The muzzle blast overpressure induces disturbances in the flow field inside the crew compartment(FFICC)of a truck-mounted howitzer during the artillery firing.This overpressure is the primary factor preventing personn...The muzzle blast overpressure induces disturbances in the flow field inside the crew compartment(FFICC)of a truck-mounted howitzer during the artillery firing.This overpressure is the primary factor preventing personnel from firing artillery within the cab.To investigate the overpressure characteristics of the FFICC,a foreign trade equipment model was used as the research object,and a numerical model was established to analyze the propagation of muzzle blast from the muzzle to the interior of the crew compartment under extreme firing condition.For comparative verification,the muzzle blast experiment included overpressure data from both the flow field outside the crew compartment(FFOCC)and the FFICC,as well as the acceleration data of the crew compartment structure(Str-CC).The research findings demonstrate that the overpressure-time curves of the FFICC exhibit multi-peak characteristics,while the pressure wave shows no significant discontinuity.The enclosed nature of the cab hinders the dissipation of pressure wave energy within the FFICC,leading to sustained high-amplitude overpressure.The frameskin structure helps attenuate the impact of muzzle blast on the FFICC.Conversely,local high overpressure caused by the convex or concave features of the cab's exterior significantly amplifies the overpressure amplitude within the FFICC.展开更多
The SEIR epidemic model studied here includes constant inflows of new susceptibles, exposeds, infectives, and recovereds. This model also incorporates a population size dependent contact rate and a disease-related dea...The SEIR epidemic model studied here includes constant inflows of new susceptibles, exposeds, infectives, and recovereds. This model also incorporates a population size dependent contact rate and a disease-related death. As the infected fraction cannot be eliminated from the population, this kind of model has only the unique endemic equilibrium that is globally asymptotically stable. Under the special case where the new members of immigration are all susceptible, the model considered here shows a threshold phenomenon and a sharp threshold has been obtained. In order to prove the global asymptotical stability of the endemic equilibrium, the authors introduce the change of variable, which can reduce our four-dimensional system to a three-dimensional asymptotical autonomous system with limit equation.展开更多
BACKGROUND: The study aimed to estimate the value of embryonal natural orifice transluminal endoscopic surgery(ENOTES) in treating severe acute pancreatitis(SAP) complicated with abdominal compartment syndrome(ACS).ME...BACKGROUND: The study aimed to estimate the value of embryonal natural orifice transluminal endoscopic surgery(ENOTES) in treating severe acute pancreatitis(SAP) complicated with abdominal compartment syndrome(ACS).METHODS: The patients, who were randomized into an ENOTES group and an operative group, underwent ENOTES and laparotomy, respectively. The results and complications of the two groups were compared.RESULTS: Enterocinesia was observed earlier in the ENOTES group than in the operative group. Acute Physiology and Chronic Health Evaluation II(APACHE II) score of patients in the ENOTES group was lower than that of the operative group on the 1st, 3rd and 5th post-operative day(P<0.05). The cure rate was 96.87% in the ENOTES group, which was statistically different from 78.12% in the operative group(P<0.05). There were significant differences in complications and mortality between the two groups(P<0.01).CONCLUSION: Compared with surgical decompression, ENOTES associated with flexible endoscope therapy is an effective and minimal invasive procedure with less complications.展开更多
BACKGROUND: Fascia iliaca compartment nerve block(FICNB) has been an established technique for postoperative analgesia after surgery for femoral bone fracture. FICNB is technically easy, effective for postoperative pa...BACKGROUND: Fascia iliaca compartment nerve block(FICNB) has been an established technique for postoperative analgesia after surgery for femoral bone fracture. FICNB is technically easy, effective for postoperative pain control after operation for femoral bone fracture and decreases the complications induced by systemic analgesic drugs. The severity of postoperative pain is affected by genetics, cultural and social factors across the world. In this study we assessed the efficacy of fascia iliaca compartment nerve block when it is used as part of multimodal analgesia after surgery for femoral bone fracture.METHODS: An institution-based case control study was conducted from September, 2013 to May, 2014. All patients who had been operated on under spinal anesthesia for femoral bone fracture were included. The patients divided into a FICNB group(n=20) and a control group(n=20). The FICNB group was given 30 mL of 0.25% bupivacaine at the end of the operation. Postoperative pain was assessed within the f irst 24 hours, i.e. at 15 minutes, 2 hours, 6 hours, 12 hours and 24 hours using 100 mm visual analogue scale(VAS), total analgesic consumption, and the time for the f irst analgesic request.RESULTS: VAS pain scores were reduced within the f irst 24 hours after operation in the FICNB group compared wtih the control group. VAS scores at 2 hours were taken as median values(IQR) 0.00(0.00) vs.18.00(30.00), P=0.001; at 6 hours 0.00(0.00) vs. 34.00(20.75), P=0.000; at 24 hours 12.50(10.00) vs. 31.50(20.75), P=0.004; and at 12 hours(17.80±12.45) vs.(29.95±12.40), P=0.004, respectively. The total analgesic consumption of diclofenac at 12 and 24 hours was reduced in the FICNB group, and the time for the fi rst analgesic request was signifi cantly prolonged(417.50 vs. 139.25 minutes, P=0.000).CONCLUSIONS: A single injection for FICNB could lead to postoperative pain relief, reduction of total analgesic consumption and prolonged time for the fi rst analgesic request in the FICNB group after surgery for femoral bone fracture. We recommend FICNB for analgesia after surgery for femoral bone fracture and for patients with femoral bone fracture at the emergency department.展开更多
Liquid-filled compartment structure consists of a bulk steel plate with matrix blind holes which are filled with liquid and a steel front plate to seal up the liquid with rings and bolts.The liquid-filled compartment ...Liquid-filled compartment structure consists of a bulk steel plate with matrix blind holes which are filled with liquid and a steel front plate to seal up the liquid with rings and bolts.The liquid-filled compartment structure can resist the shaped charge warhead effectively.This paper presents experimental and theoretical investigations of the penetration ability of the residual shaped charge jet emerging from the liquid-filled compartment structure after the penetration process at different impact angles.On the basis of shock wave propagation theory,the influence of the liquid-filled compartment structure on jet stability is analysed.The interferences of the liquid backflow caused by a reflected shock wave and a back plate on jet stability under different impact angles are also examined.In addition,the range of the disturbed velocity segments of the jet at different impact angles and the penetration ability of the residual jet are obtained.A theoretical model is validated against the experimental penetration depths.展开更多
The stomach compartments of 51 Mongolian gazelles (Procapra guttrurosa) were weighed and the data were compared with total body weight. The total tissue weights ranged from 2.70% to 2.82% of body weight. Rumens were t...The stomach compartments of 51 Mongolian gazelles (Procapra guttrurosa) were weighed and the data were compared with total body weight. The total tissue weights ranged from 2.70% to 2.82% of body weight. Rumens were the heaviest, occupying about 75% of the total stomach, followed by reticulums (9%–11%), abomasums (8%–10%) and omasums (4%–6%). The weights of rumens were directly proportional to body weights and weights of omasums and abomasums were inversely related to body weights. Stomachs of the Mongolian gazelle were of the “mixed feeder” in terms of total weight and contribution of each compartment.展开更多
Nowadays, isotope environmental technique tends to be used as a reconnaissance tool , both qualitative and quantitative, to calculate the aquifer parameters particularly in carbonate rock aquifers. But, the hetero...Nowadays, isotope environmental technique tends to be used as a reconnaissance tool , both qualitative and quantitative, to calculate the aquifer parameters particularly in carbonate rock aquifers. But, the heterogeneous flow is still problematic when Lumped parameter Models are usually used to calculate the residence times and hydraulic parameters. However, Discrete State Compartment Model can provide a powerful model to heterogeneous medium. One such study was carried on in Dazha valley, where the environmental tritium was used as a tracer for determining hydrogeological parameters based on a discrete state compartment model展开更多
This report describes for the first time the effects of hyperbaric oxygen therapy with 253kPa on patients(n=24) with post - trauma acute compartment syndrome, and the relationship be-tween the prognosis of the syndrom...This report describes for the first time the effects of hyperbaric oxygen therapy with 253kPa on patients(n=24) with post - trauma acute compartment syndrome, and the relationship be-tween the prognosis of the syndrome and the changes of plasma fibronectin. Plasma fibronectin wasmeasured using single radial immunodiffusion both before and after therapy with hyperbaric oxygen,with 30 healthy people as control for plasma fibronectin. The results showed that the clinical symp-toms and signs of all 16 patients with acute compartment syndromes in early stage were significantlyimproved after 3 times of hyperbaric oxygen therapy and disappeared after 5 times withoutfasciotomy. Six patients who were treated with hyperbaric oxygen after fasciotomy showed reductionin the infection, and, edema of the injured limb However, the effects were less favorable for 2 pa-tients with necrosis although their clinical symptoms and signs were partially improved. Besides,we found that these patients’ plasma fibronectin concentrations were significantly afterhyperbaric oxygen therapy. The mean increase was 43 (18. 9％; P【0. 01), 61( 24. 7%, P【0. 01),49 (17. 2%, P【0. 01), 57 (17. 4%; P【0. 05) and 55 mg/L ( 16. 6%; P【0. 05) after 1, 2, 3, 4and 5 times of therapy, respectively. Plasma fibronectin concentrations returned to the level of thecontrols after 3 times of therapy (P】0. 05). After fourth and fifth therapy plasma fibronectin lev-els of the patients rose higher than those of the controls (P【0.05). The results suggest that hyperbaric oxygen therapy has a beneficial effect on patients withacute compartment syndrome in the early stage Hyperbaric oxygen therapy can reduce edema andskeletal muscle necrosis The method can be used to treat patients with acute compartmentsyndrome in early stage and as an effective adjunctive treatment after fasciotomy.展开更多
The clustering behavior of a mono-disperse granular gas is experimentally studied in an asymmetric two-compartment setup. Unlike the random clustering in either compartment in the case of symmetric configuration when ...The clustering behavior of a mono-disperse granular gas is experimentally studied in an asymmetric two-compartment setup. Unlike the random clustering in either compartment in the case of symmetric configuration when lowering the shaking strength to below a critical value, the directed clustering is observed, which corresponds to an imperfect pitchfork bifurcation. Numerical solutions of the flux equation using a modified simple flux function show qualitative agreements with the experimental results. The potential application of this asymmetric structure is discussed.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.U2341269)。
文摘The muzzle blast overpressure induces disturbances in the flow field inside the crew compartment(FFICC)of a truck-mounted howitzer during the artillery firing.This overpressure is the primary factor preventing personnel from firing artillery within the cab.To investigate the overpressure characteristics of the FFICC,a foreign trade equipment model was used as the research object,and a numerical model was established to analyze the propagation of muzzle blast from the muzzle to the interior of the crew compartment under extreme firing condition.For comparative verification,the muzzle blast experiment included overpressure data from both the flow field outside the crew compartment(FFOCC)and the FFICC,as well as the acceleration data of the crew compartment structure(Str-CC).The research findings demonstrate that the overpressure-time curves of the FFICC exhibit multi-peak characteristics,while the pressure wave shows no significant discontinuity.The enclosed nature of the cab hinders the dissipation of pressure wave energy within the FFICC,leading to sustained high-amplitude overpressure.The frameskin structure helps attenuate the impact of muzzle blast on the FFICC.Conversely,local high overpressure caused by the convex or concave features of the cab's exterior significantly amplifies the overpressure amplitude within the FFICC.
基金This research is supported by the NNSF of China (19971066)
文摘The SEIR epidemic model studied here includes constant inflows of new susceptibles, exposeds, infectives, and recovereds. This model also incorporates a population size dependent contact rate and a disease-related death. As the infected fraction cannot be eliminated from the population, this kind of model has only the unique endemic equilibrium that is globally asymptotically stable. Under the special case where the new members of immigration are all susceptible, the model considered here shows a threshold phenomenon and a sharp threshold has been obtained. In order to prove the global asymptotical stability of the endemic equilibrium, the authors introduce the change of variable, which can reduce our four-dimensional system to a three-dimensional asymptotical autonomous system with limit equation.
文摘BACKGROUND: The study aimed to estimate the value of embryonal natural orifice transluminal endoscopic surgery(ENOTES) in treating severe acute pancreatitis(SAP) complicated with abdominal compartment syndrome(ACS).METHODS: The patients, who were randomized into an ENOTES group and an operative group, underwent ENOTES and laparotomy, respectively. The results and complications of the two groups were compared.RESULTS: Enterocinesia was observed earlier in the ENOTES group than in the operative group. Acute Physiology and Chronic Health Evaluation II(APACHE II) score of patients in the ENOTES group was lower than that of the operative group on the 1st, 3rd and 5th post-operative day(P<0.05). The cure rate was 96.87% in the ENOTES group, which was statistically different from 78.12% in the operative group(P<0.05). There were significant differences in complications and mortality between the two groups(P<0.01).CONCLUSION: Compared with surgical decompression, ENOTES associated with flexible endoscope therapy is an effective and minimal invasive procedure with less complications.
文摘BACKGROUND: Fascia iliaca compartment nerve block(FICNB) has been an established technique for postoperative analgesia after surgery for femoral bone fracture. FICNB is technically easy, effective for postoperative pain control after operation for femoral bone fracture and decreases the complications induced by systemic analgesic drugs. The severity of postoperative pain is affected by genetics, cultural and social factors across the world. In this study we assessed the efficacy of fascia iliaca compartment nerve block when it is used as part of multimodal analgesia after surgery for femoral bone fracture.METHODS: An institution-based case control study was conducted from September, 2013 to May, 2014. All patients who had been operated on under spinal anesthesia for femoral bone fracture were included. The patients divided into a FICNB group(n=20) and a control group(n=20). The FICNB group was given 30 mL of 0.25% bupivacaine at the end of the operation. Postoperative pain was assessed within the f irst 24 hours, i.e. at 15 minutes, 2 hours, 6 hours, 12 hours and 24 hours using 100 mm visual analogue scale(VAS), total analgesic consumption, and the time for the f irst analgesic request.RESULTS: VAS pain scores were reduced within the f irst 24 hours after operation in the FICNB group compared wtih the control group. VAS scores at 2 hours were taken as median values(IQR) 0.00(0.00) vs.18.00(30.00), P=0.001; at 6 hours 0.00(0.00) vs. 34.00(20.75), P=0.000; at 24 hours 12.50(10.00) vs. 31.50(20.75), P=0.004; and at 12 hours(17.80±12.45) vs.(29.95±12.40), P=0.004, respectively. The total analgesic consumption of diclofenac at 12 and 24 hours was reduced in the FICNB group, and the time for the fi rst analgesic request was signifi cantly prolonged(417.50 vs. 139.25 minutes, P=0.000).CONCLUSIONS: A single injection for FICNB could lead to postoperative pain relief, reduction of total analgesic consumption and prolonged time for the fi rst analgesic request in the FICNB group after surgery for femoral bone fracture. We recommend FICNB for analgesia after surgery for femoral bone fracture and for patients with femoral bone fracture at the emergency department.
基金This research was supported by the National Natural Science Foundation of China(Grant No.11472115,11872214)the China Scholarship Council(201706845026).
文摘Liquid-filled compartment structure consists of a bulk steel plate with matrix blind holes which are filled with liquid and a steel front plate to seal up the liquid with rings and bolts.The liquid-filled compartment structure can resist the shaped charge warhead effectively.This paper presents experimental and theoretical investigations of the penetration ability of the residual shaped charge jet emerging from the liquid-filled compartment structure after the penetration process at different impact angles.On the basis of shock wave propagation theory,the influence of the liquid-filled compartment structure on jet stability is analysed.The interferences of the liquid backflow caused by a reflected shock wave and a back plate on jet stability under different impact angles are also examined.In addition,the range of the disturbed velocity segments of the jet at different impact angles and the penetration ability of the residual jet are obtained.A theoretical model is validated against the experimental penetration depths.
文摘The stomach compartments of 51 Mongolian gazelles (Procapra guttrurosa) were weighed and the data were compared with total body weight. The total tissue weights ranged from 2.70% to 2.82% of body weight. Rumens were the heaviest, occupying about 75% of the total stomach, followed by reticulums (9%–11%), abomasums (8%–10%) and omasums (4%–6%). The weights of rumens were directly proportional to body weights and weights of omasums and abomasums were inversely related to body weights. Stomachs of the Mongolian gazelle were of the “mixed feeder” in terms of total weight and contribution of each compartment.
文摘Nowadays, isotope environmental technique tends to be used as a reconnaissance tool , both qualitative and quantitative, to calculate the aquifer parameters particularly in carbonate rock aquifers. But, the heterogeneous flow is still problematic when Lumped parameter Models are usually used to calculate the residence times and hydraulic parameters. However, Discrete State Compartment Model can provide a powerful model to heterogeneous medium. One such study was carried on in Dazha valley, where the environmental tritium was used as a tracer for determining hydrogeological parameters based on a discrete state compartment model
文摘This report describes for the first time the effects of hyperbaric oxygen therapy with 253kPa on patients(n=24) with post - trauma acute compartment syndrome, and the relationship be-tween the prognosis of the syndrome and the changes of plasma fibronectin. Plasma fibronectin wasmeasured using single radial immunodiffusion both before and after therapy with hyperbaric oxygen,with 30 healthy people as control for plasma fibronectin. The results showed that the clinical symp-toms and signs of all 16 patients with acute compartment syndromes in early stage were significantlyimproved after 3 times of hyperbaric oxygen therapy and disappeared after 5 times withoutfasciotomy. Six patients who were treated with hyperbaric oxygen after fasciotomy showed reductionin the infection, and, edema of the injured limb However, the effects were less favorable for 2 pa-tients with necrosis although their clinical symptoms and signs were partially improved. Besides,we found that these patients’ plasma fibronectin concentrations were significantly afterhyperbaric oxygen therapy. The mean increase was 43 (18. 9％; P【0. 01), 61( 24. 7%, P【0. 01),49 (17. 2%, P【0. 01), 57 (17. 4%; P【0. 05) and 55 mg/L ( 16. 6%; P【0. 05) after 1, 2, 3, 4and 5 times of therapy, respectively. Plasma fibronectin concentrations returned to the level of thecontrols after 3 times of therapy (P】0. 05). After fourth and fifth therapy plasma fibronectin lev-els of the patients rose higher than those of the controls (P【0.05). The results suggest that hyperbaric oxygen therapy has a beneficial effect on patients withacute compartment syndrome in the early stage Hyperbaric oxygen therapy can reduce edema andskeletal muscle necrosis The method can be used to treat patients with acute compartmentsyndrome in early stage and as an effective adjunctive treatment after fasciotomy.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 11034010 and 11274354)the Chinese Academy of Sciences "Strategic Priority Research Program - SJ-10" (Grant No. XDA04020200)the Special Fund for Earthquake Research of China (Grant No. 201208011)
文摘The clustering behavior of a mono-disperse granular gas is experimentally studied in an asymmetric two-compartment setup. Unlike the random clustering in either compartment in the case of symmetric configuration when lowering the shaking strength to below a critical value, the directed clustering is observed, which corresponds to an imperfect pitchfork bifurcation. Numerical solutions of the flux equation using a modified simple flux function show qualitative agreements with the experimental results. The potential application of this asymmetric structure is discussed.
