275 research outputs found
An Empirical Study of China-Australia Bilateral Trade Potential Based on Gravity Model
Based on the use of trade integration index and gravity model, this paper uses the bilateral goods trade data between China and Australia from 2000 to 2019 to analyze the trade status, trade complementarity and trade potential between China and Australia. The results of the study show that the trade scale, trade complementarity and trade potential between China and Australia are constantly expanding. However, from the perspective of trade balance, China has always been in the position of a deficit country, and the deficit is getting larger and larger, especially in terms of primary products. Judging from the trade integration index, Chinaās trade integration with Australia generally shows an upward trend, indicating that the trade dependence between China and Australia is gradually increasing. Judging from the results of the trade potential analysis, the trade potential between the two countries has not been fully realized, and there is still much room for improvement in bilateral trade relations
Enterpriseās Strategies to Deal with Epidemic Crisis Based on Super-Dynamic Capability Theory
In this paper, the supply chain management risks arising from 2019-novel coronavirus (hereinafter referred to as āCOVID-19ā) outbreak was proposed, and they were further analyzed from three main aspects such as change in demand conditions of domestic customers, change in domestic supply market, impact on domestic logistics industry. Besides, multiple feasible strategies for coping with such epidemic situation were proposed for enterprises based on the super-dynamic capability theory. The research in this paper has powerful theoretical value and practical significance for the current development of enterprises, especially the reorganization of enterprises under the current epidemic crisis in China
Development Status and Business Solution of Ultra-high Pressure Food
Ultra-high pressure food processing technology refers to the technology of sterilizing food under thousands of atmospheric pressure without destroying the properties of food raw materials. Japan is a world leader in HPP technology. Significant achievements have been made in experimental equipment, production equipment, processing, sterilization and preservation of ultra-high pressure technology. Almost all natural, safe and healthy HPP food jams and fruit juices have been commercialized. Germany, the United States, France, the United Kingdom and other countries are also unwilling to fall behind, they are scrambling to carry out research on ultra-high voltage technology and have achieved industrialization results.Chinaās research on food ultra-high pressure technology started late. After nearly ten years of technical digestion and research, the research results have been achieved in stages, but there is still a large gap compared with developed countries. This article outlines the application of HPP technology in food processing, briefly analyzes the development of HPP food technology in China today, and establishes a cold chain supply chain model to identify problems and propose certain countermeasures, with a view to addressing HPP technology in food and chemicals industry
Application-Driven AI Paradigm for Human Action Recognition
Human action recognition in computer vision has been widely studied in recent
years. However, most algorithms consider only certain action specially with
even high computational cost. That is not suitable for practical applications
with multiple actions to be identified with low computational cost. To meet
various application scenarios, this paper presents a unified human action
recognition framework composed of two modules, i.e., multi-form human detection
and corresponding action classification. Among them, an open-source dataset is
constructed to train a multi-form human detection model that distinguishes a
human being's whole body, upper body or part body, and the followed action
classification model is adopted to recognize such action as falling, sleeping
or on-duty, etc. Some experimental results show that the unified framework is
effective for various application scenarios. It is expected to be a new
application-driven AI paradigm for human action recognition
Pronounced ductility in CuZrAl ternary bulk metallic glass composites with optimized microstructure through melt adjustment
Microstructures and mechanical properties of as-cast Cu47.5Zr47.5Al5 bulk metallic
glass composites are optimized by appropriate remelting treatment of master
alloys. With increasing remelting time, the alloys exhibit homogenized size and
distribution of in situ formed B2 CuZr crystals. Pronounced tensile ductility of
ā¼13.6% and work-hardening ability are obtained for the composite with optimized
microstructure. The effect of remelting treatment is attributed to the suppressed heterogeneous
nucleation and growth of the crystalline phase from undercooled liquid,
which may originate from the dissolution of oxides and nitrides as well as from
the micro-scale homogenization of the melt
Effect of suction chamber baffles on pressure fluctuations in a low specific speed centrifugal pump
In order to study the effect of suction chamber baffles on hydraulic performance and unsteady characteristics in a low specific speed centrifugal pump, a model pump was design with enlarging flow mothed and four schemes of suction baffle, including no baffle (scheme 0), only one baffle in the suction (scheme 1), two baffles (scheme 2) and three baffles in the suction (scheme 3), were considered. Commercial code FLUENT was applied to simulate the flow of the pump. RNG k-Īµ turbulence model was adopted to handle with the turbulent flows in the pump. The sliding mesh technique was applied to take into account the impeller-volute interaction. Based on the simulation results, the hydraulic performance and pressure fluctuations were obtained and analyzed in detail. The head value of no baffle in the suction (scheme 0) is lower than that with baffles in the suction (scheme 1, schemeĀ 2, schemeĀ 3) at each condition point. Hump point in scheme 0 is at Ļ= 0.00596 (1.2 times Qo). The hump point in scheme 1, scheme 2, schemeĀ 3 is at 0.8Qo, 1.0Qo, 1.0Qo, respectively. The Īµ value of scheme 1 is the smallest and that of scheme 0 is the largest in the four schemes. Six wave troughs are observed clearly at each monitoring point as the impeller rotates in a circle. Each time the impeller is turned 10 degrees, there are six obvious troughs around the impeller. With the rotation of the impeller, peak value of pressure fluctuations at blade passing frequency (BPF) is gradually decrease. At low flow (Ļ=Ā 0.002383), the main frequency of pressure fluctuation at P36 and P1 under scheme 0, scheme 2 and scheme 3 is 295Ā Hz, which is corresponding to BPF. The pressure fluctuation levels are decreased by ā2.72 %, ā2.13Ā %, and ā2.21Ā % respectively when the number of baffle in the suction is one, two, three, respectively. And decrease rate of pressure fluctuation (āCp) on scheme 1 is maximum. It indicates that Adding baffles to the suction chamber is beneficial to reduce the amplitude of pressure pulsation at BPF in the volute. The best number of baffles in the suction is one. Based on scheme 1 simulation results, the prototype was manufactured and the performance experiments were carried out. A good agreement of the head and efficiency between numerical results and experimental results are observed
Chip-Scale, Sub-Hz Fundamental Sub-kHz Integral Linewidth 780 nm Laser through Self-Injection-Locking a Fabry-P\'erot laser to an Ultra-High Q Integrated Resonator
Today's state of the art precision experiments in quantum, gravimetry,
navigation, time keeping, and fundamental science have strict requirements on
the level and spectral distribution of laser frequency noise. For example, the
laser interaction with atoms and qubits requires ultra-low frequency noise at
multiple offset frequencies due to hyperfine atomic transitions, motional
sidebands, and fast pulse sequencing. Chip-scale integration of lasers that
meet these requirements is essential for reliability, low-cost, and weight.
Here, we demonstrate a significant advancement in atomic precision light
sources by realizing a chip-scale, low-cost, 780 nm laser for rubidium atom
applications with record-low 640 mHz (white noise floor at 0.2 Hz/Hz)
fundamental and 732 Hz integral linewidths and a frequency noise that is
multiple orders of magnitude lower than previous hybrid and heterogeneous
self-injection locked 780 nm lasers and lower noise than bulk microresonator
implementations. The laser is a Fabry-P\'erot laser diode self-injection locked
to an ultra-high Q photonic integrated silicon nitride resonator. This
performance is enabled by a 145 million resonator Q with a 30 dB extinction
ratio, the highest Q at 780 nm, to the best of our knowledge. We analyze the
impact of our frequency noise on specific atomic applications including atomic
frequency references, Rydberg quantum gates, and cold atom gravimeters. The
photonic integrated resonator is fabricated using a CMOS foundry-compatible,
wafer-scale process, with demonstrated integration of other components showing
promise for a full system-on-a-chip. This performance is scalable to other
visible atomic wavelengths, opening the door to a variety of transitions across
many atomic species and enabling low-power, compact, ultra-low noise lasers
impacting applications including quantum sensing, computing, clocks and more
Angular deviation and diffraction efficiency of Littrow-configuration ECDL for three-dimensional diffraction
We consider in this paper the angular deviation and diffraction efficiency of
the reflection gratings in Littrow-configuration for applications of external
cavity diode laser (ECDL) using the rigorous coupled-wave analysis (RCWA)
method. We consider the three-dimensional diffraction case in general, where
the incidence plane is un-parallel with the grating vector (i.e. conical
diffraction). The angular tolerance of arbitrary gratings under plane and
conical diffraction are thus derived and presented. A typical blazed grating is
chosen as an example to calculate its diffraction efficiency (DE) using RCWA.
{Furthermore}, we point out that the angular tolerance and reflection
efficiency can be improved if the appropriate parameter settings are selected
for Littrow-configuration ECDL, including incidence angle, diffraction order,
grating period and blazed angle. Otherwise, a tiny slanting angle of the
grating vector deviated from the incidence plane will {deviate the feedback
light away from} entering the LD-chip and halt laser oscillation in the
external cavity. Finally, a general rule for the parameter settings in
Littrow-configuration is provided as a benchmark.Comment: 9 pages,11 figure
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