Search results

The purpose of this paper is to study the effect of doping, annealing temperature and visible optical excitation on CuO-ZnO nanocomposites’ acetone sensing properties and introduce an attractive candidate for acetone detection at about room temperature.

ZnO nanoparticles doped with CuO were prepared by sol-gel method, and the structure and morphology were characterized via X-ray diffraction, scanning electron microscope, energy dispersive spectroscopy and Brunauer-Emmett-Teller. The photoelectric responses of CuO-ZnO nanocomposites to cetone under the irradiation of visible light were investigated at about 30°C. The photoelectric response mechanism was also discussed with the model of double Schottky.

The doping of CuO enhanced performance of ZnO nanoparticles in terms of the photoelectric responses and the gas response and selectivity to acetone of ZnO nanoparticles, in addition, decreasing the operating temperature to about 30ºC. The optimum performance was obtained by 4.17% CuO-ZnO nanocomposites. Even at the operating temperature, about 30ºC, the response to 1,000 ppm acetone was significantly increased to 579.24 under the visible light irradiation.

The sensor fabricated by 4.17% CuO-ZnO nanocomposites exhibited excellent acetone-sensing characteristics at about 30ºC. It is promising to be applied in low power and miniature acetone gas sensors.

In the present research, a new nanocomposite material of CuO-ZnO was prepared by Sol-gel method. The optimum gas sensing properties to acetone were obtained by 4.17% CuO-ZnO nanocomposites at about 30ºC operating temperature when it was irradiated by visible light with the wavelength more than 420 nm.

In some three-dimensional (3D) printing application scenarios, e.g., model manufacture, it is necessary to print large-sized objects. However, it is impossible to implement large-size 3D printing using a single projector in digital light processing (DLP)-based mask projection 3D printing because of the limitations of the digital micromirror device chips.

A multi-projector DLP with energy homogenization (EHMP-DLP) scheme is proposed for large-size 3D printing. First, a large-area printing plane is established by tiling multiple projectors. Second, the projector set’s tiling pattern is obtained automatically, and the maximum printable plane is determined. Third, the energy is homogenized across the entire printable plane by adjusting gray levels of the images input into the projectors. Finally, slices are automatically segmented based on the tiling pattern of the projector set, and the gray levels of these slices are reassigned based on the images of the corresponding projectors.

Large-area high-intensity projection for mask projection 3D printing can be performed by tiling multiple DLP projectors. The tiled projector output energies can be homogenized by adjusting the images of the projectors. Uniform ultraviolet energy is important for high-quality printing.

A prototype device is constructed using two projectors. The printable area becomes 140 × 210 mm from the original 140 × 110 mm.

The proposed EHMP-DLP scheme enables 3D printing of large-size objects with linearly increasing printing times and high printing precision. A device was established using two projectors to practice the scheme and can easily be extended to larger sizes by using more projectors.

The purpose of this paper is to investigate how different types of the village relationship influence different types of public goods provision in rural China.

The three components (clan-based relationship, neighborhood relationship and external relationship) were derived by employing factor analysis. The simultaneous discrete choice model was used to estimate the influence of these components on public goods provision, using the survey data from the China Household Income Project conducted in 2007.

The findings indicate that considering different components of village relationship allows for a better understanding of the public good provision. The results indicate that the neighborhood relationship has a significantly positive effect on rural public goods provision, particularly on water conservancy and irrigation, while the external relationship has a significantly positive effect on all types of public goods.

Local public goods provision is the core of the new rural construction in China. These findings imply that relationship in villages plays a vital role in the provision of public goods and is necessary in the construction of the new harmonious countryside in China. The results also have implications for rural public goods provision in other developing countries.

To the best of our knowledge, this is the first study to quantitatively model the impact of different relationships on public goods provision at the rural level. A consideration of the different components in village relationship allows for a more precise understanding of the pubic goods provision in the village.

Through the scientific and reasonable evaluation of the site selection of the emergency material reserve, the optimal site selection scheme is found, which provides reference for the future emergency decision-making research.

In this paper, we have chosen three primary indicators and twelve secondary indicators to construct an assessment framework for the determination of suitable locations for storing emergency material reserves. By mean of the improved entropy weight-order relationship weight determination method, the evaluation model of kullback leibler-technique for order preference by similarity to an ideal solution (KL-TOPSIS) emergency material reserve location based on relative entropy is established. On this basis, 10 regional storage sites in Beijing are selected for evaluation.

The results show that the evaluation model of the location of emergency material reserve not only respects the objective knowledge, but also considers the subjective information of the experts, which makes the ranking result of the location of the emergency material reserve more accurate and reliable.

Firstly, the modification factor is added to the calculation formula of traditional entropy weight method to complete the improvement of entropy weight method. Secondly, the order relation analysis method is used to assign subjective weights to the indicators. The principle of minimum information entropy is introduced to determine the comprehensive weight of the index. Finally, KL distance and TOPSIS method are combined to determine the relative entropy and proximity degree of alternative solutions and positive and negative ideal solutions, and the scientific and effective of the method is proved by case study.

The hosts' third-party certifications in the sharing accommodation platforms have largely overlooked how the provision of such certification information could facilitate the trust-building process and subsequently influence consumers' purchase intention. Adopting an institution-based trust perspective, the authors differentiate various types of hosts' certification information (i.e. financial certification and social certification) and examine their role in the trust-building process between the hosts and the customers on sharing accommodation platforms.

This study uses the property-month level data of Airbnb Beijing from January 2019 to June 2020. Econometric analyses are adopted to evaluate the impact of institution-based trust on consumers' purchase intention. Specifically, the ordinary least square is used to testify the relationship between institution-based trust and purchase intention.

The empirical results show that the information on institution-based trust increases the likelihood that customers would reach purchase decisions. More importantly, results show that both financial certification and social certification affect consumers' purchase intention. The results further show that listings' attributes moderate the relationship between institution-based trust and customer purchase intention. Moreover, the authors find that “Superhost” and “Experience” positively moderate such relationships.

This paper confirms that the host certification fosters institution-based trust and reveals the impact of hosts' certification on consumers' purchase intentions. This study is among one of the first studies to incorporate institution-based trust into the trust formation on the sharing economy platform, which can improve the understanding of trust in the sharing economy context. The authors emphasize the importance of trust types on sharing economy platforms.

In response to the 2008 financial crisis, the performance of the Chinese construction industry seems to be more successful, especially in total factor productivity growth (TFPG) and its contribution (TFPGC). Hence, the purpose of this paper is to investigate and reveal the potential successful lessons in this regard.

This study is conducted innovatively based on a special comparative analysis of TFPG and TFPGC between pre- and post-2008 financial crisis. Solow Residual Approach is used to measure TFPG and TFPGC for the period 2002–2016. Given that the crisis hit China at the end of 2008, the pre-2008 financial crisis period is from 2002 to 2008, and the post-2008 financial crisis period is limited to 2009–2016.

The results indicate that the industry indeed has better performance in promoting TFPG and TFPGC, TFP thus achieved significant accumulative growth before and after the crisis. However, from an evolutionary perspective, both TFPG and TFPGC presented an overall downward trend from before the crisis to after the crisis. Further, the game between the centrally planned economy and the market-oriented economy was identified and revealed as the essential reason behind the evolution of TFPG and TFPGC.

Some valuable lessons for policies and practices in promoting TFPG and TFPGC were summarized and learned from the Chinese experience, such as reducing administrative intervention and making the construction market play a decisive role.

This study provides some new empirical evidence to enrich the overall body of knowledge on growth theory, especially in promoting TFPG and TFPGC.