Positive Switching Research Articles

A target-group-change couple with mass defect filtering strategy to identify the metabolites of "Dogel ebs" in rats plasma, urine and bile.

"Dogel ebs" was known as Sophora flavescens Ait., a classical traditional Chinese Mongolian herbal medicine, which had the effects on damp-heat dysentery, scrofula, and syndrome of accumulated dampness toxicity. Although the chemical constituents have been clarified by our previous studies, the metabolic transformation of "Dogel ebs" in vivo was still unclear. To explore the mechanism of "Dogel ebs," the metabolites in plasma, bile, and urine samples were investigated. A fast positive and negative ion switching technology was used for the simultaneous determination of flavonoids and alkaloids in "Dogel ebs" in a single run. And a target-group-change coupled with mass defect filtering strategy was utilized to analyze the collected data. 89 parent compounds and 82 metabolites were characterized by high-performance liquid chromatography with quadrupole exactive Orbitrap mass spectrometry. Both phase I and phase II metabolites were observed and the metabolic pathways involved in oxidation, demethylation, acetylation, and glucuronidation. 69 metabolites of "Dogel ebs," including three hydroxyls bonding xanthohumol, formononetin-7-O-glucuronide, 2'-hydroxyl-isoxanthohumol decarboxylation metabolite, oxysophocarpine dehydrogen, 9α-hydroxysophoramine-O-glucuronide, etc. were reported for the first time.

Tolerance‐based reliability and optimization design of switched‐mode power supply

AbstractDue to its high efficiency and low power consumption, switched‐mode power supply (SMPS) represents the development trend of the stabilized voltage power supply. However, tolerance has become one of the key factors in the design of SMPS because of the process fluctuation of electronic components, unstable input parameters of the circuit system, influence of working conditions and environment, and the effect of aging. In order to improve the reliability of SMPS and reduce the manufacturing cost, this paper proposes a reliability analysis and optimization design method based on the tolerance and sensitivity analysis. Finally, this method is applied to the tolerance design for the positive switching power supply of the SMPS circuits, and the optimal tolerance design scheme is obtained. Furthermore, the reliability and probability density curves are evaluated.

Stability Analysis for State-constrained Switched Systems with All Subsystems Unstable

This paper mainly investigates the state constrained switched system with fully unstable subsystems. By limiting the state in a unit hypercube, a sufficient condition is derived to ensure the stability of such systems via a time-dependent strategy. The main idea is to use positive switching behavior to compensate state divergence caused by unstable states and setting a different ascend rate when state constraints occur or not. In order to make the conditions computable for a continuous-time switched systems with state constraints, the discretized Lyapunov Function method is applied, then a numerical example is given to show the practicability of the proposed method.

On the stem diameter under positive impulses in long air gaps

The diameter of a stem, a common origin point for streamers where the transition from the streamer to the leader takes place, has a significant effect on the simulation of streamer-to-leader transition. To measure the diameter of the stem, a schlieren system was established with the temporal and spatial resolutions of 5 μs and 70 μm, respectively. Experiments were conducted under positive lightning and switching impulses; the applied voltage, discharge current, and schlieren images were recorded synchronously. A method was proposed to measure the diameter of the stem based on the schlieren images, with which the stem diameter as a function of time was obtained. Moreover, the initial diameters of the stem under different conditions were obtained through the linear fitting. At last, a relation between the initial cross-sectional area of the stem and the discharge current was given within a certain range.

Switching Barriers in Online Travel Agencies: The Impact on Positive Word of Mouth

This research attempts to clarify the different approaches followed in the literature to describe switching barriers. It helps identify and shed light on the wide variety of barriers that firms must manage. The study evaluates the role of switching barriers in online environments, distinguishing between positive and negative barriers, and examines the factors that favor positive recommendations to other customers. To test the causal relationships between switching barriers, trust, affective commitment, and positive recommendations, a model was constructed and estimated using the SEM methodology. The findings show that positive switching barriers affect positive recommendations both directly and indirectly through their effect on trust. Negative switching barriers, in contrast, only have a direct and negative effect on positive recommendations. It is fundamental for virtual travel agencies to be trained to recognize when their customers are staying willingly and when they feel locked into their relationships.

Influence of front time on positive switching impulse discharge characteristics of UHVDC tower gaps

The front time of switching impulses has a significant influence on long air gap discharge performance, but most testing experiments have been conducted using standard impulses. Here, we carried out experiments investigating the discharge characteristics of a ±800 kV transmission line-tower gap (5–8 m) under positive switching impulses with different front times and obtained important physical parameters, such as the time and voltage of the leader inception, the leader propagation velocity, and the 50% breakdown voltage (U50). The results show that (1) the critical wave front time increases with the air gap distance; (2) for the tested gaps, the time and voltage of the leader inception show minimum dispersion when the front time is 250 μs; (3) an approximately U-shaped curve occurs between the front time and the average velocity of the continuous leader propagation, and the velocity is the slowest with a front time of 500 μs. The results illustrated that choosing standard switching impulses (250 μs/2500 μs) to conduct a discharge test in a ±800 kV transmission line-tower gap is both suitable and effective; however, when the operation voltage further increases, the front time should be increased appropriately when conducting switching impulse tests.

Fast chopper for single radio-frequency quadrupole bunch selection for neutron time-of-flight capabilities

A fast chopper system has been developed and tested for single bunch selection with the radio-frequency quadrupole (RFQ) accelerating element of the Soreq Applied Research Accelerator Facility (SARAF). The fast chopper consists of a high voltage (HV) deflector just before the RFQ, providing both positive and negative HV deflections and fast HV switching between polarities to enable momentary transmission of a single prebunch to the RFQ. Presently, the system enables single bunch selection for protons and deuterons at a repetition rate as determined by the user of up to 200 kHz, with bunch transmission of up to 50%, and with neighboring bunch contamination of less than 15%. Single bunch selection provides SARAF with fast neutron time-of-flight (TOF) capabilities. Measurements performed with liquid scintillation detectors show clear gamma and neutrons peaks, with TOF resolution of about 1 nanosecond FWHM. Beam dynamics simulations suggest possibilities for further improvements of the fast chopper and single bunch selection characteristics, with a significant lowering or elimination of the neighboring bunches, enhanced TOF resolution, and increased repetition rate to above 200 kHz. Fast neutron TOF capabilities, especially at phase II of SARAF, will provide exceptional opportunities for neutron induced reaction measurements for nuclear technology and fundamental research.

Robust finite-time stabilization for positive delayed semi-Markovian switching systems

Robust finite-time stabilization is discussed for positive semi-Markovian switching systems (S-MSSs), in which semi-Markovian process, time-varying delay, external disturbance, and transient performance in finite-time level are all considered in a unified framework. In the system under consideration, finite-time problem can describe transient performance of practical control process. Firstly, some finite-time boundedness and L1 finite-time boundedness criteria for positive delayed S-MSSs are proposed by constructing the stochastic semi-Markovian Lyapunov–Krasovskii functional with mode-dependent integral term. Then, a developed L1 finite-time feedback controller design method is presented to reduce some constraints of input matrices, which guarantees the resulting closed-loop system achieves positivity, finite-time boundedness, and has a prescribed L1 noise attenuation performance index in a novel standard linear programming. Finally, a practical example is illustrated to validate the proposed results by applying a virus mutation treatment model.

Established UPLC-MS/MS procedure for multicomponent quantitative analysis in rat plasma: A contrastive pharmacokinetics study of Qiangshen tablet in normal and kidney yang deficiency syndrome models

Qiangshen tablet, an important prescription consisting of 14 kinds of Chinese herbal medicines, has been used for decades to treat kidney yang deficiency syndrome (KYDS) in China. Qiangshen tablet has been recorded in ChP (2015 edition) and possesses the effect of strengthening yang, invigorating qi and tonifying kidneys. In this research, a simple, reliable and specific method was established for simultaneous determination of stachydrine, psoralen, isopsoralen, morroniside, paeoniflorin and loganin in normal and KYDS rat plasma after intragastric administration of a Qiangshen tablet suspension by UPLC-MS/MS. Protein precipitation (PP) by acetonitrile and liquid-liquid extraction (LLE) by ethyl acetate - n-butanol (1: 1, v/v) were used for pretreatment of plasma samples. Chromatographic separation of two IS (Internal Standard) and six analytes was achieved using an ACQUITY UPLC® BEH C18 column (2.1 × 100 mm, 1.7 μm). The mobile phase consisted of 0.1% formic acid aqueous solution (solvent A) and acetonitrile (solvent B) with a gradient scheme. Multiple reaction monitoring (MRM) mode with positive and negative ion source switching was applied to perform the mass spectrometric analyses. This method has been validated with good linearity (r ≥ 0.9942) and acceptable precision and accuracy (RSD ≤ 11%, RE from −4.8% to 7.7%). The mean recovery values of the analytes and IS were all ≥68.28%, and the matrix effects ranged from 94.4% to 101.7%. The stability of the IS and analytes was measured throughout the experiment. The results showed significant differences between the pharmacokinetic traits of the analytes in the normal and KYDS groups, suggesting that pharmacokinetic procedures involving these analytes could be modified in cases of KYDS.

A Penalty Scheme for Monotone Systems with Interconnected Obstacles: Convergence and Error Estimates

We present a novel penalty approach for a class of quasi-variational inequalities (QVIs) involving monotone systems and interconnected obstacles. We show that for any given positive switching cost, the solutions of the penalized equations converge monotonically to those of the QVIs. We estimate the penalization errors and are able to deduce that the optimal switching regions are constructed exactly. We further demonstrate that as the switching cost tends to zero, the QVI degenerates into an equation of HJB type, which is approximated by the penalized equation at the same order (up to a log factor) as that for positive switching cost. Numerical experiments on optimal switching problems are presented to illustrate the theoretical results and to demonstrate the effectiveness of the method.

Modeling of Positive Switching Impulse Discharge of UHV Transmission Line Air Gaps

Positive switching impulse discharge characteristics are an important basis for the external insulation design of transmission line towers. At present, the characteristics are obtained mainly by real tower discharge tests. Since the existing research on the discharge model is not perfect, test designs are not reasonable, which results in high costs. The influence of line height and tower width on the discharge characteristics of Ultra High Voltage (UHV) transmission lines air gaps is studied in this paper. The results show that the line height had little influence on the breakdown voltage of air gaps in UHV transmission lines. A tower-width discharge model was obtained by fitting the breakdown voltage of air gaps with different gap lengths and tower widths. By analyzing the gap characteristic factors of different transmission lines, a discharge model of different tower air gaps in UHV transmission lines was presented. The breakdown voltage calculated by the models was in good agreement with the test results, and the errors were not more than 5%.

Simultaneous quantification of fifteen compounds in rat plasma by LC-MS/MS and its application to a pharmacokinetic study of Chaihu-Guizhi decoction

A simple, sensitive and selective high-performance liquid chromatography electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS) method was developed and validated for simultaneous determination and pharmacokinetic study of 15 active compounds (Saikosaponin A, Baicalin, Wogonin, Glycyrrhizic acid, Glycyrrhetinic acid, Albiflorin, Paeoniflorin, Liquiritin, Isoliquiritin, Liquiritigenin, Isoliquiritigenin, Cinnamic acid, Gallic acid, Wogonoside and Oroxylin A) in rat plasma. After a feasible protein precipitation using methanol for sample preparation, chromatographic separation was carried out with a Halo® C18 column (2.1 × 100 mm, 2.7 μm) at 35 °C, water containing 0.1% formic acid and acetonitrile were used as the mobile phase with a flow rate of 0.3 mL/min. Multiple reaction monitoring (MRM) with positive and negative ion switching mode was performed for the quantification of the standards and internal standard in plasma. All the calibration curves showed good linear regression within the linear range (r2 > 0.9923). In particular, the results of the method validation including specificity, linearity, accuracy, precision, extraction recovery, matrix effect, and stability of compounds in bio-samples were all within the current acceptance criteria. The established method was successfully applied to the pharmacokinetic study of 15 compounds in rats after oral administration of CGD and laid the foundation for studying the active components and mechanism of CGD in vivo.

Factors Influencing Brand Switching Behavior: Role Of Variety Seeking Need As Moderator Variable

The aims of research were to analyze the effect of dissatisfaction as well as characteristic ofproduct category on brand switching, to analyze the moderating role of variety seeking needon the causal relationship between dissatisfaction as well as characteristic of productcategory and brand switching, and so to analyze the direct effect of perceived price as wellas competitors’ promotion on brand switching. Type of this research uses survey. Populationof this research was all customers of smartphone in Purbalingga who ever use the Samsungbrand and they switch to another brand of smartphone product which the number isuncertainty. Sampling technique of this study used interval estimate technique and theopinion by Hair et al., so it could be determined that sample size within study was 150respondents. Furthermore, technique data analysis of this study used Structural EquationModel (SEM) analysis. Based on the result of data analysis, it could be concluded thatdissatisfaction as well as characteristics of product category has a positive influence onbrand switching, need of variety seeking no moderates the influence of dissatisfaction aswell as characteristics of product category on brand switching, and perceived price toanother brand as well as competitors’ promotion has a positive influence on brand switching.Refers to these conclusions, it could be implied that in order to minimize its customers’brand switching behavior, marketing manager of Samsung smartphone products needs tomake priority on marketing policy to address the customer dissatisfaction, characteristic ofproduct category, need of variety seeking, perceived price and competitors’ promotionpolicies. The ways can be done by decrease the several risks are faced by Samsungsmartphone users and always to follow up the customers’ complaints related to theproblems or error of the Samsung smartphone product quickly and accurately, create thespecific products of smartphone which cannot be imitated by competitors, apply the productdiversification strategy through modifying existing products or adding the new product basedon price levels and target market segmentation, make the various technological innovationsto improve the quality and usefulness of smartphone products in accordance with thechanging needs, desires and consumers’ preferences, set price of Samsung smartphoneproducts that are cheaper than price of competitors’ smartphone products with still maintainthe quality and benefits of Samsung smartphone products, and build the brand image of“SAMSUNG”, and always maintain and strengthen the quality of long-term marketingrelationships with its customers to keep them from being influenced by the promotionalprograms of competitors’ product or brand.

Formula omitted] finite-time stabilization for positive semi-Markovian switching systems

This paper investigates robust finite-time stabilization scheme for positive semi-Markovian switching systems (S-MSSs). Semi-Markovian process (SMP), external disturbances, and transient performances at a finite-time level may appear in a controlled system. A more general system model for S-MSSs that covers Markovian switching systems (MSSs) as a special case is suitable for describing some complex systems that are subject to random abrupt changes in structure and parameter. The main motivation for this is that finite-time problems can be used to describe the transient performance of practical industrial control processes. First, under the framework of stochastic semi-Markovian Lyapunov functions theory, some sufficient conditions for finite-time boundedness (FTBs) and L1 FTBs criteria for positive S-MSSs are proposed for all admissible disturbances. Then, a novel L1 finite-time controller design method that employs the gain matrix decomposition method is presented to reduce some conservativeness, thereby guaranteeing that the resulting closed-loop system (RLCS) could achieve positivity, FTBs, and attain a prescribed L1 noise attenuation performance index in standard linear programming (LP). Finally, a practical example is introduced to show the effectiveness of the main theory

Number of stems around the H.V. electrode in a 0.74-m air gap under positive impulse

Stem is a special short bright zone for the streamer to leader transition in long air gap discharges, whose characteristics play an important role in leader initiation and development. For the purpose of observing the number of stems around the H.V. electrode at the initial corona discharge, experiments were conducted under positive switching and lightning impulses with different crest values, and the schlieren photographs of stems and the discharge current were recorded synchronously. The associated analysis of the experimental results shows that the number of stems around the electrode at the initial corona discharge is always more than one in most cases. In addition, the average number of stems increases with the radius of the electrode and the crest value of applied impulse. If we focus on the characteristic of only one stem for special study, the conditions with a lower crest value under switching impulse and the electrode with a radius as small as possible are preferable.

Influences of surface tips of a shield ball on the discharge characteristics of a long sphere‐plane air gap under positive switching impulses

The study established a test platform for a long sphere-plane air gap in the test hall of the ultra-high voltage (UHV) direct current(DC) Testing Site. Under the sphere-plane gaps with 3, 5 and 7 m distance, the study carried out the experiment on discharge characteristics under switching impulses on a shield ball on which surface tips had different lengths at different locations. By comparing with the test data obtained under conditions with a smooth surface of the shield ball and the same gap distance, the discharge laws under the influence of surface tips on the shield ball are shown as follows: the presence of the tips greatly decreased the discharge voltage of the sphere-plane gap with the maximum decrease amplitude of 39.0%. Moreover, the decrease degree was increasingly significant with the growing length of tips. The influence of the same length of tips on the discharge voltage of the gap gradually declined with the growth of the gap distance. The presence of tips significantly reduced the discharge voltage, especially in the perpendicular line of the shield ball. The results indicate that it's necessary to strictly control the machining and installation to avoid the occurrence of tips in UHV DC engineering.

Multiclass mycotoxins in lotus seeds analysed by an isotope-labelled internal standard-based UPLC-MS/MS.

This study aimed to explore the residue levels of multiclass mycotoxins in medicinal and edible lotus seeds. A rapid and reliable isotope-labelled internal standard-based UPLC-MS/MS method was developed and validated for sensitive and accurate analysis of multiclass mycotoxins including aflatoxins (AFB1 , AFB2 , AFG1 and AFG2 ), ochratoxin A (OTA), zearalenone (ZEN), deoxynivalenol (DON), fumonisins (FB1 and FB2 ), T-2 and HT-2 toxins in lotus seeds. Some critical conditions such as extract solution with the addition of isotope-labelled internal standard, type of mobile phase and the elution condition were scientifically optimized. The 11 mycotoxins obtained satisfactory resolution and sensitive detection in multiple reactions monitoring scanning mode combined with the ion switching technology in positive and negative ion switching mode. The developed isotope-labelled internal standard-based UPLC-MS/MS method exhibited an approving linearity (r≥0.9984), high sensitivity (limit of detection in the range of 0.015-30.05μg/kg), acceptable precision (RSDs ≤6.3%) and good recovery (76.0-116.0%) for 11 analytes, respectively. Ten batches of real lotus seed samples were tested, and three batches out of which were contaminated with AFB1 , FB2 , T-2 and ZEN. AFB1 showed the highest occurrence rate (30%) with contents of 10.50 and 8.32μg/kg in two samples over the official limit (5.0μg/kg). The monitoring of multiclass mycotoxins in Chinese herbal medicines is in great urgency to ensure the security of consumers. The proposed method could be further utilized for simple, sensitive and rapid detection of more mycotoxins in other complex matrices to compensate for matrix effects.

The development characteristics of the discontinuous leader under the positive switching impulse with low rate of voltage rising

Discontinuous leader development is the most important discharge process under the application of the switching impulse voltage with the low rate of voltage rising, which is of great significance to study the external insulation characteristics of ultra-high voltage (UHV) large scale air gap. Based on the CMOS high-speed camera, a discharge test with different operating impulse voltage is carried out by constructing a comprehensive observation platform of rod-plate air gap discharge, and a clear discontinuous leader development process picture is captured. Moreover, the leader current, injection charge and leader channel unit length charge, and their characteristics of the change trend are also obtained. Further analysis based on the experimental results shows that the discontinuous leader development under the action of the impulse voltage with low rate of voltage rising has two different laws. Finally, this paper uses the thermodynamic equation, combined with the test results, the channel temperature changes in the discontinuous leader development stagnation stage were calculated. The results show that the leader channel temperature is still greater than 1500 K in the hundreds of microsecond time scales in the leader stagnation stage, and the subsequent leader can continue to develop on the original leader channel.

PENGARUH SERVICE QUALITY TERHADAP SWITCHING BEHAVIOR PENGGUNA SIM CARD TELKOMSEL

The aims of this study are to investigate the effect of service quality and innovationon switching behavior. Colleger of Syiah Kuala University as the consumers ofSubscriber Identity Module card Telkomsel is taken as a sample in this study. Themethod of this study employed questionnairs as an instrument. Total sampling is appliedas the study’s proportional technique. Hierarchical Linear Modelling methodsof analysis are used to determine the influence of the variables involved. The resultof this study indicates that service quality have positive effect on switching behavior,service quality have positive effect on innovation, and innovation has positive effecton switching behavior. The study also shows that innovation influential significantlyagainst service quality nor against switching behavior. In addition abtained resultsthat innovation has partial mediated the effect of service quality to impulse switchingbehavior.

Younger and older trust in a crisis situation

PurposeThe purpose of this paper is to analyze consumer trust during a financial crisis, studying its antecedents and consequences. The perceptions of older and younger consumers are also compared.Design/methodology/approachThe theoretical model of trust formation is tested on a random sample of 634 individuals from the three largest Spanish cities, Madrid, Barcelona and Valencia, in a period of economic crisis. Structural equation models were used to verify the global hypothesized relationships. Additionally, the total sample was divided into two groups (younger and older consumers) in order to test the moderating effect of age in the proposed relationships.FindingsIn a period of financial crisis, older consumers’ trust is protected by an emotional and experiential shield from the effects of negative news in the surrounding environment. In contrast, trust, although important, is not the core variable for the younger segment, whose preferences are the consequence of a broad range of cognitive and emotional variables.Research limitations/implicationsThis research was carried out on financial services. Emotional, relational and experience-linked variables acquire greater importance as the individual gets older, in contrast to more cognitive evaluations. The difference between the younger and the older segments is that the cornerstone of older consumers’ attitudinal loyalty is trust, whereas for younger people, it is positive switching costs or rewards. Further research on the proposed conceptual model across different industries and countries is needed to determine the generalizability and consistency of the findings from this study.Practical implicationsThis paper has significant managerial implications. The authors believe that the best strategy for a bank during a period of crisis is to follow a customer-friendly orientation, as in the case of banks that took a long-term vision to look after their brand image. The study draws banking companies’ attention to the importance of using age as a segmentation criterion.Originality/valueBased on the life-course paradigm, a theoretical model of trust formation is performed. In a period of economic crisis, trust becomes the key variable in determining older consumers’ preferences.