TCD燃烧系统对柴油机燃烧和排放性能改善效果的试验研究

为探究道依茨TCD2015柴油机上配备的导流燃烧系统(简称TCD燃烧系统,T表示涡轮增压器,Turbocharger,C表示进气中冷,Charge air cooling,D为柴油颗粒捕集器,Diesel particle filter)对改善柴油机燃烧性能和降低污染物排放的效果,采用单缸机试验对TCD燃烧系统在不同转速、负荷和过量空气系数下的燃烧和排放性能进行研究。试验结果表明不同工况下TCD燃烧系统燃油消耗率和Soot排放量均低于传统ω燃烧系统,燃油消耗率最大降幅为7.01%,Soot排放量最大降幅为86.67%,且低过量空气系数(1.2～1.6)下TCD燃烧系统仍具有较好的性能。为揭示TCD燃烧系统改善油气混合促进燃烧的机理,采用AVL Fire软件建立了柴油机性能仿真模型。计算结果表明,TCD燃烧系统的环状凸起结构将燃油导向内外两室,从而促进了缸内燃油发展过程,燃油当量比大于4的浓混合气区域燃油质量比例相比ω燃烧系统降幅最大为9.75%,活塞下移时TCD燃烧系统内油束撞击浅盘侧壁形成撞壁射流扩大了燃油扩散面积,从而改善了缸内油气混合质量,燃油当量比小于1的均匀混合气区域燃油质量比例相比ω燃烧系统降幅最大为7.45%,因此TCD燃烧系统能够有效改善柴油机的燃烧和排放性能,可应用于柴油机高负荷和低过量空气系数工况综合性能提升。研究结果可为柴油机燃烧系统开发和改进提供参考。     

Effect of dietary phosphorus levels on growth and body composition of crucian carp,Carassius auratus under indoor and outdoor experiments

Indoor and outdoor experiments were carried out simultaneously to evaluate the effects of dietary phosphorus levels on growth performance and body composition of crucian carp. Monocalcium was used to formulate extruded feed containing available phosphorus (AP) of 1.5 (D1), 4.7 (D2), 6.3 (D3) and 9.0 (D4) g kg^?1. Twelve 500‐L recirculating tanks were assigned to four triplicate groups with each tank stocked with 15 juveniles (39.88 ± 0.14 g) for indoor experiment. Twelve polyethylene enclosures were assigned to four groups with each one stocked with 120 juveniles (44.08 ± 1.36 g). After 8 weeks of feeding, survival ranged from 96% to 100%. Weight gain, special growth rate, protein efficiency ratio and feed conversion rate did not show significant differences among dietary treatments in both experiments. Fish cultured in the enclosures grew better, although D1 and D2 treatments did not reach significant level. Crude protein and phosphorus content of the fish were not significantly affected by dietary phosphorus level. Moisture, crude lipid, crude ash and vertebrae phosphorus were significantly affected by different phosphorus levels. Based on vertebrae phosphorus, crucian carp cultured in the tanks and in the enclosures showed phosphorus deficiency under 4.7 g kg^?1 and 6.3 g kg^?1 AP, respectively.     

Novel soil quality indicators for the evaluation of agricultural management practices: a biological perspective

Developments in soil biology and in methods to characterize soil organic carbon can potentially deliver novel soil quality indicators that can help identify management practices able to sustain soil productivity and environmental resilience. This work aimed at synthesizing results regarding the suitability of a range of soil biological and biochemical properties as novel soil quality indicators for agricultural management. The soil properties, selected through a published literature review, comprised different labile organic carbon fractions [hydrophilic dissolved organic carbon, dissolved organic carbon, permanganate oxidizable carbon (POXC), hot water extractable carbon and particulate organic matter carbon], soil disease suppressiveness measured using a Pythium-Lepidium bioassay, nematode communities characterized by amplicon sequencing and qPCR, and microbial community level physiological profiling measured with MicroResp^TM. Prior studies tested the sensitivity of each of the novel indicators to tillage and organic matter addition in ten European long-term field experiments (LTEs) and assessed their relationships with pre-existing soil quality indicators of soil functioning. Here, the results of these previous studies are brought together and interpreted relative to each other and to the broader body of literature on soil quality assessment. Reduced tillage increased carbon availability, disease suppressiveness, nematode richness and diversity, the stability and maturity of the food web, and microbial activity and functional diversity. Organic matter addition played a weaker role in enhancing soil quality, possibly due to the range of composition of the organic matter inputs used in the LTEs. POXC was the indicator that discriminated best between soil management practices, followed by nematode indices based on functional characteristics. Structural equation modeling shows that POXC has a central role in nutrient retention/supply, carbon sequestration, biodiversity conservation, erosion control and disease regulation/suppression. The novel indicators proposed here have great potential to improve existing soil quality assessment schemes. Their feasibility of application is discussed and needs for future research are outlined.     

Harvesting machine for kelp culture in floating raft

Kelp is not only a kind of food of sea vegetable for human, but also widely used as raw materials in processing food, chemical engineering, pharmaceutical and cosmetic industries. In China kelp is generally planted on floating raft by using horizontal kelp rope cultivation method and often harvested manually. Harvesting kelp by hand is a difficult process with low production efficiency and high labor intensity. In this paper, a harvesting machine was developed for floating raft culture of kelp. It consists of mainly two locomotion modules, a collection/transmission module and a power module. The structure and working mechanism of this machine was presented and analyzed in detail. The tests of experiments were conducted as well with the developed machine. The manual harvest efficiency is 16.7%; however the mechanized harvest efficiency average value is 35.8%. The harvest time could be reduced by half if the company takes the same people to work. It is proven that the design of the machine is feasible.     

金针菇松杉木屑菌糠栽培猴头菇的技术研究

为降低猴头菇生产成本和解决松杉木屑工厂化栽培金针菇菌糠利用问题,研究了金针菇菌糠营养成分和不同配方对猴头菇产量及经济效益的影响。结果显示:金针菇菌糠含有9.8%粗蛋白、32.3%粗纤维、1.2%粗脂肪、17.9%木质素和7.7%灰分;筛选出配方2是最佳的配方,比例分别为金针菇菌糠38%、棉籽壳20%、玉米芯30%、麸皮10%、碳酸钙2%,其产量和利润分别比对照组、配方1、配方3和配方4提高了9.67%、25.00%、6.12%、8.40%和115.91%、48.44%、46.15%、25.00%。为金针菇菌糠用于猴头菇大面积栽培提供了科学依据。     

分段螺旋式甘草茎秆揉切装置设计与试验

针对全混合日粮饲草料揉切需求，该研究设计了一种分段螺旋式甘草茎秆揉切装置，对分段螺旋叶片的主体结构和搅龙结构参数进行设计，建立了刃口曲线方程，分析了装置揉切机理，并试制了分段螺旋式甘草茎秆揉切装置试验台。以搅龙转速、加工时间、填充系数、刀片与底壳间隙为因素，以粒度、破节率、单位质量能耗为指标，开展四因素三水平Box-Behnken试验，对试验结果进行方差分析和二次回归拟合，得出各因素对粒度影响显著性由大到小为加工时间、搅龙转速、填充系数、刀片与底壳间隙；对破节率的影响显著性由大到小为加工时间、填充系数、搅龙转速、刀片与底壳间隙；对单位质量能耗的影响显著性由大到小为填充系数、加工时间、搅龙转速、刀片与底壳间隙。对交互影响因素进行响应曲面分析并进行参数优化验证试验，结果表明：当搅龙转速为25 r/min、加工时间为12 min、填充系数为0.46、刀片与底壳间隙为15 mm时，甘草茎秆的揉切粉碎粒度为11.76 mm，破节率为83.27%，此时单位质量能耗为9 959.82 J/kg，试验值与模型理论值误差不超过7%，参数优化模型合理，满足作业要求。研究结果可为全混合日粮搅拌机的研发提供理论依据。     

不同激励下宽频磁浮俘能器俘能试验

振动能量俘获是获取可再生的清洁能源一种有效途径，具有广阔的应用前景，有利于社会的可持续性发展。目前，随机功率谱激励下的高功率密度和宽频能量回收仍然是研究的难点。该研究设计了一种可有效利用宽频振动能量的高功率密度磁浮式俘能器，采用COMSOL Multiphysics软件计算悬浮磁体非线性回复力与位移的关系式，根据磁浮振动系统的控制方程和基尔霍夫定律建立俘能器的数学模型，详细研究了模型参数变化对俘能器性能的影响。随后进行正弦扫频和驻频试验以验证俘能器的发电能力。同时，从俘能器的效率、效能和体积优质3个指标对俘能性能进行评价；并结合实际应用，设计俘能器稳压电路。根据丘陵山区农业机械工作的随机路谱特性，建立随机激励的数学模型，根据响应幅值的概率密度函数的FPK方程表达式，得到了平稳概率密度函数的解。结果表明：在激励频率从9.77到31.75 Hz变化时，俘能器最大输出电压在5.92和21.52 V之间；最大输出功率在10 Hz时达81.93 mW，从5到50Hz，输出功率范围为5.76到81.93 mW；俘能器的效率、效能和体积优质分别为2.85%，9.85%和39.74%；俘能器电压输出的功率谱密度有5个峰值点，对应频率分别为9.804、29.41、36.76、36.76、51.47和71.08 Hz，进一步验证了该研究提出的磁浮式俘能器具有宽频发电性能，并可满足丘陵山区农机设备监测传感器的供电需求。     

几个杨树新品系苗期耐盐碱试验

本文采用室外大花盆栽培的方法,对几个杨树新品系的耐盐碱性进行了初步测定。采用方差分析、多重比较、聚类分析的数学手段进行分析,初步确定了不同杨树新品种对盐碱土的适应性及适应范围。结果表明:不同杨树品系的高生长,在同一土壤类型中有显著差异,径生长只是个别品系间的差异显著。在不同土壤类型中同一品系的高生长及径生长差异显著。不同杨树品系在不同土壤类型中的成活率在生长初期变化不大,后期则随着盐碱土含量的增加,苗木生长及保存率都明显降低。当含盐量在0.255%~0.320 7%范围内时,有明显抑制作用;含盐量在0.320 7%以上时,随着时间的推移苗木逐渐死亡。同时根据综合指标确定了10个杨树品系对盐分及pH值的适宜生长范围。     

Avoiding edge effects in agroforestry experiments; the use of neighbour-balanced designs and guard areas

A number of different types of edge effects on experimental plots are defined, and it is shown that they are frequently important in agroforestry experiments. Methods of eliminating edge effects, either at the design or the analysis stage, are described. Computer simulations, based on uniformity data, are used to investigate the efficacy of neighbour-balanced designs, with and without neighbour terms, for reducing the problem of neighbour effects between different treatments. It is concluded that, while neighbour-balanced designs may be useful in certain situations or in combination with other methods, it is preferable to eliminate edge effects by using adequate guard rows. Recommendations are therefore made concerning the correct use of guard areas in agroforestry experimentation.     

农药新剂型——微乳粒剂配制的可行性研究

以三唑磷为模式农药,研究了一种外观为颗粒状、用水稀释后成微乳液的农药新剂型——微乳粒剂配制的可行性。以乳状液的中位径(D50)为因变量,各表面活性剂用量为自变量,采用混料均匀试验设计并结合偏最小二乘回归法筛选表面活性剂品种;用比例法与对分法优化各表面活性剂用量;采用旋转挤压造粒法造粒。将筛选获得的农乳500与农乳602号用于配制15%三唑磷微乳粒剂,其乳状液外观为淡蓝色透明状,分散相颗粒迁移速度为0,且不同水质(水硬度:0~3 420 mg/L,水温:10~50 ℃)下乳液稳定性均合格;乳状液D50为54.2 nm,粒径分布范围为15.7~122 nm,粒径增大速率为0.01%/min;乳状液在相对离心力10 730×g下离心5 min未发生相分离。结果表明:该三唑磷微乳粒剂的乳状液为微乳液,微乳粒剂可以成功配制。