ON HOLOMORPHIC CURVES OF CONSTANT CURVATURE IN THE COMPLEX GRASSMANN MANIFOLD G(2,5)

In this article, it is proved that there doesn’t exist any nonsingular holomorphic sphere in complex Grassmann manifold G（2, 5） with constant curvature k = 4/7, 1/2, 4/9. Thus, from [7] it follows that if φ ： S2 → G（2, 5） is a nonsingular holomorphic curve with constant curvature K, then, K = 4, 2, 4/3, 1 or 4/5.

NORMAL CRITERIA FOR A FAMILY OF HOLOMORPHIC CURVES

In this paper,we extend the concept of holomorphic curves sharing hyperplanes and introduce definitions of restricted hyperplanes and partial shared hypersurfaces.Then,we prove several normal criteria of the family of holomorphic curves and holomorphic mappings that concern restricted hyperplanes and partial shared hypersurfaces.These results generalize the Montel-type normal criterion of holomorphic curves.

Shared Hyperplanes and Normal Families of Holomorphic Curves

In theorem LP [1], Liu proves the theorem when N = 2, but it can’t be ex-tended to the general case in his proof. So we consider the condition that the families of holomorphic curves share eleven hyperplanes, and we get the theorem 1.1.

关于《Asymptotic behaviour of holomorphic strips》一文的注记

在Joel W.Robbin和Dietmar A.Salamon的文章《Asymptotic behaviour of holomorphic strips》中主要结果定理A与定理B的证明中,我们认为有两个关键的地方是不确切的,一个是对引理2.2的第一个不等式的证明,另一个是定理B的证明中使用该文章附录C中的引理C.1.对前一个,我们认为那里方法难以推出,并给出一个证明;对后一个,我们认为那里使用引理不太合适,并给出一个新结果代替它.

Binary Sequences from a Pair of Elliptic Curves

A family of binary sequences were constructed by using an elliptic curve and its twisted curves over finite fields. It was shown that these sequences possess ＂good＂ cryptographie properties of 0-1 distribution, long period and large linear complexity. The results indicate that such se quences provide strong potential applications in cryptography.

基于绝对位移法的曲线梁桥多维多点弹塑性随机响应分析

针对当前地震动空间效应下曲线梁桥地震反应分析多采用确定性激励输入且忽略桥梁非线性的情况,采用了多维多点非平稳随机激励对曲线连续梁桥进行弹塑性响应分析。建立非线性有限元模型并降维解耦非平稳地震动非平稳演化功率谱(energy power spectral density,EPSD)矩阵,采用绝对位移法对桥梁进行非线性时程分析。考虑不同视波速、场地条件、相干性以及平稳与非平稳地震激励,综合分析了曲线连续梁桥的随机响应及其频域特性和时域特性。结果表明,地震动空间效应和地震动的非平稳性对曲线梁桥随机响应影响很大,其中地震动空间效应对桥梁随机响应大小及其频域分布有显著影响,而非平稳性会对随机响应大小及其时变响应趋势产生重要影响。因此,在曲线连续梁桥抗震分析中需充分考虑地震动空间效应和地震动非平稳性,以避免错误估计桥梁抗震性能。提供了全面的分析结果,对加强曲线连续梁桥的抗震设计和评估,从而提高其抗震性能和可靠性具有重要意义。

On Pseudo-Holomorphic Curves from Two-Spheres into a Complex Grassmannian G(2, 5)

Let s ： S2 → G（2, 5） be a linearly full totally unramified pseudo-holomorphic curve with constant Gaussian curvature K in a complex Grassmann manifold G（2, 5）. It is prove that K is either 1 4 1 or 4/5 if s is non-±holomorphic. Furthermore, K = 1/3 if and only if s is totally real. We also prove that the Gaussian curvature K is either 1 or -4/3 if s is a non-degenerate holomorphic curve under some conditions.

基于周期性最大功率点检测的风电机组功率备用控制方法

风电机组通常运行于最大功率输出模式,无法为受扰电网提供紧急功率支撑。稳态时预留部分出力可提高风电机组主动电网支撑能力,为此提出一种基于周期性最大功率点(MPP)检测的风电机组功率备用控制(PRC)方法。通过周期性执行最大功率点跟踪程序检测风电机组实时MPP,一旦检测到MPP即可确定PRC模式参考值并切换为直接功率控制。设置伪单调转速-机械功率曲线使风电机组稳定运行在超速功率备用点,并通过储能装置平抑MPP检测产生的峰值功率波动。仿真结果表明提出的控制方法在定风速和变风速情况下均可以准确控制检测风电机组MPP并实现PRC,并且使得风电机组一次调频效果优于传统PRC。

底水油藏水侵量计算新方法

针对底水油藏的开发,在缺乏试井数据的情况下采用常规油藏物质平衡法以及试井分析方法均难以确定水驱控制储量,进而无法获得水体参数和特征来计算油田的水侵量。为了更加准确的预测水驱油田水侵量,结合生产动态资料,选择符合的水驱特征曲线计算水驱控制储量。在此基础上,考虑油环油、溶解气、水体等因素,建立物质平衡方程,通过亏空体积曲线法计算获得水侵量。利用Fetkvoitch拟稳态模型,采用试错法,优化计算水体体积和水侵系数,保证Fetkvoitch拟稳态模型求解的水侵量和亏空体积曲线法求解的水侵量最接近,得到最优的水体体积和水侵系数对未来生产动态中水侵量进行预测。运用油藏数值模拟软件建立的模型与本文提出两种的计算方法拟合结果对比可知的水体体积的误差为2.6%、水侵指数的误差为2.2%,计算结果准确,为底水油藏计算水侵量提供了可靠的依据,并为预测水侵量提供了新的方法。

基于波形相控反演的致密砂岩储层模拟预测方法——以黄骅坳陷沧东凹陷南部古近系孔二段为例

在岩石物理分析的基础上,利用波形相控反演与模拟相结合的方法,并结合拟声波阻抗重构技术及基于坐标旋转的储层参数指示构建技术,对黄骅坳陷沧东凹陷南部中高斜坡区古近系孔二段的致密砂岩储层进行预测。研究结果表明:(1)波阻抗曲线对于砂岩和泥岩的识别效果较差,而自然伽马能以83 API为界限值有效区分砂岩与泥岩,优选的自然电位曲线不仅能以-13 mV为界限值有效区分砂岩和泥岩,对于储层与非储层也具有一定的区分能力。(2)重构后的拟声波阻抗曲线提高了对砂岩和泥岩的识别能力,基于坐标旋转的储层指示曲线以-10为门槛值划分储层与非储层,且储层指示曲线可实现对致密砂岩储层的预测。(3)波形相控反演与模拟相结合的储层预测方法能够提高致密砂岩储层预测的精度,并可降低储层预测的多解性,储层预测符合率达83.3%。

最佳替代率下石墨尾矿混凝土柱抗震性能拟静力试验

为研究石墨尾矿替代砂子最佳比率及石墨尾矿混凝土柱抗震性能,对4种比率(10%、20%、30%、40%)下石墨尾矿部分替代砂子的混凝土进行了抗压强度、劈裂抗拉强度和静力受压弹性模量等试验,将试验结果与普通混凝土进行对比,确定了石墨尾矿替代砂子的最佳比率,然后以该替代率下的混凝土制作了一个柱试件并进行了拟静力试验,最后根据石墨尾矿混凝土柱破坏特征、滞回曲线、骨架曲线、刚度特性及耗能能力等结果分析了其抗震性能。结果表明:30%替代率下的石墨尾矿混凝土抗压强度和抗拉强度均最高,弹性模量高于其他替代率,且与普通混凝土相差较小,说明30%为最佳替代率;石墨尾矿混凝土柱在低周往复拟静力加载下呈现弯曲破坏特征,滞回曲线饱满圆滑并具有较好延性,且随着加载位移的增加,试件的割线刚度逐渐减小,等效黏滞阻尼比逐渐增大,整体表现出良好的耗能能力和抗震性能。

Degeneracy of holomorphic curves in surfaces

Let X be a complex projective algebraic manifold of dimension 2 and let D1,..., Du be distinct irreducible divisors on X such that no three of them share a common point. Let f: C → X\(U1≤i≤uDi) be a holomorphic map. Assume that u ≥ 4 and that there exist positive integers n1,...,nu, c such that ninj(Di.Dj) = c for all pairs i, j. Then f is algebraically degenerate, i.e. its image is contained in an algebraic curve on X.

Invariant algebraic curves and rational first integrals of holomorphic foliations in CP(2)

In this paper, using the tools of algebraic geometry we provide sufficient conditions for a holomor-phic foliation in CP(2) to have a rational first integral. Moreover, we obtain an upper bound of the degreesof invariant algebraic curves of a holomorphic foliation in CP(2). Then we use these results to prove that anyholomorphic foliation of degree 2 does not have cubic limit cycles.

Weak Cartan-type Second Main Theorem for Holomorphic Curves

In this paper, a weak Cartan-type second theorem for holomorphic curve f ： C→P^n（C） intersecting hypersurfaces Dj, 1≤j≤q, in P^n（C） in general position with degree dj is given as follows： For every ε〉0, there exists a positive integer M such that ｜｜（q - （n ＋ 1） ε）Tf（r）≤∑j^q=1 1/dj Nf^M（r,Dj）＋o（Tf（r））, where ＂｜｜＂ means the estimate holds for all large r outside a set of finite Lebesgue measure.

Effect of the Mesh Transparency on the Electrical Characteristics of DC Pseudo Discharge

A DC pseudo discharge for air has been studied. Air pressure is used in the range between 0.7 Torr and 12 Torr. The breakdown occurs between a plane cathode and a mesh anode at transparencies of 19%, 46%, and 65%. The current-voltage characteristic curves of the discharge, which are measured at different pressures, distances, and mesh transparences, take effect in the region of abnormal glow. The discharge voltage decreases as the air pressure increases, while more voltage is needed to maintain the discharge when either the mesh transparency or the inter- electrode distance is increased. An increment of mesh transparency causes high negative potential behind the mesh due to the high concentration of electrons, which accumulate and collide with neutral atoms. Paschen curves deviate from the expected regular one. The left side of Paschen curves appears at inter-electrode distance of 1 mm, whereas the right side appears at inter-electrode distance of 5 mm. The intermediate region is observed only at 3 mm distance between the two electrodes. For the transparency range used in this work, it is found that the decrement of the breakdown voltage, on the right side, depends on the mesh transparency. For different electrode separations, the measured Paschen curves are coincident and deviate from the standard ones of Paschen＇s law.

Virtual neighborhood technique for moduli spaces of holomorphic curves

We use the technique of Ruan(1999)and Li and Ruan(2001)to construct the virtual neighborhoods and show that the Gromov-Witten invariants can be defined as integrals over the top strata of the virtual neighborhoods.We prove that the invariants defined in this way satisfy all the axioms of Gromov-Witten invariants summarized by Kontsevich and Manin(1994).

Holomorphic Curves into Projective Varieties Intersecting Closed Subschemes in Subgeneral Position

In this paper,the authors introduce the index of subgeneral position for closed subschemes and obtain a second main theorems based on this notion.They also give the corresponding Schmidt’s subspace type theorem via the analogue between Nevanlinna theory and Diophantine approximation.

关于P^(2)(C)上全纯曲线唯一性问题的注记

本文讨论P2(C)中全纯曲线相交处于次一般位置超平面的唯一性.设f1,f2,…,fλ为P2(C)中线性非退化的全纯曲线,H1,H2,…,Hq为P2(C)上处于m-次一般位置的超平面,满足Aj:=f1-1(Hj)=…=fλ-1(Hj)(1≤j≤q)且Ai∩Aj=?(i≠j).假设存在整数l(2≤l≤λ),使得fji(z)∧fj2(z)∧……fji(z)=(z∈quj=1Aj)对任意l个指标1≤j12λ/(λ-l+1)+3/2m时,f1∧…∧fλ≡0.关键技术是第二基本定理中不等式改进为:(q-3m/2)tft(T)≤q∑j=1N2(ft,Hj)(r,0)+o(Tft)(r)(1≤t≤λ).

差分进化算法在岩石孔隙结构研究中的应用

应用岩心核磁共振横向弛豫时间谱研究岩心孔隙结构的核心在于横向弛豫时间与毛管压力的转换系数,传统方法在转换过程中需要用到一些岩石特性参数,实用难度较大。在确定了两者幂函数转换关系的基础上,建立了伪毛管压力曲线转换模型,采用差分进化算法反演得到最佳转换参数,通过文中方法得到的平均孔喉半径、分选系数、排替压力等孔隙结构参数与3块岩心数据进行对比,结果表明,该方法具有较高的准确性,计算的分选参数效果最好,相对误差在2%以内,其他参数相对误差最小的为0.2%,最大的也仅为37%。

伪三元相图联合星点设计-响应面法优选鸦胆子油微乳处方

目的优选鸦胆子油微乳制备工艺。方法优选鸦胆子油微乳由油包水(W/O)型转变为水包油(O/W)型微乳相临界点的测定方法,并初筛微乳油相配比。绘制伪三元相图,筛选最优乳化剂、助乳化剂、油相组成和Km值。以鸦胆子油的用量(%)、Km为考察因素,以微乳的平均粒径(nm)和多分散系数(PDI)为评价指标,采用星点设计-响应面法优选制备工艺。分别从电镜观察、类型鉴别、高速离心(转速为5000 r/min)、室温静置(30 d和60 d)方面考察按最优工艺制备的鸦胆子油微乳的理化性质。结果与目测法相比,电导率-含水量曲线法测定临界点更精确,且微乳的平均粒径和PDI更小,体系更稳定。微乳最优制备工艺为鸦胆子油8.66%、油酸8.66%、聚氧乙烯氢化蓖麻油60.81%、无水乙醇21.87%、Km值为2.78,含水量为71.01%。该工艺下测得微乳的平均粒径为(14.22±0.25)nm,PDI为0.066±0.004。鸦胆子油微乳外观圆整,为O/W型,且稳定性良好。结论该优选工艺操作简便,结果稳定可靠,可为鸦胆子油微乳的工业化生产提供借鉴。