Spatial variation law of vertical derivative zero points for potential field data

In this paper we deduce the analytic solutions of the first- and second-order vertical derivative zero points for gravity anomalies in simple regular models with single, double, and multiple edges and analyze their spatial variation. For another simple regular models where it is difficult to obtain the analytic expression of the zero point, we try to use the profile zero points to analyze the spatial variation. The test results show that the spatial variation laws of both first- and second-order vertical derivative zero points are almost the same but the second-order derivative zero point position is closer to the top surface edge of the geological bodies than the first-order vertical derivative and has a relatively high resolution. Moreover, with an increase in buried depth, for a single boundary model, the vertical derivative zero point location tends to move from the top surface edge to the outside of the buried body but finally converges to a fixed value. For a double boundary model, the vertical derivative zero point location tends to migrate from the top surface edge to the outside of the buried body. For multiple boundary models, the vertical derivative zero point location converges from the top surface edge to the outside of the buried body where some zero points coincide and finally vanish. Finally, the effectiveness and reliability of the proposed method is verified using real field data.

Variation Law of Pericarp Tenderness of Super Sweet Corn Kernel

To investigate the variation law of pericarp tenderness in growth progress of super sweet corn kernel, the values of pericarp tenderness of 10 super sweet corn inbreeds were measured during kernel growth, and the variations under differ- ent conditions were analyzed. The results showed that there existed gradient differ- ences in pericarp tenderness among the 10 materials, of which PE10 had the best pericarp tenderness, T105 took medial place, and $33205 performed worst in peri- carp tenderness. Pericarp tenderness values of these 3 inbreeds increased curvedly from 12 to 24 days after pollination, in the spring （Wuhan, Hubei） and winter （Ling- shui, Hainan） of 2014. Moreover, the average pericarp tenderness at different time points presented the same decreasing order of $33205, T105, PE10, which was not altered by enviroment. With the growth of kernel, for one material, the difference of pericarp tenderness under different environments presented a law of increment, re- duction, uniformity. As for optimum-picking time, there was four days difference be- tween the spring in Wuhan and winter in Lingshui. However, there was no obvious difference in pericarp tenderness on the optimum picking time, which indicated that growing environment could affect the variation ratio of pericarp tenderness, but it still depended on the nature of materials.

Variation law of gas holdup in an autoclave during the pressure leaching process by using a mixed-flow agitator

The multiphase reaction process of pressure leaching is mainly carried out in the liquid phase. Therefore, gas holdup is essential for the gas–liquid–solid phase reaction and the extraction rate of valuable metals. In this paper, a transparent quartz autoclave, a six blades disc turbine-type agitator, and a high-speed camera were used to investigate the gas holdup of the pressure leaching process. Furthermore, experiments determining the effects of agitation rate, temperature, and oxygen partial pressure on gas holdup were carried out. The results showed that when the agitation rate increased from 350 to 600 r/min, the gas holdup increased from 0.10% to 0.64%. When the temperature increased from 363 to 423 K, the gas holdup increased from 0.14% to 0.20%. When the oxygen partial pressure increased from 0.1 to 0.8 MPa, the gas holdup increased from 0.13% to 0.19%. A similar criteria relationship was established by Homogeneous Principle and Buckingham's theorem. Comprehensively, empirical equation of gas holdup was deduced on the basis of experimental data and the similarity theory, where the criterion equation was determined as ε=4.54×10^(-11)n^(3.65)T^(2.08)P_g^(0.18). It can be seen from the formula that agitation rate made the most important impact on gas holdup in the pressure leaching process using the mixed-flow agitator.

Variation law of microscopic pore of loess-like soil after several freeze-thaw cycles in seasonal frozen soil region

In seasonal frozen soil region,the engineering geological properties of loess-like soil will be deteriorated after freeze-thaw cycles.Through the freeze-thaw cycle experiment of remolded loess-like soil,under different freezing temperatures,the authors carried out freeze-thaw cycle tests for 3 times and 20 times,respectively.With mercury intrusion porosimetry and granulometric analysis,from the micro-structure,the authors studied the law that freeze-thaw cycle times and frozen temperature effect on the variation of microscopic pore of loesslike soil.This result can provide theoretical basis for comprehensive treatment of problems in the construction of the project in seasonal frozen loess-like soil region.

The Variation Law of the Market Price of Pork in Beijing City

In order to research the fluctuation law of price of pork in Beijing City and determine its fluctuation cycle,we use level indicator analysis,speed indicator analysis,the coefficient of variation,the seasonal adjustment model and the HP filter method,to analyze the data on the market price of pork in 8 wholesale markets in Beijing City during the period 2002-2011.The results show that the annual price of pork in wholesale markets in Beijing City shows a gradual upward trend;during the period 2002-2011,the price of pork in Beijing City experienced three full fluctuation cycle,and each fluctuation cycle was roughly 38 months;the price of pork within the year shows a trend of " one trough,one crest",and the interval of high prices is mainly concentrated in June-december;the amount of pork for sale within the year is basically inversely correlated with the price.Therefore,we should strengthen the monitoring of pig production information and market information,to ensure the sufficient supply of pork,and stabilize the market price of pork.In addition,according to the variation law of the market price of pork,improving the purchasing,storage and allocation work mechanism of the reserve meat is also necessary to stabilizing the market price of pork.

PECULIARITIES OF LONG TERM VARIATION OF SEA SURFACE TEMPERATURE IN TROPICAL WESTERN PACIFIC OCEAN

It is necessary to study the tropical western Pacific SST in association with variations of other parts of the globe. Two basic compositions are revealed of long-term variation in SST over three major tropical oceans since the 1950’s (linear warming and El Ni?o-La Ni?a oscillations) and typical patterns with which they are displayed over the oceans are compared. On the basis of it, difference in long-term variation of SST over western, central and eastern tropical Pacific is analyzed in details. It is pointed out that the El Ni?o-La Ni?a oscillations are relatively weak in the long-term variation of SST in the tropical western Pacific and linear warming trend there is replaced by interdecadal oscillations. Further understanding of the peculiarity over the region helps improve short-term climatic predictions in China.

Perceptual Contrast-Based Image Fusion: A Variational Approach

本地对比，或变化，在主要是从来源图象保存重要信息到熔化结果的图象熔化起一个重要作用。威伯的法律告诉我们在不同背景下面的一样的变化将引起不同感性的感情，因此，一个理想的图象处理器不得不考虑视觉心理学和心物学的效果。这份报纸考虑人的视觉系统(HVS ) 的性质并且从每幅来源图象把量的感性的变化转移到结果。把 just-noticeable-difference (JND ) 用作测量， multiband 图象的感性的对比作为一个目标被获得。我们构造一个功能的极值问题发现一幅单身的乐队图象，或熔化结果，它有最近感性的对比到目标一个。经由变化途径， Euler-Lagrange 方程被导出，并且一次坡度降下重复被采用。试验性的结果证明这个方法感性地好。

DYNAMIC VARIATION OF NITROGEN CONTENT IN THE SECOND SONGHUA RIVER

The space time variation laws of nitrogen content in different river sections, water periods and years in the Second Songhua River in China is described in detail. The results show that there is direct relation between the nitrogen content variation in river water and that in wastewater from cities and runoff water of both banks of the river. Nitrate and nitrite contents in water in flood period are higher than that in mid and low water periods. In flood period, nitrate content in water increases gradually with the extension of river section, ammonia content in polluted river section is higher than that in unpolluted river section. Nitrate and nitrite contents in water in the flood, mid and low water periods from 1985 to 1989 were slightly higher than that from 1980 to 1984 and from 1990 to 1994, ammonia content in water increased annually.

Multi-symplectic variational integrators for nonlinear Schrdinger equations with variable coefficients

In this paper, we propose a variational integrator for nonlinear Schrodinger equations with variable coefficients. It is shown that our variational integrator is naturally multi-symplectic. The discrete multi-symplectic structure of the integrator is presented by a multi-symplectic form formula that can be derived from the discrete Lagrangian boundary function. As two examples of nonlinear Schrodinger equations with variable coefficients, cubic nonlinear Schrodinger equations and Gross-Pitaevskii equations are extensively studied by the proposed integrator. Our numerical simulations demonstrate that the integrator is capable of preserving the mass, momentum, and energy conservation during time evolutions. Convergence tests are presented to verify that our integrator has second-order accuracy both in time and space.

1949—2021年登陆我国热带气旋历史规律研究

基于1949—2021年中国气象局最佳热带气旋路径数据,按照相应规则筛选出登陆我国的热带气旋及登陆位置,分析研究登陆热带气旋的数量、强度、时间等特征和变化规律,并具体分析沿海各地区登陆热带气旋的变化规律。结果表明:1949—2021年登陆我国的热带气旋数量呈略微减小趋势,有明显的高峰、低谷期,2018年后处于一个较低的水平;热带气旋登陆时的强度主要集中于强热带风暴、台风级别,登陆月份主要集中于7—9月;1949—2021年登陆我国的低强度热带气旋有减小趋势,而高强度热带气旋有增大趋势,说明登陆的高强度热带气旋将会越来越多,这可能与全球变暖以及热带扩展有关;1949—2021年登陆热带气旋位置在纬向上有轻微的南落,经向上无明显变化,这和前人的研究结论不一致,可能是由于选取的数据源以及时间跨度不一致造成的;我国沿海各地区热带气旋登陆频次最高的是广东地区,其次是台湾地区、海南、福建地区,大体上从南到北逐渐减少;台湾地区高强度登陆热带气旋占比最多,其次为浙江、福建、广东、海南地区;长期来看,广东、台湾地区年热带气旋登陆频次呈现减小趋势,浙江、福建地区呈现上升趋势。

Kenics型静态混合器中幂律流体与颗粒混合过程分析

针对Kenics型静态混合器内固体颗粒在幂律流体中的孤岛现象的产生机理进行研究。运用Fluent数值模拟固相颗粒与CMC水溶液在Kenics静态混合器中的混合过程,并利用浓度变异系数(COV)对颗粒分布特性进行量化分析。研究表明:提高流体表观黏度和流体入口速度,颗粒停留时间缩短,COV值降低,混合效果提高。在第4~8个扭旋叶片中间截面上均形成了两对对称的无粒子孤岛,降低流体表观黏度和提高流体入口速度,孤岛边界更清晰。扭旋叶片诱导的内流涡旋和近壁面涡旋有较高的涡量,涡旋中心局域形成无粒子孤岛,相邻叶片交错区域,随着涡旋耗散孤岛消失。

储气库固井水泥石渗透率演化规律

固井水泥石渗透率是影响储气库长效密封的关键参数。利用超低渗气体渗透率测量仪,文中对水泥石开展了不同围压和恒定围压、升降有效应力下的渗透率测试,分析了不同压力条件对水泥石渗透率的影响机制;采用数学拟合方法,揭示了水泥石渗透率演化规律。研究结果表明:水泥石渗透率随围压增加而降低;围压恒定、有效应力升降过程中,水泥石渗透率先降低后增大,且有效应力降低阶段水泥石渗透率高于其升高阶段,水泥石内部结构损伤是该差异的主要原因;线性叠加法结合现有渗透率模型计算的水泥石渗透率结果偏高,新建的数学模型能够考虑围压和有效应力的影响,可有效预测不同压力条件下的储气库水泥石渗透率变化。研究结果为注采服役期储气库固井水泥石渗透率预测提供了一个新方法,可为储气库固井水泥环渗漏分析提供关键参数。

9个桉树无性系木纤维径向变异研究

为研究不同无性系桉树的木纤维特性和变异规律,采用木材解剖技术,测定9个尾叶桉×巨桉无性系的纤维长度、纤维宽度、纤维双壁厚、长宽比、壁腔比和腔径比等纤维特性指标,分析这些特征在径向上的变异规律。结果显示:9个无性系的纤维长度、宽度、双壁厚、长宽比、壁腔比和腔径比的变异范围分别为899.74~1038.08μm,17.41~20.77μm,8.07~12.13μm,44.15~60.07,0.96~2.04,0.41~0.57;综合分析各纤维指标,DH33-9、LEI9、DH32-22综合指标达到优质纸浆材原料的要求;其中无性系DH33-9还具有长宽比>35,壁腔比<1的特征,可作为优质的纤维原料。研究结果为桉树有针对性的培育以及木材的合理加工利用提供参考和依据。

运城市主要粮食作物灌溉需水量时空变化研究

明确运城市主要粮食作物冬小麦和夏玉米灌溉需水量的时空变化规律,为未来该市灌溉用水的科学配置提供基本参数。基于运城市域内13个气象站点的长期观测资料,利用Penman-Monteith公式确定参考作物蒸散量,结合有效降雨量和作物系数等参数,计算分析了运城市近50 a冬小麦与夏玉米的灌溉需水量及其时空变化特征。结果表明:在研究时段内,冬小麦和夏玉米年灌溉需水量整体均呈现波动式降低的变化趋势,整体降低幅度分别为-0.7和-2.1 mm/(10 a)。冬小麦在4月和5月的灌溉需水量较多,分别为80.5 mm和108.4 mm;夏玉米则为8月份的灌溉需水量最大,约为85.3 mm。冬小麦和夏玉米全生育期的平均灌溉需水量都呈现从东向西逐渐递增的趋势,冬小麦灌溉需水量的变化范围处于283.6~336.8 mm,夏玉米则为165.4~253.9 mm。相关分析结果表明,水汽压差与太阳辐射对运城市冬小麦和夏玉米灌溉需水量的影响较大。运城市冬小麦与夏玉米灌溉需水量在时间上呈波动降低趋势,在空间上则由东向西逐步递增;气温与降水的变化趋势显示运城市的气候正在朝暖湿化方向发展,未来灌溉方案的制定与优化应当予以充分考虑。

白酒中甲醛含量的测定及变化规律初探

为探究乙酰丙酮-稀释法测定白酒中甲醛含量的影响因素及贮存时间内甲醛含量的变化规律,该文以稀释法为主,纯酒样中的甲醛含量为参比,选取3个甲醛浓度的浓香型白酒为研究对象,探究测定过程中的影响因素,并通过重现性和加标回收率对该方法进行验证,最后追踪贮存时间内白酒中的甲醛含量,探究其变化规律。结果显示,乙酰丙酮-稀释法测定白酒中的甲醛含量,当甲醛含量在10 mg/L范围内,取样体积2.5 mL、水为稀释液、显色剂用量2.5 mL,于96℃恒温水浴中显色20 min时,该方法的检出限为0.007 mg/L,定量限为0.021 mg/L,重现性的相对标准偏差<5%,加标回收率在97.89%~114.91%,可满足实际样品的测定范围需求。贮存期间白酒中的甲醛含量的变化趋势相似,整体呈“前涨中缓后稳定”的趋势,但稳定时间大有不同,少则数月,多则2~3年。综上乙酰丙酮分光光度-稀释法测定白酒中甲醛含量,检出限低、重现性好,简单易操作,用时短,可用于白酒中甲醛含量的测定,在中小酒企中推广使用。

煤储层等效有效应力系数变化规律实验研究

煤储层进入饱和气体单相流后,储层有效应力系数的变化规律是正确评估储层渗透性的关键。本文采集不同变质程度的煤岩样品,对不同外界荷载和孔隙压力条件下煤储层的等效有效应力系数进行了研究,结果表明:在孔隙压力一定的条件下,外界荷载对煤储层等效有效应力系数具有负效应,随外界荷载加载,煤储层等效有效应力系数减小,且外界荷载越大负作用越强;在外界荷载一定条件下,随孔隙压力增加,煤储层等效有效应力系数增大,孔隙压力对煤储层等效有效应力系数具有正效应;相对于中阶煤和高阶煤储层,低阶煤储层由于孔隙类型多样,孔隙尺度大,储层的等效有效应力系数在外界荷载和孔隙压力耦合作用下影响程度相对较小。由于煤储层等效有效应力系数在不同外界荷载和孔隙压力下差异较大,煤储层进入饱和气体单相流后,在不考虑解吸收缩效应条件下,煤储层的有效应力变化并非等同于储层孔隙压力的变化,而与煤阶类型、地应力高低和孔隙压力大小密切相关,原位高地应力条件下,由于煤储层的等效有效应力系数较小,随孔隙压力降低,煤储层有效应力变化相对微弱。

黔南州2017-2022年流感监测资料流行病学分析

目的分析黔南州2017-2022监测年度流感的流行病学特征,发现其变异规律,为科学防控流感提供依据。方法对“中国流感监测信息系统”中2017-2022年黔南州流感监测哨点医院采集并录入的门急诊流感样病例(ILI)及流感网络实验室的病原学监测数据,以流感监测年度为周期进行统计分析。结果2017-2022监测年度共采集ILI咽拭子标本5554例,总核酸阳性率为12.15%(675例);检出阳性率最高为乙型Victoria系(BV),为5.78%,最低为乙型Yamagata系(BY),为0.63%;2017-2018年和2019-2020年两个监测年度呈双峰流行特点,有秋、冬春季或夏、冬春季流行;2018-2019、2020-2021和2021-2022三个监测年度呈单峰流行,仅有冬春季流行期,时间集中在次年的1~3月;人群ILI阳性病例主要集中在5~14岁年龄段。结论黔南州流感仍呈季节性流行,2017-2018监测年度新甲型H1N1、甲型H3N2、BY和BV四种型别均引起不同程度的流行,且交替共存,2018年3月后BY基本消失,2020-2021和2021-2022两个监测年度以BV为绝对的优势株流行,同时应警惕已经消失两年的甲型H3N2亚型在2022年3月的突然出现可能引起新一轮的流行。中小学生是流感防控的主要人群,应重点关注学校等人群密集场所,推广流感疫苗接种与预防流感的知识宣传,降低流感的发病率。

3D立体格栅–砂界面剪切性状试验研究

为探究土工格栅–砂界面的剪切律、强度律和体变律,基于3 D打印技术制作的土工格栅,通过改进的应变控制式直剪仪进行了不同横肋数量的土工格栅与不同干湿类型的标准砂间的界面剪切试验。结果表明:法向应力越大,剪切应力弱化现象越明显,界面抗剪强度及其指标与横肋数量成正比例关系;3 D立体格栅–湿砂界面粘聚力随着横肋数量的增多而减小。3 D立体格栅–干砂界面抗剪强度及其指标比3 D立体格栅–湿砂界面大,剪胀特性更明显。干砂和湿砂均表现出剪胀的体变行为,且横肋数量越多,剪胀特性越明显。研究成果可为探究3 D土工格栅在实际工程中的应用提供参考。

城市污水处理厂进水水质规律分析及应用

利用城市污水处理厂的实际运行数据,分析水质变化情况及水质指标关联度,总结水质水量的变化规律,为后续污水处理提标改造提供定量依据。结果表明,该污水厂进水流量、NH_(3)-N、TN和TP等指标季节因素起决定性影响,季节因素对COD、BOD_(5)的影响较小。通过对城市污水处理厂进水水质分析,掌握污水厂进水情况,可为污水处理厂设计和运行提供基础数据,也可为其他类似工程提供可供借鉴的思路。

巨厚坚硬岩层运移对采场超前支承压力影响实验研究

为了揭示采场超前支承压力在受巨厚坚硬岩层运移影响之后的演化规律和变异特征,以杨柳煤矿典型巨厚坚硬岩层赋存条件为模型,运用物理模拟和机械模拟实验方法进行模拟研究,并与无巨厚坚硬岩层的采场模型进行比较。通过研究发现:采场中巨厚坚硬岩层对其支承压力的影响,主要集中在巨厚坚硬岩层发生破断之前,其应力集中程度高、影响范围广、影响程度剧烈;临近巨厚坚硬岩层破断前,覆岩中有巨厚坚硬岩层时的超前支承压力峰值和影响范围分别为无巨厚坚硬岩层时的1.15倍和1.9倍;巨厚坚硬岩层处于稳定状态时或已发生破断后,采场支承压力峰值和影响范围相对无巨厚坚硬岩层采场较小,对采场超前支承压力的影响相对较弱;支承压力峰值的增大势必会使采场前方煤壁的影响范围增大。