西北干旱区湖泊沉积物中长链烯酮的古环境意义

近年来,U37K&#39;长链烯酮古温度指标已被越来越多地应用于湖泊沉积物的研究中。综合分析我国西风区的湖泊沉积物记录,U37K&#39;对全新世暖期的记录存在较大差异,甚至有高达0.9的异常值出现,即湖泊表层水温在全新世超过30℃,这在气候意义上很难解释。为了更好地理解U37K&#39;在西北干旱区湖泊沉积物中的应用条件,文章对玛纳斯湖西岸的三处晚全新世湖滨沉积物钻孔进行了有机地球化学分析,首次确认了新疆玛纳斯湖湖泊沉积物中存在长链烯酮。通过分析U37K&#39;记录与长链烯酮含量的关系,并与其他西风区湖泊烯酮记录进行对比,发现长链烯酮的含量与干旱区湖泊的湖水位变化存在一定的关系,即长链烯酮含量的高低指示着湖水位的高低; 同时,U37K&#39;记录与长链烯酮含量也存在一定的联系:异常高的U37K&#39;值总是伴随着较低的烯酮含量(&lt;100ng/g干样),即产生于湖滨相或湖泊接近于干涸状态。由此,本文认为湖水位较低时,湖泊水体差异升温和长链烯酮的选择性分解可能是导致较高U37K&#39;出现的原因; 这样的U37K&#39;记录是不可靠的,不能用于定量计算古温度,但仍可用于反应冷暖趋势的变化。</p

福州盆地全新世沉积物的磁学性质及其对环境变化的响应

福州盆地位于海陆过渡地带，在海陆变迁过程中，沉积物记录了高分辨率的环境信息，是揭示沉积特征对 环境变化响应过程及模式的理想区域． 本文选择位于福州盆地的 ＦＺ５钻孔进行岩石磁学、环境磁学和古地磁学方 面的研究，以期阐明该区域沉积物磁学性质对陆源碎屑输入、海平面变化和成岩作用的响应． 岩石磁学结果表明钻 孔沉积物以低矫顽力的亚铁磁性矿物为主体，但是在不同的环境变化阶段，磁性矿物的类型有较大变化． 在９～ ３ｃａｌ． ｋａＢＰ的海侵过程中，沉积物中以磁铁矿为主体，存在菱铁矿和铁硫化物等还原性矿物． 硫化作用使细粒磁 铁矿溶解形成胶黄铁矿和黄铁矿，其峰面随碎屑磁性矿物的浓度变化而迁移． 但硫化作用没有完全消除磁铁矿携 带的特征剩磁和陆源碎屑输入量以及海平面升降对该阶段沉积物磁性的控制． 在～３ｃａｌ． ｋａＢＰ 以来随着海平面 下降、沉积环境向陆相氧化环境转化，虽然早期还原作用仍然存在，但后期氧化作用使磁性矿物向高矫顽力的赤铁 矿等矿物转变，氧化作用基本扰乱了磁铁矿携带的剩磁． 沉积及其后期成岩作用过程中，发生在约～８．２、～７．７、 ～７．５、～２．７、～１．５、～０．５ｃａｌ． ｋａＢＰ六次强烈的古氧化界面反映了福州盆地当时异常干旱或湿热的气候事件

模糊PID控制器在浸出车间石蜡加热器温度 闭环控制中的应用Application of fuzzy PID controller in temperature closed-loop control of paraffin heater in leaching workshop

石蜡加热器是浸出车间石蜡尾气回收工艺中的重要设备，石蜡加热器温度闭环系统是典型的非线性、时变、不确定性系统，难以建立精确的数学模型。为提高石蜡加热器电动调节阀温度闭环控制效果，以检测石蜡加热器的温度偏差（e）和温度偏差变化率（ec）为输入，模糊PID控制器的KP、KI、KD为输出，构造了二输入三输出的模糊PID控制器。以西门子S7-300 PLC为下位机，WINCC组态软件为上位机，采用STEP 7软件编写模糊PID控制的算法程序，并将程序下载到S7-300 PLC存储卡中,利用S7-300 PLC对电动调节阀开度进行调节，从而实现石蜡加热器温度闭环控制。模糊PID控制器应用于浸出车间石蜡加热器温度闭环控制系统可以减少系统超调量，具有响应速度快、稳定性高等优点，提高了石蜡加热器温度闭环控制系统的运行效率。 Paraffin heater is an important equipment of paraffin vent gas recovery process in leaching workshop. The temperature closed-loop system of paraffin heater is a typical nonlinear, time-varying and uncertain system, which is difficult to establish an accurate mathematical model. In order to improve the temperature closed-loop control effect of electric regulating valve of paraffin heater, taking the temperature deviation e and temperature deviation change rate ec of paraffin heater as inputs and KP, KI and KD of fuzzy PID controller as outputs, a two input three output fuzzy PID controller was constructed. Taking Siemens S7-300 PLC as the lower computer and WINCC configuration software as the upper computer, the algorithm program of fuzzy PID control was compiled with STEP 7 software, and the program was downloaded to S7-300 PLC memory card. S7-300 PLC was used to adjust the opening of electric regulating valve, so as to realize the temperature closed-loop control of paraffin heater. The fuzzy PID controller applied to the temperature closed-loop control system of paraffin heater in leaching workshop can reduce the overshoot of the system, and has the advantages of fast response speed and high stability, thus improving the operating efficiency of the temperature closed-loop control system of paraffin heater

中链甘油三酯对高蔗糖饮食豚鼠在负透镜诱导下近视的保护作用Preventive effect of medium-chain triacylglycerol against negative lens-induced myopia in guinea pigs with high sucrose diet

为通过营养学手段防控近视提供参考，研究了中链甘油三酯对高蔗糖饮食豚鼠近视的保护作用。将3周龄豚鼠随机分为中链甘油三酯组（MCT组）、长链甘油三酯组（LCT组）、高蔗糖组（SD组）、正常膳食组（CD组）和对照组（CON组），前三组分别饲喂MCT+高蔗糖饲料、棕榈油+高蔗糖饲料、高蔗糖饲料，CD组和CON组饲喂正常饲料。喂养4周后，分析其屈光度及胰岛素抵抗情况。随后对除对照组外各组豚鼠右眼以负透镜诱导近视造模，左眼作为自身对照。造模5周后测定各组豚鼠的双眼屈光度、胰岛素抵抗水平和血甘油三酯水平。结果表明：高蔗糖饮食各组豚鼠均在4周后出现胰岛素抵抗情况，受负透镜诱导各组豚鼠实验眼在诱导5周后均出现高度近视；高蔗糖饮食各组豚鼠的胰岛素抵抗水平及血甘油三酯水平均高于对照组；高蔗糖饮食各组豚鼠实验眼的近视程度与正常膳食组有显著性差异；MCT组较LCT组和SD组，在胰岛素抵抗水平、右眼受负透镜诱导的近视程度及血甘油三酯水平方面均较低。综上，高蔗糖饮食会使豚鼠产生胰岛素抵抗，加剧负透镜诱导对豚鼠近视性屈光不正的影响，而MCT对高蔗糖饮食加剧的豚鼠受负透镜诱导下的近视有保护作用。In order to provide a reference for the prevention and control of myopia through nutritional means, the protective effect of medium-chain triacylglycerol (MCT) on myopia in guinea pigs with high sucrose diet was investigated. Three-week-old guinea pigs were randomly divided into MCT group, long-chain triacylglycerol (LCT) group, high sucrose (SD) group, normal diet (CD) group and control(CON) group.The first three groups fed with MCT plus high-sucrose feed, olive oil plus high-sucrose feed, simple high-sucrose feed respectively, and the CD and CON groups fed with common feed. After four weeks of feeding, the development of diopters and insulin resistance were analyzed. In the following five weeks, myopia was induced by negative lens in the right eye of each group except the CON group, and the left eye was used as its own control. After five weeks, the changes of binocular diopter and insulin resistance levels of guinea pigs in each group were measured, and the blood triglyceride levels of guinea pigs in each group were also measured. The results showed that all groups on a high-sucrose diet developed insulin resistance after four weeks, and all eyes induced by negative lenses developed high myopia after five weeks of induction. The insulin resistance and blood triglyceride levels were higher in the high-sucrose diet group than in the CON group. The diopter of the experimental eye in the high-sucrose diet group was significantly different from that in the CD group. Compared with the LCT group and SD group, the MCT group was more protected on insulin resistance, negative lens-induced myopia in the right eye, and blood triglyceride levels. In conclusion, a diet with high sucrose can cause insulin resistance in guinea pigs and exacerbate the effect of negative lens induction myopic refractive error in guinea pigs. MCT has a protective effect on lens-induced myopia in guinea pigs exacerbated by high-sucrose diet