ASYMPTOTIC HOMOGENIZATION IN A PARABOLIC SEMILINEAR PROBLEM WITH PERIODIC COEFFICIENTS AND INTEGRABLE INITIAL DATA

In this paper, we study the large time behavior of solutions of the parabolic semilinear equation δtu-div（a（x）△↓u） = -｜u｜^αu in （0,∞） × R^N, where α 〉 0 is constant and a∈ Cb^1（R^N） is a symmetric periodic matrix satisfying some ellipticity assumptions.Considering an integrable initial data u0 and α ∈ （2/N, 3/N）, we prove that the large time behavior of solutions is given by the solution U（t, x） of the homogenized linear problem δtU-div（a^h△↓U）=0,U（0） = C, where a^h is the homogenized matrix of a（x）, C is a positive constant and δ is the Dirac measure at 0.

Research on the Ideological Origin of the Initial Period of Robot Animation in Japan

Robot animation has played an important role in the development of Japanese animation.Robot animation,as a major pillar of Japanese animation industry,has triggered several changes in Japanese animation industry,successfully guided the dual route of localization and globalization of Japanese animation,and promoted the arrival of the golden age of Japanese animation.In order to reveal the ideological characteristics of robotic animation and the reasons leading the development trend of animation,this paper adopts the historical method,centering on Astro Boy,Mazinger Z and Space Warship Yamato,which are the nodes of animation history,to make a longitudinal investigation and analysis of the initial period of Japanese robot animation.Through this kind of investigation,we can not only make up for the deficiency of the systematic thought research theory of robot animation,but also sort out the development of robotic animation as a whole,and solve the problem of the ideological origin of robotic animation.At the same time,we can also provide a new research perspective for the history of animation communication between China and Japan,which is of great significance to strengthen the communication of animation and cultural exchange between China and Japan.

Explicit One-Step P-Stable Methods for Second Order Periodic Initial Value Problems

In this paper, we present an explicit one-step method for solving periodic initial value problems of second order ordinary differential equations. The method is P-stable, and of first algebraic order and high phase-lag order. To improve the algebraic order, we give a composition second order scheme with the proposed method and its adjoint. We report some numerical results to illustrate the efficiency of our methods.

A TWO-STEP EXPLICIT METHOD FOR A CLASS OF LINEAR PERIODIC INITIAL VALUE PROBLEMS

This paper presents a two-step explicit method of order four for solving aclass of linear periodic initial value problems. At each computational step, only tworight function evaluations and one derivative evaluation are employed. Basing on aspecial vector operation, the method can be extended to the vector-applicable in multi-dimensional space.

Plotting the Clarifying Curves and Determination of the Specific Amount of Settled Material during the Initial Period to Sedimentation in Stationary Column of Aqueous Suspensions of Solids

The present paper presents an algorithm and a program for plotting the clarifying curves and for determination of the specific amount of settled material during the initial period based on data obtained from sedimentation experiments in stationary column of aqueous suspensions of solids particles with different concentrations. The algorithm and program have been developed for an interactive, rapid and convenient processing of the data obtained from sedimentation experiments in stationary column of aqueous suspensions of solids particles and allow obtaining with accuracy of precise and expressive graphs which characterize the behaviour of aqueous suspensions to sedimentation in stationary column. Sedimentation study of different aqueous suspensions of solids particles in stationary column is of great importance for experimentally determining the important parameters required to design and exploitation clarifiers and sludge thickeners from waste water treatment plants.

Large-time Behavior of Solutions for Parabolic Conservation Laws with Large Initial Data

In this paper,we study the large-time behavior of periodic solutions for parabolic conservation laws.There is no smallness assumption on the initial data.We firstly get the local existence of the solution by the iterative scheme,then we get the exponential decay estimates for the solution by energy method and maximum principle,and obtain the global solution in the same time.

TIME-PERIODIC ISENTROPIC SUPERSONIC EULER FLOWS IN ONE-DIMENSIONAL DUCTS DRIVING BY PERIODIC BOUNDARY CONDITIONS

We show existence of time-periodic supersonic solutions in a finite interval, after certain start-up time depending on the length of the interval, to the one space-dimensional isentropic compressible Euler equations, subjected to periodic boundary conditions. Both classical solutions and weak entropy solutions, as well as high-frequency limiting behavior are considered. The proofs depend on the theory of Cauchy problems of genuinely nonlinear hyperbolic systems of conservation laws.

Periodic Revivals of Squeezing in a Mesoscopic Josephson Junction

The fraction between a mesoscopic Josephson junction and a quantized electromagnetic field is discussed quantum mechanically.Within the external field approximation,it is shown that if the Held is prepared in a coherent state and the junction is initially in its lowest energy level,squeezing can occur in such a system.

“一带一路”倡议与全球价值链升级——基于沿线国家的实证数据

基于2007—2020年“一带一路”沿线国家的样本数据,利用多期双重差分模型实证检验了“一带一路”倡议对沿线国家的价值链升级作用。研究结果证实:“一带一路”倡议对于沿线国家全球价值链发展具有显著正向影响。机制分析表明:“一带一路”倡议对沿线国家存在“虹吸效应”,有利于沿线国家的发展。此外,政策沟通对于倡议的推行具有积极的促进作用。研究结果不仅证实了倡议对于沿线国家价值链升级的正向影响,也论证了其中存在的影响机制,为未来进一步的研究提供了理论支撑和有益探索。

基于微震监测的浅埋8 m超大采高综采面矿压规律现场监测研究

以陕北矿区某矿2203浅埋超大采高综采面为工程背景,采用微震监测技术,对浅埋超大采高综采面矿压规律进行了研究。结果表明:单日微震事件数达到峰值后,综采面继续回采8.25~11 m内,能量大于103J的事件增多,微震事件能量及支架压力达到峰值,随后顶板出现垮落现象。综采面初次来压前,微震总能量为6.40×10^(3)J,矿压显现期间为1.07×10^(4)J,总能量增长67%;由于综采面矿压显现与微震最大能量峰值出现一致,通过2次最大能量峰值时综采面位置可以确定综采面周期来压步距。2203综采面初次来压步距为24.75 m,周期来压步距为27~35.25 m,由此确定,顺槽超前支护距离为36 m,实践表明,2203综采面采用ZCZY10300/31/55D型超前液压支架满足巷道超前支护的要求。微震监测是矿压显现规律分析的有效手段,采用液压支架压力变化与微震能量协同分析的方法研究超大采高综采面的矿压规律是可行的。

殷墟王陵四论

本文在前辈学者研究的基础上,进一步指出殷墟王陵始建于洹北商城时期,是洹北商城始建之时都邑格局的重要组成部分。新的考古发现仍说明殷墟王陵废弃于西周早期,这与周革殷命的政治策略有关。王陵东区大量祭祀坑的年代为殷墟早期,特别是武丁时期,大规模祭祀是“武丁中兴”重要的政治举措。以妇好为代表的诸多王族成员死后仍葬于宫殿宗庙区,反映出当时的族邑理念。

混合煤矸放落态势特征研究

传统的基于图像检测技术的放顶煤过程中煤流动态特性研究多侧重于某一特定阶段的图像分析,未结合全阶段的动态特性进行综合分析;现有研究较少将放顶煤过程中上覆岩层的松散区变化与放煤过程中的煤矸分离和煤流特性相结合,缺乏对放煤过程的全局性系统分析。针对上述问题,对放顶煤过程中的煤流动态特性、煤矸分离效果及上覆岩层松散区凹陷变化进行了系统研究。首先,提出了一种基于双光流网络的放顶煤过程动态分析方法。实验结果表明:不同放煤方案下,放煤速度不随放煤形式和规律的变化而改变,平均检测准确率随着放煤口数量的增多而提高,尤其在不同放煤步距阶段呈明显线性增长;顶煤放出率与平均检测准确率呈正相关关系,验证了该方法在放顶煤过程监测中的有效性。其次,利用OpenCV技术对上覆岩层松散区凹陷面积进行实验分析。结果表明,初始放煤阶段松散区凹陷面积急剧增长,随后随时间推移逐渐趋于稳定;通过凹陷面积的动态变化趋势,可有效判断顶煤的放出过程,实现透明化放煤监测。最后,结合称重实验数据,分析了放煤量、放出率与含矸率之间的关系。结果表明,初始放煤阶段纯煤放出量最大,周期放煤阶段纯煤放出量趋于稳定,含矸率则随着放煤口数量的增多而减少。该结果进一步揭示了放煤方式对煤矸分离和顶煤放出率的影响。

松材线虫潜育期延长导致红松越年枯死

【目的】探究红松越年枯死的病理学过程和产生原因,以期为有效除治无松材线虫病症状的携带者松树提供理论依据。【方法】统计抚顺市大伙房实验林场自然侵染红松越年枯死比例,观测自然侵染和人工接种红松病症病状,测定红松当年显症的松材线虫数量阈值。实验室内不同温度下测定松材线虫虫口增长情况,以及媒介昆虫羽化后适宜松材线虫虫口有效增长的时期(虫口增长期),计算从寄生关系的建立到症状开始出现的时间(潜育期),并揭示红松感染松材线虫后越年枯死的原因。【结果】截至6月,自然侵染红松的越年枯死比例为41.4%。观测的自然侵染和低剂量人工接种红松在被侵染或接种当年均未出现显著外部、内部症状变化,而是到翌年松脂分泌停止,树干水分低,针叶变红褐色,只有进行高剂量饱和接种才出现当年半数显症。病症表现为松材线虫能够正常侵染红松,可有效繁殖但在低温时繁殖受阻,可成功越冬但越冬后虫口数量骤减。红松显症的全株阈值St1=(163±22)条·g^(-1),局部阈值St2=(621±20)条·g^(-1)。以每株50000条的接种量接种38年生红松,在当年虫口增长期内全株松材线虫数量仅为(90±8)条·g^(-1),低于St1、局部松材线虫数量最高为(350±18)条·g^(-1),也低于St2。抚顺的虫口增长期(141天)比大连(154天)和南京(173天)短。经计算,抚顺市松材线虫的潜育期为146天,长于虫口增长期。【结论】云杉花墨天牛携带的松材线虫数量相对较低,导致初始侵染量低。松材线虫生命周期受温度特性的影响,表现为非增长期长、虫口增长期短,最终导致在虫口增长期内未能达到红松显症的松材线虫数量阈值。这些综合作用导致松材线虫潜育期延长,其中41.4%的死亡红松表现出越年枯死现象。

The hydrological effect between Jingjiang River and Dongting Lake during the initial period of Three Gorges Project operation

Based on the measured hydrological data from 1951 to 2008, the chain hydrological effect between Jingjiang River and Dongting Lake is analyzed by comparative method after the Three Gorges Project operation. The result indicates that 1） the scouring amount in Jing- jiang River made up 78.9% of the total from Yichang to Chenglingji, and its average scouring intensity was higher than the latter; 2） the water and sand diversion rates at the three outlets of the Jingjiang River were reduced by 2.33% and 2.78% separately; 3） the proportion of multi-year average runoff and sediment through the three outlets in the total into the Dongting Lake decreased by 7.7% and 24.4% respectively; 4） in Dongting Lake, the speed of sediment accumulation was lowered by 26.7%, in flood season, the runoff amount was 20.2% less than the multi-year average value, leading to seasonal scarcity of water year by year. The former prolonged the lake life, while the latter induced droughts in summer and fall in successive years, shortage of drinking and industrial water, shipping insecurity, as well as ecological problems such as decrease of birds and quick increase of Microtus fortis; 5） The multi-year average values of sediment and flood transporting capacity at the lake outlet were respec- tively increased by 26.6% and 3.7%, the adapt to the new change of the river-lake embankments were protected effectively. Then, to relation, some suggestions were put forward, such as optimizing further operation program of the Three Gorges Reservoir, reexamining the idea of river and lake regulation, and maintaining connection of the river and the lake.

我国北方主产省苹果始花期时空模型建立及晚霜冻风险分析

为有效防御晚霜冻灾害对当地苹果生产的影响,本研究选取万荣、白水、礼泉、陕州、福山和熊岳等代表站的苹果始花期物候观测资料和同期气象数据,建立并检验了苹果始花期时空模型,并利用该模型重建了1970—2019年我国北方主产省苹果始花期,分析其时空变化特征;结合晚霜冻气象指标,对苹果花期晚霜冻气候风险情况进行分析。结果表明:(1)建立的苹果始花期模型能够在数据独立的情况下较准确地模拟代表站的始花期变化,内部检验的均方根误差为4.26d,交叉检验的均方根误差为5.00 d;(2)始花期时空模型模拟得到的苹果始花期大多数呈显著提前趋势;(3)苹果花期轻霜冻的发生频率和发生日数均最高,其次是中霜冻,而重霜冻发生频率和日数较低;(4)从空间上看,渤海湾地区苹果晚霜冻发生频率、发生日数指数和气候风险指数较小,而黄土高原北部地区苹果晚霜冻发生频率、发生日数指数和气候风险指数较大。因此,气候变化背景下,黄土高原果区苹果遭受晚霜冻的影响较大,应注意重点防范。

Large-Time Behavior of Periodic Solutions to Fractal Burgers Equation with Large Initial Data

The asymptotic behavior of periodic solutions to fractal nonlinear Burgers equation is considered and the initial data are allowed to be arbitrarily large.The exponential decay estimates of the solutions are obtained for the power of Laplacian α∈[1/2,1).

浅埋煤层矿压显现及支架适应性分析

为了探究浅埋煤层坚硬顶板工作面矿压显现以及验证液压支架的合理性,以庄子河煤矿15107工作面为研究对象,采用理论计算、PFC软件模拟、现场实测相结合的方法,研究该工作面开采过程中矿压显现的规律并开展液压支架适应性研究。结果表明:理论计算15107工作面基本顶初次来压步距约41.56 m,周期来压步距约为16.98 m,与数值模拟、现场实测数据基本一致;对上部、中部和下部支架的工作压力频率进行了分析,结果表明液压支架满足工作面正常开采要求。该研究成果对类似地质条件下探究其矿压显现规律以及工作面液压支架的选型具有一定的借鉴意义。

1950年代南昌工业的发展及其区域分布考察

随着新中国的成立,南昌的工业进入一个新阶段,工业发展与工业布局体现了社会主义工业体系探索时期的特征。南昌的工业在三年国民经济恢复时期,通过接管与没收官僚资本企业、扶持与恢复生产、抗美援朝与民主改革等运动完成了迅速的恢复。到“一五计划”期间,又通过宣传与动员、制定社会主义工业化蓝图、对干部的提拔与培训等措施,完成了工业的全面恢复与发展。全市的冶金、机械、电力、轻工、二轻工、纺织服装鞋帽、化学、食品与建筑材料工业等9个主要工业门类得到了全面的重建与发展。解放初,东湖区、西湖区与青云谱区工厂分布最多,而湾里区、南昌县、新建县、进贤县与安义县则寥寥无几。全市工业分布具有“区域性”“集中性”与“零散性”的特征。

蓄水初期抗力体谷幅变形及对特高拱坝变形的影响

抗力体部位谷幅变形对特高拱坝结构安全性影响较大。以白鹤滩水电站为例,在分析白鹤滩水电站蓄水初期抗力体部位谷幅变形的基础上,采用结构有限元计算方法,分析蓄水初期实际谷幅变形对坝体的影响程度,并分析谷幅变形的分布特征对拱坝变形影响敏感性。结果表明,白鹤滩水电站初蓄期谷幅变形较小,目前谷幅变形对坝体变形影响有限,不同谷幅变形分布形式对特高拱坝影响较为显著,为进一步蓄水提供了理论支撑。

丹寨县龙泉山景区杜鹃始花期预报分析

为满足丹寨县龙泉山景区杜鹃始花期的预报需求,对龙泉山区域自动站2013—2023年的气温、湿度、降水量等气象数据以及始花期数据进行统计分析,探讨了杜鹃始花期预测方法、预测模型的建立及应用。结果表明:最早和最晚始花期时间相隔6 d,始花期有推迟的趋势;始花期受气温、温湿比的影响,且与其呈显著相关性(P<0.05)。以3月下旬平均最低气温为关键气象因子,建立杜鹃始花期预报模型,该模型预测误差为1~3 d,模型预测效果较好。