The Predicting Model of E-commerce Site Based on the Ideas of Curve Fitting

AbstractOn the basis of the idea of the second multiplication curve fitting, the number and scale of Chinese E-commerce site is analyzed. A preventing increase model is introduced in this paper, and the model parameters are solved by the software of Matlab. The validity of the preventing increase model is confirmed though the numerical experiment. The experimental results show that the precision of preventing increase model is ideal

Local residual stress evolution of highly irregular thermally grown oxide layer in thermal barrier coatings

Local residual stress in thermally grown oxide (TGO) layers is the primary cause of failure of thermal barrier coating (TBC) systems, especially TBCs prepared by air plasma spray (APS) with a highly irregular TGO. Herein, the distribution of residual stress and the evolution of the irregular TGO layer in APS TBCs were investigated as a function of oxidation time. The stress was measured from cross-sectional micrographs and converted to the actual stress inside the coatings before sectioning. The TGO exhibited significant inhomogeneity at different locations. Stress conversion occurred across the TGO thickness; the layer near the yttria-stabilised zirconia (YSZ) component exhibited compressive stress, whereas that along the bond coat was under tensile stress. The evolution of the compressive stress is also discussed. These analyses may provide a better understanding of the mechanism of APS TBCs

Electrical-thermal coupling characteristics of pre-insertion resistors in AC filter circuit breaker for UHV grid

The ultra-high voltage (UHV) AC/DC grid can provide a platform for sustainable power worldwide. To improve the bus voltage quality of the UHV AC system, AC filters are frequently switched into the UHV grid through circuit breakers with pre-insertion resistors. The pre-insertion resistors suppress inrush currents and operate over-voltage during switching. In this paper, we establish a macro and micro model of the pre-insertion resistor based on its temperature coefficient and micro-morphology. We simulate and analyze its electric-thermal coupling characteristics under standard closing and short-circuit faults. After the simulation model and physical comparison analysis, we find that under a usual closing surge, the electric field distribution of the pre-insertion resistor is uniform and undergoes a slight rise in temperature. However, under a short circuit fault, the temperature rise is drastic and exceeds the maximum allowable temperature, causing glassy melt in some parts of the resistor. Considering the volume ratio of each component of the resistor, a two-dimensional cross-sectional simulation model of the resistor is established to simulate the electric-thermal characteristics of the microstructure of the resistor, and insinuates that the current is concentrated in the carbon channel. That is mainly due to the uneven distribution of carbon material and may lead the local temperature to exceed the maximum allowable temperature and damage the resistor

Knockdown of a novel lincRNA AATBC suppresses proliferation and induces apoptosis in bladder cancer

Long intergenic noncoding RNAs (lincRNAs) play important roles in regulating various biological processes in cancer, including proliferation and apoptosis. However, the roles of lincRNAs in bladder cancer remain elusive. In this study, we identified a novel lincRNA, which we termed AATBC. We found that AATBC was overexpressed in bladder cancer patient tissues and positively correlated with tumor grade and pT stage. We also found that inhibition of AATBC resulted in cell proliferation arrest through G1 cell cycle mediated by cyclin D1, CDK4, p18 and phosphorylated Rb. In addition, inhibition of AATBC induced cell apoptosis through the intrinsic apoptosis signaling pathway, as evidenced by the activation of caspase-9 and caspase-3. The investigation for the signaling pathway revealed that the apoptosis following AATBC knockdown was mediated by activation of phosphorylated JNK and suppression of NRF2. Furthermore, JNK inhibitor SP600125 could attenuate the apoptotic effect achieved by AATBC knockdown, confirming the involvement of JNK signaling in the induced apoptosis. Moreover, mouse xenograft model revealed that knockdown of AATBC led to suppress tumorigenesis in vivo. Taken together, our study indicated that AATBC might play a critical role in pro-proliferation and anti-apoptosis in bladder cancer by regulating cell cycle, intrinsic apoptosis signaling, JNK signaling and NRF2. AATBC could be a potential therapeutic target and molecular biomarker for bladder cancer

On the sequential test per MIL-STD-781 and new, more efficient test plans.

The sequential probability ratio test is an efficient test procedure compared to the fixed sample size test procedure in the sense that it minimizes the average sample size needed for terminating the experiment at the two specified hypotheses, i.e., at H₀: θ = θ₀ and H₁: θ = θ₁. However, this optimum property does not hold for the values of the testing parameter other than these two hypotheses, especially for those with values between these two. Also the estimation following a sequential test is considered to be difficult, and the usual maximum likelihood estimate is in general biased. The sequential test plans given in MIL-STD-781 do not meet their nominal test risk requirements and the truncation of these test plans is determined by the theory for a fixed sample size test. The contributions of this dissertation are: (1) The distribution of the successive sums of samples from a generalized sequential probability ratio test in the exponential case has been obtained. An exact analysis method for the generalized sequential probability ratio test has been developed as well as its FORTRAN programs based on this distribution. (2) A set of improved sequential probability ratio test plans for testing the mean for the exponential distribution has been established. The improved test plan can meet the test risk requirements exactly and can approximately minimize the maximum average waiting time. (3) The properties of the estimates after a sequential test have been investigated and a bias reduced estimate has been recommended. The general method for constructing the confidence interval after a sequential test has been studied and its existence and uniqueness have been proved in the exponential case. (4) Two modification to the Wald's sequential probability ratio test, the triangular test and the repeated significance test, in the exponential case have been also studied. The results show that the triangular test is very close to the optimal test in terms of minimizing the maximum average sample size, and a method for constructing the triangular test plan has been developed

Long-Term Failure Mechanisms of Thermal Barrier Coatings in Heavy-Duty Gas Turbines

Thermal barrier coatings serve as thermal insulation and antioxidants on the surfaces of hot components. Different from the frequent thermal cycles of aero-engines, a heavy-duty gas turbine experiences few thermal cycles and continuously operates with high-temperature gas over 8000 h. Correspondingly, their failure mechanisms are different. The long-term failure mechanisms of the thermal barrier coatings in heavy-duty gas turbines are much more important. In this work, two long-term failure mechanisms are reviewed, i.e., oxidation and diffusion. It is illustrated that the growth of a uniform mixed oxide layer and element diffusion in thermal barrier coatings are responsible for the changes in mechanical performance and failures. Moreover, the oxidation of bond coat and the interdiffusion of alloy elements can affect the distribution of elements in thermal barrier coatings and then change the phase component. In addition, according to the results, it is suggested that suppressing the growth rate of uniform mixed oxide and oxygen diffusion can further prolong the service life of thermal barrier coatings

Effects of communication style and culture on ability to accept recommendations from robots

The objective of this paper is to investigate the effects of communication styles and culture on people’s accepting recommendations from robots. The goal was to provide insight for culturally adaptive robot design. The independent variables were communication style (i.e. implicit or explicit), the participants’ cultural background (i.e. Chinese or German), and the robot’s language (i.e. native language and English for Chinese and German subjects). A laboratory experiment was conducted with 16 Chinese and 16 German college students. Basic descriptive statistics and t-test are used for biographical information analysis; reliability test is used for questionnaire; MANOVA and non-parametric test are used for testing the hypotheses. The results showed that the Chinese participants preferred an implicit communication style than German participants. Chinese participants evaluated the robots as being more likable, trustworthy, and credible, and were more likely to accept the implicit recommendations. The German participants evaluated the robots as being less likable, trustworthy, and credible, and were less inclined to accept implicit recommendations