First experiment to test whether space-time is flat. II. Effects of orbit

The gyroscope in an orbiting satellite will be acted on by additional gravitational fields due to the rotation of the earth and due to the orbital velocity of the satellite. According to special relativistic gravitational theory, we deduce _L ^(S) —the gyroscope's precession rate due to the orbital velocity—and _S ^(S) —the gyroscope's precession rate due to the earth's rotation in the polar orbit case. The results are _L ^(S) = (2/3) _L ^(G) , _S ^(S) = (3/2) cos (1 - sin² cos²)^1/2 _S ^(G) , where and are the gyroscope's polar angles, and _L ^(G) and _S ^(G) are the geodetic and frame-dragging precession rates predicted by general relativity, respectively.     

An exponent bound on skew Hadamard abelian difference sets

A difference setD in a groupG is called a skew Hadamard difference set (or an antisymmetric difference set) if and only ifG is the disjoint union ofD, D(^–1), and {1}, whereD(^–1)={d^–1|dD}. In this note, we obtain an exponent bound for non-elementary abelian groupG which admits a skew Hadamard difference set. This improves the bound obtained previously by Johnsen, Camion and Mann.     

Modèles entiers des courbes hyperelliptiques sur un corps de valuation discrète

Let be a hyperelliptic curve of genus over a discrete valuation field . In this article we study the models of over the ring of integers of . To each Weierstrass model (that is a projective model arising from a hyperelliptic equation of with integral coefficients), one can associate a (valuation of) discriminant. Then we give a criterion for a Weierstrass model to have minimal discriminant. We show also that in the most cases, the minimal regular model of over dominates every minimal Weierstrass model. Some classical facts concerning Weierstrass models over of elliptic curves are generalized to hyperelliptic curves, and some others are proved in this new setting.

     

N—对甲苯磺酰基—α—氨基膦酸及其单酯的合成及活性研究

用＾３１Ｐ ＮＭＲ谱跟踪反应的方法，研究了对甲苯磺酰胺与取代苯甲醛及三氯化磷（或烷氧基二氯化磷）在乙酰氯为溶剂的条件下的类Ｍａｎｎｉｃｈ反应的机理，找到了合成标题化合物的简单方法。初步生物活性测试表明其中某些化合物具有较好的抗烟草花叶病毒活性。     

Unlabeled Fluoroimmunoassay with a Europium Chelate

Unlabeled fluoroimmunoassay with a europium chelate is described. The recommended method is simple because the complicated labeling process is omitted. The recovery of some samples ranges from 91 to 111%. The relative standard deviation of the method is less than 10%. The detection limit is about 10⁻¹⁰mol liter⁻¹antigen.     

Solid Phase Synthesis of 4H-Pyrimido[2,1-b] Benzothiazol-4-ones from Resin-Bound Cyclic Malonic Ester

The solid phase synthesis of 4H-pyrimido[2,1-6] benzothizaol-4-ones has been reported.     

THE STRUCTURAL BASIS OF THE POOR FIBRIN SPECIFICITY OF UROKINASE(Ⅰ)——KNOWLEDGE-BASED PREDICTION OF KRINGLE STRUCTURES OF UROKINASE AND ITS RELATED PROTEINS

The Kringle-1 structure of plasminogen (PGK-1), the Kringle-2 structure of tissue plasminogen activator (PAK-2) and the Kringle structure of prourokinase (UKK) has been modeled on the basis of the three-dimensional structure of Kringle-1 of prothrombin (PTK-1) at 2.8 resolution. The predicted three-dimensional structure of these Kringles shows that the binding site of PGK-1 is characterized by an apparent dipolar site, the polar parts of which are separated by a hydrophobic region. PAK-2 possesses the anionic center but has not a cationic binding center which might be provided by a guanidinium group from Arg-69 located adjacent to the Arg-71 position. UKK possesses neither the anionic binding center nor the cationic center which are probably the main reason for the poor fibrin specificity of urokinase.     

Total Synthesis of (+/-)-Leporin A

An efficient synthesis of (+/-)-leporin A (1) has been developed using a tandem Knoevenagel condensation-inverse electron demand intramolecular hetero Diels-Alder reaction to construct the key tricyclic intermediate 3 from pyridone 5 and dienal 6 in one pot in 35% yield. Hydroxylation (71%) of 3 and methylation (77%) of the resulting hydroxypyridone 2 completed the first total synthesis of (+/-)-leporin A (1).     

Solvent effects on infrared spectra of methyl 4-hydroxybenzoate in pure organic solvents and in ethanol/CCl4 binary solvents

Infrared spectroscopy studies of methyl 4-hydroxybenzoate (MHB) in 17 different organic solvents and in ethanol/CCl4 binary solvent were undertaken to investigate the solvent-solute interactions. The frequencies of carbonyl stretching vibration nu(C=O) of MHB in single solvents were correlated with the solvent acceptor number (AN) and the linear solvation energy relationships (LSER). The assignments of the two bands of nu(C=O) of MHB in alcohols and the single one of that in non-alcoholic solvents were discussed. The shifts of nu(C=O) of MHB in ethanol/CCl4 binary solvents showed that several kinds of solute-solvent hydrogen bonding interactions coexisted in the mixture solvents, with a change in the mole fraction of ethanol in the binary solvents.     

Uniform Rice-like CdS Particles Prepared from Water-in-oil Microemulsions

IntroductionNano-sized semiconductors are of great interestdue to their special optical and electronic proper-ties[1,2].As one of the mostimportantⅡ—Ⅵsemicon-ductors,CdS has importantapplications in many fields,such as the solar cell field,non linear o…