It was hypothesized that soil respiration can be affected by canopy composition. Hence, admixture of trees as a common forest management practice may cause significant change in the carbon cycling. This study was cond...It was hypothesized that soil respiration can be affected by canopy composition. Hence, admixture of trees as a common forest management practice may cause significant change in the carbon cycling. This study was conducted in a mixed spruce-beech stand at Solling forest in central Germany to investigate the effect of canopy composition on soil respiration. The canopy cover was classified in four major canopy classes （pure beech, pure spruce, mixed and gap）, and the area under each canopy class was identified as a sub-plot. Soil respiration in each sub-plot （n=4） was measured monthly from Jun 2005 to July 2006. Results show significant difference in annual soil respiration between the beech （359g·m^-2·a^-1 C） and gap （211 g·m^-2·a^-1 C） sub-plots. The estimation of the total below-ground carbon allocation （TBCA） based on a model given by Raich and Nadelhoffer revealed considerably higher root CO2 production in the beech sub-plot （231 g·m^-2·a^-1 C） compare to the gap sub-plot （51 g·m^-2·a^-1 C ）. The contribution of the root respiration to the total soil respiration was higher in the soil under the beech canopy （59%） compared with the soil in the gap （29%）. The findings suggested that the condition under the beech canopy may cause more desirable micro-site for autotrophic respiration and consequently higher CO2 release into the atmosphere.展开更多
In order to improve the utilization rate of foam,an arc jet nozzle was designed for precise dust control.Through theoretical analysis,the different demands of foam were compared amongst arc jets,flat jets and full con...In order to improve the utilization rate of foam,an arc jet nozzle was designed for precise dust control.Through theoretical analysis,the different demands of foam were compared amongst arc jets,flat jets and full cone jets when the dust source was covered identically by foam.It is proved that foam consumption was least when an arc jet was used.Foam production capability of an arc jet nozzle under different conditions was investigated through experiments.The results show that with the gas liquid ratio(GLR)increasing,the spray state of an arc jet nozzle presents successively water jet,foam jet and mist.Under a reasonable working condition range of foam production and a fixed GLR,foam production quantity increases at first,and then decreases with the increase of liquid supply quantity.When the inner diameter of the nozzle is 14 mm,the best GLR is 30 and the optimum liquid supply quantity is0.375 m^3/h.The results of field experiments show that the total dust and respirable dust suppression efficiency of arc jet nozzles is 85.8%and 82.6%respectively,which are 1.39 and 1.37 times higher than the full cone nozzles and 1.20 and 1.19 times higher than the fiat nozzles.展开更多
The aim of the study is to assess the possibility of intubation in each patient, the lyche to be difficult intubation, to fred all the causes of the difficult intubation, to fred and apply appropriate scales for diffi...The aim of the study is to assess the possibility of intubation in each patient, the lyche to be difficult intubation, to fred all the causes of the difficult intubation, to fred and apply appropriate scales for difficult intubation, to estimate the frequency of difficult intubation. Endotmcheal intubation is the basic reanimation procedure performed both in hospital and out-of-hospital settings. It is carded out whenever chest movements and spontaneous respiration are compromised. Respiratory arrest may occur for a variety of reasons （such as cardac arrest, coma of any origin, poisining） or direct damage to the airways, e.g. in various traumas （damages to the face, oropharynx, larynx, trachea, chest）. The basic endotracheal intubation kit contains： laryngoscope, endotracheal tubes, connectors （tube and Ambu bag connectors）, complete Ambu kit （face mask and bag）, 20 mL syringe for cuff inflating, suction apparatus, stylete, and Magill forceps. In order to assess the successfulness of endotracheal intubation, it is necessary first to identify patients who need to be intubated. With the aim of identifying such patients, numerous screening tests and scales have been created to predict difficult intubation. The best known and most commonly used are the Mallampati and Wilson classifications as well as the LEMON airway assessment method. Nevertheless, difficult intubation accounts for 1% of cases. It usually occurs when manipulation of the laryngoscope blade is not possible in obese patients and patients with short neck, in congenital restricted mouth opening, limited neck movement as well as limited temporomandibular joint mobility; in cases of edema, fibrosis and lesions of the tongue, pharynx and larynx; when there are anatomical variations and congenital malformations of the oral cavity, pharynx, larynx, head, neck and chest.展开更多
文摘It was hypothesized that soil respiration can be affected by canopy composition. Hence, admixture of trees as a common forest management practice may cause significant change in the carbon cycling. This study was conducted in a mixed spruce-beech stand at Solling forest in central Germany to investigate the effect of canopy composition on soil respiration. The canopy cover was classified in four major canopy classes （pure beech, pure spruce, mixed and gap）, and the area under each canopy class was identified as a sub-plot. Soil respiration in each sub-plot （n=4） was measured monthly from Jun 2005 to July 2006. Results show significant difference in annual soil respiration between the beech （359g·m^-2·a^-1 C） and gap （211 g·m^-2·a^-1 C） sub-plots. The estimation of the total below-ground carbon allocation （TBCA） based on a model given by Raich and Nadelhoffer revealed considerably higher root CO2 production in the beech sub-plot （231 g·m^-2·a^-1 C） compare to the gap sub-plot （51 g·m^-2·a^-1 C ）. The contribution of the root respiration to the total soil respiration was higher in the soil under the beech canopy （59%） compared with the soil in the gap （29%）. The findings suggested that the condition under the beech canopy may cause more desirable micro-site for autotrophic respiration and consequently higher CO2 release into the atmosphere.
基金supported by the National Natural Science Foundation of China(No.51474216)
文摘In order to improve the utilization rate of foam,an arc jet nozzle was designed for precise dust control.Through theoretical analysis,the different demands of foam were compared amongst arc jets,flat jets and full cone jets when the dust source was covered identically by foam.It is proved that foam consumption was least when an arc jet was used.Foam production capability of an arc jet nozzle under different conditions was investigated through experiments.The results show that with the gas liquid ratio(GLR)increasing,the spray state of an arc jet nozzle presents successively water jet,foam jet and mist.Under a reasonable working condition range of foam production and a fixed GLR,foam production quantity increases at first,and then decreases with the increase of liquid supply quantity.When the inner diameter of the nozzle is 14 mm,the best GLR is 30 and the optimum liquid supply quantity is0.375 m^3/h.The results of field experiments show that the total dust and respirable dust suppression efficiency of arc jet nozzles is 85.8%and 82.6%respectively,which are 1.39 and 1.37 times higher than the full cone nozzles and 1.20 and 1.19 times higher than the fiat nozzles.
文摘The aim of the study is to assess the possibility of intubation in each patient, the lyche to be difficult intubation, to fred all the causes of the difficult intubation, to fred and apply appropriate scales for difficult intubation, to estimate the frequency of difficult intubation. Endotmcheal intubation is the basic reanimation procedure performed both in hospital and out-of-hospital settings. It is carded out whenever chest movements and spontaneous respiration are compromised. Respiratory arrest may occur for a variety of reasons （such as cardac arrest, coma of any origin, poisining） or direct damage to the airways, e.g. in various traumas （damages to the face, oropharynx, larynx, trachea, chest）. The basic endotracheal intubation kit contains： laryngoscope, endotracheal tubes, connectors （tube and Ambu bag connectors）, complete Ambu kit （face mask and bag）, 20 mL syringe for cuff inflating, suction apparatus, stylete, and Magill forceps. In order to assess the successfulness of endotracheal intubation, it is necessary first to identify patients who need to be intubated. With the aim of identifying such patients, numerous screening tests and scales have been created to predict difficult intubation. The best known and most commonly used are the Mallampati and Wilson classifications as well as the LEMON airway assessment method. Nevertheless, difficult intubation accounts for 1% of cases. It usually occurs when manipulation of the laryngoscope blade is not possible in obese patients and patients with short neck, in congenital restricted mouth opening, limited neck movement as well as limited temporomandibular joint mobility; in cases of edema, fibrosis and lesions of the tongue, pharynx and larynx; when there are anatomical variations and congenital malformations of the oral cavity, pharynx, larynx, head, neck and chest.
