三阶微分方程组边值问题常号解的存在性

利用Krasnonel′skii′s不动点定理,结合Leray-Schauder抉择定理,研究下列三阶微分方程组边值问题um"i(t)=fi(t,u1(t),u2(t),...,un(t)), t∈[0,1],u′i(0)=u″i(0)=ui(1)=0, i=1,2,3,...,n在某些条件下常号解的存在性.

三阶微分方程组边值问题常号解的存在性

利用Krasnoselskii不动点定理,结合Leray-Schauder度,研究下列三阶微分方程组边值问题在某些条件下,常号解的存在性和多解性.

扰动微分方程组解的稳定性

讨论了未被扰动运动的稳定性 ,全局渐进稳定性 ,一致稳定性和一致渐进稳定性 ,给出了相应的充分条件 .

Interpretation of magnetic anomalies by horizontal and vertical derivatives of the analytic signal

Magnetic anomalies are often disturbed by the magnetization direction, so we can＇t directly use the original magnetic anomaly to estimate the exact location and geometry of the source. The 2D analytic signal is insensitive to magnetization direction. In this paper, we present an automatic method based on the analytic signal horizontal and vertical derivatives to interpret the magnetic anomaly. We derive a linear equation using the analytic signal properties and we obtain the 2D magnetic body location parameters without giving a priori information. Then we compute the source structural index （expressing the geometry） by the estimated location parameters. The proposed method is demonstrated on synthetic magnetic anomalies with noise. For different models, the proposed technique can both successfully estimate the location parameters and the structural index of the sources and is insensitive to noise. Lastly, we apply it to real magnetic anomalies from China and obtain the distribution of unexploited iron ore. The inversion results are consistent with the parameters of known ore bodies.

一阶对称形非恰当方程的分组积分因子法

对一阶对称形非恰当方程,提出了先将其左端适当分组,再从其中的某一组的积分因子出发的分组积分因子法,并给出了计算该方程的积分因子的公式化结果,从而扩大了求解一阶对称形方程的范围,简化了其求解方法。此外,亦可运用此法来寻求稳定性问题中的李雅普诺夫V函数,进而根据此V函数的定号性来解决某些非线性驻定方程(组)的零解的稳定性问题,对建立医学数学模型或能发挥作用。

The roles of the proteasome pathway in signal transduction and neurodegenerative diseases

There are two degradation systems in mammalian cells, autophagy/lysosomal pathway and ubiquitin-proteasome pathway. Proteasome is consist of multiple protein subunits and plays important roles in degradation of short-lived cellular proteins. Recent studies reveal that proteasomal degradation system is also involved in signal transduction and regulation of various cellular functions. Dysfunction or dysregulation of proteasomal function may thus be an important pathogenic mechanism in certain neurological disorders. This paper reviews the biological functions of proteasome in signal transduction and its potential roles in neurodegenerative diseases.

Anomalies of bromine in the estuarine sediments as a signal of floods associated with typhoons

X-ray fluorescence scanning with synchrotron radiation was performed to study sediment core records of floods in Amur Bay,Sea of Japan.Interlayers of 3–8 mm with abnormally low bromine content were formed by the Razdolnaya River discharge to the central part of the bay during extreme floods,accompanied by severe storms at sea.Such conditions in the region are typical for periods of deep tropical cyclones(typhoons),to which the distinguished interlayers were compared on the timescale.This approach was made possible thanks to the high rate of sedimentation in the bay(3–5 mm/a) and low bioturbation of sediments under anoxic conditions.

Application of wavelet analysis to fault diagnosis of angular measuring system

For fault diagnosis, signal singularity and irregularity discontinuity fraction are very significant characteristics of signal. The discontinuity of output signal represents a system fault . In an angular measuring system, function transformer uses two D/A convertors, output circuit fault of a D/A convertor brings about discontinuity of one phase input voltage amplitude of inductosyn, results in a system error exceeding the allowable error and reduces the system accuracy. This is the reason why discontinuity is detected. Fourier transform has no resolution ability in angular domain, but wavelet can analyse signal in angular and frequency domains. So we decompose the error signal of angular measuring system by wavelet, detect the signal singularity at high frequency layer and find out the accurate position of it.

Propagation of Smooth Pulses in Anomalously Dispersive Media

In the present letters we study the propagation of smooth pulses in anomalously dispersive media. We prove that non-analytical but smooth points in a pulse still propagate with the vacuum speed of light, c. It gives an upper limit for signal velocity as well as the non-continuous points of the envelop of a pulse or its derivatives of arbitrary order do.

Variety Characteristics and Cultivation Techniques of Rape Changzayou 3

High-quality hybrid rape Changzayou 3 is a new yellow-seed double-low rape variety with high yield, good resistance to diseases and lodging and high oil content, suitable for winter cropping in central China. Its high-yield cultivation tech- niques are mainly early seeding at proper time, thinning timely, rational close planting, scientific fertilization, control of diseases and pest and weeding.

Fatigue damage evaluation by metal magnetic memory testing

Tension-compression fatigue test was performed on 0.45% C steel specimens.Normal and tangential components of magnetic memory testing signals,Hp(y) and Hp(x) signals,with their characteristics,K of Hp(y) and Hp(x)M of Hp(x),throughout the fatigue process were presented and analyzed.Abnormal peaks of Hp(y) and peak of Hp(x) reversed after loading; Hp(y) curves rotated clockwise and Hp(x) curves elevated significantly with the increase of fatigue cycle number at the first a few fatigue cycles,both Hp(y) and Hp(x) curves were stable after that,the amplitude of abnormal peaks of Hp(y) and peak value of Hp(x) increased more quickly after fatigue crack initiation.Abnormal peaks of Hp(y) and peak of Hp(x) at the notch reversed again after failure.The characteristics were found to exhibit consistent tendency in the whole fatigue life and behave differently in different stages of fatigue.In initial and crack developing stages,the characteristics increased significantly due to dislocations increase and crack propagation,respectively.In stable stage,the characteristics remained constant as a result of dislocation blocking,K value ranged from 20 to 30 A/(m·mm)-1,and Hp(x)M ranged from 270 to 300 A/m under the test parameters in this work.After failure,both abnormal peaks of Hp(y) and peak of Hp(x) reversed,K value was 133 A/(m·mm)-1 and Hp(x)M was-640 A/m.The results indicate that the characteristics of Hp(y) and Hp(x) signals were related to the accumulation of fatigue,so it is feasible and applicable to monitor fatigue damage of ferromagnetic components using metal magnetic memory testing(MMMT).

Electrocardiogram Signal Denoising Using Discrete Wavelet Transform

The most common noises in ECG （electrocardiogram） signal processing are BW （baseline wandering） and the 50 or 60 Hz PLI （power line interferences）. In order to remove these two major source of noises, we have used the recent powerful DWT （discrete wavelet transform） signal processing in ECG signals which are obtained from MIT-BIH Arrhythmia Database. The results indicate that DWT is a good method for filtering noises without changing the morphology of ECG, and can be applied to all types of ECG signals, whether normal or presenting arrhythmias.

Differential Expression of Wnts, β-catenin and E-cadherin in hEFs and Normal, Abnormal Karyotype hES Cells during Culture in vitro

Human embryonic fibroblasts （hEFs） can well maintain the pluripotency in human embryonic stem cells （hESs）. However, recent research and reports indicated that a few of hES cell lines acquired genomic alteration during long-term culture of hES cells in vitro. This will directly restrict the therapy use of hES cells. Wnts are secreted lipid-modified signaling proteins that influence multiple processes ranging from cell proliferation to stem cell loss. Activation of Wnt signaling in many tissues has also been associated with cancer. Unchecked Wnt signaling and loss of cadherin expression can promote tumorigenesis. In this study, we found the caryotype of one hES cell line chHES-3 changed with duplication of 1 p32-1p36 area after 34 passages. The results of RT-PCR indicated Wnt7a was expressed in hEFs after culture normal karyotype hES cells, but not expressed in control and abnormal karyotype hES cells. Wnt3 was expressed in hEFs after culture abnormal karyotype hES cells, not expressed in control and normal karyotype hES cells. Wnt3, Wnt9a and WntlOb were detected weakly expression in normal hES cells, but higher in abnormal hES cells. At the same time, Wnt3a, Wnt4, Wnt5b, Wnt7a, Wnt8b and Wnt11 were expressed and E-cadherin was not tested in abnormal hES cells compared with normal hES cells. All that indicated Wnt7a was need for culture normal karyotype hES cells and Wnt3 was need for culture abnormal karyotype hES cells on hEFs. Wnt3, Wnt9a and WntlOb high expression in hES cells and absence of E-cadherin may cause hES cells karyotype change.

Sub-ODE's New Solutions and Their Applications to Two Nonlinear Partial Differential Equations with Higher-Order Nonlinear Terms

In the present paper, with the aid of symbolic computation, families of new nontrivial solutions of the first-order sub-ODE F12 = AF2 ＋ BF2＋p ＋ CF2＋2p （where F1= dF/dε, p 〉 0） are obtained. To our best knowledge, these nontrivial solutions have not been found in [X.Z. Li and M.L. Wang, Phys. Lett. A 361 （2007） 115] and IS. Zhang, W. Wang, and J.L. Tong, Phys. Lett. A 372 （2008） 3808] and other existent papers until now. Using these nontrivial solutions, the sub-ODE method is described to construct several kinds of exact travelling wave solutions for the generalized KdV-mKdV equation with higher-order nonlinear terms and the generalized ZK equation with higher-order nonlinear terms. By means of this method, many other physically important nonlinear partial differential equations with nonlinear terms of any order can be investigated and new nontrivial solutions can be explicitly obtained with the help of symbolic computation system Maple or Mathematics.

几类非线性系统零解的全局稳定性

讨论若干个二阶、三阶和四阶非线性系统零解的全局渐近稳定性.从相应的线性系统的Ляпунов函数出发,构造非线性系统的Ляпунов函数,利用这些函数及其全导数的定号性或常号性,导出关于零解全局渐近稳定的结果.

春雨润物细无声——刘岗村民兵之家建设纪事

刘岗村地处河南省社旗县东南部,自然条件较差。刘岗人在全国劳动模范、村党支部书记曹有志的带领下,大干苦干,发展经济,改变落后面貌;重视“民兵之家”建设,促进全村精神文明建设健康发展,刘岗村成为南阳市的一面旗帜。这个村从1982年创建 “民兵之家”以来,16年中,

Abnormal strain changes observed at Guza before the Wenchuan earthquake

An YRY-4 type borehole strainmeter at Guza station on the southwest end of the Longmenshan fault zone recorded anomalous changes from time to time since about one year before the Wenchuan earthquake.The anomaly is characterized by steps and/or asymmetrical pulses of short-periods(minutes-hours).Among about one hundred stations over the mainland of China,only Guza,the nearest one to the seismic area,observed such changes.A self-check function of the strainmeter helps confirm the credibility of the observation.The anomalous signals do not correspond to seasonal changes.The consistency in the sense of strain among long-term,anomalous interfering and coseismic changes suggests that they all resulted from the background tectonic movement.Results of an Overrun Rate Analysis further illustrate a close temporal relevance of the anomaly to the Wenchuan earthquake:its increase before,and decrease after the biggest changes during the main shock.The abnormal changes are attributed to local small-scale fractures with an evidential clue that the only Ms4.5 foreshock near Guza station on February 27,2008 produced the biggest anomalous change.By means of Wavelet Decomposition,it is revealed that longer period portion of the anomaly took place later before the main shock,consistent with the idea that scales of small fractures increase during earthquake preparation process.The anomalous strain changes are analogous to the stress changes observed before the 1976 Tangshan earthquake.

Subacute posttraumatic ascending myelopathy： A case report and review of literature

Subacute posttraumatic ascending myelopathy is a rare disorder, unrelated to syrinx formation or mechanical instability, which may gradually emerge within the first 1-2 weeks after a spinal cord injury and may lead to diagnostic and prognostic dilemmas. We present a case of 24-year-old female with unstable wedge compression fracture of Ll vertebrae with signal changes in the upper lumbar cord causing complete paraplegia below D9 with bladder and bowel involvement. In the subsequent week, she developed a delayed progressively increasing neurological deficit with cord signal abnormality on MRI extending cephalad from the injury site to the upper dorsal cord. The patient had no initial clinical improvement initially but showed a delayed recovery over months.