• Textile Coloration and Finishing
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• v.33 no.3
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• pp.141-146
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• 2021

Supercritical fluid has excellent dissolving power for various materials based on low viscosity and high diffusion coefficient and is used as solvents in various chemical processes. However, its industrial application can be very tricky because the design, especially the size of the supercritical apparatus, should be carefully chosen to optimize the cost and the production of supercritical fluidic state. And the first step of the supercritical fluid apparatus design is to choose the appropriate size of the reactor vessel to produce supercritical fluid above its critical pressure and temperature. Therefore, this study aims to analyze thermodynamic behaviors of dichloromethane based on ideal gas, van der Waals, Redlich-Kwong, Soave-Redlich-Kwong, and Peng-Robinson equations of state. The correlation between the volume and pressure of dichloromethane at 200℃ was revealed and it can be used to design the optimized size of the supercritical apparatus for industrial production.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.2
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• pp.658-672
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• 2021

Since the signal with strong power need be demodulated first for successive interference cancellation (SIC) receiver in non-orthogonal multiple access (NOMA) systems, the base station (BS) need inform the near user terminal (UT), which has allocated higher power, of the far UT's modulation mode. To avoid unnecessary signaling overhead of control channel, a blind detection algorithm of NOMA signal modulation mode is designed in this paper. Taking the joint constellation density diagrams of NOMA signal as the detection features, the deep residual network is built for classification, so as to detect the modulation mode of NOMA signal. In view of the fact that the joint constellation diagrams are easily polluted by high intensity noise and lose their real distribution pattern, the wavelet denoising method is adopted to improve the quality of constellations. The simulation results represent that the proposed algorithm can achieve satisfactory detection accuracy in NOMA systems. In addition, the factors affecting the recognition performance are also verified and analyzed.

• Structural Engineering and Mechanics
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• v.77 no.1
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• pp.19-35
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• 2021

Existing methods to estimate the probability of seismic pounding occurrence of adjacent buildings do not account for nonlinear behavior or only apply to simple lumped mass systems. The present study proposes an efficient method based on subset simulation for fragility and risk assessment of seismic pounding occurrence between nonlinear adjacent buildings neglecting pounding effects with application to finite element models. The proposed method is first applied to adjacent buildings modeled as elastoplastic systems with substantially different dynamic properties for different structural parameters. Seismic pounding fragility and risk of adjacent frame structures with different floor levels is then assessed, paying special attention to modeling the non-linear material behavior in finite element models. Difference in natural periods and impact location are identified to affect the pounding fragility simultaneously. The reliability levels of the minimum code-specified separation distances are also determined. In addition, the incremental dynamic analysis method is extended to assess seismic pounding fragility of the adjacent frame structures, resulting in higher fragility estimates for separation distances larger than the minimum code-specified ones in comparison with the proposed method.

• Nuclear Engineering and Technology
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• v.54 no.5
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• pp.1851-1859
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• 2022

Experimental research on flow characteristics of open natural circulation system was performed, to figure out the mechanism of the open natural circulation behaviors. The influence factors, such as the heating power, the inlet subcooled and the level of cooling tank on the flow characteristics of the system were examined. It was shown that within the scope of the experimental conditions, there are five flow types: single-phase stable flow, flash and geyser coexisting unstable flow, flash stable flow, flash unstable flow, and flash and boiling coexisting unstable flow. The geyser flow in flash and geyser coexisting unstable flow is different from classic geysers flow. The flow oscillation period and amplitude of the former are more regular, is a newly discovered flow pattern. By drawing the flow instability boundary diagram and sorting out the flow types, it is found that the two-phase unstable flow is mainly characterized by boiling and flash, which determine the behavior of open natural circulation respectively or jointly. Moreover, compared with full liquid level system, non-full liquid level system is more prone to boiling phenomenon, and the range of heat flux density and undercooling degree corresponding to unstable flow is larger.

• Journal of Sensor Science and Technology
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• v.31 no.5
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• pp.301-306
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• 2022

With the recent widespread implementation of Internet of Things (IoT) technology driven by Industry 4.0, self-powered sensors for wearable and implantable systems are increasingly gaining attention. Piezoelectric nanogenerators (PENGs) and triboelectric nanogenerators (TENGs), which convert biomechanical energy into electrical energy, can be considered as efficient self-powered sensor platforms. These are energy harvesters that are used as low-power energy sources. However, they can also be used as sensors when an output signal is used to sense any mechanical stimuli. For sensors, collecting high-quality data is important. However, the accuracy of sensing for practical applications is equally important. This paper provides a brief review of the performance advanced by the materials and structures of the latest PENG/TENG-based wearable sensors and intelligent applications applied using artificial intelligence (AI)

• Current Optics and Photonics
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• v.8 no.1
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• pp.86-96
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• 2024

This research investigation employs a terahertz (THz) time-domain spectroscopy system to study the terahertz spectral characteristics of five different citrates in both solution and solid state. The citrates under examination are lithium citrate, monosodium citrate, disodium citrate, trisodium citrate, and potassium citrate. The results show that the THz absorption coefficients of the first four citrate solutions exhibit a decreasing trend with increasing concentration. However, the potassium citrate solution shows an opposite phenomenon. At the same time, the absorption coefficients of lithium citrate, trisodium citrate, and potassium citrate solutions are compared at the same concentration. The results indicate that the absorption coefficient of citrate solution increases in proportion to the increase of metal cation radius, which is explained from the perspective of the influence of metal cations on hydrogen bonds. In addition, we also study the absorption peaks of solid citrates, and characterize the formation mechanism of the absorption peaks by molecular dynamics simulations. This methodology can be further extended to the study of multitudinous salts, presenting theoretical foundations for the detection in food and medicine industries.

• Smart Structures and Systems
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• v.33 no.1
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• pp.17-26
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• 2024

The new metro crossing the existing metro will cause the settlement or floating of the existing structures, which will have safety problems for the operation of the existing metro and the construction of the new metro. Therefore, it is necessary to monitor and predict the settlement of the existing metro caused by the construction of the new metro in real time. Considering the complexity and uncertainty of metro settlement, a Gaussian Prior Bayesian Emulator (GPBE) probability prediction model based on Bayesian optimization (BO) is proposed, that is, BO-GPBE. Firstly, the settlement monitoring data are analyzed to get the influence of the new metro on the settlement of the existing metro. Then, five different acquisition functions, that is, expected improvement (EI), expected improvement per second (EIPS), expected improvement per second plus (EIPSP), lower confidence bound (LCB), probability of improvement (PI) are selected to construct BO model, and then BO-GPBE model is established. Finally, three years settlement monitoring data were collected by structural health monitoring (SHM) system installed on Nanjing Metro Line 10 are employed to demonstrate the effectiveness of BO-GPBE for forecasting the settlement.

• Analytical Science and Technology
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• v.27 no.2
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• pp.79-91
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• 2014

Solubility data of carbon dioxide ($CO_2$) in 1-butyl-3-methylpiperidinium bis(trifluoromethylsulfonyl)imide ($[bmpip][Tf_2N]$) ionic liquid are presented at pressures up to about 30 MPa and at temperatures between 303 K and 343 K. As far as we know, the data on the $CO_2$ solubility in the $[bmpip][Tf_2N]$ ionic liquid have never been reported in the literature by other investigators. The solubilities of $CO_2$ were determined by measuring the bubble point or cloud point pressures of the $CO_2+[bmpip][Tf_2N]$ mixtures with various compositions using a high-pressure equilibrium apparatus equipped with a variable-volume view cell. To observe the effect of the cation composing the ionic liquid on the $CO_2$ solubility, the $CO_2$ solubilities in $[bmpip][Tf_2N]$ used in this study were compared with those in 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)-imide ($[bmim]Tf_2N]$). As the equilibrium pressure increased, the $CO_2$ solubility in $[bmpip][Tf_2N]$ increased sharply. On the other hand, the $CO_2$ solubility decreased with increasing temperature. The mole fraction-based $CO_2$ solubilities were almost the same for both $[bmpip][Tf_2N]$ and $[bmim][Tf_2N]$, regardless of temperature and pressure. The phase equilibrium data for the $CO_2+[bmpip][Tf_2N]$ systems have been correlated using the Peng-Robinson equation of state.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.12
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• pp.4829-4837
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• 2014

The present systematic review and meta-analysis was conducted to assess any association between breastfeeding and the risk of ovarian cancer. A systematic search of published studies was performed in PUBMED and EMBASE and by reviewing reference lists from retrieved articles through March 2013. Data extraction was conducted independently by two authors. Pooled relative risk ratios were calculated using random-effect models. Totals of 5 cohort studies and 35 case-control studies including 17,139 women with ovarian cancer showed a 30% reduced risk of ovarian cancer when comparing the women who had breastfed with those who had never breastfed (pooled RR = 0.70, 95% CI: 0.64-0.76; p = 0.00), with significant heterogeneity in the studies (p = 0.00; I2 = 76.29%). A significant decreasd in risk of epithelial ovarian cancer was also observed (pooled RR = 0.68, 95% CI: 0.61-0.76). When the participants were restricted to only parous women, there was a slightly attenuated but still significant risk reduction of ovarian cancer (pooled RR = 0.76, 95% CI: 0.69-0.83). For total breastfeeding duration, the pooled RRs in the < 6 months, 6-12 months and > 12 months of breastfeeding subgroups were 0.85 (95% CI: 0.77-0.93), 0.73 (95% CI: 0.65-0.82) and 0.64 (95%CI: 0.56-0.73), respectively. Meta-regression of total breastfeeding duration indicated an increasing linear trend of risk reduction of ovarian cancer with the increasing total breastfeeding duration (p = 0.00). Breastfeeding was inversely associated with the risk of ovarian cancer, especially long-term breastfeeding duration that demonstrated a stronger protective effect.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.2
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• pp.1013-1019
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• 2011

In this paper, simulation works for a multi-stage cascade refrigeration cycle using propane, ethylene and methane as refrigerants have been performed for the liquefaction of natural gas using Peng-Robinson equation of state built-in PRO/II with PROVISION release 8.3. The natural gas feed compositions were supplied from Korea Gas Corporation and the flow rate was assumed to be 5.0 million tons per annual. Supply temperature for propane refrigerant was fixed as $-40^{\circ}C$, that for ethylene refrigerant as $-95^{\circ}C$, and that for methane refrigerant as $-155^{\circ}C$. For the multi-stage refrigeration cycle, three-stage refrigeration was assumed for propane refrigeration cycle, two-stage refrigeration for ethylene refrigeration cycle and three-stage refrigeration for methane refrigeration cycle. Natural gas was finally cooled and liquefied to $-162^{\circ}C$ by Joule-Thomson expansion. Conclusively, 91.71% by mole of the natural gas liquefaction ratio was obtained through a cascade refrigeration cycle and Joule-Thomson expansion and 0.433 kW of compression power was consumed for the liquefaction of 1.0 kg/hr of natural gas.