宋元海洋知识中的“海”与“洋”

宋元时期随着航海实践的空前发展,海洋地理空间认知中“九州—四海”的“天下”格局的知识框架逐步被航海实践突破和“遗忘”,在海洋地理认知上抽象的“海”向具象的“洋”的转变,海洋被以多种方式划分和命名为不同的“洋”。宋元对“洋”的划分和命名仍表现为区域性知识,但其基于航海实践的知识生成路径奠定了不同朝代、不同国家形成共同海洋知识和海洋观念的逻辑基础。在中国接受和融入世界共同海洋知识和海洋观念的过程中,宋元海洋实践的空前发展开启了具有重要转折意义的新阶段。     

On triazoles. XXXIX. Synthesis and structure of some 1,2,4-triazolo[1,5-a]pyrimidin-5-one oximes

Some 1,2,4-triazolo[1,5-a]pyrimidin-5-one derivatives 1 and their alicyclic condensed ring analogues 2-3 were converted through the corresponding “imino chlorides” 4-6 to the oximes 7-9 . The “E” isomeric structure of the products obtained was proven with the use of cmr using the spectral data of the corresponding “benzyloximino” derivatives 10-12 prepared as model compounds.     

Lotus-Effect® – surfaces

Surfaces are often characterized with phrases like “easy to clean”, “dirt repellent”, “dirt resistant”, “self cleaning” or “ Lotus -Effect^®”. Every one of those phrases is used to describe a behavior of surfaces - similar to each other but still different. This article is providing the definition of the Lotus -Effect^®, techniques to manufacture self cleaning surfaces and methods to characterize them as well. How to generate a self cleaning surface depends on the substrate and the use later on. It can be as easy as a spray on but on the other hand as complicated as a three step process. Self cleaning surfaces are defined by four parameters - contact angle, roll-off angle, hystereses and C.I.E-Lab Δ-L value.     

Erratum to: Removal of Some Radionuclides Using Stannic Silicovanadate as Inorganic Ion Exchanger

Russian Journal of Applied Chemistry - In affi liation section, line 3, “Bisha University” should be replaced by “University of Bisha.”     

Correction to: CeO2 promoting allyl alcohol synthesis from glycerol direct conversion over MoFe/CeO2 oxide catalysts: morphology and particle sizes dependent

Research on Chemical Intermediates - In the original publication of the article, the chemical compounds “enthanal” and “propanal” were incorrectly published as...     

Two aspects of water in self-heating risk of aluminium powders: calorimetric study

Journal of Thermal Analysis and Calorimetry - Two samples (“O” and “C”) of aluminium-based powders were calorimetrically investigated with respect to the self-heating risk...     

Specific Role of Reactor Configurations on the Mass Transfer and Energy Yield: Case of “Batch” and "Circulating” Gliding arc Liquid–Gas Reactors—Part 1: Experimental Study

Plasma Chemistry and Plasma Processing - The mass transfer and energy efficiency in the “batch” and “Circulating” gliding arc configuration reactors for the direct...     

Synthesis of benzo[c]phenanthrene dihydrodiols

Unlike most other alternant polycyclic aromatic hydrocarbons which are carcinogenic, benzo[c]phenanthrene has a “fjord region” instead of a “bay region”. For this reason, we have synthesized the three metabolically possible trans 1,2-, 3,4-, and 5,6-dihydrodiols to test them for carcinogenic activity.     

The Role of Self‐Dilution in Step‐Growth Polymerizations

In step‐growth polymerizations, the molar concentration of reactive linear species (oligomers and polymers) decreases with higher conversions and finally reaches zero at 100% conversion. This self‐dilution favors cyclization at the expense of chain‐growth. Cyclization reduces the average lengths of the linear species, and thus, induces a kind of “self‐acceleration”. Both effects together overcompensate the decreasing cyclization tendency resulting from increasing chain lengths. This influence of the self‐dilution is also operating in the case of “ab_n” monomers, so that at 100% conversion (defined for the “a” functional groups) all hyperbranched polymers will have a cyclic core. With modifications, the “law of self‐dilution” also applies to “a₂ + b₃” or “a₂ + b₄” polycondensations. Furthermore, the “law of self‐dilution” is valid for both kinetically‐ and thermodynamically‐controlled polycondensations.

     

Bioactive principles in exudate gel from the leaf of Aloe fleurentiniorum,traditionally used as folkloric medicine by local people of Aridah and Fayfa mountains,Saudi Arabia

Aloe fleurentiniorum is a desert plant that is occasionally used to treat wounds by local people of Aridah and Fayfa mountains in Saudi Arabia. However, medicinal value of the plant has not been scientifically established. The purpose of this study was to determine the bioactive phytocomponents contained in the exudate gel (EG) from the leaves of Aloe fleurentiniorum using GC–MS and FT-IR studies, as well as antibacterial assays. Medicinally important bioactive compounds were identified using GC–MS analysis. The bioactive compounds are “pregn-5-ene-3α,20-diol”, “16α-methyl-pregnane-11,20-dione”, “3-hydroxy-(3α,5α)-, ursodeoxycholic acid”, “1-heptatriacotanol”, “allopregnane-7α,11α-diol-3,20-dione”, “D-arabino-hexopyranoside”, “2-octadecenoic acid methyl ester”, “D-ribo-hexose,2,6-dideoxy-3-O-methyl glucosamine”, “N-acetyl-N-benzoyl-alpha-D-glucopyranoside”, “nonyl 1-thio pregnenolone”, “5-cholestene-3-ol, 24-methyl-cholestanol”, and “D-allose hexadecanoic acid methyl ester”. Furthermore, specific groups and their respective chemical compounds were identified via FT-IR spectroscopy studies. The FT-IR spectroscopy of EG showed various functional groups at 3354, 2945, 2832, 2523, 2046, 1707, 1451, 1108, 1031, 880, 737 and 610 cm⁻¹. The FT-IR peaks revealed the likely presence of various compounds such as glycosides, flavonoids, steroids, saponins, flavonoids, amino sugars, cutin and isothiocyanate. Moreover, EG produced a wide range of antibacterial effects on some screened human pathogenic bacteria.     

1,5-naphthyridines. Synthesis of 7-chloro-4-(4-diethylamino-1-methylbutylamino)-2-methoxy-1,5-naphthyridine and related compounds

The synthesis of 7-chloro-4-(4-diethylamino-1-methylbutylamino)-2-methoxy-1,5-naphthyridine, a compound which incorporates the structure of both chloroquine (a schizontocidal drug) and pamaquine (a gametocytocidal drug), has been carried out. In addition, two structurally related derivatives, the, “5-azachloroquine” and the “5-azapamaquine,” have also been obtained by multi-step syntheses. “5-Azachloroquine” possesses good antimalarial activity against Plasmodium berghei. The compound was also found to be less toxic than the known 4-aminoquinoline and 8-aminoquinoline antimalarial drugs.     

Unusual ring opening of a Cyclopropylideneamine derivative during a favorskii-type rearrangement of α-Chloroketimines

The reaction of N-(3-chloro-3-methyl-2-butylidene)amines (i.e. α-chloroketimines) with lithium diisopropylamide in tetrahydrofuran gave rise to an unexpected reaction leading to 2-(N-alkylimino)-3,3-dimethyl-1-isopropyl-5-(2-methylpropylidene) pyrrolidines in good yields. The reaction mechanism is interpreted in terms of a Favorskii-type 1,3-dehydrochlorination affording intermediate cyclopropylideneamines (N-analogues of cyclopropanones), which “dimerize” in an unusual way. This mechanism entails a “normal” opening as well as an “abnormal” opening of incipient cyclopropylideneamine adducts. This rearrangement represents an example of the scarcely reported abnormal opening of functionalized cyclopropylamines.     

Gas Chromatographic Separation of Enantiomers it

Separation methods for the resolution of “optical isomers” (especially enantiomers) are developed to solve either of two basic problems: 1) the need to obtain, in optically pure form, one antipode or the other on a scale suitable for further chemical use-i.e.-“preparative” or 2) the analysis of the extent of racemization or “optical resolution” of a mixture of enantiomorphs on a scale sufficient for quantitative analysis-i.e.-“analytical”. The most economical, large-scale separation methods in use today are not chromatographic in nature but rather range from such common, general unit operations as recrystal1ization to very specific biological degradation.lS2 Chromatographic methods are generally limited to systems in which analytical data is the desired end product or in which only relatively small amounts of resolved material are needed.     

Erratum to: “Physicochemical Transformations in Multicomponent Melts Containing Uranium,Zirconium, and Iron Oxides and Calcium Silicates and Aluminates”

Russian Journal of Applied Chemistry - Page 843, Fig. 7. “G, g cm–2 s–1” should be replaced by “G × 105, g cm–2 s–1.”     

The diastereospecific aprotic conjugate addition reactions of allylic anions-mechanistic aspects.

A ten-membered cyclic “chair-chair” - or “$\text{trans}$-decalyl”-like TS is proposed to account for the diastereospecific aprotic conjugate addition reactions of allylic carbanions bearing polar, charge-stabilizing groups.     

Laser-induced Graphene in Facts,Numbers, and Notes in View of Electroanalytical Applications: A Review

In this review, laser-induced graphene (LIG) -based electrodes are discussed by covering such essential areas, as a characterization of LIG material properties necessary for electroanalysis, including data on LIG sheet resistance, wettability, spatial resolution, electrochemical characteristics, as well as correlations of “process” - “properties” - “electroanalytical characteristics”of LIG-electrodes. Moreover, typical and innovative LIG-based electrodes designs for electroanalytical applications, including combined multi-analyte multimodal wearable sensors, interdigitated electrodes, are shown. The essential data related to LIG in electroanalysis are summarized in tables. The authors also discussed recent LIG-based electroanalytical applications. Close attention has been paid to LIG glucose sensors and biosensors.     

A theoretical study of the force field for carbon trioxide

Geometries force constants and harmonic frequencies are calculated for the cyclic (dioxirane) structure of CO₃ by ab initio SCF methods using the 3-21G, 3-21G(*). 6-31G and 6-31G* bases calculated frequency shifts for isotopomeric species agree with experiment and lend support to the vibrational assignments of Jacox and Milligan. Earlier arguments for and against the cyclic, cyclic and open structures of CO₃, based upon the “physical reasonableness” of valence force constants are shown to be invalid owing to the dependence of conventional “rigid” force constants upon the choice of valence coordinates. The use of “relaxed” force constants as a basis for meaningful comparison of force fields for molecules described by different sets of redundant valence coordinates is demonstrated.     

Study of localizability for some small molecules

Localized charge densities of some small molecules at their experimental and calculated equilibrium geometries have been studied using the 6-31G and 6-31G/d basis sets. Introducing polarization functions it has been found that the bond-pair charge distributions are “more”, while the lone-pair- ones are “less” localized at their theoretically determined total-energy minima than at the corresponding experimental geometries.     

Mass spectra of 6-ketononanolides and related ketolactones

The mass spectral fragmentation of 6-ketononanolides, 6- and 7- ketodecanolides, 7-ketoundecanolides and 9-ketotridecanolide has been partially correlated via high resolution measurements and the use of methyl substituted derivatives. Moities characteristic of the “lactone side” and the “non-lactone side” of the ketolactones can be described. Metastable transitions and decoupled measurements are offered as additional evidence for some of these pathways.     

超音速射流中I2的弛豫过程 I. 转动弛豫

用激光诱导荧光法测量I_2在He, Ar, N_2等载气射流中转动温度沿射流轴线的分布。分析了速度滑移效应对转动弛豫的影响, 结果表明, 在超音速射流条件下转动弛豫的效率极高。