Search results

Public crisis often generates new knowledge that should be incorporated into a government’s macro-control to ensure the relief supply. From the perspective of public crisis knowledge management, the Chinese system of Government relief supplies can be considered as a special case of the knowledge system. This paper aims to investigate the supply and production mechanism of relief goods and explore the advantages of the Chinese system when a sudden public crisis occurs.

Under the Chinese system, the authors construct a relief supply chain model consisting of the Chinese Government, one manufacturer and one supplier, where the supplier has no capital constraints. Given the demand for relief goods, the government purchases from the manufacturer with a guide price. Then, the manufacturer decides on its order quantity and offers a wholesale price to the supplier. The supplier has a random capacity and decides on the level of knowledge acquisition to improve its capacity.

The authors first obtain the analytical solution for the manufacturer to motivate a high level of knowledge acquisition from the supplier. Specifically, the manufacturer’s optimal order quantity is equal to the demand and the optimal wholesale price has a cost-plus form that reimburses the supplier for its production cost and knowledge-acquisition cost. Next, the authors derive the optimal guide price for the government, which should be set to subsidize the manufacturer with a proportion of the sourcing cost. Finally, the authors compare the Chinese system with the market mechanism where the supplier has capital constraints and confirm that the Chinese system is more beneficial to both the manufacturer and the government.

Quantitative research on the Chinese system of Government relief supplies is difficult to be conducted. This paper provides feasible and practical methods to quantify the benefits of the Chinese system. The results reveal that the Chinese system is an effective mechanism of public crisis knowledge management, which can be helpful to the government’s policy-making in practice.

To explore the economical and reasonable semi-rigid permeable base layer ratio, solve the problems caused by rainwater washing over the pavement base layer on the slope, improve its drainage function, improve the water stability and service life of the roadbed pavement and promote the application of semi-rigid permeable base layer materials in the construction of asphalt pavement in cold regions.

In this study, three semi-rigid base course materials were designed, the mechanical strength and drainage properties were tested and the effect and correlation of air voids on their performance indexes were analyzed.

It was found that increasing the cement content increased the strength but reduced the air voids and water permeability coefficient. The permeability performance of the sandless material was superior to the dense; the performance of the two sandless materials was basically the same when the cement content was 7%. Overall, the skeleton void (sand-containing) type gradation between the sandless and dense types is more suitable as permeable semi-rigid base material; its gradation is relatively continuous, with cement content? 4.5%, strength? 1.5 MPa, water permeability coefficient? 0.8 cm/s and voids of 18–20%.

The study of permeable semi-rigid base material with large air voids could help to solve the problems of water damage and freeze-thaw damage of the base layer of asphalt pavements in cold regions and ensure the comfort and durability of asphalt pavements while having good economic and social benefits.

The purpose of this study is to provide effective and environmental-friendly corrosion inhibitors derived from graphene oxide for Q235 steel.

Nontoxic and environment-friendly 4-aminobenzoic acid was used to functionalize graphene oxide via amidation and diazotization. The obtained amidation 4-aminobenzoic acid functionalized graphene oxide (PAGO) and diazotization 4-aminobenzoic acid functionalized graphene oxide (PDGO) were characterized by FTIR, Raman and TEM, while the inhibition efficiencies were analyzed by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PDP). Furthermore, theoretical inhibition efficiencies were investigated by density functional theory (DFT) approach.

At a concentration of 40 ppm, the maximum inhibition efficiency of PAGO and PDGO were 97.90% and 96.72% in EIS measurement, respectively, which were in accordance with PDP data. Moreover, experimental results were supported by DFT-based quantum chemical calculation.

Environmental-friendly PAGO and PDGO were synthesized successfully. The synthetic inhibitors exhibited excellent inhibition efficiencies in EIS and PDP measurements. Furthermore, a computational study using DFT supported the trend that PAGO was better inhibitor than PDGO.

The purpose of the present study is to develop a new numerical framework that can predict the supersonic base flow more accurately, including the development of axisymmetrically separated shear layer and recompression shock. To this end, two aspects are improved and combined, i.e. a newly self-adaptive turbulence eddy simulation (SATES) turbulence modeling method and a high-order discretization numerical scheme. Furthermore, the performance of the new numerical framework within a general-purpose PHengLEI software is assessed in detail.

Satisfactory prediction of the supersonic separated shear layer with unsteady wake flow is quite challenging. By using a unified turbulence model called SATES combining high-order accurate discretization numerical schemes, the present study first assesses the performance of newly developed SATES for supersonic axisymmetric separation flows. A high-order finite differencing-based compressible computational fluid dynamics (CFD) code called PHengLEI is developed and several different numerical schemes are used to investigate the effects on shock-turbulence interactions, which include the monotonic upstream-centered scheme for conservation laws (MUSCL), weighted compact nonlinear scheme (WCNS) and hybrid cell-edge and cell-node dissipative compact scheme (HDCS).

Compared with the available experimental data and the numerical predictions, the results of SATES by using high-order accurate WCNS or HDCS schemes agree better with the experiments than the results by using the MUSCL scheme. The WCNS and HDCS can also significantly improve the prediction of flow physics in terms of the instability of the annular shear layer and the evolution of the turbulent wake.

The small deviations in the recirculation region can be found between the present numerical results and experimental data, which could be caused by the inaccurate incoming boundary layer condition and compressible effects. Therefore, a proper incoming boundary layer condition with turbulent fluctuations and compressibility effects need to be considered to further improve the accuracy of simulations.

The present study evaluates a high-order discretization-based SATES turbulence model for supersonic separation flows, which is quite valuable for improving the calculation accuracy of aeronautics applications, especially in supersonic conditions.

For the first time, the newly developed SATES turbulence modeling method combining the high-order accurate WCNS or HDCS numerical schemes is implemented on the PHengLEI software and successfully applied for the simulations of supersonic separation flows, and satisfactory results are obtained. The unsteady evolutions of the supersonic annular shear layer are analyzed, and the hairpin vortex structures are found in the simulation.

The purpose of this paper is to present recent work designing a mechanical robotic hand for self‐adaptive grasping, human‐like appearance, which can be used in a humanoid robot. Conventional robotic devices are relatively complex, large, cumbersome and difficult to be installed in a humanoid robot arm. Under‐actuated robot hands use less motors to drive more rotating joints, thus to simplify the mechanical structure, decrease the volume and weight and finally lower the difficulty of control and the cost.

A novel under‐actuated finger mechanism is designed, which is based on a gear‐rack mechanism, spring constraint and an active sleeve middle phalanx. The principle analyses of its self‐adaptive grasp and end power grasping are given. A new multi‐fingered hand named as TH‐3R Hand is designed based on the finger.

The design finger mechanism can be used in a robotic hand to make the hand obtain more degrees of freedom (DOF) with fewer actuators, and good grasping function of shape adaptation, decrease the requirement of control system. TH‐3R Hand has five fingers, 15 DOF. All fingers are similar. TH‐3R Hand has many advantages: it is simple in structure, light in weight, easy to control and low in cost. TH‐3R Hand can passively adapt different shapes and sizes of the grasped object. Experimental studies have demonstrated the self‐adaptation in grasping of the finger.

The implication of this research is that under‐actuated robotic hands are appropriate for the missions of grasping different objects. The limitation of the research to date is that issues of sensors, control, and communication have not yet been addressed.

Key technologies of the under‐actuated finger and TH‐3R Hand, with self‐adaptive grasping, human‐like appearance and low‐cost lightweight, are feasible. These technologies have the potential to make a significant impact.

These results present a self‐adaptive under‐actuated grasp concept and a humanoid robotic hand with under‐actuated gear‐rack mechanism.

There are two opposite views about whether the Antitrust Law is conducive to the development of the economy. One view is that the Antitrust Law can restrain monopoly, maintain market competition and benefit economic growth. The other view is that the Antitrust Law inhibits innovation by monopolistic firms and fosters rent-seeking, which is bad for economic growth. To provide a possible perspective for clarifying the controversy, this paper aims to answer the following two questions: first, will the Antitrust Law inhibit corporate innovation? Second, does the antitrust enforcement agency discriminate against private enterprises?

Based on the samples of A-share listed companies from 2003 to 2013, the authors use the implementation of China’s Antitrust Law in 2008 as a policy shock, take the monopoly enterprises in each industry as the treatment group and competitive enterprises as the control group, using the difference-in-differences method to test the impact of the implementation of the Antitrust Law on corporate innovation activities.

The results show that compared with competitive enterprises, the patent output of monopolistic enterprises was significantly reduced after the implementation of the Antitrust Law, which indicates that the Antitrust Law does inhibit the innovation activities of monopolistic enterprises. Further research finds that the innovation suppression effect of the Antitrust Law is more prominent in state-owned enterprises, which means that the government does not have “selective law enforcement” against private enterprises in the process of law enforcement. Therefore, the results provide evidence for the idea that government intervention is neutral.

First, the paper enriches and expands the research on the factors affecting corporate innovation from the perspective of market structure. Second, it enriches and expands relevant research on the consequences of implementing the Antitrust Law from the perspective of corporate innovation. Third, it not only provides the relevant empirical evidence for clarifying the dispute about the Antitrust Law but also is helpful to clarify whether the Chinese Government has “selective law enforcement” against private enterprises.

In order to solve the corrosion problems in the South China Sea, the purpose of this paper was to study the main influences of corrosion including temperature, H₂S content and corrosion inhibitor content in CO₂/H₂S oil field-produced water.

The corrosion products formed on the steel surface were observed and analyzed using scanning electron microscope (SEM) and X-ray diffraction (XRD).

The results indicate that temperature significantly influences the corrosion rate, which is a maximum at 70°C. The corrosion rate decreases as H₂S content increases which is less than 10 mg/L, but then it increases rapidly. The FeCO₃/Fe _x S _y protective film and a corrosion inhibition also were considered.

A mixture containing an imidazoline derivate and an organic amine can enhance the corrosion resistance of the corrosion product film.

A mixture containing an imidazoline derivate and an organic amine can enhance the corrosion product film corrosion resistance.

Imidazoline is one kind of environmentally safe agent which can be used in the ocean.

The corrosion can be controlled to a satisfactory extent in the presence of a mixture containing an imidazoline derivate and an organic amine.

With business and institution managers as the research subjects, 170 questionnaires were collected through mail and on‐the‐spot investigation. The results were: Forming time management effectiveness scale (TMES) including 11 inner factors; female manager is lower than male in total time management effectiveness; the total amount of male manager’s working time per week adds up to 52.489 hours and female manager’s 46.438 hours. Differences are seen in the amount and structure of working time as well as non‐working time. Finally, there is no significant difference between male and female managers in the serious degree of each wasting time factor but difference in sequence. The results here can serve as a reference for further studying and developing time management theory, for probing into the gender differences in time management, and will improve managers’ management practice.

By reviewing the related literature on the Jiaoshi Pinren Zhi (JPZ) system, this paper seeks to indicate that the implementation of JPZ not only has led to domestic brain drain and the imbalance of teachers' qualities between different areas and schools, but also has violated children's equal rights to education guaranteed by the Constitution and educational laws in PR China.

By analysing national policies and laws and some cases, the paper points out that the reforms on teachers' employment causes the imbalance of teachers' qualities between different areas and schools and it is against the principle of children's equal rights to education guaranteed by the Constitution and some educational laws in China.

Since the late 1980s, many reform initiatives have been launched in the context of the transition from planned economy to market economy in China.

The reforms on the teachers' employment system from “Tongyi Fenpei” (TF, a system of unified placement for all graduates) and the life‐time employment system to JPZ (a free contract employment system) is one of the important reform initiatives.

This paper aim to take the ship shaft stern bearing as the research object, and studies the influence of journal axial vibration on bearing dynamic characteristics under different misaligned angles and rotation speeds.

Computational fluid dynamics (CFD) and harmonic excitation method were used to build bearing unstable lubrication model, and the dynamic mesh technology was used in calculation.

The results indicate that journal axial vibration has a significant effect on bearing dynamic characteristics, like maximum oil film pressure, bearing stiffness and damping coefficients, and the effect is positively correlated with journal misaligned angle. The effect of shaft rotation speed and journal axial vibration on bearing dynamics characteristics are independent; they have no coupling. Bearing axial stiffness is mainly affected by the journal axial displacement, bearing axial damping is mainly affected by journal axial velocity and they are positively correlated with the misaligned angle. The influence of rotational speed on bearing axial stiffness and axial damping is not obvious.

This paper establishes the bearing dynamic model by CFD and harmonic excitation method with consideration of cavitation effect and analyzing the influence of journal axial vibration on the dynamic characteristics. The results are benefit to the design of ship propulsion shaft and the selection of stern bearing. Also, they are of great significance to improve the operation stability of the shaft bearing system and the vitality of the ship.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-11-2022-0337/