Statistical Simulation of Rarefied Gas Flows in Micro-Channels

Rarefied gas flows through micro-channels are simulated using particle approaches, named as the information preservation (IP) method and the direct simulation Monte Carlo (DSMC) method. In simulating the low speed flows in long micro-channels the DSMC method encounters the problem of large sample size demand and the difficulty of regulating boundary conditions at the inlet and outlet. Some important computational issues in the calculation of long micro-channel flows by using the IP method, such as the use the conservative form of the mass conservation equation to guarantee the adjustment of the inlet and outlet boundary conditions and the super-relaxation scheme to accelerate the convergence process, are addressed. Stream-wise pressure distributions and mass fluxes through micro-channels given by the IP method agree well with experimental data measured in long micro-channels by Pong et al. (with a height to length ratio of 1.2:3000), Shih et al. (l.2:4800), Arkilic et al. and Arkilic (l.3:7500), respectively. The famous Knudsen minimum of normalized mass flux is observed in IP and DSMC calculations of a short micro-channel over the entire flow regime from continuum to free molecular, whereas the slip Navier-Stokes solution fails to predict it.

Identification of Prorocentrum minimum and Takayama pulchella by fluorescence in situ hybridization through epifluorescence microscopy and flow cytometry

Partial rDNA sequences of Prorocentrum minimum and Takayama pulchella were amplified, cloned and sequenced. and these sequence data were deposited in the GenBank. Eight oligonucleotide probes (DNA probes) were designed based on the sequence analysis. The probes were employed to detect and identify P. minimum and T. pulchella in unialgal and mixed algal samples with a fluorescence in situ hybridization method using flow cytometry. Epifluorescence micrographs showed that these specific probes labeled with fluorescein isothiocyanate entered the algal cells and bound to target sequences, and the fluorescence signal resulting from whole-cell hybridization varied from probe to probe. These DNA probes and the hybridization protocol we developed were specific and effective for P. minimum and T. pulchella, without any specific binding to other algal species. The hybridization efficiency of different probes specific to P. minimum was in the order: PM18S02 > PM28S02 > PM28S01 > PM18S01, and that of the probes specific to T. pulchella was TP18S02 > TP28S01 > TP28S02 > TP18S01. The different hybridization efficiency of the DNA probes could also be shown in the fluorescent signals between the labeled and unlabeled cells demonstrated using flow cytometry. The DNA probes PM18S02, PM28S02; TP18S02 and TP28S01, and the protocol, were also useful for the detection of algae in natural samples.

Simple method for estimating minimum bend radii of SOI single mode curved rib waveguides

A simple method based on the effective index method was used to estimate the minimum bend radii of curved SOI waveguides. An analytical formula was obtained to estimate the minimum radius of curvature at which the mode becomes cut off due to the side radiative loss.

Three-Dimensional Linear Instability Analysis of Thermocapillary Return Flow on a Porous Plane

A three-dimensional linear instability analysis of thermocapillary convection in a fluid-porous double layer system, imposed by a horizontal temperature gradient, is performed. The basic motion of fluid is the surface-tension-driven return flow, and the movement of fluid in the porous layer is governed by Darcy's law. The slippery effect of velocity at the fluid-porous interface has been taken into account, and the influence of this velocity slippage on the instability characteristic of the system is emphasized. The new behavior of the thermocapillary convection instability has been found and discussed through the figures of the spectrum.

大熊猫“盛林1号”放归监测

大熊猫(Ailuropoda melanoleuca)是我国特有的珍稀濒危物种，国家Ⅰ级重点保护野生动物，被称为“国宝”。目前，大熊猫被局限在我国中西部的岷山、邛崃、大相岭、小相岭、凉山和秦岭6大山系中。对大熊猫的保护和研究，我国政府、保护生物学科研人员、社会各界及国际保护组织都做了大量的工作。根据全国三次大熊猫调查结果显示，大熊猫栖息地片段化现象依然存在，形成多个隔离的大熊猫小种群。尤其在小相岭、大相岭、岷山B和岷山C种群，大熊猫数量较少，且栖息地破碎，面临较大威胁。有的山系大熊猫种群数量些已低于最小可存活大熊猫种群的数量，如果不采取人工措施，这些种群的大熊猫存在灭绝的危险。 将圈养大熊猫放归野外，以补充野外大熊猫种群数量，增加其遗传多样性，复壮和扩大野生大熊猫种群，是大熊猫人工繁育的最终目标。为降低放归的风险性，在放归人工繁育大熊猫前，将救护存活的野生大熊猫先有计划放归野外，并对其进行跟踪监测，对积累大熊猫放归经验，进一步研究大熊猫野外生物学习性，丰富放归地大熊猫种群遗传多样性，为人工繁育大熊猫放归野外夯实基础，具有十分重要的意义。2005年8月8日，国家林业局和四川省人民政府联合将救护野生大熊猫“盛林1号”放归于龙溪－虹口国家级自然保护区内岷山B大熊猫种群栖息地，并进行系统监测研究。成功的积累了一些放归经验和放归大熊猫的生物学资料，为人工繁育大熊猫的放归奠定了一定基础。 2005年8月至2007年6月期间，我们采用GPS无线电项圈、粪便DNA检测和红外线自动触发相机陷阱的方法，对大熊猫“盛林１号”进行了追踪监测，获得了以下成果： 1.通过分析“盛林1号”放归后了活动趋势和采用两种贝叶斯方法，利用目前五大山系的已有微卫星遗传数据，检测“盛林１号”与五大山系的遗传关系的远近，推测其来源于邛崃山系的可能性较大。 2.收集了大量“盛林1号”野外生境选择数据。我们认为“盛林1号”放归后经历了应急期、初步稳定期、长途迁徙期三个阶段（这可能是今后放归大熊猫都必经的三个时期），并与当地大熊猫种群已发生交流。目前“盛林１号”仍在寻找适合的巢域。 3.结合过去监测数据分析，在放归区域大熊猫和羚牛尽管同域分布，但由于食性不同，对微生境选择还是有着很大差异，因此保护管理对策要有针对性。 4.“盛林1号”的放归是成功的。救护大熊猫异地放归工作应继续开展，但要改进放归后的监测技术。要改进现有对人工饲养大熊猫野化培训方法和放归方式，才能真正将人工繁殖个体放归野外。 Giant Panda (Ailuropoda melanoleuca) is an endangered species endemic to China. It was listed as National Protected I Class Species and is crowned as “National treasure” of China. The populations of Giant Panda are limited in 6 mountain system in Center-West of China, i.e. Mingshan, Mt. Qionglai, Mt. Daxiangling，Mt. Xiaoxiangling, Mt. Liangshan and Mt. Qinling. The results of the Third National Survey on Giant Panda showed that the habitats of Giant Panda is still fracted and Giant Panda population is divided into several isolated small populations. Population B from Mt. Daxiangling, Mt. Xiaoxiangling and Mt. Mingshan and Population C from Mt. Mingshan are very small with very fracted habitat and are more endangered. Several populations in those mountain systems are smaller than Minimum Viable Population of Giant Panda. It is very possible that those populations will be extinct without artificial help. The ultimate Goal of Reintroduction caged Giant Panda to wild is to increase wild population size and genetics diversity and rebuild and expand wild Giant Panda population. It is of significant to return rescued wild Giant Panda to wild and monitor their behavior before reintroduction artificial reproduced Giant Panda. It will increase our knowledge on reintroduction of Giant Panda. Aug 8th, 2005, “Shenglin 1”, a rescued wild Giant Panda was returned to Longxi-Hongkou National Nature Reservoir, which is habitat of Giant Panda Population B of Mt. Mingshan. A systematic monitor was carried out on “Shenglin 1”, and the successful return enriched our biological knowledge on Giant Panda reintroduction. It will be very help for future conservation work on reintroduce artificial reproduced Giant Panda. “Shenglin 1” was tracked with GPS collar, DNA in feces and infrared-trigged camera from Aug 2005 to Jun 2007. 1. Locomotion behavior and microsatellites comparison with Giant Panda from the 5 mountain systems indicated that “Shenglin 1” is possibly from Mt. Qionglai. 2. Habitat usage of “Shenglin 1” was studied. It was suggested that there were 3 phases after return, i.e. emergency response, preliminary stable phase and long distance locomotion, which could be a general process for other returned Giant Panda. It was indicated that there was some interaction between “Shenglin 1” and local population. “Shenglin 1” is seeking for suitable home range now. 3. Monitor data also indicated that microhabitat preference of Giant Panda and takin (Budorcas taxicolor) are different because of different diet, though they are sympatric. It was suggested that conservation management for the two species should be plan in particular. 4. The reintroduction of “Shenglin 1” is a successful case. The program of return rescued Giant Panda to other habitats is of value and should be continued. However, more improvement is needed for the monitor technique. More improvement is need for feralization and returning before we return artificial reproduced Giant Panda to wild.

Retrieval of Electron Return Time from High-order Harmonics Generated in a Mixture of He and Ne Gases

In terms of single-atom induced dipole moment by Lewenstein model, we present the macroscopic high-order harmonic generation from mixed He and Ne gases with different mixture ratios by solving three-dimensional Maxwell's equation of harmonic field. And then we show the validity of mixture formulation by Wagner et al. [Phys. Rev. A 76 (2007) 061403(R)] in macroscopic response level. Finally, using least squares fitting we retrieve the electron return time of short trajectory by formulation in Kanai et al. [Phys. Rev. Lett. 98 (2007) 153904] when the gas jet is put after the laser focus.

A broad deglacial delta C-13 minimum event in planktonic foraminiferal records in the Okinawa Trough

The equatorial Pacific upwelling zone has been suspected of playing an important role in the global atmospheric CO2 changes associated with glacial-interglacial cycles. In order to assess the influencing scope of the surface water deglacial delta(13)C minimum in the tropical low-latitude Pacific, the core DGKS9603, collected from the middle Okinawa Trough, was examined for 4513 C records of planktonic foraminifera N. dutertrei and G. ruber. The planktonic foraminiferal delta(13)C records show a clear decreasing event from 20 to 6 cal. kaBP., which is characterized by long duration of about 14 ka and amplitude shift of 0.4 x 10(-3). Its minimum value occurred at 15.7 cal kaBP. The event shows fairly synchrony with the surface water deglacial delta(13)C minimum identified in the tropical Pacific and its marginal seas. Because there is no evidence in planktonic foraminiferal fauna and 45180 records for upwelling and river runoff enhancement, the broad deglacial delta(13)C minimum event in planktonic foraminiferal records revealed in core DGKS9603 might have been the direct influencing result of the deglacial surface water of the tropical Pacific. The identification for the event in the Okinawa Trough provides new evidence that the water evolution in the tropical low-latitude Pacific plays a key role in large regional, even global carbon cycle.

环境因子对有毒赤潮生物微型原甲藻（Prorocentrum minimum）生长增殖的影响

本文研究了温度、盐度、PH、营养盐（N、P）；维生素（B_(12)、B_1）、微量元素（Fe、Mn）、底泥抽提液和赤潮生物骨条藻与微型原甲藻生长的关系。结果表明，微型原甲藻增殖生长的适温范围为20－30 ℃，28 ℃时有最大生长率；最适盐度为10－35‰，25‰盐度生长率最高；PH 7.18-8.72范围内生长良好，影响不明显。N、P营养盐能促进微型原甲藻增殖生长，N盐以硝态氮效果最好，容易被吸收利用；氨盐为唯一N源时效果较差，浓度超过100uM时则有抑制作用；亚硝酸盐作用不明显。微型原甲藻主要是利用无机磷；有机磷作唯一P源时不能有效地被吸收利用，对微型原甲藻生长不利；维生素B_(12)促进微型原甲藻增殖生长效果明显，B_(12)与B_1综合效果更好；底泥抽提液、微量元素Fe、Mn都能有效地促进微型原甲藻增殖生长；研究证实底泥中腐植酸（HFA）虽有促进生长的作用，但效果尚不及抽提液，推测可能还有其他有效成分。研究发现中肋骨条藻有刺激微型原甲藻生长的作用，但其具体作用成分还有待研究。所得这些结果对进一步研究阐明微型原甲藻赤潮成因和机理有重要科学意义。

A comparison of future increased CO2 and temperature effects on sympatric Heterosigma akashiwo and Prorocentrum minimum

Very little is known about how global anthropogenic changes will affect major harmful algal bloom groups. Shifts in the growth and physiology of HAB species like the raphidophyte Heterosigma akashiwo and the dinoflagellate Prorocentrum minimum due to rising CO2 and temperature could alter their relative abundance and environmental impacts in estuaries where both form blooms, such as the Delaware Inland Bays (DIB). We grew semi-continuous cultures of sympatric DIB isolates of these two species under four conditions: (1) 20 degrees C and 375 ppm CO2 (ambient control), (2)20 degrees C and 750 ppm CO2 (high CO2),(3) 24 degrees C and 375 ppm CO2 (high temperature), and (4) 24 degrees C and 750 ppm CO2 (combined). Elevated CO2 alone or in concert with temperature stimulated Heterosigma growth, but had no significant effect on Prorocentrum growth. P-Bmax (the maximum biomass-normalized light-saturated carbon fixation rate) in Heterosigma was increased only by simultaneous CO2 and temperature increases, whereas P-Bmax in Prorocentrum responded significantly to CO2 enrichment, with or without increased temperature. CO2 and temperature affected photosynthetic parameters alpha, Phi(max), E-k, and Delta F/F'(m) in both species. Increased temperature decreased and increased the Chl a content of Heterosigma and M Prorocentrum, respectively. CO2 availability and temperature had pronounced effects on cellular quotas of C and N in Heterosigma, but not in Prorocentrum. Ratios of C:P and N:P increased with elevated carbon dioxide in Heterosigma but not in Prorocentrum. These changes in cellular nutrient quotas and ratios imply that Heterosigma could be more vulnerable to N limitation but less vulnerable to P-limitation than Prorocentrum under future environmental conditions. In general, Heterosigma growth and physiology showed a much greater positive response to elevated CO2 and temperature compared to Prorocentrum, consistent with what is known about their respective carbon acquisition mechanisms. Hence, rising temperature and CO2 either alone or in combination with other limiting factors could significantly alter the relative dominance of these two co-existing HAB species over the next century. (c) 2007 Elsevier B.V. All rights reserved.