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941.
地理标志农产品是地方优良物质文化财富,是推进品牌强农、质量兴农的重要举措。建设地理标志农产品追溯体系,有利于保护地方特色,积极推动特色产业发展、振兴乡村经济、弘扬农耕文化,同时也能够保证农产品食用安全,提升政府监管效能,降低食品安全风险。对洛阳市地理标志农产品追溯体系建设和应用情况及存在的问题进行了分析,并对未来加强地理标志农产品追溯体系建设和发展的方向进行了展望。 相似文献
942.
A coking plant extended many times, and its capacity of the cooling water system is not match with it, the consumption of new water is much more than that used by others in the same industry. The water system renovation is addressed for an extended coking plant. The installation of two 600 m3/h cooling towers and restoration the existing two cooling towers are to promote the cooling capacity so that the amount of discharge and feed could be reduced. At the same time, the pipe net for waste water reutilisation is installed, by which part of the waste water is reused as supplement water for quenching hot coke and the other was piped to ironworks for reuse. With the field test, the water consumption per ton of coke production is cut down from 9.03 m3 to 3.21 m3. And the annual water saving is more than 6×106 m3. Furthermore, the electric consumption is reduced by 2×106 kWh and about 3×106 yuan of annual running cost is saved. 相似文献
943.
The differential equation which governs the behavior of the gear transmission system of 1.5 MW wind turbine is established. The external excitation caused by wind speed fluctuation is discussed and the internal excitation due to time varying mesh stiffness and comprehensive error is also analyzed. The calculating formulations of the harmonic balance method of nonlinear dynamic equations are presented. Then, the multi objective dynamic optimization model is developed to minimize the value of vibration acceleration and the overall volume. The optimization of a practical example using mixed discrete combined programming is performed. The result shows that the proposed method of modeling and optimization design can effectively reduce the wind turbines gearbox vibration levels and weight. 相似文献
944.
Aiming at the hydraulic system of CVT (Continuously Variable Transmission), the transfer function of hydraulic system of CVT and the dynamic simulation model of this system based on AMESIM are built, and the characteristics of speed ratio response is simulated and calculated. The influences of spring constant, damping coefficient and mass of moving part on rising time, setting time and overshoot are analyzed. The result shows that the dynamic simulation model of this system is reasonable and will provide a basis and method for the optimization of CVT hydraulic system’s dynamic characteristics in the future. 相似文献
945.
Field experiments were conducted over two growing seasons to investigate the effects of variations in water regime and planting pattern on the growth of rice plant roots and shoots and on yield. Four water regimes were evaluated with split plot design: intermittent flooding during the vegetative stage only (IF‐V); intermittent flooding extending into the reproductive stage (IF‐R); not flooded (NF); and continuously flooded (CF), interacting with three different planting patterns: single seedling per hill with wider 30 × 30 cm spacing (P1); single seedling per hill with closer 20 × 20 cm spacing (P2); and three to four seedlings per hill with 20 × 20 cm spacing (P3). The treatment combination CF/P3 corresponds most closely with current conventional practice. The other combinations were evaluated to contribute to a better understanding of the effects of the two parameters studied, respectively and together. IF‐V/P1 was considered as an approximation of System of Rice Intensification (SRI) practice. This study found that the combination of singly transplanted seedlings, both P1 and P2, with the IF‐V water regime improved root length density, root physiological activity, and chlorophyll content of the upper and lower leaves, leading to higher grain yield compared with the other treatment combinations. With continuous flooding (CF), P2 gave 23 % more yield compared with the P3 planting pattern. Combining IF‐V and P2 produced 32 % more grain yield compared with the CF/P3 treatment. These results showed a synergistic effect on grain yield from reduced intra‐hill competition and IF‐V water management. In these trials, there was no significant yield difference between the IF‐V/P1 and CF/P3 treatments. Wider spacing improved the performance of individual hills when grown under IF‐V water regimes, but tiller number per unit area remained a dominant determinant of yield. The yield reduction observed for CF/P1 compared with CF/P3 indicated that in more hypoxic CF soils, denser plant populations can produce more than sparser ones, whereas the latter benefit from more aerobic soil conditions. Intermittent irrigation during the vegetative growth stage and transplanting single seedlings/hill are major elements of SRI methodology. These findings contribute to an understanding of why SRI methods can produce the higher yields reported. A consideration of the effects of interaction between planting pattern and water regime shows the need to establish empirically the optimum values for these treatments according to varietal, soil and climatic characteristics for the greatest yield response. 相似文献
946.
947.
正交设计优化扁蓿豆ISSR反应体系的研究 总被引:6,自引:0,他引:6
以扁蓿豆(Medicago ruthenica)为试材,采用改良的CTAB法提取DNA,利用正交设计L16(45)探讨10×PCRBuffer(含Mg2+)、dNTPs、引物、TaqDNA聚合酶及模板DNA用量对扁蓿豆ISSR-PCR反应的影响,正交试验的结果采用直观分析和方差分析相结合。建立了扁蓿豆的ISSR-PCR优化反应体系,在25μL反应体系中,TaqDNA聚合酶1.5U,10×PCR Buffer(含Mg2+)2.0 mmol/L,模板DNA0.5 ng/μL,dNTPs 0.6 mmol/L,引物0.9μmol/L。同时探讨引物HZD09211的最适退火温度为52.3℃。2个不同引物对20份扁蓿豆材料DNA进行ISSR-PCR扩增,结果显示该体系具有较高的稳定性。 相似文献
948.
米曲霉和黑曲霉双菌种制曲对豆酱酶系影响的研究 总被引:1,自引:0,他引:1
以黄豆和面粉为主要原料,以淀粉酶、蛋白酶、β-葡萄糖苷酶和纤维素酶的活性为指标,采用单因素试验方法,研究米曲霉和黑曲霉(质量比为1:1)对豆酱制曲酶系的影响,优化制曲工艺参数。试验结果表明,采用添加熟面粉的方式,制曲时间为36h,制曲温度为29~32℃,接种量0.04%,双菌种曲中酶的活性高于单一米曲霉曲。 相似文献
949.
950.