Effects of temperature and light intensity on the groWth rate of four species of benthic diatoms for feeding abalone were studied by using a novel method (in situ optical density measurement)which was simple, convenie...Effects of temperature and light intensity on the groWth rate of four species of benthic diatoms for feeding abalone were studied by using a novel method (in situ optical density measurement)which was simple, convenient, fast, accurate and reliable for determining biomass of benthic algae. The results showed that the favourable temperature and light intensity were as follows: for Amphora coffeaeformis, 30℃, 18 W/m2 for Cocconeis scutellum var. parv. 18℃, 20 W/m2; for Navicula Corymbosa, 18℃. 12.4 W/m2;for Navicula mollis, 24℃, 6 W/m2.展开更多
Orthodontic fixed appliance therapy is the commonest mode of treatment for most types of malocclusions (teeth irregularities). However, these materials are liable for microbial adhesion, which predisposes the wearer t...Orthodontic fixed appliance therapy is the commonest mode of treatment for most types of malocclusions (teeth irregularities). However, these materials are liable for microbial adhesion, which predisposes the wearer to increased microbial burden. The present study aims to evaluate, microbial adhesion and growth on commonly used orthodontic ligating materials (Teflon coated wire, stainless steel wire, elastic rings) under in vitro condition. Furthermore, the role of saliva on adhesion and microbial colonization on said materials was also assessed. Experiments were conducted with three different orthodontic ligating materials each in 6 numbers. Growth OD, metabolic activity and cell viability were the experimental variables in addition to SEM (Scanning Electron Microscopy) analysis performed. Results revealed irespective of the nature of the ligating materials, microbial adhesion and growth were observed in all the materials and suggested that the chosen materials promotes microbial adhesion. Nevertheless, stainless steel ligatures were less prone to adhesion compared to Teflon coated and elastic ligatures. Presence of saliva accelerates adhesion and growth.展开更多
In order to take advantage of the climate resources more effectively ac- cording to the local circumstances and to plan and develop the citrus industry in Southern Shaanxi more reasonably. On the basis of the investig...In order to take advantage of the climate resources more effectively ac- cording to the local circumstances and to plan and develop the citrus industry in Southern Shaanxi more reasonably. On the basis of the investigation of freeze dam- age to citrus occurring in Southern Shaanxi in the winter of 2010, the climatic back- ground for the formation of this freeze damage was analyzed. In combination with the freeze damage indicators during the overwintering period and the harmful accu- mulated cold during the cold wave, indexes for grading the freeze damage in southern Shaanxi were analyzed and verified, and the perspective of grading the freeze damage using the harmful accumulated cold during the cold wave was also presented. Through analyzing the extremely lowest temperature and the harmful ac- cumulated cold in the winter of 2010 and in history at 12 citrus growing counties （districts） in Ankang area and Hanzhong area, the reasons why the freeze damage to citrus during the overwintering period was severer in the west than in the east of Southern Shaanxi were discussed, and the results obtained were basically consistent with the actual situation observed from investigation. Finally, defensive countermea- sures against the freeze damage to citrus during the overwintering period were put forward from several aspects.展开更多
Ca 4GdO(BO 3) 3 (GdCOB) single crystal is a new nonlinear optical crystal whi ch was discovere d in recent years.It has a large effective nonlinear optical coefficient,a high damage threshold,good chemical and physica...Ca 4GdO(BO 3) 3 (GdCOB) single crystal is a new nonlinear optical crystal whi ch was discovere d in recent years.It has a large effective nonlinear optical coefficient,a high damage threshold,good chemical and physical properties and insensitivity to moi sture.Its moderate birefringence is favorable for phase matching.These propertie s make it possible to obtain frequency doubling laser of 1.064μm.By doping,it may be a excellent self frequency doubling crystal.Transparent single crystals GdCOB as needle were grown by the flux method. Chemical compounds Gd 2O 3,CaCO 3,B 2O 3 and H 3BO 3 were used as starti ng materials.By many experiments,with different ratio,it is proper to mix the st arting materials according to the reaction Gd 2O 3+8CaCO 3+6H 3BO 3=2 Ca 4 G dO(BO 3) 3+8CO 2+9H 2O.PbO was used as the main flux ,adding moderate PbF 2 , and B 2O 3.B 2O 3 also can be used as initial compounds and it is also a goo d solvent,but at high temperature,it has heavy viscousness.The crystals grown fr om B 2O 3 commonly has inclusion,so we used H 3BO 3 instead of B 2O 3.At t he same time,we considered that at high temperature H 3BO 3 will be decomposed and evaporated,which would make the initial composition change.When proper B 2 O 3 was added,it not noly can be used as solvent,but also can stabilize solvent component.The melt was contained in a platinum crucible.After holding the melt 1200℃ for 24h,it was cooled at a rate of 0.5℃ per hour.Single crystals GdCOB were obtained.With microscope,we observed the crystals have defects such as inc lusion and bubbles,which are related to rapid cooling,imperfect melt transport a nd unstable temperature.展开更多
文摘Effects of temperature and light intensity on the groWth rate of four species of benthic diatoms for feeding abalone were studied by using a novel method (in situ optical density measurement)which was simple, convenient, fast, accurate and reliable for determining biomass of benthic algae. The results showed that the favourable temperature and light intensity were as follows: for Amphora coffeaeformis, 30℃, 18 W/m2 for Cocconeis scutellum var. parv. 18℃, 20 W/m2; for Navicula Corymbosa, 18℃. 12.4 W/m2;for Navicula mollis, 24℃, 6 W/m2.
文摘Orthodontic fixed appliance therapy is the commonest mode of treatment for most types of malocclusions (teeth irregularities). However, these materials are liable for microbial adhesion, which predisposes the wearer to increased microbial burden. The present study aims to evaluate, microbial adhesion and growth on commonly used orthodontic ligating materials (Teflon coated wire, stainless steel wire, elastic rings) under in vitro condition. Furthermore, the role of saliva on adhesion and microbial colonization on said materials was also assessed. Experiments were conducted with three different orthodontic ligating materials each in 6 numbers. Growth OD, metabolic activity and cell viability were the experimental variables in addition to SEM (Scanning Electron Microscopy) analysis performed. Results revealed irespective of the nature of the ligating materials, microbial adhesion and growth were observed in all the materials and suggested that the chosen materials promotes microbial adhesion. Nevertheless, stainless steel ligatures were less prone to adhesion compared to Teflon coated and elastic ligatures. Presence of saliva accelerates adhesion and growth.
基金Supported by Shaanxi"13115"Public Service Platform Construction Program for Science&Technology Innovation Projects(2010FWPT-17)~~
文摘In order to take advantage of the climate resources more effectively ac- cording to the local circumstances and to plan and develop the citrus industry in Southern Shaanxi more reasonably. On the basis of the investigation of freeze dam- age to citrus occurring in Southern Shaanxi in the winter of 2010, the climatic back- ground for the formation of this freeze damage was analyzed. In combination with the freeze damage indicators during the overwintering period and the harmful accu- mulated cold during the cold wave, indexes for grading the freeze damage in southern Shaanxi were analyzed and verified, and the perspective of grading the freeze damage using the harmful accumulated cold during the cold wave was also presented. Through analyzing the extremely lowest temperature and the harmful ac- cumulated cold in the winter of 2010 and in history at 12 citrus growing counties （districts） in Ankang area and Hanzhong area, the reasons why the freeze damage to citrus during the overwintering period was severer in the west than in the east of Southern Shaanxi were discussed, and the results obtained were basically consistent with the actual situation observed from investigation. Finally, defensive countermea- sures against the freeze damage to citrus during the overwintering period were put forward from several aspects.
文摘Ca 4GdO(BO 3) 3 (GdCOB) single crystal is a new nonlinear optical crystal whi ch was discovere d in recent years.It has a large effective nonlinear optical coefficient,a high damage threshold,good chemical and physical properties and insensitivity to moi sture.Its moderate birefringence is favorable for phase matching.These propertie s make it possible to obtain frequency doubling laser of 1.064μm.By doping,it may be a excellent self frequency doubling crystal.Transparent single crystals GdCOB as needle were grown by the flux method. Chemical compounds Gd 2O 3,CaCO 3,B 2O 3 and H 3BO 3 were used as starti ng materials.By many experiments,with different ratio,it is proper to mix the st arting materials according to the reaction Gd 2O 3+8CaCO 3+6H 3BO 3=2 Ca 4 G dO(BO 3) 3+8CO 2+9H 2O.PbO was used as the main flux ,adding moderate PbF 2 , and B 2O 3.B 2O 3 also can be used as initial compounds and it is also a goo d solvent,but at high temperature,it has heavy viscousness.The crystals grown fr om B 2O 3 commonly has inclusion,so we used H 3BO 3 instead of B 2O 3.At t he same time,we considered that at high temperature H 3BO 3 will be decomposed and evaporated,which would make the initial composition change.When proper B 2 O 3 was added,it not noly can be used as solvent,but also can stabilize solvent component.The melt was contained in a platinum crucible.After holding the melt 1200℃ for 24h,it was cooled at a rate of 0.5℃ per hour.Single crystals GdCOB were obtained.With microscope,we observed the crystals have defects such as inc lusion and bubbles,which are related to rapid cooling,imperfect melt transport a nd unstable temperature.
