The systematic research about the adsorption desulfurization and competitive behavior from 1-hexene over cesium-exchanged Y zeolites has been investigated. The structural properties of the adsorbents were characterize...The systematic research about the adsorption desulfurization and competitive behavior from 1-hexene over cesium-exchanged Y zeolites has been investigated. The structural properties of the adsorbents were characterized by X-ray diffraction（XRD）, N_2 sorption（BET） and thermal analysis（TGA）. The effects of calcination temperature, calcination atmosphere, and adsorption temperature were studied by the dynamic and static tests. The competitive adsorption mechanisms between thiophene and 1-hexene were studied by in-situ Fourier transform infrared spectroscopy（in-situ FTIR） and temperature-programmed desorption（TPD）. CsY adsorbents exhibited high selectivity for thiophene even when a large amount of olefins exist.In-situ FTIR spectra of thiophene and 1-hexene adsorption indicated that both thiophene and 1-hexene were mainly adsorbed on CsY via π-complexation. The higher desorption activated energy and higher adsorption heat of thiophene than 1-hexene obtained by thiophene-TPD and hexene-TPD has revealed that thiophene is adsorbed more strongly in CsY adsorbents than 1-hexene.展开更多
Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2)C-M_(t)C composite ceramic was prepared by hot press sintering,with the Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2)C high-entropy carbide as the main phase.Secondary phase M_(x)C(M...Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2)C-M_(t)C composite ceramic was prepared by hot press sintering,with the Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2)C high-entropy carbide as the main phase.Secondary phase M_(x)C(M=Ti,Zr,Hf,Nb,Ta) was found to be distributed relatively uniform in the composite ceramic.The oxidation behavior of the ceramic was examined after exposure to 923 K and 1173 K.Morphology of the surface and cross sections of all oxidation samples were observed.The characteristics of the oxidation behavior of the high-entropy carbide and the secondary phase M_(x)C were compared and analyzed.The secondary phases(such as Ti-rich carbide or Hf-rich carbide) in the material were seriously oxidized at 923 K and 1173 K,which reflects the superior oxidation performance of the high-entropy carbide.The nano high-entropy oxides with Ti,Zr,Hf,Nb,Ta,and O elements were discovered by oxidation of the composite ceramic.This research will help deepen the understanding of the oxidation mechanism of high-entropy carbide and composite ceramic.展开更多
The presence of lightning impulses(LIs)on the DC waveform can seriously influence the insulation performance of a GIL system.The waveshape can be a superposition of the DC and impulse waveform.In this study,the behavi...The presence of lightning impulses(LIs)on the DC waveform can seriously influence the insulation performance of a GIL system.The waveshape can be a superposition of the DC and impulse waveform.In this study,the behaviour of partial discharge(PD)on an epoxy surface is investigated under DC and LI superimposed voltage in SF6.The lightning impulses with different polarities are superimposed on the epoxy surface under both positive and negative DC voltages,respectively.Positive lightning impulses are superimposed on a negative DC voltage with a 90%of the partial discharge inception voltage(PDIV)magnitude.The number and amplitude of the PDs are used to evaluate the insulation performance.The experimental results show that the LI with a different polarity applied to DC can excite the PDs on the epoxy surface.The excitation effect of positive LI superimposed on negative DC is more significant.According to the impulse amplitude and PD characteristics,the influence of superimposed LI on PD excitation can be divided into three stages.As the superimposed LI increases,the amplitude of the excited PD increases gradually,while the PD number first increases and then decreases.This study is expected to provide reference for manufacture and protection of power equipment.展开更多
Background and aims:Laparoscopic hepatectomy is challenging,and ultrasound guidance is an effective aid but lacks standardization.This study aimed to evaluate a modified approach for laparoscopic ultrasonography to en...Background and aims:Laparoscopic hepatectomy is challenging,and ultrasound guidance is an effective aid but lacks standardization.This study aimed to evaluate a modified approach for laparoscopic ultrasonography to enhance surgical outcomes.Methods:Between January 2020 and August 2023,122 patients who underwent real-time ultrasound-guided laparoscopic anatomical hepatectomy for hepatocellular carcinoma were enrolled and divided into modified and traditional ultrasonography groups.The modified ultrasound application comprised intraoperative protocol-based laparoscopic ultrasonography comprising application scenarios;standardized positions for the surgeon,trocar,and probe;and the resulting standardized sections for various laparoscopic liver resections.Clinical characteristics and perioperative outcomes were compared between the two groups.Subgroup analysis was performed and comprised techniques for modified duct structure identification and portal vein branch puncture;both techniques were used in fluorescence probe-mounted laparoscopic liver resection using negative and positive staining procedures,respectively.Results:The traditional and modified groups comprised 64 and 58 patients,respectively.The patients’background characteristics were not significantly different between the groups.Surgical duration(283.4 min vs.225.1 min;p<0.001),Pringle maneuver duration(47.4 min vs.39.5 min;p?0.014),bleeding volume(258.6 mL vs.174.8 mL;p?0.005),overall complication rate(31.3%vs.15.5%;p?0.041),and postoperative stay were significantly greater in the traditional vs.modified ultrasonography groups,respectively.The modified method positively affected the number of punctures,success rate of staining,intraoperative bleeding volume,and operation duration.Conclusions:Modified ultrasonography improves the safety and effectiveness of laparoscopic hepatectomy.Ultrasonography is pivotal,especially in fluorescence probe-assisted laparoscopic liver resection.展开更多
基金financially supported by the National Natural Science Foundation of China(No.21276086)supported by the National Natural Science Foundation of China(No.21276086)
文摘The systematic research about the adsorption desulfurization and competitive behavior from 1-hexene over cesium-exchanged Y zeolites has been investigated. The structural properties of the adsorbents were characterized by X-ray diffraction（XRD）, N_2 sorption（BET） and thermal analysis（TGA）. The effects of calcination temperature, calcination atmosphere, and adsorption temperature were studied by the dynamic and static tests. The competitive adsorption mechanisms between thiophene and 1-hexene were studied by in-situ Fourier transform infrared spectroscopy（in-situ FTIR） and temperature-programmed desorption（TPD）. CsY adsorbents exhibited high selectivity for thiophene even when a large amount of olefins exist.In-situ FTIR spectra of thiophene and 1-hexene adsorption indicated that both thiophene and 1-hexene were mainly adsorbed on CsY via π-complexation. The higher desorption activated energy and higher adsorption heat of thiophene than 1-hexene obtained by thiophene-TPD and hexene-TPD has revealed that thiophene is adsorbed more strongly in CsY adsorbents than 1-hexene.
基金Project supported by the Doctoral Research Fund of Southwest University of Science and Technology(Grant No.20zx7104)the Sichuan Science and Technology Program(Grant No.2020ZYD055)the National Natural Science Foundation of China(Grant Nos.11905206 and 12075194)。
文摘Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2)C-M_(t)C composite ceramic was prepared by hot press sintering,with the Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2)C high-entropy carbide as the main phase.Secondary phase M_(x)C(M=Ti,Zr,Hf,Nb,Ta) was found to be distributed relatively uniform in the composite ceramic.The oxidation behavior of the ceramic was examined after exposure to 923 K and 1173 K.Morphology of the surface and cross sections of all oxidation samples were observed.The characteristics of the oxidation behavior of the high-entropy carbide and the secondary phase M_(x)C were compared and analyzed.The secondary phases(such as Ti-rich carbide or Hf-rich carbide) in the material were seriously oxidized at 923 K and 1173 K,which reflects the superior oxidation performance of the high-entropy carbide.The nano high-entropy oxides with Ti,Zr,Hf,Nb,Ta,and O elements were discovered by oxidation of the composite ceramic.This research will help deepen the understanding of the oxidation mechanism of high-entropy carbide and composite ceramic.
文摘The presence of lightning impulses(LIs)on the DC waveform can seriously influence the insulation performance of a GIL system.The waveshape can be a superposition of the DC and impulse waveform.In this study,the behaviour of partial discharge(PD)on an epoxy surface is investigated under DC and LI superimposed voltage in SF6.The lightning impulses with different polarities are superimposed on the epoxy surface under both positive and negative DC voltages,respectively.Positive lightning impulses are superimposed on a negative DC voltage with a 90%of the partial discharge inception voltage(PDIV)magnitude.The number and amplitude of the PDs are used to evaluate the insulation performance.The experimental results show that the LI with a different polarity applied to DC can excite the PDs on the epoxy surface.The excitation effect of positive LI superimposed on negative DC is more significant.According to the impulse amplitude and PD characteristics,the influence of superimposed LI on PD excitation can be divided into three stages.As the superimposed LI increases,the amplitude of the excited PD increases gradually,while the PD number first increases and then decreases.This study is expected to provide reference for manufacture and protection of power equipment.
基金supported by the National Natural Science Foundation of China(NSFC),with grants awarded to Xuan Meng(No.81972568)Hongguang Wang(No.82272963)the Natural Science Foundation of Beijing,with a grant awarded to Hongguang Wang(No.4222058).
文摘Background and aims:Laparoscopic hepatectomy is challenging,and ultrasound guidance is an effective aid but lacks standardization.This study aimed to evaluate a modified approach for laparoscopic ultrasonography to enhance surgical outcomes.Methods:Between January 2020 and August 2023,122 patients who underwent real-time ultrasound-guided laparoscopic anatomical hepatectomy for hepatocellular carcinoma were enrolled and divided into modified and traditional ultrasonography groups.The modified ultrasound application comprised intraoperative protocol-based laparoscopic ultrasonography comprising application scenarios;standardized positions for the surgeon,trocar,and probe;and the resulting standardized sections for various laparoscopic liver resections.Clinical characteristics and perioperative outcomes were compared between the two groups.Subgroup analysis was performed and comprised techniques for modified duct structure identification and portal vein branch puncture;both techniques were used in fluorescence probe-mounted laparoscopic liver resection using negative and positive staining procedures,respectively.Results:The traditional and modified groups comprised 64 and 58 patients,respectively.The patients’background characteristics were not significantly different between the groups.Surgical duration(283.4 min vs.225.1 min;p<0.001),Pringle maneuver duration(47.4 min vs.39.5 min;p?0.014),bleeding volume(258.6 mL vs.174.8 mL;p?0.005),overall complication rate(31.3%vs.15.5%;p?0.041),and postoperative stay were significantly greater in the traditional vs.modified ultrasonography groups,respectively.The modified method positively affected the number of punctures,success rate of staining,intraoperative bleeding volume,and operation duration.Conclusions:Modified ultrasonography improves the safety and effectiveness of laparoscopic hepatectomy.Ultrasonography is pivotal,especially in fluorescence probe-assisted laparoscopic liver resection.
