通州区：金鱼、锦鲤大赛暨鉴赏会举行

近日，北京市第二届中国金鱼、锦鲤大赛暨鉴赏会在北京市通州区张家湾镇北京鑫淼水产总公司隆重举行。     

观赏鱼--异军突起的世界性水产养殖兴盛产业

鱼类的经济价值有食用和观赏两个方面。供作观赏的鱼类叫做：观赏鱼。观赏鱼一般体形比较奇特，体色较为艳丽多彩，并且容易在微小的水体里如水族箱饲养。据资料，世界的鱼类有5万种左右，其中有观赏价值的约为2～2千种，利用普遍的则在500种左右。观赏鱼的绝大部分是淡水鱼类，海水观赏鱼只占观赏鱼总数的10％～20％，加上饲养海水观赏鱼难度较大，所以，市场上常见的观赏鱼，几乎多是淡水品种。     

近代中国最早的防疫工作

1910年12月,东北省发生了大规模的鼠疫,病因不明,死亡率极高,并迅速蔓延于关内直隶、山东及北京、天津等城市。迫于各方压力,清政府起用了毕业于剑桥的医学博士伍连德为防疫处总医官,统领防疫工作。他依据世界上最新的防疫理论,严格的科学方法,积极的措施,在不到4个月的时间     

番茄晚疫病发生规律及防治技术

1发生规律 番茄晚疫病在我镇一年有两个流行高峰。平坝地区5月下旬至7月上旬为第一流行期，9月至11月为第2流行期，以第二流行期发生最重，为害最大，番茄晚疫病流行高峰一般6月7至19日为第1流行高峰期，9月18至28日为第二流行高峰期。     

天牛的综合防控对策

天牛在我国有十几种,危害植物种类繁多,防治困难。本文是对天牛的综合防控实施相应的对策,供各位参考。     

碳点增强的Ru纳米颗粒复合材料用于碱性条件下高效电解水析氢

In the 21st century, hydrogen energy is a novel energy source. Its use is expected to mitigate the problems of environmental pollution and global warming caused by the excessive use of conventional fossil fuels. The hydrogen evolution reaction (HER) for water splitting has attracted considerable attention because of its environmental friendliness. To improve electrocatalyst performance and reduce operation cost, carbon-based metal hybrid materials exhibiting high efficiency and catalytic activity have been developed. Among them, carbon dots (CDs) have garnered significant research attention and have been widely applied in biosensing, bioimaging, and energy conversion/storage because of their facile synthesis, biocompatibility, tunable photoluminescence, excellent stability, and good electronic properties. CDs are widely used as carriers in the construction of electrocatalysts prepared from carbon-based metal hybrid materials. At present, it is believed that CDs exhibit excellent confinement effects, which can effectively inhibit the growth and agglomeration of metal nanoparticles, thereby preparing well-distributed carbon-based metal hybrid materials with a uniform and controllable size. However, the formation process of the small-molecule raw materials of CDs has not been elucidated. In this study, CDs and small-molecule raw materials from synthetic CDs were used as precursors to prepare nitrogen-doped CD-supported ruthenium nanoparticle (Ru@CDs) and small-molecule-supported ruthenium nanoparticle (Ru@Molecule) hybrid materials, respectively. The interaction between the small molecules and Ru in the process of CD formation and the effect on HER performance were explored. Moreover, we prepared different carriers such as metal organic frameworks(MOF), carbon nanotubes (CNTs), and graphene (GO)-supported ruthenium nanoparticle hybrid materials. Among them, Ru@CDs exhibited controllable size and excellent dispersibility and exhibited outstanding HER activity and good stability. Ru@CDs were found to require a low overpotential of 22 mV to reach a current density of 10 mA·cm⁻². Moreover, we observed the presence of an intermediate state between the molecules and CDs and demonstrated that the intermediate state exhibits no confinement effect. Furthermore, we found that with increasing calcination temperature, the intermediate state gradually changes to CDs. The unique spatial confinement between CDs and metal ions is key to the formation of monodisperse Ru nanoparticles. Our results confirmed that Ru@CDs serve as excellent HER catalyst supports. This work not only reveals the effect of the unique spatial confinement of CDs on the supported metals and their promoting effect on electrocatalytic activity but also provides guides the future development of CD-based metal hybrid electrocatalysts.     

发展中国家主要作物的病毒和类病毒病

植物疫病是影响世界粮食生产的重要因素之一，每年由病毒和类病毒造成的粮食减产约占粮食减产总量的20％。此外，病毒和类病毒疫病还会带来一些意想不到的经济和生态上的影响。所以．培育抗病品种，提供无毒材料是进行疫病防治的基础。深入了解每种病毒的变种或毒株的有关知识及分布是开展抗病育种的前提。     

绿洲生态农业建设是新疆农业发展的必由之路

新疆的农业生产在近几年取得了巨大的成就，但由于水资源利用失调，土地沙漠化严重，化学制品污染及农业结构不合理等问题，导致生态环境恶化，农业面临着严峻的挑战。因此，建设绿洲生态农业成为新疆农业发展的必然选择。新疆绿洲生态农业建设应当以现代技术为核心，以人、水、土为支点，以外部生态环境治理相协调，构建新疆生态农业建设体系。