A fiber-optic Fabry-Perot (F-P) accelerometer with high resolution, high dynamic range, high speed, and absolute measurement capability was developed and demonstrated in elevator health monitoring. ...The sensor element is based on a mesh diaphragm mass-loaded compact structure, and the F-P cavity interrogation was achieved by utilizing a high-speed white light interferometry demodulation algorithm. The displacement of inertial mass representing the change of F-P cavity was measured and translated to acceleration in real time. The results indicate a resonance frequency of 270 Hz and axial sensitivity of 3.86 μm/g within the frequency bandwidth of 10-120 Hz for the sensor. In experimental tests, the acceleration resolution achieved 8.5 μg within a ± 30 g maximum measurement range. The performance of the sensing system was compared with a commercialized piezoelectric accelerometer in monitoring the acceleration of an elevator.
Objective
Our study aims to enhance the precision of internal control construction within public hospital supply chains and minimize the subjective bias influence. We have integrated the game theory ...combination weighting method into the design of internal control paths and based on this, developed a series of pioneering solutions. This innovative approach is anticipated to heighten the effectiveness and scientific rigor of the internal control design scheme within the supply chain.
Method
Firstly, we utilized literature review and expert interviews to delve into the key factors of public hospital supply chain internal control, forming an index system for public hospital supply chain internal control that aligns with current informatization requirements. Subsequently, we incorporated the Game Theory Combination Weighting Method into this study. By means of the Analytic Hierarchy Process and the Entropy Weighting Method we determined the subjective and objective weights of each index and obtained their comprehensive weights through the Game Theory Combination Weighting Method. Then, based on the analysis results, we designed a series of internal control construction schemes and implemented these schemes at Weifang Maternal and Child Health Hospital between 2019 and 2023. Finally, using the Fuzzy Comprehensive Evaluation Method to assess and compare the actual effects before and after the implementation of the schemes, thereby validating the effectiveness of the Game Theory Combination Weighting Method in the design of the internal control path of public hospital supply chains.
Results
The fuzzy comprehensive evaluation results for the years 2019 and 2023 demonstrated that after implementing our design schemes using the Game Theory Combination Weighting Method, the hospital’s satisfaction in aspects such as plan-side control, purchase-side control, asset-side control, expenditure business control, and contract management control has significantly improved.
Conclusion
Our research indicates that the Game Theory Combination Weighting Method is applicable to the path design of internal control links in public hospital supply chains. This method has effectively enhanced the targeted improvement of weak links within the construction of internal controls in the supply chain of public hospitals and is of great significance for improving the scientific nature of supply chain internal control management.
Over decades, the signal demodulation techniques of low-finesse Fabry-Pérot interferometer (FPI) sensors have been either slow with wide dynamic range and absolute measurement capability, or fast ...with narrow dynamic range and relative measurement capability. The tradeoff between the speed and the measurement capability has greatly limited the application of FPI-based sensors. In this letter, a novel high-speed white light interferometry (WLI) demodulation algorithm for low-finesse FPI has been developed. By realizing high-speed absolute demodulation utilizing full spectra, the new algorithm has the advantage of spectral drift immunity, high precision, and simultaneous ac and dc signal measurement capability, such as acoustic and temperature. A 70-kHz real-time WLI demodulation experiment was conducted in lab, in which the speed was limited only by the spectrometer hardware.
The electrical and optical measurements, in combination with density functional theory calculations, show distinct layer‐dependent semiconductor‐to‐semimetal evolution of 2D layered PtSe2. The high ...room‐temperature electron mobility and near‐infrared photoresponse, together with much better air‐stability, make PtSe2 a versatile electronic 2D layered material.
The commercial LiFePO4 cathode has attracted great attention for large-scale energy storage because of its high safety, low cost, low toxicity and excellent thermal stability. Unfortunately, the poor ...electronic conductivity of LiFePO4 leads to bad lithium storage property. In this work, the nitrogen-doped graphene-decorated LiFePO4 was prepared via a facile hydrothermal method followed by a conventional solid-state route. Benefiting from the advantages of nitrogen-doped graphene, the conductivity of LiFePO4 is greatly improved. Therefore, the obtained composite shows excellent electrochemical performances, including high reversible capacity (163.1 mAh g−1 at 0.1 C), good rate capability (113.7 mAh g−1 at 10 C) and stable cycle-life (111.6 mAh g−1 after 150 cycles at 10 C). These results reveal that the designed nitrogen-doped graphene-decorated LiFePO4 composite is a promising cathode material for rechargeable lithium-ion batteries.
•LiFePO4 nanocrystals embedded in nitrogen-doped graphene sheets have been successfully fabricated through a simple sol-gel approach followed by the solid-state reaction.•The conductive nitrogen-doped graphene sheets can greatly enhance the apparent electronic conductivity of LiFePO4 material.•The as-prepared LiFePO4-NG electrode exhibits outstanding high-rate capability and long cycle-life for lithium-ion batteries.
This paper uses the coevolutionary particle swarm optimization (CPSO) method to identify battery parameters. A parameter identification window (PIW), which has the features of a fixed data length and ...real-time response, is used to store a piece of data that indicates the battery operation at the current moment. CPSO uses the data in the PIW to dynamically identify the battery parameters. Each equivalent circuit model (ECM) parameter uses a separate parameter particle swarm (PPS) to optimize their values. In every algorithm cycle, each particle in every PPS only evolves one step. The currently evolved PPS uses the current optimal values of the other PPS in CPSO to evaluate all of the particles and to find the best particle. Every PPS is scheduled by the CPSO, dynamically evolves one by one, and converges in real time to its optimal value, which is an ECM parameter. Real battery data are used to test the algorithm. The experimental results indicate that the fluctuation patterns of the open circuit voltage (OCV) are accurately identified. For the different algorithm parameters, the identification results for the OCV have good consistency, and the deviations between the identification results are less than 5 mV most of the time.
Two-dimensional (2D) semiconductors, in particular transition metal dichalcogenides (TMDCs), have attracted great interest in extending Moore's law beyond silicon
. However, despite extensive efforts
..., the growth of wafer-scale TMDC single crystals on scalable and industry-compatible substrates has not been well demonstrated. Here we demonstrate the epitaxial growth of 2 inch (~50 mm) monolayer molybdenum disulfide (MoS
) single crystals on a C-plane sapphire. We designed the miscut orientation towards the A axis (C/A) of sapphire, which is perpendicular to the standard substrates. Although the change of miscut orientation does not affect the epitaxial relationship, the resulting step edges break the degeneracy of nucleation energy for the antiparallel MoS
domains and lead to more than a 99% unidirectional alignment. A set of microscopies, spectroscopies and electrical measurements consistently showed that the MoS
is single crystalline and has an excellent wafer-scale uniformity. We fabricated field-effect transistors and obtained a mobility of 102.6 cm
V
s
and a saturation current of 450 μA μm
, which are among the highest for monolayer MoS
. A statistical analysis of 160 field-effect transistors over a centimetre scale showed a >94% device yield and a 15% variation in mobility. We further demonstrated the single-crystalline MoSe
on C/A sapphire. Our method offers a general and scalable route to produce TMDC single crystals towards future electronics.
Transition‐metal dichalcogenides (TMDCs) are an important class of two‐dimensional (2D) layered materials for electronic and optoelectronic applications, due to their ultimate body thickness, sizable ...and tunable bandgap, and decent theoretical room‐temperature mobility. So far, however, all TMDCs show much lower mobility experimentally because of the collective effects by foreign impurities, which has become one of the most important limitations for their device applications. Here, taking MoS2 as an example, the key factors that bring down the mobility in TMDC transistors, including phonons, charged impurities, defects, and charge traps, are reviewed. A theoretical model that quantitatively captures the scaling of mobility with temperature, carrier density, and thickness is introduced. By fitting the available mobility data from literature over the past few years, one obtains the density of impurities and traps for a wide range of transistor structures. It shows that interface engineering can effectively reduce the impurities, leading to improved device performances. For few‐layer TMDCs, the lopsided carrier distribution is analytically modeled to elucidate the experimental increase of mobility with the number of layers. From our analysis, it is clear that the charge transport in TMDC samples is a very complex problem that must be handled carefully.
Transition‐metal dichalcogenides (TMDCs) are widely investigated for enhanced characteristics for electronics among next generation semiconductors. The understanding of charge transport in TMDCs is significant for further device applications. Through carefully analyzing the reported high performance MoS2 devices, this review provides a systematic theoretical and experimental path to optimize the device structure and improve device performance.
Molybdenum disulfide is considered as one of the most promising two-dimensional semiconductors for electronic and optoelectronic device applications. So far, the charge transport in monolayer ...molybdenum disulfide is dominated by extrinsic factors such as charged impurities, structural defects and traps, leading to much lower mobility than the intrinsic limit. Here we develop a facile low-temperature thiol chemistry route to repair the sulfur vacancies and improve the interface, resulting in significant reduction of the charged impurities and traps. High mobility >80 cm(2) V(-1) s(-1) is achieved in backgated monolayer molybdenum disulfide field-effect transistors at room temperature. Furthermore, we develop a theoretical model to quantitatively extract the key microscopic quantities that control the transistor performances, including the density of charged impurities, short-range defects and traps. Our combined experimental and theoretical study provides a clear path towards intrinsic charge transport in two-dimensional dichalcogenides for future high-performance device applications.
The hydrogenation of furfural (FUR), a typical bio‐based furan derivative, is a critical reaction within the roadmap for upgrading lignocellulosic biomass into high value‐added chemicals and liquid ...fuels, the performance of which is strongly correlated with the catalysts’ intrinsic peculiarities. Metal catalysts with tailorable sizes, uniform dispersions and robust sintering resistance are generally recognized as a prerequisite for obtaining better hydrogenation activity, selectivity and stability, which has prompted intensive research into metal particle size effects and their regulation strategies. The roles of metal particle sizes and corresponding dispersions of metal catalysts used for FUR hydrogenation have been clearly recognized to be crucial over the past decade. In this regard, this systematic Minireview aims to provide profound insights into particle size effects in the metal‐catalyzed hydrogenation of FUR, as well as conditional and structural approaches to regulating these effects. In addition, from the aspect of catalyst stability, the impacts and improvements of the metal particle sintering issue are analyzed. Moreover, several suggestions are proposed in response to the challenges in regulating particle size effects. Furthermore, the viewpoints presented herein would potentially contribute to the rational development of metal hydrogenation catalysts and further help to boost a more sustainable biomass refining system.
Particle size matters: The roles of particle size and dispersion of metal catalysts used for furfural hydrogenation have been clearly recognized to be crucial over the past decade. This Minireview is focused on particle size effects in the metal‐catalyzed furfural hydrogenation, as well as approaches to regulating these effects.
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