Explosive Reactive Armor was originally modeled under the assumption that the plates in the cassettes were very thin.Hence their thickness could be ignored,and the thicknesses of the plates were considered only based ...Explosive Reactive Armor was originally modeled under the assumption that the plates in the cassettes were very thin.Hence their thickness could be ignored,and the thicknesses of the plates were considered only based on their areal mass density.In particular,it was assumed that the jet-plate interaction was controlled by the plates to jet-mass-flux ratio criteria for a specific jet velocity and diameter.In the present study,we extended this analysis,examining the effect of the variation of the mass-flux along the jet on the disruption effect by the two plates.In addition,we examined the thickness effect of the plates on the plate's effectiveness,replacing the steel plates by low-density materials like aluminum and polycarbonate.The mass-flux model was adjusted to account for the plate-thickness effect.It was found that increasing the thickness of the plate,keeping the areal weight unchanged,slightly increases the overall effectiveness of the cassette,in particular by the forward moving plate interacting with the center and the slow parts of the jet.展开更多
Purpose To investigate the intraocular pressure (IOP) variations occurring aft er indirect diode laser photocoagulation for threshold retinopathy of prematurit y. Design Prospective, nonrandomized, comparative study. ...Purpose To investigate the intraocular pressure (IOP) variations occurring aft er indirect diode laser photocoagulation for threshold retinopathy of prematurit y. Design Prospective, nonrandomized, comparative study. Participants A study gr oup 21 consecutive premature babies (42 eyes) undergoing diode laser photocoagul ation for retinopathy of prematurity and control groups 32 premature babies (64 eyes) undergoing retinal examination with or without scleral indentation. Interv ention Intraocular pressure was measured with a portable electronic tonometer be fore, immediately after, and 1, 2, and 3 days after diode laser photocoagulation in the study group; before retinal examination in control group 1; and before a nd after retinal examination with scleral indentation in control group 2. Main o utcome measure Intraocular pressure after diode laser photocoagulation for thres hold retinopathy of prematurity. Results Mean IOP in the study group rose from 1 5 mmHg (standard deviation SD=4.1) before coagulation to 33.2 mmHg (SD = 7.8; range, 20-50) immediately after, and then dropped to 22.2 (SD=5.2), 16.5 (SD=3) , and 14.5 mmHg (SD=2.1) 1, 2, and 3 days later, respectively. All the changes w ere statistically significant at P < 0.0001, except for the difference between d ays 2 and 3(P=0.096). Mean baseline IOPs were 16.3 mmHg (SD=3.7) in control grou p 1 and 15.7 mmHg (SD=2.3) in control group 2 (P=0.84 between control group 1 an d study group, and P=0.32 between control group 2 and the study group). At termi nation of the retinal examination with scleral indentation (control group 2), IO P measured 15.1 mmHg (SD=2.2) (P=0.49 compared with baseline). Conclusions Intra ocular pressure may be significantly elevated after diode laser photocoagulation for retinopathy of prematurity. The mechanism and long-term clinical implicati ons of this observation should be investigated.展开更多
文摘Explosive Reactive Armor was originally modeled under the assumption that the plates in the cassettes were very thin.Hence their thickness could be ignored,and the thicknesses of the plates were considered only based on their areal mass density.In particular,it was assumed that the jet-plate interaction was controlled by the plates to jet-mass-flux ratio criteria for a specific jet velocity and diameter.In the present study,we extended this analysis,examining the effect of the variation of the mass-flux along the jet on the disruption effect by the two plates.In addition,we examined the thickness effect of the plates on the plate's effectiveness,replacing the steel plates by low-density materials like aluminum and polycarbonate.The mass-flux model was adjusted to account for the plate-thickness effect.It was found that increasing the thickness of the plate,keeping the areal weight unchanged,slightly increases the overall effectiveness of the cassette,in particular by the forward moving plate interacting with the center and the slow parts of the jet.
文摘Purpose To investigate the intraocular pressure (IOP) variations occurring aft er indirect diode laser photocoagulation for threshold retinopathy of prematurit y. Design Prospective, nonrandomized, comparative study. Participants A study gr oup 21 consecutive premature babies (42 eyes) undergoing diode laser photocoagul ation for retinopathy of prematurity and control groups 32 premature babies (64 eyes) undergoing retinal examination with or without scleral indentation. Interv ention Intraocular pressure was measured with a portable electronic tonometer be fore, immediately after, and 1, 2, and 3 days after diode laser photocoagulation in the study group; before retinal examination in control group 1; and before a nd after retinal examination with scleral indentation in control group 2. Main o utcome measure Intraocular pressure after diode laser photocoagulation for thres hold retinopathy of prematurity. Results Mean IOP in the study group rose from 1 5 mmHg (standard deviation SD=4.1) before coagulation to 33.2 mmHg (SD = 7.8; range, 20-50) immediately after, and then dropped to 22.2 (SD=5.2), 16.5 (SD=3) , and 14.5 mmHg (SD=2.1) 1, 2, and 3 days later, respectively. All the changes w ere statistically significant at P < 0.0001, except for the difference between d ays 2 and 3(P=0.096). Mean baseline IOPs were 16.3 mmHg (SD=3.7) in control grou p 1 and 15.7 mmHg (SD=2.3) in control group 2 (P=0.84 between control group 1 an d study group, and P=0.32 between control group 2 and the study group). At termi nation of the retinal examination with scleral indentation (control group 2), IO P measured 15.1 mmHg (SD=2.2) (P=0.49 compared with baseline). Conclusions Intra ocular pressure may be significantly elevated after diode laser photocoagulation for retinopathy of prematurity. The mechanism and long-term clinical implicati ons of this observation should be investigated.
