寒区桥梁用自密实混凝土试验研究

通过对自密实混凝土进行快冻法和3%NaCI溶液的冻融循环试验,测定不同冻融循环次数后的质量损失率和相对动弹模量及其变化特点以及冻融损伤对氯离子扩散能力的影响。结果表明：自密实混凝土随着冻融次数的增加,其表观质量、力学性能均呈现不同下降趋势。可为寒区桥梁工程设计、养护及寿命预测提供依据。     

气化炉在自控组合式密集烤房中的应用研究

为解决烤房建设与改造中的重复投资问题,同时最大限度地减少土地资源的浪费和能源的消耗,研究自控组合式密集烤房及气化炉在烟叶烘烤中的应用效果。结果表明:应用气化炉的自控组合式密集烤房相对于普通密集烤房平均可减少烤烟用工4.8个/房烟,降低鲜干比0.54,节约烘烤成本0.41元/kg,提高上等烟比例5.4个百分点,均价提高0.66元/kg,同时可增加烟叶的还原糖含量,降低烟碱含量。     

浅谈引黄灌区发展井渠结合灌溉工程的必要性

在引黄灌区,采取井渠结合这种方式是提高灌溉水资源利用率和用水保证率的良好途径。     

奶牛3型口蹄疫间相互影响及联合免疫程序

由于目前尚无可靠的A型-O型-AsiaⅠ型3联疫苗,所以3型口蹄疫的免疫则采用A型单苗和O型-Asia-Ⅰ型2联苗联合进行,但各疫苗的免疫时间及联合免疫程序均未进行过深入地研究,联合免疫效果有待实验的验证。通过对奶牛3型口蹄疫抗体水平的跟踪检测,最终结果表明:奶牛3型口蹄疫间相互影响不显著,在犊牛90日龄可以同时进行首免,但要左右两侧分2针注射;首免后28d以同样的方法进行2免;抗体持续4个月后进行3免;以后每隔4个月加强免疫1次,方法都与首免相同;或根据抗体监测水平及时进行补免,都会起到一个良好的保护作用。     

Combined effect of temperature,salinity and density on the growth and feed utilization of Nile tilapia juveniles (Oreochromis niloticus)

Based on Box–Behnken experimental design and response surface method, the joint effect of temperature (16–36°C), salinity (0–22 ppt) and rearing density (200–1000 fish.m^?3) on the specific growth rate (SGR) and feed conversion rate (FCR) of Nile tilapia juveniles were studied under laboratory conditions. The entire experiment lasted for 1 month (30 days). Results showed that the linear and quadratic effects of temperature, salinity on both growth and feed utilization were highly statistically significant (P < 0.01). The linear and quadratic effect of rearing density on the growth was highly significant (P < 0.01); the linear effect of rearing density on feed utilization was significant (P < 0.05), but the quadratic effect nonsignificant (P > 0.05). Interactions between temperature and salinity, and between salinity and rearing density on the growth statistically differed from zero (P < 0.05). Interactions between temperature and salinity, between temperature and density on feed utilization was significant (P < 0.05). Model equations of the growth and feed utilization on temperature, salinity and density were established, with the coefficient of determination being 98.34% for growth and 98.11% for feed utilization, and could be applied to projection. The optimal temperature/salinity/density combination was obtained utilizing statistical optimization approach: 29°C/6 ppt/500 fish.m^?3, at which the maximal specific growth and feed utilization reached 4.228%.d^?1 and 0.520 respectively, with the desirability being 0.989.     

A New Method for Measuring Bonding Shear Properties of Adhesives on Steel Substrates

Single-lap-joint adhesively bonded metal specimen which is the national standard experimental method in use has an extremely non-uniform distribution of shear stresses along the joint, and tensile stress concentration of high values is produced on the steel substrate interfaces. Therefore the test result, which is not the real bonding shear strength between adhesive and steel substrates, can only be used as a test index for qualities of adhesives not the strength criterion for load is capacity evaluation. The combined bonding disc specimen is adopted for measuring bonding shear properties of adhesive on steel substrates, has a very uniform distribution of shear stresses in adhesive and along the bonding surfaces of steel substrates, of which the uniform coefficient is greater than 0.97. Furthermore, when adhesive joint is treated as an arc and steel substrates are chamfered at both ends of the joint, tensile stresses on the bonding surfaces can be reduced to less than 20 MPa which can hardly cause tensile failure. Thus, the results of combined bonding disc specimens can actually represent the real bonding shear strength or bonding shear-compression strength between adhesive and steel substrates, which can be used as strength criterion for load capacity evaluation of bonding members.     

供氮水平和有机无机配施对夏玉米氮利用效率的影响

通过大田试验研究了不同氮素水平下有机无机肥料配施对夏玉米氮利用效率的影响。结果表明,氮素肥料的各去向受施氮量影响较大,施氮量越大,表观残留量、淋溶损失量、气态损失量均增加。表观利用率在施氮低于200 kg/hm2时,表现为增加,高于200 kg/hm2时,则表现为减少。配施有机肥比例越大,表观利用率、表观淋溶损失率越小,表观残留率则越大。气态损失率在有机无机配施条件下最小。淋溶损失是氮素肥料的主要损失途径。综合考虑,氮肥表观利用量、表观残留量和淋溶损失量,以纯氮施入量200 kg/hm2,75%的N由有机肥提供、25%的N由尿素提供的处理为较理想的氮素施用水平和配比组合。     

板栗仁酶促褐变产物的组分确定

 [目的]研究板栗酶促褐变产物的组分。[方法]利用提取纯化后的板栗酶促褐变产物组分作为试材,采用HPLC法对其进行定性和定量分析;采用NMR法进一步确定板栗酶促褐变产物组分。[结果] HPLC法初步断定5%碳酸氢钠萃取组分为大黄酸;5%碳酸钠萃取组分为大黄素;核磁共振实验测定的2个组分的1HNMR和13CNMR图谱分析结果确定了板栗仁酶促褐变产物为大黄酸和大黄素。[结论]本研究可以为板栗酶促褐变机理研究以及产物安全性提供重要的依据。     

化学-生物联合技术对重金属-有机物复合污染土壤的修复研究

重金属-有机物复合污染是当今土壤污染中最普遍的一种,利用传统的化学修复法或现阶段比较盛行的各种生物修复法,如超积累植物富集修复、微生物降解修复等都难以对重金属-有机物复合污染土壤进行彻底治理修复。主要就利用化学-生物联合技术修复重金属-有机物复合污染土壤的反应机理以及修复中存在的问题进行研究探讨,并对该技术今后的发展方向进行展望。     

Atmospheric Environmental Impact Simulation of Gas Fired Boilers as Peak Load Heat Sources

Heating with gas can reduce air pollutant emission and therefore becomes a new sort of peak load heat source. To study the atmospheric environmental impact, we adopted a newly built combined heating system and simulated its pollutant dispersion for centralized and distributed peak heating. The simulations were based on the improved regulatory environmental impact assessment (EIA) guidelines for atmospheric environment. The model developed an algorithm for infill wind direction simulation and exported pollutant contours for comparisons. Simulation results show that the system's atmospheric environmental impact is related not only to the pollution emission quantity per quantificational heating, but also to the distribution of heat resource in the gas fired boilers. The centralized peak heating has comparatively small environmental impact; for distributed peak heating, the more concentration of gas fired boilers distribution is applied, the more serious environmental impact will be. In addition, the optimum setting proportion of gas fired boilers should be between 0.2 and 0.6 from the perspective of environmental impact.