目的研究0.9%氯化钠溶液再通方法在肿瘤患者经外周置入中心静脉导管(peripherally inserted central catheter PICC)堵管中的应用效果。方法选择2016年1月至2017年12月PICC门诊维护的肿瘤带PICC患者发生完全堵管的病例45例作为对照组,...目的研究0.9%氯化钠溶液再通方法在肿瘤患者经外周置入中心静脉导管(peripherally inserted central catheter PICC)堵管中的应用效果。方法选择2016年1月至2017年12月PICC门诊维护的肿瘤带PICC患者发生完全堵管的病例45例作为对照组,采用以尿激酶为主配合三通接头负压反复抽吸和肝素封管两步的传统导管再通法。选择2018年1月至2019年12月PICC门诊维护的肿瘤带PICC患者发生完全堵管的病例46例作为观察组,采用以0.9%氯化钠溶液为主配合三通接头负压抽吸和尿激酶封管两步改良的导管再通法。通过历史对比法比较两种导管堵塞再通方法的临床效果。结果通方法的第一步“不同溶液配合三通接头负压抽吸法”,2组完全再通、部分再通比较差异无统计学意义(P=0.154)。对部分再通的导管采用第二部“封管保留法”,2组完全再通、导管未完全再通并拔管比较差异有统计学意义(P=0.046)。2组2种再通方法完全再通、未完全再通并拔管比较差异无统计学意义(P=0.985)。结论以0.9%氯化钠为主导管再通方法可以达到以尿激酶为主的再通一样的临床效果。改良的再通方法取材方便、经济、安全、有效,值得临床推广应用。展开更多
The reactions of cationic zirconium oxide clusters （ZrxOy^＋） with ethylene （C2H4） were investigated by using a time-of-flight mass spectrometer coupled with a laser ablation/supersonic expansion cluster source. S...The reactions of cationic zirconium oxide clusters （ZrxOy^＋） with ethylene （C2H4） were investigated by using a time-of-flight mass spectrometer coupled with a laser ablation/supersonic expansion cluster source. Some hydrogen containing products （ZrO2）xH^＋（x=-1-4） were observed after the reaction. The density functional theory calculations indicate that apart from the common oxygen transfer reaction channel, the hydrogen abstraction channel can also occur in （ZrO2）x^＋＋C2H4, which supports that the observed （ZrO2）xH^＋ may be due to （ZrO2）x^＋＋C2H4→（ZrO2）xH^＋＋C2H3. The rate constants of different reaction channels were also calculated by Rice-Rarnsberger-Kassel-Marcus theory.展开更多
Relative roles of Ekman transport and Ekman pumping in driving summer upwelling in the South China Sea （SCS） are examined using QuikSCAT scatterometer wind data. The major upwelling regions in the SCS are the coasta...Relative roles of Ekman transport and Ekman pumping in driving summer upwelling in the South China Sea （SCS） are examined using QuikSCAT scatterometer wind data. The major upwelling regions in the SCS are the coastal regions east and south- east of Vietnam （UESEV）, east and southeast of Hainan Island （UESEH）, and southeast of Guangdong province （USEG）. It is shown that the Ekman transport due to alongshore winds and Ekman pumping due to offshore wind stress curl play different roles in the three upwelling systems. In UESEV, Ekman pumping and Ekman transport are equally important in generating upwelling. The Ek- man transport increases linearly from 0.49 Sv in May to 1.23 Sv in August, while the Ekman pumping increases from 0.36 to 1.22 Sv during the same period. In UESEH, the mean estimates of Ekman transport and Ekman pumping are 0.14 and 0.07 Sv, respectively, indicating that 33% of the total wind-driven upwelling is due to Ekman pumping. In USEC~ the mean Ekman transport is 0.041 Sv with the peak occurring in July, while Ekman pumping is much smaller （0.003 on average）, indicating that the upwelling in this area is primarily driven by Ekman transport. In the summers of 2003 and 2007 following E1 Nifio-Southern Oscillation （ENSO） events, both Ekman transport and Ekman pumping decrease in UESEV due to the abnormally weak southwest monsoon. During the same events, however, Ekman transport is slightly enhanced and Ekman pumping is weakened in UESEH and USEG.展开更多
The Stokes spectrum in the stimulated Raman scattering (SRS) is very complicated. In this article, we use both Gaussian and Lorentz approximation to investigate the gain properties of multi pumping broadband Raman amp...The Stokes spectrum in the stimulated Raman scattering (SRS) is very complicated. In this article, we use both Gaussian and Lorentz approximation to investigate the gain properties of multi pumping broadband Raman amplifier, and present some schemes for flattening the gain. All the results show that the flatness of the gain spectrum is closely related to the pumping frequency grid. By researching the gain properties of Raman amplifiers of such ITU-T fibers as G.652, G.653, G.655 and large effective area non zero dispersion flattening fiber, we find that the Raman gain is associated with the fiber type and its transmission characteristics, especially it decreases with the increase of the effective core area.展开更多
Recently, Gao et al. [Opt. Commun. 283 （2010） 192] pointed out that Wang et al,＇s multiparty controlled quantum secure direct communication （CQSDC） protocol [Opt. Commun. 266 （2006） 732] has the information lea...Recently, Gao et al. [Opt. Commun. 283 （2010） 192] pointed out that Wang et al,＇s multiparty controlled quantum secure direct communication （CQSDC） protocol [Opt. Commun. 266 （2006） 732] has the information leakage problem and proposed an improved protocol. However, in the improved protocol, due to the introduction of an additional random sampling to avoid the weakness, the qubit efficiency is decreased. By introducing the base changing technique to the random sampling in Wang et al. ＇s protocol, this study overcomes the information leakage problem and provides a better qubit efficiency.展开更多
Variable speed pumped storage machines are used extensively in wind power plant and pumped storage power plant. This paper presents direct torque and flux control(DTFC) of a variable speed pumped storage power plant(V...Variable speed pumped storage machines are used extensively in wind power plant and pumped storage power plant. This paper presents direct torque and flux control(DTFC) of a variable speed pumped storage power plant(VSPSP). By this method both torque and flux have been applied to control the VSPSP. The comparison between VSPSP's control strategies is studied. At the first, a wind turbine with the capacity 2.2 k W and DTFC control strategies simulated then a 250 MW VSPSP is simulated with all of its parts(including electrical, mechanical, hydraulic and its control system) by MATLAB software. In all of simulations, both converters including two-level voltage source converter(2LVSC) and three-level voltage source converter(3LVSC) are applied. The results of applying 2LVSC and 3LVSC are the rapid dynamic responses with better efficiency, reducing the total harmonic distortion(THD) and ripple of rotor torque and flux.展开更多
Methane drainage is used in Polish coal mines in order to reduce mine methane emission as well as to keep methane concentration in mine workings at safe levels. This article describes the method of methane drainage us...Methane drainage is used in Polish coal mines in order to reduce mine methane emission as well as to keep methane concentration in mine workings at safe levels. This article describes the method of methane drainage used in longwall 2 in seam 506. In Poland, coal seams are frequently mined in difficult conditions of very high methane hazard. Under such situations, methane is drained by means of parallel ventilation headings. This paper shows the influence of a specific ventilation system on the drainage efficiency at longwall 2 in seam 506. At this longwall, measurements of methane emission and the efficiency of drained methane were conducted. They consisted in gauging methane concentration, air velocity, absolute air pressure and the amount of methane removed via a drainage system. Experimental data were used to estimate the variations in absolute methane-bearing capacity, ventilation air methane and most importantly, to gauge the efficiency of methane drainage.展开更多
文摘目的研究0.9%氯化钠溶液再通方法在肿瘤患者经外周置入中心静脉导管(peripherally inserted central catheter PICC)堵管中的应用效果。方法选择2016年1月至2017年12月PICC门诊维护的肿瘤带PICC患者发生完全堵管的病例45例作为对照组,采用以尿激酶为主配合三通接头负压反复抽吸和肝素封管两步的传统导管再通法。选择2018年1月至2019年12月PICC门诊维护的肿瘤带PICC患者发生完全堵管的病例46例作为观察组,采用以0.9%氯化钠溶液为主配合三通接头负压抽吸和尿激酶封管两步改良的导管再通法。通过历史对比法比较两种导管堵塞再通方法的临床效果。结果通方法的第一步“不同溶液配合三通接头负压抽吸法”,2组完全再通、部分再通比较差异无统计学意义(P=0.154)。对部分再通的导管采用第二部“封管保留法”,2组完全再通、导管未完全再通并拔管比较差异有统计学意义(P=0.046)。2组2种再通方法完全再通、未完全再通并拔管比较差异无统计学意义(P=0.985)。结论以0.9%氯化钠为主导管再通方法可以达到以尿激酶为主的再通一样的临床效果。改良的再通方法取材方便、经济、安全、有效,值得临床推广应用。
基金VI. ACKNOWLEDGEMENTS This work was supported by the Hundred Talents fund of The Chinese Academy of Sciences, the National Natural Science Foundation of China （No.20703048, No.20803083, and No.20933008）, the Center for Molecular Science Foundation of Institute of Chemistry, Chinese Academy of Sciences （No.CMS-CX200803）, and the National Basic Research Programs of China （No.2006CB932100 and No.2006CB806200）.
文摘The reactions of cationic zirconium oxide clusters （ZrxOy^＋） with ethylene （C2H4） were investigated by using a time-of-flight mass spectrometer coupled with a laser ablation/supersonic expansion cluster source. Some hydrogen containing products （ZrO2）xH^＋（x=-1-4） were observed after the reaction. The density functional theory calculations indicate that apart from the common oxygen transfer reaction channel, the hydrogen abstraction channel can also occur in （ZrO2）x^＋＋C2H4, which supports that the observed （ZrO2）xH^＋ may be due to （ZrO2）x^＋＋C2H4→（ZrO2）xH^＋＋C2H3. The rate constants of different reaction channels were also calculated by Rice-Rarnsberger-Kassel-Marcus theory.
基金the China Scholarship Council for sponsoring Dakui Wang’svisit to Horn Point Laboratory of University of Marylandthe National Nature Science Foundation of China(Grants Nos.41076011,40531006,41106024 and 40976014)the National Basic Research Program of China(Grant No.2011CB403600)
文摘Relative roles of Ekman transport and Ekman pumping in driving summer upwelling in the South China Sea （SCS） are examined using QuikSCAT scatterometer wind data. The major upwelling regions in the SCS are the coastal regions east and south- east of Vietnam （UESEV）, east and southeast of Hainan Island （UESEH）, and southeast of Guangdong province （USEG）. It is shown that the Ekman transport due to alongshore winds and Ekman pumping due to offshore wind stress curl play different roles in the three upwelling systems. In UESEV, Ekman pumping and Ekman transport are equally important in generating upwelling. The Ek- man transport increases linearly from 0.49 Sv in May to 1.23 Sv in August, while the Ekman pumping increases from 0.36 to 1.22 Sv during the same period. In UESEH, the mean estimates of Ekman transport and Ekman pumping are 0.14 and 0.07 Sv, respectively, indicating that 33% of the total wind-driven upwelling is due to Ekman pumping. In USEC~ the mean Ekman transport is 0.041 Sv with the peak occurring in July, while Ekman pumping is much smaller （0.003 on average）, indicating that the upwelling in this area is primarily driven by Ekman transport. In the summers of 2003 and 2007 following E1 Nifio-Southern Oscillation （ENSO） events, both Ekman transport and Ekman pumping decrease in UESEV due to the abnormally weak southwest monsoon. During the same events, however, Ekman transport is slightly enhanced and Ekman pumping is weakened in UESEH and USEG.
文摘The Stokes spectrum in the stimulated Raman scattering (SRS) is very complicated. In this article, we use both Gaussian and Lorentz approximation to investigate the gain properties of multi pumping broadband Raman amplifier, and present some schemes for flattening the gain. All the results show that the flatness of the gain spectrum is closely related to the pumping frequency grid. By researching the gain properties of Raman amplifiers of such ITU-T fibers as G.652, G.653, G.655 and large effective area non zero dispersion flattening fiber, we find that the Raman gain is associated with the fiber type and its transmission characteristics, especially it decreases with the increase of the effective core area.
文摘Recently, Gao et al. [Opt. Commun. 283 （2010） 192] pointed out that Wang et al,＇s multiparty controlled quantum secure direct communication （CQSDC） protocol [Opt. Commun. 266 （2006） 732] has the information leakage problem and proposed an improved protocol. However, in the improved protocol, due to the introduction of an additional random sampling to avoid the weakness, the qubit efficiency is decreased. By introducing the base changing technique to the random sampling in Wang et al. ＇s protocol, this study overcomes the information leakage problem and provides a better qubit efficiency.
基金the output of a research project (Title: Application of Doubly Fed Asynchronous machine in Pumped Storage Hydropower Plant in Generate Mode, supported by Islamic Azad University South Tehran Branch)
文摘Variable speed pumped storage machines are used extensively in wind power plant and pumped storage power plant. This paper presents direct torque and flux control(DTFC) of a variable speed pumped storage power plant(VSPSP). By this method both torque and flux have been applied to control the VSPSP. The comparison between VSPSP's control strategies is studied. At the first, a wind turbine with the capacity 2.2 k W and DTFC control strategies simulated then a 250 MW VSPSP is simulated with all of its parts(including electrical, mechanical, hydraulic and its control system) by MATLAB software. In all of simulations, both converters including two-level voltage source converter(2LVSC) and three-level voltage source converter(3LVSC) are applied. The results of applying 2LVSC and 3LVSC are the rapid dynamic responses with better efficiency, reducing the total harmonic distortion(THD) and ripple of rotor torque and flux.
文摘Methane drainage is used in Polish coal mines in order to reduce mine methane emission as well as to keep methane concentration in mine workings at safe levels. This article describes the method of methane drainage used in longwall 2 in seam 506. In Poland, coal seams are frequently mined in difficult conditions of very high methane hazard. Under such situations, methane is drained by means of parallel ventilation headings. This paper shows the influence of a specific ventilation system on the drainage efficiency at longwall 2 in seam 506. At this longwall, measurements of methane emission and the efficiency of drained methane were conducted. They consisted in gauging methane concentration, air velocity, absolute air pressure and the amount of methane removed via a drainage system. Experimental data were used to estimate the variations in absolute methane-bearing capacity, ventilation air methane and most importantly, to gauge the efficiency of methane drainage.
