Negative Coulomb drag in a one-dimensional wire

We observed negative Coulomb drag for parallel coupled quantum wires, in which electrons flow in the opposite directions between the wires. This only occurred under the conditions of strong correlation in the wires, that is, low density, high magnetic field, and low temperature, and cannot be addressed by a standard theory of momentum transfer. We propose a Coulomb drag model in which formation of a Wigner crystal state in the drag wire and a particle-like state in the drive wire is taken into account.     

Stokes drag on a sphere in a nematic liquid crystal

The Stokes-Einstein relation relates the diffusion coefficient of a spherical Brownian particle in a viscous fluid to its friction coefficient. For a particle suspended in anisotropic liquid, theory predicts that the drag coefficient should also be anisotropic. Using video microscopy coupled with particle tracking routines, the Brownian fluctuations of micrometer-sized particles were analyzed to yield a quantitative measurement of the diffusion coefficients parallel and perpendicular to the nematic director. The experimental values agree quite well with recent numerical calculations that take into account the distortions of the director field in the vicinity of the particles.     

Giant fluctuations of coulomb drag in a bilayer system

The Coulomb drag in a system of two parallel layers is the result of electron-electron interaction between the layers. We have observed reproducible fluctuations of the drag, both as a function of magnetic field and electron concentration, which are a manifestation of quantum interference of electrons in the layers. At low temperatures the fluctuations exceed the average drag, giving rise to random changes of the sign of the drag. The fluctuations are found to be much larger than previously expected, and we propose a model that explains their enhancement by considering fluctuations of local electron properties.     

A photon turnstile dynamically regulated by one atom

Beyond traditional nonlinear optics with large numbers of atoms and photons, qualitatively new phenomena arise in a quantum regime of strong interactions between single atoms and photons. By using a microscopic optical resonator, we achieved such interactions and demonstrated a robust, efficient mechanism for the regulated transport of photons one by one. With critical coupling of the input light, a single atom within the resonator dynamically controls the cavity output conditioned on the photon number at the input, thereby functioning as a photon turnstile. We verified the transformation from a Poissonian to a sub-Poissonian photon stream by photon counting measurements of the input and output fields. The results have applications in quantum information science, including for controlled interactions of single light quanta and for scalable quantum processing on atom chips.     

Olfaction: responses of a decapod crustacean are enhanced by flicking

Periodic movements of the olfactory organs, known as "flicking," temporally enhance the response of the olfactory receptors of the spiny lobster to changes in stimulus concentration. This reflex provides the lobster with a physiological mechanism to compensate for the indiscrete temporal nature of chemical stimuli.     

甬沪宁管道添加减阻剂增输试验

为解决甬沪宁管道多油品、多批次条件下的增输问题,在白沙湾-长兴-石埠桥管段开展了应用减阻剂的现场试验。选择白沙湾站、长兴站作为注入点,试验分全线加剂30mg/L和40mg/L两个阶段进行,通过跟踪添加减阻剂后的油头监测数据,及时调整加剂量和站内输油泵组合,最大限度地提高管输量。两个试验阶段管道平均增输率分别为9.3%和11.6%。试验结果表明:在一定范围内增大减阻剂的用量,能够改善减阻剂的增输效果;根据管输原油种类的变化情况,通过灵活调整加剂量和输油泵组合,可以取得较好的增输效果。     

旋刀式草坪割草机切割刀具的研制

本文研制的铰结式切割刀具,其结构特点是刀头铰结在刀体的两端。其优点是:1.当机具在工作中遇到障碍物时刀头能反向回转,可避免刀具和机具的损坏;2.当刀头严重磨损或损坏后可单独更换;3.可使用较小的热处理设备完成热处理。通过不同材料刀头的性能试验,刀头的耐磨性和韧性,都达到或超过同类日本机型的刀具水平,其中由低碳马氏体材料制成的刀头性能最好。     

单振子激励的面内行波旋转超声电机原理

提出了一个单振子激励的面内行波旋转超声电机原理.该电机具有一个连接一个杆形振子的圆环形定子和两个锥形转子,锥形转子由预压力机构压在定子圆环的内边缘.杆形振子为夹心式结构,两组压电陶瓷固定在其中.一组用于激励杆的纵向振动;另一组用于激励杆的弯曲振动.有限元仿真表明: 在杆的纵向振动和弯曲振动共同作用下,定子环上形成了面内行波.利用这个原理制作的样机具有如下性能:空载转速36 r/min,堵转力矩0.25 N·m,起动时间2.53 ms,关断时间3.48 ms.该型电机的定子利用了一个振子激发定子环面内行波,结构简单、紧凑,可望用于机器人关节和一些姿态调整机构的驱动.     

烤烟漂浮育苗土壤替代基质研究

为减少传统基质中草炭、蛭石、膨胀珍珠岩等不可再生资源的开发,降低烤烟育苗成本,利用耕作层土壤、火土、农家肥、营养液肥料的混合物作为烤烟育苗基质进行了漂浮育苗试验。结果表明,在土壤中加入等比例火土、30%农家肥、2%~2.5%营养液肥料作为烤烟育苗基质,其理化指标接近传统基质,能培育出健壮烟苗,出苗率达84.57%,成苗率达97.53%,烟苗生长和农艺性状与传统基质相比差异较小,每池成本较传统基质节省48元。     

仿生沟槽减阻技术的研究和应用进展

针对当前受到广泛关注的仿生沟槽减阻技术,对沟槽面湍流减阻的微观机理、影响沟槽面减阻效果的主要因素、沟槽减阻技术的工业应用等三个方面的国内外研究进展进行了综述,分析了存在的问题并对沟槽减阻技术的发展前景进行了展望。     

仿生沟槽减阻技术的研究和应用进展

针对当前受到广泛关注的仿生沟槽减阻技术,对沟槽面湍流减阻的微观机理、影响沟槽面减阻效果的主要因素、沟槽减阻技术的工业应用等三个方面的国内外研究进展进行了综述,分析了存在的问题并对沟槽减阻技术的发展前景进行了展望。     

滚筒式生物反应器固态发酵的应用研究

传统方法生产丹贝（大豆发酵食品）都以静态方式进行固态发酵，发酵过程中热质传递受到一定的限制，会产生温度梯度，且气体组分不均匀，从而导致发酵产品质量不稳定。滚筒式生物反应器的应用可以促进热质传递，使物料均匀发酵，且易于实现机械化生产和扩大生产规模。笔者参予设计制造了450L的滚筒式生物反应器，并利用其进行了固态发酵生产丹贝的应用研究。以2株根霉为发酵剂，进行了静态和动态固态发酵的对照试验，并对发酵过程中物料的化学组分和微生物组成进行了检测。结果表明，滚筒式固态发酵产品质量可靠；不同的菌株对搅动有不同的反应，其中微孢子根霉对搅动有适应能力，适用于滚筒固态发酵。     

二次回归正交旋转组合设计优化大肥蘑菇液体培养基

为优化大肥蘑菇液体培养基,通过单因子试验确定大肥蘑菇最佳碳源(葡萄糖)、最佳氮源(蛋白胨)及矿物质的适宜浓度(用量)范围,采用二次回归旋转组合设计研究3个参数对大肥蘑菇菌丝生物量的影响,建立数学模型,以获得适宜的配方组合。结果表明,葡萄糖浓度、蛋白胨浓度对大肥蘑菇菌丝体生物量的影响达极显著水平,矿物质添加剂用量达显著水平。最优培养基参数为葡萄糖浓度33.26 g/L、蛋白胨浓度4.24 g/L、矿物质添加剂1.82 mL/L,在该参数组合下,28℃振荡培养8 d,菌丝干重可达16.44 g/L,且经反复试验验证可行。     

Atmospheric new particle formation enhanced by organic acids

Atmospheric aerosols often contain a substantial fraction of organic matter, but the role of organic compounds in new nanometer-sized particle formation is highly uncertain. Laboratory experiments show that nucleation of sulfuric acid is considerably enhanced in the presence of aromatic acids. Theoretical calculations identify the formation of an unusually stable aromatic acid-sulfuric acid complex, which likely leads to a reduced nucleation barrier. The results imply that the interaction between organic and sulfuric acids promotes efficient formation of organic and sulfate aerosols in the polluted atmosphere because of emissions from burning of fossil fuels, which strongly affect human health and global climate.     

A defined medium for a fastidious Spiroplasma

A defined medium (H-1) was developed for cultivation of the suckling mouse cataract agent, Spiroplasma mirum, a fastidious member of the class Mollicutes that causes cataracts and chronic brain infection in inoculated neonate mice. The H-1 medium was used to show the importance of sphingomyelin as a growth factor for the culture of the spiroplasma in vitro. The growth of Spiroplasma mirum and the pathology it induces in sphingomyelin-rich tissues in vivo may be related to this dependency.     

大鲵虹彩病毒转瓶规模化培养条件研究

研究了利用2.0 L转瓶进行大鲵虹彩病毒规模化培养的最佳工艺条件。结果显示,培养液稀释体积为150m L时,1×106个/m L的初始接种细胞密度可使大鲵虹彩病毒滴度达到最高;培养液稀释体积和接种细胞密度存在一定相关性,在不影响病毒滴度的情况下,可以在细胞密度为5×105个/m L时加入300 m L的培养(维持)液以尽可能多的收获病毒。在1∶20和1∶40的病毒接种剂量下,病毒均可大量增殖,滴度最高为104.35TCID50/0.1 m L;接毒方法简化步骤对病毒在转瓶中的增殖无明显影响。在转瓶中EPC细胞接种病毒的增殖动态曲线显示,接种病毒8 h后,病毒滴度开始上升并进入对数生长期,24 h后病毒增值速度趋缓,72 h病毒滴度达到最大。本研究为大鲵虹彩病毒的规模化培养和细胞培养疫苗的规模化制备技术奠定了基础。     

基于菜粕有机肥筛选番茄青枯病高效生防菌的研究

[目的]菜粕有机肥(简称RC)是生物有机肥生产中常用的营养载体,本研究旨在以RC为营养源筛选可高效抑制番茄青枯病致病菌(Ralstonia solanacearum,青枯菌)的生防菌株材料,以提高生物有机肥防控番茄青枯病的效果.[方法]分别采用营养琼脂(NA)和RC培养基,从番茄根际土中分离和筛选青枯菌拮抗菌株,并于温室条件下测定拮抗菌与RC制成的生物有机肥对番茄青枯病的防治效果.[结果]用NA分离的菌株中NA-5在NA平板上对青枯菌的抑菌圈直径最大(29.0 mm),但在RC平板上抑菌能力微弱;而用RC分离的菌株RC-14在RC平板上对青枯菌的抑菌圈直径较大(24.0mm).施用NA-5和RC-14与RC二次发酵制成的生物有机肥BOF5和BOF14的生防效果显著高于单施拮抗菌,BOF14的生防效率达75.9％,显著高于BOF5.BOF14处理根际青枯菌的数量比BOF5低1个数量级.通过形态和16S rRNA基因序列同源性分析,初步鉴定RC-14菌株为土芽孢杆菌属(Geobacillus sp.).[结论]菌株RC-14可能通过利用RC中营养物质产生大量拮抗物质进而抑制番茄根际青枯菌的生长,降低了青枯病发病率.目前尚无Geobacillus sp.菌用于防治青枯病的报道,说明基于营养载体的筛菌思路可以获得新的生防菌资源.     

Improvement of spergualin production by mutation and medium optimization

In order to screen a high-yield spergualin-production strain and an optimal fermentation medium,large numbers of isolates were selected after ultraviolet(UV)mutation and self-tolerant mutation of Bacillus laterosporus A7.A high-yield strain A-94-7 was obtained and the spergualin productivity was 4.1-fold of the parent strain.The genetic stability of the high-yield strain Bacillus laterosporus A-94-7 was very good.After fermentation medium optimization,Bacillus laterosporus A-94-7 was able to produce 380 mg?L-1.The spergualin productivity in Bacillus laterosporus A7 was increased 4.75-fold by mutation and medium optimization.