A theoretical model of relationship between subsurface damage and surface roughness was established to realize rapid and non-destructive measurement of subsurface damage of ground optical materials.Postulated conditio...A theoretical model of relationship between subsurface damage and surface roughness was established to realize rapid and non-destructive measurement of subsurface damage of ground optical materials.Postulated condition of the model was that subsurface damage depth and peak-to-valley surface roughness are equal to depth of radial and lateral cracks in brittle surface induced by small-radius(radius≤200 μm)spherical indenter,respectively.And contribution of elastic stress field to the radial cracks propagation was also considered in the loading cycle.Subsurface damage depth of ground BK7 glasses was measured by magnetorheological finishing spot technique to validate theoretical ratio of subsurface damage to surface roughness.The results show that the ratio is directly proportional to load of abrasive grains and hardness of optical materials,while inversely proportional to granularity of abrasive grains and fracture toughness of optical materials.Moreover,the influence of the load and fracture toughness on the ratio is more significant than the granularity and hardness,respectively.The measured ratios of 80 grit and 120 grit fixed abrasive grinding of BK7 glasses are 5.8 and 5.4,respectively.展开更多
The flowing mechanism of a low permeability gas reservoir is different from a conventional gas reservoir,especially for that with higher irreducible water saturation the threshold pressure gradient exists. At present,...The flowing mechanism of a low permeability gas reservoir is different from a conventional gas reservoir,especially for that with higher irreducible water saturation the threshold pressure gradient exists. At present,in all the deliverability equation,the additional pressure drop caused by the threshold pressure gradient is viewed as constant,but this method has big error in the practical application. Based on the non-Darcy steady flow equation,the limited integral of the additional pressure drop is solved in this paper and it is realized that the additional pressure drop is not a constant but has something to do with production data,and a new deliverability equation is derived,with the relevant processing method for modified isochronal test data. The new deliverability equation turns out to be practical through onsite application.展开更多
This experiment was conducted at College of Agriculture, University of Sulaimany to study the effect of different levels of Flax seed powder （FP） as a source of omega-3 on the carcass characteristics of Karadi Iambs...This experiment was conducted at College of Agriculture, University of Sulaimany to study the effect of different levels of Flax seed powder （FP） as a source of omega-3 on the carcass characteristics of Karadi Iambs. It used 20 male Karadi lambs, with an average live-weight of 28 ± 0.398 kg and 4-5 months. They were randomly distributed to 4 treatments. FP was supplemented at the levels of 3%, 6% and 9% compared with the control group for 88 days. At the end of the experiment 12 lambs were slaughtered after overnight fasting of feed. Carcasses were chilled for 24 h at 4 ℃. Then, several measurements of carcass characteristics were taken. The results showed： no significant differences have been shown in relation to daily feed intake, live weight gain and feed conversion ratio. The treatment 9% recorded the highest in hot carcass weight （HCW） and cold carcass weight （CCW）, rib eye area （REA） and the lowest fat thickness of subcutaneous fat as compared to other treatments. While, no significant differences in dressing percentage （DP） were seen between treatments. Generally percentage of tail fat related to carcass weight and subcutaneous fat to intermuscular fat ratio decreased with FP supplementation. About carcass cuts, significant （P 〈 0.05） differences were seen in percentage of major carcass cuts （leg, rack, loin and shoulder） and secondary cuts （neck, foreshank, flank and breast cuts） relative to cold carcass weight. It can be concluded that using Flax seed powder （FP） as a source of omega-3 supplementation improved carcass characteristics and efficiency of meat production.展开更多
基金Project(50375156) supported by the National Natural Science Foundation of China
文摘A theoretical model of relationship between subsurface damage and surface roughness was established to realize rapid and non-destructive measurement of subsurface damage of ground optical materials.Postulated condition of the model was that subsurface damage depth and peak-to-valley surface roughness are equal to depth of radial and lateral cracks in brittle surface induced by small-radius(radius≤200 μm)spherical indenter,respectively.And contribution of elastic stress field to the radial cracks propagation was also considered in the loading cycle.Subsurface damage depth of ground BK7 glasses was measured by magnetorheological finishing spot technique to validate theoretical ratio of subsurface damage to surface roughness.The results show that the ratio is directly proportional to load of abrasive grains and hardness of optical materials,while inversely proportional to granularity of abrasive grains and fracture toughness of optical materials.Moreover,the influence of the load and fracture toughness on the ratio is more significant than the granularity and hardness,respectively.The measured ratios of 80 grit and 120 grit fixed abrasive grinding of BK7 glasses are 5.8 and 5.4,respectively.
基金National Basic Research Program of China(2007CB209506)
文摘The flowing mechanism of a low permeability gas reservoir is different from a conventional gas reservoir,especially for that with higher irreducible water saturation the threshold pressure gradient exists. At present,in all the deliverability equation,the additional pressure drop caused by the threshold pressure gradient is viewed as constant,but this method has big error in the practical application. Based on the non-Darcy steady flow equation,the limited integral of the additional pressure drop is solved in this paper and it is realized that the additional pressure drop is not a constant but has something to do with production data,and a new deliverability equation is derived,with the relevant processing method for modified isochronal test data. The new deliverability equation turns out to be practical through onsite application.
文摘This experiment was conducted at College of Agriculture, University of Sulaimany to study the effect of different levels of Flax seed powder （FP） as a source of omega-3 on the carcass characteristics of Karadi Iambs. It used 20 male Karadi lambs, with an average live-weight of 28 ± 0.398 kg and 4-5 months. They were randomly distributed to 4 treatments. FP was supplemented at the levels of 3%, 6% and 9% compared with the control group for 88 days. At the end of the experiment 12 lambs were slaughtered after overnight fasting of feed. Carcasses were chilled for 24 h at 4 ℃. Then, several measurements of carcass characteristics were taken. The results showed： no significant differences have been shown in relation to daily feed intake, live weight gain and feed conversion ratio. The treatment 9% recorded the highest in hot carcass weight （HCW） and cold carcass weight （CCW）, rib eye area （REA） and the lowest fat thickness of subcutaneous fat as compared to other treatments. While, no significant differences in dressing percentage （DP） were seen between treatments. Generally percentage of tail fat related to carcass weight and subcutaneous fat to intermuscular fat ratio decreased with FP supplementation. About carcass cuts, significant （P 〈 0.05） differences were seen in percentage of major carcass cuts （leg, rack, loin and shoulder） and secondary cuts （neck, foreshank, flank and breast cuts） relative to cold carcass weight. It can be concluded that using Flax seed powder （FP） as a source of omega-3 supplementation improved carcass characteristics and efficiency of meat production.
