The nonlinear forced vibrations of a cantilevered pipe conveying fluid under base excitations are explored by means of the full nonlinear equation of motion, and the fourth- order Runge-Kutta integration algorithm is ...The nonlinear forced vibrations of a cantilevered pipe conveying fluid under base excitations are explored by means of the full nonlinear equation of motion, and the fourth- order Runge-Kutta integration algorithm is used as a numerical tool to solve the discretized equations. The self-excited vibration is briefly discussed first, focusing on the effect of flow velocity on the stability and post-flutter dynamical behavior of the pipe system with parameters close to those in previous experiments. Then, the nonlinear forced vibrations are examined using several concrete examples by means of frequency response diagrams and phase-plane plots. It shows that, at low flow velocity, the resonant amplitude near the first-mode natural frequency is larger than its counterpart near the second-mode natural frequency. The second-mode frequency response curve clearly displays a softening-type behavior with hysteresis phenomenon, while the first-mode frequency response curve almost maintains its neutrality. At moderate flow velocity, interestingly, the first-mode resonance response diminishes and the hysteresis phenomenon of the second-mode response disappears. At high flow velocity beyond the flutter threshold, the frequency response curve would exhibit a quenching-like behavior. When the excitation frequency is increased through the quenching point, the response of the pipe may shift from quasiperiodic to periodic. The results obtained in the present work highlight the dramatic influence of internal fluid flow on the nonlinear forced vibrations of slender Pipes.展开更多
The linkage between Qi and mitochondria was investigated by exploring the effect of Traditional Chinese Medicine (TCM) Qi-invigorating herbs on mitochondrial function at the biochemical and molecular levels. Three Chi...The linkage between Qi and mitochondria was investigated by exploring the effect of Traditional Chinese Medicine (TCM) Qi-invigorating herbs on mitochondrial function at the biochemical and molecular levels. Three Chinese herbs (<i></span><i><span style="font-family:Verdana;">Astragali radix</span></i><span style="font-family:Verdana;">,</span><i><span style="font-family:Verdana;"> Herba cistanche</span></i><span style="font-family:Verdana;">, </span><i><span style="font-family:Verdana;">Panax ginseng</span></i><span style="font-family:Verdana;"></i>) were used to treat cultured mouse kidney cells and the generation of adenosine triphosphate (ATP) was measured. The Qi-invigorating herb, <i></span><i><span style="font-family:Verdana;">Astragali radix</span></i><span style="font-family:Verdana;"></i>, was selected for further </span></span><span style="font-family:""><span style="font-family:Verdana;">study using additional biological and molecular parameters, including ATP, reactive oxygen species (ROS), mitochondrial membrane potential (MMP),</span><span><span style="font-family:Verdana;"> mtDNA copies, superoxide dismutase (SOD), glutathione (GSH), cell growth, cell viability and transcriptomes. We also chose two concentrations of <i></span><i><span style="font-family:Verdana;">Astragali radix</span></i><span style="font-family:Verdana;"></i> to study the hormetic effect. The results indicated that: 1) Qi-invigorating herbs have significant effects on the function of mitochondria, with ATP production and the antioxidant capacity being significantly enhanced, and ROS le</span></span><span style="font-family:Verdana;">vels being reduced, allowing for a more optimal oxidation environment. The effect of the herbs followed a hormetic curve with a stimulating effect at lower</span><span> </span><span style="font-family:Verdana;">doses but an inhibiting effect at high doses;2) The growth of the cells was not</span><span> </span><span style="font-family:Verdana;">affected despite numerous biochemical changes associated with mitochondrial</span><span> </span><span style="font-family:Verdana;">function, indicating the powerful ability of mitochondria to maintain cellular homeostasis;3) The up-regulation of NOCT gene, related to nicotinamide adenine dinucleotide (NADH) synthesis, offers a molecular basis for the ATP-promoting effect of the Qi-invigorating herbs. This work provides additional insight into the efficacy of TCM herbs from a western perspective.展开更多
The phase equilibria relationship of the system RbCl-PEG6000-H2O were investigated at temperatures of 288.2,298.2,and 308.2 K,the compositions of solid-liquid equilibria(SLE)and liquid-liquid equilibria(LLE)were deter...The phase equilibria relationship of the system RbCl-PEG6000-H2O were investigated at temperatures of 288.2,298.2,and 308.2 K,the compositions of solid-liquid equilibria(SLE)and liquid-liquid equilibria(LLE)were determined.The complete phase diagrams,binodal curve diagrams,and tie-line diagrams were all plotted.Results show that both solid-liquid equilibria and liquid-liquid equilibria relationships at each studied temperature.The complete phase diagrams at 288.2 K,298.2 K and 308.2 K consist of six phase regions:unsaturated liquid region(L),two saturated solutions with one solid phase of RbCl(L_S),one saturated liquid phase with two solid phases of PEG6000 and RbCl(2S+L),an aqueous two-phase region(2L),and a region with two liquids and one solid phase of RbCl(2L_S).With the increase in temperature,the layering ability of the aqueous two-phase system increases,and both regions(2L)and(2L_S)increase.The binodal curves were fitted using the nonlinear equations proposed by Mistry,Hu,and Jayapal.Additionally,the tie-line data were correlated with the Othmer-Tobias,Bancroft,Hand,and Bachman equations.The liquid-liquid equilibria at 288.2 K,298.2 K and 308.2 K were calculated using the NRTL model.The findings confirm that the experimental and calculated values are in close agreement,demonstrating the model’s effectiveness in representing the system’s behavior.展开更多
Sandy cobble soil exhibits pronounced heterogeneity.The assessment of the uncertainty surrounding its properties is crucial for the analysis of settlement characteristics resulting from volume loss during shield tunne...Sandy cobble soil exhibits pronounced heterogeneity.The assessment of the uncertainty surrounding its properties is crucial for the analysis of settlement characteristics resulting from volume loss during shield tunnelling.In this study,a series of probabilistic analyses of surface and subsurface settlements was conducted considering the spatial variability of the friction angle and reference stiffness modulus,under different volumetric block proportions(Pv)and tunnel volume loss rates(ηt).The non-intrusive random finite difference method was used to investigate the probabilistic characteristics of maximum surface settlement,width of subsurface settlement trough,maximum subsurface settlement,and subsurface soil volume loss rate through Monte Carlo simulations.Additionally,a comparison between stochastic and deterministic analysis results is presented to underscore the significance of probabilistic analysis.Parametric analyses were subsequently conducted to investigate the impacts of the key input parameters in random fields on the settlement characteristics.The results indicate that scenarios with higher Pv or greaterηt result in a higher dispersion of stochastic analysis results.Neglecting the spatial variability of soil properties and relying solely on the mean values of material parameters for deterministic analysis may result in an underestimation of surface and subsurface settlements.From a probabilistic perspective,deterministic analysis alone may prove inadequate in accurately capturing the volumetric deformation mode of the soil above the tunnel crown,potentially affecting the prediction of subsurface settlement.展开更多
This study investigates the dynamical behavior of two parallel fluid-conveying pipes by developing a non-planar dynamical model of the two pipes coupled with an intermediate spring. A systematic analysis is conducted ...This study investigates the dynamical behavior of two parallel fluid-conveying pipes by developing a non-planar dynamical model of the two pipes coupled with an intermediate spring. A systematic analysis is conducted to evaluate the effects of spring parameters on the non-planar vibration characteristics and buckling behaviors of the coupled system. The nonlinear governing equations are derived with Hamilton's principle,subsequently discretized through Galerkin's method, and finally numerically solved by the Runge-Kutta algorithm. Based on the linearized equations, an eigenvalue analysis is performed to obtain the coupled frequencies, modal shapes, and critical flow velocities for buckling instability. Quantitative assessments further elucidate the effects of the spring position and stiffness coefficient on the coupled frequencies and critical flow velocities.Nonlinear dynamic analyses reveal the evolution of buckling patterns and bifurcation behaviors between the lateral displacements of the two pipes and the flow velocity. Numerical results indicate that the intermediate spring increases the susceptibility to buckling instability in the out-of-plane direction compared with the in-plane direction. Furthermore, synchronized lateral displacements emerge in both pipes when the flow velocity of one pipe exceeds the critical threshold. This work is expected to provide a theoretical foundation for the stability assessment and vibration analysis in coupled fluid-conveying pipe systems.展开更多
Sodium-ion hybrid capacitors(SICs),which combine the high energy density of batteries with the high power density and long cycle life of capacitors,are considered promising next-generation energy storage devices.Ensur...Sodium-ion hybrid capacitors(SICs),which combine the high energy density of batteries with the high power density and long cycle life of capacitors,are considered promising next-generation energy storage devices.Ensuring the performance of SICs in low-temperature environments is crucial for applications in high-altitude cold regions,where the desolvation process of Na+and the transport process in the solid electrolyte interphase(SEI)are determinant.In this paper,we proposed a multi-ether modulation strategy to construct a solvation sheath with multi-ether participation by modulating the coordination of Na+and solvents.This unique solvation sheath not only reduces the desolvation energy barrier of Na+,but more importantly forms a Na_(2)O-rich inorganic SEI and enhances the ionic dynamics of Na+.Benefiting from the excellent solvation structure design,SICs prepared with this electrolyte can achieve energy density of up to 178 Wh·kg^(-1) and ultra-high power density of 42390 W·kg^(-1) at room temperature.Notably,this SIC delivers record-high energy densities of 149 Wh·kg^(-1) and 119 Wh·kg^(-1) as well as power densities of up to 25200 W·kg^(-1) and 24591 W·kg^(-1) at−20℃ and−40℃,respectively.This work provides new ideas for the development of high-performance SICs for low-temperature operating environments.展开更多
Cold-surge events can lead to temperature drops and strong winds,which then leads to upper-ocean cooling and deepening of the mixed-layer depth,as illustrated in previous studies.In this study,based on the temperature...Cold-surge events can lead to temperature drops and strong winds,which then leads to upper-ocean cooling and deepening of the mixed-layer depth,as illustrated in previous studies.In this study,based on the temperature drop of Shanwei meteorological station,two extreme cold surges and five weak cold invasions in the South China Sea are simulated using an ocean-atmosphere coupled model to investigate their different impacts on the upper-ocean temperature.The diffusion term contributes to the difference in temperature tendency of the upper 20 m,while the advection term contributes to the positive difference from 20 to 80 m of the offshore region and negative difference from 80 to 160 m.In addition,the significant differences are attributed primarily to the influence of the upper-ocean temperature gradient,which subsequently impacts the advection term and results in notable differences in temperature tendency at depths from 80 to 160 m.展开更多
<div style="text-align:justify;"> Titanium alloy materials are widely used in the marine and aviation fields due to their excellent properties. The submersible sailing on the water surface is faster th...<div style="text-align:justify;"> Titanium alloy materials are widely used in the marine and aviation fields due to their excellent properties. The submersible sailing on the water surface is faster than underwater diving, so once an accident occurs, the consequences are unimaginable. Based on the failure criterion of the J-K model, this paper uses finite element simulation software to study the impact of impact velocity and impact angle on the collision response of a titanium alloy cylindrical pressure shell, providing a reference for the deep sea titanium alloy pressure shell. </div>展开更多
<i><span style="font-family:Verdana;">Astragali Radix </span></i><span style="font-family:Verdana;">(AR), the dried root of legumes, belongs to the Qi-invigorating<...<i><span style="font-family:Verdana;">Astragali Radix </span></i><span style="font-family:Verdana;">(AR), the dried root of legumes, belongs to the Qi-invigorating</span><span style="font-family:""> <span style="font-family:Verdana;">herbs in traditional Chinese medicine and plays an important role in the</span><span style="font-family:Verdana;"> treatment of many diseases. In order to understand the mechanism of action of AR extract. We used AR extract to treat M-1, mouse kidney cells, and used transcriptome sequencing technology to detect the genomic transcription level of the cells under the action of AR at different concentrations and times. The results showed that after a low concentration of AR treatments on the cells, the expression of genes related to cell growth and cellular immune response changed significantly, among which multiple genes are related to mitochondrial function, while high concentrations of AR affected the expression of histones and disease-related genes. It showed that the low concentration of AR extract can achieve the effect of invigorating Qi by regulating the function of mitochondria. In addition, several important genes and pathways were identified as potential targets of AR activation. The research not only clarified the main molecular biological mechanism of AR invigorating Qi, but also provided experimental basis and cellular physiology reference for the further clinical application of AR.展开更多
Bentonite is a necessary binder in producing pellets.Its excessive use reduces the iron grade of pellets and increases production costs.Minimizing bentonite dosage is essential for producing high-quality iron ore pell...Bentonite is a necessary binder in producing pellets.Its excessive use reduces the iron grade of pellets and increases production costs.Minimizing bentonite dosage is essential for producing high-quality iron ore pellets.Addressing the gap in the application of organically-intercalated modified bentonite in the pelletizing field,this study introduces an innovative modification process for bentonite that employs the synergistic effect of mechanical force and dimethyl sulfoxide to enhance the intercalation of organic compounds within bentonite,thus significantly enhancing its binding performance.The colloid value and swell capacity of modified bentonite(98.5 m L/3g and 55.0 m L/g)were much higher than the original bentonite(90.5 m L/3g and 17.5 m L/g).With the decrease of bentonite dosage from1.5wt%to 1.0wt%,the drop number of green pellets from a height of 0.5 m and the compressive strengths of roasted pellets using the modified bentonite(6.0 times and 2916 N per pellet)were significantly higher than those of the original bentonite(4.0 times and 2739 N per pellet).This study provides a comprehensive analysis of the intercalation modification mechanism of bentonite,offering crucial technical insights for the development of high-performance modified bentonite as iron ore pellet binders.展开更多
This study investigates the relationship between atmospheric stratification (i.e., static stability given by N^(2)) and the vertical energy transfer of stationary planetary waves, and further illustrates the underlyin...This study investigates the relationship between atmospheric stratification (i.e., static stability given by N^(2)) and the vertical energy transfer of stationary planetary waves, and further illustrates the underlying physical mechanism. Specifically, for the simplified case of constant stratospheric N^(2), the refractive index square of planetary waves has a theoretical tendency to increase first and then decrease with an increased N^(2), whereas the group velocity weakens. Mechanistically, this behavior can be understood as an intensified suppression of vertical isentropic surface displacement caused by meridional heat transport of planetary waves under strong N^(2) conditions. Observational analysis corroborates this finding, demonstrating a reduction in the vertical-propagation velocity of waves with increased N^(2). A linear, quasi- geostrophic, mid-latitude beta-plane model with a constant background westerly wind and a prescribed N^(2) applicable to the stratosphere is used to obtain analytic solutions. In this model, the planetary waves are initiated by steady energy influx from the lower boundary. The analysis indicates that under strong N^(2) conditions, the amplitude of planetary waves can be sufficiently increased by the effective energy convergence due to the slowing vertical energy transfer, resulting in a streamfunction response in this model that contains more energy. For N^(2) with a quasi-linear vertical variation, the results bear a resemblance to the constant case, except that the wave amplitude and oscillating frequency show some vertical variations.展开更多
Marine thin plates are susceptible to welding deformation owing to their low structural stiffness.Therefore,the efficient and accurate prediction of welding deformation is essential for improving welding quality.The t...Marine thin plates are susceptible to welding deformation owing to their low structural stiffness.Therefore,the efficient and accurate prediction of welding deformation is essential for improving welding quality.The traditional thermal elastic-plastic finite element method(TEP-FEM)can accurately predict welding deformation.However,its efficiency is low because of the complex nonlinear transient computation,making it difficult to meet the needs of rapid engineering evaluation.To address this challenge,this study proposes an efficient prediction method for welding deformation in marine thin plate butt welds.This method is based on the coupled temperature gradient-thermal strain method(TG-TSM)that integrates inherent strain theory with a shell element finite element model.The proposed method first extracts the distribution pattern and characteristic value of welding-induced inherent strain through TEP-FEM analysis.This strain is then converted into the equivalent thermal load applied to the shell element model for rapid computation.The proposed method-particularly,the gradual temperature gradient-thermal strain method(GTG-TSM)-achieved improved computational efficiency and consistent precision.Furthermore,the proposed method required much less computation time than the traditional TEP-FEM.Thus,this study lays the foundation for future prediction of welding deformation in more complex marine thin plates.展开更多
AIM: To characterize the expression of members of the transforming growth factor-beta (TGF-β)/Smad/ connective tissue growth factor (CTGF) signaling pathway in the tissue of benign biliary stricture, and to investiga...AIM: To characterize the expression of members of the transforming growth factor-beta (TGF-β)/Smad/ connective tissue growth factor (CTGF) signaling pathway in the tissue of benign biliary stricture, and to investigate the effect of TGF-β signaling pathway in the pathogenesis of benign biliary stricture. METHODS: Paraffin embedded materials from 23 cases of benign biliary stricture were analyzed for members of the TGF-β/Smad/CTGF signaling pathway. TGF-β_1, TβRⅠ, TβRⅡ, Smad4, Smad7 and CTGF protein were detected by immunohistochemical strepto-advidinbiotin complex method, and CTGF mRNA was evaluated by hybridization in situ, while 6 cases of normal bile duct served as controls. The percentages of positive cells were counted. The correlation between TGF-β_1, Smad4 and CTGF was analyzed. RESULTS: The positive expression ratios of TGF-β_1, TβRⅠ , TβRⅡ , Smad4, CTGF and CTGF mRNA in 23 cases with benign biliary stricture were 91.3%, 82.6%, 87.0%, 78.3%, 82.6% and 65.2%, respectively, signifi cantly higher than that in 6 cases of normal bile duct respectively (vs 33.3%, 16.7%, 50.0%, 33.3%, 50.0%, 16.7%, respectively, P < 0.05). The positiveexpression ratio of Smad7 in cases with benign biliary stricture was 70.0%, higher than that in normal bile duct, but this difference is not statistically signifi cant 70.0% vs 50%, P > 0.05). There was a positive correlation between positive expression of TGF-β_1, Smad4 and CTGF in cases with benign biliary stricture. CONCLUSION: The high expression of TGF-β/Smad/ CTGF signaling pathway plays an important role in the pathogenesis of benign biliary stricture.展开更多
The single and combinational effects of cadmium （Cd） and fluoranthene （FLT） on germination, growth and photosynthesis of soybean seedlings were investigated. Exposure to 5, 10, or 15 mg Cd/L or 1, 5, or 10 mg FLT/...The single and combinational effects of cadmium （Cd） and fluoranthene （FLT） on germination, growth and photosynthesis of soybean seedlings were investigated. Exposure to 5, 10, or 15 mg Cd/L or 1, 5, or 10 mg FLT/L individually or in combination significantly decreased germination vigor （3 days） and final germination rate of soybean seeds, except at 1 and 5 mg FLT/L. The results of two-way ANOVA analysis and the Bliss independence model showed that at lower concentrations of FLT （1 mg/L）, the interaction between Cd and FLT on germination was antagonistic, whereas the interaction was synergistic when the concentration of FLT was 5 or 10 mg/L and the concentration of Cd was 15 mg/L. Growth, expressed as dry weight, length of shoot and root, leaf area, and photosynthesis, expressed as net photosynthetic rate, intercellular CO2 concentration, chlorophyll contents and fluorescence of soybean seedlings were also reduced by exposure to 5 or 10 mg Cd/L or 1 or 5 mg FLT/L, singly or jointly. Significant antagonistic effects of exposure to 5 or 10 mg Cd/L or 1 or 5 mg FLT/L on shoot growth and photosynthesis were observed, whereas synergy and antagonism of Cd and FLT were both observed for root growth.展开更多
An Al−3.6Cu−1Li alloy was subjected to room temperature rolling and cryorolling to investigate their effects on microstructure evolution and mechanical properties.The microstructure and aging characteristics of the ro...An Al−3.6Cu−1Li alloy was subjected to room temperature rolling and cryorolling to investigate their effects on microstructure evolution and mechanical properties.The microstructure and aging characteristics of the room temperature-rolled and the cryorolled alloys with 70%and 90%of thickness reductions were studied by microstructure analysis and mechanical tests.The samples subjected to cryorolling with 90%of thickness reduction have high strength and good toughness.This is mainly due to the inhibition of dynamic recovery and the accumulation of high-density dislocations in cryorolled samples.In addition,the artificial aging reveals that the temperature at which peak hardness is attained is inversely proportional to the deformation amount and directly proportional to the rolling temperature.Moreover,bright field images of cryorolled samples after aging indicate the existence of T1(Al2CuLi)precipitates.This suggests that the high stored strain energy enhances the aging kinetics of the alloy,which further promotes the nucleation of T1 phases.展开更多
Objective： To assess the clinical features, survival and prognostic factors of primary testicular diffuse large B-cell lymphoma （DLBCL）. Methods： A retrospective study of 37 patients with primary testicular DLBCL ...Objective： To assess the clinical features, survival and prognostic factors of primary testicular diffuse large B-cell lymphoma （DLBCL）. Methods： A retrospective study of 37 patients with primary testicular DLBCL was carried out from November 2003 to May 2012. Their clinical features, survival and prognostic factors were analyzed. Results： During a median follow-up period of 39.8 months （5.4-93.0 months）, the median progression-free survival （PFS） was 26.2 months （95% CI：0-65 months） and the 3-year overall survival （OS） rate was 78.4%. Within the whole cohort, the factors significantly associated with a superior PFS were limited stage （stage Ⅰ/Ⅱ）, lactate dehydrogenase （LDH） ≤245 U/L, international prognostic index （IPI） ≤1, primary tumor diameter 〈7.5 cm, and patients who had complete response （CR） and received doxoruhicin-contained chemotherapy （P〈0.05）. There was a trend toward superior outcome for patients who received combined therapy （surgery/ chemotherapy/radiotherapy） （P=0.055）. Patients who had CR, primary tumor diameter 〈7.5 cm and IPI score ≤1 were significantly associated with longer PFS at multivariate analysis. Conclusions： Primary testicular DLBCL had poorer survival. CR, primary tumor diameter and IPI were independent prognostic factors. The combined therapy of orchectomy, doxorubicin-contained chemotherapy and contralateral testicular radiotherapy （RT） seemed to improve survival.展开更多
AIM: To examine the correlation of phosphatidylinositol 3-kinase (PIK3) CB expression with preoperative radiotherapy response in patients with stage II/III rectal adenocarcinoma.
Cervicogenic headache(CEH)has been recognized as a unique category of headache that can be difficult to diagnose and treat.In China,CEH patients are managed by many different specialties,and the treatment plans remain...Cervicogenic headache(CEH)has been recognized as a unique category of headache that can be difficult to diagnose and treat.In China,CEH patients are managed by many different specialties,and the treatment plans remain controversial.Therefore,there is a great need for comprehensive evidence-based Chinese experts’recommendations for the management of CEH.The Chinese Association for the Study of Pain asked an expert panel to develop recommendations for a series of questions that are essential for daily clinical management of patients with CEH.A group of multidisciplinary Chinese Association for the Study of Pain experts identified the clinically relevant topics in CEH.A systematic review of the literature was performed,and evidence supporting the benefits and harms for the management of CEH was summarized.Twenty-four recommendations were finally developed through expert consensus voting for evidence quality and recommendation strength.We hope this guideline provides direction for clinicians and patients making treatment decisions for the management of CEH.展开更多
In this paper, the nonlinear dynamical behavior of two coupled pipes conveying pulsating fluid is studied. The connection between the two pipes is considered as a distributed linear spring. Based on this consideration...In this paper, the nonlinear dynamical behavior of two coupled pipes conveying pulsating fluid is studied. The connection between the two pipes is considered as a distributed linear spring. Based on this consideration, the equations of motion of the coupled two-pipe system are obtained. The two coupled nonlinear partial differential equations, discretized using the fourth- order Galerkin method, are solved by a fourth-order Runge-Kutta integration algorithm. Results show that the connection stiffness has a significant effect on the dynamical behavior of the coupled system. It is found that for some parameter values the motion types of the two pipes might be synchronous.展开更多
基金supported by the National Natural Science Foundation of China (Nos. 11622216 and 51409134)
文摘The nonlinear forced vibrations of a cantilevered pipe conveying fluid under base excitations are explored by means of the full nonlinear equation of motion, and the fourth- order Runge-Kutta integration algorithm is used as a numerical tool to solve the discretized equations. The self-excited vibration is briefly discussed first, focusing on the effect of flow velocity on the stability and post-flutter dynamical behavior of the pipe system with parameters close to those in previous experiments. Then, the nonlinear forced vibrations are examined using several concrete examples by means of frequency response diagrams and phase-plane plots. It shows that, at low flow velocity, the resonant amplitude near the first-mode natural frequency is larger than its counterpart near the second-mode natural frequency. The second-mode frequency response curve clearly displays a softening-type behavior with hysteresis phenomenon, while the first-mode frequency response curve almost maintains its neutrality. At moderate flow velocity, interestingly, the first-mode resonance response diminishes and the hysteresis phenomenon of the second-mode response disappears. At high flow velocity beyond the flutter threshold, the frequency response curve would exhibit a quenching-like behavior. When the excitation frequency is increased through the quenching point, the response of the pipe may shift from quasiperiodic to periodic. The results obtained in the present work highlight the dramatic influence of internal fluid flow on the nonlinear forced vibrations of slender Pipes.
文摘The linkage between Qi and mitochondria was investigated by exploring the effect of Traditional Chinese Medicine (TCM) Qi-invigorating herbs on mitochondrial function at the biochemical and molecular levels. Three Chinese herbs (<i></span><i><span style="font-family:Verdana;">Astragali radix</span></i><span style="font-family:Verdana;">,</span><i><span style="font-family:Verdana;"> Herba cistanche</span></i><span style="font-family:Verdana;">, </span><i><span style="font-family:Verdana;">Panax ginseng</span></i><span style="font-family:Verdana;"></i>) were used to treat cultured mouse kidney cells and the generation of adenosine triphosphate (ATP) was measured. The Qi-invigorating herb, <i></span><i><span style="font-family:Verdana;">Astragali radix</span></i><span style="font-family:Verdana;"></i>, was selected for further </span></span><span style="font-family:""><span style="font-family:Verdana;">study using additional biological and molecular parameters, including ATP, reactive oxygen species (ROS), mitochondrial membrane potential (MMP),</span><span><span style="font-family:Verdana;"> mtDNA copies, superoxide dismutase (SOD), glutathione (GSH), cell growth, cell viability and transcriptomes. We also chose two concentrations of <i></span><i><span style="font-family:Verdana;">Astragali radix</span></i><span style="font-family:Verdana;"></i> to study the hormetic effect. The results indicated that: 1) Qi-invigorating herbs have significant effects on the function of mitochondria, with ATP production and the antioxidant capacity being significantly enhanced, and ROS le</span></span><span style="font-family:Verdana;">vels being reduced, allowing for a more optimal oxidation environment. The effect of the herbs followed a hormetic curve with a stimulating effect at lower</span><span> </span><span style="font-family:Verdana;">doses but an inhibiting effect at high doses;2) The growth of the cells was not</span><span> </span><span style="font-family:Verdana;">affected despite numerous biochemical changes associated with mitochondrial</span><span> </span><span style="font-family:Verdana;">function, indicating the powerful ability of mitochondria to maintain cellular homeostasis;3) The up-regulation of NOCT gene, related to nicotinamide adenine dinucleotide (NADH) synthesis, offers a molecular basis for the ATP-promoting effect of the Qi-invigorating herbs. This work provides additional insight into the efficacy of TCM herbs from a western perspective.
基金supported by the National Natural Science Foundation of China(U1507111).
文摘The phase equilibria relationship of the system RbCl-PEG6000-H2O were investigated at temperatures of 288.2,298.2,and 308.2 K,the compositions of solid-liquid equilibria(SLE)and liquid-liquid equilibria(LLE)were determined.The complete phase diagrams,binodal curve diagrams,and tie-line diagrams were all plotted.Results show that both solid-liquid equilibria and liquid-liquid equilibria relationships at each studied temperature.The complete phase diagrams at 288.2 K,298.2 K and 308.2 K consist of six phase regions:unsaturated liquid region(L),two saturated solutions with one solid phase of RbCl(L_S),one saturated liquid phase with two solid phases of PEG6000 and RbCl(2S+L),an aqueous two-phase region(2L),and a region with two liquids and one solid phase of RbCl(2L_S).With the increase in temperature,the layering ability of the aqueous two-phase system increases,and both regions(2L)and(2L_S)increase.The binodal curves were fitted using the nonlinear equations proposed by Mistry,Hu,and Jayapal.Additionally,the tie-line data were correlated with the Othmer-Tobias,Bancroft,Hand,and Bachman equations.The liquid-liquid equilibria at 288.2 K,298.2 K and 308.2 K were calculated using the NRTL model.The findings confirm that the experimental and calculated values are in close agreement,demonstrating the model’s effectiveness in representing the system’s behavior.
基金supported by the Natural Science Foundation of Beijing Municipality(No.8222004),Chinathe National Natural Science Foundation of China(No.51978019)+3 种基金the Natural Science Foundation of Henan Province(No.252300420445),Chinathe Doctoral Research Initiation Fund of Henan University of Science and Technology(No.4007/13480062),Chinathe Henan Postdoctoral Foundation(No.13554005),Chinathe Joint Fund of Science and Technology R&D Program of Henan Province(No.232103810082),China。
文摘Sandy cobble soil exhibits pronounced heterogeneity.The assessment of the uncertainty surrounding its properties is crucial for the analysis of settlement characteristics resulting from volume loss during shield tunnelling.In this study,a series of probabilistic analyses of surface and subsurface settlements was conducted considering the spatial variability of the friction angle and reference stiffness modulus,under different volumetric block proportions(Pv)and tunnel volume loss rates(ηt).The non-intrusive random finite difference method was used to investigate the probabilistic characteristics of maximum surface settlement,width of subsurface settlement trough,maximum subsurface settlement,and subsurface soil volume loss rate through Monte Carlo simulations.Additionally,a comparison between stochastic and deterministic analysis results is presented to underscore the significance of probabilistic analysis.Parametric analyses were subsequently conducted to investigate the impacts of the key input parameters in random fields on the settlement characteristics.The results indicate that scenarios with higher Pv or greaterηt result in a higher dispersion of stochastic analysis results.Neglecting the spatial variability of soil properties and relying solely on the mean values of material parameters for deterministic analysis may result in an underestimation of surface and subsurface settlements.From a probabilistic perspective,deterministic analysis alone may prove inadequate in accurately capturing the volumetric deformation mode of the soil above the tunnel crown,potentially affecting the prediction of subsurface settlement.
基金supported by the National Natural Science Foundation of China(Nos.12325201,12272140,and 12322201)。
文摘This study investigates the dynamical behavior of two parallel fluid-conveying pipes by developing a non-planar dynamical model of the two pipes coupled with an intermediate spring. A systematic analysis is conducted to evaluate the effects of spring parameters on the non-planar vibration characteristics and buckling behaviors of the coupled system. The nonlinear governing equations are derived with Hamilton's principle,subsequently discretized through Galerkin's method, and finally numerically solved by the Runge-Kutta algorithm. Based on the linearized equations, an eigenvalue analysis is performed to obtain the coupled frequencies, modal shapes, and critical flow velocities for buckling instability. Quantitative assessments further elucidate the effects of the spring position and stiffness coefficient on the coupled frequencies and critical flow velocities.Nonlinear dynamic analyses reveal the evolution of buckling patterns and bifurcation behaviors between the lateral displacements of the two pipes and the flow velocity. Numerical results indicate that the intermediate spring increases the susceptibility to buckling instability in the out-of-plane direction compared with the in-plane direction. Furthermore, synchronized lateral displacements emerge in both pipes when the flow velocity of one pipe exceeds the critical threshold. This work is expected to provide a theoretical foundation for the stability assessment and vibration analysis in coupled fluid-conveying pipe systems.
基金support from National Outstanding Youth Science Fund(52222314)Near Space Technology and Industry Guidance Fund Project(LKJJ-2023010-01)+3 种基金CNPC Innovation Found(2021DQ02-1001)Dalian Outstanding Youth Science and Technology Talent Project(2023RJ006)Dalian Science and Technology Innovation Project(2022JJ12GX022)Xinghai Talent Cultivation Plan(X20200303).
文摘Sodium-ion hybrid capacitors(SICs),which combine the high energy density of batteries with the high power density and long cycle life of capacitors,are considered promising next-generation energy storage devices.Ensuring the performance of SICs in low-temperature environments is crucial for applications in high-altitude cold regions,where the desolvation process of Na+and the transport process in the solid electrolyte interphase(SEI)are determinant.In this paper,we proposed a multi-ether modulation strategy to construct a solvation sheath with multi-ether participation by modulating the coordination of Na+and solvents.This unique solvation sheath not only reduces the desolvation energy barrier of Na+,but more importantly forms a Na_(2)O-rich inorganic SEI and enhances the ionic dynamics of Na+.Benefiting from the excellent solvation structure design,SICs prepared with this electrolyte can achieve energy density of up to 178 Wh·kg^(-1) and ultra-high power density of 42390 W·kg^(-1) at room temperature.Notably,this SIC delivers record-high energy densities of 149 Wh·kg^(-1) and 119 Wh·kg^(-1) as well as power densities of up to 25200 W·kg^(-1) and 24591 W·kg^(-1) at−20℃ and−40℃,respectively.This work provides new ideas for the development of high-performance SICs for low-temperature operating environments.
基金jointly supported by the Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)[grant number SML2023SP240]the National Natural Science Foundation of China[grant number 92158204]。
文摘Cold-surge events can lead to temperature drops and strong winds,which then leads to upper-ocean cooling and deepening of the mixed-layer depth,as illustrated in previous studies.In this study,based on the temperature drop of Shanwei meteorological station,two extreme cold surges and five weak cold invasions in the South China Sea are simulated using an ocean-atmosphere coupled model to investigate their different impacts on the upper-ocean temperature.The diffusion term contributes to the difference in temperature tendency of the upper 20 m,while the advection term contributes to the positive difference from 20 to 80 m of the offshore region and negative difference from 80 to 160 m.In addition,the significant differences are attributed primarily to the influence of the upper-ocean temperature gradient,which subsequently impacts the advection term and results in notable differences in temperature tendency at depths from 80 to 160 m.
文摘<div style="text-align:justify;"> Titanium alloy materials are widely used in the marine and aviation fields due to their excellent properties. The submersible sailing on the water surface is faster than underwater diving, so once an accident occurs, the consequences are unimaginable. Based on the failure criterion of the J-K model, this paper uses finite element simulation software to study the impact of impact velocity and impact angle on the collision response of a titanium alloy cylindrical pressure shell, providing a reference for the deep sea titanium alloy pressure shell. </div>
文摘<i><span style="font-family:Verdana;">Astragali Radix </span></i><span style="font-family:Verdana;">(AR), the dried root of legumes, belongs to the Qi-invigorating</span><span style="font-family:""> <span style="font-family:Verdana;">herbs in traditional Chinese medicine and plays an important role in the</span><span style="font-family:Verdana;"> treatment of many diseases. In order to understand the mechanism of action of AR extract. We used AR extract to treat M-1, mouse kidney cells, and used transcriptome sequencing technology to detect the genomic transcription level of the cells under the action of AR at different concentrations and times. The results showed that after a low concentration of AR treatments on the cells, the expression of genes related to cell growth and cellular immune response changed significantly, among which multiple genes are related to mitochondrial function, while high concentrations of AR affected the expression of histones and disease-related genes. It showed that the low concentration of AR extract can achieve the effect of invigorating Qi by regulating the function of mitochondria. In addition, several important genes and pathways were identified as potential targets of AR activation. The research not only clarified the main molecular biological mechanism of AR invigorating Qi, but also provided experimental basis and cellular physiology reference for the further clinical application of AR.
基金financial support by the National Key Research and Development Program of China(No.2023YFC2907801)the Hunan Provincial Natural Science Foundation of China(No.2023JJ40760)the Scientific and Technological Project of Yunnan Precious Metals Laboratory,China(No.YPML-2023050276)。
文摘Bentonite is a necessary binder in producing pellets.Its excessive use reduces the iron grade of pellets and increases production costs.Minimizing bentonite dosage is essential for producing high-quality iron ore pellets.Addressing the gap in the application of organically-intercalated modified bentonite in the pelletizing field,this study introduces an innovative modification process for bentonite that employs the synergistic effect of mechanical force and dimethyl sulfoxide to enhance the intercalation of organic compounds within bentonite,thus significantly enhancing its binding performance.The colloid value and swell capacity of modified bentonite(98.5 m L/3g and 55.0 m L/g)were much higher than the original bentonite(90.5 m L/3g and 17.5 m L/g).With the decrease of bentonite dosage from1.5wt%to 1.0wt%,the drop number of green pellets from a height of 0.5 m and the compressive strengths of roasted pellets using the modified bentonite(6.0 times and 2916 N per pellet)were significantly higher than those of the original bentonite(4.0 times and 2739 N per pellet).This study provides a comprehensive analysis of the intercalation modification mechanism of bentonite,offering crucial technical insights for the development of high-performance modified bentonite as iron ore pellet binders.
基金supported by the National Natural Science Foundation of China(Grant No.42261134532,42405059,and U2342212)。
文摘This study investigates the relationship between atmospheric stratification (i.e., static stability given by N^(2)) and the vertical energy transfer of stationary planetary waves, and further illustrates the underlying physical mechanism. Specifically, for the simplified case of constant stratospheric N^(2), the refractive index square of planetary waves has a theoretical tendency to increase first and then decrease with an increased N^(2), whereas the group velocity weakens. Mechanistically, this behavior can be understood as an intensified suppression of vertical isentropic surface displacement caused by meridional heat transport of planetary waves under strong N^(2) conditions. Observational analysis corroborates this finding, demonstrating a reduction in the vertical-propagation velocity of waves with increased N^(2). A linear, quasi- geostrophic, mid-latitude beta-plane model with a constant background westerly wind and a prescribed N^(2) applicable to the stratosphere is used to obtain analytic solutions. In this model, the planetary waves are initiated by steady energy influx from the lower boundary. The analysis indicates that under strong N^(2) conditions, the amplitude of planetary waves can be sufficiently increased by the effective energy convergence due to the slowing vertical energy transfer, resulting in a streamfunction response in this model that contains more energy. For N^(2) with a quasi-linear vertical variation, the results bear a resemblance to the constant case, except that the wave amplitude and oscillating frequency show some vertical variations.
基金Supported by the National Natural Science Foundation of China under Grant No.51975138the High-Tech Ship Scientific Research Project from the Ministry of Industry and Information Technology under Grant No.CJ05N20the National Defense Basic Research Project under Grant No.JCKY2023604C006.
文摘Marine thin plates are susceptible to welding deformation owing to their low structural stiffness.Therefore,the efficient and accurate prediction of welding deformation is essential for improving welding quality.The traditional thermal elastic-plastic finite element method(TEP-FEM)can accurately predict welding deformation.However,its efficiency is low because of the complex nonlinear transient computation,making it difficult to meet the needs of rapid engineering evaluation.To address this challenge,this study proposes an efficient prediction method for welding deformation in marine thin plate butt welds.This method is based on the coupled temperature gradient-thermal strain method(TG-TSM)that integrates inherent strain theory with a shell element finite element model.The proposed method first extracts the distribution pattern and characteristic value of welding-induced inherent strain through TEP-FEM analysis.This strain is then converted into the equivalent thermal load applied to the shell element model for rapid computation.The proposed method-particularly,the gradual temperature gradient-thermal strain method(GTG-TSM)-achieved improved computational efficiency and consistent precision.Furthermore,the proposed method required much less computation time than the traditional TEP-FEM.Thus,this study lays the foundation for future prediction of welding deformation in more complex marine thin plates.
基金The grant from Shaanxi Science and Technology Project, No. 2002K10-G8
文摘AIM: To characterize the expression of members of the transforming growth factor-beta (TGF-β)/Smad/ connective tissue growth factor (CTGF) signaling pathway in the tissue of benign biliary stricture, and to investigate the effect of TGF-β signaling pathway in the pathogenesis of benign biliary stricture. METHODS: Paraffin embedded materials from 23 cases of benign biliary stricture were analyzed for members of the TGF-β/Smad/CTGF signaling pathway. TGF-β_1, TβRⅠ, TβRⅡ, Smad4, Smad7 and CTGF protein were detected by immunohistochemical strepto-advidinbiotin complex method, and CTGF mRNA was evaluated by hybridization in situ, while 6 cases of normal bile duct served as controls. The percentages of positive cells were counted. The correlation between TGF-β_1, Smad4 and CTGF was analyzed. RESULTS: The positive expression ratios of TGF-β_1, TβRⅠ , TβRⅡ , Smad4, CTGF and CTGF mRNA in 23 cases with benign biliary stricture were 91.3%, 82.6%, 87.0%, 78.3%, 82.6% and 65.2%, respectively, signifi cantly higher than that in 6 cases of normal bile duct respectively (vs 33.3%, 16.7%, 50.0%, 33.3%, 50.0%, 16.7%, respectively, P < 0.05). The positiveexpression ratio of Smad7 in cases with benign biliary stricture was 70.0%, higher than that in normal bile duct, but this difference is not statistically signifi cant 70.0% vs 50%, P > 0.05). There was a positive correlation between positive expression of TGF-β_1, Smad4 and CTGF in cases with benign biliary stricture. CONCLUSION: The high expression of TGF-β/Smad/ CTGF signaling pathway plays an important role in the pathogenesis of benign biliary stricture.
基金supported by the National Natural Science Foundation of China (No. 41071355, 41171394)the National International Cooperation Program of China (No. 2012DFA91150)+1 种基金supported by the Einstein Professorship Program of the Chinese Academy of Sciencesthe Canada Research Chair Program
文摘The single and combinational effects of cadmium （Cd） and fluoranthene （FLT） on germination, growth and photosynthesis of soybean seedlings were investigated. Exposure to 5, 10, or 15 mg Cd/L or 1, 5, or 10 mg FLT/L individually or in combination significantly decreased germination vigor （3 days） and final germination rate of soybean seeds, except at 1 and 5 mg FLT/L. The results of two-way ANOVA analysis and the Bliss independence model showed that at lower concentrations of FLT （1 mg/L）, the interaction between Cd and FLT on germination was antagonistic, whereas the interaction was synergistic when the concentration of FLT was 5 or 10 mg/L and the concentration of Cd was 15 mg/L. Growth, expressed as dry weight, length of shoot and root, leaf area, and photosynthesis, expressed as net photosynthetic rate, intercellular CO2 concentration, chlorophyll contents and fluorescence of soybean seedlings were also reduced by exposure to 5 or 10 mg Cd/L or 1 or 5 mg FLT/L, singly or jointly. Significant antagonistic effects of exposure to 5 or 10 mg Cd/L or 1 or 5 mg FLT/L on shoot growth and photosynthesis were observed, whereas synergy and antagonism of Cd and FLT were both observed for root growth.
基金Project(2019YFB2006500)supported by the National Key Research and Development Program of ChinaProject(51674303)supported by the National Natural Science Foundation of China+2 种基金Project(2018RS3015)supported by the Huxiang High-Level Talent Gathering Project of Hunan Province,ChinaProject(2019CX006)supported by the Innovation Driven Program of Central South University,ChinaProject supported by the Research Fund of the Key Laboratory of High Performance Complex Manufacturing at Central South University,China。
文摘An Al−3.6Cu−1Li alloy was subjected to room temperature rolling and cryorolling to investigate their effects on microstructure evolution and mechanical properties.The microstructure and aging characteristics of the room temperature-rolled and the cryorolled alloys with 70%and 90%of thickness reductions were studied by microstructure analysis and mechanical tests.The samples subjected to cryorolling with 90%of thickness reduction have high strength and good toughness.This is mainly due to the inhibition of dynamic recovery and the accumulation of high-density dislocations in cryorolled samples.In addition,the artificial aging reveals that the temperature at which peak hardness is attained is inversely proportional to the deformation amount and directly proportional to the rolling temperature.Moreover,bright field images of cryorolled samples after aging indicate the existence of T1(Al2CuLi)precipitates.This suggests that the high stored strain energy enhances the aging kinetics of the alloy,which further promotes the nucleation of T1 phases.
文摘Objective： To assess the clinical features, survival and prognostic factors of primary testicular diffuse large B-cell lymphoma （DLBCL）. Methods： A retrospective study of 37 patients with primary testicular DLBCL was carried out from November 2003 to May 2012. Their clinical features, survival and prognostic factors were analyzed. Results： During a median follow-up period of 39.8 months （5.4-93.0 months）, the median progression-free survival （PFS） was 26.2 months （95% CI：0-65 months） and the 3-year overall survival （OS） rate was 78.4%. Within the whole cohort, the factors significantly associated with a superior PFS were limited stage （stage Ⅰ/Ⅱ）, lactate dehydrogenase （LDH） ≤245 U/L, international prognostic index （IPI） ≤1, primary tumor diameter 〈7.5 cm, and patients who had complete response （CR） and received doxoruhicin-contained chemotherapy （P〈0.05）. There was a trend toward superior outcome for patients who received combined therapy （surgery/ chemotherapy/radiotherapy） （P=0.055）. Patients who had CR, primary tumor diameter 〈7.5 cm and IPI score ≤1 were significantly associated with longer PFS at multivariate analysis. Conclusions： Primary testicular DLBCL had poorer survival. CR, primary tumor diameter and IPI were independent prognostic factors. The combined therapy of orchectomy, doxorubicin-contained chemotherapy and contralateral testicular radiotherapy （RT） seemed to improve survival.
基金Supported by Grants from the National Natural Science Foundation of China No.30872923the Peking University People’s Hospital Research and Development Fund No.RDB2007-47,No.RDK2008-01 and No.RDB2011-25
文摘AIM: To examine the correlation of phosphatidylinositol 3-kinase (PIK3) CB expression with preoperative radiotherapy response in patients with stage II/III rectal adenocarcinoma.
文摘Cervicogenic headache(CEH)has been recognized as a unique category of headache that can be difficult to diagnose and treat.In China,CEH patients are managed by many different specialties,and the treatment plans remain controversial.Therefore,there is a great need for comprehensive evidence-based Chinese experts’recommendations for the management of CEH.The Chinese Association for the Study of Pain asked an expert panel to develop recommendations for a series of questions that are essential for daily clinical management of patients with CEH.A group of multidisciplinary Chinese Association for the Study of Pain experts identified the clinically relevant topics in CEH.A systematic review of the literature was performed,and evidence supporting the benefits and harms for the management of CEH was summarized.Twenty-four recommendations were finally developed through expert consensus voting for evidence quality and recommendation strength.We hope this guideline provides direction for clinicians and patients making treatment decisions for the management of CEH.
基金Project supported by the National Natural Science Foundation of China(Nos.11172107 and 11172109)the Program for New Century Excellent Talents in University(No.NCET-11-0183)
文摘In this paper, the nonlinear dynamical behavior of two coupled pipes conveying pulsating fluid is studied. The connection between the two pipes is considered as a distributed linear spring. Based on this consideration, the equations of motion of the coupled two-pipe system are obtained. The two coupled nonlinear partial differential equations, discretized using the fourth- order Galerkin method, are solved by a fourth-order Runge-Kutta integration algorithm. Results show that the connection stiffness has a significant effect on the dynamical behavior of the coupled system. It is found that for some parameter values the motion types of the two pipes might be synchronous.
