In this article, the three-dimensional unsteady multiphase flow is simulated in the whole passage of Francis hydraulic turbine. The pressure pulsation is predicted and compared with experimental data at positions in t...In this article, the three-dimensional unsteady multiphase flow is simulated in the whole passage of Francis hydraulic turbine. The pressure pulsation is predicted and compared with experimental data at positions in the draft tube, in front of runner, guide vanes and at the inlet of the spiral case. The relationship between pressure pulsation in the whole passage and air admission is analyzed. The computational results show： air admission from spindle hole decreases the pressure difference in the horizontal section of draft tube, which in turn decreases the amplitude of low-frequency pressure pulsation in the draft tube; the rotor-stator interaction between the air inlet and the runner increases the blade-frequency pressure pulsation in front of the runner.展开更多
AIM: To investigate the relationship among the presence of ulcer lesions, underlying disease, and clinical course in patients with ischemic colitis. METHODS: The subjects were 41 patients (10 male and 31 female; mean ...AIM: To investigate the relationship among the presence of ulcer lesions, underlying disease, and clinical course in patients with ischemic colitis. METHODS: The subjects were 41 patients (10 male and 31 female; mean age 70 years) with ischemic colitis who were admitted to and received treatment in our hospital from 2000 to 2006. We compared their characteristics and analyzed the mean lengths of admission and fast- ing for 9 patients with ulcer lesions (ulcer group) and 32 without (non-ulcer group). RESULTS: The groups with presence and absence of ulcer differed significantly only in white blood cell (WBC) count. Lengths of fasting and admission were 7.9 d and 17.9 d for the ulcer group and 4.4 d and 10.7 d for the non-ulcer group, respectively, and significantly longer in the ulcer group (P = 0.0057 and 0.0001). There was no correlation between presence of ulcer and presence of underlying diseases. CONCLUSION: Lengths of fasting and admission were significantly longer in patients with ischemic colitis with ulcer than for those without ulcer.展开更多
BACKGROUND:The influence of surgical delay on mortality and morbidity has been studied extensively among elderly hip fracture patients.However,most studies only focus on the timing of surgery when patients have alread...BACKGROUND:The influence of surgical delay on mortality and morbidity has been studied extensively among elderly hip fracture patients.However,most studies only focus on the timing of surgery when patients have already been hospitalized,without considering pre-admission waiting time.Therefore,the present study aims to explore the infl uence of admission delay on surgical outcomes.METHODS:In this retrospective study,we recorded admission timing and interval from admission to surgery for included patient.Other covariates were also collected to control confounding.The primary outcome was 1-year mortality.The secondary outcomes were 1-month mortality,3-month mortality,ICU admission and postoperative pneumonia.We mainly used multivariate logistic regression to determine the effect of admission timing on postoperative outcomes.An additional survival analysis was also performed to assess the impact of admission delay on survival status in the fi rst year after operation.RESULTS:The proportion of patients hospitalized on day 0,day 1,day 2 after injury was 25.4%,54.7%and 66.3%,respectively.And 12.6%patients visited hospital one week later after injury.Mean time from admission to surgery was 5.2 days(standard deviation 2.8 days).Hospitalization at one week after injury was a risk factor for 1-year mortality(OR 1.762,95%CI 1.026–3.379,P=0.041).CONCLUSION:Admission delay of more than one week is signifi cantly associated with higher 1-year mortality.As a supplement to the current guidelines which emphasizes early surgery after admission,we also advocate early admission once patients get injured.展开更多
Device-to-Device(D2D) communication has been proposed as a promising implementation of green communication to benefit the existed cellular network.In order to limit cross-tier interference while explore the gain of sh...Device-to-Device(D2D) communication has been proposed as a promising implementation of green communication to benefit the existed cellular network.In order to limit cross-tier interference while explore the gain of short-range communication,we devise a series of distributed power control(DPC) schemes for energy conservation(EC)and enhancement of radio resource utilization in the hybrid system.Firstly,a constrained opportunistic power control model is built up to take advantage of the interference avoidance methodology in the presence of service requirement and power constraint.Then,biasing scheme and admission control are added to evade ineffective power consumption and maintain the feasibility of the system.Upon feasibility,a non-cooperative game is further formulated to exploit the profit in EC with minor influence on spectral efficiency(SE).The convergence of the DPC schemes is validated and their performance is confirmed via simulation results.展开更多
基金the National Natural Science Foundation of China (Grant No.50609020)Natural Science Foundation of Hubei Province (Grant No. 2006ABB040)
文摘In this article, the three-dimensional unsteady multiphase flow is simulated in the whole passage of Francis hydraulic turbine. The pressure pulsation is predicted and compared with experimental data at positions in the draft tube, in front of runner, guide vanes and at the inlet of the spiral case. The relationship between pressure pulsation in the whole passage and air admission is analyzed. The computational results show： air admission from spindle hole decreases the pressure difference in the horizontal section of draft tube, which in turn decreases the amplitude of low-frequency pressure pulsation in the draft tube; the rotor-stator interaction between the air inlet and the runner increases the blade-frequency pressure pulsation in front of the runner.
文摘AIM: To investigate the relationship among the presence of ulcer lesions, underlying disease, and clinical course in patients with ischemic colitis. METHODS: The subjects were 41 patients (10 male and 31 female; mean age 70 years) with ischemic colitis who were admitted to and received treatment in our hospital from 2000 to 2006. We compared their characteristics and analyzed the mean lengths of admission and fast- ing for 9 patients with ulcer lesions (ulcer group) and 32 without (non-ulcer group). RESULTS: The groups with presence and absence of ulcer differed significantly only in white blood cell (WBC) count. Lengths of fasting and admission were 7.9 d and 17.9 d for the ulcer group and 4.4 d and 10.7 d for the non-ulcer group, respectively, and significantly longer in the ulcer group (P = 0.0057 and 0.0001). There was no correlation between presence of ulcer and presence of underlying diseases. CONCLUSION: Lengths of fasting and admission were significantly longer in patients with ischemic colitis with ulcer than for those without ulcer.
文摘BACKGROUND:The influence of surgical delay on mortality and morbidity has been studied extensively among elderly hip fracture patients.However,most studies only focus on the timing of surgery when patients have already been hospitalized,without considering pre-admission waiting time.Therefore,the present study aims to explore the infl uence of admission delay on surgical outcomes.METHODS:In this retrospective study,we recorded admission timing and interval from admission to surgery for included patient.Other covariates were also collected to control confounding.The primary outcome was 1-year mortality.The secondary outcomes were 1-month mortality,3-month mortality,ICU admission and postoperative pneumonia.We mainly used multivariate logistic regression to determine the effect of admission timing on postoperative outcomes.An additional survival analysis was also performed to assess the impact of admission delay on survival status in the fi rst year after operation.RESULTS:The proportion of patients hospitalized on day 0,day 1,day 2 after injury was 25.4%,54.7%and 66.3%,respectively.And 12.6%patients visited hospital one week later after injury.Mean time from admission to surgery was 5.2 days(standard deviation 2.8 days).Hospitalization at one week after injury was a risk factor for 1-year mortality(OR 1.762,95%CI 1.026–3.379,P=0.041).CONCLUSION:Admission delay of more than one week is signifi cantly associated with higher 1-year mortality.As a supplement to the current guidelines which emphasizes early surgery after admission,we also advocate early admission once patients get injured.
基金This work has been partly supported by National Natural Science Foundation of China，National High Technology Research and Development Program of China (863 Program)
文摘Device-to-Device(D2D) communication has been proposed as a promising implementation of green communication to benefit the existed cellular network.In order to limit cross-tier interference while explore the gain of short-range communication,we devise a series of distributed power control(DPC) schemes for energy conservation(EC)and enhancement of radio resource utilization in the hybrid system.Firstly,a constrained opportunistic power control model is built up to take advantage of the interference avoidance methodology in the presence of service requirement and power constraint.Then,biasing scheme and admission control are added to evade ineffective power consumption and maintain the feasibility of the system.Upon feasibility,a non-cooperative game is further formulated to exploit the profit in EC with minor influence on spectral efficiency(SE).The convergence of the DPC schemes is validated and their performance is confirmed via simulation results.
