Image processing in remote sensing data analysis: The state of the art

Image analysis techniques applicable to remote sensing data are reviewed, with emphasis on recent developments. The topics covered include image modelling, feature detection, segmentation and classification, texture analysis, and matching.     

Deterministic generation of singlet state of N atoms in coupled cavities via adiabatic passage of a dark state

In this paper, we propose an efficient scheme to generate the N-atom singlet state via adiabatic passage of a dark state in cavity quantum electrodynamics (QED) system. Appropriate Rabi frequencies of the classical fields are selected to realize the present scheme. We discuss the influence of decoherence induced by cavity decay and atomic spontaneous emission by numerical calculation. The result shows that the scheme is insensitive to atomic spontaneous emission as the atomic excited state is hardly populated in adiabatic evolution.     

Preparation of tetragonal zirconia powders by a solid state reaction: Kinetics, phases and morphology

Powders of tetragonal (t)ZrO₂ have been prepared by a solid state reaction between sodium metazirconate and sodium metaphosphate. The reaction temperatures and times have been varied between 450 and 550°C and 5 and 75 h, respectively. Zirconia powder, mostly in thet andt′ phases, is obtained. The yield of ZrO₂ powder increases monotonically with time at all reaction temperatures according to a phase boundary controlled kinetics. The fraction oft phase also increases with time at 450°C and 500°C but goes through a maximum at 550°C, the highest temperature employed. A maximum of 55% of the precursor monoclinic zirconia (used to prepare sodium meta zirconate) is converted tot phase at 500°C/75 h. The ZrO₂ powder consists of crystallites of size 9–25 nm agglomerated into particles having average size between 2 and 4μm. The agglomerates have a breaking strength of 100 MPa. A hydrothermal treatment is found to break the agglomerates into smaller sizes. Grinding the powder in a mortar and pestle converts only 12% of thet phase into monoclinic, indicating that substantial fraction of the tetragonal phase is the non transformable varietyt′. Heating experiments also confirm this.     

纳米晶Ti(C,N)固溶体粉末的制备及组织结构研究

研究了纳米晶Ti(C,N)固溶体粉末的碳热还原反应制备及其组织结构特征。结果表明．以球形亚微米TiO2粉末和纳米碳黑为原料，通过原料成分C／Ti的准确配比和适当的工艺参数，可制备出成分优良的晶粒度为37nm的单相纳米晶Ti(C，N)固溶体粉末。     

固相反应法制备纳米铈锆复合氧化物

以碳酸铈、碳酸锆、草酸为原料,机械力促进固相反应法制备了纳米级铈锆复合氧化物(CexZr1-XO2)。用TGDSC分析前驱体的热分解温度,通过XRD、TEM、BET等测试手段对产物进行了表征。结果表明:所得产物为单一的立方晶系固溶体,平均粒径<40nm,比表面积达98m2/g。采用中低温固相反应法制备纳米级铈锆复合氧化物无需溶剂,无废液且节能。     

中空纤维微滤膜组件静态操作时过滤通量预测的实验研究

对中空纤维微滤膜组件在静态操作下处理酱油时过滤通量的预测进行了研究 .并从Ruth方程式出发 ,结合静态过滤的特点推导出了简单实用的过滤通量预测公式 .     

氟化石墨烯的制备研究进展

新型碳材料氟化石墨烯以独特的物理、化学性能受到广泛关注,在众多领域具有广阔的应用前景。综述了氟化石墨烯的制备方法,主要介绍以氟化石墨为原料的物理剥离法、使用不同溶剂作为插层剂的化学制备方法,以及以氧化石墨烯、石墨烯作为原料的制备方法,总结了各种制备方法的优缺点,并对未来氟化石墨烯的发展前景进行了展望。     

遥感影像在地外文明探索中发挥作用

六十年代以来,已向月球和水星、金星、火星、木星、土星、天王星,海王星等太阳系行星发去数十个空间遥感器,并已向地球上的地面站发回大量信息,使科学家们得以发现很多有趣的事物,显示为地球外生物高度文明的作为。本文着重介绍了在月球上发现的异常景物,显示可能在多年以前,曾有高度文明的生物在月球着陆。     

梯形聚苯基倍半硅氧烷的新型制备方法

以苯基三氯硅烷为原料,利用经过改良的热平衡缩合法,得到产物梯形聚苯基倍半硅氧烷(Ph-T)。借助傅立叶红外、X射线衍射和核磁共振硅谱等方法,确定了产物具有规整的梯形分子结构;以热重分析测定了其耐热性,在空气中失重5%时温度为530℃,具有优良的耐热性能。     

偏硅酸钙中Pr3+的4f5d态的光谱性质

高温下合成了掺Pr^3＋的CaSiO3,研究了Pr^3＋在室温下的发射光谱和激光谱,观测到Pr^3＋的4f5d态的两上能级,其最低能级向4f^2组态的^3H4,^3H6和^1G4发生辐射跃迁,其中以向^3H4的跃迁最强,而向^3Po和^1D2的无辐射跃迁几率可以忽略,从而得到了一种在短波紫外发光效率很高的新型材料。     

碳纳米管对中间相炭微球制备的影响

以中温煤沥青和碳纳米管为原料进行热缩聚反应,制备出含有碳纳米管的中间相炭微球,采用扫描电子显微镜(SEM)、激光粒度仪和X射线衍射(XRD)等分析手段对其形貌及结构进行了表征。研究了添加碳纳米管对中间相炭微球形貌、粒径、产率、微晶结构及热缩聚工艺的影响。结果表明添加碳纳米管能够促进小球成核,阻止小球的融并长大,使炭微球的粒径减小,分布均匀,但过多的碳纳米管会导致球形度变差及中间相沥青产率的降低;碳纳米管的存在使石墨片层尺寸减小,石墨化程度降低;碳纳米管经过酸煮处理后,可以获得球形度更好、含有更大比例碳纳米管的中间相炭微球。     

羟基磷灰石生物陶瓷材料的制备及其新进展

羟基磷灰石常用作医用生物陶瓷材料。本文对羟基磷灰石及其复合生物陶瓷材料的各种制备方法进行了概述和评论．重点介绍了羟基磷灰石制备方法的新进展．并对未来的发展前景进行了分析。     

有机磷农药残留前处理技术的研究

本实验主要是利用固相萃取技术对食品中有机磷农药前处理方法进行了研究。对自制的固相萃取小柱的选择参数进行了优化,建立合适的样品提取、净化、浓缩的前处理方法,确保色谱分析测定时无样品基质的干扰,从而为测定的结果提供了保证,并延长色谱柱的寿命,降低了实验成本。茶叶样品以丙酮为提取剂,超声波30 min后,经florisil柱(1000mg)+活性炭(50mg)混合柱浓缩净化,用10 mL的乙酸乙酯淋洗后,经色谱分析验证,所得回收率在73.7%以上,RSD在4.1%以下,结果令人满意。     

纳米BiVO4黄色颜料的制备研究

以Bi（NO3）3·2H2O和NaVO3为原料，采用液相沉淀法，制备BiVO4纳米材料。研究了反应温度和pH值对结果的影响。采用X射线衍射（XRD）、透射电子显微镜（TEM）和红外光谱（IR）技术对产物进行分析表征。结果表明，反应温度和pH值显著影响产物的结晶性和形貌结构，随着反应温度的逐步升高，产物的结晶性越来越好，而且物相趋向于单一的单斜晶系白钨矿结构。在相同的反应温度下，随着溶液pH的增大，产物由片状趋向干增厚的块状。     

聚乙烯醇复合膜的制备

以亲水性的聚乙烯醇为原料,采用机械涂敷法制备复合纳滤膜．考查了基膜、聚乙烯醇的浓度、交联剂的浓度及配比、涂层厚度、交联时间以及热处理等对膜分离性能的影响,确定了最终制备条件．在一定的温度和湿度条件下,在截留相对分子质量为100000的基膜上,通过5％的聚乙烯醇溶液与1％的戊二醛的交联反应,研制了截留相对分子质量为600的PVA复合纳滤膜。     

硝酸盐PAD法快速制备YBCO超导薄膜研究

用硝酸盐高分子辅助沉积法(简称PAD)来制备YB2C3O7-x(YBCO)超导薄膜,有着制备速度快、工艺简单和无环境污染等优点。采用硝酸盐水相前驱液,并加入高分子螯合剂和薄膜改性剂,然后将前驱液涂覆在LaAlO3(LAO)单基晶片上,采用快速低温分解,再经过高温烧结制备出完整的YBCO超导薄膜。在1.0×10-4 O2/N2气氛下制备的YBCO超导薄膜致密,YBCO(00l)峰取向明显,没有其它杂相峰,同时,转变起始温度TC=91K,转变宽度ΔTC=2K;在77K、自场下临界电流密度JC为约1MA/cm2。实验结果表明,采用硝酸盐PAD法的低温分解时间比传统的TFA-MOD法缩短9h左右,而且制备出的YBCO超导薄膜性能优良,该方法为以后的长带生产提供了一种新的制备技术。     

BaTiO3多晶陶瓷表面态研究

文中系统地对BaTiO3陶瓷的表面态进行综述,认为表面态确实是PTC效应产生的根源所在,同时对表面态的组成（主要对表面态中金属阳离子空位,氧空位）、微量3d元素对表面受主态的显著影响以及表面必度的定量计算三方面进行分析,认为表面态研究的难点在于其组成的复杂性,认为用电介质理论定量计算表面态密度存在粗略性问题,同时对表面态的研究前景进行展望。     

一种高效制备河豚毒素(TTX)方法的研究

为了获得大量高纯度的河豚毒素TTX,利用D201大孔树脂层析、超滤、离子交换层析、分子筛层析、反相制备液相色谱等方法,从假睛东方鲀(Fugu pseudommus)肝脏中分离纯化得到TTX晶体,得率为81．1％。获得的TTX晶体利用电喷雾电离质谱(ESI—MS)及核磁共振谱(NMR)进行结构验证,用高效液相色谱(HPIE)进行纯度分析定量,其纯度为99．5％。     

A Generalized Model for the Thermodynamic Properties of Mixtures

A mixture model explicit in Helmholtz energy has been developed which is capable of predicting thermodynamic properties of mixtures containing nitrogen, argon, oxygen, carbon dioxide, methane, ethane, propane, n-butane, i-butane, R-32, R-125, R-134a, and R-152a within the estimated accuracy of available experimental data. The Helmholtz energy of the mixture is the sum of the ideal gas contribution, the compressibility (or real gas) contribution, and the contribution from mixing. The contribution from mixing is given by a single generalized equation which is applied to all mixtures studied in this work. The independent variables are the density, temperature, and composition. The model may be used to calculate the thermodynamic properties of mixtures at various compositions including dew and bubble point properties and critical points. It incorporates accurate published equations of state for each pure fluid. The estimated accuracy of calculated properties is ±0.2% in density, ±0.1 % in the speed of sound at pressures below 10 MPa, ±0.5% in the speed of sound for pressures above 10 MPa, and ±1% in heat capacities. In the region from 250 to 350 K at pressures up to 30 MPa, calculated densities are within ±0.1 % for most gaseous phase mixtures. For binary mixtures where the critical point temperatures of the pure fluid constituents are within 100 K of each other, calculated bubble point pressures are generally accurate to within ±1 to 2%. For mixtures with critical points further apart, calculated bubble point pressures are generally accurate to within ±5 to 10%.     

软包锂电池铝塑复合膜制作工艺途径

本文介绍了软包锂离子电池铝塑复合膜的典型结构及制作工艺途径与产品质量指标,并简要论述市场需求前景。