摘要：This study has examined the structure and function of the biliverdin reductase A (BLVRA) gene and its correlation with the green eggshell character in Jinyun ducks. The previously unknown sequences of 3' and 5' ends of duck BLVRA mRNA were cloned, using RT-PCR and 5' RACE methods with four pairs of primers designed from the known coding sequence (CDS) of the duck BLVRA gene. Gene expression levels of BLVRA in the shell gland were quantified by real-time PCR, and eggshell colors were determined objectively by the reflection coefficient. The cDNA sequence of BLVRA was comprised of 1071 nucleotides, encoding a protein of 303 amino acids with an isoelectric point of 7.15 and molecular weight of 34.3 kda. The 5' and 3' ends of the duck BLVRA gene sequence published in the GenBank were extended by 238 and 199 bp, respectively. The deduced amino acid sequence of duck BLVRA had 95.3% identity with Gallus gallus, 95.0% with Taeniopygia guttata, 70.0% with Xenopus tropicalis,61.1% with Bos taurus, 60.5% with Homo sapiens and 59.5% with Mus musculus, which indicated that the BLVRA gene was evolutionarily conserved. The relative gene expression level of BLVRA in shell glands of Jinyun ducks with white eggshells was 3 times higher than that in ducks with dark green eggshells (P<0.01). There was a significant positive correlation between reflection coefficient of eggshells and the relative expression of the BLVRA gene (r=0.719, P<0.05). Together, these findings suggest that the BLVRA gene could be a candidate gene for the molecule breeding of ducks with green eggshells.

摘要：介绍了数控系统硬件、软件的基本结构,重点介绍了进口数控系统汉化设计的一般方法与实现过程,并给出了基于日本某专用系统的汉化设计、研制实例。

摘要：带圆型球头的螺杆、球碗是锻压机床中的重要部件,其质量对机床精度、寿命有重大影响。传统的加工工艺和手段,生产率低、精度差。参照国外同类产品,并根据客户要求及产品特点,引进东芝TOSNUC70-L数控系统,结合国产CA6140车床,完成了该专用车床的设计、生产。用户使用证明,该设计结构简单、操作方便。定位精度:±0.009/200,重复定位精度:±0.004/200;球面粗糙度:Ra0.8。

摘要：A broadband reflective polarization converter is proposed. The unit cell of polarization converter is composed of a single-split resonant ring, a double-split resonant ring, a dielectric substrate and a metallic ground. The simulated results show that the polarization converter can convert x-polarized waves into y-polarized waves and obtain a broadband polarization conversion from 0.501 0 THz to 1.390 0 THz with the polarization conversion ratio(PCR) beyond 80% at normal incidence. Moreover, the surface current distributions are investigated to explain the polarization conversion mechanism. Finally, a good agreement is achieved between simulated and measured results. The polarization converter can be applied in terahertz imaging, communication and stealthy technology.

摘要：介绍了运动模块与数控系统间通信、数据处理、轴位置显示、编程控制等;合理地将此运动模块融入数控系统的控制范畴。使用证明,该设计结构简单、功能强、操作方便。

摘要：建立了巷道式立体车库设计方案参数优化的数学模型,并对其进行了仿真求解。仿真结果为该类型车库选择合理的设计方案提供了量化分析的科学依据。

摘要：本试验旨在研究饲粮不同胆碱水平对绍兴鸭脂质代谢的影响,并探究产蛋鸭最佳的日粮胆碱水平。采用单因子随机分组试验设计,在玉米-豆粕型基础饲粮中分别添加5个胆碱水平(0、250、500、750、1 000mg·kg-1),探讨饲粮中添加不同水平胆碱对绍兴鸭脂质代谢的影响。试验选用刚进入产蛋期的绍兴鸭540只,分为5组,每组6个重复,每重复18只,饲养20周。结果表明:1)与对照组相比,饲粮添加胆碱显著降低了试验鸭肝和胸肌中粗脂肪和胆固醇的含量(P0.05)。2)随着饲粮胆碱水平的提高蛋中胆固醇的含量显著降低(P<0.05),粗脂肪含量显著升高(P<0.05)。3)饲粮添加胆碱显著降低了试验鸭肝和胸肌中饱和脂肪酸(SFA)的比例(P<0.01),显著升高了试验鸭肝和胸肌中单不饱和脂肪酸(MUFA)和多不饱和脂肪酸(PUFA)的比例(P<0.01)。4)饲粮不同胆碱水平对绍兴鸭血浆中胆碱(Ch)含量、脂肪酶活力(LPS)、极低密度脂蛋白(VLDL)、低密度脂蛋白(LDL-C)、高密度脂蛋白(HDL-C)、甘油三酯(TG)、血清磷脂(PL)、游离脂肪酸(NEFA)、总胆固醇含量(T-CHO)、碱性磷酸酶活性(AKP)没有显著影响。由此可知,基础饲粮中添加一定量的胆碱可降低蛋鸭肝和胸肌中胆固醇和粗脂肪的含量,降低蛋中胆固醇的含量,影响肝和胸肌中不同脂肪酸的比例。

摘要：本文分析了我国自20世纪末以来由于经济和社会变化产生的水问题,即包括城市化进程不断加快所导致的城市用水量的不断增加,以及城乡之间水事关系的日益密切;然后从制度的角度分析了水管理模式的改革,即要求改变过去的层级分解-信息包裹模式,建立一定的协调机制或合并有关机构;最后指出在实施城乡水务一体化管理以后,仍然需要正确协调和处理水的资源管理、服务管制和环境管理之间的关系。

摘要：价格是影响用水的最主要因素之一。本文应用入户调查的数据,应用计量经济学方法分析了深圳市城镇居民生活用水的价格弹性和收入弹性;计算了假设的水价调整方案对深圳市城镇居民生活需水的影响,并提出了对深圳市水价调整的建议。分析结果表明,深圳特区内、外在用水行为和价格对用水的影响方面存在明显的差别,目前深圳的阶梯水价设置不合理;价格可以作为调整深圳水资源供需关系的有效手段;为了有效控制用水的快速增加,应同时调整价格水平和阶梯。

摘要：本文分析了以需定供和以供定需的水资源配置模式的特点,并以海拉尔流域为例,阐述了以供定需的水资源配置模式在流域的具体应用。相对于以需定供的水资源配置模式,以供定需的水资源配置模式拥有降低预测的不确定性、可供水量的确定性、经济社会和水资源协调发展和人水和谐性等特点。