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关键词： 流体包裹体   流体演化   成矿过程   岗讲矿床   冈底斯   西藏  

摘要： 岗讲斑岩型铜矿床是西藏冈斯成矿带一个大型铜矿床。成矿作用主要与黑云二长花岗岩、石英二长斑岩和闪长斑岩密切相关。根据包裹体在室温下的相态充填度以及是否含有子矿物等,将岗讲矿床的流体包裹体分为3大类:富液相包裹体(I)、富气相包裹体(II)和含子矿物多相包裹体(III)。其中,黄铜矿–黄铁矿化阶段流体包裹体主要为I、II和III类包裹体,均一温度在173.2℃~493.2℃之间,盐度为1.74%~36.2% NaCleqv;辉钼矿–黄铜矿化阶段的流体包裹体主要为I、II和III类包裹体,均一温度介于179.8℃~390℃之间,盐度为7.13%~35.2% NaCleqv,早晚成矿阶段流体包裹体均一温度略有降低,盐度变化范围基本保持一致,表示流体发生过多次不混溶作用,预示压力的逐渐降低和硫化物的沉淀。成矿流体总体表现为中温、低盐度的NaCl-H2O体系,可能与青藏高原快速隆升过程中大量大气降水参与成矿活动有关。激光拉曼探针分析结果表明,流体包裹体液相成分主要为H2O,气相成分含有CO2,子矿物含少量黄铜矿。但是该矿床品位总体偏低,规模有限,可能是原始岩浆流体“先天不足”造成。

关键词： Shift registers   Nonlinear feedback shift registers   NFSR   Affine functions   Output sequence quality   CASCADE CONNECTION   DECOMPOSITION  

摘要： Nonlinear feedback shift registers (NFSR) are widely used in cryptography as the source of pseudo-random sequences used in ciphers. The nature of the feedback in a given NFSR affects its output sequence and its statistical quality. The complexity of the problem of restoring the initial state of an NFSR by partially known values of the output is one of the signs of a "good" NFSR. In this regard, we note that the presence of the output affine functions lowers the quality of an NFSR since the corresponding problem is reduced to the solution of a system of linear equations. This paper is concerned with the conditions providing the absence of nontrivial affine functions among NFSR output functions. The obtained theoretical results can be used to improve the effectiveness of experimental methods of finding NFSRs with no affine output functions.

关键词： Pulsating intermittent   Liquid-solid fluidized bed   Sinusoidal pulsation liquid velocity   Flow characteristics   Numerical simulation   PARTICLES   SIMULATIONS   BEHAVIOR  

摘要： The sinusoidal pulsation velocity was proposed in this work to further improve the relative velocity and mass transfer efficiency between the liquid and solids phases. The flow behavior of the particles and the relative velocity between the liquid and solids phases were simulated by Eulerian-Eulerian approach incorporating the kinetic theory of granular flow. The numerical results agreed well with the experimental data obtained by the laboratory experimental system. The average axial solids holdup ina whole time period of the sinusoidal liquid velocity was higher in the middle part and lower at the top and bottom of the fluidized bed. The average relative velocity between the liquid and solids phases of the whole bed changed ina sinusoidal form with the same time period of the liquid velocity. Based on the numerical results, the regressional empirical formula of the relative velocity between the liquid and solids phases was obtained. (c) 2021 Published by Elsevier B.V.

关键词： Inherited retinal diseases   Gene therapy   Stem cell therapy   Photoreceptor cells   Fovea   Vessel density   Imaging biomarkers   Visual acuity   Vascular insufficiency   GENE-THERAPY   RETINAL DEGENERATION   VISUAL FUNCTION   BLOOD-FLOW   TRANSPLANTATION   SAFETY   RESTORATION   EPITHELIUM   EFFICACY   MODEL  

摘要： Purpose Choriocapillaris insufficiency may play a role in centripetal retinitis pigmentosa (RP) progression involving the fovea. However, the relationship between choriocapillaris integrity and foveal damage in RP is unclear. We examined the relationship between choriocapillaris flow and the presence of foveal photoreceptor involvement in RP. Methods We categorized the severity of central involvement in RP by the occurrence of foveal ellipsoid zone (EZ) disruption: present (severe RP) or absent (mild RP). Using optical coherence tomography angiography (OCTA, AngioVue, Optovue) in cases and unaffected age-matched controls, we compared vessel density (VD) between the groups using the generalized linear mixed model, controlling for age, gender, and scan quality. Results Fifty-seven eyes (20 severe RP, 18 mild RP, and 19 controls) were included. Foveal and parafoveal mean outer retinal thickness (mu m) were lower in severe RP (fovea: 101.3 +/- 14.5; parafovea: 68.4 +/- 11.7) than controls (fovea: 161.2 +/- 8.9; parafovea: 142.1 +/- 11.8; p <= 0.001) and mild RP (fovea: 162.0 +/- 14.7; parafovea: 116.8 +/- 29.4; p <= 0.0001). Foveal choriocapillaris VD (%) was lower in severe RP (56.7 +/- 6.8) than controls (69.9 +/- 4.6; p = 0.008) and mild RP (65.3 +/- 5.3; p = 0.01). The parafoveal choriocapillaris VD was lower in severe RP than controls (64.4 +/- 5.9 vs. 68.3 +/- 4.1; p = 0.04) but no different than in mild RP (p = 0.4). Conclusion Choriocapillaris flow loss was associated with fovea-involving photoreceptor damage in RP. Further research is warranted to validate this putative association and clarify causation. Choriocapillaris imaging using OCTA may provide information to supplement structural OCT findings when evaluating subjects with RP in neuroprotective or regenerative clinical trials.

关键词： Dynamical low-rank approximation   Conservative numerical methods   Complexity reduction   Vlasov equation   Kinetic equation   PROJECTOR-SPLITTING INTEGRATOR   TIME INTEGRATION   APPROXIMATION   ALGORITHM  

摘要： The primary challenge in solving kinetic equations, such as the Vlasov equation, is the high-dimensional phase space. In this context, dynamical low-rank approximations have emerged as a promising way to reduce the high computational cost imposed by such problems. However, a major disadvantage of this approach is that the physical structure of the underlying problem is not preserved. In this paper, we propose a dynamical low-rank algorithm that conserves mass, momentum, and energy as well as the corresponding continuity equations. We also show how this approach can be combined with a conservative time and space discretization. (C) 2021 The Author(s). Published by Elsevier Inc.

关键词： Cement   Granulation   Coal ash   Fluidized bed reactor   CLINKER FORMATION   SO3   MGO   KILN  

摘要： A new two-process Portland cement clinker manufacturing equipment was utilized to substitute traditional rotary kilns for emission reduction. Cement raw meal became an intermediate product after calcination in the pretreatment process, and the intermediate product turned into a clinker after the final calcination process. During the pretreatment process, the cement raw meal granulated and CaCO3 decomposition and C2S formation occurred simultaneously. Compositions of coal ash differed with cement raw meal and influenced mineral formation and granulation in the first process. Clinker quality and equipment feasibility were influenced accordingly. Therefore, the influence of coal ash component, content and ash fusion temperature on mineral formation and granulation was investigated. Results showed that high-SiO2/Al2O3 coal ash decreased C2AS formation in the intermediate product. Minor component MgO and alkali oxides had no contribution to C2S formation. SO3 promoted C2S formation and suppressed C2AS formation. Mineral types remained unchanged and mass fraction of granules over 1 mm in intermediate products fluctuated slightly as coal ash content increased. Ash fusion temperatures of coal ash were not directly related to granulation. The pretreatment process was feasible and suggestions for fuel selection were provided from the view of coal ash.

关键词： 湘西   沅麻盆地   古隆起   白垩系   寒武系   古流体   二次生烃   页岩气  

摘要： 因古隆起周缘页岩生烃时间晚、热演化程度低,目前已成为中扬子地区油气勘探的重要领域.雪峰古隆起形成于加里东末期,经历了后期复杂的沉积-构造演化,白垩系覆盖区勘探方向尚未明确.以雪峰古隆起西侧沅麻盆地北部为主要研究对象,通过对不整合于寒武系页岩之上的白垩系底部方解石脉与寒武系页岩方解石脉地球化学和包裹体对比分析,研究了古流体形成环境、来源及其对寒武系生烃演化过程的指示.研究结果表明:(1)白垩系脉体碳氧同位素与围岩具有相似性,REE无明显的Eu异常,与寒武系脉体Eu强正异常对比鲜明,表明白垩系脉体主要来自白垩系,受寒武系页岩的影响弱;(2)白垩系方解石脉采样位置位于构造高位,但是包裹体类型显示以纯水溶液包裹体为主,形成于弱还原-弱氧化的环境,未见沥青和明显的纯甲烷包裹体,表明寒武系大规模生排烃在白垩系沉积之前;(3)以包裹体均一温度和Ro为制约,结合区域地质特征恢复了沅麻盆地寒武系两种类型埋藏史,即沅麻盆地北部草堂凹陷早期深埋藏,白垩纪以来不具二次生烃的条件;辰溪凹陷南部早期浅埋藏,白垩系以来Ro可能由1.2%升至2.5%,二次生烃潜力较大,是下一步勘探的有利区.

关键词： 减阻剂   表活剂   毛管阻力   表面张力   长8油藏  

摘要： 在刘峁塬区长8油藏某些欠注区域应用部位,除垢剂反应只能在静止条件下进行,分散剂的筛选和使用,尤为重要。根据长期对表面活性剂研究的结果,并结合油层实际温度、地层水矿化度及组成,本文对常用的表面活性剂进行了界面张力筛选。在表面活性剂C-036/C-912有效浓度在0.05%~0.30%低而宽的范围内,界面张力可以降低到10^(-3)m N/m数量级的超低值,可大幅度降低注入水在毛管中的流动阻力。同时,设计三组对比实验,配制不同浓度的减阻剂,进行岩心驱替实验。随着减阻剂浓度的增加,储层渗透率增加,200ppm的减阻剂效果最好。

关键词： 直立性眩晕   分类   直立性头晕   血流动力学   自主神经功能障碍   直立性低血压   体位性心动过速综合征   Bárány协会  

摘要： 本文《血流动力学相关直立性头晕/眩晕(hemodynamic orthostaticdizziness/vertigo,HOD/V)诊断标准》被纳入国际前庭疾病分类(International ClassificationofVestibularDisorders,ICVD)。定义HOD/V诊断标准的目的是帮助临床医生能够更好地理解直立性头晕/眩晕相关的术语以鉴别直立性头晕/眩晕是由脑低灌注因素还是由其他病因所致。HOD/V诊断标准:(A)至少5次由起身引发或直立体位时出现的头晕、不稳或眩晕,坐下或躺下后缓解;(B)站立或直立倾斜试验时记录到直立性低血压、体位性心动过速综合征或晕厥;(C)不能归因于其他疾病。很可能的HOD/V诊断标准:(A)至少5次由起身引发或直立体位时出现的头晕、不稳或眩晕,坐下或躺下后缓解;(B)至少有一项伴随症状:全身乏力或疲劳感、思维迟缓或注意力难以集中、视物模糊、心动过速或心悸;(C)不能归因于其他疾病。这些诊断标准是基于广泛回顾近九十年来关于HOD/V、体位性低血压或心动过速及自主神经性头晕的相关研究达成的专家共识。进一步测量直立位血压和心率对于筛查和记录直立性低血压、体位性心动过速综合征以确立HOD/V的诊断具有重要意义。

关键词： Dual fluidized bed   CPFD simulation   Electrical capacitance tomography   Flow characteristics   Start-up characteristics   STEAM GASIFICATION   BIOMASS GASIFICATION   WOODY BIOMASS   MODEL   HYDRODYNAMICS   CFD   PARTICLES  

摘要： It is necessary to investigate and understand the gas-solid flow characteristics for the design and optimized operation for chemical looping combustion reactors and other chemical process which involves dual fluidized bed (DFB) system. In this research, computational fluid dynamics simulation was performed in a lab-scale cold three-dimensional full-loop dual fluidized bed model based on the Particel-In-Cell (MP-PIC) method to understand its gas-solid flow characteristics. The simulated results were analyzed and validated with the pressure and electrical capacitance tomography (ECT) measurements. It has been shown that Wen-Yu/Ergun drag model is feasible for the prediction of the gas-solid flow dynamics of this DFB system. The simulated particle volume fraction and ECT results have a good agreement. In the bubbling fluidized bed (BFB), four flow zones are identified based on the bubble and particle behaviors. In each zone, bubbles are mainly concentrated in the middle region. Moreover, the fluidizing air in the chute functions as a secondary air of the BFB to facilitate the particle movement. The BFB and the lower U valve are working as one component and function as a particle buffer region. Therefore, the balance of the whole system is determined by the time when the riser reaches steady state. The higher the air inlet velocity of the riser, the sooner the system reaches steady operation. In addition, the start-up characteristics among the riser, the BFB and U-valve are investigated based on the simulation results. The results indicated that there is a start-up time lag between the riser and bubbling fluidized bed when they each reach steady state.