高分六号宽幅相机在轨几何定标及精度验证

高分六号宽幅相机能够实现单相机成像幅宽优于800 km,对大尺度地表观测和环境监测具有独特优势。在轨几何定标是光学遥感卫星几何处理的关键环节,直接影响影像的几何质量。本文充分考虑高分六号宽幅相机超大视场的畸变特性以及多谱段的成像特点,提出宽幅相机在轨几何定标方法,采用基于探元指向角的几何定标模型补偿宽幅相机系统误差,通过绝对定标和相对定标方法联合估计各波段的内外定标参数。利用Landsat 8影像、资源三号DSM为参考数据,对宽幅相机进行绝对定标处理,再利用ASTER GDEM为参考数据进行相对定标处理,其几何定标结果表明,高分六号宽幅影像绝对定位精度在3像素左右,内部几何精度能稳定在1像素,且波段间配准精度在0.3像素以内,表明在轨几何定标后高分六号宽幅影像几何质量得到了明显的提升。     

低盐度突变对中国对虾仔虾存活率的影响

１９９６年３－４月在山东日照市代家村对虾育苗场采集中国对虾仔虾,采用实验室培养的方法,研究中国对虾仔虾对不同低盐度突变的幅度及速率的适应能力,并对在不同盐度突变后仍能存活的仔虾体内的１８种氨基酸、１４种脂肪酸及５种维生素的含量作了分析比较。结果表明,当降盐的工范围为３／ｄ－５／ｄ时,部分仔虾可在盐度为零的淡水中存活数天。盐度的变化对仔虾体内氨基酸,脂肪酸和维生素的含量均有一定影响。     

顾及字符特征的中文地名词典查询方法

地名词典查询是地名校正、地名匹配等地名服务应用的重要基础,但是地名数量的快速增长使得词典查询性能面临严峻挑战。针对大规模数据环境中传统词典查询方法准确率不高且效率较低等问题,提出了一种顾及字符特征的中文地名词典查询方法（CGQM）。首先,查询具有相同字符特征的地名形成候选地名集合,同时构建单字索引提升查询效率;其次,依据字符数量特征比较查询地名与候选地名的差异,进一步过滤候选地名集合;最后,基于字符位置特征优化查询结果排序策略,使得结果排序更为合理。实验以全国地名词典为例,构建5组测试集进行CGQM方法与Lucene检索方法的对比分析。研究结果表明,CGQM方法对于增强地名词典查询功能、提升查询效率具有实际意义。     

光学微盘腔与三能级量子点系统中的模耦合研究

用一种全量子理论方法研究了波导、光学微盘腔与三能级量子点耦合系统的动力学过程,求出其耦合后的透射模和反射模的解析解. 由于微腔表面粗糙引起反向散射,在微腔内形成两简并回音壁耦合共振模,其耦合率为β;量子点的两激发态分别以耦合率g₁,g₂与回音壁耦合共振模产生耦合. 在实数空间里,得出透射光谱和反射光谱的数值解,这些三能级模型结果比二能级模型结果更接近真实光学微盘腔系统,能更好地显示耦合系统的动力学特性.     

雷诺数对圆形渐缩喷嘴湍流射流的影响

The present study systematically investigates by experiment the influence of Reynolds number (Re) on a turbulent jet issuing from a smoothly-contracting round nozzle. Measurements were performed for seven Reynolds numbers varying from Re = 4,050 to Re = 20,100 using single hot-wire anemometry and over an axial distance of 30 nozzle exit diameters. Although all the exit velocity profiles are of "top-hat" shape, these measurements reveal significant dependence on Re of the exit and downstream flows. The effect of Re on both the mean and turbulent fields is substantial for Re ＜ 10,000 and becomes weak beyond Re = 10,000. The length of the jet’s potential core and the far-field rates of decay and spread all depend significantly on Re.     

Finite element modeling of heating phenomena of cracks excited by high-intensity ultrasonic pulses

A three-dimensional thermo-mechanical coupled finite element model is built up to simulate the phenomena of dynamical contact and frictional heating of crack faces when the plate containing the crack is excited by high-intensity ultrasonic pulses. In the finite element model, the high-power ultrasonic transducer is modeled by using a piezoelectric thermal-analogy method, and the dynamical interaction between both crack faces is modeled using a contact-impact theory. In the simulations, the frictional heating taking place at the crack faces is quantitatively calculated by using finite element thermal-structural coupling analysis, especially, the influences of acoustic chaos to plate vibration and crack heating are calculated and analysed in detail. Meanwhile, the related ultrasonic infrared images are also obtained experimentally, and the theoretical simulation results are in agreement with that of the experiments. The results show that, by using the theoretical method, a good simulation of dynamic interaction and friction heating process of the crack faces under non-chaotic or chaotic sound excitation can be obtained.     

海洋侧孢短芽孢杆菌Lh-1 株所产多肽R-1 性质分析及作用原理探讨

对海洋侧孢短芽孢杆菌(Brevibacillus laterosporus)Lh-1所产多肽R-1的性质及作用机理进行了研究。R-1对温度和pH稳定,在pH 11.0~12条件下,121℃处理1 h,其活力保持在75%以上。经3种不同浓度的蛋白酶(碱性蛋白酶、胰蛋白酶、胃蛋白酶)处理4 h后,活性保持在80%以上。与常见的金属离子和化学试剂在一起反应,对抗菌肽R-1的活性无明显影响,可以配合一起使用,仅吐温和SDS对其影响较大。氨基酸分析表明,抗菌肽R-1由亮氨酸(Leu)、酪氨酸(Tyr)、缬氨酸(Val)、异亮氨酸(Ile)、赖氨酸(Lys)、甘氨酸(Gly)、蛋氨酸(Met)、丝氨酸(Ser)、丙氨酸(Ala)9种氨基酸组成,其中疏水氨基酸居多。抑菌试验表明R-1的抑菌谱广泛,对经培养分离出来的大肠杆菌及白假丝酵母菌的扫描电境超微结构观察表明,R-1的杀菌机制主要是通过含有带正电荷的Lys与带负电荷的磷脂分子结合,然后R-1的疏水端插入到指示菌的疏水区,改变膜的构象,从而导致菌体的死亡。     

产过氧化氢酶菌株CE-1 的筛选与鉴定

经过含H2O2的平板初筛和摇瓶发酵复筛,从保存的水样中筛选到一株过氧化氢酶高产菌株CE-1,其所产过氧化氢酶活性和比活分别为1 356.2 U/mL和3 401 U/mg。菌株CE-1为革兰氏阴性杆状细菌,根据其形态特征、16S rRNA基因序列系统进化树分析和生理生化特性,以及属内不同种间性状差异等因素的综合分析,将菌株CE-1鉴定为气单胞属(Aeromonas)细菌。     

Antiangiogenic activity of low-temperature lysozyme from a marine bacterium <Emphasis Type="Italic">in vivo</Emphasis> and <Emphasis Type="Italic">in vitro</Emphasis>

We extracted marine low-temperature lysozyme (MLTL), a novel lysozyme, from a marine microorganism through fermentation. Our previous study suggested that a low molecular weight (16 kDa) may exert anti-tumor activity through antiangiogenesis. In this study, we extracted a high weight (39 kDa) and investigated its antiangiogenic activity in vivo and in vitro. Using zebrafish embryos as an in vivo study model, we found that treatment with MLTL significantly inhibited the growth of subintestinal vessels (SIVs) in a dose-dependent manner and that 400 μg/ml MLTL was sufficient to block the growth of SIVs. An in vitro study conducted using human umbilical vein endothelial cells (HUVECs) revealed that MLTL suppressed the proliferation, migration and tube formation of HUVECs in a dose-dependent manner. Interestingly, assays by flow cytometry and DNA electrophoresis indicated that MLTL was able to induce apoptosis of HUVECs. Moreover, further study demonstrated that the disruption of intracellular Ca²⁺ homeostasis may play an important role in MLTL induced apoptosis of HUVECs. Taken together, the results of this study demonstrate for the first time that MLTL inhibits angiogenesis through its pleiotropic effects on vascular endothelial cells and induces apoptosis through regulation of cellular Ca²⁺ levels. The results of this study also revealed a possible mechanism underlying the antiangiogenic effect of MLTL and suggested that MLTL may be a promising new antiangiogenic agent for use in cancer therapy.     

地图概括中空间目标几何信息传递模型研究

地图概括是实现多比例尺地图生产和更新的一种重要理论方法。目前,国际国内制图学界对地图概括的研究主要集中在发展地图概括算法方面,在地图概括的质量评价方面的研究还很少。为此,本文以信息论为理论基础,以地图概括中空间目标几何信息的传递问题为研究对象,以相应空间目标几何信息的传递效率来度量地图概括中单个空间目标的概括质量。首先,建立了地图概括的空间信息传递模型,描述不同比例尺地图之间空间信息的传递过程。进而提出了地图概括过程中空间目标(即:线和面目标)几何信息的传递模型,并且对地图概括中空间目标几何信息的传递状况进行了评估,给出了具体的计算和实现方法。最后,通过实验初步验证了地图概括中空间目标几何信息传递模型的可行性。