温度对牙鲆幼鱼消化率日变化和生长的影响

研究了不同温度(18、23、28℃)对牙鲆Paralichthys olivaceus幼鱼(4.25 g±0.19 g)消化率日变化和生长的影响。结果表明:(1)摄食率随温度的升高有增加的趋势,但各组之间的差异均不显著(P>0.05);特定生长率随温度上升显著提高(P<0.05),饲料转化率和蛋白质效率均先增大后减小,但各组之间的差异均不显著(P>0.05);(2)18℃组、23℃组和28℃组牙鲆幼鱼的干物质表观消化率(Ddm)日变化分别为64.91%~80.84%、62.05%~82.78%和69.76%~81.69%,日变化表现为1~2 d的高消化率,之后有1~2 d的低消化率;(3)18℃组、23℃组和28℃组牙鲆幼鱼的蛋白质表观消化率(Dp)日变化分别为89.38%~93.39%、87.86%~93.82%和88.25%~93.34%,日变化表现为1~3 d的高消化率,之后有1~3 d的低消化率;(4)随温度的升高,牙鲆幼鱼的平均干物质表观消化率与平均蛋白质表观消化率均没有显著变化(P>0.05);(5)随着温度的升高,牙鲆幼鱼体水分含量显著下降(P<0.05),粗脂肪含量显著提高(P<0.05),粗...     

吉林省森林火灾释放碳量的时间变化规律

根据吉林省1969-2004年的森林火灾统计数据,计算出吉林省森林火灾年均释放碳22004.38～29339.17t,约占全国年均森林火灾排放碳的1.05%.用排放比法得出吉林省年平均森林火灾释放的CO2、CO、CH4量分别为72614.45～96819.27、5283.01～7044.02和1784.40～2379.20t.吉林省森林火灾碳和含碳气体释放最多的月份是9月,占总释放量的60.6%,其次为10、5和4月,分别占总释放量的16.1%、11.4%和9.8%.吉林省森林火灾碳和含碳气体释放最多的时间段是13:00-13:59,占总释放量的31.4%,其次是14:00-14:59、15:00-15:59和11:00-11:59,分别占总释放量的18.7%、16.4%和16.0%.     

泥鳅消化道6种内分泌细胞的免疫组织化学定位

1材料与方法 1．1材料泥鳅4尾,雌雄各半,2007年5月购自安徽省芜湖吉合菜市场。置于清水中暂养24h后迅速解剖,按下列消化道各段取材：食道、前肠前段、前肠后段、中肠、后肠前段、直肠。生理盐水洗净,用无冰醋酸的Bouin氏液固定18—24h,常规脱水透明,石蜡包埋,切片5～6μm,贴片,37℃温箱烘干备用。     

黑龙江水稻灌浆特性及其应用研究

[目的]研究黑龙江水稻灌浆特性。[方法]建立水稻灌浆过程的数学模式,着重研究水稻灌浆与气温的关系。[结果]结果表明,该模式反映了正常条件下水稻灌浆的生物学规律。[结论]该研究结果为选择水稻品种、栽培管理及产量预报提供指导。     

基于单片机与串行通信的电子密码锁设计

 基于AT89C52单片机,在异步串行通信总线上实现分组交换通信协议的电子密码锁的软硬件设计方法,经实验室小范围内测试,可实现按键输入、校验与报警等功能。该密码锁防嗅探,外围元件少,结构简洁,可单机或联网使用。     

短角异剑水蚤胚胎发育和幼体发育的研究

研究了短角异剑水蚤Apocyclops royi的胚胎和胚后发育过程.结果表明:短角异剑水蚤在盐度为34±1,温度为(24±1)℃的情况下,胚胎发育的时间为40～45 h,无节幼体发育时间为3.5～4 d,桡足幼体的发育时间为5～6 d,从受精卵到发育为成体累计需要11～12 d.短角异剑水蚤雌体在交配后可连续挂卵,并孵化出多胎幼体而无需再次受精.无节幼体孵出3～4 h内即可摄食.     

刺鲃的生物学研究

对刺鲃的生物学进行了研究,结果表明：刺鲃的可数性状比较稳定。体长与体重的回归关系式为W=0.0279L^2.919。肠长为体长的2.3倍,食性为偏肉食的杂食性,主要摄食螺、虾、水生昆虫及其幼虫。雌鱼的性成熟年龄为3龄,绝对怀卵量为35928-46589粒/尾,分批产卵类型,卵为弱粘性卵,产卵期为5-6月份。雄鱼的性成熟年龄为2龄。     

长期免耕对东北地区玉米田土壤有机碳组分的影响

Increasing evidence has shown that conservation tillage is an effective agricultural practice to increase carbon (C) sequestration in soils. In order to understand the mechanisms underlying the responses of soil organic carbon (SOC) to tillage regimes, physical fractionation techniques were employed to evaluate the effect of long-term no-tillage (NT) on soil aggregation and SOC fractions. Results showed that NT increased the concentration of total SOC by 18.1% compared with conventional tillage (CT) under a long-term maize (Zea mays L.) cropping system in Northeast China. The proportion of soil large macroaggregates ( 2000 μm) was higher in NT than that in CT, while small macroaggregates (250-2000 μm) showed an opposite trend. Therefore, the total proportion of macroaggregates ( 2000 and 250-2000 μm) was not affected by tillage management. However, C concentrations of macroaggregates on a whole soil basis were higher under NT relative to CT, indicating that both the amount of aggregation and aggregate turnover affected C stabilization. Carbon concentrations of intra-aggregate particulate organic matter associated with microaggregates (iPOM m) and microaggregates occluded within macroaggregates (iPOM mM) in NT were 1.6 and 1.8 times greater than those in CT, respectively. Carbon proportions of iPOM m and iPOM mM in the total SOC increased from 5.4% and 6.3% in CT to 7.2% and 9.7% in NT, respectively. Furthermore, the difference in the microaggregate protected C (i.e., iPOM m and iPOM mM) between NT and CT could explain 45.4% of the difference in the whole SOC. The above results indicate that NT stimulates C accumulation within microaggregates which then are further acted upon in the soil to form macroaggregates. The shift of SOC within microaggregates is beneficial for long-term C sequestration in soil. We also corroborate that the microaggregate protected C is useful as a pool for assessing the impact of tillage management on SOC storage.     

酶法辅助提取柑桔皮总黄酮的工艺优化研究

为了充分利用农业废弃物柑桔皮,进一步提高柑桔皮中总黄酮的提取效率,在单因素试验的基础上,采用中心组合设计对柑桔皮总黄酮纤维素酶法辅助提取工艺中的提取时间、提取温度、pH值和酶用量4因子的最优化组合进行了定量研究,建立并分析了各因子与黄酮得率关系的数学模型.结果表明:最佳的工艺条件为酶用量0.55%、提取时间123 min、pH值4.4、温度48℃.经试验验证,在此条件下,黄酮得率为(3.51±0.13)%,与理论计算值3.62%基本一致.说明回归模型能较好地预测柑桔皮中总黄酮的提取得率.     

Solvent-free enzymatic preparation of feruloylated monoacylglycerols optimized by response surface methodology

The ability of immobilized lipase B from Candida antarctica (Novozym 435) to catalyze the direct esterification of glyceryl ferulate (FG) and oleic acid for feruloylated monoacylglycerols (FMAG) preparation in a solvent-free system was investigated. Enzyme screening and the effect of glycerol on the initial reaction rate of esterification were also investigated. Response surface methodology (RSM) was used to optimize the effects of the reaction temperature (55-65 degrees C), the enzyme load (8-14%; relative to the weight of total substrates), oleic acid/(FG + glycerol) (6:1-9:1; w/w), and the reaction time (1-2 h) on the conversion of FG and yield of FMAG. Validation of the RSM model was verified by the good agreement between the experimental and the predicted values of FG conversion and FMAG yield. The optimum preparation conditions were as follows: temperature, 60 degrees C; enzyme load, 8.2%; substrate ratio, 8.65:1 (oleic acid/(FG + glycerol), w/w); and reaction time, 1.8 h. Under these conditions, the conversion of FG and yield of FMAG are 96.7 +/- 1.0% and 87.6 +/- 1.2%, respectively.