The fragmentation patterns of anhydro sugars 1—6 in electron impact mass spectrometry have been proposed, and verified by means of metastable ions scanning method.
The electron impact ionization mass spectral fragmentations of a series of acylaminotetraoxyphosphoranes were investigated. The results showed that EIMS of such compounds exhibited very characteristic fragmentation pa...The electron impact ionization mass spectral fragmentations of a series of acylaminotetraoxyphosphoranes were investigated. The results showed that EIMS of such compounds exhibited very characteristic fragmentation patterns, which would provide useful clues for the structural assignment of this type of compounds.展开更多
Currently the mass media possess a great deal of influences in society and politics.The mass media have a powerful influence on politics.This paper will mainly analyze the impacts of mass media on three aspects of pol...Currently the mass media possess a great deal of influences in society and politics.The mass media have a powerful influence on politics.This paper will mainly analyze the impacts of mass media on three aspects of political life and behaviors in Britain.展开更多
Electron impact ionization mass spectra of six new synthetic bis-piperazinium salts (M2+ 2Br-2HC1) with anti-tumor activities were obtained. Although the M+ ions and double charge ions M2+ were notobserved in E1 mass ...Electron impact ionization mass spectra of six new synthetic bis-piperazinium salts (M2+ 2Br-2HC1) with anti-tumor activities were obtained. Although the M+ ions and double charge ions M2+ were notobserved in E1 mass spectra, some strange ions such as [M-2]+ ions,[M-R]+ ions , [M-R-l]+ ions, [M-2R]+ ions and even [RX]+ ions presented in EIMS by decreasing the electron energy. These phenomena may be explained as R+ rearrangement and intermolecular reaction occurring in the condensed phase. We tried to describe the main routes of fragmentation and high sensitive mass spectra of the fragments oaboutthese compounds.展开更多
Impact-induced damage to jointed rock masses has important consequences in various mining and civil engineering applications. This paper reports a numerical investigation to address the responses of jointed rock masse...Impact-induced damage to jointed rock masses has important consequences in various mining and civil engineering applications. This paper reports a numerical investigation to address the responses of jointed rock masses subjected to impact loading. It also focuses on the static and dynamic properties of an intact rock derived from a series of laboratory tests on meta-sandstone samples from a quarry in Nova Scotia, Canada. A distinct element code(PFC2D) was used to generate a bonded particle model(BPM) to simulate both the static and dynamic properties of the intact rock. The calibrated BPM was then used to construct large-scale jointed rock mass samples by incorporating discrete joint networks of multiple joint intensities into the intact rock matrix represented by the BPM. Finally, the impact-induced damage inflicted by a rigid projectile particle on the jointed rock mass samples was determined through the use of the numerical model. The simulation results show that joints play an important role in the impactinduced rock mass damage where higher joint intensity results in more damage to the rock mass. This is mainly attributed to variations of stress wave propagation in jointed rock masses as compared to intact rock devoid of joints.展开更多
This study focuses on the effect of lateral mass impact on ring-stiffened thin-walled cylindrical shell.Cylindrical shells were fabricated to validate the numerical modeling and analytical techniques,and drop tests we...This study focuses on the effect of lateral mass impact on ring-stiffened thin-walled cylindrical shell.Cylindrical shells were fabricated to validate the numerical modeling and analytical techniques,and drop tests were performed using a rigid spherical indenter.Next,stiffened-ring cylindrical shells with various structural size parameters were simulated using ABAQUS software.The relationships between the impact force,deformation displacement,and rebound velocity were established,on the basis of impact mechanics theory and simulation results.It derived fitting functions to analyse the relationship between the maximum load and maximum displacement of ring-stiffened cylindrical shell under dynamic mass impact.Based on the validation of the simulation model,the fitting function data were compared with the simulation results,and the functions showed a good accuracy.Besides,the parameters,mass ratio and stiffened-ring mass ratio were used to reflect the effect of the mass change in the ring-stiffened cylindrical shell.Furthermore,parametric studies on ring-stiffened cylindrical shell models were conducted to analyse the progressive impact responses.展开更多
The mass spectrometric fragmentation of 1-（benzyloxycarbonyl）amino-2-alkyl/cycloalkyl thioacetates has been studied with the aid of mass-analysed ion kinetic energy spectrometry under electron impact ionization. All...The mass spectrometric fragmentation of 1-（benzyloxycarbonyl）amino-2-alkyl/cycloalkyl thioacetates has been studied with the aid of mass-analysed ion kinetic energy spectrometry under electron impact ionization. All compounds show a tendency to eliminate a ketene, thioacetic acid, and benzyl carbamate molecule, or an acetyl and benzyloxy radicals. A thioester pyrolysis-type rearrangement under electron impact ionizations was observed.展开更多
During the excavation of deep coal and rock mass, the radial stress of the free face changes from three-dimensional compression state to two-dimensional stress, bearing the combined action of dynamic disturbance and s...During the excavation of deep coal and rock mass, the radial stress of the free face changes from three-dimensional compression state to two-dimensional stress, bearing the combined action of dynamic disturbance and static load at the same time. With that, many mines suffer from dynamic disasters, such as coal and gas outburst, rock burst and rock caving during deep mining excavation, which is often accompanied by plate crack, spalling and other disasters, seriously affecting the stability of stope and roadway. Taking thin rectangular coal and rock mass as the research object, the dual equation of the free vibration was derived and the exact solution model of the free vibration was established with the use of Hamilton dual system. Based on the action characteristics of the uniform impact load, the effective mode of the forced vibration was obtained by using the Duhamel integral principle and the orthogonality of the mode function. Based on the third strength theory and the numerical simulation results, the dynamic damage process and development trend of coal and rock mass were analyzed under uniform impact load. It was concluded that the starting position of dynamic damage can be judged by the first order main mode, and the development direction and trend of the damage can be judged by the fifth and sixth order main modes. It was concluded that the vibration mode functions of coal and rock mass with four side fixed (C-C-C-C), the two sides fixed and simply supported on the other (S-C-S-C) are mainly composed of three modes that are the first order (dominant frequency), the fifth order and the sixth order, from which the dynamic damage mechanism is preliminarily studied.展开更多
AIM: To investigate possible disparities in perioperative morbidity and mortality among different body mass index(BMI) groups and to simulate the impact that these differences might have had on the cohort of patients ...AIM: To investigate possible disparities in perioperative morbidity and mortality among different body mass index(BMI) groups and to simulate the impact that these differences might have had on the cohort of patients undergoing cadaveric liver transplantation(LT).METHODS: All adult recipients undergoing first time LT for benign conditions and receiving a whole graft from brain-dead donors were selected from the united network of organ sharing registry. From January 1994 to June 2013, 48281 patients satisfied the inclusion criteria and were stratified by their BMI. The hypothesis that abnormal BMIs were independent predictors of inferior outcomes was tested with univariate and multivariate regression analyses.RESULTS: In comparison to normal weight recipients, underweight and morbidly obese recipients had increased 90-d mortality(adjusted OR = 1.737; 95%CI: 1.185-2.548, P = 0.005)(adjusted OR = 1.956; 95%CI: 1.473-2.597, P = 0.000) respectively and inferior patients' survivals(adjusted HR = 1.265; 95%CI: 1.096-1.461, P = 0.000)(adjusted HR = 1.157; 95%CI: 1.031-1.299, P = 0.013) respectively. Overall, patients' 5-year survival were 73.9% for normal-weight, 71.1% for underweight, 74.0% for overweight, 74.4% for class Ⅰ obese, 75.0% for class Ⅱ obese and 71.5% for class Ⅲ obese recipients. Analysis of hypothetical exclusion of underweight and morbidly obese patients from the pool of potential LT candidates would have improved the overall survival of the entire cohort by2.7%(95%CI: 2.5%-3.6%).CONCLUSION: Selected morbidly obese patients undergoing LT for benign conditions had 5-year survival rates clinically comparable to normal weight recipients. Impact analysis showed that exclusion of high-risk recipients(underweight and morbid obese patients) would not significantly improve the overall survival of the entire cohort of patients requiring LT.展开更多
Exclusive intermediate mass fragments（IMFs）are measured at forward angles forthe <sup>40</sup>Ar+<sup>nal</sup>Ag reaction at 30 MeV/u.The impact parameter is determined using the totaltransv...Exclusive intermediate mass fragments（IMFs）are measured at forward angles forthe <sup>40</sup>Ar+<sup>nal</sup>Ag reaction at 30 MeV/u.The impact parameter is determined using the totaltransverse momentum method and linear momentum transfer method.IMFs emitted at forwardangles mainly come from projectile fragmentation in peripheral collisions,while IMFs in centralcollision mainly come from decay of hot target-like sources.IMFs from both projectile-like andtarget-like sources are observed in mid-central collision.In addition,the third component,non-equilibrium mid-rapidity components are observed in central,mid-central and peripheralcollisions.展开更多
在以往惯质调谐质量阻尼器(tuned mass damper-inerter, TMDI)的研究基础上,引入非线性碰撞机制,提出一种带碰撞的新型惯质调谐质量阻尼器(pounding tuned mass damper-inerter, PTMDI)来对斜拉索的涡激振动进行控制。该阻尼器不仅能减...在以往惯质调谐质量阻尼器(tuned mass damper-inerter, TMDI)的研究基础上,引入非线性碰撞机制,提出一种带碰撞的新型惯质调谐质量阻尼器(pounding tuned mass damper-inerter, PTMDI)来对斜拉索的涡激振动进行控制。该阻尼器不仅能减小装置尺寸,又能利用振子在碰撞过程中产生的加速度突变来提高惯质器的质量放大效应,在一定程度上解决传统惯质型阻尼器一端尽量固接的安装方式,布置上更为灵活。建立了设有该装置的斜拉索涡激减振控制方程,分析了拉索涡激振动特性,并对其减振性能进行了研究。对阻尼器惯容参数和碰撞参数的影响及优化问题进行了探讨,给出了最优参数的取值方法。算例表明,所提PTMDI能显著降低斜拉索的涡激振动响应,且在所提优化方法得到的最优参数下具有更为优越的控制能力。对于常遇风时拉索出现的多模态涡激振动控制分析表明,碰撞机制能使PTMDI的鲁棒性得到提升,对多模态涡激振动也有相当程度的控制效果。展开更多
文摘The fragmentation patterns of anhydro sugars 1—6 in electron impact mass spectrometry have been proposed, and verified by means of metastable ions scanning method.
文摘The electron impact ionization mass spectral fragmentations of a series of acylaminotetraoxyphosphoranes were investigated. The results showed that EIMS of such compounds exhibited very characteristic fragmentation patterns, which would provide useful clues for the structural assignment of this type of compounds.
文摘Currently the mass media possess a great deal of influences in society and politics.The mass media have a powerful influence on politics.This paper will mainly analyze the impacts of mass media on three aspects of political life and behaviors in Britain.
文摘Electron impact ionization mass spectra of six new synthetic bis-piperazinium salts (M2+ 2Br-2HC1) with anti-tumor activities were obtained. Although the M+ ions and double charge ions M2+ were notobserved in E1 mass spectra, some strange ions such as [M-2]+ ions,[M-R]+ ions , [M-R-l]+ ions, [M-2R]+ ions and even [RX]+ ions presented in EIMS by decreasing the electron energy. These phenomena may be explained as R+ rearrangement and intermolecular reaction occurring in the condensed phase. We tried to describe the main routes of fragmentation and high sensitive mass spectra of the fragments oaboutthese compounds.
基金the financial support provided by Natural Science and Engineering Research Council of Canada (NSERC) Grant No: RGPIN-2014-03992
文摘Impact-induced damage to jointed rock masses has important consequences in various mining and civil engineering applications. This paper reports a numerical investigation to address the responses of jointed rock masses subjected to impact loading. It also focuses on the static and dynamic properties of an intact rock derived from a series of laboratory tests on meta-sandstone samples from a quarry in Nova Scotia, Canada. A distinct element code(PFC2D) was used to generate a bonded particle model(BPM) to simulate both the static and dynamic properties of the intact rock. The calibrated BPM was then used to construct large-scale jointed rock mass samples by incorporating discrete joint networks of multiple joint intensities into the intact rock matrix represented by the BPM. Finally, the impact-induced damage inflicted by a rigid projectile particle on the jointed rock mass samples was determined through the use of the numerical model. The simulation results show that joints play an important role in the impactinduced rock mass damage where higher joint intensity results in more damage to the rock mass. This is mainly attributed to variations of stress wave propagation in jointed rock masses as compared to intact rock devoid of joints.
基金supported by the National Natural Science Foundation of China(Grant No.51508123,named“Study on blast response of floating roof storage tank in material point method”)Natural Science Foundation of Heilongjiang Province,China(LH2019A008)to provide fund for conducting experiments and research.The authors would like to acknowledge Professor Wei Wang in Harbin Institute of Technology for instructions and help in experiment design.
文摘This study focuses on the effect of lateral mass impact on ring-stiffened thin-walled cylindrical shell.Cylindrical shells were fabricated to validate the numerical modeling and analytical techniques,and drop tests were performed using a rigid spherical indenter.Next,stiffened-ring cylindrical shells with various structural size parameters were simulated using ABAQUS software.The relationships between the impact force,deformation displacement,and rebound velocity were established,on the basis of impact mechanics theory and simulation results.It derived fitting functions to analyse the relationship between the maximum load and maximum displacement of ring-stiffened cylindrical shell under dynamic mass impact.Based on the validation of the simulation model,the fitting function data were compared with the simulation results,and the functions showed a good accuracy.Besides,the parameters,mass ratio and stiffened-ring mass ratio were used to reflect the effect of the mass change in the ring-stiffened cylindrical shell.Furthermore,parametric studies on ring-stiffened cylindrical shell models were conducted to analyse the progressive impact responses.
文摘The mass spectrometric fragmentation of 1-（benzyloxycarbonyl）amino-2-alkyl/cycloalkyl thioacetates has been studied with the aid of mass-analysed ion kinetic energy spectrometry under electron impact ionization. All compounds show a tendency to eliminate a ketene, thioacetic acid, and benzyl carbamate molecule, or an acetyl and benzyloxy radicals. A thioester pyrolysis-type rearrangement under electron impact ionizations was observed.
文摘During the excavation of deep coal and rock mass, the radial stress of the free face changes from three-dimensional compression state to two-dimensional stress, bearing the combined action of dynamic disturbance and static load at the same time. With that, many mines suffer from dynamic disasters, such as coal and gas outburst, rock burst and rock caving during deep mining excavation, which is often accompanied by plate crack, spalling and other disasters, seriously affecting the stability of stope and roadway. Taking thin rectangular coal and rock mass as the research object, the dual equation of the free vibration was derived and the exact solution model of the free vibration was established with the use of Hamilton dual system. Based on the action characteristics of the uniform impact load, the effective mode of the forced vibration was obtained by using the Duhamel integral principle and the orthogonality of the mode function. Based on the third strength theory and the numerical simulation results, the dynamic damage process and development trend of coal and rock mass were analyzed under uniform impact load. It was concluded that the starting position of dynamic damage can be judged by the first order main mode, and the development direction and trend of the damage can be judged by the fifth and sixth order main modes. It was concluded that the vibration mode functions of coal and rock mass with four side fixed (C-C-C-C), the two sides fixed and simply supported on the other (S-C-S-C) are mainly composed of three modes that are the first order (dominant frequency), the fifth order and the sixth order, from which the dynamic damage mechanism is preliminarily studied.
文摘AIM: To investigate possible disparities in perioperative morbidity and mortality among different body mass index(BMI) groups and to simulate the impact that these differences might have had on the cohort of patients undergoing cadaveric liver transplantation(LT).METHODS: All adult recipients undergoing first time LT for benign conditions and receiving a whole graft from brain-dead donors were selected from the united network of organ sharing registry. From January 1994 to June 2013, 48281 patients satisfied the inclusion criteria and were stratified by their BMI. The hypothesis that abnormal BMIs were independent predictors of inferior outcomes was tested with univariate and multivariate regression analyses.RESULTS: In comparison to normal weight recipients, underweight and morbidly obese recipients had increased 90-d mortality(adjusted OR = 1.737; 95%CI: 1.185-2.548, P = 0.005)(adjusted OR = 1.956; 95%CI: 1.473-2.597, P = 0.000) respectively and inferior patients' survivals(adjusted HR = 1.265; 95%CI: 1.096-1.461, P = 0.000)(adjusted HR = 1.157; 95%CI: 1.031-1.299, P = 0.013) respectively. Overall, patients' 5-year survival were 73.9% for normal-weight, 71.1% for underweight, 74.0% for overweight, 74.4% for class Ⅰ obese, 75.0% for class Ⅱ obese and 71.5% for class Ⅲ obese recipients. Analysis of hypothetical exclusion of underweight and morbidly obese patients from the pool of potential LT candidates would have improved the overall survival of the entire cohort by2.7%(95%CI: 2.5%-3.6%).CONCLUSION: Selected morbidly obese patients undergoing LT for benign conditions had 5-year survival rates clinically comparable to normal weight recipients. Impact analysis showed that exclusion of high-risk recipients(underweight and morbid obese patients) would not significantly improve the overall survival of the entire cohort of patients requiring LT.
基金The Project supported by National Natural Science Foundation of China
文摘Exclusive intermediate mass fragments（IMFs）are measured at forward angles forthe <sup>40</sup>Ar+<sup>nal</sup>Ag reaction at 30 MeV/u.The impact parameter is determined using the totaltransverse momentum method and linear momentum transfer method.IMFs emitted at forwardangles mainly come from projectile fragmentation in peripheral collisions,while IMFs in centralcollision mainly come from decay of hot target-like sources.IMFs from both projectile-like andtarget-like sources are observed in mid-central collision.In addition,the third component,non-equilibrium mid-rapidity components are observed in central,mid-central and peripheralcollisions.
文摘在以往惯质调谐质量阻尼器(tuned mass damper-inerter, TMDI)的研究基础上,引入非线性碰撞机制,提出一种带碰撞的新型惯质调谐质量阻尼器(pounding tuned mass damper-inerter, PTMDI)来对斜拉索的涡激振动进行控制。该阻尼器不仅能减小装置尺寸,又能利用振子在碰撞过程中产生的加速度突变来提高惯质器的质量放大效应,在一定程度上解决传统惯质型阻尼器一端尽量固接的安装方式,布置上更为灵活。建立了设有该装置的斜拉索涡激减振控制方程,分析了拉索涡激振动特性,并对其减振性能进行了研究。对阻尼器惯容参数和碰撞参数的影响及优化问题进行了探讨,给出了最优参数的取值方法。算例表明,所提PTMDI能显著降低斜拉索的涡激振动响应,且在所提优化方法得到的最优参数下具有更为优越的控制能力。对于常遇风时拉索出现的多模态涡激振动控制分析表明,碰撞机制能使PTMDI的鲁棒性得到提升,对多模态涡激振动也有相当程度的控制效果。
