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Search Results: 1 - 10 of 104257 matches for " Zhang Chengjun "
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Existence and Uniqueness of Solutions for Singular Higher Order Continuous and Discrete Boundary Value Problems
Yuan Chengjun,Jiang Daqing,Zhang You
Boundary Value Problems , 2008,
Abstract: By mixed monotone method, the existence and uniqueness are established for singular higher-order continuous and discrete boundary value problems. The theorems obtained are very general and complement previous known results.
Existence and Uniqueness of Solutions for Singular Higher Order Continuous and Discrete Boundary Value Problems
Chengjun Yuan,Daqing Jiang,You Zhang
Boundary Value Problems , 2008, DOI: 10.1155/2008/123823
Abstract: By mixed monotone method, the existence and uniqueness are established for singular higher-order continuous and discrete boundary value problems. The theorems obtained are very general and complement previous known results.
On the Implication of Tai Chi Diagram and Its Value in Physics  [PDF]
Zixuan Wang, Yanbing Zhang, Chengjun Wu
Open Access Library Journal (OALib Journal) , 2019, DOI: 10.4236/oalib.1105537
Abstract:
As a symbol of Chinese Yin-Yang theory, the implication of Tai Chi diagram has been widely acknowledged in Natural Sciences and Philosophy in both east and west. Taking three well-known principles in physics for example, “the principle of complementarity”, “dissipative structure theory” and “Wheeler’s principle of austerity”, this paper interprets the symbolic rep-resentation of Tai Chi diagram and explores the compatibility between these three modern physical principles and Taoist philosophy. Through the combination of modern physics in the horizon of Tai Chi wisdom, this paper hopes to arouse the continuous attention and reflection of this issue in academic circles.
Positive Solutions of a Singular Positone and Semipositone Boundary Value Problems for Fourth-Order Difference Equations
Chengjun Yuan
Discrete Dynamics in Nature and Society , 2010, DOI: 10.1155/2010/312864
Abstract: This paper studies the boundary value problems for the fourth-order nonlinear singular difference equations , , , . We show the existence of positive solutions for positone and semipositone type. The nonlinear term may be singular. Two examples are also given to illustrate the main results. The arguments are based upon fixed point theorems in a cone. 1. Introduction In this paper, we consider the following boundary value problems of difference equations: Here and . We will let denote the discrete integer set , and denotes the set of continuous function on (discrete topology) with norm . Due to the wide applications in many fields such as computer science, economics, neural network, ecology, and cybernetics, the theory of nonlinear difference equations has been widely studied since the 70's of last century. Recently, many literatures on the boundary value of difference equations have appeared. We refer the reader to [1–13] and the references therein, which include work on Agarwal, Elaydi, Eloe, Erber, O'Regan, Henderson, Merdivenci, Yu, and Ma et al., concerning the existence of positive solutions and the corresponding eigenvalue problems. Recently, the existence of positive solutions of fourth-order discrete boundary value problems has been studied by several authors; for example, see [14–16] and the references therein. On the other hand, fourth-order boundary value problems of ordinary value problems have important application in various branches of pure and applied science. They arise in the mathematical modeling of viscoelastic and inelastic flows, deformation of beams and plate deflection theory [17–19]. For example, the deformations of an elastic beam can be described by the boundary value problems of the fourth-order ordinary differential equations. There have been extensive studies on fourth-order boundary value problems with diverse boundary conditions via many methods, for example, [20–26] and the references therein. We also find that the differential equations on time scales is due to its unification of the theory of differential and difference equations, see [27–30] and the references therein. In this paper, the boundary value problem (1.1) can be viewed as the discrete analogue of the following boundary value problems for ordinary differential equation: Equation (1.2) describes an elastic beam in an equilibrium state whose both ends are simply supported. However, very little is known about the existence of solutions of the discrete boundary value problems (1.1). This motivates us to study (1.1). In this paper, we discuss separately the cases
On Linguistic Environment for Foreign Language Acquisition
Chengjun Wang
Asian Culture and History , 2009, DOI: 10.5539/ach.v1n1p58
Abstract: It is clear that children acquire their first language without explicit learning. A foreign or second language is usually learned but to some degree may also be acquired or “picked up” depending on the environmental setting. So, this article mainly discusses the linguistic environmental setting for foreign language acquisition. It suggested that we should make an effective linguistic environment for foreign language acquisition in foreign language classroom.
Comparative analyses of leaf anatomy of dicotyledonous species in Tibetan and Inner Mongolian grasslands
JianJing Ma,ChengJun Ji,Mei Han,TingFang Zhang,XueDong Yan,Dong Hu,Hui Zeng,JinSheng He
Science China Life Sciences , 2012, DOI: 10.1007/s11427-012-4268-0
Abstract: Knowledge of the leaf anatomy of grassland plants is crucial for understanding how these plants adapt to the environment. Tibetan alpine grasslands and Inner Mongolian temperate grasslands are two major grassland types in northern China. Tibetan alpine grasslands occur in high-altitude regions where the low temperatures limit plant growth. Inner Mongolian temperate grasslands are found in arid regions where moisture is the limiting factor. Few comparative studies concerning the leaf anatomy of grassland plants of the Tibetan Plateau and Inner Mongolian Plateau have been conducted. We examined leaf characteristics at 71 sites and among 65 species, across the alpine grasslands of the Tibetan Plateau and the temperate grasslands of the Inner Mongolian Plateau. We compared the leaf structures of plants with different life forms and taxonomies, and their adaptation to arid or cold environments. We explored relationships among leaf features and the effects of climatic factors (i.e., growing season temperature and precipitation) on leaf characteristics. Our results showed that (i) there were significant differences in leaf anatomy between Tibetan alpine and Inner Mongolian temperate grasslands. Except for mesophyll cell density, the values obtained for thickness of leaf tissue, surface area and volume of mesophyll cells were larger on the Tibetan Plateau than on the Inner Mongolian Plateau. (ii) Within the same family or genus, leaf anatomy showed significant differences between two regions, and trends were consistent with those of whole species. (iii) Leaf anatomy of woody and herbaceous plants also showed significant differences between the regions. Except for mesophyll cell density, the values obtained for the thickness of leaf tissue, and the surface area and volume of mesophyll cells were larger in herbaceous than in woody plants. (iv) Leaf anatomical traits changed accordingly. Total leaf thickness, thicknesses of lower and upper epidermal cells, and surface area and volume of mesophyll cells were positively correlated, while mesophyll cell density was negatively associated with those traits. (v) Growing season temperature had stronger effects on leaf anatomy than growing season precipitation. Although the communities in Tibetan and Inner Mongolian grasslands were similar in appearance, leaf anatomy differed; this was probably due to the combined effects of evolutionary adaptation of plants to environment and environmental stress induced by climatic factors.
MICRO-/MACRO-SCOPIC MODELING OF SOLUTAL MASS TRANSPORT IN DENDRITE SOLIDIFICAfION WITH PARTIAL SOLID BACK DIFFUSION
任意固相反扩散条件下枝晶凝固溶质传输微观/宏观模型化

XU Daming,ZHANG Chengjun,SI Guangju,
徐达鸣
,张成军,司广琚

金属学报 , 1998,
Abstract: The continuum model proposed by the present authors for macroscopic solidification transport phenomena and macrosegregation formation was extended to account for the effect of any incomplete solid back diffusion through a microscopic dendrite solidification model. A generalized coefficient for the solid back diffusion was proposed by the present microscopic/macroscopic model, which includes the growing dendrite dimension, the parameters for the dendrite geometry, the solidification rate and partition coefficient etc besides the solid diffusivity.Numerical simulation of macrosegregations in a horizontal directionally soliditied A1-4.4Cu ingot with assumed different solid diffusivities of the copper solute was performed using the extended continuum model. The computation results show that the variation of the solid back diffusion can evidently influence the macrocomposition distribution in the soliditied ingot, and the greater the solid solute diffusivity, the lighter the macrosegregation seventy.
Characterization and Comparative Profiling of MicroRNAs in a Sexual Dimorphism Insect, Eupolyphaga sinensis Walker
Wei Wu, Qiuping Ren, Chengjun Li, Yanyun Wang, Ming Sang, Yi Zhang, Bin Li
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0059016
Abstract: Background MicroRNAs are now recognized as key post-transcriptional regulators in animal ontogenesis and phenotypic diversity. Eupolyphaga sinensis Walker (Blattaria) is a sexually dimorphic insect, which is also an important source of material used in traditional Chinese medicine. The male E. sinensis have shorter lifecycles and go through fewer instars than the female. Furthermore, the males have forewings, while the females are totally wingless. Results We used the Illumina/Solexa deep sequencing technology to sequence small RNA libraries prepared from the fourth-instar larvae of male and female E. sinensis. 19,097,799 raw reads were yielded in total: 7,817,445 reads from the female library and 11,280,354 from the male, respectively. As a result, we identified 168 known miRNAs belonging to 55 families as well as 204 novel miRNAs. Moreover, 45 miRNAs showed significantly different expression between the female and the male fourth-instar larvae, and we validated 10 of them by Stem-loop qRT-PCR. Some of these differentially expressed miRNAs are related to metamorphosis, development and phenotypic diversity. Conclusions/Significance This is the first comprehensive description of miRNAs in E. sinensis. The results provide a useful resource for further in-depth study on molecular regulation and evolution of miRNAs. These findings not only enrich miRNAs for hemimetabolans but also lay the foundation for the study of post-transcriptional regulation on the phenomena of sexual dimorphism.
Digital Logarithmic Airborne Gamma Ray Spectrometer
GuoQiang Zeng,QingXian Zhang,Chen Li,ChengJun Tan,LiangQuan Ge,Yi Gu,Feng Cheng
Physics , 2014, DOI: 10.1088/1674-1137/38/7/076001
Abstract: A new digital logarithmic airborne gamma ray spectrometer is designed in this study. The spectrometer adopts a high-speed and high-accuracy logarithmic amplifier (LOG114) to amplify the pulse signal logarithmically and to improve the utilization of the ADC dynamic range, because the low-energy pulse signal has a larger gain than the high-energy pulse signal. The spectrometer can clearly distinguish the photopeaks at 239, 352, 583, and 609keV in the low-energy spectral sections after the energy calibration. The photopeak energy resolution of 137Cs improves to 6.75% from the original 7.8%. Furthermore, the energy resolution of three photopeaks, namely, K, U, and Th, is maintained, and the overall stability of the energy spectrum is increased through potassium peak spectrum stabilization. Thus, effectively measuring energy from 20keV to 10MeV is possible.
Analysis of Clinicopathological Feature and Prognosis for ?Leptomeningeal Metastasis in Non-small Cell Lung Cancer
Min ZHU, Yanhong REN, Yan LIU, Chengjun BAN, Hua GU, Zheng WANG, Yuhui ZHANG
- , 2016, DOI: : 10.3779/j.issn.1009-3419.2016.08.09
Abstract: Background and objective Leptomeningeal metastases (LM) is one of the most serious complications of advanced non-small cell lung cancer (NSCLC) due to the lower quality of life and poor prognosis. The aim of this study is to analyze the clinicopathological features and prognosis of patients with LM from NSCLC (NSCLC-LM). Methods Clinical data of 3 patients with NSCLC-LM collected from January 2015 to June 2016 were analyzed with a brief review. Results All 3 patients had adenocarcinoma histology harboring epidermal growth factor receptor (EGFR) exon 21 point mutations (m). Of the 3 cases, 1 was male, 2 were female. The mean age was 61.3 years (range, 59-64 years). The main clinical manifestations and positive physical examination included headache (3/3), dizziness (3/3), nausea (3/3) and vomiting (3/3), epilepsy (2/3), diplopia (1/3), hearing loss (1/3) and meningeal stimulation sign (3/3). The median time from symptom to diagnosis of LM was 2.3 months (range, 1 to 4 months). Except 1 patient with lung cancer and LM diagnosised at the same time, the other 2 cases received the diagnosis of LM after tyrosine kinase inhibitors (TKIs) therapy or chemotherapy respectively, the median time from diagnosis of NSCLC to LC was 8.5 months. The brain enhanced magnetic resonance imaging (MRI) manifestations of all 3 cases revealed linear meningeal enhancement. Cerebrospinal fluid in 3 cases were positive cytology in whom two cases had EGFR exon 21 L858R mutations, consistenting with the lung tissue. The symptom of the 2 cases improved after TKIs therapy, and temozolomide was used as supplement of 1 case of which the progression-free survival (PFS) and overall survival (OS) was 4.9 months and 13.9 months respectively. Conclusion Lung adenocarcinoma with sensitive EGFR mutations are likely to appear LM. Lacking of typical symptoms, NSCLC-LM was easily to be missed and misdiagnosed. TKIs therapy combined with temozolomide may be effective therapies for EGFRm-NSCLC-LM patients.
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