Measurement of properties of a smooth-walled spline-profile feed horn around 840 GHz

For astrophysical applications at submillimeter wavelengths, efficient coupling of the feed horn pattern in the focal plane to the radiation pattern of the telescope is paramount. To date, at 840 GHz with high band width, corrugated feed horns have been used with very good results. The goal of developing instruments for KOSMA above 1 THz where state-of-the-art heterodyne systems are still governed by receiver noise rather than by radiative background, requires fabrication of corrugated structures of the order of λ/3 or less. This is non-trivial, and here we present the performance of a smooth-walled spline-profile feed horn, which is considerably easier to manufacture compared to a corrugated feed horn. The performance is assessed via radiation patterns in H, E and 45° D-Plane in co- and cross-polarization.     

高效建立129S1/SvImJ 小鼠胚胎干细胞方法的探讨

选取超排后129S1/SvImJ品系小鼠的优质囊胚,使用辐照后冻存复苏的小鼠胚胎成纤维细胞作为饲养层,对比高浓度酶短时间消化法和低浓度酶长时间消化法,以0.25%胰酶-0.04%EDTA高浓度酶短时间消化法高效建立了4株小鼠胚胎干细胞系,建系率为36.31%.碱性磷酸酶,核型分析,体外分化和体内分化能力以及小鼠胚胎干细胞表面特异性分子标志0ct-4和Nanog的检测等表明,4个ES细胞系均为典型的小鼠胚胎干细胞系.所建立的ES细胞系为大规模培养ES细胞,进行后续的实验建立了理想的材料平台.     

畜牧养殖用料量检测系统设计与实现

针对国内目前畜牧养殖业饲料使用量大,但大吨位称重传感器价格较高、而且安装不方便、精度不高的问题,设计开发了一种畜牧养殖用料量检测系统;该系统多点采集用料量高度值,通过高度值间接计算出用料量体积,针对料塔内饲料密度不均衡性,通过三维拟合法估算不同高度对应的饲料密度系数,使用体积乘以密度计算出实时用料量;经实际验证,该系统检测用料量误差在3%以内。     

高效液相色谱-串联质谱法同时测定饲料中氯霉素、甲砜霉素与氟甲砜霉素残留量

建立了饲料中氯霉素(CAP)、甲砜霉素(TAP)、氟甲砜霉素(FF)3种抗生素残留量的高效液相色谱-串联质谱(HPLC-MS/MS)测定方法。样品经碱化乙酸乙酯提取,蒸发浓缩,提取物经正己烷脱脂,液-液分配净化后,采用电喷雾电离源(ESI)负离子多反应监测(MRM)模式检测,内标法定量。氯霉素、氟甲砜霉素和甲砜霉素的线性范围分别为0.2～10.0、0.2～10.0、1.0～50.0μg/L,相关系数(r2)不低于0.990 0;其检出限分别为0.1、0.1、0.5μg/kg,定量下限分别为0.3、0.3、1.5μg/kg。3种抗生素药物的平均回收率为77%～108%,相对标准偏差(RSD)不大于10.9%。     

Effect of Feed Composition Changing at Naphtha Catalytic Reforming Unit Due to Involvement of Gasoline Fraction Obtained by Diesel Fuels Hydrodewaxing into the Processing

One of the primary products of hydrodewaxing process is stable gasoline, which is characterized by low octane number on the one hand. On the other hand, it contains a significant amount of iso-paraffins (on average 45% wt.) and naphthenes (on average 25% wt.), which are reagents in the naphtha catalytic reforming process primary reactions. Feasibility of stable gasoline obtained by means of diesel fuel catalytic hydrodewaxing process involving into the processing at the naphtha catalytic reforming unit has been estimated using naphtha catalytic reforming mathematical model. Technological scheme of stable gasoline from hydrodewaxing unit supply to the reforming unit is presented. Naphtha catalytic reforming and diesel fuels hydrodewaxing processes resource efficiency increases by 15–20% due to rise in catalytic reforming feed source.     

Modeling of the RF system for the normal conducting linac

To study the new RF control methods, a mathematic model of the RF system for the normal conducting linac is built and implemented with the software of Matlab. The model contains some typical units of the RF system, such as the klystron, the SLED and the traveling wave accelerating tube. Finally, the model is used to study the working point of the SLED and the adaptive feed forward algorithm for the RF control system. Simulation shows that the model works well as expected.     

Determination of inorganic elements in animal feeds by NIRS technology and a fibre-optic probe

In the present work we study the use of near infra-red spectroscopy (NIRS) technology together with a remote reflectance fibre-optic probe for the analysis of the mineral composition of animal feeds. The method allows immediate control of the feeds without prior sample treatment or destruction through direct application of the fibre-optic probe on the sample.The regression method employed was modified partial least squares (MPLS). The calibration results obtained using forty samples of animal feeds allowed the determination of Fe, Mn, Ca, Na, K, P, Zn and Cu, with a standard error of prediction (SEP(C)) and a correlation coefficient (RSQ) of 0.129 and 0.859 for Fe; 0.175 and 0.816 for Mn; 5.470 and 0.927 for Ca; 2.717 and 0.862 for Na; 4.397 and 0.891 for K; 2.226 and 0.881 for P; 0.153 and 0.764 for Zn, and 0.095 and 0.918 for Cu, respectively.The robustness of the method was checked by applying it to 10 animal feeds samples of unknown mineral composition in the external validation.     

鳗鱼、饲料中恩诺沙星残留的测定及真假阳性辨别

采用反相高效液相色谱法(RP-HPLC),测定鳗鱼、饲料中的恩诺沙星药物残留．在Waters Nova-Pak C18柱上,用荧光检测器,激发波长280nm;发射波长450nm．流动相为5mmol／L NaH2PO4溶液-乙腈溶液(体积比为70：30),磷酸调pH值为2．7,流速1．2mL／min,柱温40℃．在鳗鱼、饲料中的最低检测限分别达到1μg／kg和2μg／kg,标准曲线在30—500ng／mL线性范围内相关系数达0．9997．在3种浓度水平对鳗鱼组织和饲料中的3种浓度进行回收率测定,其回收率在76％～98％之间;变异系数RSD小于8％,符合痕量测定要求．还对如何辨别真假阳性进行特别介绍．     

A high‐throughput screening method for determination of multi‐antibiotics in animal feed

A high‐throughput method based on ultrasonic‐assisted extraction, 96‐well plate thin‐film microextraction was established to determinate 18 antibiotics in animal feed. In this method, the extraction was implemented by ultrasonic‐assisted extraction for 30 min with disodium ethylenediaminetetraacetic acid‐McIlvaine buffer (pH 5) containing 6% sodium chloride w/v, purified by thin‐film microextraction and combined with 96‐well plate system to improve the efficiency. Optimization of thin‐film microextraction conditions was performed by methods of single factor and response surface, and finalized as: condition time: 20 min; adsorption time: 55 min; washing time: 5 s with water; desorption time: 30 min with acetonitrile/water (8:2, v/v) containing 0.1% formic acid v/v. Evaluation of different extractive phases showed that polystyrene‐divinylbenzene‐polyacrylonitrile was the optimum coating. The analysis was performed by ultra‐high performance liquid chromatography with tandem mass spectrometry. Recovery, inter‐ and intraday precision, linearity, limit of detection, and quantitation were evaluated. The average recoveries of 18 antibiotics were 66.6–93.5% at three spiked levels, intraday precision was 1–8.4%, and interday precision was 3.0–16.4%. The linearity was good for r² > 0.99. Limits of detection and quantification were found in the range of 1–14 and 4–48 µg/kg, respectively.