مرجان رجبی

The aim of this study is to propose a model to determine and explain the antecedents and consequences of online customer experience in social media.

This research was conducted using a mixed-methods approach. In the qualitative section, data were collected through semi-structured interviews with 20 experts in the field of digital marketing and analyzed using content analysis and MAXQDA software. In the quantitative section, a questionnaire based on the qualitative model was distributed among 384 social media users who were customers of online stores. The quantitative data were analyzed using SPSS 24 and Smart PLS 3 software.

The results showed that environmental factors, customer retention, product purchase, customer-centricity, and product significantly impacted the online customer experience, while ease-of-use did not have a significant effect. Additionally, the model developed in the qualitative section successfully explained the relationships between the variables and was deemed suitable for practical application in digital businesses.

This study demonstrated that various factors such as environment, customer-centricity, and purchase processes play a crucial role in enhancing the online customer experience. Organizations can improve customer experience by focusing on these factors and refining their digital strategies, which in turn can increase customer satisfaction and loyalty. The findings also highlight the importance of personalized services and engagement with customers in digital platforms.

 Use of natural ingredients is a safe efficient approach to overcome various diseases. Encapsulated ginger extract has shown improved physicochemical characterizations, compared with that, the ginger extract has. In this study, a natural system integrated with ginger bioactive compounds (6-gingerol) and green microalgae of Chlorella vulgaris was reported to increase bioactive compounds medicinal effectiveness and introduce a novel food supplement.

 First, nanoparticles of microalgae were produced using ball-milling technique. Ethanolic ginger extract, loaded on microalga nanoparticles, was investigated at various pH values (2-7.4) to effectively release the active agents. Various analytical techniques (e.g., Fourier transform infrared, thermogravimetric analyses) were used to characterize the nanocomposite and investigate its anticancer and antimicrobial effects.

 Dynamic light scattering showed a medium size of 20.9 nm for the microalga nanoparticles. The release assay of ginger polyphenols showed a releasing process controlled by the pH. Fourier transform infrared, thermogravimetric analysis and differential thermal analysis revealed adsorption of ginger extract on nano Chlorella vulgaris surface. Moreover, 2,2-diphenyl-picrylhydrazyl bioassay results on the nanocomposite (GE@nano C.v) verified its significant antioxidant, antibacterial and anticancer activities. The nanocomposite has the minimum inhibitory effect on human breast adenocarcinoma cells and bacterial growth at 1 and 6.25 mg ml-1 concentrations, respectively. In brief, adsorption of ginger extract on the microalga nanoparticle surfaces enhanced physical and chemical characteristics of the ginger extract, compared to its free form. Bioactive compounds in Chlorella vulgaris and ginger extract strengthen their reported activities. Furthermore, microalgal nanoparticles could act as a safe carrier for the controlled release of 6-gingerol in addition to their nutraceutical characteristics.

Flash sintering is one of the latest sintering processes of ceramics, which has recently attracted the attention of researchers due to its high sintering speed and significant energy reduction. An essential feature of successful flash is negative temperature coefficient (NTC) semiconductor behavior. In this research, the flash sinter process of ceramic varistor based on ZnO-Bi2O3-Sb2O3 (ZBS) has been investigated and the effect of changing the molar ratio of the compound and adding cobalt oxide (Co3O4) as an increasing factor of electrical conductivity has been studied. The optimal conditions of the flash process were determined by applying different values ​​of electric field and current density, and finally, the electric field was 300 V/cm and the current density was 100 mA/mm2. The structural investigation and identification of the formed phases have been done by scanning electron microscope and X-ray diffraction, respectively. The electrical characteristics of the varistor (non-linear coefficient, breakdown voltage, and leakage current) were measured under the DC electric field. The density of the sample with cobalt oxide additive was 97% of the theoretical density. SEM results indicate the formation of varistor microstructure with an average grain size of 3 microns. By determining the electrical characteristics, the behavior of the varistor was observed, in which the nonlinear coefficient was 22, the threshold voltage was 4500 V/cm and the leakage current density was 50 μA/mm2.

In this study, the amorphous carbon thin films were deposited by ion beam sputtering deposition method on the glass and Ni–Cu alloy substrates. The structural evolution of amorphous carbon and its correlation with the kinetic energy of carbon atoms during the growth of thin film was investigated. The effect of substrate material, deposition temperature, and ion beam energy on the structural changes were examined. Raman spectroscopy indicated a structural transition from amorphous carbon to diamond-like amorphous carbon (DLC) due to an increase in deposition temperature up to 100°C and ion beam energy from 2 keV to 5 keV. The size of graphite crystallites with sp2 bonds (La) were smaller than 1 nm in the amorphous carbon layers deposited on Ni-Cu alloy. The results of residual stress calculation using X-ray diffractometer (XRD) analysis revealed a decreasing trend in the tensile residual stress values of the amorphous carbon thin films with increasing the ion beam energy.

The growth kinetic of amorphous carbon (a-C) thin films was investigated in the relation to the surface morphology and structural transformations. The a-C thin films were deposited by ion beam sputtering technique on the glass substrate. According to Avrami's model, the growth at the thickness above 56 nm (after 900 s deposition) is two-dimensional and the proposed equation for investigating about the growth process of amorphous carbon thin film in the present study is as follows: V=1-exp⁡(-2×〖10〗^(-7) t^2 ). Transformations of the thickness is similar to proposed Avrami's model follow a characteristic s-shaped, or sigmoidal, profile during deposition time from 300s to 4500s, where the transformation rates are low at the beginning and the end of the transformation but rapid in between. Surface roughness and structural transformation depend on the film thickness. Raman spectra showed the maximum displacement in G peak position created in the film thickness equal 360 nm with the reduction of the growth rate. The ID/IG ratio, the size of graphite crystallites with sp2 bonds (La) and the roughness of this layer is equal to 1.2, 1.48 nm and 20.39±4.8 nm, respectively.

In this study, the graphitic amorphous carbon (g-C) thin films were deposited by the ion beam sputtering deposition (IBSD) technique on glass substrates. The effect of ion beam energy on the optical and structural properties of thin films was investigated in the wide range from 1.8 keV to 5 keV. The results of investigation about optical and structural properties using UV-visible spectroscopy and Raman spectroscopy respectively showed a direct correlation between structural and physical developments. Raman spectra indicated a structural transition from graphite to nano-crystalline graphite phase. The values of ID/IG ratio, optical transparency and optical band gap depend on the ion beam energy; all of them increased by increasing argon ion beam energy from 3 keV, which is associated with a decrease in the film thickness. Furthermore, the sheet resistance of the samples was measured by the four-point probe (FPP) followed similar trends of these structural properties. According to Tauc equation the maximum optical band gap was equal to 3.75 eV by the graphite crystallites (with sp2 bands (La )) equal to 5 nm in amorphous carbon thin film deposited with the highest argon ion beam energy of 5 keV.

The advent of new technology in recent years has facilitated the production of high dimension data. In these data we need evaluating more than one assumption.  Multiple testing can be used for the collection of assumptions that are simultaneously tested and controlled the rate of family wise error that is the most critical issue in such tests. In this report, the authors apply Sidak and Stepwise strategies for controlling family wise error rate in detecting outlier profiles and comparing to each other. Considering our simulation results, the performance of such methods are compared using the parametric bootstrap snd by applying on real data in dataset illustrate the implementation of the proposed methods.

This paper studies the structural, optical and ultraviolet photodetection of rutile titanium dioxide nanorods (TiO2). A regular array of relatively vertically aligned TiO2 nanorods has been grown on fluorine doped tin oxide (FTO) coated glass substrate by using one step hydrothermal synthesis method. The morphology and crystal structure were studied by scanning electron microscopy and X- ray diffraction, respectively. Photoluminescence (PL) and diffuse reflectance spectroscopy were used as experimental methods for band gap energy estimation of nanostructures. The room temperature Photoluminescence spectra were measured under two different excitation energies of 4.13 and 3.82 eV. The results indicate the dependence of the PL spectrum to excitation energy. Thus, the band gap energy of nanorods is approximately equal to 3.04 eV and observed in the PL spectrum under 4.13 eV excitation energy. Comparing the applied reported methods for calculating the band gap energy by using diffuse reflectance spectra and Kubelka- Munk method shows that the most relevance to PL data exist with application of  equation. The ultraviolet photodetection performance of TiO2 nanorods in  Au/TiO2/Au device structure under 365 nm illumination is evaluated by determining resposivity, sensivity and rise and decay tims.

Ni-Cu (70.4-29.6 ; wt%) alloy was prepared by a Vacuum Arc Remelting (VAR) furnace and the effect of thermal treatment on structure and Curie temperature was investigated. The results of Inductively Coupled Plasma (ICP) and EDS analysis showed that specimens with 4 times remelting were homogenized. The Curie temperature of alloy that measured by vibrating sample magnetometry (VSM) under condition of slow cooling across from order-disorder transition of alloy was higher than specimens quenched from recrystallization temperature. Curie temperature (TC) of alloy that quenched after melting was 60 ͦ C ,TC of sample that annealed in 1000 ͦ C for 24 hours then quenched in water was 40 ͦ C and sample that after annealing twice heated up to 70 ͦ C was 45.5 °C .
The d-spacing of the specimen without heat treatment, calculated by X-Ray Diffraction, had a little increase due to clustering. In addition, the surface morphology by optical microscope confirmed this behavior of Cu–Ni alloys in the different heat treatment.

In this study the effect of substrate temperature (from room temperature (RT) to 400°C) on the sructural and physical properties of cabon thin films were investigated. The films were prepared by ion beam sputtering deposition technique on glass substrate. Optical and structural properties were studied by UV-visible spectroscopy, Raman spectroscopy and atomic force microscopy, respectively. The results showed that optical transparency decreased with the increase in the substrate temperature. Raman spectra indicated a structural transition from amorphous to graphite-like phase by increasing temperatures since in the spectra; D peak disappeared in the layer at the substrate temperature of 400°C. The result of sheet resistance and the optical band gap showed the reduction trend by the increase in the substrate temperature from 100 to 400°C. However the enhancement of the surface roughness with the substrate temperature was observed. In the layer prepered with the substrate temperature equal to 100 °C , a minimum size of the graphite crystallites (with sp2 bands (La)) was equal to 0.36 nm and a maximum optical band gap was equal to 3 eV.