‘鸭梨’、‘新高’果实发育过程中果肉及种子有机酸含量的变化

为了研究梨种子对果实生长发育的影响,采用高效液相色谱(HPLC)技术对‘鸭梨’和‘新高’果实发育过程中果肉和种子中的有机酸含量进行了分析。结果表明：两个品种果肉中主要的有机酸组分均为苹果酸和奎尼酸,发育初期‘鸭梨’与‘新高’果肉中各组分的比率相近,但果实成熟时‘新高’果肉中苹果酸的比率59.98%显著高于‘鸭梨’的37.51%；两个品种种子中的有机酸组分比率的动态变化相近,与果肉相反,主要表现在奎尼酸比率的增加和苹果酸比率的减少。两个品种果肉和种子中的总酸、草酸、奎尼酸,苹果酸,莽草酸,柠檬酸含量均随着果实的成熟呈下降趋势,‘鸭梨’果肉中的奎尼酸、莽草酸、柠檬酸含量高于‘新高’；‘新高’在果实成熟时种子中的总酸含量4.59mg/g显著低于‘鸭梨’13.00mg/g,‘鸭梨’成熟果实种子中的草酸、奎尼酸、莽草酸含量显著高于‘新高’；在果实发育初期,种子中的苹果酸含量极显著高于果肉,在果实成熟时则显著低于果肉。     

ECMWF细网格对浙江沿海10 m风预报性能评估

为更好地开展浙江沿海海上大风的预报服务,本研究对2012年1月1日—2014年12月31日的ECMWF细网格10 m风场产品在浙江沿海的预报性能进行评估,并将其插值到沿海站点和观测数据进行对比分析。结果表明:冷空气影响下,浙江沿海的平均误差为负值,绝对误差分布和变化趋势与平均误差基本一致;台风影响下,24 h预报时效的平均误差为正值,随着预报时效的增加,平均误差逐渐转为负值,鱼山渔场、温台渔场及舟外渔场的绝对误差较其他区域大。另外,预报值和观测数据间的相关系数随预报时效的增加而减小,两者之间的相关系数平均值随海拔高度的增加而减小;ECMWF细网格对岱山和龙山村的预报偏大,对浪岗的预报偏小,预报偏差的离散度随预报时效增加而增大。     

基于DEB理论的皱纹盘鲍个体生长模型参数的测定

为获取皱纹盘鲍(Haliotis discus hannai)个体生长模型所需的6个关键参数，设计了饥饿耗能、温度对耗氧的影响等相关生理实验，计算得到各项参数值。单位体积维持耗能率的值 、形成单位体积结构物质所需的能量值 、单位体积最大储存能量 和储备能量值 4个参数，通过连续测定皱纹盘鲍饥饿过程中呼吸耗氧率和软组织干重不断下降直至保持稳定时的能量值计算；温度函数中Arrhenius温度 的数值根据皱纹盘鲍在不同温度梯度下的单位干重耗氧率测定、计算；形状系数δm值通过统计测量的壳长、软组织湿重等生物学参数拟合回归得到。结果显示，皱纹盘鲍在饥饿后，呼吸耗氧率和软组织干重分别降低了26.3%和70.0%，呼吸耗氧率由2.69 mg/(ind.?h)逐渐降低并稳定在0.8 mg/(ind.?h)，软组织干重由(5.21±0.89) g降低至(3.84±0.22) g；根据公式计算得 和 的值分别为20.18 J/(cm3?d)和8120 J/cm；皱纹盘鲍饥饿前后有机物含量分别为80%和58%，经过换算， 和 的值分别为2726 J/cm3和32583 J/g。不同规格的皱纹盘鲍在水温为5℃~20℃范围内，温度与单位干重耗氧率呈正比；当水温超过20℃之后，温度与单位干重耗氧率呈反比。在转折点20℃之前，单位干重耗氧率的ln值与温度(热力学温度，K)的倒数呈线性关系，线性回归方程斜率的绝对值为Arrhenius温度 值( =7196 K)。生物学统计分析鲍壳长(L)与体积(V)呈三次函数关系：V=0.0639 L3.1621(R²=0.9852)，根据公式对软组织湿重的立方根与壳长进行线性回归，所得的斜率即为形状系数δm值(δm=0.43)。本研究对建立以DEB理论为指导的皱纹盘鲍个体生长模型提供了数据支撑。     

Gymnastic Training of Hippotherapy Horses Benefits Gait Quality When Ridden by Riders with Different Body Weights

The objective was to evaluate the effects of gymnastic training on stride characteristics of walk and trot in therapy horses carrying riders of different weights. Eighteen horses used for therapeutic riding 5 days/week were randomly divided into 2 groups. Nine horses performed gymnastic (GYM) exercises after therapeutic riding on 4 days/week for 3 months, 9 horses did no additional exercises (SED). On days 0 and 90, an inertial sensor mounted to the girth on the ventral midline was used to evaluate stride characteristics when horses were ridden at walk (1.3 m/second) and trot (3.0 m/second) by able-bodied riders representing rider: horse body weight ratios (BWRs) 15%, 20%, and 25%. On day 0, the measured variables did not differ significantly between sedentary (SED) and GYM groups, but on day 90, the following statistically significant results were found: GYM-trained horses had higher regularity for all BWRs at walk and 15% and 20% BWRs at trot. Higher stride symmetry was found in GYM-trained horses carrying 25% BWRs at walk and all rider weights at trot. Dorsoventral displacement was higher in GYM-trained horses when carrying 20% and 25% BWRs at walk and 25% BWRs at trot. Dorsoventral power was lower in SED-trained versus GYM-trained horses carrying 15% BWR at walk and 20% BWR at trot. A more regular and symmetrical stride with a larger range of dorsoventral trunk motion is likely to provide a better therapeutic riding experience.     

玉米果穗不同部位子粒水分动态差异研究

为明确玉米果穗不同部位子粒含水率和脱水速率的动态变化差异,在春玉米区宁夏银川和夏玉米区河南新乡采用8个不同熟期和脱水速率的品种,将玉米果穗垂直等分为5个部位,定期测定不同部位子粒含水率,计算子粒脱水速率。结果表明,玉米生长中后期,果穗上部子粒含水率低于中下部子粒含水率,生理成熟前各部位子粒含水率的差值低于生理成熟后。参试品种生理成熟前20 d时不同部位子粒含水率极差低于3%,成熟期的极差值变幅为0.6%～5.2%,生理成熟后极差最大值可达6.2%。同一果穗自上而下子粒的脱水速率逐渐降低,品种之间有明显差异,先玉335、迪卡517和迪卡519果穗不同部位子粒脱水速率差异较大。果穗中部子粒脱水速率和平均脱水速率与不同部位子粒含水率的极差值呈负相关。     

基于森林资源调查的北京西山油松人工林生物量动态变化研究

基于森林资源调查数据分析西山林场油松人工林生物量多年动态变化情况,结果表明:2004-2014年,油松人工林以近熟林和成熟林为主,成熟林面积和生物量大幅增长,幼龄林、中龄林、近熟林面积和生物量明显减少,单位面积生物量及生产力最高的立地类型为低阴中松,单位面积生物量按大小排序:阔叶混交林>针阔混交林>针叶混交林>针叶纯林。     

燃烧室与油束匹配的动态计算

介绍了一种燃烧室与油束匹配的动态计算方法和计算过程,通过计算可以保证在整个供油持续期内燃油喷射在燃烧室内特定的区域,避免喷射到活塞顶部和燃烧室底部,确保油、气的充分均匀混合,避免因燃油喷射到活塞顶部和燃烧室底部而引起的燃烧不充分,从而造成油耗的升高和颗粒排放的增加。针对一种欧Ⅳ排放的四缸柴油机进行了计算验证。     

机械传动系统扭矩及功率的动态测试（一）

针对目前林木及运输机械传递扭矩估算与实测值(均值)相差悬殊，本从实时检测动态扭矩及功率入手，提出中低速大扭矩及功率的数据采集方法。     

DETERMINATION OF STATIC AND DYNAMIC DIFFUSION COEFFICIENTS OF MOISTURE IN PARTICLEBOARDS

The static and dynamic diffusion coefficients are important coefficients todescribe the moisture transfer processes in particleboard.In this paper,the formula ofculculating the static and dynamic diffusion coefficients were deduced.At first,the staticdiffusion coefficients of four kinds of particleboards were determined by using diffusion cupmethod.The results demonstrated that the static diffusion coefficients parallel to panelsurface were 10-20 times as large as that of perpendicular to panel surface for test boards.To determine both dynamic diffusion coefficients and surface emission coefficients ofmoisture in particleboards in one experimental period,specimens in four different thickness-es of each kind of particleboard were used in the experiment.Then the method ofregression was used and the dynamic diffusion coefficients and surface emission coefficien-ts were determined based on the slope and intercept of the regressive line.     

A Danish example of optimal thinning strategies in mixed-species forest under changing growth conditions caused by climate change

In this study, we analyse the economic and managerial aspects of option values related to having a mixed-species stand. As an example, we look at a mixed Norway spruce and Sitka spruce stand in Denmark when timing and intensity of future climate, and its effect on tree growth, are uncertain. Assuming that tree growth follows a discrete non-stationary stochastic process, we use dynamic programming to optimise the harvest distribution between the two species.

The results show that facing growth uncertainty caused by potential climate change implies an option value. Such uncertainty can be a potential advantage as long as we are able to maintain flexibility, keep decisions open, and there is a chance that climatic change will benefit some species. We analyse the model under different uncertainty assumptions and show that the larger changes we expect, the higher is the option value at any time during the stand’s life and, hence, we keep, on average, both tree species in the stand for a longer period of time. Moreover, we find that the adjustments may take place rather late in the rotation, a result brought about by the significance of the option value, which makes it optimal to maintain a reasonable stocking of both species.