bluuebunny/crossref_metadata_2025 huggingface dataset:
ON THE GENERALIZED SLOPE-DEFLECTION EQUATIONS
Authors: PAN CHIA-CHENG  ,   中央燃料工业部水力发电总局设计局
Published: November 2020

This paper investigates the general and complete form of slope-deflection equations used in structural analysis. The word "complete" indicates that all the possible deformations (deflections and rotations) and all the strain energies (due to shear, direct stress and flexure) are included in the equations. The definitions, numbers, and relations of member constants are then discussed and the general equations for computing these constants are given. By neglecting the factors of minor importance, the general form is reduced to the usual slope-deflection equations. Some special forms of such equations which are useful in certain practical problems are also discussed briefly, such as the slope-deflection equations including the effect of direct stress on flexure and the slope-deflection equations of semi-rigid frames. Slope deflection equations for trussed bents are also presented.
EFFECT OF MICRO-STRUCTURE OF THE SPECIMEN ON THE SPECTROCHEMICAL ANALYSIS OF ALLOY STEELS
Authors: HO I-DJEN  , CHANG KUNG-SOO  ,   中国科学院金属研究所
Published: November 2020

In the spectrochemical analysis of high speed steels with a small current activated a.c. arc (after Aбрамсон), the results of analysis were found to be affected by different previous heat-treatments given to the steel samples. To study this effect we selected 10 chromium steel samples of different carbon content. Spectrochemical analysis of these samples under different procedures of heat treatment shows that with an a.c. arc (5 amp.) the results of analysis of Cr for annealed and for hardened samples of the same steel are different and the difference increases with the increase of carbon content. We are inclined to think that in a low energy light source, the evaporation and the excitation of the alloying elements vary according to the existing form of carbon and this directly affects the results of spectrochemical analysis. The magnitude of this effect is different for different alloying elements, it is considerable in the case of Cr but is inappreciable in the case of Mn and Si.How to eliminate the effect of micro-structure on spectrochemical analysis was also investigated. It was found that with a low energy light source, the effect can not be eliminated by increasing the time of pre-arcing. However, this effect is considerably reduced by using a spark source or an a.c. arc source of large current.
A METHOD FOR SOLVING ELECTRIC NETWORK
Authors: TSOU JUI  ,   华中工学院
Published: November 2020

In this paper a method for solving electric network is suggested. By this method, the solution of the network may be found conveniently without solving simultaneous equations.This paper consists of two parts. The first part deals with the method for solving the general linear network. The procedure of which is, firstly, to replace the e.m.fs. in the network by an equivalent source of currents; secondly, to eliminate the joints of the network one by one until the network transforms into an equivalent branch for finding the potential difference between the terminals of this branch; thirdly, to restore the equivalent branch to original network for finding the potentials of all joints of the network; finally, we can calculate the currents of the branches of the network easily. The second part deals with the special method for solving the linear network which contains only one e.m.f. The difference between this method and the former one is that the proceeding of restoring the equivalent branch to original network in this method may be omitted. In order to omit this proceeding, it is necessary to assume a certain amount of current source on every joint of the network before the transformation of the network. Therefore, when the network transforms into an equivalent branch, we may find the potentials of all joints of a network which contains only one e.m.f.
ON THE PARAMAGNETIC ANISOTROPY OF SINGLE CRYSTALS OF CHROME ALUMS
Authors: HSIANC JEN-SHENG  ,   中国科学院应用物理研究所
Published: November 2020

The existence of anisotropy in paramagnetic cubic crystals has never been observed and it was only vaguely conjectured by Schlapp and Penney in 1932 for chrome alums. In this paper, a calculation based on P. R. Weiss's theory (1948) shows that the paramagnetic anisotropy does exist in the single crystals of chrome alums. Percentage differences (γ ) between the susceptibility along direction (χ) and that along direction (χ) in KCr alum single crystal at room temperature are given for several values of magnetic field. It is pointed out that the ordinary concept of principal susceptibilities along respectively three mutually perpendicular magnetic axes is no longer applicable to describe the paramagnetic anisotropy of the cubic crystals of chrome alums.
ORDERING AND VACANCY DIFFUSION IN AuCu3
Authors: SZE SHIH-YUAN  ,   南京大学
Published: November 2020

It is shown that the probability of an disordered atom to be ordered in unit time can be correlated to the coefficient of diffusion by the relation a=9/4 d/a2 (m2/m1)1/2 (△S2-△S1)/k(Tc/T-1) where a=the probability of ordering, D=the coefficient of diffusion, a =the lattice constant of AuCu3,m1 and m2 the mass of an atom of gold and copper respectively,△S1, △S2 being respectively the entropy change when a gold and a copper atom jumps to a neighboring vacancy, k, the Boltzmann constant, Tc, T, the critical temperature and the absolute temperature under consideration.This relation has been verified with experimental data. With experimental value of a and D0, it gives an activation energy of 2.10 eV which is equal to the activation energy of self-diffusion of copper within the limits of experimental accuracy. This expression explains the existance of a temperature at which the rate of ordering is maximum both qualitatively and quantitatively.
APPROXIMATE SOLUTION OF THE MILNE PROBLEM FOR AN INFINITE BLACK CYLINDER BY THE METHOD OF SPHERICAL HARMONICS
Authors: HUANG TSO-CHIA  ,   中国科学院物理研究所
Published: November 2020

The neutron distribution in an infinite medium around an infinitely long black cylinder is investigated. The medium satisfies the conditions typical for Milne's problems. By the method of expanding the distribution function in terms of the spherical harmonics, we transform the Boltzmann transport equation for our case [eq. (1)] into an infinite set of ordinary differential equations for the infinite number of coefficients of expansion feq. (10)]. We obtain approximate solutions-P1, P3, and P5 approximations [expressions (21), (25)and (26)] by retaining only the first two, six and twelve terms of the expansion.Numerical results of the calculation of the extrapolated length λ for various values of aare shown in Table 2 and plotted in the figure. Both λ and a are expressed in units of l-themean free path of neutrons in the medium.For comparison, we plotted also the curve given by Davison (curve D in our figure). His curve is based on his approximate solutions of the Peierls integral equation for the two limit cases a?1 and a?1 and an interpolation for intermediate values of a according to the result of P3 approximation. It appears from the figure that for large a the result of P5 approximation is already very near to the curve D and that it seems more reasonable to lower a little the part of the curve D near a=1 in order to conform better with the tendency of the curve P5 (as, e.g., shown by the dotted line).In the Appendix, some relations concerning spherical harmonics needed in the text are obtained.
AN INVESTIGATION OF Ag-Au-Zn ALLOYS WITH 50 AT. % Zn
Authors: LIU YI-HUAN  , HSU CHEK-CHIA  ,   中国科学院应用物理研究所
Published: November 2020

A β″ superlattice structure, with the ideal stoichiometrical formula AgAuZn2 and isoinorphous with that of Heusler alloys, has been found existing over a quite wide range of composition. It is, in fact, a superstructure of the β′ ordered structure. Its formation is accompanied by a sudden lattice contraction. The effect of gradual substitution of Ag by An on the atomic distribution has been stndied systematically. It is shown that the Au atoms introduced simply replace the Ag atoms more or less in a random manner, the positions of Zn atoms not being affected. Tho decrease of the degree of order as deviating from the stoichiometrical formula is not merely due to the deviation from the ideal chemical composition; some disordering among the Ag and Au atoms also occurs. High temperature investigation of Ag-rieh alloys shows that the temperature of β′-β transformation increases with Au content and that the β-phase structure exists only at high temperatures. The presence of even a minute amount of Au stablizes the β′ structure obtained by quenching very remarkably. On the other hand, the β′ structure of Au-rich alloys persists from room temperature probably to the melting point.
THE ELECTRIC MULTIPOLE INTERNAL CONVERSION INDUCED BY NEUTRON TRANSITION
Authors: TZU HUNG-YUAN  ,   中国科学院物理研究所
Published: November 2020

The effect of the anomalous magnetic moment of the nucleon on the value of the internal conversion coefficient is investigated.The parts played by the sealer and tho longitudinal photons in the process of the internal conversion are first discussed. The retarded interaction between the charged particles with anomalous magnetic moment is derived by the correspondence method. The results obtained is then verified by the quantum electrodynamical treatment. The retarded interaction thus obtained is then applied to the calculation of the internal conversion coefficient. It turns out, that the anomalous magnetic moment of the nucleon has negligible influence upon the coefficient of the magnetic conversion and the coefficient of the electric conversion induced by the proton transition. However, the anomalous magnetic moment of the nucleon does cause considerable modification of the coefficient of the electric conversion induced by tho neutron transition, contrary io the conclusion arrived a,t by various authors. The problem of the gauge transformation is discussed and the errors contained in the treatment given by these authors are pointed out.
FREE ENERGY OF A SOLID SOLUTION ON A FACE-CENTRED CUBIC LATTICE
Authors: TIN HOU-CIIAKG  , TSIAO TUNG-KIANG  , CHANG TSUNG-SUI  ,   (1)江苏师范学院; (2)中国科学院数学研究所
Published: November 2020

This paper applies Kirkwood's method for calculating the configurational free energy E of a solid solution to a solid solution AB3 inhabiting a face-centred cubic lattice. In this method, the free energy F is expressed as a series in (kT)A-1, and our calculation goes as far as the coefficient of (kT)-4. If the order of the solid solution is denoted by S and the free energy on neglecting 0(kT)-n by Fn, the relation between Fn and S are found to depend on n in a marked manner. In particular, F3 and F5, have always a minimum at S=0, implying no superlattice may exist. The foregoing is actually nothing but an indication of the slow convergence for the expansion of F in (kT)-1. On expressing F as a series in η≡exp{-(VAA+VBB-2VAB)/kT}-1 where VAA, VBB and VAB are interaction energies between AA, BB and AB pairs of nearest neighbours and denoting by Fn′ the free energy on neglecting O(ηn) , we find that F2′ and F3′ do not give us any superlattice, but F4′, F5′ do. In fact, from F4′, F5′, we get a sudden change of S accompanied by a latent heat, just as in the earlier theories. F4′, F5′ behave similarly, so we may hope they approximate the actual free energy.
CONFIGURATIONAL PARTITION FUNCTION OF BINARY SOLID SOLUTIONS
Authors: WANG TEH-MOU  , HSU HOU-GHANG  , CHANG TSUNG-SUI  ,   (1)贵阳师范学院; (2)延边大学师范学院; (3)中国科学院数学研究所
Published: November 2020

The present paper continues an earlier investigation of the application of Meyer's theory of a gas mixture of two components to a solid solution AB inhabiting a lattice of the type AB by considering the A. atoms inhabiting the two different sublattices as forming two different components. It is proved that the different irreducible cluster integrals are linear functions (and hence the free energy of the solid solution) of coordination numbers of the type ∑λabλa′b′λ……, where a, a′,…, b,b′… are different sites on the two sublattices (say a and β sublattices) and λab is a neighbour matrix defined by λab=1 when a, b are nearest neighbours =0 if otherwise,the product in (1) is irreducible with respect to the suffices (i. e. not divisible into parts with one or no suffice in common) and the summation is taken over all positions of a, a′,…,b b′,…, (a, a′, a",… as well as b, b′… being always different). Galling such coordination numbers as z1,z2,…and writing the free energy F of the solid solution as f0+z1f1, z2f2+…,(2) we point out that these Fi may be calculated from the free energies of the same solution, but now with the sites falling into groups each of which contains a small number of sites and does not contain sites which are neighbours of sites belonging to a different group. Since F of these solid solutions may be found easily (without approximations), we succeed in getting the required free energy F. Of course, this is an approximate method of calculating F, since we can not find the various Fi at one stroke.It is finally pointed out that such a method allows extension to lattices of different structure, to components more than two, to include interactions between next nearest neighbours, etc.
ON THE REFLECTION ON TRANSPARENT PHOTOCATHODES
Authors: ZS. NARAY  , M. TOTH  ,   中央物理研究所宇宙线研究室,布达佩斯,匈牙利
Published: November 2020

For the investigation of the reflection on transparent photocathodes we worked out a comparative method. By this method the absolute values of the common reflection coefficient of photocathode and glass envelope could be determined. Investigating a generally used type of photomultiplier (type RCA-5819) we found it to show a comparatively high reflection-50 per cent-in the maximum of sensitivity.
A PHASE DIAGRAM OF THE ALLOYS OF THE TERNARY SYSTEM OF Ag-Sb-Sn
Authors: C. S. CHENG  ,   东北人民大学
Published: November 2020

A phase diagram of the alloys of the ternary system of Ag-Sb-Sn was constructed on the basis of the data obtained by X-ray analysis and metal-lographic examinations.The phase diagram obtained consists of six single-phase regions (namely a,β,γ,β′, Sn and Sb regions), seven two-phase regions(namely a+β,β+γ,γ+β′,γ+Sn,γ+Sb,β′+Sn,β′+Sb regions) and two three-phase regions(namely γ+β′+Sn,γ+β′+Sb regions). No new phase was observed in these alloys of the ternary system.
A NOTE ON THE ERGODIC THEOREM FOR QUANTIZED SYSTEMS
Authors: CHANG TSUNG-SUI  ,   中国科学院数学研究所
Published: November 2020

In a paper by Klein, it is pointed out that for the quantum mechanical ergodic theorem (time average = average over states) to be valid, all integrals of motion R must satisfy the condition ∑ρ"(α′ρ"|R|β′ρ")=const δα′β′ (1) where α′, β′, γ, … refer to the assembly under question and α", β",…, ρ" ,… refer to the surrounding with which our assembly is in equilibrium. In this short note, it is pointed out that the argument of Klein is doubtful at one point and a slightly different approach is given. In this approach, it is shown that (1) is actually sufficient, but only after introducing an additional assumption that the different states of the surroundings have equal probabilities, and that in general, a stronger condition such as (α′ρ″|R|β′θ″)=const δα′β′δρ″θ″ (2) is needed. Cases with integrals of motion is also considered. We consider first an isolated system, write the wave function as (α1α2>, where α1 represents a set of commuting integrals of motion and α2 a set of observables not containing integrals of motion and introduce the assumption that for any integral of motion R, the matrix 1α′2Rα1"α2"> representing it is of the form φ(α′1α1")δ(α′2α2"). (3) Under such conditions, we prove that if the initial state of our system is an eigenstate of α1 corresponding to the eigenvalue α10, then the average of an observable F over time is given by ∑α210α2|F|α10α2>/∑α210α2|1|α10α2>, a result which is clearly to be expected. Extension to systems interacting with external surroundings is easily made.
GROWTH OF NaCl CRYSTALS FROM SUBLIMED VAPOR
Authors: CHANG YUAN-LUNG  ,   中国科学院地质研究所
Published: November 2020

By sublimation of NaCl crystals of high purity in vacuum at a temperature near its melting point single NaCl crystals of macroscopic size were grown at zones of somewhat lower temperatures. Oriented overgrowths up to 1 mm thick were obtained over the whole cleavage faces of the crystals, but the deposition was muchmore effective on the faees normal to the temperature gradient.The influence of zonal temperature differences and the geometric form of the substrate upon the size and orientation of the crystals have been investigated. The relative importance of faces observed was found of the following sequence: 100> 111>120>122>110. of these the form 122 has not been reported for NaCl crystals growing from the solution. But there is ample evidence from the present experiment that the dominance of 111 over 120 may not be as certain as obsreved for the crystals prepared from solution.In accord with the theory generally held, initial deposition was found to take place statistically more often at the corners of cube faces than elsewhere. New patterns of interpenetration growth and surface structures have been observed and there are features indicating layer growth and screw dislocation.Preliminary experiment was also made on evaporation of a cylindrical NaCl crystal resulting in the exposition of the faces (100) and (120).
THE PROPERTIES, PRODUCTION AND DECAY OF STRANGE PARTICLE
Authors: HO AN-SHING  ,   原子能研究所
Published: November 2020

The cloud-chamber has a volume 30×30×10 cm3 in a maguetic field of 6200 gauss, which is operated at a 3185m mountain altitude. In a set of 30000 pairs of photographs taken, 105 events of the decay of neutral V particles and 21 of the decay of charged particles wore observed. It is seen that 16 events have been classified as due to the decay of ∧0 particles, 26 as due to the decay of θ10 particles, one as decay of a θ20 particle and 62 as nonclassified. We have studied the following properties of the ∧0 and θ0 particles, the results of which are summamed as follows: 1) Q values Q(Λ0)=(36.2±2.5)Mev, Q(θ10)=(233±11)Mev; 2)mean lifotimes τ(Λ0)=(3.19-0.92+2.42)×10-10sec,τ(θ10)=(1.14-0.27+0.49)×10-10sec; 3) The Momentum distributions found for ∧0 and θ0 particles have no appreciable difference with earlier results;4) N(∧0)/N(θ10)=0.51±0.22 (corrected number in lead);5) The angular distributions of the decay products of the ∧0 and θ0 particles in the rest system have no marked asymmetry;6) The lifetime of one θ20 particle is estimated to be :10-9 sec. in the rest system. The decay mode of this θ20 particle is probably θ20→π-+π++π0 or θ20→π±+μ?+ν.
THE RADIATIVE CAPTURE OF μ-MESON BY PROTON
Authors: DAI Y. B.  , SAN D. C.  , HO T. H.  , TZU H. Y.  ,   数学研究所和原子能研究所
Published: November 2020

The radiative capture of μ-meson by proton is treated by using the renor-malized universal Fermi interaction of V-A type and Zeldowich's theory of μ mesic hydrogen. Contrary to the result of Lee, Huang and Yang, it is found that, if the effect of the strong interaction is neglected, then it is impossible for photon being emitted during the capture. The influence of the strong interaction consists of two respects, namely: the effect of the magnetic moment of the nucleon and the renormalization effect on the universal Fermi weak interaction. The effect of the anomalous magnetic moment is negligible. However, the contribution of proton to the emission of photon is not at all small in comparison with that of the μ-meson duo to the renormalization effect on the universal Fermi weak interaction. As a result, the photons emitted are no longer 100% right hand polarized. It is estimated, that only 80% of the photons has a spin parallel to its momentum. The radiative capture rate of the μ-meson by proton is 1/(1.6×105) of thetotal capture rate.
AUTOMATIC DEVICE FOR TYPE ИСП-22 SPECTROGRAPH
Authors:   中国科学院冶金陶瓷研究所
Published: November 2020

In this article, it briefly introduces that by means of the three electro time-relays to control the arc-burn period, the pre-burn period and the moving distance of the photographic box, it simplifies the procedure of the work, shortens the required time and greatly raises the efficiency of the work concerned.
THE BRANCHING RATIO OF THE DECAY OF THE K+-MESON
Authors: LEE WEN-TZU  , SAN DING-CHANG  , HO TSU-HSIU  , TZU HUNG-YUAN  ,   中国科学院原子能研究所
Published: November 2020

The branching ratio of the following three modes of K+-meaon decay K+→μ++π0+ν K+→e++π0+ν K+→μ++ν is calculated by using the theory of the universal Fermi weak interaction proposed by Feymann and others. Perturbation method with cut-off is used. The ratio obtained is 1:1.5:12, which is in fair agreement with the experimental value 1:1:15. It is shown, other conbinations of Fermi interactions can not give result in agreement with experiment.
A NEW METHOD OF ZONE MELTING FOR REFINING SUPER-PURITY GALLIUM
Authors: LIU MIN-CHIH  ,   中国科学院物理研究所
Published: November 2020

This paper describes a new method for refining super-pnrity Ga (99.9999%). By means of this method it provides multiple zone on one side of the helix of plastic tubing in which the material to be refine1 is filled. Thus when the helix rotates, the melting zones travel endlessly throughout the specimen. The efficieney of this arrangement is thought to be higher than that of the conventional one.
THE CONFIGURATIONAL PARTITION FUNCTIONS OF SOLID SOLUTIONS
Authors: CHANG TSUNQ-SUI  ,   中国科学院数学研究所
Published: November 2020

This short papper applies a method for studying the configurational partition function of regular solutions developed by Wang, Hsu and the author to a number of special cases. In sucb concrete calculations it is seen that the method is applicable to almcst every type of solid solutions. In fact, its applicability is independent of the type of lattice which atoms of the solution inhabit, of the existence of the long distance order, of the existence of interactions between atoms more distant than nearest neighbours, and of the number of components in the solution. Since the method is actually an expansion of the configurational free energy in terms of certain coordination numbers of the lattice, the results of the calculations after ignoring the higher coordination numbers become closed expressions in terms of the Boltzmann factors and thus avoids expansions in kT or in (kT)-1. Needless to say, expansion of the results obtained here in (kT)-1 gives results identical with those obtained by Kirkwocd's method. Next we discuss quasi-chemical formulas based on the above method. We point out that if we neglect all the coordination numbers except the lowest, we obtain the usual quasichemical formula, quite independently of the number of components in the solution, (A corresponding combinatory formula is derived.) On including higher coordination numbers, we get natural extensions of the quasi-chemical formula. Thus for a binary solid solution on a face centred cubic system, the quasi-chemical formula after including the next higher coordination number becomes In the above, NθA, NθB denote the numbers of A, B atoms, X′AA, X′AB,…,X",… are numbers determined by (2), (3), (4), and their substitution into the right hand sides of (1) gives the numbers XAA XAB, XBB of AA, AB, BB pairs of nearest neighbours. It may be noted that X′ may be negative and they do not bear any direct physical significance.It is also pointed out that instead of considering the numbers of pairs of nearest neighbours, we may consider directly the numbers of pairs of triplets (ie. 3 atoms forming mutually nearest neighbours) and write down by analogy (to the usual quasi-chemical formula) new quasi-chemical equations for the different numbers of triplets. (From this, a combinatory formula is easily derived). It is shown that such a theory differs from (1)-(4) given above.
ANGTJLAR DISTRIBUTION OF THE DECAY PRODUCTS OF HYPERONS
Authors: CHEN  , J. M.  , HO  , T.H.  , SAN  , D. C.  , TZU  , H. Y.  ,   中国科学院原子能研究所
Published: November 2020

By assuming various forms of interaction Hamiltonian the angular distribution of the decay products of spin 1/2 particle obeying the Dirac equation and that of spin 3/2 particle obeying Rarita-Schwinger equation are calculated. The ratio of the strength of parity conserving and the parity non- conserving interaction on the one hand and the asymmetry parameter α on the other hand is discussed. It is pointed out, that if the vector and pseudo-vector coupling in the universal Fermi weak interaction proposed by Feynman and Gell-Mann are exactly equal to each other, then this theory gives an asymmetry parameter α of Λ particle decay, which is consistent with the experimental result. If the ratio of the square of these two coupling constants is 1:1.55 as suggested by β-decay experiments, then the asymmetry parameter derived from this theory is -0.97, which is already on the margin of the experimental data. The angular distribution of the decay products of spin 3/2 particle obeying the Rarita-Schwinger wave equation cannot be made agree with the experimental result of the ∧ particle decay, a conclusion, which was first pointed out by Lee and Yang by using general arguments.
Two-stage Decision-Making Approach to Survey the Excessive Usage of Smart Technologies
Authors: Borissova Daniela , Dimitrova Zornitsa , Garvanova Magdalena , Garvanov Ivan , Cvetkova Petya , Dimitrov Vasil , Pandulis Andrea
Published: November 2020

The article discusses the decision-making problems associated with smart technologies and their usage. For the goal, a two-stage decision-making approach is proposed to survey if smart technologies are used excessively. The first part is focused on composing a survey based on a questionnaire. This investigation should cover a wide range of users of different ages. To make a suitable questionnaire to conduct such a survey a set of predefined questions is to be evaluated. The evaluation should be based on a well-defined structured technique able to motivate rational decision-making. The evaluation of the given number of questions is done by using of well-known technique that decomposes the decision problem into a hierarchy of more sub-problems (analytic hierarchy process) developed by Saaty. The questions are ranked with respect to four evaluation criteria. From the obtained ranking list of questions, the first three questions are selected to compose a questionnaire for quick conduction of survey for investigation of the impact of excessive use of smart technologies. Keywords: Composing of surveys, decision-making, AHP, smart technologies.
Structural basis for PRC2 decoding of active histone methylation marks H3K36me2/3
Authors: Finogenova Ksenia , Bonnet Jacques , Poepsel Simon , Schäfer Ingmar B , Finkl Katja , Schmid Katharina , Litz Claudia , Strauss Mike , Benda Christian , Müller Jürg
Published: November 2020

Repression of genes by Polycomb requires that PRC2 modifies their chromatin by trimethylating lysine 27 on histone H3 (H3K27me3). At transcriptionally active genes, di- and tri-methylated H3K36 inhibit PRC2. Here, the cryo-EM structure of PRC2 on dinucleosomes reveals how binding of its catalytic subunit EZH2 to nucleosomal DNA orients the H3 N-terminus via an extended network of interactions to place H3K27 into the active site. Unmodified H3K36 occupies a critical position in the EZH2-DNA interface. Mutation of H3K36 to arginine or alanine inhibits H3K27 methylation by PRC2 on nucleosomesin vitro. Accordingly,DrosophilaH3K36A and H3K36R mutants show reduced levels of H3K27me3 and defective Polycomb repression of HOX genes. The relay of interactions between EZH2, the nucleosomal DNA and the H3 N-terminus therefore creates the geometry that permits allosteric inhibition of PRC2 by methylated H3K36 in transcriptionally active chromatin.
Journal policies and editors’ opinions on peer review
Authors: Hamilton Daniel G , Fraser Hannah , Hoekstra Rink , Fidler Fiona
Published: November 2020

Peer review practices differ substantially between journals and disciplines. This study presents the results of a survey of 322 editors of journals in ecology, economics, medicine, physics and psychology. We found that 49% of the journals surveyed checked all manuscripts for plagiarism, that 61% allowed authors to recommend both for and against specific reviewers, and that less than 6% used a form of open peer review. Most journals did not have an official policy on altering reports from reviewers, but 91% of editors identified at least one situation in which it was appropriate for an editor to alter a report. Editors were also asked for their views on five issues related to publication ethics. A majority expressed support for co-reviewing, reviewers requesting access to data, reviewers recommending citations to their work, editors publishing in their own journals, and replication studies. Our results provide a window into what is largely an opaque aspect of the scientific process. We hope the findings will inform the debate about the role and transparency of peer review in scholarly publishing.
Enantioselective Total Synthesis of Pentacyclic Proaporphine Alkaloid (−)‐Misramine
Authors: Pu Liu‐Yang , Yang Fan , Chen Ji‐Qiang , Xiong Ying , Xie Jian‐Hua , Zhou Qi‐Lin
Published: November 2020

An enantioselective total synthesis of pentacyclic proaporphine alkaloid (−)‐misramine has been achieved. The synthetic route features a Pictet‐Spengler cyclization to construct the fused B and C rings and a sequence of Baeyer‐Villiger oxidation, Pinnick oxidation, and pinacol‐type cyclization to install the α‐hydroxy ketal moiety. The absolute configuration of the pentacyclic framework was elucidated by X‐ray single‐crystal analyses of (−)‐11‐demethoxymisramine.

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Recent Progress of Protein‐Based Data Storage and Neuromorphic Devices
Authors: Wang Junjie , Qian Fangsheng , Huang Shenming , Lv Ziyu , Wang Yan , Xing Xuechao , Chen Meng , Han Su-Ting , Zhou Ye
Published: November 2020

By virtue of energy efficiency, high speed, and parallelism, brain‐inspired neuromorphic computing is a promising technology to overcome the von Neumann bottleneck and capable of processing massive sophisticated tasks in the background of big data. The abilities of perceiving and reacting to events in artificial neuromorphic systems allow us to build the communicative electronic–biological interfaces to get closer to electronic life. Protein materials offer great application potentials in such a system due to their sustainability, low cost, controllable hierarchical structure, intrinsic biocompatibility, and biodegradability. Herein, a timely review of the development of protein‐based memories for data storage and neuromorphic computing is provided. Proteins’ unique mechanical, electronic, optical properties, and their broad applications are discussed. Then, the progress of protein‐based two‐terminal memristor and three‐terminal transistor‐type memory is reviewed, and their applications for data storage, logic circuit, and neuromorphic computing are introduced. Finally, the major challenges and outlook toward the future developing directions of protein‐based computing systems are pointed out.
Estimation of differential occupational risk of COVID‐19 by comparing risk factors with case data by occupational group
Authors: Zhang Michael
Published: November 2020

Background

The disease burden of coronavirus disease 2019 (COVID‐19) is not uniform across occupations. Although healthcare workers are well‐known to be at increased risk, data for other occupations are lacking. In lieu of this, models have been used to forecast occupational risk using various predictors, but no model heretofore has used data from actual case numbers. This study assesses the differential risk of COVID‐19 by occupation using predictors from the Occupational Information Network (O*NET) database and correlating them with case counts published by the Washington State Department of Health to identify workers in individual occupations at highest risk of COVID‐19 infection.

Methods

The O*NET database was screened for potential predictors of differential COVID‐19 risk by occupation. Case counts delineated by occupational group were obtained from public sources. Prevalence by occupation was estimated and correlated with O*NET data to build a regression model to predict individual occupations at greatest risk.

Results

Two variables correlate with case prevalence: disease exposure (r = 0.66;p = 0.001) and physical proximity (r = 0.64;p = 0.002), and predict 47.5% of prevalence variance (p = 0.003) on multiple linear regression analysis. The highest risk occupations are in healthcare, particularly dental, but many nonhealthcare occupations are also vulnerable.

Conclusions

Models can be used to identify workers vulnerable to COVID‐19, but predictions are tempered by methodological limitations. Comprehensive data across many states must be collected to adequately guide implementation of occupation‐specific interventions in the battle against COVID‐19.
Rational Construction of Borromean Linked Crystalline Organic Polymers
Authors: Guo Xiuxiu , Lin En , Gao Jia , Mao Tianhui , Yan Dong , Cheng Peng , Ma Shengqian , Chen Yao , Zhang Zhenjie
Published: November 2020

Attributed to the unique topological complexity and elegant beauty, Borromean systems are attracting intense attention. However, at present, the construction of Borromean linked organic polymers remains a challenge. To address this formidable challenge, we developed a supramolecular‐synthon‐driven approach to fabricate Borromean linked organic polymer. The solvothermal condensation reaction of a judiciously selected trigonal pyramidal building block, 1,3,5‐Tris(4‐aminophenyl)adamantane, with linear dialdehyde building blocks allowed the construction of two rare covalent organic frameworks (COFs) with high crystallinity and robustness. Structure refinement unveiled the successful formation of entangled 2D→2D Borromean arrayed structures. Both the two COFs were of microporosity and thus demonstrated the potentials for gas separation. The successful synthesis of the first two Borromean linked organic polymers paves the avenue to expand the supramolecular‐synthon‐driven approach to other building blocks and topologies, and broadens the family and scope of COFs.
Isolierung und Reaktivität eines s‐Block‐Metall‐Antiaromaten
Authors: Roy Dipak Kumar , Tröster Tobias , Fantuzzi Felipe , Dewhurst Rian D. , Lenczyk Carsten , Radacki Krzysztof , Pranckevicius Conor , Engels Bernd , Braunschweig Holger
Published: November 2020

Das Konzept der Aromatizität und der Antiaromatizität ist seit langem bekannt, und zahlreiche Belege für dieses Phänomen wurden durch Moleküle, welche auf Elementen des p‐, d‐ und f‐Blocks des Periodensystems der Elemente (PSE) basieren, geliefert. Aufgrund der begrenzten Varianz des Oxidationszustandes von s‐Block‐Metallen konnten diese bisher nicht mit komplexen π‐Bindungssystemen interagieren. Daher gibt es keine bzw. nur schlecht beschriebene Beispiele für antiaromatische Systeme mit s‐Block‐Metallen. Durch die Verwendung von spektroskopischen, strukturanalytischen und quantenchemischen Methoden konnte eine heterocyclische Verbindung hergestellt und charakterisiert werden, welche das Erdalkalimetall Beryllium enthält und signifikante Antiaromatizität aufweist. Weiterhin beschreiben wir die Reaktivität gegenüber Lewis‐Basen und die chemische Reduktion dieser Verbindung.
Single‐Entity Electrocatalysis of Individual “Picked‐and‐Dropped” Co3O4 Nanoparticles on the Tip of a Carbon Nanoelectrode
Authors: Quast Thomas , Aiyappa Harshitha Barike , Saddeler Sascha , Wilde Patrick , Chen Yen‐Ting , Schulz Stephan , Schuhmann Wolfgang
Published: November 2020

Nano‐electrochemical tools to assess individual catalyst entities are critical to comprehend single‐entity measurements. The intrinsic electrocatalytic activity of an individual well‐defined Co3O4 nanoparticle supported on a carbon‐based nanoelectrode is determined by employing an efficient SEM‐controlled robotic technique for picking and placing a single catalyst particle onto a modified carbon nanoelectrode surface. The stable nanoassembly is microscopically investigated and subsequently electrochemically characterized. The hexagonal‐shaped Co3O4 nanoparticles demonstrate size‐dependent electrochemical activity and exhibit very high catalytic activity with a current density of up to 11.5 A cm−2 at 1.92 V (vs. RHE), and a turnover frequency of 532±100 s−1 at 1.92 V (vs. RHE) towards catalyzing the oxygen evolution reaction.
Isolation and Reactivity of an Antiaromatic s‐Block Metal Compound
Authors: Roy Dipak Kumar , Tröster Tobias , Fantuzzi Felipe , Dewhurst Rian D. , Lenczyk Carsten , Radacki Krzysztof , Pranckevicius Conor , Engels Bernd , Braunschweig Holger
Published: November 2020

The concepts of aromaticity and antiaromaticity have a long history, and countless demonstrations of these phenomena have been made with molecules based on elements from the p, d, and f blocks of the periodic table. In contrast, the limited oxidation‐state flexibility of the s‐block metals has long stood in the way of their participation in sophisticated π‐bonding arrangements, and truly antiaromatic systems containing s‐block metals are altogether absent or remain poorly defined. Using spectroscopic, structural, and computational techniques, we present herein the synthesis and authentication of a heterocyclic compound containing the alkaline earth metal beryllium that exhibits significant antiaromaticity, and detail its chemical reduction and Lewis‐base‐coordination chemistry.
Decision‐making impairments under ambiguous and risky situations in patients with prefrontal tumor: A neuropsychological study
Authors: Wang Yuyang , Wang Xukou , Wang Kai , Zhao Bing , Chen Xingui
Published: November 2020

Introduction

The neural mechanism underlying decision‐making, which is an important component of executive function, is complex and not fully understood. Few studies have directly investigated the two types of decision‐making functions – under ambiguity and under risk – in patients with brain tumors in different brain regions.

Methods

Participants were classified into the ventral prefrontal cortex tumor group (VPFC, n = 27), the dorsolateral prefrontal cortex tumor group (DLPFC, n = 29), and matched healthy controls (HCs, n = 32). All participants were given a battery of neuropsychological tests, and they then performed the Iowa Gambling Task (IGT) and the Game of Dice Task (GDT) to assess their decision‐making under ambiguity and under risk, respectively.

Results

The two patient groups performed significantly worse on attention, memory, information processing, and executive function. Additionally, patients in the DLPFC group performed significantly worse on the memory and information processing tests compared with the VPFC and HC groups.

Conclusion

This study found that the decision‐making functions of participants in the VPFC and DLPFC tumor groups were impaired to varying degrees. Among them, there was decision‐making impairment under ambiguity and under risk in the VPFC group, and there was decision‐making impairment under risk in the DLPFC group.
Understanding expert testimony on child sexual abuse denial after New Jersey v. J.L.G.: Ground truth, disclosure suspicion bias, and disclosure substantiation bias
Authors: Lyon Thomas D. , Williams Shanna , Stolzenberg Stacia N.
Published: November 2020

The New Jersey Supreme Court held in New Jersey v. J.L.G. (2018) that experts can no longer explain to juries why sexually abused children might deny abuse. The court was influenced by expert testimony that “methodologically superior” studies find lower rates of denial. Examining the studies in detail, we argue that the expert testimony was flawed due to three problems with using child disclosure studies to estimate the likelihood that abused children are reluctant to disclose abuse: the ground truth problem, disclosure suspicion bias, and disclosure substantiation bias. Research identifying groups of children whose abuse can be proven without reliance on disclosure reveals that denial of sexual abuse is common among abused children.
Effect of agronomic management on rice grain quality Part II: Nitrogen rate and timing
Authors: Wood Rachael Maree , Dunn Brian W. , Balindong Jeanette L. , Waters Daniel L. E. , Blanchard Christopher L. , Mawson Andrew John , Oli Prakash
Published: November 2020

Background and objectives

In temperate rice growing regions, the application of nitrogen (N) fertilizer is often split into two applications to reduce the risk of cold‐induced sterility associated with high N uptake. This strategy involves a basal N application applied pre‐permanent water (PW) and the second application following panicle initiation (PI). Split N application generally increases crop yield, however, data describing the impact on grain quality are relatively sparse. The objective of this study was to determine the effect of the split N method on grain quality parameters. We analyzed grain quality under various pre‐PW and PI N rates.

Findings

N applied pre‐PW increased head rice yield (HRY; the percentage of grain that remains whole or at least 75% of the original length after milling) in all tested cultivars, however, the effect of splitting the same total N rate into two doses on HRY was cultivar specific. N rate applied pre‐PW also showed a positive and negative relationship with milled grain yellowness (b*) and brightness (L*), respectively. The effect of N on amylose content was cultivar specific. The changes in quality parameters through pre‐PW N application were associated with protein content. However, total protein content did not correlate as strongly with quality parameters in the split treatments compared with the single‐dose treatments. Analysis of protein composition revealed N rate and timing affected protein composition, which had significant impacts on quality parameters, and the effects were cultivar specific.

Conclusion

These results indicate altering the nutritional management of rice changes the protein composition affecting grain quality parameters.

Significance and novelty

This study demonstrates the importance of N rate and timing of application in regard to grain quality and the significant role protein composition plays in quality characteristics.
Large‐Scale Synthesis of a Niche Olefin Metathesis Catalyst Bearing an Unsymmetrical N‐Heterocyclic Carbene (NHC) Ligand and its Application in a Green Pharmaceutical Context
Authors: Nienałtowski Tomasz , Szczepanik Paweł , Małecki Paweł , Czajkowska‐Szczykowska Dorota , Czarnocki Stefan , Pawłowska Jolanta , Kajetanowicz Anna , Grela Karol
Published: November 2020

A large‐scale synthesis of known Ru olefin metathesis catalyst VII featuring an unsymmetrical N‐heterocyclic carbene (NHC) ligand with one 2,5‐diisopropylphenyl (DIPP) and one thiophenylmethylene N‐substituent is reported. The optimised procedure does not require column chromatography in any step and allows for preparation of up to 0.5 kg batches of the catalyst from simple precursors. The application profile of the obtained catalyst was studied in environmentally friendly dimethyl carbonate (DMC). Although VII exhibited low efficiency in cross‐metathesis (CM) with electron‐deficient partners, good to excellent results were noted for substrates featuring easy to isomerise C−C double bonds. This includes polyfunctional substrates of medicinal chemistry interest, such as analogues of psychoactive 5F‐PB‐22 and NM‐2201 and two PDE5 inhibitors—Sildenafil and Vardenafil. Finally, a larger scale ring‐closing metathesis (RCM) of a Vardenafil derivative was conducted in DMC, allowing for straightforward isolation of the expected product (23 g) in high yield and with low Ru contamination level (7.7 ppm).
Synergistic Effect of Simultaneous Doping of Ceria Nanorods with Cu and Cr on CO Oxidation and NO Reduction
Authors: Rood Shawn C. , Pastor‐Algaba Oriol , Tosca‐Princep Albert , Pinho Bruno , Isaacs Mark , Torrente‐Murciano Laura , Eslava Salvador
Published: November 2020

Ceria particles play a key role in catalytic applications such as automotive three‐way catalytic systems in which toxic CO and NO are oxidized and reduced to safe CO2 and N2, respectively. In this work, we explore the incorporation of Cu and Cr metals as dopants in the crystal structure of ceria nanorods prepared by a single‐step hydrothermal synthesis. XRD, Raman and XPS confirm the incorporation of Cu and Cr in the ceria crystal lattices, offering ceria nanorods with a higher concentration of oxygen vacancies. XPS also confirms the presence of Cr and Cu surface species. H2‐TPR and XPS analysis show that the simultaneous Cu and Cr co‐doping results in a catalyst with a higher surface Cu concentration and a much‐enhanced surface reducibility, in comparison with either undoped or singly doped (Cu or Cr) ceria nanorods. While single Cu doping enhances catalytic CO oxidation and Cr doping improves catalytic NO reduction, co‐doping with both Cu and Cr enhances the benefits of both dopants in a synergistic manner employing roughly a quarter of dopant weight.
Doubling Förster Resonance Energy Transfer Efficiency in Proteins with Extrinsic Thioamide Probes: Implications for Thiomodified Nucleobases
Authors: Jena Subhrakant , Tulsiyan Kiran Devi , Kar Rajiv K. , Kisan Hemanta K. , Biswal Himansu S.
Published: November 2020

Designing a potential protein–ligand pair is pivotal, not only to track the protein structure dynamics, but also to assist in an atomistic understanding of drug delivery. Herein, the potential of a small model thioamide probe being used to study albumin proteins is reported. By monitoring the Förster resonance energy transfer (FRET) dynamics with the help of fluorescence spectroscopic techniques, a twofold enhancement in the FRET efficiency of 2‐thiopyridone (2TPY), relative to that of its amide analogue, is observed. Molecular dynamics simulations depict the relative position of the free energy minimum to be quite stable in the case of 2TPY through noncovalent interactions with sulfur, which help to enhance the FRET efficiency. Finally, its application is shown by pairing thiouracils with protein. It is found that the site‐selective sulfur atom substitution approach and noncovalent interactions with sulfur can substantially enhance the FRET efficiency, which could be a potential avenue to explore in the design of FRET probes to study the structure and dynamics of biomolecules.
Gold‐Catalyzed Annulation of 1,8‐Dialkynylnaphthalenes: Synthesis and Photoelectric Properties of Indenophenalene‐Based Derivatives
Authors: Fard Sara Tavakkoli , Sekine Kohei , Farshadfar Kaveh , Rominger Frank , Rudolph Matthias , Ariafard Alireza , Hashmi A. Stephen K.
Published: November 2020

A simple gold‐catalyzed annulation of 1,8‐dialkynylnaphthalenes utilizing a cationic gold catalyst was developed. Such a peri‐position of two alkynyl substituents has not been studied in gold catalysis before. Dependent on the substrate, the reactions either follow a mechanism involving vinyl cation intermediates or involve a dual gold catalysis mechanism which in an initial 6‐endo‐dig‐cyclization generates gold(I) vinylidene intermediates that are able to insert into C−H bonds. Indenophenalene derivatives were obtained in moderate to high yields. In addition, the bidirectional gold‐catalyzed annulation of tetraynes provided even larger conjugated π‐systems. The optoelectronic properties of the products were also investigated.