我国男生引体向上“零”分探因:基于三角互证的研究策略

我国多数男生引体向上得“零”分,使上肢力量测评出现“地板效应”。采用量化研究和质性研究两种范式提高研究效度。量化研究对学生体质与健康调研数据和监测数据进行方差分析、多重比较和回归分析,结果表明:(1)每5~10年,男生的握力、体重、身高、BMI、引体向上均值差异显著;(2)年龄、握力、体重、身高、BMI分别显著预测引体向上成绩,体重和握力是影响我国男生引体向上成绩的主要影响因素。质性研究结果表明,引体向上“零”分主要有四个方面的原因:体重增长难挡,力量增长受限,个体认知偏差,社会支持薄弱。结论:我国男生引体向上“零”分的首要原因是体重增长较快,其次,主要肌群绝对力量和耐力增长不足,男生对引体向上的认知有偏差,学校、家长、社会支持较弱;借助政策控制体重、发展肌力、完善测评标准、促进男生积极练习引体向上十分重要。

Schur Forms and Normal-Nilpotent Decompositions

Real and complex Schur forms have been receiving increasing attention from the fluid mechanics community recently,especially related to vortices and turbulence.Several decompositions of the velocity gradient tensor,such as the triple decomposition of motion(TDM)and normal-nilpotent decomposition(NND),have been proposed to analyze the local motions of fluid elements.However,due to the existence of different types and non-uniqueness of Schur forms,as well as various possible definitions of NNDs,confusion has spread widely and is harming the research.This work aims to clean up this confusion.To this end,the complex and real Schur forms are derived constructively from the very basics,with special consideration for their non-uniqueness.Conditions of uniqueness are proposed.After a general discussion of normality and nilpotency,a complex NND and several real NNDs as well as normal-nonnormal decompositions are constructed,with a brief comparison of complex and real decompositions.Based on that,several confusing points are clarified,such as the distinction between NND and TDM,and the intrinsic gap between complex and real NNDs.Besides,the author proposes to extend the real block Schur form and its corresponding NNDs for the complex eigenvalue case to the real eigenvalue case.But their justification is left to further investigations.

NORMALITY AND THE NUMBER OF ZEROS

In this paper,we study normal families of meromorphic functions.By using the idea in[11],we obtain some normality criteria for families of meromorphic functions that concern the number of zeros of the differential polynomial,which extends the related result of Li,and Chen et al..An example is given to show that the hypothesis on the zeros of a(z)is necessary.

A Capacitor-Free CMOS Low-Dropout Regulator for System-on-Chip Application

A stable CMOS low drop-out regulator without an off-chip capacitor for system-on-chip application is presen- ted. By using an on-chip pole splitting technique and an on-chip pole-zero canceling technique, high stability is achieved without an off-chip capacitor. The chip was implemented in CSMC＇s 0.5μm CMOS technology and the die area is 600μm×480μm. The error of the output voltage due to line variation is less than -＋ 0.21% ,and the quiescent current is 39.8μA. The power supply rejection ratio at 100kHz is -33.9dB, and the output noise spectral densities at 100Hz and 100kHz are 1.65 and 0.89μV √Hz, respectively.

Quantitative Study on Characteristics of the Weibull Distribution

Aim To quantitatively study three characteristics of the Weibull distribution. Methods Theoritical analysis of the three characteristics of parameters of the Weibull distribution was done and mathematics software was used to make some chart analysis. Results 17 equations and 7 figures were made. Conclusion Under the standard form, the class of the Weibull probable density founction(pdf) curves appear double peak shape. Under the standard form, the maximum value point curve of the Weibull pdf takes line t =0 and t=1 as asymptotes. When β = 3 30-3 40, the Weibull distribution is the most similar to the normal distribution.

Asymptotic Stability in the Large of Zero Solution of Second Order Nonlinear Differential Equation

There are many works on the asymptotic stability of second dimensional nonlinear differential equation. In particular, these results only concern with the system which includes one or two terms, whereas few works concern with system which includes more than two terms. In this paper, system which includes four nonlinear terms are studies. We obtain the global asymptotic stability of zero solution, and discard the condition which require the Liapunov function trends to infinity, and only require that the positive orbit is bounded.

Distribution of Zeros of Solutions of Advanced Differential Equations with One Advanced Variable

The distribution of zeros of solutions of the advanced differential equations with an advanced variable x′（t）-P（t）x（τ（t））=0,t≥t0 is studied, where P（t）∈C（[t0,∞）,R^＋）,τ：[t0,∞）→R^＋ are continuously differentiable and strictly increasing,τ（t）≥t and limt→∞τ（t）=∞.The estimate for the distance between adjacent zeros of the oscillatory solution of the above equation is obtained.

Zeros of Differential Polynomial f（z）f（k）（z） -- a and Its Normality

Suppose that function f（z） is transcendental and meromorphic in the plane. The aim of this work is to investigate the conditions in which differential monomials f（z）f（k）（z） takes any non-zero finite complex number infinitely times and to consider the normality relation to differential monomials f（z）f（k） （z）.

A review of rare earth minerals flotation: Monazite and xenotime

This paper reviews rare earth minerals(monazite and xenotime) separation by flotation. A wide range of monazite and xenotime flotation test results are summarized including: reasons of variation in the point of zero charges on these minerals, the effects of various flotation conditions on zeta potential of monazite and xenotime, interactions of collectors and depressants on the surface of these minerals during flotation separation, relationship between surface chemistry of the minerals and different types of collector adsorptions and effects of the conditioning temperature on flotation of rare earth minerals. This review collects various approaches for the selective separation of monazite and xenotime by flotation and gives perspectives for further research in the future.

Pressure-Induced Shifts of R, R＇, and B Line-Groups and Ground-State Zero-Field-Splitting of Ruby

By means of improved ligand-field theory, the 'pure electronic'presure-induced shifts (PS's) and the PS's due to electron-phonon interaction (EPI) of the R_1, R_2,B_1, B_2, B_3, and R′_3 lines and the ground-state zero-Geld-splitting of ruby have been uniformlycalculated. The calculation results are in very good agreement with all the experimental data. Atnormal pressure, ruby is a crystal with very strong crystal field. Thus, the admixture of ∣t_2~2(~3T_1)e~4T_2 】 and ∣t_2~(32)E＞ bases in the wavefunction of R_1 level of ruby is small at normalpressure, and it gradually decreases with increasing pressure, which causes the R_1-line PS of rubyto monotonously red shift with approximate linearity. The combined effect of the pure electronic PSof R_1 line and the PS of R_1 line due to EPI gives rise to the total PS of R_1 line. The analysesand comparisons among the features of R_1-line PS's of three laser crystals (ruby, GSGG:Cr~(3+) andGGG:Cr~(3+)) have been made, and the origin of their difference has been revealed.

An Algorithm for Finding All Isolated Zeros of Polynomial Systems

Finding all zeros of polynomial systems is very interesting and it is also useul for many applied science problems.In this paper,based on Wu's method,we give an algorithm to find all isolated zeros of polynomial systems (or polynomial equations).By solving Lorenz equations,it is shown that our algo-rithm is efficient and powerful.

Research on the Mechanism of Retail Strategy Influencing Consumer Behavior Intention——Based on Empirical Analysis of Domestic Luxury Cosmetics Brands

This is a research on the mechanism of retail strategy mix and consumer behavior intention,and psychological impact on consumer attitude, consumer purchase decision-making model and its components are conducted firstly. Next, retail strategy, merchandise strategy, and store strategy, contained in the retail management theory, are adopted as other important variables to measure the impact on consumer attitudes. And then, the key factors of retail strategy mix are identified by means of Focus Group (FG). In addition, the hypothetical model of retail strategy mix and consumer behavior intention for domestic luxury cosmetic brands is established to understand the relationship between the two factors. Finally, empirical researches are conducted on consumers and retailers of luxury cosmetics brands. And some advice are given on retail strategy mix's influence on the consumer behavior intentions, aiming to enlighten domestic luxury cosmetic enterprises to improve performance by the integrated use of retail strategy mix.

A 16bit 96kHz Chopper-Stabilized Sigma-Delta ADC

A 16bit sigma-delta audio analog-to-digital converter is developed.It consists of an analog modulator and a digital decimator.A standard 2-order single-loop architecture is employed in the modulator.Chopper stabilization is applied to the first integrator to eliminate the 1/f noise.A low-power,area-efficient decimator is used,which includes a poly-phase comb-filter and a wave-digital-filter.The converter achieves a 92dB dynamic range over the 96kHz audio band.This single chip occupies 2.68mm2 in a 0.18μm six-metal CMOS process and dissipates only 15.5mW power.

Novel mutations and sequence variants in exons 3-9 of human T Cell Factor-4 gene in sporadic rectal cancer patients stratified by microsatellite instability

AIM： To establish the role of human T Cell Factor-4 （hTCF-4） gene exons 3-9 mutation status in association with sporadic rectal cancer with microsatellite instability （MSI）. METHODS： Microsatellite markers were genotyped in 93 sporadic rectal cancer patients. Eleven cases were found to be high-frequency MSI （MSI-H）. Sequence analysis of the coding region of the exons 3-9 of hTCF-4 gene was carried out for the 11 MSI-H cases and 10 controls （5 microsatellite stability （MSS） cases and 5 cases with normal mucosa）. The sequencing and MSI identification were used. RESULTS： Several novel mutations and variants were revealed. In exon 4, one is a 4-position continuous alteration which caused amino acid change from Q131T and S132I （391insA, 392 G 〉 A, 393 A 〉 G and 395delC） and another nucleotide deletion （395delC） is present in MSI-H cases （5/10 and 4/10, respectively） but completely absent in the controls.CONCLUSION： Novel mutations in exon 4 of hTCF-4 gene were revealed in this study, which might be of importance in the pathogenesis of sporadic rectal cancer patients with MSI-H.

Value Distribution of a Class of Differential Polynomials

Let f（z） be a transcendental meromorphic function in the complex plane and a ≠0 be a constant, for any positive integer m, n, k, satisfy m ≥ nk＋n＋2, ψ= f^m ＋a（f^（κ））^n has infinitely many zeros. The corresponding normal criterion also is proved.

City Networks of Online Commodity Services in China:Empirical Analysis of Tmall Clothing and Electronic Retailers

City networks have been a critical topic in the fields of urban geography and regional economics. Numerous studies have explored city networks, focusing mainly on infrastructure and industrial networks. Unlike traditional urban network of which the major measuring indexes are population sizes and entity industries, online commodity service networks could reflect well the influencing of emerging economies, especially the Internet economy, on city networks. This study analyzes and reveals structural features of China's city networks through online commodity services, providing the internet economic approach on city networks. Results indicate that the core cities of online commodity service networks are mainly concentrated in eastern coastal areas. In addition, spatial polarization and layer structure of network connections are obvious, descending from the centers in eastern China to peripheral cities in central and western China. Online commodity services of different cities show apparent differences and uncertainties in terms of specialization rates of international connection, which presents a tendency toward diversification. Online commodity service networks are not only associated with goods production, supply, and consumption in physical space but also reflect virtual information, capital, and technology flows, thus providing a new empirical approach for understanding city networks in information and internet economic age.

Analysis and optimization of assembly variations for non-rigid parts

Traditional variation analysis methods are not applicable to non-rigid assemblies due to possible part deformation during the assembly process. This paper presents the use of finite element methods to simulate assembly deformation. The relationship between the parts’ variation and the variation of the key points in final assembly for quality control is set up by calculating the spring back deformation after assembly. Moreover, the optimization method for non-rigid assembly variations based on finite element analysis is presented. The optimal objective is to reduce the manufacturing cost. The approach is implemented by using ANSYS and MATLAB. The test example shows that the proposed method is effective and applicable.

Deterministic Quantum Key Distribution with Pulsed Homodyne Detection

In this paper, we propose a deterministic quantum communication protocol using weak coherent states and pulsed homodyne detection. In this protocol, the communication parties exchange their secret information deterministicaJly in two rounds. The devices and efficiency of the protocol are discussed respectively. We also show the security of the protocol against intercept-resend and Trojan-Horse eavesdropping attacks.

Ass(M/N)and Ann(M/N)on the Noetherian Module M

Let R is a noetherian ring,M is a finitely generated R-module.This paper studies the relation between associated prime Ass(M/N)and annihilator Ann(M/N),and has given the necessary and sufficient conditions of Ass(M/N)=Ann(M/N).

Lyapunov Inequalities of Nonlinear Discrete Systems

In this paper, we study the nonlinear discrete systems and obtain several lyapunov inequalities for them. Then we give the application for lyapunov inequality.