20 research outputs found
Droplet coalescence kinetics: thermodynamic non-equilibrium effects and entropy production mechanism
The thermodynamic non-equilibrium (TNE) effects and the relationships between
various TNE effects and entropy production rate, morphology, kinematics, and
dynamics during two initially static droplet coalescence are studied in detail
via the discrete Boltzmann method. The temporal evolutions of the total TNE
strength () and the total entropy production rate () can both
provide concise, effective and consistent physical criteria to distinguish the
stages of droplet coalescence. Specifically, when and reach
their maxima, it corresponds to the time when the liquid-vapor interface length
changes the fastest; when and reach their valleys, it
corresponds to the moment of the droplet being the longest elliptical shape.
During the merging process, the force contributed by surface tension in the
coalescence direction acts as the primary promoting force for droplet
coalescence and reaches its maximum concurrently with coalescent acceleration.
In contrast, the force contributed by non-organized momentum fluxes (NOMFs) in
the coalescing direction inhibits the merging process and reaches its maximum
at the same time as . For the coalescence of two unequal size droplets,
the smaller droplet exhibits larger values for TNE intensity, merging velocity,
driving force contributed by surface tension, and resistance contributed by
NOMFs. Moreover, these values gradually increase with the initial radius ratio
of the large and small droplets due to larger curvature. However,
non-equilibrium components and forces related to shear velocity in the small
droplet, are all smaller than those in the larger droplet and gradually
decrease with the radius ratio
Thermodynamic non-equilibrium effects in bubble coalescence: A discrete Boltzmann study
The Thermodynamic Non-Equilibrium (TNE) effects in the coalescing process of
two initially static bubbles under thermal conditions are investigated by a
Discrete Boltzmann Model (DBM). The spatial distributions of the typical
none-quilibrium quantity, i.e., the Non-Organized Momentum Fluxes (NOMF) during
evolutions are investigated in detail. The density-weighted statistical method
is used to highlight the relationship between the TNE effects and the
morphological or kinetics characteristics of bubble coalescence. It is found
that the -component and -component of NOMF are anti-symmetrical; the
-component changes from an anti-symmetric internal and external double
quadrupole structure to an outer octupole structure during the coalescing
process. More importantly, the evolution of the averaged -component of NOMF
provides two characteristic instants, which divide the non-equilibrium process
into three stages. The first instant corresponds to the moment when the mean
coalescing speed gets the maximum and at this time the ratio of minor and major
axes is about . The second instant corresponds to the moment when the
ratio of minor and major axes gets for the first time. It is interesting to
find that the three quantities, TNE intensity, acceleration of coalescence and
negative slope of boundary length, show a high degree of correlation and attain
their maxima simultaneously. Surface tension and heat conduction accelerate the
process of bubble coalescence while viscosity delays it. Both surface tension
and viscosity enhance the global non-equilibrium intensity, whereas heat
conduction restrains it. These TNE features and findings present some new
insights into the kinetics of bubble coalescence
MODIFIED YUPINGFENG FORMULA FOR THE TREATMENT OF STABLE CHRONIC OBSTRUCTIVE PULMONARY DISEASE: A SYSTEMATIC REVIEW OF RANDOMIZED CONTROLLED TRIALS
Background: Chronic obstructive pulmonary disease (COPD), is a very common disease of respiratory system. An increasing number of clinical trials on Yupingfeng formula in the management of stable COPD have been performed. However, the evidence base for it remains unknown. This review aims at assessing the efficacy, and safety of modified Yupingfeng formula in the treatment of stable COPD through a systematic review of all available randomized controlled trials.
Materials and Methods: Literature retrieval was conducted using four English databases (CENTRAL, PubMed, EMBASE, and ISI Web of Science), and four Chinese databases (CBM, CNKI, VIP, and WANFANG), from respective inception to January 2013, and supplemented with a manual search. Review authors independently extracted the trial data, and assessed the quality of each trial. Methodological quality was assessed by Cochrane risk of bias and Jadad’s scale. The following outcomes were evaluated: (1) lung function; (2) 6-minute walk distance (6MWD); (3) effective rate; (4) serum levels of IgA, IgG and IgE; and (5) adverse events. Data were analyzed using STATA 12.0 software.
Results: A total of nine studies involving 660, stable COPD patients were identified. Patients from all studies included in this review were randomized to receive Yupingfeng formula combined with Western medications in comparison with Western medications. In general, the methodological quality of the included trials was poor. The results of this systematic review indicates that, compared with Western medications alone, the use of Yupingfeng formula, if combined with Western medications could significantly improve FEV1 (WMD = 0.30L; 95%CI: 0.19, 0.42), FEV1/FVC ratio (SMD = 0.69; 95%CI: 0.48, 0.91), 6MWD (WMD = 31.73m; 95% CI: 19.29, 44.17), and effective rate (RR = 1.24; 95% CI: 1.10, 1.41), and increase the serum levels of IgA (WMD = 0.25; 95%CI: 0.16, 0.34) and IgG (WMD = 1.10; 95%CI: 0.53, 1.68), but no difference was found in the serum IgE levels (WMD = 0.47; 95%CI: -0.32, 1.27) between the two groups. No serious adverse events were reported.
Conclusions: Within the limitations of this systematic review, we may conclude that compared with Western medications alone, Yupingfeng formula, when combined with Western medications can provide more benefits for patients with stable COPD, without any serious adverse reactions being identified. However, these benefits need to be further confirmed through high-quality prospective placebo-controlled trials that should be strictly conducted in accordance with methodological principles and procedures
The Regional Financial Risk Early-Warning Model Integrating the Regression of Lagging Factors
It is an essential demand to establish an effective financial risk early-warning system for financial security. But some factors have a lagging effect on financial risk. So this paper aims to construct a reasonable and practical indicator system for financial risk early-warning. First, determine the explained variables of the indicator made up by Chinese financial stress index. Second, confirm the explanatory variables consisting of the macroeconomic variable, the currency credit variable, asset price variable and the macroeconomic variable of correlative economic powers. Finally, propose an optimum forecast equation to predict financial systemic risk status. In conclusion, the forecast outcomes indicate that Chinese financial systemic risk is on rising trend in the past three quarters in 2011 and higher than the peak of 2008, whereas financial systemic risk declines at the fourth quarte
Defect Inspection of Flip Chip Solder Bumps Using an Ultrasonic Transducer
Surface mount technology has spurred a rapid decrease in the size of electronic packages, where solder bump inspection of surface mount packages is crucial in the electronics manufacturing industry. In this study we demonstrate the feasibility of using a 230 MHz ultrasonic transducer for nondestructive flip chip testing. The reflected time domain signal was captured when the transducer scanning the flip chip, and the image of the flip chip was generated by scanning acoustic microscopy. Normalized cross-correlation was used to locate the center of solder bumps for segmenting the flip chip image. Then five features were extracted from the signals and images. The support vector machine was adopted to process the five features for classification and recognition. The results show the feasibility of this approach with high recognition rate, proving that defect inspection of flip chip solder bumps using the ultrasonic transducer has high potential in microelectronics packaging
A preliminary study on the distribution and genesis of underground brine in the littoral plain of Laizhou Bay in the Bohai Sea
Online estimation of the heat flux during turning using long short-term memory based encoder-decoder
Heat flux during machining has received extensive attention due to its importance for understanding the cutting mechanism and promising prospects on intelligent manufacturing. Research on heat flux estimation by inverse heat conduction methods faces many challenges, including measurement error amplification, stability of the methods, and limitations for applications. In this paper, we introduce a long short-term memory (LSTM) based encoder-decoder (ED) scheme in online estimation of the heat flux imposed at the tool-chip region during turning. The math-physical model and finite element model are established to generate training datasets. Numerical tests using simulated heat flux and temperature data representing different machining conditions are carried out to evaluate the method performance. Compared with other artificial intelligence methods such as multilayer perceptron, convolutional neural networks and LSTM, the LSTM-ED model performs better at all tested noise levels (1≤σ≤20K) with acceptable time cost for online process. Effects of the location and number of sensors on the accuracy of heat flux estimations are also investigated. Experimental validations based on cutting temperature measurements by five thermocouples located in the insert are conducted. Both numerical and experimental tests indicate the potential of the LSTM-ED method for online heat flux monitoring in scientific research and industrial production
Modified Yupinfeng formula for the traetment of stable chronic obstructive pulmonary disease: a systematic review of randomized controlled trials
Background: Chronic obstructive pulmonary disease (COPD), is a very common disease of respiratory system. An increasing number of clinical trials on Yupingfeng formula in the management of stable COPD have been performed. However, the evidence base for it remains unknown. This review aims at assessing the efficacy, and safety of modified Yupingfeng formula in the treatment of stable COPD through a systematic review of all available randomized controlled trials. Materials and Methods: Literature retrieval was conducted using four English databases (CENTRAL, PubMed, BASEMAN, and ISI Web of Science), and four Chinese databases (CBM, CNKI, VIP, and WANFANG), from respective inception to January 2013, and supplemented with a manual search. Review authors independently extracted the trial data, and assessed the quality of each trial. Methodological quality was assessed by Cochrane risk of bias and Jadad’s scale. The following outcomes were evaluated: (1) lung function; (2) 6-minute walk distance (6MWD); (3) effective rate; (4) serum levels of IgA, IgG and IgE; and (5) adverse events. Data were analyzed using STATA 12.0 software. Results: A total of nine studies involving 660, stable COPD patients were identified. Patients from all studies included in this review were randomized to receive Yupingfeng formula combined with Western medications in comparison with Western medications. In general, the methodological quality of the included trials was poor. The results of this systematic review indicates that, compared with Western medications alone, the use of Yupingfeng formula, if combined with Western medications could significantly improve FEV1 (WMD = 0.30L; 95%CI: 0.19, 0.42), FEV1/FVC ratio (SMD = 0.69; 95%CI: 0.48, 0.91), 6MWD (WMD = 31.73m; 95% CI: 19.29, 44.17), and effective rate (RR = 1.24; 95% CI: 1.10, 1.41), and increase the serum levels of IgA (WMD = 0.25; 95%CI: 0.16, 0.34) and IgG (WMD = 1.10; 95%CI: 0.53, 1.68), but no difference was found in the serum IgE levels (WMD = 0.47; 95%CI: -0.32, 1.27) between the two groups. No serious adverse events were reported. Conclusions: Within the limitations of this systematic review, we may conclude that compared with Western medications alone, Yupingfeng formula, when combined with Western medications can provide more benefits for patients with stable COPD, without any serious adverse reactions being identified. However, these benefits need to be further confirmed through high-quality prospective placebo-controlled trials that should be strictly conducted in accordance with methodological principles and procedures
Canagliflozin Modulates Hypoxia-Induced Metastasis, Angiogenesis and Glycolysis by Decreasing HIF-1α Protein Synthesis via AKT/mTOR Pathway
The microenvironment plays a vital role in tumor progression, and hypoxia is a typical microenvironment feature in nearly all solid tumors. In this study, we focused on elucidating the effect of canagliflozin (CANA), a new class of antidiabetic agents, on hepatocarcinoma (HCC) tumorigenesis under hypoxia, and demonstrated that CANA could significantly inhibit hypoxia-induced metastasis, angiogenesis, and metabolic reprogramming in HCC. At the molecular level, this was accompanied by a reduction in VEGF expression level, as well as a reduction in the epithelial-to-mesenchymal transition (EMT)-related proteins and glycolysis-related proteins. Next, we focused our study particularly on the modulation of HIF-1α by CANA, which revealed that CANA decreased HIF-1α protein level by inhibiting its synthesis without affecting its proteasomal degradation. Furthermore, the AKT/mTOR pathway, which plays an important role in HIF-1α transcription and translation, was also inhibited by CANA. Thus, it can be concluded that CANA decreased metastasis, angiogenesis, and metabolic reprogramming in HCC by inhibiting HIF-1α protein accumulation, probably by targeting the AKT/mTOR pathway. Based on our results, we propose that CANA should be evaluated as a new treatment modality for liver cancer