Neues Verfahren zur Messung von Krümmung und Streuwinkeln von Nebelkammerbahnen

Summary A method is described which allows not only to determine the radius of curvature but also to recognize and eliminate impacts at angles larger than 1°, which the particle suffers in the cloud chamber gas. The size of the angles can be determined. It is shown, moreover, that the sum of the squares of the angles of scattering (for unit of length, calculated from the measured angles) is larger by a factor of 10–100 than the one calculated according to theory.     

角度单值-移动合向量长度θ-Rs控制图模拟

以计角值控制图的性能分析为研究出发点，充分借鉴常规控制图性能分析的研究思路，结合圆上闭域的特点，从质量特性值服从VonMises分布这一角度展开分析，运用统计过程控制工具平均链长对计角值控制图中单值-移动合向量长度θ－Rs控制图进行模拟，分析该控制图在发生参数偏移的情况下平均链长的变化。     

The variability of patterns of sexual dimorphism in the hominoid skull

Univariate and multivariate statistical analyses are applied to a number of cranial dimensions and angles from living hominoids in order to investigate the patterns of sexual dimorphism in these groups. Clear differences in patterns of cranial sexual dimorphisms are demonstrated not only between genera but also within a single species (Homo). These differences overlay the common finding of a sexual size difference in all groups. The results imply that caution is required in using the sexual dimorphisms of living hominoids as models for those anticipated in fossils.     

地貌分类指标的钢柔性探索

争对目前地貌类型基本概念的极度混乱现象,文章提出了地貌分类指标的钢柔性方法。该法把直接影响地貌类型基本概念的指标定为钢性指标,把与地貌类型基本概念不密切的指标定为柔性指标,并在此基础上建立了地貌钢柔性分类系统的参考模式,解决了地貌概念的混乱问题,同时增强了地貌分类的灵活性。该结果对促动地貌的生产利用和科学普及有一定作用。     

The variability of patterns of sexual dimorphism in the hominoid skull

Summary Univariate and multivariate statistical analyses are applied to a number of cranial dimensions and angles from living hominoids in order to investigate the patterns of sexual dimorphism in these groups. Clear differences in patterns of cranial sexual dimorphisms are demonstrated not only between genera but also within a single species (Homo). These differences overlay the common finding of a sexual size difference in all groups. The results imply that caution is required in using the sexual dimorphisms of living hominoids as models for those anticipated in fossils.     

Der Eigenartige Einfluß Witelos auf die Entwicklung der Dioptrik

Summary Witelo's Perspectiva, which was printed three times in the sixteenth century, profoundly influenced the science of dioptrics until the Age of Newton. Above all, the optical authors were interested in the so-called Vitellian tables, which Witelo must have copied from the nearly forgotten optical Sermones of Claudius Ptolemy. Research work was often based on these tables. Thus Kepler relied on the Vitellian tables when he invented his law of refraction. Several later authors adopted Kepler's law, not always because they believed it to be true, but because they did not know of any better law. Also Harriot used the Vitellian tables until his own experiments convinced him that Witelo's angles were grossly inaccurate. Unfortunately Harriot kept his results and his sine law for himself and for a few friends. The sine law was not published until 1637, by Descartes, who gave an indirect proof of it. Although this proof consisted in the first correct calculation of both rainbows, accomplished by means of the sine law, the Jesuits Kircher (Ars Magna, 1646) and Schott (Magia Optica, 1656) did not mention the sine law. Marci (Thaumantias, 1648) did not know of it, and Fabri (Synopsis Opticæ, 1667) rejected it. It is true that the sine law was accepted by authors like Maignan (Perspectiva Horaria, 1648) and Grimaldi (Physico-Mathesis, 1665), but since they used the erroneous Vitellian angles for computing the refractive index, they discredited the sine law by inaccurate and even ludicrous results.That even experimental determinations might be unduly biased by the Vitellian angles is evident from the author's graphs of seventeenth century refractive angles. These graphs also show how difficult it was to measure such angles accurately, and how the Jesuit authors of the 1640's adapted their experimental angles to the traditional Vitellian ones. Witelo's famous angles, instead of furthering the progress of dioptrics, delayed it. Their disastrous influence may be traced for nearly thirty years after Descartes had published the correct law of refraction.

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Vorgelegt von C. Truesdell     

Lipid interactions with transmembrane proteins

Magnetic resonance results, principally from ²H-nuclear magnetic resonance, indicate that the mean lipid-chain ordering at the surface of transmembrane proteins is comparable to that in fluid lipid bilayers. Principally, it is the requirement for matching the hydrophobic lengths of lipid and protein that modulates the degree of chain ordering at the lipid-protein interface. The distribution of chain order parameters is, nonetheless, broader in the presence of integral proteins than in fluid lipid bilayers. The chain configurations of the phospholipids that are resolved in crystals of integral membrane proteins display considerable conformational heterogeneity. Chain C–C dihedral angles are, however, not restricted to the energetically allowable trans and gauche rotamers. This indicates that the chains of a given lipid do not have a unique configuration in protein crystals.     

Organization of reflex responses elicited in man by muscle stretch applied to uni- and bi-functional muscles]

The organization of human forearm reflexes following the application of extension torque perturbations has been studied in three flexors of the elbow: brachioradialis (BR), biceps (B), and pronator teres (PT). Two of these flexors are also involved in wrist supination: (B) and pronation (PT). During the perturbation, the wrist was fixed at various angles: from full supination to full pronation. The results show that the amplitude of the reflex responses of B and PT is highly dependent on wrist position. By eliminating biceps length changes as a source of observed reflex variation, it has been shown that the normalized reflex amplitude of B increases by 300% when the wrist position is varied from full pronation to full supination. In contrast, the BR muscle has a reflex response which is independent of wrist position. These results are discussed in relation to the role of reciprocal innervation and the possible action of receptors encoding wrist angle.     

下送风空调系统送风口气流方向对室内气流分布的影响分析

一个设计良好的下送风空调系统具有改善热舒适性、通风效率和室内空气品质,减少能耗、建筑周期花费和层高等优点。本文通过对某一下送风空调系统在送风方向分别与地面之间的夹角（记为a）为0°、45°和90°的条件下,进行了数值模拟计算。分析了不同送风方向时室内气流分布的不同。研究结果表明：a为0°和45°时的室内气流分布类似,室内最大速度都贴近地面。且形成的涡位于室内高度1／2以下,45°时室内产生更多的涡流;a为90°时靠近地面处流速很小,形成的涡位于室内高度1／2以上。对a为0°的情况进行了水模型试验,试验现象表明近地面处速度的分布与模拟计算结果基本吻合。研究结果对预测和控制下送风空调系统的扬尘有理论意义。     

Das Parallelenproblem im Corpus Aristotelicum

Summary In the Corpus Aristotelicum are numerous items suggesting that the assertion of the fifth postulate in Euclid's Elements had been preceded by attempts to demonstrate this postulate itself, or some equivalent fundamental proposition, within the rigorous frame of Absolute Geometry in Bolyai's sense. Thus geometers contemporary with Aristotle tried to solve the problem which became known commonly in later centuries as the Problem of Parallels.Probably these geometers first attempted a direct solution. Only one text at our disposal supports this hypothesis: (1) Anal. Prior. 65 a 4–7. My analysis below in Chapter I shows that a mathematical meaning can be read from this somewhat obscure text only if it is interpreted as an allusion by Aristotle to those geometers who believe they are demonstrating, obviously in an absolute way, the proposition Elem. I 29, equivalent to the fifth postulate, but do not realize that in the process they are using lemmas which result themselves from the proposition to be demonstrated. Such a lemma would assert the uniqueness of the parallels, existence of which was shown in an absolute way in Elem. I 27. My conjecture and reconstruction afford a natural explanation for an inconsequence singular for Book I of the Elements, namely, the presence of the proposition Elem. I 31 in the purely Euclidean part of the book, in spite of the fact that the assertion merely repeats the absolute proposition Elem. I 27 without explicitly containing any Euclidean element.It is probable that the failure of these direct attempts led to an indirect approach to the problem through reductio ad absurdum of some hypothesis contrary to what was to become Postulate V or to some equivalent proposition. Numerous texts survive from which it is clear that geometers contemporary with Aristotle followed fairly far the consequences of an hypothesis contrary to the fifth postulate, obtaining important results which are partly identical with some theorems of Saccheri. Some of these texts attest first of all that what Saccheri called the Hypothesis of the Obtuse Angle had been stated in an independent and explicit way and that the fundamental result, identical with Prop. 14 of Saccheri's Euclides ab omni naevo vindicatus (1733), had been obtained, namely, that within Bolyai's Absolute Geometry this hypothesis leads to the remarkable formal contradiction that parallels intersect. This conclusion followed from two different formulations of the Obtuse Angle Hypothesis: (2) Anal. Prior. 66a 11–14, if the exterior angle (formed by a secant which intersects two parallel straight lines) is smaller than the interior angle (opposite and situated on the same side of the secant), and (3) 66a 14–15, if the sum of the angles in a triangle is greater than 2R. Finally, an item in (4) Ethica ad Eudemum 1222b 35–36 shows us that by investigating the Obtuse Angle Hypothesis, the Greek geometers also discovered the quadrilateral in which the sum of the angles is equal to 8R; this quadrilateral, which does not appear even in Saccheri's book, is the maximal quadrilateral of the Riemann geometry, a quadrilateral degenerated into a straight line closed upon itself (Chapter IV 20).Nowhere in the Corpus does the Hypothesis of the Acute Angle appear in an independent formulation. Nevertheless in (5) Anal. Poster. 90a 33–34 this Hypothesis is mentioned along with the other two: namely, Aristotle states that the essence of the triangle consists in the sum of its angles' being equal to, greater than or less than 2R (Chapter V 27). The formulation of the fifth postulate in the Elements allows greater probability to the conjecture of independent existence of the Acute Angle Hypothesis as well. Indeed, in its original formulation the fifth postulate is redundant, since it unnecessarily specifies in which of the half-planes (bounded by the secant) the intersection of the two straight lines occurs; this specification is itself a theorem. The Acute Angle Hypothesis must have been formulated not only symmetrically to (3) Anal. Prior. 66 a 14–15, that is, the sum of the angles of the triangle is less than 2R, as results from (5) Anal. Poster. 90 a 33–34, but also symmetrically to (2) Anal. Prior. 66 a 11–14. In the latter case the following final conclusion should have been reached in order to reduce to absurdity the Acute Angle Hypothesis: Two straight lines cut by a secant are incident if the sum of the interior angles (on the same side of the secant) is smaller than 2R, and the incidence occurs on that side of the secant where the sum of the angles is less than 2R. In the frame of the Acute Angle Hypothesis, this end conclusion is relevant only if this final specification (concerning the half-plane where the incidence occurs) is explicitly emphasised. According to my conjecture, it was precisely the practical impossibility of reaching this conclusion as a theorem of Absolute Geometry that later determined Euclid to transpose this decisive end conclusion from the Acute Angle Hypothesis, without changing its wording, and to include it among the postulates (Chapter II 13).A queer passage of Proklos (In primum Euclidis Elementorum, ed. Friedlein p. 368, 26–369, 1) in which the Acute Angle Hypothesis is presented in the form of a Zenonian paradox reinforces the conjecture that this hypothesis was studied independently by the ancient geometers (Chapter VI 33). Thus failure to solve the Problem of Parallels preceded not only the later Non-Euclidean geometry but also Euclidean geometry itself.The general undifferentiated Contra-Euclidean Hypothesis appears in the following form in all the other texts examined: The sum of the angles in the triangle is not equal to 2R. This hypothesis is nowhere qualified by Aristotle as being absurd or impossible: On the contrary, he takes it always as being just as much justified a priori as is the Euclidean theorem Elem. I 32 which contradicts it. For instance in (6) Anal. Poster. 93 a 33–35 Aristotle puts the problematical alternative: Which of the two propositions is right (or, which of the two constitutes the Logos, the raison d'être of the triangle), the one that states that the sum of the angles in the triangle is equal to 2R, or on the contrary, the one that states that the sum of the angles in the triangle is not equal to 2R (Chapter V 28)?In a number of texts the theorem Elem. I 32 itself and the general Contra-Euclidean Hypothesis are treated as being a sort of principle, and stress is laid on the idea that the logical consequences of each of these items invariantly preserve its specific (Euclidean or non-Euclidean) geometrical content [(7) 1187 a 35–38 (Chapter IV 18); (8) 1222 b 23–26 (Chapter IV 19); (9) 1187 b 1–2 (Chapter IV 18); (10) 1222 b 41–42 Chapter IV 21); (11) 1187 b 2–4 (Chapter IV 18)]; (12) Physica 200 a 29–30: If the sum of the angles in the triangle is not equal to 2R, then the principles of geometry cannot remain the same (Chapter V 25); (13) Metaph. 1052 a 6–7: It is impossible that the sum of the angles in the triangle be sometimes equal to 2R and sometimes not equal to 2R (Chapter V 24). Finally, the most important item of this sort is to be found in (14) De Caelo 281 b 5–7: If we accept as a starting hypothesis that it is impossible for the sum of the angles in the triangle to be equal to 2R, then the diagonal of the square is commensurable with its side (Chapter III).Another group of texts reveal Aristotle's attitude as regard these Contra-Euclidean theorems: (15) 1222 b 38–39 (Chapter IV 20); (16) 200 a 16–19 (Chapter VI 30); (17) 402 b 18–21 (Chapter VI 31); (18) 171 a 12–16 (Chapter VI 32); (19) 77 b 22–26 (Chapter V 26); (20) 101 a 15–17 (Chapter VI 31); (21) 76 b 39–77 a 3 (Chapter VI 31). These passages reveal Aristotle's conviction that these paradoxical Contra-Euclidean propositions (which cannot be annihilated by reductio ad absurdum) are nevertheless inacceptable as bad, probably because their graphical construction requires curved lines for representing the concept of straight lines.Finally, another group of texts show that Aristotle sensed in a way the necessity of adding to the foundations of Geometry a new postulate, from which the proposition Elem. I 32 should follow rigorously.

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Aram Frenkian zum Gedächtnis

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Vorgelegt von J. E. Hofmann     

知识产权信息管理的调控手段分析

知识产权信息管理是对知识产权制度运行中的信息资源的合理组织与有效利用,人们利用行政、法律、伦理等手段来协调解决信息技术应用及信息管理活动中出现的各类矛盾的方式,同样反映在了知识产权信息管理领域。因而本文重点从政策导向、法律制约、经济调整等角度,分析知识产权信息管理的诸多调控手段,以期推动实践中对知识产权信息管理机制的优化。     

燃煤发电与水泥生产联产技术可行性研究

本文基于解决我国以燃煤发电为主的电力工业的粉煤灰与SO2等酸性气体排放等难题的目的，从优化能源利用和洁净煤技术的角度出发，提出了燃煤发电与水泥生产联产技术。从原料代替、水泥煅烧工艺与掺杂热效应等方面和一系列实验证明了该联产技术的可行性，并就其前景作了分析。燃煤发电和水泥生产的合二为一，将会在我国的能源节约、环境保护与社会经济效益等方面产生深远而重大的意义，有效促进我国电力工业和水泥工业可持续发展。     

Y型明渠交汇水流分离区的数值分析

针对Y型明渠交汇口的水流特性，应用三维各向异性的雷诺应力模型，采用交错网格上的有限体积法离散控制方程，用SIMPLE算法求解压力-速度场。数值计算结果与物理模型试验结果吻合较好，并据此重点探讨了不同交汇角条件下交汇口分离区尺寸的变化规律，提出Y型交汇水流分离区的定义和分离区尺寸与汇流比的函数关系。     

Realism on the rocks: Novel success and James Hutton's theory of the earth

In this paper, I introduce a new historical case study into the scientific realism debate. During the late-eighteenth century, the Scottish natural philosopher James Hutton made two important successful novel predictions. The first concerned granitic veins intruding from granite masses into strata. The second concerned what geologists now term “angular unconformities”: older sections of strata overlain by younger sections, the two resting at different angles, the former typically more inclined than the latter. These predictions, I argue, are potentially problematic for selective scientific realism in that constituents of Hutton's theory that would not be considered even approximately true today played various roles in generating them. The aim here is not to provide a full philosophical analysis but to introduce the case into the debate by detailing the history and showing why, at least prima facie, it presents a problem for selective realism. First, I explicate Hutton's theory. I then give an account of Hutton's predictions and their confirmations. Next, I explain why these predictions are relevant to the realism debate. Finally, I consider which constituents of Hutton's theory are, according to current beliefs, true (or approximately true), which are not (even approximately) true, and which were responsible for these successes.     

“... in Christophorum Clavium de Contactu Linearum Apologia” Considerazioni attorno alla polemica fra Peletier e Clavio circa l'angolo di contatto (1579–1589)

Summary In this work 1 focus my attention upon the question of the angle of tangency in the XVI^th Century, especially in the polemic between J. Peletier and Chr. Clavius (1579–1589). The interest in the question favored deliberation about the theory of proportions, the principle of Eudoxus-Archimedes and the set of angles of tangency (this is a non-Archimedian set); there were problems about logical proofs and geometrical proofs.

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Memoria presentata da H. Freudenthal     

Out of the meridian: John Bird's equatorial sector and the new technology of astronomical measurement

When Thomas Hornsby commissioned John Bird to build a set of five major astronomical instruments for the new Radcliffe Observatory, Oxford, the order included an Equatorial Sector. This was an instrument of experimental design, intended to measure angles out of the meridian. Although in itself a transitional instrument, the Equatorial Sector's capacity for extra-meridional measurement, especially for the observation of comets, encouraged craftsmen to develop the design first into the Equatorial Circle, and then into the large equatorially mounted refracting telescope used in conjunction with micrometers. Although other Equatorial Sectors were made, Bird's instrument for Oxford is the only one that survives intact. The present study examines this unique artefact within the context of changing astronomical demands between the 1770s and the 1820s.     

刨煤机刨刀刨削煤层动力学模拟研究

刨刀刨削煤壁的过程中,切削角和刨刀的宽度影响刨刀的受力.为了减小刨刀的受力及冲击,根据刨煤机的实际工况,建立刨煤机刨削煤层的三维模型,并运用Hypermesh和LS-DYNA分析单个刨刀刨削煤层的受力状态.对不同切削角的刨刀进行仿真分析,结果表明:切削角为90°时,刨刀受力较大;切削角为70°时,刨刀受力较小.对不同宽度的刨刀进行仿真分析,结果表明:宽刨刀对煤层刨削区域影响大,刨削阻力较大,有利于刨削脆性煤层;窄刨刀对煤层的刨削区域影响小,刨削阻力小,有利于刨削粘性煤层.     

Crystal and molecular structure of 3, 3′-dibromobenzophenone

Résumé La structure du cristal de 3, 3-dibromobenzophénone a été définie par l'emploi de données obtenues par rayons X dans trois dimensions. Les distances et les angles de liaison ont été obtenus et l'on a trouvé que deux anneaux de phényle de la molécule ne sont pas dans le même plan, l'angle compris entre eux étant de 39,9°.     

Gauss's geodesy and the axiom of parallels

It is a myth that Gauss measured a certain large triangle specifically to determine its angle sum; he did so in order to link his triangulation of Hanover with contiguous ones. The sum of the angles differed from 180° by less than two thirds of a second; he is known to have mentioned in conversation that this constituted an approximate verification of the axiom of parallels (which he regarded as an empirical matter because his studies of hyperbolic trigonometry had led him to recognize the possibility of logical alternatives to Kant and Euclid). However, he never doubted Euclidean geometry in his geodetic work. On the contrary, he continually used 180° angle sums as a powerful check for observational errors, which helped him to achieve standards of precision equivalent to today's. Nor did he ever plan an empirical investigation of the geometrical structure of space.     

Fish with a Different Angle: The Fresh-Water Fishes of Great Britain by Mrs Sarah Bowdich (1791–1856)

Since first appearance, reviews and accounts of The Fresh-Water Fishes of Great Britain (1828–1838) have been surprisingly few. All agree that this rare work is remarkable for its illustrations. Its importance as a whole in the history of ichthyology, however, is largely unknown, or ignored. This article therefore constitutes the first study of the textual and contextual significance of The Fresh-Water Fishes of Great Britain. By examining in chronological order where, and by whom, the work was first reviewed and referenced until the 1860s, the extraordinary contributions that its author, Sarah Bowdich, made to ichthyology at the forefront of the field in the late 1820s can better be appreciated. Indeed, this multiple evidence demonstrates Sarah Bowdich's merits as an ichthyologist of the first order, and as the first woman ichthyologist. But establishing the significance of The Fresh-Water Fishes of Great Britain for the history of ichthyology then raises a further question. Why has it and its author been so ignored or forgotten? By returning for answers to the fields of ichthyology already considered, the article proposes that Sarah Bowdich's different angles on fish offer lines of investigation that are still important for the field today.