315 research outputs found
Numerical Simulation of the Nozzle with Self-Oscillating Flow Using the Vof Model
普通喷嘴喷出的水柱是直线型的,在普通喷嘴中加入倒u型和三角形结构,就能够使得喷嘴喷出来的水柱呈现振荡形式。利用多相流VOf(VOluME Of fluId)模型模拟内建振荡结构的喷嘴的喷射流动过程,Cfd仿真结果显示,喷嘴喷射的水柱呈现上下摆动的状态,和真实情况相吻合。The jet water shape of the nozzle will become a self-oscillating shape,if the triangle and U shape models are made into the normal nozzle.Using the Vof model,the jet shape of the nozzle will be simulated through a commercial CFD software FLUENT.The Vof model(Volume of Fluid) is a surface-tracking technique applied to a fixed Eulerian mesh.It is designed for two or more immiscible fluids where the position of the interface between the fluids is of interest.The CFD simulation results shows that the jet shape of the nozzle is oscillate in a fixed period
考虑分布式再生能源和储能的主动配电网可靠性评估
随着主动配电网技术的逐步发展和应用,针对主动配电网的各项评估技术也需要进一步研究。由于主动配电网在网络结构、潮流流向等方面与传统配电网有很大区别,因此针对主动配电网的评估方法也与传统配电网不同,提出了一种考虑分布式再生能源和储能的主动配电网可靠性评估方法。首先运用蒙特卡洛模拟法进行系统状态选择,再基于不同网络类型,采用改进的前推回代潮流计算方法进行潮流计算与潮流平衡调整,进而计算各项评估指标,获取综合评估值。通过对9个方案进行可靠性评估,验证了所提方法的有效性
Effect of the Construction of Green Belts on the Attenuation of Traffic Noise along the Urban Trunk Roads in Xiamen City
通过对厦门市主干道绿化带种类结构调查以及噪声测定等,分析了厦门市主干道绿化带结构及其减噪效果。结果表明,厦门市主干道绿化带可分为4种结构:单一乔木型、乔木+疏灌木/绿篱型、乔木+密灌木型以及乔木+小乔木+灌木/绿篱型,带宽多在4~10M。厦门市主干道绿化带总体减噪能力为0.93~12.96db,绿化带对交通噪声超标治理率达70%。绿化带减噪能力y(db)与带宽X(M)呈显著的线性关系:y=1.2251X+0.2416(r2=0.8603);绿化带的附加衰减与总衰减亦呈显著正相关:y=0.4535X+0.2698(r2=0.9242),噪声的附加衰减主要受绿化带结构的影响,上述四种结构对噪声附加衰减平均值分别达0.93、2.25、4.43和6.72db。绿化带的宽度和结构均是影响其减噪效果的关键因素。Through site investigation and noise monitoring, the effects of the construction of green belts along the urban trunk roads in Xiamen Island on the attenuation of noise has been studied.The results show that the construction of green belts along the trunk road can be divided into four kinds of types as bellows: type I, single arbor; type II, arbor + shrub; type III, arbor + sub-arbor and type Ⅳ, arbor + sub-arbor + shrub.Their width varied among 4--10 m.The noise-reducing ability (y, dB) of the green belts varied from 0.93 to 12.96 dB with various belt widths (x, m), and can be expressed as following: y=1.2251x+0.2416.Meanwhile the additive attenuation of traffic noise (y, dB) presents a closely linear relationship with the total noise-reducing ability (x, dB) as following: y=0.4535x+0.2698 (R2=0.9242).Meanwhile, the additive attenuation of traffic noise is main affected by the constructions of green belts, which reached 0.93, 2.25, 4.43 and 6.72 dB, respectively for the above four kinds of construction types.It shows that the width and construction of green belts play the same important role to reduce the traffic noise
诱导型一氧化氮合酶和血管内皮生长因子在舌癌细胞株中的表达
【目的】探讨诱导型一氧化氮合酶(iNOS)和血管内皮生长因子(VEGF)在舌鳞癌细胞株Tca8113中的表达,为进一步研究iNOS和VEGF在舌鳞癌肿瘤血管生成中的作用提供实验基础。【方法】采用逆转录-聚合酶链反应(RT-PCR)法和SP免疫组化方法,对舌鳞癌细胞株Tca8113中iNOS和VEGF mRNA和蛋白表达情况进行检测。【结果】RT-PCR检测到舌鳞癌Tca8113细胞株中iNOS/VEGF mRNA条带明显,SP免疫组化检测到iNOS/VEGF蛋白在舌癌细胞胞浆中呈强阳性表达。【结论】iNOS/VEGF mRNA和蛋白在舌鳞癌Tca8113细胞株中呈高水平表达
Study on organochlorine pesticide and PCBs at surface water in Xiamen Harbour
利用GC -ECD对厦门西港 1998年 7月取得的 9个站位表层水体中的 18种有机氯农药 (HCHs ,DDTs等 )和 12种多氯联苯 (PCBs)进行分析。其中有机氯农药的浓度范围 6 .6 0~ 32 .6ng/L(其中HCHs:3.5 1~ 2 7.8ng/L ,均值 8.5 7ng/L ;DDTs:0 .95~ 2 .2 5ng/L ,均值 1.45ng/L) ,多氯联苯的浓度为 0 .0 8~ 1.6 9ng/L ,同国内外其他港口海区相比较 ,其污染程度相对较低。同时 ,对有机氯污染的分析表明 ,发现近年来仍有有机氯的污染输入 ,其农药的使用主要集中在六六六和滴滴涕上 ;多氯联苯和有机氯农药在厦门西港有着相似的分布及来源特征。organochlorine pesticides and 12 polychlorinated biphenyls(PCBs) at the sruface water in Xiamen Harbour were determined. The range of organochlorine pesticides was 6.60~32.60 ng/L, and the PCBs concentrations were 0.08~1.69 ng/L. Compared with the results of other harbor and estuaries, it showed that the contamination for organic chlorine pollutants was more slight than those of others. At the same time, it was found that organochlorine pesticides and PCBs have the similar geological destribution and resources.福建省自然科学基金!项目 (D9810 0 0 3
Evaluation and Fate of the Organic Chlorine Pesticides at the Waters in Jiulong River Estuary
1999 0 6,对九龙江口 1 5个站位的表层水 ,1 3个站位的间隙水进行了 1 8种有机氯农药的测定结果表明 ,有机氯农药总含量在表层水中的浓度范围为 51 3~ 2 4 79ng L ;在间隙水中的浓度范围是 2 66~ 33355ng L .对不同有机氯的含量在各站位的分布特征进行了探讨 ,发现Methoxychlor(甲氧滴涕 ) ,EndosulfanSulfate(硫酸硫丹 ) ,Endrinaldehyde(乙醛异狄氏剂 )以及EndosulfanII(硫丹 ) ,Dieldrin(狄氏剂 ) ,Deta HCH和Beta HCH 7种有机氯农药在 1 8种有机氯农药中都占主要部分 ;九龙江口的六六六的含量顺序 :β >δ α >γ ;对于滴滴涕 ,表层水中的含量 :DDE DDD >DDT ;间隙水中的含量 :DDE DDT >DDD ,二者DDE的含量都在总DDTs的 50 %以上 ,说明环境中的DDTs主要降解为DDE ;九龙江口有机氯农药随着盐度梯度 ,在河口中呈去除趋势 ;且间隙水中有机氯农药比表层水中的浓度高 ,说明其倾向于吸附在沉积物颗粒上 ,其浓度差使得有机污染物可能通过再悬浮等过程从底层向上层迁移 .九龙江口的有机氯农药污染与其他港湾相比 ,污染水平相当 ,部分站位水质有机氯农药 (HCHs和DDTs)超过国家一类水质的标准 .Organochlorine Pesticides at the water(surface water and porewater) in Jiulong River Estuary were determined. The range of organochlorine pesticides at surface water was 51.3~2479ng/L, and the concentration in porewater was 266~33355ng/L. The results showed that the organochlorine pesticides were removed in the estuary and the sediments were the reservior of the organochlorine pesticides. Compared with the results of other harbor and estuaries , it showed that the contamination for organic chlorine pollutants in Jiulong River Estuary was similar to those of others. At the same time,the risk of organochlorine pesticides in the estuary was evaluated.1998年教育部重点项目、基金委资助留学人员短期回国工作讲学专项基金!项目联合资助 (4 9910 76 0 74
The trends and characteristics of organochlorines pollution in surface sediments of Xiamen Western Bay
利用GC ECD对厦门西港 1 998年 7月取得的 8个站位表层沉积物中的 1 8种有机氯农药 (HCHs,DDTs)等和 1 2种多氯联苯 (PCBs)进行分析 .其中有机氯农药的浓度范围ND(未检测出 )— 0 58ng/g(其中HCHs和DDTs的含量分别为ND—0 1 4ng/g与ND— 0 0 6ng/g) ,多氯联苯的浓度为ND— 0 32ng/g ,与 1 986、1 993年的厦门西港的分析结果相比较 ,污染程度明显降低 ;说明近年来的厦门的有机污染得到逐步控制 ,也与有机物随时间推移逐渐详解有关 ,分析表明多氯联苯和有机氯农药在厦门西港有着相似的分布特征 .The contents of 18 organochlorine pesticedes and 12 polychlorinated biphenyls(PCBs) in suface sediments from Xiamen Western Bay were analyzed by GC\|ECD. The range of organochlorine pesticides was ND—0 58?ng/g,and the PCBs were ND—0 32?ng/g.Compared with the results of Xiamen Harbor in 1986 and 1993, it showed that the pollution of organochlorines decreased gradually along the time, in Xiamen Harbor became and the contamination was more slightly than that of other Harbors or Estuaries. At the same time, it was found that the geological distributions of organochlorine pesticides and PCBs, also the HCHs and DDTs were similar to each other, which indicated that the polltion was cansed by a same source
Studies on chemical constituents in ethanolic extract from Acanthus ilicifolius as a pharmaceutic mangrove
目的探讨老鼠簕的化学成分。方法将老鼠簕全株粉碎后,用95%乙醇浸提3次,合并浓缩,浸膏的石油醚部位经反复硅胶柱层析分离,结合波谱学数据鉴定化合物结构。结果从石油醚部位分离得到8个化合物,分别为β-谷甾醇(Ⅰ)、豆甾醇(Ⅱ)、正十六烷酸(Ⅲ)、正二十八烷酸(Ⅳ)、4,22-二烯-3-酮豆甾烷(stig-masta-4,22-dien-3-one)(Ⅴ)、4-烯-3-酮豆甾烷(stigmast-4-en-3-one)(Ⅵ)、5,22-二烯-7-酮-3β-羟基豆甾烷(3β-hydroxystigmasta-5,22-dien-7-one)(Ⅶ)、2-唑啉酮(2-benzoxazolinone)(Ⅷ)。结论其中Ⅴ,Ⅵ,Ⅶ为首次从该植物中分离得到。Objective To study the chemical constituents of Acanthus ilicifolius.Methods The air-dried and powdered plant material was extracted with 95% ethanol.Silica gel and Sephadex LH-20 column chromotography were used in the isolation from the ethanol extracts of the whole plant,the compounds were determined on the basis of various modern spectroscopic analyses and physical constants.Results Eight compounds were isolated from the petroleum ether soluble portion,identified as β-sitosterol(Ⅰ),stigmasterol(Ⅱ),n-hexadecane acid(Ⅲ),n-octacosanic acid(Ⅳ),stigmasta-4,22-dien-3-one(Ⅴ),stigmasta-4-en-3-one(Ⅵ),3β-hydroxystigmasta-5,22-dien-7-one(Ⅶ) and 2-benzoxazolinone(Ⅷ).Conclusion CompoundⅤ,Ⅵ,Ⅶ were obtained from the genus for the first time.国家自然科学基金(30671646);; 福建省科技计划资助项目(2003Y036
Study of the GaN Film by Spectroscopic Ellipsometry
【中文摘要】 采用椭圆偏振光谱法,在1.50~6.50 eV光谱内,研究了在蓝宝石衬底(0001)面上使用金属有机化学气相沉积(MOCVD)的方法制备的非掺杂纤锌矿结构GaN薄膜的光学性质。建立GaN表面层/外延层/缓冲层/衬底四层物理结构模型。与Cauchy和Sellmeier色散公式比较后选择了Tanguy Extended色散公式来分析GaN薄膜的光学性质。椭圆偏振光谱拟合结果表明,Tanguy Extended色散公式能更准确、方便地描述GaN薄膜在全波段(特别是带隙及带隙之上波段)的色散关系。提供了GaN薄膜在1.50~6.50 eV光谱范围内的寻常光(o光)和非寻常光(e光)折射率和消光系数色散关系,为定量分析GaN薄膜带边附近各向异性的光学性质提供了依据。
【英文摘要】 Optical property of wurtzite GaN film was investigated by spectroscopic ellipsometry(SE) in the spectrum range of 1.50~6.50 eV.Unintentionally doped wurtzite GaN film was fabricated by metal-organic chemical vapor deposition(MOCVD) on(0001) sapphire.Four-layer physical structure model including surface layer,epilayer,buffer layer and substrate was built by analysis.Compared with common dispersion formulas such as Cauchy and Sellmeier,Tanguy Extended dispersion formulas was used to characterize optical prope...国家自然科学基金重点专项(60827004);国家自然科学基金(60776066);国家863计划项目资助项目(2011AA03A110
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