青海湖地区NCEP资料对风云二号C星热红外通道绝对辐射定标影响研究

为了分析大气廓线中温度和相对湿度变化对风云二号C星(FY-2C)热红外通道定标的影响,分别利用2005年6月25日青海湖场地定标试验的实际探空数据和对应时刻NCEP(美国国家环境预报中心)全球再分析大气廓线资料(简称NCEP资料)对FY-2C热红外通道进行定标计算,两种方法定标结果一致.利用2003年8月的14次青海湖实际探空数据和对应时刻的NCEP资料进行FY-2C热红外通道入瞳辐亮度和亮温的对比计算,利用辐射传输计算软件(MODTRAN 3.7)进行大气廓线对FY-2C热红外通道入瞳辐亮度和亮温的敏感性试验.计算结果表明对于青海湖地区,NCEP资料可用于FY-2C热红外通道的辐射定标计算.     

匹配滤波器组与FFT结合的伪码快速捕获方案研究

文中提出了部分匹配滤波器组与FFT相结合的伪码快速捕获的一种实现方案.该方案采用部分匹配滤波器组完成时域内完全并行搜索,同时采用128点FFT以实现频域的部分或完全并行搜索,以增加移位寄存器长度的较小代价去除大规模用以相干累加的SRAM,并且有效降低了FfT的工作时钟频率,便于硬件实现.该方案在一块FPGA上验证通过,并在0.18μm的CMOS的工艺下综合,电路规模是约合150.2万个晶体管,最高工作时钟频率是103MHz.该捕获方案最终等效于13.1万个串行相关器,极大提高了伪码的捕获速度.     

Enrichment of H(2)(17)O from tap water, characterization of the enriched water, and properties of several (17)O-labeled compounds

A low-abundance form of water, H(2)(17)O, was enriched from 0.04% to ～90% by slow evaporation and fractional distillation of tap water. The density and refractive index for H(2)(17)O are reported. Gas chromatography-mass spectrometry (GC-MS) of (16)O- and (17)O-1-hexanols and their trimethyl silyl ethers and of (16)O- and (17)O-hexamethyl disiloxanes was used to determine the percentage of (17)O enrichment in the H(2)(17)O. Furthermore, the chemical shifts of labeled and nonlabeled water dissolved in CDCl(3) differed sufficiently that we could verify the enrichment of H(2)(17)O. (17)O hexanol was synthesized by the reaction of iodohexane with Na(17)OH. (17)O-Labeled trimethylsilanol and (17)O-labeled hexamethyldisiloxane were prepared by the reaction of H(2)(17)O with bis(trimethylsilyl)trifluoroacetamide (BSTFA). To generate standards for (17)O NMR, H(2)(17)O(2), and (17)O camphor were prepared. H(2)(17)O was electrolyzed to form (17)O-labeled hydrogen peroxide which was quantified using two colorimetric assays. (17)O-Labeled camphor was prepared by exchanging the ketone oxygen of camphor using H(2)(17)O. The (17)O-labeled compounds were characterized using (17)O, (1)H, and (13)C NMR and GC-MS. While we were characterizing the labeled camphor, we also detected an unexpected oxygen exchange reaction of primary alcohols, catalyzed by electrophilic ketones such as camphor. The reaction is a displacement of the alcohol OH group by water. This is an example of the usefulness of (17)O NMR in the study of a reaction mechanism that has not been noticed previously.     

复合材料金相试验方法研究

分别采用常规黑白金相、彩色金相、微差干涉衬度试验方法对长纤维增强、短纤维增强、颗粒增强金属基复合材料显微组织进行了研究,结果表明:三种试验方法虽各有其自己的优缺点,但微差干涉衬度试验方法具有一定的优越性.     

打造小庭院的智慧

在通常的意识中,面积小的院子,很难设计得理想丰富,人们往往也就放弃了规划它的念头,任其自由生长着。其实不然。俗话说,麻雀虽小,五脏俱全。空间越小越应当合理地使用,发挥其空间的最大价值。这座可爱的小庭院是城市庭院设计的一个典型。庭院位于旧金山国家公园附近,是一座联排别墅的小后院。院子     

一种基于遗传算法的不等间距二维非周期阵面

目前大规模地基固态相控阵由于成本原因,普遍采用大单元间距以减少通道数。在这种间距下,可视空间会出现栅瓣效应,天线性能恶化,雷达扫描范围受限。对阵面设计方法进行研究,提出一种不等间距阵面优化方法。仿真结果表明,在λ×λ单元口径下,实现±20°的扫描角度内栅瓣低于-20 dB;由于阵面口径增大,阵面方向性增强,单元数减少18%。     

The erythropoietin response to the anemia of thermal injury

Erythropoietin excretion was persistently increased following major thermal injury in 4 of 5 patients. A good correlation was found between erythropoietin excretion and red cell mass but not between erythropoietin excretion and hematocrit. In spite of the increased erythropoietin, erythropoiesis in these thermally injured patients was inadequate to compensate for erythrocyte deficits as judged by bone marrow morphology, reticulocyte counts, and transfusion requirements.     

Cryoimmunoglobulin IgGk with microtubular ultrastructure associated with pyoderma gangrenosum

Based on the hitherto published population data of the human red cell PGM1 and acid phosphatase polymorphisms, the geographical distributions of their gene frequencies were analyzed. As far as the acid phosphatase alleles are concerned, a marked geographical gradient was found as the Pa and Pb alleles showed significant correlations with the mean annual temperatures of the various human biotopes (Pa:r = -0.706; Pb:r = +0.812). Against that, the world distribution of the PGM1 alleles did not show a comparable correlation (PGM1 1:R = +0.063; PGM2 1:R = -0.063). The possible reasons for the distribution pattern of the acid phosphatase alleles are discussed.     

Splenic imaging with 99mTc-labeled erythrocytes: a comparative study of cell-damaging methods

Several methods of damaging red blood cells (RBCs) for splenic imaging were compared to determine the optimum approach. The RBCs from donor animals were labeled with 99mTcO4- and damaged by heat, excess acid citrate dextrose (ACD), excess Sn(II) ion, or the sulfhydryl inhibitors N-ethylmaleimide (NEM) or p-hydroxymercuribenzoate (PMB). The organ distributions of undamaged and damaged RBCs were determined in rats, and splenic imaging studies were performed in rabbits. Splenic deposition and spleen-to-liver ratios with heat- or sulfhydryl-damaged 99mTc-RBCs were significantly greater (p less than 0.001) than the values obtained using ACD or Sn(II) ion. Heat-damaging produces good splenic localization of 99mTc-RBCs but requires rigidly controlled incubation conditions. NEM-damaging provides an excellent and predictable alternative approach.