Prenatal diagnosis of congenital epulis by three-dimensional ultrasound and magnetic resonance imaging

Congenital epulis is a benign intraoral tumor that has rarely been diagnosed prenatally. We report a fetus with congenital epulis diagnosed by three-dimensional (3-D) ultrasound and fetal magnetic resonance imaging (MRI) at 35 weeks' gestation. We show an image of congenital epulis using a new ultrasound technique, the 3-D multislice view, which shows images similar to CT or MRI. This is a short case report of congenital epulis diagnosed prenatally by 3-D ultrasound using multislice view and MRI. Copyright © 2006 John Wiley & Sons, Ltd.     

基于Skyline的流域河口生态安全评价三维场景实现技术

在总结了地学可视化发展过程及目前三维可视化技术研究进展的基础上,针对大洋河流域河口的地理特征设计并实现了三维可视化场景,为流域河口生态安全评价三维演示系统的实现奠定了基础,并从地表模型的建立、建筑物模型的建立和虚拟场景的搭建三方面详细介绍了流域河口三维场景实现的具体方法。     

基于三维一体的区域可持续发展指标体系构建理论

提出了基于三维一体的区域可持续发展指标体系模型。该指标体系反映了经济、环境、社会的整个过程 ,同时包含了压力、状态、响应模型。该区域可持续发展指标体系的建立为区域可持续发展评估指标的确立提供了依据     

Three- versus two-dimensional ultrasound for nuchal translucency thickness measurements: comparison of feasibility and levels of agreement

We have determined feasibility and levels of agreement for visualizing the nuchal translucency within a time limit with three-dimensional (3D) and two-dimensional (2D) transvaginal ultrasound. A total of 213 women of median gestational age 13 weeks (range 11–14 weeks) undergoing first-trimester nuchal translucency (NT) thickness measurements with 2D transabdominal ultrasound were included in the study. Additionally all women underwent 2D and 3D transvaginal NT examination within a time limit of 90 s. These two methods were compared with each other and with our standard method (2D transabdominal ultrasound) with respect to visualization of fetal nuchal fold and to the levels of agreement. The nuchal fold was visualized by 3D and 2D transvaginal ultrasound in 85.9% (95% CI: 80.5%, 90.3%) and 25.8% (95% CI: 20.1%, 32.2%), respectively (p<0.001). There was a statistically significant underestimation of the NT by 2D transabdominal as compared with 3D transvaginal ultrasound of 0.1 mm (p<0.001), and by 3D transvaginal as compared with 2D transvaginal ultrasound of even 0.1 mm (p<0.001). 3D transvaginal ultrasound of the nuchal fold has increased feasibility to 2D transvaginal ultrasound within a short examination time and with minimal, but significant, measurement differences. Copyright © 2001 John Wiley & Sons, Ltd.     

高架点源大气扩散的数值计算法

使用数值计算的方法来计算给定源强下的高架排放点源的浓度场分布情况。通过求解复杂地形上的大气热力———动力学方程组及扩散方程 ,建立了三维的风场、浓度场的数值模拟模式 ,并以云南开远电厂为例 ,对模式进行了验证。证明此方法可以成为解决复杂地形上大气污染扩散的实用方法。     

Prenatal sonographic appearance of Beare-Stevenson cutis gyrata syndrome: two- and three-dimensional ultrasonographic findings

Beare-Stevenson cutis gyrata syndrome is characterized by craniofacial anomalies, particularly craniosynostosis, ear defects, cutis gyrata, acanthosis nigricans, anogenit anomalies, skin tags, and prominent umbilical stump. The prenatal two- and three-dimensional ultrasonographic findings of this rare condition is reported. The detection was made at 32 weeks of gestation in a woman with polyhydramnios and fetal head anomaly. The ultrasound appearance and postnatal follow‒up are presented. Copyright © 2001 John Wiley & Sons, Ltd.     

光谱法研究胞外聚合物与四溴双酚A的相互作用

利用三维荧光光谱和红外光谱研究污水处理厂活性污泥中萃取的胞外聚合物与四溴双酚A之间的相互作用.结果显示,活性污泥胞外聚合物中存在3个明显的荧光峰,分别为,E_x/E_m=230/300nm(峰A)、E_x/E_m=240/350nm(峰B)和E_x/E_m=270/370nm(峰C).荧光滴定结果表明,3个荧光峰随着四溴双酚A 的加入均发生不同程度的猝灭.修正的Stern-Volmer模型和Ryan-Weber非线性模型计算胞外聚合物与四溴双酚A之间的结合常数,二者间的结合常数值(lg K)在4.23~6.27之间.红外光谱和同步荧光结果显示,胞外聚合物与四溴双酚A 结合导致胞外聚合物原有的蛋白质结构发生变化.同时,考察了不同环境条件(pH值、电导率以及离子)对两者作用的影响.结果表明:pH值和离子变化对胞外聚合物与四溴双酚A结合强度有影响,但电导率的变化影响并不显著.     

胶州湾COD、N、P污染物浓度数值模拟

在已建潮流模型的基础上，建立了胶州湾三维变边界污染物平流-扩散模型，模拟了胶州湾COD、N、P污染物现状浓度分布。结果表明，胶州湾主要污染因子为N，海湾东北部污染较为严重，东岸形成一条狭长的带状污染区，模拟结果与实测资料符合良好。本文统计了COD、N、P超标面积，N超一类水域面积为253km^2，占整个胶州湾面积的64％，COD和P大部分水域满足一类海水水质标准。模拟结果可为胶州湾水质管理、入海污染物总量控制提供依据。     

汕头港水域潮流运动的三维数值模拟

本文建立了汕头港水域的三维潮流数学模型，并采用交错网格（Ａｒａｋａｗａｃ）的差分方法求解，实际运用表明，该模型计算程序简单，计算结果合理，精度较好，模拟结果能较好地揭示计算区域内的潮流结构特征。     

Two- and three-dimensional ultrasound in malformations of the medullary canal: report of four cases

A comparison between two-dimensional (2D), and three-dimensional (3D) ultrasonography was made in four fetuses diagnosed with neural tube defect (NTD) in the first half of pregnancy. 3D ultrasonography (orthogonal and multiplanar systems) proved to be an excellent complement to 2D, particularly when using orthogonal planes. When using the 3D multiplanar surface imaging system, excellent images of the malformations can be rapidly obtained. Copyright © 2001 John Wiley & Sons, Ltd.     

Fenton法深度处理腈纶废水的特性

研究Fenton法深度处理难降解腈纶废水的影响因素及其优化反应条件,应用紫外和三维荧光光谱探讨腈纶废水生化出水中污染物的去除规律. 研究表明:初始pH由1.5升至6.0时,COD_Cr去除率由20.0%快速升至61.8%后再缓慢降至51.0%;c(Fe2+)由0.8 mmol/L增至10.8 mmol/L时,COD_Cr去除率先由2.5%增至58.0%再缓慢降至55.5%;c(H₂O₂)和反应时间对COD_Cr去除率影响较小. 正交试验极差表明,COD_Cr去除率的影响因素为初始pH>c(Fe2+)>c(H₂O₂)>反应时间,最优条件〔c(Fe2+)为7.20 mmol/L、c(H₂O₂)为0.16 mol/L、初始pH约为3、反应时间为90 min〕下腈纶废水生化出水ρ(COD_Cr)由308 mg/L降至103 mg/L,去除率为66.5%. 紫外和三维荧光光谱显示,腈纶废水生化出水中的类蛋白类物质完全被去除,大部分可见腐殖质类物质以及UV腐殖质类物质也被分解.      

苯酚三维荧光光谱特征参数影响因素的研究

用三维荧光光谱法研究了不同离子浓度,pH值对苯酚荧光光谱特征参数的影响,并探讨了腐殖酸对苯酚的荧光猝灭效应.结果表明,天然水中9种常见离子Na+、Mg2+、Ca2+、K+、NH4+、Cl-、HCO3-、SO42-、HPO42-对苯酚的荧光光谱形状和荧光强度基本无影响;NO3-的存在会使苯酚的荧光强度发生变化,荧光强度随着NO3-浓度增大而减小.苯酚在酸性和碱性条件下的存在形式不同,致使pH值对其荧光光谱特征参数影响较大:在酸性条件下,荧光强度基本保持不变;在碱性条件下,由于羟基的电离使荧光强度很弱.腐殖酸的存在使苯酚发生荧光猝灭,采用Stern-Volmer方程修正式对实验猝灭结果进行拟合,得到的拟合结果较好,相关系数为0.9995.     

Fe-Ni-TiO2/AC粒子电极的制备及可见光光电催化协同降解RhB

制备Fe-Ni-TiO2/AC粒子电极,应用于可见光助三维电极/电Fenton(Vis-3D/EF)光电催化体系中,以RhB为目标污染物,研究了可见光光电催化对RhB的协同降解.实验优化了Fe-Ni-TiO2/AC粒子电极的制备条件,并与活性炭粒子电极、活性炭负载TiO2粒子电极在Vis-3D/EF体系中的光电催化性能进行对比,结果表明:TiO2浸渍液浓度为2g/L,Fe-Ni掺杂比为5:5,Fe:Ni:TiO2物质的量比为0.5:0.5:100的条件下制备的粒子电极在Vis-3D/EF体系中表现出最优的光电催化性能,60min对RhB的去除率达92.58%,优于活性炭粒子电极和活性炭负载TiO2粒子电极.自制粒子电极在Vis-3D/EF体系比在3D/EF体系对RhB的去除率提高29.46%,表现出明显的光催化和三维电极/电Fenton协同处理效果,协同指数为1.18,说明了自制粒子电极应用在Vis-3D/EF组合技术中,实现对RhB的可见光光电协同降解是可行的.     

基于虚拟现实技术的大型储罐区灭火救援场景的构建

虚拟现实技术一直是信息领域研究、开发和应用的热点方向之一。它借助计算机构建出一个与现实环境十分逼真的虚拟环境,而且支持用户使用自然的技能亲身感受它。把虚拟现实技术作为一种崭新的训练方式和手段引入到消防领域中,具有广泛的应用前景和重要的现实意义。本文以石化企业大型储罐区灭火救援虚拟场区为研究对象,针对其场景复杂,规模较大,交互性要求高等特点,采用MultiGen Creato r/Vega开发平台,实现了石油化工火灾的灭火救援虚拟场景系统的建立,实现了场区的实时漫游和烟火特效。     

区域大气环境污染光学探测技术进展

环境污染物的形成、转化、输送和演变过程具有极强的时空相关性,研究和发展能适用于多组分环境污染物的快速、实时、动态监测技术是科学研究工作者面临的重大课题.基于光谱学原理的环境监测技术,由于其具有非接触、无采样、高灵敏度、大范围快速监测等特点,是国际上环境监测技术的主要发展方向之一,并被广泛应用于环境、气象和科学研究等领域.针对京津冀地区大气重污染发生-演变-消散全过程的核心科学问题,通过建立大气污染传输通道立体观测网,开展重污染时段和重污染过程的车载走航、机载观测地基遥感和卫星遥感观测,综合运用大气环境监测网以及超级站等观测平台,获取大气污染物的光学特性、环境气象信息等演变规律,从而推动京津冀及周边地区空气质量的持续改善.光谱学技术在环境监测领域的成功应用,为区域大气和全球环境状况奠定了技术基础.      

基于VRML的远程多媒体教学课件的研究与实现

针对目前远程教学中虚拟课件这一技术难点,结合当前网络技术的实际应用情况,提出了基于VRML技术实现远程教学课件的具体方案,介绍了VRML技术的工作模式、造型机制,以齿轮运动为例,着重讨论了三维建模和动态交互设计实现,指出了网上发布方法.     

First-trimester diagnosis of osteogenesis imperfecta associated with encephalocele by conventional and three-dimensional ultrasound

To illustrate the three-dimensional sonographic features of a rare genetic disorder, we report on prenatal diagnosis of osteogenesis imperfecta congenita associated with encephalocele at 13 weeks of gestation, using conventional and three-dimensional ultrasound. Because the parents were first-degree cousins and on the basis of the family history, a recessive autosomal inheritance was suspected. Of seven previous pregnancies, five were unaffected and two had been terminated in the second trimester owing to a similar abnormality (one affected boy and one affected girl). In the case we present, the diagnosis was made on the basis of two-dimensional ultrasound performed by physicians aware of the history; the quality of three-dimensional ultrasound imaging suggests that this technique might have contributed toward establishing a precise diagnosis in the absence of a positive family history. Besides, the global view provided by three-dimensional surface-rendering images made the parents more confident of the accuracy of the diagnosis. Although osteogenesis imperfecta congenita is generally considered as autosomal dominant, the case we report suggests that it may be inherited in a recessive autosomal fashion at least when associated with encephalocele. Three-dimensional ultrasound confirmed the conventional two-dimensional examination and was helpful in convincing the parents of the accuracy of the diagnosis. Copyright © 2003 John Wiley & Sons, Ltd.     

区域经济-污染-环境三维评价模型的构建与应用

为深入分析区域环境经济系统变化,在分析经济发展、环境污染、环境质量相互关系的理论基础上,构建了经济发展水平指数、环境污染指数、环境质量指数的三维立方体评价模型,划分了8个块区,分别表达低污染-低质量-低经济发展水平等8种状态,提出了模型的状态评价、发展阶段划分、演变趋势分析功能,以及相对含义、绝对含义评价途径和计算公式.以宁夏银川市为例检验模型,以广州市为目标参照区域进行了相对含义评价,该市1996~2010年内中长时段处于高污染-低质量-低经济发展水平状态,2007年以后转入了高污染-高质量-低经济发展水平,目前处于环境质量趋好、污染压力大、徘徊于环境低质量与高质量"拐点"附近状态.绝对含义评价结果:1996~2010年,该市始终处于高污染-低质量-低经济发展水平.研究表明,因目标参照区域选择和相关国家标准值等主要参数不同,使模型评价具有一定的弹性范围,无量纲的数据处理增强了指数耦合性,评价结果的空间可视化为环境管理决策提供了直接依据,改善了多指标模型评价结果抽象、数据口径不匹配、发展阶段划分不明确等问题,验证了该模型的应用合理性与适应性.     

三维电极电催化氧化处理邻氯苯胺废水的研究

文章用粉末状活性炭作为三维电极电化学反应器的粒子电极,选择石墨板和不锈钢板分别作为阳极和阴极,组成三维电极电化学反应器。文章研究了三维电极电化学反应器对邻氯苯胺废水的电催化氧化效果,探讨了槽电压、溶液初始pH、电解时间、支持电解质浓度、电极极板间距等影响因素对邻氯苯胺废水COD的去除效果。实验结果表明:当槽电压为15.0 V,溶液初始pH为3.0,支持电解质浓度为0.10 mol/L,极板间距为2 cm,电解时间为30 min时,邻氯苯胺废水的COD去除率达到97.50%。通过紫外-可见光光谱扫描发现,由于三维电极电催化氧化作用,邻氯苯胺的苯环断裂,生成一些脂肪族物质。谱图在250~350 nm波长范围内并无其他吸收峰出现,说明溶液在降解过程中并没有生成其他大分子物质。从而证实了三维电极电化学反应器对邻氯苯胺有很好的降解效果。