MacCormack算法在长输管道瞬变流动仿真中的应用

为了提高长输管道仿真精度和速率,基于MacCormack格式基本原理和流动方程建立了长输液体管道水力瞬变流动仿真模型。以某管道为例,分别采用该仿真算法和特征线法模拟了阀门关闭和流量增加引起的瞬变流动,并探讨了MacCormack格式中不同边界条件处理方法及Courant常数值对模拟结果的影响。结果表明:MacCormack格式可用于精确仿真长输管道瞬变流动过程,采用特征线法求解预估层边界参数后,其振荡幅度、收敛速度均优于特征线仿真方法;同时,采用特征线法处理MacCormack格式边界条件较线性外插法更易收敛。研究成果可为长输管道瞬变流动仿真提供参考。(图8,表2,参22)     

左右岸省界缓冲区水质达标评价方法研究

左右岸省界缓冲区作为协调省际间用水关系的重要水域,其水质达标评价及污染责任划分是流域限制纳污红线制度实施的重要内容。从左右岸省界缓冲区的相关概念出发,根据省份的位置关系将其分为缓冲区完全在两省省界上、缓冲区部分在两省省界上以及缓冲区在多省交界上三种情形,并结合左右岸省界缓冲区特点确定调整浓度核算法、代表断面判断法、限制排污总量-污染物入河量评估法等水质达标评价方法,以判断左右岸省份缓冲区的水质达标情况,从而划分缓冲区左右岸省份的污染责任。实例验证模拟显示,确定的方法切实可行,研究方法可为流域污染责任划分提供技术支撑,从而促进限制纳污制度的顺利实施。     

湿地红线的确定与管理

湿地红线是国家湿地保护法律法规的另一种体现形式，是湿地管理的手段和工具，也是进行湿地评价的尺度和标准。湿地红线的制定已到了关键时期，条件已经成熟，利用目前最新的湿地调查成果，从生态系统安全、社会文化和经济三个方面进行理论指导，科学地确定湿地的数值与空间红线；同时，为了让生态红线真正发挥作用，还需要制定相配套的法律法规，建立相应的考核机制、出台相关经济政策等作为保障。     

Development of Nucleic Acid Lateral Flow Immunoassay Detection Method for Foot-and-mouth Disease Virus

In this article, through the combination of nucleic acid probes and immune chromatography, a simple, sensitive and specific detection system——nucleic acid lateral flow immunoassay (NALFIA) for amplifing foot-and-mouth disease virus (FMDV) 3D RT-PCR products was established.An ultrasensitive nucleic acid biosensor (NAB) based on streptavidin-labeled gold nanoparticles dual labels and lateral flow strip biosensor (LFSB) were used in this system.The biotinylated goat anti-rabbit IgG was marked to the NC membrane as the alleged strip and the anti-digoxin antibody was labeled to the NC membrane to capture the digoxin probe.After assemblying gold-labeled strip and detecting RT-PCR products, the detection limit of NALFIA was 0.3×10^-3 to 3×10^-3 μg/μL.The NALFIA was compared with agar gel electrophoresis analysis, the results showed that the sensitivity of NALFIA was higher than agar gel electrophoresis.There was an excellent agreement between the two methods.NALFIA was a method with high sensitive, low cost and short time.In conclusion, this method provided a good alternative to detect FMDV.     

The Standardization of an Apparatus for the Mixing of Soil Samples for Nematode Extractions

Quantitative determination of nematode populations in soils frequently necessitates the mixing of representative soil samples to form a homogeneous, compound sample from which the nematodes are extracted. A mixing apparatus was developed and standardized with the aid of a spectrophotometric technique by which the dispersion of a dye through the soil during mixing could be determined. It was found that the mixer is most suitable for use on sandy loam soils. Optimal mixing is obtained at a speed of 15 rpm for 2 minutes. Under these conditions mechanical damage to nematodes during mixing is minimal.     

高效节水灌溉管道流量计算原则初探

对于管网优化及投资分析来说,最不利情况下的水力条件不是普遍条件,不能够完全代表管网应当有的优化假定条件。通过管道控制灌溉面积来确定管道的流量,按照满足在一天内,管道控制的所有灌水器都灌溉一次的原则确定,并给出公式。让管道的流量这一重要参数,在高效节水灌溉工程优化和设计计算中变得简单并容易计算。     

水头可调薄壁堰式渠道流量智能测控系统优化试验研究

采用巴赞堰流公式计算流量的水头可调薄壁堰式渠道流量智能测控系统通过渠道流量量测与控制试验,验证了其精准的测流功能和智能控制技术的可行性。为进一步提高该测控系统运行的效率和稳定性,减少运行能耗,对矩形薄壁堰堰流公式进行水力试验研究,通过分析堰上水头和流量关系,拟合出矩形薄壁堰流量计算公式。通过向该拟合公式引入修正系数λ=0.848,将测控系统测得的堰上水头数据值代入该拟合公式求得的流量值与电磁流量计测得流量值的差值的平均值为-0.004L/s,标准差为0.119,线性相关系数R2=0.989 1。该拟合公式相对于巴赞堰流公式形式简单、参数较少、运算简便,同时也满足节水灌溉对精准测流的要求,更适用于水头可调薄壁堰式渠道流量智能测控系统,对于在灌区推广和使用该测控系统具有重要的意义。     

The Fluorescent Characterization and Analysis of Two Brucella Attenuated Vaccine Infecting Mouse Macrophagocyte

The experiment was conducted to discuss the difference of binding time of green fluorescent protein B.melitensis M5 (GFP-M5) and B.abortus S19 (GFP-S19) infecting the mouse macrophagocyte (RAW264.7),lysosome,endoplasmic reticulum and golgi body in the initial stage and compare the binding rate of GFP-M5,GFP-S19 with organelle in different timeline,respectively,by confocal laser scanning microscope (CLSM) and flow cytometry.The result showed that GFP-M5 and GFP-S19 were successfully constructed.The intracellular survival ability of Brucella M5,Brucella S19,GFP-M5 and GFP-S19 were not obvisouly affected after infecting RAW264.7.GFP-M5 and GFP-S19 could enter the macrophagocyte in 30 mins,and in 2 h the Brucella could reach lysosome,endoplasmic reticulum and golgi body.In addition,the binding time for two attenuated vaccine did not show differences in 1,2,3 and 4 h.The content of GFP⁺ cell produced by RAW264.7 infected by GFP-M5 and GFP-S19 did not show significant differences (P>0.05).Therefore,the two strains did not have significant differences in the invasion ability in the initial stage of infecting host cell.     

Effect of prostaglandin F2alpha on ovarian, adrenal, and pituitary hormones and on luteal blood flow in mares

The effect of a single injection of prostaglandin F2alpha (PGF) during mid-diestrus on systemic concentrations of progesterone, LH, FSH, estradiol, and cortisol and on blood flow to the corpus luteum was studied in 10 controls and 10 PGF-treated mares. Blood flow was assessed by estimating the percentage of corpus luteum with color-Doppler signals of blood flow during real-time scanning of the entire structure and by the diameter of the vascular pedicle near its attachment to the ovary. Treatment was done 8 days after ovulation and 0 h was immediately before the treatment. Examinations and collection of blood samples were done at 0 h, every 5 min until 1h, and then at 1.5, 2, 4, 8, 12, 24, 48, and 72 h. The concentrations of estradiol did not change, but progesterone, LH, FSH, and cortisol increased significantly within 5 min. Concentrations of LH and FSH in the PGF group remained elevated until a temporarily lower concentration at 8 or 4h, respectively, rebounded to 12h, and then slowly decreased. Cortisol remained elevated, until a decrease between 1 and 4h. Progesterone in the PGF group increased significantly until 10 min after 0 h and then decreased by 40 min to below the concentrations in controls. Within the PGF group, progesterone decreased significantly by 45 min to below the concentrations at 0 h. The values for each of the two indicators of blood flow did not differ significantly between the PGF and control groups until a decrease at 24h in the PGF group. Results did not support the hypothesis that the immediate transient post-PGF increase in progesterone was associated with an increase in luteal blood flow. Luteolysis, as indicated by decreasing progesterone, began well before the beginning of a decrease in luteal blood flow.