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A unique type of inverted pyramid defect with diameter ～650 nm was observed.


The average β grain diameter (～5 μm) is about two orders of magnitude smaller than that obtained by conventional solid state solution and quench treatment.


The use of mineral oil resulted in the smallest droplet diameter (～1.5 μm) while isopropyl myristate resulted in the largest droplet diameter (～3 μm).


Isothermal flow of He II in circular glass and metal tubes of inner diameter ～0.2 mm is investigated.


These experiments have been done using Vycor porous glass as the channel (average diameter ～70 ?) at temperatures down to 16 mK.

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 A right hallow circular cylinder of quartz having its generator parallel to the principal axis liberates electricity when subjected to torsion about its axis. Charges of opposite signs appear on the inner and outer surfaces. When torsion is applied in the same sense as that of the optical rotation, positive electricity is developed on the outer surface, and vice versa. The quantity of electricity produced by the action of a couple of moment C on a hollow quartz cylinder of external diameter d0, internal... A right hallow circular cylinder of quartz having its generator parallel to the principal axis liberates electricity when subjected to torsion about its axis. Charges of opposite signs appear on the inner and outer surfaces. When torsion is applied in the same sense as that of the optical rotation, positive electricity is developed on the outer surface, and vice versa. The quantity of electricity produced by the action of a couple of moment C on a hollow quartz cylinder of external diameter d0, internal diameter di and length l is klC/do dodi), where k is equal to 9.2x108 in absolute C. G. S. electrostatic units.  割水晶成一圆柱,圆柱之轴即为晶体之光轴,在圆柱之中心穿一孔道,使成一空心圆柱壳,以金属箔敷於圆柱壳内外侧面成两电极。当圆柱之一端固定,一端被扭,则两电极发生异号而等量之电荷,扭转之方向既易,内外两极电荷之号亦互易。若扭力偶矩左旋,则左旋水晶柱之外极得正电;若扭力偶矩右旋则右旋水晶柱之外极得正电。 吾人曾由实验测定水晶圆柱之长短l,内外直径d_i及d_0之大小,与由扭偶矩C所生电量q之关系式如次: q=k(l/(d_0(d_0d_i)))C式中K为一常数,在C.G.S.绝对静电单位制中等於9.2×10~(8)。  Lecocq first found that the sensitivity of diphenylcarbazide test for molybdate ions in mineral acid medium was 1:2.6×10~5 (it is assumed that he used com mercial ammonium molybdate),and SchmitzDumont reported a value of 1:2 ×10~6 in acetic acid solution.In the present investigation,it is found that the sensitivity is still higher (1:5×10~7) when the test is carried out in the neutral medium (and in test tubes with an inner diameter of 10 mm).Evidently the sensitivity is greatly influenced by the concentration... Lecocq first found that the sensitivity of diphenylcarbazide test for molybdate ions in mineral acid medium was 1:2.6×10~5 (it is assumed that he used com mercial ammonium molybdate),and SchmitzDumont reported a value of 1:2 ×10~6 in acetic acid solution.In the present investigation,it is found that the sensitivity is still higher (1:5×10~7) when the test is carried out in the neutral medium (and in test tubes with an inner diameter of 10 mm).Evidently the sensitivity is greatly influenced by the concentration of hydrogen ions. The use of the dipbenylcarbazide as a qualitative reagent for tungstate ions has not yet been recorded before.It is found that in the neutral medium the sensitivity of the test is 0.1[D]~5,which is the same as that for molybdate under similar conditions.  本文报告在中性溶液中,对称二苯基碳酰二胼对钨、钼的灵敏度,两者都是1:5×10~7,或以0.1[D]~5表示之。钨、钼酸根的灵敏度随溶液中氢离子的多寡而不同。  Fineness modulus (F. M.) has served as an index of fineness of aggregates since it was first introduced by Prof. Duff A. Abrams in 1918. In the concrete mix design, the F. M. of sand governs the sand content and hence the proportions of other ingredients. But there are undesirable features in F. M.: it does not represent the grading of sand and manifests no significant physical concept.Prof. suggested an "average diameter" (d_(cp)) in 1943 as a measure of fineness of sand. In 1944, d_(cp) was adopted in... Fineness modulus (F. M.) has served as an index of fineness of aggregates since it was first introduced by Prof. Duff A. Abrams in 1918. In the concrete mix design, the F. M. of sand governs the sand content and hence the proportions of other ingredients. But there are undesirable features in F. M.: it does not represent the grading of sand and manifests no significant physical concept.Prof. suggested an "average diameter" (d_(cp)) in 1943 as a measure of fineness of sand. In 1944, d_(cp) was adopted in 278144 as national standard to specify the fine aggregate for concrete in USSR. It was introduced to China in 1952 and soon becomes popular in all technical literatures concerning concrete aggregates and materials of construction.After careful and thorough investigation from ordinary and special gradings of sand, the equation of d_(cp) appears to be not so sound in principle and the value of d_(cp) computed from this equation is not applicable to engineering practice. The assumption that the initial average diameter (ν) of sand grains between consecutive seives is the arithmetical mean of the openings is not in best logic. The value of an average diameter computed from the total number of grains irrespective of their sizes will depend solely on the fines, because the fines are much more in number than the coarses. Grains in the two coarser grades (larger than 1.2 mm or retained on No. 16 seive) comprising about 2/5 of the whole lot are not duly represented and become null and void in d_(cp) equation. This is why the initiator neglected the last two terms of the equation in his own computation. Furthermore, the value of d_(cp) varies irregularly and even inversely while the sands are progressing from fine to coarse (see Fig. 4).As F. M. is still the only practical and yet the simplest index in controlling fineness of sand, this paper attempts to interpret it with a sound physical concept. By analyzing the F. M. equation (2a) in the form of Table 9, it is discovered that the coefficients (1, 2…6) of the separate fractions (the percentages retained between consecutive seives, a1, a2…a6) are not "size factors" as called by Prof. H. T. Gilkey (see p. 93, reference 4), but are "coarseness coefficients" which indicate the number of seives that each separate fraction can retain on them. The more seives the fraction can retain, the coarser is the fraction. So, it is logical to call it a "coarseness coefficient". The product of separate fraction by its corresponding coarseness coefficient will be the "separate coarseness modulus". The sum of all the separate coarseness moduli is the total "coarseness modulus" (M_c).Similarly, if we compute the total modulus from the coefficients based on number of seives that any fraction can pass instead of retain, we shall arrive at the true "fineness modulus" (M_f).By assuming the initial mean diameter (ν') of sand grains between consecutive seives to be the geometrical mean of the openings instead of the arithmetical mean, a "modular diameter" (d_m), measured in mm (or in micron) is derived as a function of M_c (or F. M.) and can be expressed by a rational formula in a very generalized form (see equation 12). This equation is very instructive and can be stated as a definition of mqdular diameter as following:"The modular diameter (d_m) is the product of the geometrical mean ((d_0×d_(1))~(1/2) next below the finest seive of the series and the seive ratio (R_s) in power of modulus (M_c)." If we convert the exponential equation into a logarithmic equation with inch as unit, we get equation (11) which coincides with the equation for F. M. suggested by Prof. Abrams in 1918.Modular diameter can be solved graphically in the following way: (1) Draw an "equivalent modular curve" of two grades based on M_c (or F. M.) (see Fig. 6). (2) Along the ordinate between the two grades, find its intersecting point with the modular curve. (3) Read the log scale on the ordinate, thus get the value of the required d_m corresponding to M_c (see Fig. 5).As the modular diameter has a linear dimension with a defin  細度模數用為砂的粗細程度的指標,已有三十餘年的歷史;尤其是在混凝土的配合上,砂的細度模數如有變化,含砂率和加水量也要加以相應的調整,才能維持混凝土的稠度(以陷度代表)不變。但是細度模數有兩大缺點,一個是模數的物理意義不明,另一個是模數不能表示出砂的級配來。蘇聯斯克拉姆塔耶夫教授於1943年提出砂的平均粒徑(d_(cp))來,以為砂的細度指標;雖然平均粒徑仍不包含級配的意義,但是有了比較明確的物理意義,並且可以用毫米來度量,這是一種新的發展。不過砂的細度問題還不能由平均粒徑而得到解决,且平均粒徑計算式中的五項,僅首三項有效,1.2和2.5毫米以上的兩級粗砂在計算式中不生作用,以致影響了它的實用效果。本文對於平均粒徑計算式的創立方法加以追尋和推演,發現其基本假設及物理意義,又設例演算,以考察其變化的規律性;認為細度模數還有其一定的實用價值,不能為平均粒徑所代替。至於補救細度模數缺點的方法,本文試由模數本身中去尋找;將模數的計算式加以理論上的補充後,不但能分析出模數的物理意義,並且還發現模數有細度和粗度之別。根據累計篩餘計算出來的F.M.應稱為“粗度模數”,根據通過量計算出來的才是“細度模數”。假定兩隣篩间的顆粒是... 細度模數用為砂的粗細程度的指標,已有三十餘年的歷史;尤其是在混凝土的配合上,砂的細度模數如有變化,含砂率和加水量也要加以相應的調整,才能維持混凝土的稠度(以陷度代表)不變。但是細度模數有兩大缺點,一個是模數的物理意義不明,另一個是模數不能表示出砂的級配來。蘇聯斯克拉姆塔耶夫教授於1943年提出砂的平均粒徑(d_(cp))來,以為砂的細度指標;雖然平均粒徑仍不包含級配的意義,但是有了比較明確的物理意義,並且可以用毫米來度量,這是一種新的發展。不過砂的細度問題還不能由平均粒徑而得到解决,且平均粒徑計算式中的五項,僅首三項有效,1.2和2.5毫米以上的兩級粗砂在計算式中不生作用,以致影響了它的實用效果。本文對於平均粒徑計算式的創立方法加以追尋和推演,發現其基本假設及物理意義,又設例演算,以考察其變化的規律性;認為細度模數還有其一定的實用價值,不能為平均粒徑所代替。至於補救細度模數缺點的方法,本文試由模數本身中去尋找;將模數的計算式加以理論上的補充後,不但能分析出模數的物理意義,並且還發現模數有細度和粗度之別。根據累計篩餘計算出來的F.M.應稱為“粗度模數”,根據通過量計算出來的才是“細度模數”。假定兩隣篩间的顆粒是兩篩篩孔的幾何平均值,以代替數學平均值(即斯氏平均?   << 更多相关文摘 
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