First-principles investigation of the concentration effect on equilibrium fractionation of Ca isotopes in forsterite

Previous theoretical studies have found that the concentration variations within a certain range have a prominent effect on inter-mineral equilibrium isotope fractionation(10^3 lna).Based on the density functional theory,we investigated how the average Ca–O bond length and the reduced partition function ratios(10^3 lnb)and103lna of 44 Ca/40 Ca in forsterite(Fo)are affected by its Ca concentration.Our results show that Ca–O bond length in forsterite ranges from 2.327 to 2.267 A with the Ca/(Ca+Mg)varying between a narrow range limited by an upper limit of 1/8 and a lower limit of 1/64.However,outside this narrow range,i.e.,Ca/(Ca+Mg)is lower than1/64 or higher than 1/8,Ca–O bond length becomes insensitive to Ca concentration and maintains to be a constant.Because the 10^3 lnb is negatively correlated with Ca–O bond length,the 10^3lnb significantly increases with decreasing Ca/(Ca+Mg)when 1/64<Ca/(Ca+Mg)<2/16.As a consequence,the 10^3lna between forsterite and other minerals also strongly depend on the Ca content in forsterite.Combining previous studies with our results,the heavier Ca isotopes enrichment sequence in minerals is:forsterite[orthopyroxene[clinopyroxene[calcite & diopside[dolomite[aragonite.Olivineand pyroxenes are enriched in heavier Ca isotope compared to carbonates.The 10^3lna between forsterite with a Ca/(Ca+Mg)of 1/64 and clinopyroxene(Ca/Mg=1/1,i.e.,diopside)is up to^0.64%at 1200 K.The large 103lnaFodiopsiderelative to the current analytical precision for Ca isotope measurements suggests that the dependence of10^3 lnaFo-diopsideon temperature can be used as a thermometer,similar to the one based on the 103lna of 44 Ca/40 Ca between orthopyroxene and diopside.These two Ca isotope thermometers both have a precision approximate to that of elemental thermometers and provide independent constraints on temperature.

Salt effect on the liquid–liquid equilibrium of the ternary (water + phenol + methyl isobutyl ketone) system: Experimental data and correlation

The effects of NaCl, KCl and Na_2SO_4 on the liquid–liquid equilibrium(LLE) data for the ternary system, water+ phenol + methyl isobutyl ketone, were determined at 0.101 MPa and 333.15 K and 343.15 K.The nonrandom two-liquid(NRTL) model was used to correlate the experimental data and to yield corresponding binary interaction parameters for these salt containing systems.The Hand and Othmer–Tobias equations were used to confirm the dependability of the determined LLE data in this work.Distribution coefficient and selectivity were used to evaluate the extraction performance of methyl isobutyl ketone with the existence of salt.The magnitude of salt effect on the water + phenol + methyl isobutyl ketone(MIBK) system is in the following order: Na_2SO_4>NaCl>KCl.

Fiscal Policy Effect Analysis Based on Agents Response Equilibrium (ARE) Model

Agents response equilibrium (ARE) model has been taken advantage of to build a multi-agent system for analyzing fiscal policy effect. Through establishing various types of economic entities and endowing them with abilities to react and make decision, the whole system will evolve to new conditions in response to policy change. Compared with different scenarios, it can be concluded that when raising taxation ratio, sectoral scale will shrink to some extent. But supported by government expenditure, certain sectors could be kept in comparatively larger production scale.

Correlation and Prediction of Salt Effect on Vapor Liquid Equilibrium for the System of 2-Propanol/Water

Binary vapor liquid equilibrium (VLE) data were measured for the systems of 2-propanol/ ethanediol and ethanediol/potassium acetate (KAc). VLE data for the system of propanol/ethanediol was tested using thermodynamic consistency test. The average values of Δy1 and Δ P were 0.0776 and 0.1542 kPa, respectively. The above two sets of VLE data were correlated with the NRTL model. Ternary VLE data for the system of 2-propanol/water/KAc was used to obtain the more suitable parameters of NRTL model for binary systems of 2-propanol/KAc and water/KAc (called TDCM). For multicomponent systems, ternary and quaternary, the VLE values predicted by the NRTL model agreed well with the litera-ture data. Influence of KAc, ethanediol, and the mixture of KAc and ethanediol on volatility between 2-propanol and water was investigated respectively. The results showed that the above-mentioned materials and mixture had different influence on volatility between 2-propanol and water. The method for correla-tion and prediction of salt-containing VLE is simple and effective for the said system.

Nonlinear coupling modeling and dynamics analysis of rotating flexible beams with stretching deformation effect

Dynamic coupling modeling and analysis of rotating beams based on the nonlinear Green-Lagrangian strain are introduced in this work.With the reservation of the axial nonlinear strain,there are more coupling terms for axial and transverse deformations.The discretized dynamic governing equations are obtained by using the finite element method and Lagrange’s equations of the second kind.Time responses are conducted to compare the proposed model with other previous models.The stretching deformation due to rotating motion is observed and calculated by special formulations under dynamic equilibrium.The stretching deformation and the change of the associated equilibrium position are taken into account to analyze the free vibration and frequency response of the rotating beams.Analytical and numerical comparisons show that the proposed model can provide reliable results,while the previous models may lead to imprecise results,especially in high-speed conditions.

Salt Effect on the Liquid-Liquid Equilibrium of （Water ＋ Propionic Acid ＋ Cyclohexanol） System at T=（298.2,303.2,and 308.2） K

Effects of salt and temperature on the liquid phase equilibrium of the(water + propionic acid + cyclohexanol) system were investigated.The liquid-liquid equilibrium data in the presence of KCl for various salt ionic strength of 0.5,1.0,1.5,2.0,and 2.5 mol·dm3 and in absence of the salt at T=(298.2,303.2,and 308.2)K were determined.The experimental results were correlated based on the Othmer-Tobias equation and Pitzer ion-interaction model.Thermodynamic properties such as distribution coefficients and activity coefficients of propionic acid in water + cyclohexanol were determined.In addition,the separation factor,S,of the chosen solvent was obtained for the investigated system.

Catalytic Effect of Activated Carbon and Activated Carbon Fiber in Non-Equilibrium Plasma-Based Water Treatment

Catalysis and regeneration efficiency of granular activated carbon （GAC） and activated carbon fiber （ACF） were investigated in a non-equilibrium plasma water treatment reactor with a combination of pulsed streamer discharge and GAC or ACF. The experimental results show that the degradation efficiency of methyl orange （MO） by the combined treatment can increase 22% （for GAC） and 24% （for ACF） respectively compared to pulsed discharge treatment alone, indicating that the combined treatment has a synergetic effect. The MO degradation efficiency by the combined treatment with pulsed discharge and saturated GAC or ACF can increase 12% and 17% respectively compared to pulsed discharge treatment alone. Both GAC and ACF show catalysis and the catalysis of ACF is prominent. Meanwhile, the regeneration of GAC and ACF are realized in this process. When H202 is introduced into the system, the utilization efficiency of ozone and ultraviolet light is improved and the regeneration efficiency of GAC and ACF is also increased.

Salt-Containing Extractive Distillation of 1-Propanol/Water System 1.Prediction of Salt Effect on Vapor Liquid Equilibrium

This paper has studied the vapor-liquid equilibrium (VLE) for the salt-containing extractive distillation of the 1-propanol/water system. Binary VLE data were measured for the systems of 1-propanol (1)/KAc (4), ethanediol (3)/KAc (4), and 1-propanol (1)/ethanediol (3), with the VLE data correlated with the NRTL model in order to obtain the model parameters of these binary systems. The binary VLE data cited in technical literature were correlated to obtain the model parameters for other binary systems. VLE data of ternary and quaternary systems predicted by the NRTL model agreed well with the literature data. The influence of KAc, ethanediol, and the KAc/ethanediol mixture on volatility between 1-propanol and water was investigated respectively. Test results showed that the above-mentioned materials (KAc, ethanediol) and their mixture (KAc and ethanediol) have different influence on the volatility. When x3=0.5, and x4=0.05, the azeotropic point can be eliminated. The NRTL model method of salt-containing VLE is simple and effective for the prediction of the system's VLE data.

Stability analysis of magnetization in a perpendicular magnetic layer driven by spin Hall effect

We investigate the stability of magnetization in free layer where the spin torque is induced by the spin Hall effect.In terms of the Landau–Liftshitz–Gilbert equation,we find the low-energy and high-energy equilibrium states,as well as the saddle points.The stability region is defined in the phase diagram spanned by the current density and the spin Hall angle.The spin Hall effect makes the previous saddle point into a stable state above a critical current.However,in the presence of magnetic field,the spin Hall effect leads to the opposite changes in the stable regions of the two low-energy states.

On transition of type V interaction in double-wedge flow with non-equilibrium effects

The transition between regular reflection （RR） and Mach reflection （MR） of type V shock-shock interaction on a double-wedge geometry with high temperature non-equilibrium effects is investigated by extended shock-polar method and numerical simulation. First, the critical angles of transition from detachment criterion and yon Neumann criterion are determined by the extended shock-polar method considering the non-equilibrium effects. Then wave patterns and the transition process are numerically obtained. Results of the critical transition angles from shock-polar calculation and numerical simulation show evident disagreement, indicating transition mechanism between RR and MR of type V interaction is changed. By comparing with the frozen counterpart, it is also found that non-equilibrium effects lead to a larger critical wedge angle and a larger hysteresis interval.

Dynamic Analysis of an Algae-Fish Harvested Model with Allee Effect

In this paper, an algae-fish harvested model with Allee effect was established to further explore the dynamic evolution mechanism under the influence of key factors. Mathematical theoretical work not only investigated the existence and stability of all possible equilibrium points, but also probed into the occurrence of transcritical and Hopf bifurcation. The numerical simulation works verified the effectiveness of the theoretical derivation results and displayed rich bifurcation dynamical behaviors, which showed that Allee effect and harvest have played a vital role in the dynamic relationship between algae and fish. In summary, it was expected that these research results would be beneficial for promoting the study of bifurcation dynamics in aquatic ecosystems.

以有效需求牵引供给以高水平供给创造需求——学习习近平宏观经济治理供求关系良性互动的论述

学习和领会习近平宏观经济治理思想尤其是关于供求关系良性互动的论述,有助于梳理我国宏观经济治理与宏观调控政策的发展脉络,进一步深化认识和自觉遵循新时代客观经济规律,对于加快构建新发展格局和实现高质量发展具有非常重要的理论与实践意义。面对经济发展有效需求不足等失衡特点,“深化供给侧结构性改革和扩大有效需求协同发力”已成为新时代做好经济工作需要认识和遵循的重要规律。当前实现需求与供给两端协同发力,在政策目标和政策导向上必须追求以有效需求牵引供给、以高水平供给创造需求,还要从政策制定和传导机制、治理机制和体制基础等方面持续发力以切实提升宏观经济治理和政策调控的有效性。

中国高新技术产品进口关税减让的经济效应

降低高新技术产品进口关税是中国践行扩大开放承诺的有力措施,对于以高新技术产业发展推动高水平科技自立自强具有重要意义。运用可计算局部均衡模型,从产业层面考察了中国高新技术产品进口关税减让的经济影响。研究发现:中国高新技术产品进口关税税率下调对进口的促进效应大于出口,其效应随降税幅度的提高而递增,且现有关税税率越高,降税的贸易效应越大;中国高新技术产品的内销额和消费者价格将减少,但生产者价格和产量变化不大;中国高新技术产业的消费者剩余大幅提高,生产者剩余变化幅度有限,但政府进口关税收入下降明显,所以高新技术产品的社会净福利将减少,其中广播、电视和通讯设备类产品的净福利损失最大,办公、会计和计算机器类产品与航空航天产品的净福利损失较小。研究结果可为中国高新技术产品关税政策调整提供依据,也能为中国主动扩大进口政策制定提供参考。

基于物种敏感度分布及相平衡理论的汾河流域磺胺类抗生素生态风险阈值研究

磺胺素类抗生素(SAs)广泛应用于医疗、畜禽养殖等领域。但过量的SAs通过多种方式最终进入流域水体和沉积物中,对流域生态系统带来潜在的风险。预测无效应浓度(PNEC)可以作为评估污染物潜在生态风险的阈值,因此确定水体和沉积物中SAs的PNEC是风险评估的关键。本研究以黄河支流——汾河流域为研究区,通过采集水体和沉积物的样品,发现水体中SAs的磺胺甲恶唑(SMX)含量最高,均值为73.6 ng·L^(-1),而磺胺醋酰(SAAM)检出率最高,高达100%。沉积物中仅检出了2种SAs类抗生素,为磺胺醋酰(SAAM)和磺胺喹恶啉(SQX),但检出频率却高达100%。基于物种敏感度分布(SSD)得到水体中SAs的生态风险阈值为3.40~440μg·L^(-1)。在此基础上,基于水-沉积物密度、体积比等参数,采用相平衡理论(EqP)进一步得到了沉积物中SAs的生态风险阈值为0.065~75.5 mg·kg^(-1)。基于确定的生态风险阈值,对汾河流域SAs现状进行风险评估,结果表明仅水体中的甲氧苄啶(TMP)的风险商(RQ)均值为0.014,存在一定的低风险,但超标概率仅为8%,而其他类别在水体和沉积物中RQ均低于0.01,均无显著风险。

考虑拱效应的复合地层盾构隧道开挖失稳分析

根据盾构隧道开挖面的特点,考虑不同地层、不同隧道埋深条件下土体成拱效应,基于Paik圆弧拱理论建立失稳土体三维极限平衡理论分析模型。将经典三维楔形体模型改进为垂直面水平面均考虑拱效应的失稳土体三维模型,模拟盾构隧道开挖时前方土体的影响范围和影响大小,将上覆土压力计算方法扩展为三维形式,并采用土体条分法给出失稳土体极限平衡公式。最后利用MATLAB编程将模型计算结果与离心试验及其他理论模型进行了对比验证。结果表明:本文力学模型结果与离心试验结论更接近,可更准确地应用于开挖面最小支护压力参数的确定。

梁板融合预制装配式双拼槽钢-混组合楼板试验

为充分发挥装配式工业化程度高和钢-混组合结构优良力学性能的优势,提出一种装配式双拼槽钢-混凝土组合楼板,对3组简支组合楼板试件进行了四点加载试验,研究了该组合楼板的竖向静载下力学性能。分析了楼板裂缝、挠度、应变(钢筋、钢梁、混凝土板)随荷载发展规律;基于极限平衡法,提出了考虑受拉薄膜效应和刚度强化系数的承载力计算公式。结果表明:组合楼板的变形呈双向板特征,试件破坏时均出现板顶角部裂缝和弧形裂缝,混凝土板底中心区域为网状裂缝和向角部延伸的斜裂缝,双拼主梁发生塑性弯曲;在楼板的中心挠度达到l 0/40时,试件荷载分别为327.63 kN、436.92 kN和406.12 kN,组合楼板承载力较高;钢筋的应变发展在垂直钢梁方向较大,沿着塑性铰线屈服;考虑受拉薄膜效应和刚度强化系数的计算公式与试验结果吻合良好,准确地预测了楼板荷载-挠度全过程曲线。

具有相互干扰和恐惧效应的捕食模型的稳定性

研究一类具有相互干扰和恐惧效应的Lotka-Volterra食饵-捕食模型,分析解的有界性和系统平衡点的存在性,并给出系统持续性的充分条件,通过Dulac判别法得出正平衡点是全局渐近稳定的,具有相互干扰和恐惧效应的食饵-捕食模型能长期共存并保持生态平衡。

浊积岩油藏优势渗流通道精准识别——以胜利油区牛庄洼陷牛20区块为例

针对浊积砂岩油藏牛庄洼陷牛20区块平面水驱不均衡、边部供液不足与核部油井暴性水淹共存的开发状况,围绕浊积岩地质油藏特征,微观上通过三维数字岩心模拟,刻画不同微相微观孔喉结构约束下的优势渗流特征;宏观上基于浊积岩剩余油精细刻画,分级识别优势渗流流线。研究表明,动静态深入结合分析,明确了牛20区块优势渗流通道主要分布在核部微相,采用多技术手段联合识别优势渗流通道,结果与开发动态符合率达85%以上,可精准有效识别各层段的优势渗流通道,提高后续措施挖潜的针对性。研究成果为浊积岩油藏高含水期实现均衡驱替提高采收率奠定基础,对于低渗油藏高含水期效益开发具有重要意义。

基于动静平衡理念髌骨骨折术后康复量化方案临床观察

目的基于“动静平衡”理念的髌骨骨折术后不同康复量对患者膝关节活动度及相关功能的影响。方法选取山东省中医院骨科收治的90例髌骨骨折手术治疗后患者,按照随机数字表法将患者分为观察组A组、观察组B组和对照组C组,每组30例,观察组分别以不同的康复量进行功能锻炼,对照组以传统的“无痛”康复方法进行锻炼。观察A、B、C三组患者膝关节主动屈伸角度、WOMAC骨关节炎指数评分和临床疗效。结果①A组、B组膝关节主动屈伸角度均大于对照组C,且差异具有统计学意义(P<0.05);②A组、B组的疼痛、僵硬、关节功能评分及WOMAC总分均低于对照组C,差异有统计学意义(P<0.05);③A组的优良率为93.33%,B组为90.00%,对照组C为70.00%,三组比较差异有统计学意义(P<0.05);④A组与B组间疗效比较无显著性差异(P>0.05)。结论髌骨骨折术后采用“量化控制”康复方法治疗,可提高膝关节活动度,减少膝关节疼痛僵硬,恢复膝关节正常生理功能,疗效优于传统无痛康复方法,值得推广。