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11.
Using Wang–Landau sampling with suitable Monte Carlo trial moves (pull moves and bond-rebridging moves combined) we have determined the density of states and thermodynamic properties for a short sequence of the HP protein model. For free chains these proteins are known to first undergo a collapse “transition” to a globule state followed by a second “transition” into a native state. When placed in the proximity of an attractive surface, there is a competition between surface adsorption and folding that leads to an intriguing sequence of “transitions”. These transitions depend upon the relative interaction strengths and are largely inaccessible to “standard” Monte Carlo methods. 相似文献
12.
An experimental study was performed to compare the effects of high- and low-pressure exhaust gas recirculation loops (HP and LP EGR loops) on thermal efficiency and emissions of a diesel engine. Tests were conducted on a 12-L six-cylinder turbocharged diesel engine under various operating conditions. We found that at a low speed of 1100 r/min, 1 MPa BMEP, the LP EGR loop could achieve higher brake thermal efficiency and lower emissions than the HP EGR. This is because the lower enthalpy available at the turbine inlet of the HP EGR loop increased the fuel/oxygen equivalence ratio. For the HP EGR, the gross indicated thermal efficiency was reduced by 1%, but pumping losses were only reduced by 0.5%, compared to the LP EGR loop. At a higher speed of 1600 r/min, 1 MPa BMEP, the HP EGR loop attained a higher brake thermal efficiency and lower emissions because of the relatively sufficient flow through the turbocharger. For the HP EGR loop, the gross indicated thermal efficiency was only reduced by 0.5% and pumping losses were reduced by 1.5%, compared to the LP EGR loop. Lower fuel consumption and a longer ignition delay made the distribution of fuel/oxygen equivalence ratio more homogeneous, leading to lower emissions. Our data also showed that at the high speed of 1600 r/min, 0.55 MPa BMEP, the brake thermal efficiency of the HP EGR loop first increased, then decreased as the EGR rate increased. Therefore, under all conditions, a reasonable match of both EGR loops could achieve a good balance between fuel consumption and emissions of NO x and soot. 相似文献
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通过合理的化学成分设计和控制轧制、控制冷却技术的应用,包钢钢联公司薄板坯连铸连轧厂成功地开发和研制出了HP295焊接气瓶用热轧钢带,并对批量试生产产品的性能和金相组织进行了分析。 相似文献
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分析了华能南通电厂350MW机组原高压加热器控制和保护系统存在的缺陷,并提出了具体的改进方案:(1)淘汰气动控制器,以DCS实现其控制;(2)改进高压加热器危急疏水方式;(3)增加变送器数量;(4)改进保护逻辑和保护参数的设定。改进后的系统运行情况良好。 相似文献
18.
耐高温合金材料在服役过程中会发生高温劣化,主要表现为微观组织结构的变化,从而导致在其中传播的超声波能产生显著的高次谐波.针对HP40Nb合金钢材料高温劣化的检测及评价,提出采用归一化超声纵波非线性参量来表征材料的高温损伤状态.对HP40Nb损伤试样进行了非线性超声信号的测量结果显示,归一化超声纵波的非线性参量随着材料高温加载时间呈现出显著的上升-平稳-下降趋势.对材料微观组织演化过程进行了扫描电镜(SEM)的观察和分析,结果表明,超声非线性参量在早期阶段的上升与HP40Nb材料高温加载过程中η相等第二相的析出和聚集密切相关;其在后期阶段的下降归因于析出相的减少和脱落以及微孔洞的产生.由此可见,非线性超声对HP40Nb材料高温劣化后微观组织的变化非常敏感. 相似文献
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Nowadays, hydropneumatic transformer (short for HP transformer) is widely used as the main part of the power system of air‐powered vehicles to pump pressurized hydraulic oil from compressed air with a lower pressure. In this paper, the power system of a new kind of air‐powered vehicle is built using HP transformer as the pneumatic pressure boosting structure and hydraulic motor as the power unit. To set a foundation for the optimization of the power system, the dynamic characteristics are analyzed by building the mathematic model and setting up the experimental station. What is more, the affection of several key structure parameters is researched. Through experimental and simulation study, it can be concluded that, firstly, the mathematical model is proved to be effective; secondly, increasing the area ratio of the pistons would improve the output power as well as reduce the system efficiency, and we choose 6 for a balanced choice; thirdly, the output power and the system efficiency will rise with a larger oil discharge orifice; lastly, the increasing pressure of the input air will raise the power and meanwhile decrease the efficiency. In this system, the efficiency will remain above 30%. This research can be referred to in the design of the power system of air‐powered vehicle and the study on the optimization of the dynamic characteristics. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
20.
Viscosity reduction of isotonic solutions of the photosensitizer TPCS2a by cyclodextrin complexation
Marianne Lilletvedt Tovsen Ingunn Tho Hanne Hjorth Tønnesen 《Drug development and industrial pharmacy》2018,44(2):261-265
Meso-tetraphenyl chlorin disulphonate (TPCS2a) is a photosensitizer (PS) particularly developed and patented for use in the technology of photochemical internalization (PCI) against cancer. TPCS2a is known to aggregate in aqueous media even at low concentrations (≥0.1?µM) and to form a high-viscosity network at clinically relevant concentrations (mM). The aim of this work was to evaluate the effect of two hydroxypropylated cyclodextrin derivatives of beta and gamma type, respectively i.e. HPβCD and HPγCD, on the aggregation and solubilization of TPCS2a in isotonic solutions. Samples containing micromolar concentrations of TPCS2a were studied spectrophotometrically, while samples containing a clinical relevant concentration (10?mM?=?9?mg/ml) of TPCS2a were evaluated by dynamic viscosity measurements. HPβCD was determined to be a more suitable solubilizer of TPCS2a than HPγCD in aqueous media both in the absence and presence of salt. The complexation stoichiometry between TPCS2a/HPβCD at micromolar to millimolar concentrations of TPCS2a was determined to be 1:3 and 1:2 in the absence and presence of isotonic NaCl, respectively. The network of TPCS2a (10?mM) was broken down in the presence of 3% w/v (=?20?mM) HPβCD, i.e. a 1:2 molar ratio between TPCS2a and the cyclodextrin. Formation of the inclusion complex resulted in low viscosity samples both in water and in the presence of isotonic NaCl or phosphate buffered saline (PBS) at 25?°C and 37?°C. 相似文献