改进型微动力一体化生物膜反应器处理灰水并回用研究

[目的]为灰水的利用提供依据。[方法]利用改进型微动力一体式生物膜反应器处理灰水,监测了进出水的CODCr、LAS、TN和SS以及反应器的温度、pH值和DO。[结果]进水CODCr平均为188 mg/L,出水CODCr平均为32 mg/L,CODCr去除率为80.2%~86.9%。当水力停留时间(HRT)≤3 h时,系统对污染物的去除率随停留时间的延长增长较快。当HRT>3 h时,系统对污染物的去除率随停留时间的延长增长变缓;HRT=3.5 h时,系统对CODCr、LAS的去除率分别为91.7%、81.2%。反应器在常温下按HRT=3.5 h运行时,处理后灰水符合《生活杂用水水质标准》的要求。CODCr、LAS的去除率随温度变化变化不大,TN的去除率下降了40.4%。[结论]改进型微动力一体化生物膜反应器的最佳水力停留时间为3.5 h,系统对CODCr、LAS的去除率分别为91.7%、81.2%。     

采样频率和时间对轴流泵压力脉动特性的影响

为了更准确地分析轴流泵的压力脉动特性,基于结构化网格,在考虑叶顶间隙的情况下,以时均N-S方程为基本控制方程,采用标准k-ε双方程湍流模型和SIMPLEC算法,对轴流泵模型进行了不同的采样频率和采样时间下的全流场非定常数值计算,并分析其对计算结果的影响．结果表明:在进行压力脉动分析时,若取静压作为傅里叶变换的纵坐标,频域图中频率为0时的物理意义即该点平均静压值;采样频率和采样时间对轴流泵压力脉动时域特性和频域特性具有重要影响,指出了因采样频率过小而导致的混叠现象在时域和频域中的表现;并推导出当保证采样时间与叶轮周期和叶片数乘积的比值达到整数倍关系时,基频处不会发生频谱泄漏,并建立了普遍适用轴流泵压力脉动数值计算采样时间的选取公式,进而从公式得出针对不同转速的轴流泵,应选择不同的采样时间．结果为进一步分析轴流泵压力脉动提供了一定参考．     

立式混流泵异常振动测试分析

针对某泵站立式混流泵机组异常振动现象,采用低频振动传感器和电涡流传感器,分别测试开机过程和正常运行时水泵机组下机架、泵盖、外筒体振动以及主轴摆度.基于希尔伯特-黄变换进行试验数据处理,获得了测试信号位移峰峰值,通过提取稳定运行时的振动信号特征向量,对故障类型进行识别;在此基础上,通过分析开机过程信号时频变化情况,寻找诱发机组异常振动的故障原因.现场振动测试分析结果表明:稳定运行时机组振动频率主要集中在转频附近,且主轴轴心轨迹成椭圆形,可诊断其故障类型属于转子不平衡;在开机过程中,主轴的轴心轨迹紊乱,开机瞬间机组的振动值为正常运行时振动值的473倍,据此可判断出在此刻机组内部产生了强大的冲击力,进而引起转子不平衡运转.采用希尔伯特-黄变换法能够准确获取水泵振动信号的时频特征,尤其对分析处理高度非线性的被测信号具有很强的优势,而开展开机过程中的振动测试研究,也为水泵故障诊断分析方法开辟了一条新途径.     

Florfenicol depletion in edible tissue of rainbow trout,Oncorhynchus mykiss (Walbaum), and sea bream,Sparus aurata L.

An increase in fish production has consequently brought an increase in infectious diseases in fish farms. The use of chemotherapic drugs is the most effective instrument against common bacterial agents. The number of registered drugs for use in aquaculture is limited and often veterinary practitioners resort to the off‐label use of chemotherapic agents authorized for different food‐producing animal species. Florfenicol is well known for its outstanding effect against various pathogenic bacteria affecting fish, and therefore, it may be a useful drug for off‐label use in aquaculture. The aim of this study was to evaluate the depletion of florfenicol and its major metabolite, florfenicol amine, from the edible tissue of two fish species, rainbow trout and sea bream, following treatment with medicated feed at a dosage of 10 mg kg^?1 of bw day^?1, for 10 consecutive days. At prefixed time points after the end of administration (0.25, 1, 2, 3, 4, 6, 7, 10, 14 and 21 days after treatment), edible tissues (muscle plus adherent skin) from 15 individuals in each group were collected and analysed by HPLC, to determine concentration of the drug in the tissue. On the basis of the obtained concentrations, withdrawal times of florfenicol in the two species were calculated. The results indicate that a drug withdrawal time of 500 °C‐day, as established by Directive 2004/28/EC, for off‐label drug use is more than satisfactory to guarantee the healthiness of fish products against the risk of drug residues.     

Enhanced detection of infectious salmon anaemia virus using a low‐speed centrifugation technique in three fish cell lines

Infectious salmon anaemia (ISA), caused by ISA virus (ISAV), is a serious disease of farmed Atlantic salmon, Salmo salar L. Recently, molecular‐ and immunofluorescent‐based techniques have become powerful diagnostic tools for ISAV detection, but culture‐based techniques remain the gold standard. A disadvantage of ISAV culture is that the incubation time required before cytopathic effect (CPE) is observed in cell monolayers. To decrease time until CPE is observed, a low‐speed centrifugation technique was applied to existing standard operating procedures for ISAV culture in three fish cell lines. Time until CPE observation was compared in CHSE, SHK and ASK cells, treated or not treated with low‐speed centrifugation after inoculation with ISAV. Low‐speed centrifugation treatment significantly enhanced observable cell infection. Compared to control cells, the length of time until ISAV CPE observation decreased in centrifuged ASK and CHSE cells. Low‐speed centrifugation was also incorporated into a modified clinical shell vial assay. At 48 h post‐inoculation with approximately 20 viral particles, ISAV was detected by an immunofluorescence antibody test in treated ASK and SHK1 cells but not in control cells. Finally, this enhanced viral adsorption assay performed in ASK cells demonstrated higher sensitivity than a real‐time RT‐PCR assay performed on RNA isolated from ISAV‐spiked salmon kidney homogenates.     

利用注射叶片法快速鉴定大豆GmCRY1和GmCRY2基因功能

将大豆隐花色素基因GmCRY1、GmCRY2构建在N端含有绿色荧光蛋白(GFP)的pEGAD载体上,并转化农杆菌EHA105菌株.将含有上述基因的EHA105菌液分别注射到大豆单叶及复叶叶片中,观察长日条件下(16 h光照/8h黑暗)和短日条件下(8h光照/16 h黑暗)注射植株的开花时间.结果叶片注射含GmCRY1基...     

湘东地区三熟制油菜播期及适宜密度研究

为探讨湘东地区三熟制直播油菜不同播期下的适宜栽培密度,2010 ～2011年度,以偏早熟油菜品种丰油730为材料在醴陵市进行了播期与密度田间试验.结果表明:湘东地区三熟制栽培,10月10 ～30日播种,播种越早产量越高,适宜播期为10月25日前.10月10日播种,密度以37.5万～45.0万株/hm2较为适宜;10月15 ～20日播种,适宜的密度范围为45.0万～52.5万株/hm2;10月25日播种,52.5万～60万株/hm2的密度较合适;10月30日播种,密度应达到60万株/hm2.     

密集烘烤关键温度点稳温时间对烤烟理化性状的影响

针对密集烘烤存在的干物质降解不充分和香气物质不足的问题,以K326品种为材料,在湖南省浏阳市开展了密集烘烤关键温度点稳温时间对烤后烟叶物理特性和化学成分影响研究.结果表明,在烟叶变黄期和定色期适当增加稳温时间,可增大烟叶收缩形变,降低叶质重,降低单叶重,增加烟叶疏松性,降低烟叶淀粉含量,增加总糖和还原糖含量.但过度延长稳温时间,将导致烟叶内含物消耗过多,降低烟叶品质.对中部和上部烟叶,在变黄期的38℃稳温24h和42℃稳温16 h,在定色期的47℃稳温18h和54℃稳温16 h为适宜;对下部烟叶,在变黄期的38℃稳温15 h和42℃稳温16 h,在定色期的45℃稳温12 h和54℃稳温16 h为适宜.     

收获期对春植花生种子繁殖的影响

研究结果表明,春植花生种子中蛋白质、脂肪和亚油酸含量与产量一样均随着荚果发育而呈增加趋势;油酸含量却呈下降趋势。播后90d以前收获的种子,出苗率低,植株长势弱,产量低,繁殖系数小。播后95d种子的出苗率及繁殖系数等与充分成熟的种子差异不明显,为最早适收期。     

北方冬季室内饲养灰飞虱的方法

以水稻苗和小麦苗作为灰飞虱寄主植物,探讨了北方冬季室内饲养灰飞虱的方法。结果表明,该技术简便易行,能够准确把握虫龄,可大量扩繁也可单头饲养,具有成本低,易操作,灵活性好等特点;试验测定了在28℃条件下,若虫存活率可达到95.36%,单雌产卵量达到177头。