Research on the Effects of Institutional Liquidation Strategies on the Market Based on Multi-agent Model

Based on the multi-agent model, an artificial stock market with four types of traders is constructed. On this basis, this paper focuses on comparing the effects of liquidation behavior on market liquidity, volatility, price discovery efficiency and long memory of absolute returns when the institutional trader adopts equal-order strategy, Volume Weighted Average Price (VWAP) strategy and Implementation Shortfall (IS) strategy respectively. The results show the following: (1) the artificial stock market based on multi-agent model can reproduce the stylized facts of real stock market well; (2) among these three algorithmic trading strategies, IS strategy causes the longest liquidation time and the lowest liquidation cost; (3) the liquidation behavior of institutional trader will significantly reduce market liquidity, price discovery efficiency and long memory of absolute returns, and increase market volatility; (4) in comparison, IS strategy has the least impact on market liquidity, volatility and price discovery efficiency, while VWAP strategy has the least impact on long memory of absolute returns.

     

基于螺旋挤压-GVL/水/酸两步预处理的溶解浆联产糠醛和木质素

针对目前溶解浆生产过程中存在的半纤维素和木质素利用率低、溶解浆质量有待提升等问题,本研究基于螺旋挤压耦合γ-戊内酯（GVL）/水/酸预处理,提出绿色环保的溶解浆联产糠醛和木质素的工艺。结果表明,桉木经螺旋挤压-GVL/水/酸两步预处理（150 ℃下反应1.5 h）,蒸煮用碱量8%,漂白工艺OQP₁P₂,制备出α-纤维素含量为96.5%、白度为84.0%的高品质溶解浆;水解液分离木质素后,以甲基异丁基酮（MIBK）/H₂O-NaCl为催化体系,商业离子交换树脂为催化剂,于180 ℃下催化木糖水解液2 h,糠醛最大得率为96.0%;GVL木质素S/G比为4.81,保留一定含量的β-O-4键（22.6%）。经物料衡算,每100 g桉木可生产37.2 g溶解浆、6.2 g糠醛（理论值10.2 g）和16.4 g的GVL木质素。     

低酸喷雾协同蒸汽爆破预处理对小麦秸秆结构及酶水解的影响

研究了低酸喷雾协同低温蒸汽爆破（以下简称汽爆）预处理条件对小麦秸秆纤维的化学组分、结构及酶水解效率的影响。结果表明,在5%硫酸浓度（料液比1∶1）、汽爆反应温度170 ℃（0.79 MPa）、反应时间5 min预处理条件下,纤维素保留率达91.3%,半纤维素脱除率达83.4%,水解液糖得率为80.1%;对预处理后小麦秸秆进行酶水解反应72 h,可获得84.9%的葡萄糖酶解率。本研究提出的低温汽爆预处理农业秸秆的方法,可实现纤维素的高保留率并获得优异的酶水解效率。     

尾矿库埋入式传感器不锈钢外壳腐蚀研究

针对尾矿库埋入式监测仪器或传感器在不同的地下环境中腐蚀严重、经济损失大等问题,采用挂片浸泡、扫描电镜(SEM)、失重法和电化学测试相结合的方法研究了传感器外壳材料(以316L不锈钢为研究对象)在酸性环境和盐卤环境中的腐蚀规律。结果表明,在pH1.5的酸性腐蚀环境中,不锈钢试样短期内钝化膜处于逐渐形成状态,耐蚀性越来越好;经过长期1 a浸泡腐蚀后,耐蚀性略微有所降低;在pH3的硫酸与卤水混合液和pH7.5盐卤水的腐蚀环境中,不锈钢试样短期内耐蚀性越来越好;经过长期浸泡腐蚀后,由于盐卤水中侵蚀性Cl-的存在加速了钝化膜的溶解和破坏,耐蚀性下降幅度明显增大。     

五强溪水电站的枢纽布置及三大建筑物的设计特点

五强溪水电站的总体布置是根据工程的各种自然条件及三大建筑物的特点进行研究的，并以泄洪消能为中心进一步优化设计，确定了最终的枢纽布置方案，该电站采用宽尾墩－底孔－消力池联合消能工，这在国内是首次。     

一种利用中子瞬发伽马能谱确定含油饱和度方法及数值模拟

剩余油饱和度的定量解释对于提高油气产能及指导油田后期开发具有重要意义。脉冲中子饱和度测井通过记录地层中C、O原子核与高能中子作用产生的特征伽马射线来确定剩余油饱和度。骨架矿物组成和粘土矿物类型等因素的变化会使剩余油饱和度解释结果存在误差。为确定岩性对非弹能谱中碳窗和氧窗伽马计数比（C/O）、俘获能谱中硅窗和钙窗伽马计数比（Si/Ca）的影响,采用蒙特卡罗方法（MCNP）模拟不同岩性、孔隙度和饱和度地层条件下的伽马能谱。模拟结果显示：传统碳氧比解释模型进行碳氧比差值计算时未考虑岩性影响,是造成剩余油饱和度解释存在误差的主要原因。通过在碳氧比差值计算时引入岩性校正因子,提出一种改进的碳氧比解释模型,提高饱和度解释精度。模拟算例和实测结果表明,该改进碳氧比解释模型满足砂岩地层饱和度解释精度要求的同时,在混合岩性地层计算饱和度误差小于10%。     

一种感光栅GaN基高电子迁移率晶体管紫外探测器

利用GaN基高电子迁移率晶体管(HEMT)的栅控特性和铁电体的光伏效应机制,制备了一种新型(光敏感层/HEMT)光探测器件。主要研究了复合薄膜和溅射气氛对光敏感薄膜的光伏性能以及对新型感光栅极探测器的光探测能力的影响。结果表明,PZT/ZnO复合薄膜的量子效率峰值达到14.55%;有氧氛围下制备的PZT薄膜剩余极化强度达到52.31μC/cm²;沉积PZT/ZnO复合薄膜的探测器在紫外光照下相比于暗场下的源漏饱和电流最多增加12.64mA。可见,所制备的新型探测器对紫外光具有优良的探测能力,为光探测的研究提供了新的方向。     

Changes in functional properties of common carp (Cyprinus carpio) myofibrillar protein as affected by ultrasound-assisted freezing

Ultrasound-assisted freezing (UF) has proven to be a method that can effectively increase the freezing rate of frozen food and improve its quality. The functional properties of myofibrillar proteins (MP) are important factors that affect the further processing quality of meat products. At present, the effect of UF on the functional properties of frozen MP is not yet clear. Therefore, in the present study, changes in the functional properties (emulsifying and gel properties) of MP in common carps (Cyprinus carpio) frozen with UF at different power levels were investigated. The results revealed that, compared with immersion freezing (IF), UF at 175 W (UF-175) effectively inhibited the decrease in protein solubility, absolute Zeta potential, emulsion activity index, storage modulus (G'), and loss modulus (G'') caused by freezing. UF-175 sample had lower protein turbidity, and smaller protein particle size than any other frozen samples (P < 0.05), which suggested that UF-175 inhibited protein aggregation induced by freezing. In addition, shorter T₂₁ and T₂₂ relaxation times were obtained in UF-175 sample than other frozen samples, indicating that UF-175 reduced the mobility of immobilized and free water. Accordingly, UF-175 sample had higher gel strength and water holding capacity than other frozen samples (P < 0.05). A denser and more uniform gel network structure was also found in UF-175 sample than other frozen samples. In general, improved functional properties of common carp MP can be achieved by optimal UF.     

无规微支化微交联缔合聚合物的合成及性能评价

为了提高聚丙烯酰胺驱油剂的耐温抗盐性能,采用分子结构设计思路,从高分子的一级、二级结构入手对 聚合物结构进行设计,对高分子的高级结构、分子链聚集状态进行分析整合,以AM、AMPS为主要单体,引入自 制的疏水单体和枝化单体合成了一种无规微支化微交联缔合聚合物,采用正交试验方法研究了AM与AMPS物 质的量比、支化单体加量、疏水单体加量、pH值和引发温度对聚合物黏度的影响,并研究了该聚合物的耐温抗盐 性能。研究结果表明,各因素对聚合物黏度影响的主次关系为：支化单体加量＞疏水单体加量＞AM/AMPS配比 ＞体系pH值＞引发温度。当AM、AMPS物质的量比为5∶1,支化单体加量为0.5‰,疏水单体加量为1‰,体系 pH值为7,引发温度为2 ℃时合成聚合物溶液具有最高的黏度。合成的无规微支化微交联缔合聚合物具有较高 的特性黏数（2868 mL/g）、更低的不溶物含量（0.12%）、更高的聚合物黏度、更优异的热稳定性能,在矿化度40 000 mg/L、95 ℃高温老化180 d 后,质量浓度为1500 mg/L 的聚合物溶液黏度为12.8 mPa·s,黏度保留率可达到 85%以上。老化后无规微支化微交联缔合聚合物溶液仍可满足驱油剂对驱油黏度要求,聚合物溶液在地层具有 较优异的长期稳定性。     

130 t单嘴精炼炉真空室内覆盖脱硫渣的钢液流场数值模拟

用Fluent软件和VOF模型模拟了130 t单嘴精炼炉内覆盖脱硫渣时钢包底吹氩流量(150～450L/min)和吹氩位置(中心至3/4浸渍管半径)对钢渣界面平均速度的影响。结果表明,吹气位置为1/2浸渍管半径(R)处最合理,钢渣界面平均速度随吹气流量的增加而增加,当流量一定时吹气位置为1/2R时界面平均速度最大;吹气位置﹥1/2R时才会对界面上渣相体积分数变化有显著影响。