi shale in the study area are mainly clay minerals, quartz and feldspar, and the average thickness of sandy lamina is 1.93cm, with a layer density of 26 layers/m. After verification and analysis with core description, the method based on image recognition can accurately identify the striae layer, which lays a foundation for shale gas layer selection in the study area.