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1.
超声波原油破乳脱水的声场参数实验研究   总被引:17,自引:0,他引:17       下载免费PDF全文
虞建业  袁萍  俞力 《应用声学》2001,20(3):27-30
本文阐明了超声波原油破乳脱水基本原理,实验研究了超声场参数对脱水率的影响,其中,声强,辐照时间和频率和影响原油脱水率的主要因素,而间歇比,脉冲宽度为次要回素,对本实验系统而言,声场参数有一个最佳值或范围,声强0.65W/cm^2,频率20kHz,间歇比8,脉冲宽度9.7ms,辐照时间5-10min.  相似文献
2.
LiNO3 was used as a shield in the preparation of single crystalline ZnO particles by a spray pyrolysis process in order to prevent agglomeration and enhance the crystallinity of the ZnO. LiNO3 was added to a precursor solution of zinc acetate dihydrate prior to its atomization by means of an ultrasonic transducer. Agglomerate-free particles having a mean particle size of 26 nm were successfully obtained after washing the product. X-ray diffractometry, field-emission scanning electron micrograph and transmission electron micrograph data indicate that the size and morphology of ZnO were strongly influenced by the operating temperature used and the residence time of the particle in the reactor.  相似文献
3.
Removing very fine particles in the 0.01-1 micro m range generated in diesel combustion is important for air pollution abatement because of the impact such particles have on the environment. By forming larger particles, acoustic agglomeration of submicron particles is presented as a promising process for enhancing the efficiency of the current filtration systems for particle removal. Nevertheless, some authors have pointed out that acoustic agglomeration is much more efficient for larger particles than for smaller particles. This paper studies the effect of humidity on the acoustic agglomeration of diesel exhausts particles in the nanometer size range at 21 kHz. For the agglomeration tests, the experimental facility basically consists of a pilot scale plant with a diesel engine, an ultrasonic agglomeration chamber a dilution system, a nozzle atomizer, and an aerosol sampling and measuring station. The effect of the ultrasonic treatment, generated by a linear array of four high-power stepped-plate transducers on fumes at flow rates of 900 Nm(3)/h, was a small reduction in the number concentration of particles at the outlet of the chamber. However, the presence of humidity raised the agglomeration rate by decreasing the number particle concentration by up to 56%. A numerical study of the agglomeration process as a linear combination of the orthokinetic and hydrodynamic agglomeration coefficients resulting from mutual radiation pressure also found that acoustic agglomeration was enhanced by humidity. Both results confirm the benefit of using high-power ultrasound together with humidity to enhance the agglomeration of particles much smaller than 1 micro m.  相似文献
4.
随机分布烟尘簇团粒子缪勒矩阵的数值计算   总被引:6,自引:0,他引:6       下载免费PDF全文
类成新  张化福  刘汉法 《物理学报》2009,58(10):7168-7175
利用蒙特卡罗方法根据团簇-团簇凝聚(CCA)模型对由球形原始粒子凝聚而成的烟尘簇团粒子进行了模拟,用离散偶极子近似(DDA)方法对随机分布的烟尘簇团粒子的缪勒矩阵元素进行了数值计算,给出了不同入射波长情况下随机分布烟尘簇团粒子的缪勒矩阵元素与组成簇团粒子的基本粒子的粒径和数目的数值关系,为进一步研究随机分布簇团粒子的形成机理、形态特性、散射特性提供了一种理论方法.  相似文献
5.
The synthesis of nanosized nickel colloids is investigated by using nickel chloride as the precursor, hydrazine as the reducing agent and palladium as the nucleation agent. High purity nickel can be obtained when the reaction temperature is above 80°C. At a lower reaction temperature, nickel hydroxide is also present in the precipitate form. Starting concentration of nickel ion is a dominant factor in affecting colloidal sizes, while other parameters such as reaction temperature and quantity of poly(vinyl pyrrolidone) (PVP) exhibit only minor effects. Although PVP has some dispersion power, it is not capable of preventing nickel colloids from gradual agglomeration. Our study shows that the subsequent addition of poly(acrylic acid) (PAA) after synthesis can help to stabilize the nickel suspension. This stabilized suspension can then be de-stabilized by changing pH to lower than 4 and vice versa. This reversible stabilization–de-stabilization process is likely due to the behaviour of PVP–PAA complex in the aqueous solutions.  相似文献
6.
纳米TiO2光催化剂防团聚的光谱研究   总被引:3,自引:0,他引:3  
本文用溶胶 凝胶过程超临界CO2 萃取制备纳米二氧化钛气凝胶 ,用FT Raman ,FTIR ,FS分别对初生态气凝胶粒子、在常态下以气凝胶形式保存了 36 0天的TiO2 纳米粒子及以初生态气凝胶的粉体保存了36 0天的TiO2 粒子进行表征 ,以光催化降解甲基橙为模型反应 ,结果表明 ,在常态下以气凝胶形式保存纳米TiO2 粒子能有效地防止由纳米TiO2 表面超亲水性引起粒子间的团聚 ,保持了初生态粒子的光催化活性。  相似文献
7.
随机取向烟尘团簇粒子的光学截面的数值计算   总被引:2,自引:2,他引:0       下载免费PDF全文
采用蒙特卡罗方法根据团簇—团簇凝聚(CCA)模型对由球形原始微粒凝聚而成的烟尘团簇粒子进行了模拟,利用离散偶极子近似(DDA)方法数值计算了不同原始微粒粒径和数目组成的随机取向的烟尘团簇粒子的总消光截面、吸收截面及散射截面等光学特性参数,研究了原始微粒粒径及数目对随机取向烟尘团簇粒子光学特性的影响。结果表明:当入射波长一定时,随机取向烟尘団簇粒子的光学特性主要取决于原始微粒的粒径和数目;烟尘团簇粒子对不同波段激光的吸收和散射存在差别,这种差别随原始微粒粒径及数目变化而变化。这一工作为研究电磁波在烟尘中的传输特性提供重要参考数据。  相似文献
8.
Nanoparticles of magnetite (Fe3O4) and hematite (α-Fe2O3) have been prepared by a simple microwave heating method using FeCl3, polyethylene glycol and N2H4·H2O. The amount of N2H4·H2O has an effect on the final phase of Fe3O4. The morphology of α-Fe2O3 was affected by the heating method. Crystalline α-Fe2O3 agglomerates were formed immediately at room temperature and most of these nanoparticles within agglomerates show the same orientation along [110] direction. After microwave heating, ellipsoidal α-Fe2O3 nanoparticles were formed following an oriented attachment mechanism. Both Fe3O4 and α-Fe2O3 nanoparticles exhibit a small hysteresis loop at room temperature.  相似文献
9.
黑井明代瓦条的拉曼光谱研究   总被引:1,自引:0,他引:1  
利用拉曼光谱并结合XRD和电子探针等技术分析发现 ,中国云南楚雄黑井明代瓦条的主要成分是SiO2 ,其中还含有月长石 (KAlSi3O8,属钾长石的变体 )、钠长石 (NaAlSi3O8)以及一种未知名矿物 (Al,Fe) 3(PO4 ,VO4 ) 2 (OH) 3·8H2 O等。月长石的存在 ,表明瓦条的烧结温度已高达 15 0 0℃ ,它说明云南明代陶器烧结工艺的技术已经达到了比较高的水平。此结果还显示了拉曼光谱所具有的独特优越性 :作为一种原位无损的检测技术 ,在辨别钾长石的变体———月长石方面 ,它具有简易性和可靠性 ,而其他技术却很难做到这一点 ;但拉曼光谱不能测出Fe的化合物存在 ,而电子探针和XRD能检测出Fe和Fe的化合物。文章表明 ,在科技考古中只有综合利用各种现代科技方法的优势 ,才能对古代文物作出比较全面的研究。  相似文献
10.
气固稀相流中颗粒沉积和聚集的分子动力学模拟   总被引:1,自引:0,他引:1  
本文在分子动力学模拟基础上采用了考虑黏附作用的JKR理论取代传统Hertz理论作为颗粒间作用力,并吸取了DEM中滑动摩擦、滚动摩擦和扭动摩擦的思想建立一种细颗粒碰撞和团聚过程的多时间尺度粒子动力学模拟方法.成功地实现了颗粒在纤维上沉积过程的模拟,结果表明微米颗粒的Van der Waala力量纲约是曳力2~10倍,中心流线附近颗粒更易于在纤维上沉积,初始沉积的颗粒则会在纤维上形成"遮挡"效应.  相似文献
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