强碱性介质中锡酸钠与邻羟基苯酚对铝阳极的协同抑氢作用

The performance of Al-alloy anode in 4 mol/L KOH with and without stannate and o-aminophenol at 25℃and 55℃was studied by hydrogen collection,potentiodynamic polarization and electrochemical impedance spectrum,o-amino- phenol acts as a perfect inhibitor because of its adsorbability and forming chelate complex at its optimum concentration of 0.4 mol/L.Stannate enhances the inhibition of o-aminophenol and improves the activity of Al-alloy because of its reduction to tin.There is synergetic effect of stannate with o-aminophenol on the behavior of Al-alloy,and the inhibitive efficiency at 55℃is better than that at 25℃.     

A note on the Marcinkiewicz integral operators on Fp^a,q

In this paper, we shall prove that the Marcinkiewicz integral operator #n, when its kernel Ω satisfies the L^1-Dini condition, is bounded on the Triehel-Lizorkin spaces. It is well known that the Triehel-Lizorkin spaces are generalizations of many familiar spaces such as the Lehesgue spaces and the Soholev spaces. Therefore, our result extends many known theorems on the Marcinkiewicz integral operator. Our method is to regard the Marcinkiewicz integral operator as a vector valued singular integral. We also use another characterization of the Triehel-Lizorkin space which makes our approach more clear.     

A SISO mixed<Emphasis Type="Italic">H</Emphasis><Subscript>2</Subscript>/l<Subscript>1</Subscript> optimal control problem and its solution

Study of the SISO mixedH ₂/l₁ problem for discrete time systems showed that there exists a unique optimal solution which can be approximated within any prescribed missing error bound inl ₂ norm with solvable suboptimal solutions and solvable superoptimal solutions. Project supported by the National Natural Science Foundation of China (No. 60174026) and the Scientific Research Foundation for Returned Overseas Chinese Scholars of Zhejiang Province (No. J20020546)     

Software Development for Digital Control of WDW Series Testing Machine and Measurement of KIC

Software has been developed for digital control of WDW series testing machine and the measurement of fracture toughness by modularized design. Development of the software makes use of multi-thread and serial communication techniques, which can accurately control the testing machine and measure the fracture toughness in real-time. Three-point bending specimens were used in the measurement. The software operates stably and reliably, expanding the function of WDW series testing machine.     

On some projectively flat polynomial （α,β）-metrics

In this paper, we consider some polynomial (α,β)-metrics, and discuss the sufficient and necessary conditions for a Finsler metric in the form F=α a1β a2β2/α a4β4/α3 to be projectively flat, where ai (i=1,2,4) are constants with a1≠0, α is a Riemannian metric and β is a 1-form. By analyzing the geodesic coefficients and the divisibility of certain polynomials, we obtain that there are only five projectively flat cases for metrics of this type. This gives a classification for such kind of Finsler metrics.     

两个Ramsey数R(m,n,l)和R(m,n,l,s)的含参数的上界

Ｉｎ 1935 ,Ｐ .Ｅｒｄ¨ｏｓａｎｄＧＳｚｅｋｅｒｅｓｏｂｔａｉｎｅｄｔｈｅｃｌａｓｓｉｃａｌｉｎｅｑｕａｌｉｔｙＲ (ｍ ,ｎ)≤Ｒ (ｍ - 1,ｎ) Ｒ(ｍ ,ｎ - 1) .　Ｉｎ 196 8,Ｋ .ＷａｌｋｅｒｐｒｏｖｅｄｔｈａｔＲ(ｎ ,ｎ)≤ 4Ｒ(ｎ- 2 ,ｎ) 2 .　Ｉｎ 1998,ＨｕａｎｇＹ .Ｒ .ａｎｄＺｈａｎｇＫ .Ｍ .[1,2 ] ｐｒｏｖｅｄｔｈａｔＲ(ｍ ,ｎ)≤ 12 (β 3γ 5 ) 　　12 γ(4α 2 β - 3γ 6 ) (β 1) 2　Ｉｎｔｈｉｓｐａｐｅｒ ,ｗｅｏｂｔａｉｎｓｏｍｅｎｅｗｕｐｐｅｒｂｏｕｎｄｓｆｏｒＲ(ｍ ,ｎ ,ｌ)ａｎｄＲ(ｍ …     

Structure and Magnetic Properties of Fe1-xCx Solid Solution Prepared by Mechanical Alloying

Supersaturated solid solutions Fe1-xCx （0≤x≤0.9 ） of wide composition range have been prepared by mechanical alloying process. Nanocrystalline phase was formed for 0 ≤ x ≤ 0.67 and a large grain phase for 0.75 ≤ x ≤ 0.9. The large fraction of graphite volume puts off formation of nanocrystalline phase for high carbon content. In the large grain phase, magnetization follows simple magnetic dilution, and eoereivity He is mainly due to dissolution of carbon at grain boundaries. In the nanocrystalline phase the alloying effect of carbon is revealed by a distinct reduction of average magnetic moment. The increasing lattice constant with increasing carbon content is observed for x ≤ 0.5, suggesting that the high carbon concentration may enhance diffusion of carbon into the Fe lattice. It shows a discontinuity in the Hc variation with a grain size D of nanocrystalline phase. For small grain D below the critical value, Hc increases with D. For a large grain D, Hc decreases with increasing D. The solubility limit of carbon in a-Fe extended by nanocry- stalline phase formation is discussed.     

Nonlinear Riemann Problem for Nonlinear Elliptic Systems in Sobolev Space W1，p（ D ）

The nonlinear Riemann problems were converted into nonlinear singular integral equations and the existence of the solution for the problem was proved by means of contract principle.     

<Emphasis Type="Italic">Negativity</Emphasis> and the <Emphasis Type="Italic">new</Emphasis> in John Dewey’s theory of learning and democracy

Zusammenfassung Negativit?t und das Neue in John Deweys Theorie vom Lernen und der Demokratie — Für einen erneuten Blick auf Lernkulturen Die Rolle des Neuen in Lernprozessen bezieht sich auf die grundlegende Frage, wie Lernen überhaupt m?glich ist und wo es beginnt. In diesem Beitrag wird zun?chst John Deweys Lernkonzeption als Basis für die Analyse entwickelt. Dann wird die Beziehung zwischen Negativit?t und dem Neuen erarbeitet. Beim übergang vom Alten zum Neuen und vom Gewussten zum Ungewussten entstehen Verwirrungen und Schwierigkeiten, die in diesem Papier als Negativit?t im Lernprozess untersucht werden. Au?erdem vermittelt der Beitrag Einsichten in praktische p?dagogische Probleme, etwa bezüglich der Frage, wie Lehrer und andere Erzieher Lernprozesse f?rdern und wie Lernkulturen als besondere Lernumwelten Lehr-Lern-Prozesse unterstützen k?nnen.

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Negativity and the new in John Dewey’s theory of learning and democracy Toward a renewed look at learning cultures

Summary The role of the New in learning processes relates to basic questions of how learning is possible, and where learning begins. Using John Dewey’s concept of learning as the basis for analysis, this inquiry looks into the relation between Negativity and the New and seeks to uncover the negativity in learning processes associated with the perplexities and difficulties which arise in the transitions from Old to New and Known to Unknown. Furthermore, it offers insight into practical pedagogical issues, such as how teachers and educators can support learning processes and how learning cultures, as particular environments for learning, can assist processes of teaching and learning.

     

<Emphasis Type="Italic">Mathematical sophistication</Emphasis> among preservice elementary teachers

This study explores the ways in which eleven preservice elementary teachers used a web-based teacher resource to apply a mathematical definition, to correct a procedural error in arithmetic, and to make sense of a story requiring the multiplication of fractions. In our analysis we propose a framework to compare the behaviors and values expressed by our participants with the values and norms of the mathematical community. This analysis suggests that many preservice elementary teachers are profoundly mathematically unsophisticated. In other words, they displayed a set of values and avenues for doing mathematics so different from that of the mathematical community, and so impoverished, that they found it difficult to create fundamental mathematical understandings.     

Euclid and ‘<Emphasis Type="Italic">The Elements</Emphasis>’

When a crime is committed and the culprit responsible for the crime is nabbed, the job of the investigators is not over. To convince the judge, they have to prove beyond doubt that it was the accused who committed the crime. Likewise, mathematical statements require proofs for their veracity to be established. Further, to make these statements precise we need to have a set of proper definitions. It was Euclid, who more than two thousand years ago, started this tradition when he bequeathed to the world his book entitled The Elements. This tradition has continued since then. Definitions, proofs besides axioms have become an inalienable part of mathematical lore. We owe all this to Euclid, one of the greatest pioneers of rigour and reasoning. In this article we discuss the work of Euclid.     

Electrocatalysis method for wastewater treatment using a novel <Emphasis Type="Italic">beta</Emphasis>-lead dioxide anode

A novel β-PbO₂ anode modified with fluorine resin was developed for typical pollutant electrocatalytic degradation and wastewater treatment. Various operating parameters such as applied voltage (3.5–10.5 V), pH (2–6), salinity of the electrolyte (0.5–2 g/L K₂SO₄) and initial phenol concentration (100–400 mg/L) were investigated to explore the electrocatalytic ability of the anode by taking phenol as sample. A preliminary study on dyeing wastewater treatment by this method indicated that the biodegradability could be increased to suit subsequent biological treatment. The stability of the anode has been proved to be high against acidity. The anode showed promising application for treatment of wastewater, especially of high salinity and high acidity wastewater.     

Mixed G<Emphasis Type="Italic">l</Emphasis><Subscript>2</Subscript>/G<Emphasis Type="Italic">H</Emphasis><Subscript>2</Subscript> multi-channel multi-objective control synthesis for discrete time systems

This paper proposes a new approach for multi-objective robust control. The approach extends the standard generalizedl ₂ (Gl ₂) and generalizedH ₂ (GH ₂) conditions to a set of new linear matrix inequality (LMI) constraints based on a new stability condition. A technique for variable parameterization is introduced to the multi-objective control problem to preserve the linearity of the synthesis variables. Consequently, the multi-channel multi-objective mixed Gl ₂/GH ₂ control problem can be solved less conservatively using computationally tractable algorithms developed in the paper. Project supported by the National Natural Science Foundation of China (No. 60374028), and the Scientific Research Foundation for Returned Overseas Chinese Scholars, Ministry of Education (No. [2004]176)     

5阶KdV方程的一类新多孤子解

Using bilinear transformation method,a new N-soliton solutions were obtained for the Sawada-Kotera equation.