智能着水与压力控制精米抛光机的研制

根据大型化碾米工艺要求而研发的智能着水与抛光室压力控制的新型精米抛光机，集成应用机电气液及计算机技术，实现了精米抛光作业的高效、优质和低耗。所采用的分段式主抛和精抛流程的组合既有利于获得最佳的抛光效果，又提高了设备对原粮品种的适应性；系统设计中运用的机外着水及智能化着水量控制方案使水分的设定和控制可以根据进出机白米的状态达到最优化；具有独特构造的水、料混合装置，避免了传统螺旋混料器对白米的增碎作用，同时可以强化水、料之间的传质与传湿过程；抛光室压力的模糊自动控制的实现进一步提升了设备的性能和适用范围；喷风、补风和吸风结合的风系设计保证了低温升抛光条件，有利于保护大米表面。MPG21/18抛光机经生产考核其作业质量较高，可以满足现代精碾碾米工业的装备需求。     

“Fertile island” effects of <Emphasis Type="Italic">Tamarix chinensis</Emphasis> Lour. on soil N and P stoichiometry in the coastal wetland of Laizhou Bay,China

Purpose

As a useful comprehensive index for reflecting nutrient cycling in soils, nitrogen (N) and phosphorus (P) stoichiometry is subject to influences of many external environmental and biological factors. Studies on such influences were limited, and the influential mechanism remains unclear. The purpose of this research is to investigate soil N and P stoichiometric variations and analyze “fertile island” effects of Tamarix chinensis Lour. (T. chinensis) in the coastal wetland of Laizhou Bay in China.

Materials and methods

Soil samples beneath clusters and communities of T. chinensis were collected respectively in July 2012. Amounts of ammonium, nitrate, and available phosphorus in the soil samples were measured through the corresponding standard methods for material measuring.

Results and discussion

In general, there were significant vertical variations in soil N and P stoichiometry beneath clusters and communities of T. chinensis. A downtrend was observed for N and P contents with the increase in soil depth. On the contrary, the N/P ratio revealed a trend of going up first and then dropping off along with the increase of the soil depth. Comparatively, the horizontal variations in the soil N and P stoichiometry beneath a single cluster of T. chinensis were greater in the topsoil than those in the subsoil. The N and P contents gradually decreased from the canopy center to the outside. On the contrary, an opposite trend was found for the N/P ratio. For the horizontal variations beneath T. chinensis communities, there were no significant differences for either N and P contents or N/P ratios.

Conclusions

Similar to the ecosystems in arid and semi-arid areas, vegetations in many semi-humid areas could also form fertile islands and exert significant influences on the soil nutrient cycle. The formation of fertile islands beneath a single cluster of T. chinensis could have significant influence on soil N and P stoichiometry. Under the influence of fertile islands beneath T. chinensis, the limiting element of the biogeochemical processes in the coastal wetland of Laizhou Bay might change from N to P. However, the influences of fertile island effects on soil N and P stoichiometry beneath T. chinensis communities were relatively small, illustrating that the influences of fertile island effects was not significant at the community level. Thus, the impacts of environmental factors on soil N and P stoichiometry might be greater than that of the fertile island effects in the wetland on a larger scale.

     

土壤微生物生态学在农业中的应用研究综述

土壤微生物生态学是陆地生态系统研究中最重要的组成部分,是土壤学、微生物学和生态学相互渗透、相互结合的一门新兴学科。本文从研究方法、农业施肥、农业种植制度、生态防治及应用展望等方面对土壤微生物生态学的应用研究现状作了综述,加强土壤微生物生态学在农作物生长和调控应用等领域的研究具有巨大的潜在应用前景和重要意义。     

能源与生态经济建设

21世纪是生态经济建设时代，资源的过度消耗是生态经济建设的致命问题，农村可再生能源开发是保护生态资源的有效手段。该文从社会经济系统和自然生态系统物质和能量的供求关系入手，结合农村可再生能源建设实践，依据生态经济学的基本原理，论证了农村可再生能源开发在生态经济建设中的作用，提出了农村可再生能源建设的设想。     

青藏高原农田生态系统碳平衡

为探讨青藏高原农田生态系统碳平衡规律及其影响因子 ,并揭示其对全球含碳温室气体源、汇变化的贡献与响应 ,1 998～ 1 999连续 2年在拉萨农业生态站农田用静态箱法和生物量取样法开展土壤—植被界面CO2 吸收与排放的试验研究。农作物生长季 ,以冬小麦为例 ,生长前期 (从播种到拔节 )土壤碳排放量高于植被碳固定 ,生长后期 (灌浆到成熟 )则是植被碳固定高于土壤碳排放量 ,从全年来看 ,土壤碳排放量略高于植被碳固定     

A Novel High Capacity Biofilm Reactor System for Treatment of Domestic Sewage

A lab-scale novel biofilm reactor system, Ultra-Compact Biofilm Reactor (UCBR), was studied to investigate its performance and operational characteristics for domestic sewage treatment. The reactor was operated at four different hydraulic retention times, namely, 90, 60, 30 and 15 min. The operating ranges of volumetric loading rates in terms of COD, BOD₅, NH⁺ ₄-N and TKN were 5.6-62.1 kg COD/m³ d, 2.6-32.5 BOD₅/m³ d, 0.6-3.2 kg NH⁺ ₄-N/m³ d and 0.82-6.2 kg TKN/m³ d, respectively. The COD, BOD₅ and NH⁺ ₄-N removal efficiencies at 90-min hydraulic retention time (HRT) and 60-min HRT could exceed 80%, 90% and 99%, respectively. The corresponding maximum biomass concentrations were 12.0 g/L and 15.0 g/L at 90-min HRT and 60-min HRT, respectively. At 30-min HRT, the biomass concentration increased to a maximum of 24.0 g/L. However, COD and BOD₅ removal efficiencies decreased to 75% and 80%, respectively, while the NH⁺ ₄-N nitrification efficiency decreased to only 25% to 30%. These observations suggested that high biomass concentration alone was not sufficient to provide a high removal capacity in a UCBR. Further reduction in HRT to 15 min led to an excessive biomass decline from 22.5 g/L to 4.0 g/L. On the whole, the UCBR was able to sustain COD removal and NH⁺ ₄-N conversion of up to 5.96-18.70 kg COD/m³ d and 0.73-1.00 kg NH⁺ ₄-N/m³ d, respectively.     

近红外光谱分析法测定菜籽油中芥酸的含量

采用多通道PDA型近红外光谱仪，应用偏最小二乘法建立了菜籽油中芥酸含量与近红外透射光谱的校正模型，讨论多项式求导及平滑的窗口宽度和相关系数法筛选有效波长对校正模型的影响，并对10个预测集样品利用预测相关系数R_p和预测均方根误差RMSEP指标进行了预测精度分析，结果发现：在使用全谱数据进行偏最小二乘回归建模时，一阶7点求导及平滑的预处理方法结果最佳，此时建模效果为：R_p=0.739，RMSEP=1.659；在此基础上通过相关系数法筛选波长后的建模效果为：R_p=0.958，RMSEP=0.963。后者R_p提高29%，RMSEP减少42%。由此可得出多项式求导及平滑法和相关系数法相结合对校正模型稳健性，预测精度都有较大提高的结论。研究证明：多通道近红外光谱仪快速测测菜籽油中芥酸含量的方法是可行的。     

植保四轴飞行器的模糊PID控制

针对当前植保四轴飞行器在作业过程中自身载荷发生改变后的飞行控制性能下降、抵抗环境扰动能力差的问题,该文改进了传统比例积分微分(proportion,integration,differentiation,PID)控制算法,提出了一种模糊PID控制算法。该文通过研究四轴飞行器的姿态解算和飞行原理,设计了以STM32系列的单片机为核心处理器的四轴飞行控制系统。采用AHRS模块实时解算飞行器姿态参数,结合模糊控制和PID控制算法调节电机的输出量来控制飞行姿态。试验结果表明:与传统PID相比,模糊自整定PID控制算法适应性强,参数整定简单,系统的动态响应能力和稳定性获得了提高,实现了四轴飞行器的稳定飞行。该文为植保无人机控制算法研究提供了一定的参考。     

土壤全量N、P、K试样联合消解方法研究

十九世纪末叶,J. Kjedahl, J. lawrence Smith等相继提出了土壤全量N. P. K的分析方法。百余年来其分析,检测技术虽然发展较快,但上述三元素试样的熔融和消煮等所需的时间与最后检测所需时间之比,仍为5:1至20:1,耗时甚多。况且尚无三元素一次性联合消解方法和仪器,严重影响了分析速度^[1,4-6]。经多年实验研究,我们提出了在80-260℃条件下土壤全量N. P. K试样一次性联合消解的原理、方法和仪器,均取得了满意的结果。