Nitrogen fertiliser source effects on the growth and mineral nutrition of pepper (Capsicum annuum L.) and wheat (Triticum aestivum L.)

BACKGROUND: The presence of stable mixed nitrogen forms (such as nitrate/ammonium/urea or nitrate/urea) in the soil solution is due to the use of nitrification and/or urease inhibitors in urea‐based fertilisers. However, there is no specific information in the literature comparing the efficiency of these urea mixed nitrogen forms as a nitrogen source for plants with that of nitrate and ammonium/nitrate. The aim of this study was to compare the effects on plant growth and mineral nutrition of different nitrogen forms, including mixed nitrogen forms containing urea. RESULTS: The results indicated that for both wheat (Triticum aestivum L.) and pepper (Capsicum annuum L.) the growth of plants fed mixed nitrogen forms containing urea was generally similar to that of plants receiving nitrate and nitrate/ammonium. Only in the case of pepper did ammonium/urea nutrition cause a significant decrease in plant growth. The presence of nitrate corrected the negative effects of mixed nitrogen forms containing ammonium and/or urea on the growth of pepper plants. CONCLUSION: Mixed nitrogen forms containing urea did not cause any negative effect on plant growth or mineral nutrition. In fact, plants fed mixed nitrogen forms containing urea had higher shoot concentrations of potassium, phosphorus, iron and boron than plants receiving nitrate. Copyright © 2007 Society of Chemical Industry     

Continuous production of sialyllactose from colominic acid using a membrane reactor

Continuous production of sialyllactose, as a typical sialylsaccharide, was examined using a membrane reactor. The synthesis of sialyllactose through the transfer reaction catalyzed by neuraminidase, has been reported to be a suitable process for industrial production, but it still has drawbacks such as a low yield, high enzyme cost, and hydrolysis by the enzyme of sialyllactose formed. We attempted to solve these problems by utilizing an appropriate membrane reactor system. We first investigated the effects of various reaction conditions on sialyllactose productivity, and found that the productivity was independent of the enzyme concentration and reaction temperature but dependent on the substrate and buffer concentrations and the hydraulic retention time (HRT). We then selected a suitable membrane that allowed sialyllactose to permeate but rejected the substrate and enzyme. Finally, we constructed a membrane reactor system with a cut-off molecular weight of 3000 and applied it to continuous sialyllactose production from colominic acid at an HRT of 80 min. Using substrate concentration of 25 g/l the system performed with a high level of productivity and gave a good yield, while maintaining high transfer ratio of 4-5% over a 160-h test period.     

用户侧互动模式下的微电网优化协调调度策略研究

随着可再生能源的不断渗透,微电网的管理呈现出复杂性与多样性,制定高效的调度策略不仅能够减轻大电网的负担,更能实现彼此互利共赢。文章针对同时具有风光柴储的典型微电网,研究在并入外部电网的情况下,最大化地发挥用户侧与微电网的互动潜力,协调各微电源之间出力得到优化调度策略。最后,依据所提出的评价指标对每一种优化调度策略进行评估。通过仿真与对评价指标的计算,验证了所提出调度策略的有效性与合理性。     

Effect of weft density and percentage of stainless steel fiber content of weft yarn on electrical properties of woven fabric strain sensors

Textile-based strain sensors have been used in smart textiles frequently. In this study, effect of percentage of stainless steel fiber of spun yarn (i.e. 28 and 40%) and weft density (i.e. 14, 18, and 22 per cm) of conductive yarn on performance and sensitivity of woven fabrics strain sensor under tensile cyclic loading in 3 mm elongation and also behavior of woven fabric strain sensors under simple tensile loading, was studied. Our finding showed the interaction between weft density and percentage of conductive fiber of spun yarns on performance and sensitivity of strain sensors under cyclic loading. Samples prepared by conductive yarns with 40% stainless steel fiber showed no clear cyclic variation in 18 and 22 weft per cm. This trend for samples woven with conductive yarn with 28% stainless steel fiber was only observed in 22 weft per cm. All samples showed the same trend of resistance variation during simple tensile loading, although the level of resistance variation was different. The slope of resistance variation during tensile cyclic loading confirmed plastic deformation of samples. Finally, by comparing the sensitivity of strain sensors during cyclic loading no obvious advantage was obtained for samples woven with conductive yarn with 40% stainless steel fiber compared with samples woven with conductive yarn with 28% stainless steel fiber.     

网络信息对声学专利申请新颖性/创造性的影响

从声学领域中两个具体的案例出发,探讨了声学领域专利申请的检索思路和网络信息的特点和效力,从而对网络信息对声学领域专利申请新颖性/创造性的影响进行了分析.     

Improvement of the Classification Performance of a Rectangular Jet Virtual Impactor

The effect of flow characteristics on the performance of a virtual impactor with a rectangular jet has been studied experimentally. Flow visualization revealed a three-dimensional flow structure and flow instability on the classification performance, classification experiments were carried out using the virtual impactor with an improved collection nozzle which was designed to avoid the adverse pressure gradient. The newly designed collection nozzle improved the classification performance in the high inertia region, which is larger than a cut point of the virtual impactor. However, the separation efficiency is still lower than that predicted by the theory based on the two-dimensional flow. Since the flow visualization revealed that the flow in the classification zone was partially disturbed by the new collection nozzle, the entrance part of the impactor was newly designed to introduce 2 additional clean airflows. These clean airflows prevented flow disturbance and attained the theoretical classification performance in the high inertia region.     

Preparation of SrBi2(Ta,Nb)2O9 thin films by rf sputtering for ferroelectric memory production

Abstract

Ferroelectric SrBi₂(Ta, Nb)₂O₉ (SBTN) thin films were prepared by rf magnetron sputtering utilizing a multi-chamber type production tool (ULVAC CERAUS ZX1000). Accurate and dynamic compositional control results in excellent ferroelectric performances such as large 2Pr up to 15μC/cm², fatigue free at least 10⁹ cycles as well as good uniformity and process repeatability. These results indicate that the SBTN sputtering process is promising for ferroelectric memory production.     

Cyclopolymerization of Amino Acid-Based Diynes and Properties of the Obtained Polymers. Chiral Recognition and Metal Ion Extraction

Summary Cyclopolymerization of amino acid-derived novel dipropargyl ester and dipropargylamide was carried out using a rhodium catalyst. Polymers with cyclized structures were obtained under certain conditions. The dipropargylamide polymer exhibited a large specific rotation and an intense Cotton effect around 300 nm based on the chiral higher order structure. It adsorbed N-benzyloxycarbonyl-L-alanine more than the D-isomer, and extracted Li⁺, Na⁺, K⁺, and Cs⁺ from water phase into CH₂Cl₂ phase.     

Direct observation of channel-tee mixing of high-temperature and high-pressure water

Channel-tee mixing of flowing high-temperature and high-pressure water streams was observed by using a newly designed high-pressure optical cell and results were compared with mixing at room temperature. The characteristic feature of the cell is a three-piece window with the center window containing a mixing channel. The mixing between aqueous streams at high-temperatures and high-pressures greatly depended on the mixing direction and it was found that gravity played an important role, even for mixing between streams of small diameters (2 mm).