Edge-defined, film-fed growth (EFG) technique for the preparation of alpha-Al2O3 : C crystal with highly sensitive thermoluminescence response

In this work, alpha-Al2O3:C, a highly sensitive thermoluminescence dosimetry crystal, was grown by the EFG method in which a graphite heating unit and shield acted as the carbon source during the growth process. The optical, luminescent properties and dosimetric characteristics of the crystal were investigated. The as-grown crystal shows a single glow peak at 536 K, which is associated with Cr3+ ions. After annealing in H-2 at 1673 K for 80 h, the crystal shows a single glow peak at 460 K and a blue emission band at 415 nm. The thermoluminescent response of the annealed crystal shows linear-sublinear-saturation characteristics in the dose range from 5 x 10(-6) to 100 Gy.

Endocrine disrupting effects on Chinese rare minnow (Gobiocypris rarus) fed with field collected Limnodrilus sp.

The potential endocrine disrupting effects and other toxicity effects on aquatic biota resulted from food uptake was simulated by feeding the laboratory cultured rare minnow(Gobiocypris rarus) with field collected Limnodrilus sp. The results indicated that the food chain processes affected significantly the growth, slightly reduced gonadosomatic indices, and elevated hepatosomatic indices. There was an obvious vitellogenin(VTG) induction, which generally only occurred in mature female, in the serum of juvenile rare minnow and mature male when fed with Limnodrilus sp. In addition, the rare minnow feeding on Limnodrilus sp. had significantly high renal indices, it meant obvious renal hyperplasia. The present work suggested that. Limnodrilus sp. from field water may contain toxic pollutants and could lead to endocrine disruption effects to the predators. It was concluded that endocrine disruptors may not only be assimilated through water, but also be bioconcentrated through food web. The results also suggested the importance of food selection in conducting the study of endocrine disruption effects using sensitive species.

Effect of a feeding stimulant on feeding adaptation of gibel carp Carassius auratus gibelio (Bloch), fed diets with replacement of fish meal by meat and bone meal

The objectives of the study were to investigate the effect of a feeding stimulant on feeding adaptation of gibel carp (Carassius auratus gibelio Bloch) fed diets with replacement of fish meal by meat and bone meal (MBM), and whether or not the juvenile gibel carp could adapt to higher MBM level in the diet. Juvenile and adult gibel carp were tested. Two and one replacement levels were used for juvenile and adult fish respectively. Each group of diets was set as two types with or without a unique rare earth oxide: Y2O3, Yb2O3, La2O3, Sm2O3, Nd2O3 or Gd2O3 (only the first four rare earth oxides were used in adult diets) for four adaptation periods of 3, 7, 14 and 28 days respectively. After mixing, an equal mixture of all six diets for juvenile or four diets for adult was offered in excess for 2 days. During the last 2 days of each experiment, no feed was offered and faeces from each tank were collected. Feeding preference was expressed as relative feed intake of each diet, which was estimated based on the relative concentration of each marker in the faeces. Given some adaptation period, such as 3-28 days, the effects of MBM and squid extract inclusion on the preference to each diet were reduced. After 28 days adaptation, the preferences between groups were not significantly different.

Life history characteristics of three types of females in Brachionus calyciflorus Pallas (Rotifera) fed different algae

This study describes the life history characteristics of amictic, unfertilized mictic and fertilized mictic females of the rotifer Brachionus calyciflorus cultured individually on two different algae at 0.1 mg ml(-1) food concentration and 27 degreesC. The duration of the juvenile period of amictic females was significantly shorter on Chlorella pyrenoidosa Chick than on Scenedesmus obliquus Kutz or both algae together. The duration of the juvenile period of unfertilized mictic females was significantly longer, and the number of eggs produced by amictic females was significantly larger on Chlorella pyrenoidosa than on S. obliquus. When fed the same type of alga, the duration of the juvenile period of the fertilized mictic females was the longest among the three types of females, and the durations of the reproductive period of the amictic females and the post-reproductive period of the fertilized mictic females were longer than, or equal to those of the other two types of females, respectively. The number of eggs produced by an unfertilized mictic female was the largest among the three types of females, and that of amictic females was larger than or equal to that of fertilized mictic females, depending on the type of diet.

Effect of several feeding stimulants on diet preference by juvenile gibel carp (Carassius auratus gibelio), fed diets with or without partial replacement of fish meal by meat and bone meal

The objectives of this work were to study the effects of several feeding stimulants on gibel carp fed diets with or without replacement of fish meal by meat and bone meal (MBM). The feeding stimulants tested were betaine, glycine, L-lysine, L-methionine, L-phenylalanine, and a commercial squid extract. Three inclusion levels were tested for each stimulant (0.18, 0.5%, and 1% for betaine and 0.1, 0.25 and 0.5% for the other stimulants). Two basal diets (40% crude protein) were used. one with 26% fish meal (FM), and the other with 21% fish meal and 6% MBM, Betaine at 0.1% in the fish meal group and at 0.5% in the meat and bone meal group was used in all experiments for comparison among stimulants. In the experiment on each stimulant, six tanks of fish were equally divided into two groups, one fed the FM diet, and the other fed the MBM diet. After 7 days' adaptation to the basal diet, in which the fish were fed to satiation twice a day, the fish were fed for another 7 days an equal mixture of diets containing varying levels of stimulants. Each diet contained a unique rare earth oxide as inert marker (Y2O3, Yb2O3, La2O3, Sm2O3 or Nd2O3). During the last 3 days of the experiment, faeces from each tank were collected. Preference for each diet was estimated based on the relative concentration of each marker in the faeces. Gibel carp fed the FM diet had higher intake than those fed the MBM diet, but the difference was significant only in the experiments on betaine, glycine and L-methionine. None of the feeding stimulants tested showed feeding enhancing effects in FM diets. All feeding stimulants showed feeding enhancing effects in MBM diets. and the optimum inclusion level was 0.5% for betaine, 0.1% for glycine, 0.25% for L-lysine, 0.1% for L-methionine. 0.25% For L-phenylalanine. and 0.1% for squid extract. The squid extract had the strongest stimulating effect among all the stimulants tested. (C) 2001 Elsevier Science B.V. All rights reserved.

Growth of juvenile Chinese sturgeon Acipenser sinensis fed live and formulated diets

Triplicate groups of 3.8-g juvenile Chinese sturgeon Acipenser sinensis were reared for 8 weeks in indoor flow-through systems on one of four diets: a natural diet consisting solely of live tubificid worms, a semimoist practical diet, a dry practical diet, and a purified diet. The formulated diets were prepared in the laboratory and had protein contents of 47-50%. Except for the group fed the purified diet, fish showed high survival (94-96%) and growth (final weight, 41-45 g). Survival and specific growth rate did not differ significantly between groups fed the natural, semimoist, and dry practical diets, but were significantly (P < 0.05) lower in fish fed the purified diet. Proximate analysis showed that fish fed purified diet had lower protein and lipid levels but a higher moisture content than fish fed other diets. Our results demonstrated that growth and survival of cultured juvenile Chinese sturgeon fed practical diets were comparable with those fed live tubificid worms. However, Chinese sturgeon fed a purified diet showed inferior growth and survival.

Whole-body amino acid pattern of F-4 human growth hormone gene-transgenic red common carp (Cyprinus carpio) fed diets with different protein levels

F-4 generation of human growth hormone (hGH) gene-transgenic red common carp, and the non-transgenic controls were fed for 8 weeks on purified diets with 20%, 30% or 40% protein. Analysis of whole-body amino acids showed that the proportions of lysine, leucine, phenylalanine, valine and alanine, as percentages of body protein, increased significantly, while those of arginine, glutamic acid and tyrosine decreased, with increases in dietary protein level in at least one strain of fish. Proportions of the other amino acids were unaffected by the diets. The proportions of lysine and arginine were significantly higher, while those of leucine and alanine were lower in the transgenics than in the controls in at least one diet group. Proportions of the other amino acids were unaffected by strain. The results suggest that the whole-body amino acid profile of transgenic carp, when expressed as proportions of body protein, was in general, similar to that of the non-transgenic controls. (C) 2000 Elsevier Science B.V. All rights reserved.

Growth and feed utilization by F-4 human growth hormone transgenic carp fed diets with different protein levels

The F-4 generation of human growth hormone (hGH) transgenic red common carp Cyprinus carpio had significantly higher growth rates than the non-transgenic controls. Protein and energy intakes were significantly higher in the transgenic carp than in the controls fed the 20% protein diet, but were not different between the two strains fed diets with 30 and 40% protein. Faecal protein loss, as a proportion of protein intake, was significantly lower in the transgenics than in the controls fed diets with 20 and 30% protein, but was not different between the two strains Fed diet with 40% protein. Faecal energy loss, as a proportion of energy intake, was significantly lower in the transgenics than in the controls fed diet with 20% protein, but was not different between the two strains fed diets with 30 and 40% protein. Recovered protein, as a proportion of protein intake, was significantly higher in the transgenics than in the controls fed all diets, whereas recovered energy was significantly higher in the transgenic fish fed the 40% protein diet. For fish fed each diet, the transgenics had significantly higher body contents of dry matter and protein, but lower contents of lipid than the controls. It was concluded that transgenics were more efficient in utilizing dietary protein than the controls. it a lower dietary protein level; transgenics achieved higher growth rates mainly by increasing feed intake; at higher levels of dietary protein, transgenics achieved higher growth rates mainly through a higher energy conversion efficiency. (C) 1998 The Fisheries Society of the British Isles.

LABORATORY OBSERVATIONS ON THE CIRCADIAN FEEDING PATTERNS IN THE GRASS CARP (CTENOPHARYNGODON-IDELLA VAL) FED 3 DIFFERENT DIETS

Feeding intensities (number of bites per minute) were recorded each hour over a 24-h diel cycle for young grass carp fed three diets. The grass carp did not show distinct meals. Grass carp receiving plant diets (duckweed or elodea) fed almost continuously throughout the 24 h, while fish fed the animal diet (tubificids) ceased feeding or had very low feeding intensities for about a quarter of the diel cycle. The average feeding intensity in fish fed duckweed was three times higher than that in fish fed elodea and tubificids. Average dry matter intake per bite was much higher in fish fed the animal diet than in those fed the plant diets. In most individuals, there was no significant difference in feeding intensity between daytime and nighttime.

场发射(FED)用荧光粉的研制与改性

场发射平板显示器（Field Emission Displays, FED）是一种新发展起来的平板显示器，由于其在亮度、视角、响应时间、工作温度范围、能耗等方面具有优良的特性，成为近年新型显示器研究的热点之一。为实现高效的FED红、绿、蓝全色显示，荧光粉在其中起着十分重要的作用。制备性能优良的场发射用彩色荧光粉是决定将来FED技术成功与否的关键因素之一。 本论文研究的内容包括场发射(FED)用荧光粉的研制和改性工作。在场发射(FED)用荧光粉研制方面，采用溶胶-凝胶方法，制备了一系列新型场发射(FED)用荧光粉，包括稀土离子激活的镓酸镧 [(LaGaO3: Re3+ (Re = Eu, Tb, Dy, Tm, Sm)]体系、铟酸钙[(CaIn2O4: Re3+ (Re = Eu, Pr, Tb, Dy,)]体系、铟酸锶[(SrIn2O4: Re3+ (Re = Pr, Tb, Dy)]体系、镓酸镥[Lu3Ga5O12:Re3+ (Re = Eu, Tb，Pr)]体系，并研究了Pr, Sm, Eu, Tb, Dy, Tm等稀土离子在这些基质中的光致发光、低压阴极射线发光性质和能量传递等性质。在荧光粉的改性方面，采用喷雾热解法制备了Sr2CeO4球形场发射用荧光粉，研究了喷雾前驱体溶液中，聚乙二醇浓度、金属离子浓度、烧结温度对形貌及发光性能的影响；采用溶胶－凝胶方法成功将SiO2表明包覆一层CaTiO3:Pr3+, Y3Al5O12:Ce3+/Tb3+荧光粉，得到单分散，球形形貌，分布均匀，具有核/壳结构的球形荧光粉；另外研究了不同的制备方法对Ga2O3:Dy3+荧光粉的发光性能的影响。所得样品用XRD、FTIR、SEM、TEM、漫反射光谱、光致发光(PL)光谱、荧光寿命曲线、低压阴极射线(CL)光谱等进行表征。 在紫外光激发下，稀土离子激活的镓酸镧彩色荧光粉有基质(LaGaO3)的发射和稀土离子(Eu3+, Tb3+, Dy3+, Tm3+, Sm3+)的特征发射，研究表明在基质和稀土离子之间存在能量传递，其能量传递效率因离子而异。在阴极射线激发下，样品仅有稀土离子(Eu3+, Tb3+, Dy3+, Tm3+, Sm3+)的特征发射。如：LaGaO3: Eu3+发红光，LaGaO3: Dy3+发白光，LaGaO3: Tm3+发蓝光，LaGaO3: Sm3+发黄光，LaGaO3: Sm3+,Tb3+发白光。LaGaO3: Tb3+的发光颜色可通过不同Tb3+的掺杂浓度从蓝光到绿光进行调控。在相同的激发条件下，所制备的蓝光发射的LaGaO3: Tb3+和LaGaO3: Tm3+荧光粉与商业FED用蓝粉(Y2SiO5: Ce3+，日亚化学工业株式会社，NP-1047)相比具有更好的色纯度和更高的发光效率；所制备的黄光发射的LaGaO3: Sm3+荧光粉与商业低压黄色荧光粉((Zn,Cd)S: Ag，日亚化学工业株式会社，NP-1020)相比，色纯度接近，但具有更高的发光效率。并首次实现了单一基质中白光发射(LaGaO3: Sm3+,Tb3+), 所制备的稀土离子激活的镓酸镧彩色荧光粉[(LaGaO3: Re3+ (Re = Eu, Tb, Dy, Tm, Sm )]在场发射器件有潜在的应用。 在稀土离子掺杂的Sr/CaIn2O4荧光粉体系中，在基质Sr/CaIn2O4和掺杂离子Pr3+/Tb3+/Dy3+存在高效能量传递。基质Sr/CaIn2O4吸收能量向激活离子Pr3+/ Tb3+/Dy3+传递，发射为稀土离子Pr3+/Tb3+/Dy3+的特征发射，发光强度、荧光寿命等符合应用要求，在低压电子束激发下，Sr/CaIn2O4: Pr3+/Tb3+/Dy3+荧光粉为稀土离子的特征发射，其低压阴极射线发光(CL)光谱与光致发光(PL)发射光谱一致，CL强度随激发电压，电流密度增加而增强。 对于CaIn2O4:Eu3+荧光粉，进一步研究表明CaIn2O4:Eu3+荧光粉的光致发光和阴极射线发光颜色可以通过掺杂不同浓度的Eu3+从白光，黄光，到红光进行调控。低浓度掺杂发白光，高浓度掺杂发红光，适当的浓度发黄光。 在Lu3Ga5O12:Re3+ (Re = Eu, Tb，Pr)荧光粉体系中，在紫外（UV）和低压阴极射线激发下，所制备的荧光粉Lu3Ga5O12: Eu3+, Lu3Ga5O12: Pr3+为稀土离子Eu3+, Pr3+的特征发射，分别发黄光和绿光。Lu3Ga5O12:Tb3+的发光颜色因Tb3+掺杂浓度不同而不同，低浓度掺杂发蓝光，高浓度发绿光。 Sr2CeO4荧光粉在UV及低压阴极射线激发下发出强烈蓝光，源于配体到金属离子电荷迁移带跃迁(Ce4+-O2-)。其阴极射线发光强度与电压及灯丝电流呈良好的线性关系。 采用溶胶－凝胶方法的核壳结构的SiO2@CaTiO3:Pr3+和SiO2@Y3Al5O12: Ce3+/Tb3+荧光粉, FESEM和TEM结果表明这种核壳结构的发光材料表面致密，厚度均匀，保持了单分散SiO2微球的形貌特征。在UV及低压阴极射线激发下，SiO2@CaTiO3:Pr3+呈强红色发射，源于Pr3+ 的1D2—3H4 (612 nm)跃迁；SiO2@Y3Al5O12:Ce3+和SiO2@Y3Al5O12:Tb3+ 分别发黄绿光和绿光，源于Ce3+的5d-4f和Tb3+的5D4-7FJ (J = 6, 5, 4, 3)跃迁。PL强度可以通过包覆次数调控，CL强度随激发电压及灯丝电流增加而增强。 在Ga2O3:Dy3+荧光粉体系中，采用了溶胶-凝胶，氨水共沉淀，和高温固相法制备了Ga2O3:Dy3+荧光粉并比较了他们的结晶行为，形貌，光致发光和低压阴极射线发光性能。溶胶-凝胶法制备由于原料在分子层次上混合，可以得到纯相，氨水共沉淀和高温固相法原料不如溶胶凝胶法混合均匀，很难得到纯相。溶胶-凝胶和氨水共沉淀所得荧光粉为纳米级别大小，分别呈球形和玉米棒形状；高温固相法微米级别且呈不规则形状。Ga2O3向Dy3+传递能量效率依次按溶胶-凝胶，氨水共沉淀，和高温固相法逐渐降低。在紫外光激发下，分别发白光，蓝白光，蓝光。其低压阴极射线发光与光致发光类似。相比之下，溶胶-凝胶法制备Ga2O3:Dy3+荧光粉比氨水共沉淀和高温固相法制备要好。