The absorption effect of actual subsurface media can weaken wavefield energy, decrease the dominating frequency, and further lead to reduced resolution. In migration, some actions can be taken to compensate for the ab...The absorption effect of actual subsurface media can weaken wavefield energy, decrease the dominating frequency, and further lead to reduced resolution. In migration, some actions can be taken to compensate for the absorption effect and enhance the resolution. In this paper, we derive a one-way wave equation with an attenuation term based on the time- space domain high angle one-way wave equation. A complicated geological model is then designed and synthetic shot gathers are simulated with acoustic wave equations without and with an absorbing term. The derived one-way wave equation is applied to the migration of the synthetic gathers without and with attenuation compensation for the simulated shot gathers. Three migration profiles are obtained. The first and second profiles are from the shot gathers without and with attenuation using the migration method without compensation, the third one is from the shot gathers with attenuation using the migration method with compensation. The first and third profiles are almost the same, and the second profile is different from the others below the absorptive layers. The amplitudes of the interfaces below the absorptive layers are weak because of their absorption. This method is also applied to field data. It is concluded from the migration examples that the migration method discussed in this paper is feasible.展开更多
Objectives: To monitor the prevalence and riskfactors of HIV in high-risk populations, to provide ascientific basis for policy-makers to evaluate theeffectiveness of HIV prevention, and to formulate stra-tegic measure...Objectives: To monitor the prevalence and riskfactors of HIV in high-risk populations, to provide ascientific basis for policy-makers to evaluate theeffectiveness of HIV prevention, and to formulate stra-tegic measures for prevention and treatment.Methods: From 1997 to 2002, 3 110 incarceratedcommercial sex workers (CSWs) and 4 748 outpatientsof a sexually-transmitted disease (STD) departmentunderwent HIV antibody testing in Shenzhen. HIVantibody screening of samples was made by enzymelinked immunosorbent assay (ELISA).Results: Among the outpatients, the proportiondiagnosed with an STD were 71.5%, 70%, 87.5%,87.3%, 85.2%, 82.2%, respectively, in the years from1997 to 2002. The predominant STDs presented weresyphilis, non-gonococcal urethritis (NGU) and condy-loma acuminata (CA). One out-patient was found to beHIV-positive in 2001 and another in 2002, with a preva-lence of 0.25 % (1/400). During the same period, theproportion of CSW who reported always using a con-dom were 45.9%, 49.8%, 40.8%, 57.9%, 44.9%,and 58.2%. 13.4% of CSW were drug users, amongwhom 9.3% used injection drugs and 3.2% reportedsharing syringes with others. One CSW was found tobe HIV-positive in the first survey in 1998 with a preva-lence of 0.4 % (1/250). In 2002, two CSW tested posi-tive in the first semiannual study with a prevalence of0.65% (2/307), and one case in the second study, witha prevalence of 0.48% (1/210).Conclusion: The result of this surveillance indicatethat HIV is prevalent among these high-risk popula-tions of commercial sex workers and STD outpatients.展开更多
A novel silica-supported tert-butyl 2-picolyamino-N-acetate chelating resin (Si-AMPY-1) was successfully synthesized and characterized by elemental analysis, FT-IR, SEM and 13 C CP/MAS NMR. The adsorption behaviors of...A novel silica-supported tert-butyl 2-picolyamino-N-acetate chelating resin (Si-AMPY-1) was successfully synthesized and characterized by elemental analysis, FT-IR, SEM and 13 C CP/MAS NMR. The adsorption behaviors of the Si-AMPY-1 resin for Cu(Ⅱ) and Ni(Ⅱ) were studied with batch and column methods. The batch experiments indicated that the Si-AMPY-1 resin adsorbed Ni(Ⅱ) mainly via physisorption, while adsorbed Cu(II) via chemisorption. The column dynamic breakthrough curves revealed thatthe Si-AMPY-1 resin can efficiently separate Cu(Ⅱ) from the simulated nickel electrolyte before the breakthrough point. Moreover, the concentration of Cu(Ⅱ) in the column effluent was decreased to be less than 3 mg/L within the first 43 BV (bed volumes), and the mass ratio of Cu/Ni was 21:1 in the saturated resin, which completely satisfied the industrial requirements of the nickel electrorefining process. Therefore, it was concluded that the Si-AMPY-1 resin can be a promising candidate for the deep removal of Cu(Ⅱ) from the nickel electrolyte.展开更多
Objective To evaluate effect of Neurokinin receptor antagonist on the prevention from hyper-pnea-induced bronchoconstriction using a dual Neurokinin receptor antagonist FK224. Methods 12 pathogen-free Hartley guinea p...Objective To evaluate effect of Neurokinin receptor antagonist on the prevention from hyper-pnea-induced bronchoconstriction using a dual Neurokinin receptor antagonist FK224. Methods 12 pathogen-free Hartley guinea pigs were divided into two groups randomly-. Dimethyl sulfoxide (DMSO) control group (n =6)and FK224 group (n =6). Guinea pigs were anesthetized with pentobarbital sodium. A cervical tracheostomy wasperformed and a polyethylene tube was inserted into the trachea. After measuring baseline value of the lung resist-ance (RL) and dynamic compliance of respiratory system (Cdyn), DMSO (0.3 ml/kg) and FK224 (1mg/kg) wereadministered by injection through jugular vein respectively. A rodent respirator with dry 5% CO2-95% O2 mixture atroom temperature provided mechanical ventilation ( VT 8ml/animal, 100breaths/min) for 5min. RL and Cdyn of 2groups were measured after isocapnic hyperpnea challenge. Results In DMSO control group, isocapnic hyper-pnea of dry gas elicited a marked increase in RL and decrease in Cdyn. RL and Cdyn of FK224 group did not changesignificantly. Conclusion FK224 can inhibit the increase in RL and decrease in Cdyn caused by isocapnic hy-perpnea in guinea pigs. And antagonists of tachykinins receptors might have effect on prophylaxis and treatment inexercise-induced asthma.展开更多
The Shenbei mining area in China contains typical soft rock from the Tertiary Period. As mining depths increase, deep soft rock roadways are damaged by large deformations and constantly need to be repaired to meet saf...The Shenbei mining area in China contains typical soft rock from the Tertiary Period. As mining depths increase, deep soft rock roadways are damaged by large deformations and constantly need to be repaired to meet safety requirements, which is a great security risk. In this study, the characteristics of deformation and failure of typical roadway were analyzed, and the fundamental reason for the roadway deformation was that traditional support methods and materials cannot control the large deformation of deep soft rock. Deep soft rock support technology was developed based on constant resistance energy absorption using constant resistance large deformation bolts. The correlative deformation mechanisms of surrounding rock and bolt were analyzed to understand the principle of constant resistance energy absorption. The new technology works well on-site and provides a new method for the excavation of roadwavs in Tertiary deed soft rock.展开更多
In order to further reduce the sulfur content in liquid hydrocarbon fuels,a desulfurization process by adsorption for removing alkyl dibenzothiophenes was investigated.Desulfurization of model gasoline by bentonite ad...In order to further reduce the sulfur content in liquid hydrocarbon fuels,a desulfurization process by adsorption for removing alkyl dibenzothiophenes was investigated.Desulfurization of model gasoline by bentonite adsorbents loaded with silver nitrate was studied.The test results indicated that the bentonite adsorbents loaded with Ag + ions were effective for adsorbing the alkyl dibenzothiophenes.The crystal structure of bentonite adsorbents was characterized by X-ray diffraction (XRD) and their acidity was measured by Fourier transform infrared (FT-IR) spectroscopy.Several factors influencing the desulfurization capability,including the Ag + loading,the baking temperature,as well as the reaction temperature,were investigated.The desulfurization efficiency was enhanced by increasing the Ag + loading and the best result was obtained at a silver loading of 7 m%.It was found that the adsorption capacity of the alkyl dibenzothiophenes on bentonite loaded with Ag + ions increased with a decreasing temperature.Baking of the adsorbent could also improve the desulfurization capacity,and the optimum baking temperature was 423 K.展开更多
The absorption process of radiative heat in its transmission medium and the effect of ultra-attenuation on the radiative characteristics are analyzed in detail. A method of ultra-attenuation to enhance the radiative c...The absorption process of radiative heat in its transmission medium and the effect of ultra-attenuation on the radiative characteristics are analyzed in detail. A method of ultra-attenuation to enhance the radiative characteristics of the medium is proposed. It is proved that decreasing the particle size of coatings can increase the transmission depth of radiative heat and get higher emissivity and absorptivity both theoretically and practically. Ultra-attenuation and nanocrystallization will bring a brilliant prospect to the development of radiative coatings.展开更多
基金supported in part by the National Natural Science Foundation of China(No.40974069,41174119)the Research of Novel Method and Technology of Geophysical Prospecting,CNPC(No.2011A-3602)the National Major Science and Technology Program(No.2011ZX05010,2011ZX05024)
文摘The absorption effect of actual subsurface media can weaken wavefield energy, decrease the dominating frequency, and further lead to reduced resolution. In migration, some actions can be taken to compensate for the absorption effect and enhance the resolution. In this paper, we derive a one-way wave equation with an attenuation term based on the time- space domain high angle one-way wave equation. A complicated geological model is then designed and synthetic shot gathers are simulated with acoustic wave equations without and with an absorbing term. The derived one-way wave equation is applied to the migration of the synthetic gathers without and with attenuation compensation for the simulated shot gathers. Three migration profiles are obtained. The first and second profiles are from the shot gathers without and with attenuation using the migration method without compensation, the third one is from the shot gathers with attenuation using the migration method with compensation. The first and third profiles are almost the same, and the second profile is different from the others below the absorptive layers. The amplitudes of the interfaces below the absorptive layers are weak because of their absorption. This method is also applied to field data. It is concluded from the migration examples that the migration method discussed in this paper is feasible.
文摘Objectives: To monitor the prevalence and riskfactors of HIV in high-risk populations, to provide ascientific basis for policy-makers to evaluate theeffectiveness of HIV prevention, and to formulate stra-tegic measures for prevention and treatment.Methods: From 1997 to 2002, 3 110 incarceratedcommercial sex workers (CSWs) and 4 748 outpatientsof a sexually-transmitted disease (STD) departmentunderwent HIV antibody testing in Shenzhen. HIVantibody screening of samples was made by enzymelinked immunosorbent assay (ELISA).Results: Among the outpatients, the proportiondiagnosed with an STD were 71.5%, 70%, 87.5%,87.3%, 85.2%, 82.2%, respectively, in the years from1997 to 2002. The predominant STDs presented weresyphilis, non-gonococcal urethritis (NGU) and condy-loma acuminata (CA). One out-patient was found to beHIV-positive in 2001 and another in 2002, with a preva-lence of 0.25 % (1/400). During the same period, theproportion of CSW who reported always using a con-dom were 45.9%, 49.8%, 40.8%, 57.9%, 44.9%,and 58.2%. 13.4% of CSW were drug users, amongwhom 9.3% used injection drugs and 3.2% reportedsharing syringes with others. One CSW was found tobe HIV-positive in the first survey in 1998 with a preva-lence of 0.4 % (1/250). In 2002, two CSW tested posi-tive in the first semiannual study with a prevalence of0.65% (2/307), and one case in the second study, witha prevalence of 0.48% (1/210).Conclusion: The result of this surveillance indicatethat HIV is prevalent among these high-risk popula-tions of commercial sex workers and STD outpatients.
基金Project (2014CB643401) supported by the National Basic Research Program of ChinaProjects (51134007,51474256) supported by the National Natural Science Foundation of ChinaProject (2016TP1007) supported by the Hunan Provincial Science and Technology Plan Project in China
文摘A novel silica-supported tert-butyl 2-picolyamino-N-acetate chelating resin (Si-AMPY-1) was successfully synthesized and characterized by elemental analysis, FT-IR, SEM and 13 C CP/MAS NMR. The adsorption behaviors of the Si-AMPY-1 resin for Cu(Ⅱ) and Ni(Ⅱ) were studied with batch and column methods. The batch experiments indicated that the Si-AMPY-1 resin adsorbed Ni(Ⅱ) mainly via physisorption, while adsorbed Cu(II) via chemisorption. The column dynamic breakthrough curves revealed thatthe Si-AMPY-1 resin can efficiently separate Cu(Ⅱ) from the simulated nickel electrolyte before the breakthrough point. Moreover, the concentration of Cu(Ⅱ) in the column effluent was decreased to be less than 3 mg/L within the first 43 BV (bed volumes), and the mass ratio of Cu/Ni was 21:1 in the saturated resin, which completely satisfied the industrial requirements of the nickel electrorefining process. Therefore, it was concluded that the Si-AMPY-1 resin can be a promising candidate for the deep removal of Cu(Ⅱ) from the nickel electrolyte.
文摘Objective To evaluate effect of Neurokinin receptor antagonist on the prevention from hyper-pnea-induced bronchoconstriction using a dual Neurokinin receptor antagonist FK224. Methods 12 pathogen-free Hartley guinea pigs were divided into two groups randomly-. Dimethyl sulfoxide (DMSO) control group (n =6)and FK224 group (n =6). Guinea pigs were anesthetized with pentobarbital sodium. A cervical tracheostomy wasperformed and a polyethylene tube was inserted into the trachea. After measuring baseline value of the lung resist-ance (RL) and dynamic compliance of respiratory system (Cdyn), DMSO (0.3 ml/kg) and FK224 (1mg/kg) wereadministered by injection through jugular vein respectively. A rodent respirator with dry 5% CO2-95% O2 mixture atroom temperature provided mechanical ventilation ( VT 8ml/animal, 100breaths/min) for 5min. RL and Cdyn of 2groups were measured after isocapnic hyperpnea challenge. Results In DMSO control group, isocapnic hyper-pnea of dry gas elicited a marked increase in RL and decrease in Cdyn. RL and Cdyn of FK224 group did not changesignificantly. Conclusion FK224 can inhibit the increase in RL and decrease in Cdyn caused by isocapnic hy-perpnea in guinea pigs. And antagonists of tachykinins receptors might have effect on prophylaxis and treatment inexercise-induced asthma.
基金supported by the Program of the National Natural Science Foundation of China (No. 51374214)National Science Foundation of China (No. 41040027)Fundamental Research Funds for the Central Universities (No. 2009QL06)
文摘The Shenbei mining area in China contains typical soft rock from the Tertiary Period. As mining depths increase, deep soft rock roadways are damaged by large deformations and constantly need to be repaired to meet safety requirements, which is a great security risk. In this study, the characteristics of deformation and failure of typical roadway were analyzed, and the fundamental reason for the roadway deformation was that traditional support methods and materials cannot control the large deformation of deep soft rock. Deep soft rock support technology was developed based on constant resistance energy absorption using constant resistance large deformation bolts. The correlative deformation mechanisms of surrounding rock and bolt were analyzed to understand the principle of constant resistance energy absorption. The new technology works well on-site and provides a new method for the excavation of roadwavs in Tertiary deed soft rock.
文摘In order to further reduce the sulfur content in liquid hydrocarbon fuels,a desulfurization process by adsorption for removing alkyl dibenzothiophenes was investigated.Desulfurization of model gasoline by bentonite adsorbents loaded with silver nitrate was studied.The test results indicated that the bentonite adsorbents loaded with Ag + ions were effective for adsorbing the alkyl dibenzothiophenes.The crystal structure of bentonite adsorbents was characterized by X-ray diffraction (XRD) and their acidity was measured by Fourier transform infrared (FT-IR) spectroscopy.Several factors influencing the desulfurization capability,including the Ag + loading,the baking temperature,as well as the reaction temperature,were investigated.The desulfurization efficiency was enhanced by increasing the Ag + loading and the best result was obtained at a silver loading of 7 m%.It was found that the adsorption capacity of the alkyl dibenzothiophenes on bentonite loaded with Ag + ions increased with a decreasing temperature.Baking of the adsorbent could also improve the desulfurization capacity,and the optimum baking temperature was 423 K.
文摘The absorption process of radiative heat in its transmission medium and the effect of ultra-attenuation on the radiative characteristics are analyzed in detail. A method of ultra-attenuation to enhance the radiative characteristics of the medium is proposed. It is proved that decreasing the particle size of coatings can increase the transmission depth of radiative heat and get higher emissivity and absorptivity both theoretically and practically. Ultra-attenuation and nanocrystallization will bring a brilliant prospect to the development of radiative coatings.
