The research on gas-liquid multiphase reactions using micro reactors is becoming increasingly widespread, given their excellent mass transfer performance. Establishing an accurate and reliable method to measure the ga...The research on gas-liquid multiphase reactions using micro reactors is becoming increasingly widespread, given their excellent mass transfer performance. Establishing an accurate and reliable method to measure the gas-liquid mass transfer performance of micro reactors is crucial for evaluating and optimizing the design of micro reactor structure. In this paper, the physical absorption method of aqueous solution-CO_(2) and the chemical absorption method of sodium carbonate solution-CO_(2) were proposed. By analyzing the chemical reaction equilibrium during the absorption process, the relationship between the mass transfer of CO_(2) and the solubility of hydroxide ions in the solution was established, and the total gas-liquid mass transfer coefficient was immediately obtained by measuring the p H value. The corresponding testing platform and process have been established based on the characteristics of the proposed method to ensure fast and accurate measurement. In addition, the chemical absorption method takes into account temperature factors that were not previously considered. The volumetric mass transfer coefficient measured by these two methods is in the same range as those measured by other methods using the same microchannel structure in previous literature. The methods have the advantages of low equipment cost, faster measurement speed, and simpler procedures, which can facilitate its wide application to the evaluation of the mass transfer performance and hence can guide the structure optimization of microchannel reactors.展开更多
Copper （II） dicarboxylate, MIL-53, metal-organic framework synthesized hydrothermally has been used for the first time as an adsorbent for methane gas adsorption. Methane adsorption capacity of MIL-53（Cu） was incr...Copper （II） dicarboxylate, MIL-53, metal-organic framework synthesized hydrothermally has been used for the first time as an adsorbent for methane gas adsorption. Methane adsorption capacity of MIL-53（Cu） was increased to about 8.52 mmol·g-1 at 298 K and 35 bar for methane storage. The adsorbent was characterized by X-ray diffraction （XRD）, Brunauer-Emmet-Teller （BET） method, Fourier transform infrared （FT-IR）, thermo gravimetric analysis （TGA） and scanning electron microscopy （SEM）. The adsorption property of CH4, on MIL-53（Cu） was investigated by volumetric measurement. The enhancement of CH4 adsorption capacity of MIL-53（Cu） is attributed to the increase of micropore volume of MIL-53（Cu）.展开更多
Background： White matter lesions （WMLs） are common findings in brain magnetic resonance imaging （MRI） and are strongly associated with stroke incidence, recurrence, and prognosis. However, the relationship betwee...Background： White matter lesions （WMLs） are common findings in brain magnetic resonance imaging （MRI） and are strongly associated with stroke incidence, recurrence, and prognosis. However, the relationship between WMLs and transient ischemic attacks （TIAs） is not well established. This study aimed to determine the clinical significance of WMLs in patients with TIA. Methods： A total of 181 consecutive inpatients with first-ever TIA were enrolled. Brain MRls within 2 days of symptom onset were used to measure WML volumes. Recurrent vascular events within 1 year of TIA onset were assessed. The relationship between WMLs and recurrent risk of vascular events was determined by a multivariate logistic regression. Results： WMLs were identified in 104 patients （57.5%）. Age and ratio of hypertension were significantly different between patients with and without WMLs. The incidence of vascular events in patients with WMLs significantly increased in comparison to those without WMLs （21.15% vs. 5.19%, 95% confidence interval [CI]： 1.18-[ 5.20, P = 0.027） after controlling for cont／~unders. Furthermore, distributions of WML loads were found to be different between patients who developed vascular events and those who did not. WML volumes were demonstrated to be correlated with recurrent risks, and the fourth quartile of WML volumes led to an 8.5-fold elevation of recurrent risk of vascular events compared with the first quartile （95% CI： 1.52-47.65, P = 0.015） alier adjusting for hyperlipidemia. Conclusion： WMLs occur frequently in patients with T1A and are associated wiila the high risk of recurrent vascular events, suggesting a predictive neuroimaging marker for TIA outcomes.展开更多
文摘The research on gas-liquid multiphase reactions using micro reactors is becoming increasingly widespread, given their excellent mass transfer performance. Establishing an accurate and reliable method to measure the gas-liquid mass transfer performance of micro reactors is crucial for evaluating and optimizing the design of micro reactor structure. In this paper, the physical absorption method of aqueous solution-CO_(2) and the chemical absorption method of sodium carbonate solution-CO_(2) were proposed. By analyzing the chemical reaction equilibrium during the absorption process, the relationship between the mass transfer of CO_(2) and the solubility of hydroxide ions in the solution was established, and the total gas-liquid mass transfer coefficient was immediately obtained by measuring the p H value. The corresponding testing platform and process have been established based on the characteristics of the proposed method to ensure fast and accurate measurement. In addition, the chemical absorption method takes into account temperature factors that were not previously considered. The volumetric mass transfer coefficient measured by these two methods is in the same range as those measured by other methods using the same microchannel structure in previous literature. The methods have the advantages of low equipment cost, faster measurement speed, and simpler procedures, which can facilitate its wide application to the evaluation of the mass transfer performance and hence can guide the structure optimization of microchannel reactors.
文摘Copper （II） dicarboxylate, MIL-53, metal-organic framework synthesized hydrothermally has been used for the first time as an adsorbent for methane gas adsorption. Methane adsorption capacity of MIL-53（Cu） was increased to about 8.52 mmol·g-1 at 298 K and 35 bar for methane storage. The adsorbent was characterized by X-ray diffraction （XRD）, Brunauer-Emmet-Teller （BET） method, Fourier transform infrared （FT-IR）, thermo gravimetric analysis （TGA） and scanning electron microscopy （SEM）. The adsorption property of CH4, on MIL-53（Cu） was investigated by volumetric measurement. The enhancement of CH4 adsorption capacity of MIL-53（Cu） is attributed to the increase of micropore volume of MIL-53（Cu）.
文摘Background： White matter lesions （WMLs） are common findings in brain magnetic resonance imaging （MRI） and are strongly associated with stroke incidence, recurrence, and prognosis. However, the relationship between WMLs and transient ischemic attacks （TIAs） is not well established. This study aimed to determine the clinical significance of WMLs in patients with TIA. Methods： A total of 181 consecutive inpatients with first-ever TIA were enrolled. Brain MRls within 2 days of symptom onset were used to measure WML volumes. Recurrent vascular events within 1 year of TIA onset were assessed. The relationship between WMLs and recurrent risk of vascular events was determined by a multivariate logistic regression. Results： WMLs were identified in 104 patients （57.5%）. Age and ratio of hypertension were significantly different between patients with and without WMLs. The incidence of vascular events in patients with WMLs significantly increased in comparison to those without WMLs （21.15% vs. 5.19%, 95% confidence interval [CI]： 1.18-[ 5.20, P = 0.027） after controlling for cont／~unders. Furthermore, distributions of WML loads were found to be different between patients who developed vascular events and those who did not. WML volumes were demonstrated to be correlated with recurrent risks, and the fourth quartile of WML volumes led to an 8.5-fold elevation of recurrent risk of vascular events compared with the first quartile （95% CI： 1.52-47.65, P = 0.015） alier adjusting for hyperlipidemia. Conclusion： WMLs occur frequently in patients with T1A and are associated wiila the high risk of recurrent vascular events, suggesting a predictive neuroimaging marker for TIA outcomes.
