共查询到20条相似文献，搜索用时 546 毫秒
1.
2.
本文分析了粘土化作用、沉积作用、成岩作用造成油层伤害的原因；应用岩石学微观分析技术对储集层岩性、物性和含油性的剖析及流动实验原理，研制了油层伤害过程判识、残余油可采性分析、油水界面识别等3项油层保护机理分析方法；指出了油层保护机理分析技术在油气层改造、钻前油层保护、高含水油层驱采和油水界面确定等方面的用途。 相似文献
3.
4.
5.
关于微生物细胞数量的镜检计数法的改进 总被引：1，自引：0，他引：1
测定微生物数量的方法很多,在教学实验中比较常用 的一个方法是微生物细胞数量的镜检计数法,即用血球计 数板在显微镜下做微生物的直接计数,所以得的是死菌与 活菌的总和,故称作总菌计数法。由于实验选用的材料是 啤酒酵母或经灭活的大肠杆菌、枯草杆菌等,须提前培 养。费时费力,对环境要求严格,尤其是总菌计数,结 果往往偏高,不利于实验应用。针对这种情况,在实验 教学中,经过多次实践和观察,做了两点改进,一是选 取新的实验材料,用安琪酵母代替原来的实验材料;二是 用吕氏美蓝染液对菌悬液进行染色,再把染色的菌悬液置 入血球计数板镜检计数。现详细介绍如下。 相似文献
6.
应用高精度微量泵和高精度差压传感器实验测定了不同渗透率级别的砂岩样品在不同含水饱和度下的油水两相最小启动压力梯度。对比单相启动压力梯度,发现试验状态下,油水两相最小启动压力梯度与空气渗透率呈幂函数变化关系;油水两相最小启动压力梯度比单相启动压力梯度高数倍。针对储层渗透率、流体粘度、驱替压力梯度、油水界面张力等影响启动压力梯度的具体因素分析了改善低渗透油藏开发效果的措施。 相似文献
7.
8.
9.
《科技风》2021,(3)
古生菌作为一种特殊的微生物类群,在人类皮肤微生物组中是一个恒定但高度可变的组成部分,目前研究发现:奇古菌可能通过硝化作用降低皮肤p H,造成皮肤屏障功能破坏;在土壤、海洋中的氨氧化古菌通过氨氧化作用调节生活环境中的氨氮平衡,与我们生产生活密切相关。因此,越来越多的科研人员对其进行深入探索,但传统实训实验中存在着古生菌分离培养成功率低、周期较长、菌株鉴定成本高、遗传和生化操作技术平台要求高等问题,基于传统实验操作的连贯性、真实性、记忆性等特点,为模拟古生菌实验的细节以减少错误率而拟创建集科普、教学、科研于一体的皮肤古生菌虚拟实验科普互动学习平台——《异"菌"突起》。通过古生菌的发现历程、简介、应用前景等版块提供对极端微生物生活环境和生物学特性与功能角色的介绍,利于虚拟培养板块利用网页交互操作进行线上古生菌相关实验操作模拟(本文主要以氨氧化古菌为代表菌株,模拟其分离、培养与鉴定过程)。 相似文献
10.
长残留磺酰脲类除草剂在我国被广泛应用,其残留会破坏土壤微生物生态系统,影响土壤质量及后茬作物.中国科学院沈阳应用生态研究所针对氯嘧磺隆等磺酰脲类除草剂性质特点,筛选出具有高效降解功能的微生物菌株,通过室内模拟实验证实其对土壤微生物菌群恢复有明显效果.在复合降解菌系田间样地实验中,需要频繁监测并绘制除草剂降解曲线,然而当前传统检测仪器不能满足课题对氯嘧磺隆快速降解的检测需求. 相似文献
11.
Sunghoon Cho Young Jin Choi Shaohui Zheng Jiwon Han Seong Young Ko Jong-Oh Park Sukho Park 《Biomicrofluidics》2015,9(5)
The bacteria-based microrobot (Bacteriobot) is one of the most effective vehicles for drug delivery systems. The bacteriobot consists of a microbead containing therapeutic drugs and bacteria as a sensor and an actuator that can target and guide the bacteriobot to its destination. Many researchers are developing bacteria-based microrobots and establishing the model. In spite of these efforts, a motility model for bacteriobots steered by chemotaxis remains elusive. Because bacterial movement is random and should be described using a stochastic model, bacterial response to the chemo-attractant is difficult to anticipate. In this research, we used a population-scale approach to overcome the main obstacle to the stochastic motion of single bacterium. Also known as Keller-Segel''s equation in chemotaxis research, the population-scale approach is not new. It is a well-designed model derived from transport theory and adaptable to any chemotaxis experiment. In addition, we have considered the self-propelled Brownian motion of the bacteriobot in order to represent its stochastic properties. From this perspective, we have proposed a new numerical modelling method combining chemotaxis and Brownian motion to create a bacteriobot model steered by chemotaxis. To obtain modeling parameters, we executed motility analyses of microbeads and bacteriobots without chemotactic steering as well as chemotactic steering analysis of the bacteriobots. The resulting proposed model shows sound agreement with experimental data with a confidence level <0.01. 相似文献
12.
Jairus Kleinert Vijay Srinivasan Arnaud Rival Cyril Delattre Orlin D. Velev Vamsee K. Pamula 《Biomicrofluidics》2015,9(3)
The operation of digital microfluidic devices with water droplets manipulated by electrowetting is critically dependent on the static and dynamic stability and lubrication properties of the oil films that separate the droplets from the solid surfaces. The factors determining the stability of the films and preventing surface fouling in such systems are not yet thoroughly understood and were experimentally investigated in this study. The experiments were performed using a standard digital microfluidic cartridge in which water droplets enclosed in a thin, oil-filled gap were transported over an array of electrodes. Stable, continuous oil films separated the droplets from the surfaces when the droplets were stationary. During droplet transport, capillary waves formed in the films on the electrode surfaces as the oil menisci receded. The waves evolved into dome-shaped oil lenses. Droplet deformation and oil displacement caused the films at the surface opposite the electrode array to transform into dimples of oil trapped over the centers of the droplets. Lower actuation voltages were associated with slower film thinning and formation of fewer, but larger, oil lenses. Lower ac frequencies induced oscillations in the droplets that caused the films to rupture. Films were also destabilized by addition of surfactants to the oil or droplet phases. Such a comprehensive understanding of the oil film behavior will enable more robust electrowetting-actuated lab-on-a-chip devices through prevention of loss of species from droplets and contamination of surfaces at points where films may break. 相似文献
13.
This paper reports a technique for temperature-induced merging of droplets in a microchannel. The multiphase system consists of water droplet and oil as the dispersed phase and the carrying continuous phase. A resistive heater provides heating in a rectangular merging chamber. The temperature of the chamber is controlled by the voltage applied to the heater. The merging process of two neighboring droplets was investigated with different applied voltage, flow rate ratio between water and oil and total flowrate. Merging is found to be effective at high flow rate ratio, high temperature, and low total flowrate. The presented technique could be used for merging and mixing in droplet-based lab-on-a-chip platforms. 相似文献
14.
稠油油藏水驱采收率低,因其原油黏度高,不适合转化学驱,但转热采可大幅提高采收率。林樊家油田林东馆三段地质条件复杂,地层敏感性强,供液差,产能低,油稠,出砂严重,多年来采用了各种工艺措施,均未取得好的水驱开采效果。在分析低效水驱原因的基础上,论证了水驱转蒸汽热采可行性。开发实践表明,低效水驱稠油油藏通过转热采可大幅提高采收率,同时研究成果对同类油藏的开发具有重要指导意义。 相似文献
15.
我国陆上油田大多已经进入高、特高含水期,开采难度越来越大,选择适合油藏特征的提高采收率技术对于油田稳产增产日趋重要。本研究梳理了我国油田已应用和将要采用的提高采收率技术清单,提出油田中后期提高采收率技术成熟度评估方法,将技术成熟度等级和技术生命周期对应起来,绘制了技术成熟度曲线,并讨论了各类提高采收率技术的未来发展路线。研究结果表明,蒸汽吞吐、蒸汽驱、聚合物驱等技术目前已基本成熟,在适宜油藏类型和地质特征的油田得到了较为广泛地推广应用；稠油开采技术需拓展矿场实验规模和类型；水驱技术需加强对地质油藏的认识程度和表征精度；化学驱技术需进攻关经济、环保、稳定的体系配方；注气技术需突破气源低成本供应瓶颈；微生物驱技术需扩大试验规模,增强实验效果；超前储备颠覆性技术需做大量基础研究、先导试验、技术攻关试验和矿场试验。 相似文献
16.
The cell''s micro-environment plays an important role in various physiological and pathological phenomena. To better investigate in vivo cellular behaviors, researchers have expended great effort in building controlled in vitro biophysical and biochemical environments. Because a cell''s gaseous environment affects properties such as its division, metastasis, and differentiation, we developed a zero-flow based platform for studying mammalian cell chemotaxis behavior in different oxygen environments. This platform can construct a linear range of oxygen tensions within one chip (i.e., from 1.4% to 3.6% or 5.5% to 14.5%). To study cell chemotaxis behavior under varying oxygen environments, the chemical gradient direction is established perpendicularly to oxygen change within an observation area. Because the observation area is not subject to flow, shear force is of no concern. In addition, water flow around the cell chambers greatly reduces evaporation and makes long-term microscope imaging possible. In this study, we precisely measure the chemotaxis velocity of MCF-7 human breast cancer cells under different oxygen tension conditions towards CXCL12, which is a stromal cell-derived factor. We find that cell migration rates are not equivalent, even under two close oxygen tensions. We also observed that cells move faster towards high concentrations of chemoattractant when the oxygen tension is below 3% due to the increased expression of HIF-1 (hypoxia-inducible factor 1), which promotes a transition to the amoeboid rather than mesenchymal mode of movement. Our experiments demonstrate that this new microfluidic platform is useful for the quantitative study of mammalian cell chemotaxis under different oxygen conditions in the absence of shear force. We also shed light on the study of chemotaxis under other gaseous environments. 相似文献
17.
Electrowetting on dielectrics has been widely used to manipulate and control microliter or nanoliter liquids in micro-total-analysis systems and laboratory on a chip. We carried out experiments on electrowetting on a lotus leaf, which is quite different from the equipotential plate used in conventional electrowetting. This has not been reported in the past. The lotus leaf is superhydrophobic and a weak conductor, so the droplet can be easily actuated on it through electrical potential gradient. The capillary motion of the droplet was recorded by a high-speed camera. The droplet moved toward the counterelectrode to fulfill the actuation. The actuation speed could be of the order of 10 mm∕s. The actuation time is of the order of 10 ms. 相似文献
18.
Fangzhi Mou Qi Xie Jianfeng Liu Shengping Che Lamya Bahmane Ming You Jianguo Guan 《国家科学评论(英文版)》2021,8(11)
Synthetic chemotactic micro/nanomotors are envisioned to actively ‘seek out’ targets by following specific chemicals, but they are mainly powered by bioincompatible fuels and only show pseudochemotaxis (or advanced chemokinesis) due to their weak self-reorientation capabilities. Here we demonstrate that synthetic ZnO-based Janus micromotors can be powered by the alternative biocompatible fuel of CO2, and further provide the first example of self-reorientation-induced biomimetic chemotaxis using them. The ZnO-based micromotors are highly sensitive to dissolved CO2 in water, which enables the corrosion of ZnO to continuously occur by providing H+ through hydration. Thus, they can autonomously move even in water exposed to air based on self-diffusiophoresis. Furthermore, they can sense the local CO2 gradient and perform positive chemotaxis by self-reorientations under the phoretic torque. Our discovery opens a gate to developing intelligent micro/nanomotors powered by, and sensitive to, biocompatible atmospheric or endogenous gaseous chemicals for biomedical and environmental applications. 相似文献
19.
20.
The effects of gradients of bioactive molecules on the cell microenvironment are crucial in several biological processes, such as chemotaxis, angiogenesis, and tumor progression. The elucidation of the basic mechanisms regulating cell responses to gradients requires a tight control of the spatio-temporal features of such gradients. Microfluidics integrating 3D gels are useful tools to fulfill this requirement. However, even tiny flaws in the design or in the fabrication process may severely impair microenvironmental control, thus leading to inconsistent results. Here, we report a sequence of actions aimed at the design and fabrication of a reliable and robust microfluidic device integrated with collagen gel for cell culturing in 3D, subjected to a predetermined gradient of biomolecular signals. In particular, we developed a simple and effective solution to the frequently occurring technical problems of gas bubble formation and 3D matrix collapsing or detaching from the walls. The device here proposed, in Polydimethylsiloxane, was designed to improve the stability of the cell-laden hydrogel, where bubble deprived conditioning media flow laterally to the gel. We report the correct procedure to fill the device with the cell populated gel avoiding the entrapment of gas bubbles, yet maintaining cell viability. Numerical simulations and experiments with fluorescent probes demonstrated the establishment and stability of a concentration gradient across the gel. Finally, chemotaxis experiments of human Mesenchymal Stem Cells under the effects of Bone Morphogenetic Protein-2 gradients were performed in order to demonstrate the efficacy of the system in controlling cell microenvironment. The proposed procedure is sufficiently versatile and simple to be used also for different device geometries or experimental setups. 相似文献