140 research outputs found
Design and measurements of the high gradient accelerating structures
The purpose of this thesis was to study on design and measurements of the high gradient accelerating structures. After introducing the main parameters to characterize Linacs we explained the application of the periodic accelerating structure. Then we studied TW accelerating structure operating at K-band frequency in order to linearize longitudinal space phase to increase beam brightness in the framework of the Compact Light XLS project in order to produce hard x-ray. We estimated group velocity as a function of frequency both analytically and numerically. Analytical results have a good agreement with the numerical results. The main parameters such as shunt impedance, quality factor (Geometric factor) and R/Q independently from the operating frequency for the TM010, TM110 and TM011 for a single cylindrical “pill-box” have been determined analytically as they provide accurate model for the accelerating structures.
In order to characterize a normal conducting high accelerating structure with maximum gradients operating at X-band with extremely low probability of RF breakdown, an electroformed SW structures has been fabricated and characterized by SLAC and INFN with collaboration of other institute around the world at 11.424 GHz, coated with Au-Ni. We designed a gold plate RF high gradient structure operating at the X- band coated with Au-Ni. Bench measurements have been performed in the Department of SBAI of the University of Rome “La Sapienza”. The Slater method for the SW cavity has been employed in order to quantify the electric field inside the structure. Comparing the results with the results exposed from HFSS we report the features that have been quantified, showing good agreement. We continued working on the perturbation effect due to the aperture coupled between a waveguide and a cavity but for our application in SW multi-cell high gradient accelerating structure we studied on theoretical approach for reflection coefficient calculation in a SW cavity coupled to a waveguide. One method was based on circuit theory in which we found the overall Q of a resonant circuit for a cavity coupled to an external waveguide containing the RF generator. Q calculation led to the determining of the shunt impedance and consequently the reflection coefficient calculation. Comparison of the results shows a good agreement with the numerical results carried out by using the numerical code, HFSS. Another method of reflection coefficient calculation has been accomplished. We applied the modified Bethe’s theory presented by Collin and developed by De santis, Mostacci and L.Palumbo for TM01 mode cavities coupled by a small hole with a thickness size comparable to the wavelength. The amplitudes of forward and backward waves due to polarizabilites have been determined and we found equations for reflection and transmission coefficients. We demonstrated that our equation for reflection coefficient calculation is an analogous of the reflection coefficient obtained by Collin for TE10 using the circuit theory
Extraction of insecticidal toosendanin from meliaceae by supercritical CO_2
王宏涛(1968-),男,博士,副教授,主要研究方向为天然产物的提取分离等, E-mail: [email protected]。[中文文摘]苦楝素是楝科植物中制备植物源农药的主要杀虫成分。针对不同种源楝树的皮、叶及果实,采用溶剂浸提法提取筛选苦楝素含量较高的种源作为实验原料,采用乙醇提取,考察液固质量比、提取时间和提取次数等参数对苦楝素提取率的影响。当液固质量比为25∶1、提取时间为4 h、提取次数为3次时,苦楝素的提取率达18%。进一步采用超临界CO2萃取考察压力、温度、萃取时间、原料粒径和夹带剂等参数对苦楝素萃取率的影响,当温度为40℃、压力为20 MPa、时间为2.0 h、原料粒径为40目、夹带剂乙醇质量为CO2质量的12.5%时,苦楝素的萃取率达43.5%。在对萃取液结晶纯化中成功分离得到质量分数达98%的苦楝素。[英文文摘]Toosendanin is the main insecticidal component of meliaceae plants for producing botanical insecticides.The extraction of toosendanin from the parks,leaves and fruits of the various meliaceae plants was studied by using ethanol,and the part of the meliaceae plants with the maximal mass fraction of toosendanin was selected as experimental materials.The effects of the mass ratio of liquid to solid,extraction time,and extraction times on the yield of toosendan were investigated by using ethanol extraction method. The yield of toosendanin is up to 18% at them ass ratio of liquid to so lid of 25:1, extraction time of 4h and extract ing 3 times. The effects of pressure,
temperature, extraction time, and the partic le size of materials and the dosage of mod if iers on the yield of
toosendanin w ere investigated bym eans of supercritical CO2 extraction. The yield of toosendan in is up to 43.5% when ethanol is used as mod ifier with its mass 12.5% of CO2 mass at temperature 40,pressure 20 MPa,extraction time 2h and material particle size 40 mesh. The toosendanin crystal with mass fraction 98% was separated from the extracts by using crystalliza tionm ethod.福建省新世纪人才支持计划项
The Effects of Benzo [a] Pyrene (BaP) Exposure on the CYP1A1 mRNA and AhR2 mRNA Expression of Red Seabream(Pagrus major)
通过水体暴露方式对海水养殖真鲷进行bAP持续染毒,利用实时定量PCr技术研究了真鲷细胞色素P450基因(CyP1A1)和芳香烃受体基因(AHr2)随bAP暴露剂量、时间的动力学变化。结果发现,0.1~1.5μg/l环境浓度的bAP能够显著性诱导CyP1A1基因和AHr2基因的表达,且AHr2 MrnA早于CyP1A1 MrnA被诱导表达;bAP持续暴露48 H,CyP1A1和AHr2基因的表达水平均随暴露时间的延长而显著升高,染毒72 H后又回复到本底水平,实验表明这两个基因的表达与bAP的暴露剂量和暴露时间之间具有显著性的剂量-效应和时间-效应关系。The gene expression patterns of CYP1A1 and Aryl hydrocarbon receptor(AhR2) of red seabream(Pagrus major) were both measured using real-time quantitative PCR(qPCR) when fish exposed to environmentally relevant concentration of BaP(0.1,0.5 and 1.0 μg/L,respectively).The results showed that CYP1A1 mRNA and AhR2 mRNA could be induced significantly,besides,the time of AhR2 mRNA induced ahead of the time of CYP1A mRNA induced.The two genes were induced markedly at the begining of BaP exposure,and then decreased to the basal levels after 72 h.The results demonstrate that BaP can regulate CYP1A1 and AhR2 transcript in a dose and time dependent manner.国家“863”计划重点资助项目(2007AA091406);国家自然科学基金资助项目(30770391
Preparation of Tripalmitin Micronization by Supercritical Fluids Technique
利用气体饱和溶液微粒形成技术实验装置,分别用超临界n2和超临界CO2制备三棕榈酸甘油酯微粒,探讨压力、温度以及喷嘴大小等工艺参数对微粒(粒径、粒径分布和形貌)的影响。结果表明:n2辅助过程得到的微粒基本为球状;预膨胀压力越高,粒径越小,粒径分布越窄;100μM喷嘴下制得的微粒粒径最小,且分布较均匀。CO2辅助过程得到的微粒部分为球状,部分为针状和片状;预膨胀压力越高,粒径越小,粒径分布越窄;喷嘴直径大小对微粒平均粒径及粒径分布影响不大;预膨胀温度升高,颗粒的粒径稍微增大。CO2辅助过程得到的微粒粒径比n2辅助过程得到的微粒粒径稍大,但两者的粒径分布相差不大。Generation of tripalmitin microparticles from its melts was investigated by using both supercritical CO2 and supercritical N2.The effects of various operating conditions,such as the pre-expansion pressure,pre-expansion temperature,and nozzle size on the particle morphology,particle size and particle size distribution(PSD) were investigated.Results showed that microspheres were obtained from the N2-assisted process,the particle size decreased and PSD narrowed with the increasing of the pre-expansion pressure,nozzle size showed no obvious effect on the microparticles,and pre-expansion temperature should be less than 72 ℃ to obtain solid particles.From the CO2-assited process,spherical,lamellate and needle-like particles were obtained,the particle size decreased,PSD narrowed with the increasing of the pre-expansion pressure,nozzle size showed no obvious effect on the particles and the pre-expansion temperature slightly increased the average size of particles.Particles' PSD from supercritical CO2 was close to that from supercritical N2
Separation and identification of auraptene from grapefruit peel oil
橙油素是广泛存在于柑橘类果实中的天然抗癌活性成分。选用SP70大孔吸附树脂分离纯化葡萄柚精油中的橙油素,该树脂对于橙油素的吸附容量和解吸率分别达到14.53 Mg/g和83.32%,并成功地从树脂床层的洗脱液中结晶分离出橙油素晶体。对所得晶体分别采用差示扫描量热仪(dSC)、紫外吸收光谱(uV)、红外吸收光谱(Ir)、电喷雾质谱(ESI-MS)进行定性分析,分析结果与橙油素标准品相符合。进一步采用高效液相色谱(HPlC)对所得晶体进行定量分析,结果表明所得晶体中橙油素的质量分数可达85%。Auraptene exists widely in the peels and juice sacs of citrus species and is reported to be an effective inhibitor of chemical carcinogenesis in some rodent models.The separation and purification of auraptene from the grapefruit peel oil was performed by SP70 macroporous resin adsorption.The amount adsorbed and the recovery of auraptene were 14.53 mg/g and 83.32% respectively.Auraptene was crystallized out from the concentrated eluate of macroporous resin bed successfully.Differential scanning calorimetric(DSC),ultraviolet spectrum(UV),infrared spectroscopy(IR) and electrospray ionization mass spectroscopy(ESI-MS) were all used to analyze the obtained crystals qualitatively.The analytical results are in accordance with that of auraptene standard.Furthermore,high performance liquid chromatography(HPLC) was utilized to quantify auraptene of the crystals obtained.The mass fraction of auraptene in the obtained crystals can reach 85%.福建省新世纪人才支持项目(0000-X04157
Research progress in cigarette combustion model
综述国内外有关卷烟燃烧模型的研究进展。认为应在深入研究卷烟燃烧过程和机理的基础上,建立全面系统准确的卷烟燃烧数学模型,以便为工艺改进提供科学依据。Research progress in cigarette combustion model was reviewed.Suggestions were proposed that comprehensive,systematic and accurate mathematical model of cigarette combustion need to be established based on further research in combustion mechanism to improve blending technique
Removal of Iron During Copper Sulfate Production from Bioleaching Reextraction Solution
[中文文摘]利用三种方法分别对某铜矿山生物浸铜反萃液生产饲料级五水硫酸铜的重要步骤———除铁工艺进行了深入研究,结果表明:采用黄铵铁矾法除铁,控制温度在95℃、pH=1 6,除铁率可以达到91 2%;采用氢氧化铁沉淀法,于70℃,pH=3 8的条件下,除铁率可达98 1%。但上述方法除+、Na+和Ca2+等杂质带入硫酸铜溶液;采用一步结晶法,控制结晶温度在60℃、结铁过程会将NH4晶时间为6h,除铁率可以达98 5%,该工艺操作简单,产品符合饲料级硫酸铜的国家标准。[英文文摘]Iron removal is crucial to the process of feed-additive copper sulfate pentahydrate production from bioleaching reextraction solution.In this paper,three iron removal methods were examined.A series of experiments were conducted in different conditions and the results indicated that when iron was removed by precipitating in the form of ammonium jarosite(95 ℃,pH=1.6),the iron removal efficiency was 91.2%,while by precipitating in the form of ferric hydroxide(70 ℃,pH=3.8),the iron removal efficiency was 98.1% However ,by these two methods ,the use of oxidant and neutralization reagents introduced unwanted
NH+4 ,Na + ,Ca2 + into copper sulfate solution. Crystallizating copper sulfate from reextraction solution ,a simple
process ,could remove iron effectively without adding any additives and the iron removal efficiency could reach 98.5% under the condition of 60 ℃and 6 h ,and the quality of copper sulfate met national standards of feed additive.福建紫金矿业股份有限公司资助项
Studies on degradation mechanism of niclosamide ethanolamine salt Ⅰ Determination of niclosamide ethanolamine salt in photolysis solution
目的了解氯硝柳胺乙醇胺盐(nES)在水体中的光解规律。方法实验室配置PH5的0.05μg/Ml、PH7的0.5μg/Ml和PH9的2.5μg/MlnES溶液,采用氙灯光源作为模拟日光照射,照射后0、0.5、1、2、4、8、16、24、48、72、96H采集光解液,高效液相色谱法测定光解液中nES含量,同时设无光照对照试验,计算其半衰期。结果在氙灯光光照条件下,nES快速降解,8H3种PH值的nES溶液下降率分别为83.4%、78.8%和41.3%,24H下降率分别为92.1%、88.5%和95.8%。nESPH5半衰期为8.98H,PH7为10.34H,PH9为9.16H;无光照条件下放置12d溶液浓度稳定。结论nES可在水中快速光解。Objective To understand the photolysis mechanism of niclosamide ethanolamine salt(NES) in water body.Methods NES was formulated into solutions of pH 5(0.05 μg/ml),7(0.5 μg/ml) and 9(2.5 μg/ml),respectively.The xenon gas lamp was used as the simulated sunlight.After 0,0.5,1,2,4,8,16,24,48,72,96 h of the illumination,the photolysis solutions were collected to determine the amount of NES by using the high-performance liquid chromatography method(HPLC),and the experiment without illumination was also set as the control.The half-life was calculated.Results Under the illumination of xenon gas lamp,the NES degraded rapidly.The degradation rates were 83.4%,78.8% and 41.3%,respectively for 8 h,and 92.1%,88.5% and 95.8%,respectively for 24 h.The half-life of NES was 8.98 h for pH 5,10.34 h for pH 7,9.16 h for pH 9.The solution could keep stable for 12 d without illumination.Conclusion Photolysis of NES can occur quickly in water.江苏省自然科学基金(BK200602
Mirk/Dyrk1b在上皮性卵巢癌组织中的表达及意义
目的:探讨Mirk/Dryk1b(Minibrain-related kinase/Dual specificity tyrosine-phosphorylation-regulated kinase1B)在卵巢组织中的表达及其临床意义。方法:利用免疫组化检测Mirk/Dyrk1b在30例上皮性卵巢癌、20例上皮性卵巢囊腺瘤、10例正常卵巢组织中的表达。结果:Dyrk1b在上皮性卵巢癌中的表达明显高于上皮性卵巢囊腺瘤及正常卵巢组织(P0.05)。结论:Dyrk1b在上皮性卵巢癌中高表达,提示其可能参与了肿瘤的发生和发展,并有望成为临床早期诊断的肿瘤标志物和新的卵巢癌治疗的靶基因
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