放养规格对银化期大西洋鲑生长的影响及生理响应机理

内分泌系统在调节大西洋鲑（Salmo salar L.）的银化过程中,除了要尽快建立更高效的渗透调节机制外,鱼体自身的生理反应变化还要更好地适应降海后的生活。试验研究了平均体质量（30.25±2.12）g（SW1）、（24.27±1.59）g（SW2）和（18.05±2.46）g（SW3）大西洋鲑,1～42 d光照周期为12L：12D;43～84 d为全光照下（24L：0D）的生长及生理响应机理。试验结果表明,SW2组大西洋鲑的肥满度、日增质量、饲料转化率、净增质量最高,与其他组差异显著（P〈0.05）。SW2组体质量、体长特定生长率均显著高于其他处理组（P〈0.05）,各组间体质量、体长变异系数差异显著（P〈0.05）。试验前6周不同处理组大西洋鲑体长变异系数差异不显著（P〉0.05）。后6周全光照时,SW1、SW2组体长变异系数显著增加,且SW1组显著高于其他组（P〈0.05）。SW3组的大西洋鲑体质量变异系数变化较大。前6周光照期为12L：12D时,SW1、SW2两组体质量变异系数差异不显著（P〉0.05）,后6周改为全光照时,3个处理组间体质量变异系数差异减小。但在84 d时,SW3组体质量变异系数显著高于其他组（P〈0.05）。随着养殖规格的增大,血红蛋白浓度升高,红细胞数目增加,说明鱼体需氧量增加。SW3组白细胞数目、淋巴细胞数目和中性粒细胞数目最高,表明鱼体抗病能力强。红细胞数目在SW1和SW2组间无显著差异（P〉0.05）,但均显著高于SW3组（P〈0.05）。血栓细胞数目随着放养规格的增加而下降,且在3个规格组之间差异显著（P〈0.05）。中性粒细胞数目在3个规格组之间并没有显著性差异（P〉0.05）。SW2组总蛋白、白蛋白含量最高,且各组间差异显著（P〈0.05）。总胆固醇、甘油三酯浓度随鱼体规格增大而增加（P〈0.05）,表明大西洋鲑血液和体内对能量的利用增强。SW2组代谢产物尿酸、尿素浓度最高,且SW1、SW2组的浓度值均显著高于SW3组（P〈0.05）。SW3组大西洋鲑血清中总胆红素显著高于其他两组（P〈0.05）。各组间大西洋鲑血清中葡萄糖浓度没有显著性差异（P〉0.05）。SW3组肌酸激酶浓度最高,但各组间没有显著性差异（P〉0.05）。该研究结果建议选择体质量（24.27±1.59）g的大西洋鲑开始银化,利于优化养殖条件、以较低成本增加单位水体养殖产量和苗种规模化生产。

原位一步法制备BTDA/4,4′-ODA/4,4′-SDA聚酰亚胺表面银化薄膜

采用原位一步自金属化的方法制备了具有反射性和导电性的表面银(Ag)化的聚酰亚胺(PI)薄膜,PI是由一种二酐(3,3′,4,4′-四羧基二苯酮酐,BTDA)和两种二胺(4,4′-二氨基二苯醚,4,4′-ODA与4,4′-二氨基二苯硫醚,4,4′-SDA)三元共聚而得,系统研究了4,4′-SDA的引入对薄膜性能及相态结构的影响.结果表明,4,4′-SDA的加入有助于银的还原和迁移,并利于薄膜导电性的提高,薄膜的反射率在两种二胺单体4,4′-ODA与4,4′-SDA的摩尔比为1比1时达到最佳.

长江口日本鳗鲡降海产卵洄游群体的银化指标研究

以长江口降海生殖洄游途中的日本鳗鲡为研究材料,对繁殖群体银化过程中体色、年龄、全长、体重及银化指标等特征作了分析。结果显示,依据"体侧黑色素沉积是否蔓延至胸鳍下缘"这一体色标准,可将日本鳗鲡洄游群体分为银化前期和银化期二个发育期。日本鳗鲡银化过程中,体型、胸鳍长、眼径、性腺指数呈递增趋势,消化道指数则呈递减趋势。主成分分析亦表明,银化期较银化前期的眼径和胸鳍增大,还具有较高的性腺指数和较低的消化道饱满度。由于日本鳗鲡的产卵场位于3000 km之遥的马里亚纳海沟,这些形态的修正可能是为了适应即将起始的长距离降海生殖洄游。根据银化指标所建立的判别方程,对雌、雄群体银化前期和银化期的判别分析均取得了95%以上的成功率。研究认为,长江口日本鳗鲡银化期的野外快速判别,亦可采用"眼径指数大于5"作为识别依据。

关于实现电冰箱管路焊接无银、低银化的探讨

过去电冰箱管路的钎焊大都采用银基钎料,价昂,又很紧缺。目前,一些厂家推出了若干种类的无银和低银钎料,如何按不同接头的特点、要求,合理选用钎料,实现电冰箱管路钎焊无银、低银化,本文作了简述。

银化把节能降耗作为摆脱困境的主要措施

银川化肥厂是个建厂三十多年的老企业。三十多年来,该厂为宁夏的农业发展做出过巨大贡献。但近年来由于种种原因所致,企业面临的困难很多。去年7月份全厂设备大检修之后,由于受市场冲击,产品销售极为困难。大量的产品积压,使企业资金无法周转,企业陷入困境,被迫宣布停产。 去年11月份,在上级领导部门的支持和帮助下,企业调整了领导班子,并积极组织开车投产。为尽早摆脱困境,1998年全厂要把节能降耗作为一项主要工作来抓。

养殖条件下山女鳟银化体色个体生产性状

以山女鳟(Oncorhynchus masou masou)群体中出现的银化体色个体为研究对象,系统研究了在人工养殖条件下银化体色个体在群体中所占比率、银化体色个体与正常体色个体的体色差异,以及银化体色个体生长性状等。结果表明:①群体中不同家系间银化体色个体所占比率在0～0.21范围内,采用3×2列联表法进行卡方检验,发现家系间银化体色个体比率存在极显著的差异[Pearsonχ2df=5=93.362,P(Asymp.Sig.=0.000)<0.01];②利用色差计L*a*b*色彩空间检测体色差异,银化体色个体与正常体色个体L*、a*和Ca*b值均存在显著差异(P<0.01),其中前者L*值在30.78～48.50范围内,后者在51.24～71.43范围内;③经过12个月的生长对比实验,银化体色个体与正常体色个体在生长上也存在极显著差异(P<0.01),其中,前者平均体重(113.72 g)明显低于后者平均体重(132.25 g);银化体色个体与正常体色个体在肥满度指标和特定生长率指标上也均存在极显著的差异(P<0.01),在不同的生长阶段两者特定生长率不同,而整个实验期间前者肥满度均低于后者。本研究为生产中山女鳟银化体色个体的利用和以体色为目标的选育工作提供了数据支持。

全雌大西洋鲑工厂化降海鲑培育技术

为探究全雌大西洋鲑(Salmo salar)银化技术,利用陆基循环养殖系统开展银化培育试验。历经3个月,共计银化培育约6.5万尾幼鲑,银化培育率达95%以上,降海前存活率达97.4%,降海后30 d内死亡率为0.7%。形成了操作简单、成活率和银化比例更高、体质更健壮的降海鲑培育方法。

Ag(I)-Catalyzed Addition of Cyclopropenones and Alcohols via C—C Bond Cleavage

An efficient method for the synthesis of α-phenylcinnamates via silver catalyzed C—C bond activation reaction of cyclopropenone and alcohol was developed.This protocol features a simple reaction system,specific regioselectivity,good functional group compatibility and good yields.It is of great significance for the later modification of natural products.

Preparation and Anti⁃arc Erosion Property of Ag Matrix Electrical Contact Material Reinforced by Novel Ti_(2)Cd

Due to their outstanding electrical contact properties,Cd-containing silver-matrix electrical contact materials can meet the requirements of high stability and long life for military defense and aerospace applications.In order to further reduce the Cd content under the premise of meeting the high-performance requirements,in this study,high-purity intermediate Ti_(2)Cd powder of MAX phase(Ti_(2)CdC)was synthesized with a pressureless technique and then applied to reinforce the Ag matrix.The Cd content of the as-prepared Ag/Ti_(2)Cd composites was actually reduced by 38.31%compared with conventional Ag/CdO material.Based on the systematic study of the effect of heat treatment temperature on the physical phase,morphology,interface and comprehensive physical properties of Ag/Ti_(2)Cd composites,the preferred samples(heat treated at 400°C for 1 h)showed high density(97.77%),low resistivity(2.34μΩ·cm),moderate hardness(90.8HV),high tensile strength(189.9 MPa),and exhibited good electrical contact performance after 40000 cycles of arc discharging under severe conditions(DC 28 V/20 A).The results of microscopic morphological evolution,phase change and elemental distribution of the electrical contact surface show that the combination of high stability of Ti_(2)Cd reinforcing phase,good interfacial bonding with Ag matrix and improved melt pool viscosity in the primary stage of arc erosion,results in low and stable contact resistance(average value 13.20 mΩ)and welding force(average value 0.6 N),low fluctuation of static force(2.2-2.5 N).The decomposition and absorption energy of Ti_(2)Cd and the arc extinguishing effect of Cd vapor are the main reasons for the stable arcing energy and arcing time of electric contacts in the late stage of arc erosion.

活性硫化物银片腐蚀性能的研究

为提高喷气燃料的质量,在实验室研究了喷气燃料中不同硫化物对银片腐蚀的性能。结果表明,活性硫化物会导致银片腐蚀,其主要因素是元素硫。硫醇和二硫化物在无元素硫的情况下不腐蚀银片,与元素硫共存时加重腐蚀程度并出现颜色多样性;高浓硫化氢腐蚀银片,颜色主要为紫、红或黄色;金属锈、酸根、洗衣粉等杂质不足以使银片腐蚀超过1级,酸碱度(pH 5～9)变化不影响硫化物银片腐蚀级别;非标准汽油含一定量的H_2S、S,混入喷气燃料将导致银片腐蚀。

脂肪酸的分析方法研究

用毛细管气相色谱法对十四碳到二十二碳的脂肪酸甲酯进行了分析 ,用气质联用法考察了用等效链长度 (ECL)值对未知脂肪酸进行定性的可能性 ,及银化薄层色谱法 (Ag- TLC)分离脂肪酸的特点。结果表明 ,用等效链长度值可以对大多数未知脂肪酸进行定性。

降海鲑渗透生理及入海窗口期的研究进展

在过去30年中,降海鲑的发育得到了大量关注,研究降海鲑的发育,特别是如何调控降海鲑发育的时间和品质,以便幼鲑移入海水网箱。洄游型鲑科鱼类幼鲑向降海鲑的转变包含了一系列的行为、形态、生理的改变,这都为降海洄游进入河口做准备。降海鲑发育受几种激素的促进,包括生长激素、胰岛素样生长因子-I、皮质醇、甲状腺素,而催乳素通常会抑制发育。鳃氯细胞中特殊的离子转运蛋白(NKA、Na+/K+/Cl-协同转运蛋白和Cl-通道)丰度的增加引起盐分泌能力的提高,从而有利于降海鲑在海水中生长、游泳和存活。具银化期的鲑科鱼类(如大西洋鲑(Salmo salar)、硬头鳟(Oncorhyunchus mykiss)、银大麻哈鱼(Oncorhynchus kisutch)至少在淡水中生活一年,达到临界最小规格之后才可改变其对光周期的响应。如果在银化前未达到这个最小规格,则需等到下一年(或更长)。鲑科鱼类如何在一年中合适的时间确定其规格或生长率,并增加对光周期的响应性,这一重要的领域还未得到大量的关注。因此,了解降海鲑渗透生理及入海窗口期,查明不同鱼类适宜生长盐度,入海时间和方式非常重要,可为鲑科鱼类(如虹鳟(Oncorhynchus mykiss)、硬头鳟等)在黄海冷水团规模化养殖提供理论支持。

Photochemical oxidation mechanism of microcystin-RR by p-n heterojunction Ag/Ag_2O-BiVO_4

Microcystin-RR（MC-RR）,a form of microcystin with two arginine moieties,is a cyanobacterial toxin that has been detected across a wide geographic range.It is a great concern globally because of its potential liver toxicity.Herein,the abilities of BiVO4,Ag-BiVO4,Ag2O-BiVO4 and Ag/Ag2O-BiVO4 to photocatalytically degrade MC-RR under visible-light irradiation（λ≥420 nm） were investigated and compared.The possible degradation pathways were explored through analysis of the reaction intermediates by high-performance liquid chromatography-mass spectrometry.The results showed that the presence of Ag^0 enhanced the photocatalytic efficiency of Ag/Ag2O-BiVO4 via a synergetic effect between Ag2O and Ag^0 at the p-n heterojunction.Moreover,the presence of Ag^0 also greatly promoted the adsorption of MC-RR on the photocatalyst surface.Toxicological experiments on mice showed that the toxicity of MC-RR was significantly reduced after photocatalytic degradation.

Ternary Ag/AgCl/BiOIO_3 composites for enhanced visible-light-driven photocatalysis

Ternary Ag/AgC l/BiO IO3 composite photocatalysts are prepared by a facile method. Enhanced visible-light absorption and charge carrier separation are achieved after the introduction of Ag/AgC l particles into BiO IO3 systems,as revealed by ultraviolet-visible diffuse-reflectance spectrometry,photocurrent response and electrochemical impedance spectroscopy. The Ag/AgC l/BiO IO3 composites are applied to the visible-light photocatalytic oxidization of NO in air and exhibit an enhanced activity for NO removal in comparison with Ag/AgC l and pure BiO IO3. A possible photocatalytic mechanism for Ag/AgC l/BiO IO3 is proposed,which is related to the surface plasmon resonance effects of Ag metal and the effective carrier separation ability of BiO IO3. This work provides insight into the design and preparation of BiO IO3-based materials with enhanced visible-light photocatalysis ability.

Facile synthesis of Ag_2O-TiO_2/sepiolite composites with enhanced visible-light photocatalytic properties

Ag2O-TiO 2/sepiolite heterostructure composites were synthesized by a simple two-step method at low temperatures（100–450 °C）. Acid red G aqueous solution and gaseous formaldehyde were chosen as model organic pollutants to evaluate the photocatalytic performance of the as-prepared composites. The results showed that the Ag2O-TiO 2/sepiolite exhibited enhanced photocatalytic activity over pure Ag2O-TiO 2,TiO 2/sepiolite,and Ag2O/sepiolite under visible-light irradiation（λ 420 nm）. The excellent photocatalytic efficiency of these composites can be ascribed to the synergistic effect between the heterojunction and the porous structure of the clay layers,which induced high adsorption and efficient charge separation. In addition,the active species involved in the degradation reaction have been investigated by photoluminescence spectroscopy and quenching experiments. A possible photocatalytic degradation mechanism of acid red G dye by the Ag2O-TiO 2/sepiolite composite is also discussed.

Sonochemical fabrication,characterization and enhanced photocatalytic performance of Ag_2S/Ag_2WO_4 composite microrods

Ag2S/Ag2WO4 composite microrods,with lengths of 0.2-1μm and diameters of 20-30 nm,were fabricated by a facile sonochemical route.The as-synthesized products were intensively investigated by a series of physicochemical characterizations,such as N2 physical adsorption,X-ray diffraction,scanning electron microscopy,transmission electron microscopy,Fourier transform infrared spectroscopy,diffuser reflectance spectroscopy,X-ray photoelectron spectroscopy,photoluminescence spectroscopy and photocurrent response measurements.Ultrasonic irradiation yields an obvious improvement in the photocatalyst texture,for example,an increase in crystallinity and surface area.Moreover,sonochemically fabricated Ag2S/Ag2WO4 microrods display strong visible light absorption and a high transient photocurrent response.The produced intimate Ag2S/Ag2WO4interface between Ag2S and Ag2WO4 crystal phases largely promotes the separation of photogenerated holes and electrons.High photocatalytic activity and stability were obtained over Ag2S/Ag2WO4composite microrods.The dye degradation rate constant of Ag2S/Ag2WO4 was 4.7 times and 29.8times higher than that of bare Ag2WO4 and Ag2S,respectively.

Facile template-induced synthesis of Ag-modified TiO_2 hollow octahedra with high photocatalytic activity

Noble metal/titania hollow nanomaterials usually exhibit excellent photocatalytic activity because of their high specific surface area,low density,good surface permeability,strong light-harvesting capacity,and rapid interfacial charge transfer. However,the present preparation methods usually include complicated and multistep procedures,which can cause damage to the hollow nanostructures. In this paper,a facile template-induced synthesis,based on a template-directed deposition and in situ template-sacrificial dissolution,was employed to prepare Ag-modified TiO 2（Ag/TiO 2） hollow octahedra using Ag2 O octahedra as templates and TiF 4 as the precursor. In the synthetic strategy,the shells of TiO 2 hollow octahedra were formed by coating TiO 2 nanoparticles on the surface of Ag2 O templates based on the template-directed deposition. Simultaneously,the Ag2 O templates can be in situ removed by dissolving the Ag2 O octahedral template in HF solution produced via the hydrolysis reaction of TiF 4 in the reaction system. In addition,Ag nanoparticles were deposited on the inside and outside surfaces of TiO 2 shells by effectively using the photosensitive properties of Ag2 O and Ag＋ ions under light irradiation,along with the formation of TiO 2 hollow octahedra. The Ag/TiO 2 hollow octahedra exhibited high photocatalytic activity because of their（1） short diffusion distances between photogenerated electrons and holes because of the thin shells of Ag/TiO 2 hollow octahedral,（2） deposition of Ag nanoparticles on the inside and outside surfaces of TiO 2 shells,and（3） rapid interfacial charge transfer between TiO 2 shells and Ag nanoparticles. This work may also provide new insights into preparing other Ag-modified and hollow nanostructured photocatalysts.

Catalytic performance of Ag/Co-Ce composite oxides during soot combustion in O_2 and NO_x:Insights into the effects of silver

The composite oxides xAg/Co_（0.93）Ce_（0.07）（x=Ag/（Co＋Ce） molar ratio）,intended for use as high performance catalytic materials,were successfully prepared via citric acid complexation.The effects of silver on the performance of these substances during soot combustion were subsequently investigated.Under O_2,the 0.3Ag/Co_（0.93）Ce_（0.07） catalyst resulted in the lowest ignition temperature,T_（10）,of197 ℃,while the minimum light-off temperature was obtained from both 0.2Ag/Co_（0.93）Ce_（0.07） and0.3Ag/Co_（0.93）Ce_（0.07） in the NO_x atmosphere.These materials were also characterized by various techniques,including H_2,soot and NO_x temperature programmed reduction,X-ray diffraction,and electron paramagnetic resonance,Raman,X-ray photoelectron,and Fourier transform infrared spectroscopic analyses.The results demonstrated that silver significantly alters the catalytic behavior under both O_2 and NO_x,even though the lattice structure of the mixed oxide is not affected.Surface silver oxides generated under the O_2 atmosphere favor soot combustion by participating in the redox cycles between soot and the silver oxide,whereas the AgNO_3 that forms in a NO_x-rich atmosphere facilitates soot abatement at a lower temperature.The inferior activity of AgNO_3 relative to that of Ag_2O results in the different catalytic performance in the presence of NO_x or O_2.

Effect of preparation routes on activity of Ag-MnO_x/C as electrocatalysts for oxygen reduction reaction in alkaline media

The effect of preparation routes on the physical characteristics and activity of the Ag-MnOx/C composites toward the oxygen reduction reaction （ORR） in alkaline media were studied by X-ray diffraction （XRD）, X-ray photoelectron spectroscopy （XPS）, transmission electron microscopy （TEM）, energy-dispersion spectroscopy （EDS） as well as scanning electron microscopy （SEM） and electrochemical techniques. The results show that more Ag and Mn species present on the surface of the Ag-MnOx/C composite prepared by two-step route （Ag-MnOx/C-2） compared to the one prepared by one-step route （Ag-MnOx/C-1）, which contributes to its superior activity toward the ORR. The higher electron transfer number involved in the ORR can be observed on the Ag-MnOx/C-2 composite and its specific mass kinetic current at -0.6 V （vs Hg/HgO） is 46 mA/μg, which is 23 times that on the Ag/C. The peak power density of zinc-air battery with the Ag-MnOx/C-2 air electrode reaches up to 117 mW/cm^2.

NO reduction by CO over TiO_2-γ-Al_2O_3 supported In/Ag catalyst under lean burn conditions

TiO2/γ-Al2O3 supported In/Ag catalysts were prepared by impregnation method,and investigated for NO reduction with CO as the reducing agent under lean burn conditions.The microscopic structure and surface properties of the catalysts were studied by N2 adsorption-desorption,X-ray diffraction,transmission electron microscopy,X-ray photoelectron spectroscopy,ultraviolet-visible spectroscopy,H2 temperature-programmed reduction and Fourier transform infrared spectroscopy.TiO2/γ-Al2O3 supported In/Ag is a good catalyst for the reduction of NO to N2.It displayed high dispersion,large amounts of surface active components and high NO adsorption capacity,which gave good catalytic performance and stability for the reduction of NO with CO under lean burn conditions.The silver species stabilized and improved the dispersion of the indium species.The introduction of TiO2 into the γ-Al2O3 support promoted NO adsorption and improved the dispersion of the indium species and silver species.