大口径激波管中降低雷诺数的方法

提供了一种在大口径激波管中降低2区气流雷诺数的方法。采用该方法雷诺数可由通常的10~6～10~7量级降至工10~5量级。实验结果表明采用此方法后2区流场未受明显扰动。给出了驱动压比 P_41与主激波马赫数 M_S1间关系式并由实验加以验证

Assessing ecological risks of heavy metals to marine organisms in the Jiulongjiang Estuary by species sensitivity distribution

采用物种敏感性分布法(SSd)构建常见重金属元素对海洋生物的SSd曲线,结合九龙江口水体5、8、11月份21个站位重金属调查数据,计算了九龙江口7种重金属(AS,Cd,Cr,Cu,Hg,Pb,zn)不同暴露浓度对海洋生物的潜在影响比例(PAf),并分析了在相应站位重金属复合污染生态风险(MSPAf)。结果表明,7种重金属中AS的生态风险最大(即PAf值最高);时间尺度上,5月份总的MSPAf较其他月份稍高;空间尺度上,西溪至海门岛(1~7号站位)污染较严重,其中又以位于西溪和玉枕洲的2号和5号站位的MSPAf为最。In the present work,a species sensitivity distribution( SSD) method was used to assess the ecological risk of common heavy metals to marine organisms.The ecological risk was characterized by potentially affected fraction( PAF) of species in relation to concentration of the toxic materials.According to the investigation data obtained at 21 stations in the Jiulongjiang Estuary in May,August and November,the PAFs of seven heavy metals( As,Cd,Cr,Cu,Hg, Pb,and Zn) to marine organisms were calculated.The results showed that As had the highest PAF among the seven heavy metals at each station of the Jiulongjiang Estuary.Spatially,the multi-substance PAF( msPAF) in May was higher than in other months.Temporally,the msPAF of the Stations 1-7( from the Xixi Stream to the Haimen Isle of the Jiulongjiang Estuary) suffered from heavier pollution.In particular,the pollution status of the Station 2 and Station 5 was the most serious among all the investigated stations.海洋公益性行业科研经费专项(201105015); 国家海洋局青年海洋科学基金项目(2011143); 国家自然科学基金项目(31101902); 福建省自然科学基金项目(2012J05074); 国家海洋局第三海洋研究所基本科研业务费专项(海三科2011006)资

Preliminary study on PAH degradation by bacteria from contami-nated sediments in Xiamen Western Sea, Fujian, China

In order to estimate the biodegradation of three polycyclic aromatic hydrocarbons (PAHs) compounds, bacterial strains were isolated from marine sediments in three heavily contaminated sites (Yuandang Lake, Dongdu Port and Aquacultural zones in Maluan Bay) in Xiamen Western Sea. The results show three bacterial strains, which used pyrene as the sole carbon source, were identified as strains of Aureobacterium sp., Arthrobacter sp., Rhodococcus sp. The PAH-degrading bacteria isolated had a strong ability to degrade phenan-hrene, fluoranthene and pyrene at different degradation rates. The highest degradation rate was observed when three PAH compounds were mixed with an individual strain in the medium. The three PAHs were degraded after one week with a degradation rate of 89.94 % for phenanthrene and 93.4 % for both of fluoranthene and pyrene. In addition, after 25 days of incubation, the degradation rate was 99.98 % for phenanthrene and 99.97 % for both of fluoranthene and pyrene. Optical density was measured to ..

MIM隧道发光二极管的电子输运研究

该文报道了MIM隧道二极管的发光和负阻现象，用梯形势垒计算了电流-电压特性。结果显示，由于SPP波对电子的阻挡和束缚作用引起的势垒平均宽度的增加所导致的负阻现象与实验结果相符合

黄河鲤全同胞家系的微卫星标记亲子鉴定

本研究利用11个高度多态的微卫星标记对26个黄河鲤（Cyprinus carpio haematoperus）全同胞家系中的417尾体重较大的正常体色个体（黄河鲤较大个体）和52尾红色个体（红鲤表型个体）进行了亲子鉴定。11个微卫星座位的平均等位基因数、平均观测杂合度（风）、平均期望杂合度（伉）和平均多态信息含量（PIC）分别为8．2、0．792、0．792和0．76。当双亲未知且置信度为95％时，11个座位的累积排除概率达99．79％。除29尾黄河鲤较大个体以外，388尾黄河鲤较大个体和52尾红鲤表型个体准确地找到了其父母本，实际鉴定率为93．82％。通过对子代数目超过20尾的7个黄河鲤家系生长性状的比较分析，本研究成功鉴定出子代生长性状优良的黄河鲤亲本组合及其家系，同时也鉴定出包含隐性红色基因的黄河鲤杂合亲本，为进一步选育表型和体色纯正且生长快速的黄河鲤新品种提供了理论依据和技术手段

扩张激波管流动波图观察

等截面激波管的计算方法已发展得很完善。为了获得强激波,经常采用“收缩”激波管,它的驱动段截面大于被驱动段,夹膜处加上收缩喷管作过渡。在低密度气体研究或激波强度不高而又要求大的被驱动段的场合,为了节省驱动气体用量,则常选用“扩张”激波管。其驱动段截面小于被驱动段,两者通过扩张喷管相接。对于缝合分界面运行

黄河鲤全同胞家系的微卫星标记亲子鉴定

本研究利用11个高度多态的微卫星标记对26个黄河鲤（Cyprinus carpio haematoperus）全同胞家系中的417尾体重较大的正常体色个体（黄河鲤较大个体）和52尾红色个体（红鲤表型个体）进行了亲子鉴定。11个微卫星座位的平均等位基因数、平均观测杂合度（风）、平均期望杂合度（伉）和平均多态信息含量（PIC）分别为8．2、0．792、0．792和0．76。当双亲未知且置信度为95％时，11个座位的累积排除概率达99．79％。除29尾黄河鲤较大个体以外，388尾黄河鲤较大个体和52尾红鲤表型个体准确地找到了其父母本，实际鉴定率为93．82％。通过对子代数目超过20尾的7个黄河鲤家系生长性状的比较分析，本研究成功鉴定出子代生长性状优良的黄河鲤亲本组合及其家系，同时也鉴定出包含隐性红色基因的黄河鲤杂合亲本，为进一步选育表型和体色纯正且生长快速的黄河鲤新品种提供了理论依据和技术手段

基于VERICUT非圆齿轮磨齿虚拟加工研究

在VERICUT软件环境下建立了虚拟数控非圆齿轮磨齿机床.首先基于成形砂轮展成磨削非圆齿轮的基本原理,进行了磨床的运动数据计算,并构造了符合实际加工要求的G代码形式.然后在 VERICUT下进行了机床模型的搭建,并根据实际磨床的系统特性,选择了合适的控制器,配置了相关参数,建立了非圆齿轮数控加工的虚拟磨床系统.最后在VERICUT下进行了非圆齿轮的加工仿真,对加工仿真中各种干涉情况进行了检查.通过该方法,可以很好地验证非圆齿轮磨削理论的准确性,同时为后续非圆齿轮的实际加工提供了可靠依据