MODEL FOR THE GLOBAL IRRADIANCE OF THE SOLAR BIOLOGICALLY-EFFECTIVE ULTRAVIOLET-RADIATION ON INCLINED SURFACES

The body surface area of man is the relevant receiving surface for solar UV radiation. To consider this body surface geometry, the biologically-effective UV radiation of the solar global radiation was measured. This was done at 26 differently aligned measuring points whose orientation was determined by the angle of inclination (vertical) and the azimuth (horizontal). Approximately eight hundred sets of measurement series were carried out at 33 different sites. A simple model, developed from the data obtained, made it possible to calculate relative irradiance as a function of the angle of inclination and the ground reflection (UV albedo). Thus relative risk of solar UV exposure to different regions of the body can be assessed. In addition to this, if the irradiance on a horizontal plane (measured or calculated by a corresponding model) is taken into consideration, the absolute values for UV irradiance on tilted planes can be determined.     

ERYTHEMAL UV-B IRRADIANCE (ROBERTSON-BERGER SUNBURN METER DATA) UNDER OZONE DEFICIENCIES IN WINTER/SPRING 1993

Abstract –Robertson-Berger sunburn meter data recorded from August 1992 to May 1993 (Innsbruck, 577 m above sea level, Austria) were compared with measurements taken in previous years. In February and March 1993 instantaneous values on clear days were found to be higher by up to 37% than those registered in previous years (1986–1988). However, in winter/spring 1993 daily totals for all days, averaged over 7 days, were within the range of standard deviation of the previous years (1981–1988). Therefore the cumulative UV-B exposure of the ecosystem is within the general range of variability even under the record low ozone values in winter/spring 1993, while single peak doses were enhanced significantly.     

ERYTHEMAL UV-B IRRADIANCE (ROBERTSON-BERGER SUNBURN METER DATA) UNDER OZONE DEFICIENCIES IN WINTER/SPRING 1993

Abstract: Robertson-Berger sunburn meter data recorded from August 1992 to May 1993 (Innsbruck, 577 m above sea level, Austria) were compared with measurements taken in previous years. In February and March 1993 instantaneous values on clear days were found to be higher by up to 37% than those registered in previous years (1986–1988). However, in winter/spring 1993 daily totals for all days, averaged over 7 days, were within the range of standard deviation of the previous years (1981–1988). Therefore the cumulative UV-B exposure of the ecosystem is within the general range of variability even under the record low ozone values in winter/spring 1993, while single peak doses were enhanced significantly.     

STUDY OF DYE-SENSITIZED SYSTEMS FOR PHOTOIMAGING*

 o-Chloro-hexaarylbiimidazole (o-C1-HABI) can be sensitized efficiently by cyanine dyes, the cyclopentanone and cyclohexanone dyes, when exposed to xenon lamp (use filter cut λ≤ 400 nm). The photoreaction between the photoinitiator and the dyes was completed through an electron transfer process. Excellent results have been obtained in photoimaging studies, e.g. the resolution of the image can reach 7 μm. The influence of the content of the dyes and the heat after the exposure on the resolution of the image was investigated.     

PERSONAL DOSIMETRY OF SOLAR UV RADIATION FOR DIFFERENT OUTDOOR ACTIVITIES

Abstract Quantifying individual exposure to ultraviolet radiation (UVR) is critical to understanding the etiology of a number of diseases including nonmelanotic and melanotic skin cancers. Measurements of personal exposure to solar UVR were made in Hobart, Tasmania in February (summer) 1991 for six different outdoor activities using UVR-sensitive polysulfone (PS) film attached at seven anatomical sites. Concurrent behavioral and environmental observations were also made. To date many studies have relied on subject recall to quantify past solar UVR exposures. To gain insight into the accuracy of subject recall the measured UVR exposures received by different subjects using the PS film were compared to those calculated from personal diaries and ambient solar UVB levels from a monitoring station. In general, when UVR exposure activities took place under close supervision, good correlations were obtained between the PS badges and the ambient measurements/diaries approach. Ultraviolet radiation exposures for the field study involving 94 subjects engaged in a number of outdoor activities are presented.     

甲醇-正己烷和甲醇-环己烷溶液构型的分子模拟

用Ｍｏｎｔｅ Ｃａｒｌｏ分子模拟方法研究了不同温度条件下甲醇－正已烷、甲醇－环已烷溶液体系微观结构的变化情况。模拟表明，无论是甲醇－正已烷体系，还是甲醇－环已体系，在其溶液的近临界区，甲醇周围溶剂介质的密度最小，而甲醇分子之间的积聚最为明显。通过对氢健分析的结果表明，在溶液临界区，氢键作用与非氢键作用的距离不可区分。     

IDENTITY OF THE PHOTORECEPTORS FOR THE PERCEPTION OF IRRADIANCE IN PHOTOSYNTHETIC LIGHT ACCLIMATION IN TOMATO*

The photoreceptors involved in the photosynthetic acclimation of tomato (Lycopersicon esculentum Mill.) to increased irradiance were investigated. Plants were transferred from 100 p.mol m^?2 s^?1 cool white fluorescent light to higher irradiances of white light or white light supplemented with blue, red, green or yellow light. In these experiements light of all wavelengths tested was capable of causing acclimation as measured by the rate of light-saturated photosynthesis. It was concluded that the photosynthetic system rather than the blue-absorbing photoreceptor or phytochrome system acts as the photoreceptor for increased irradiance. No acclimation was observed in response to increased CO₂ levels, but increasing light integral at a constant irradiance was effective in bringing about acclimation. We conclude that acclimation is a response to increased photosynthetic light capture rather than increased photosynthetic carbon fixation, and involves a photon counting mechanism.     

COMPUTER SIMULATION OF MISCIBILITY AND SELF-ASSEMBLY STRUCTURE FOR POLYMER-CONTAINING SYSTEMS WITH SPECIAL INTERACTIONS

The miscibility and structure of A-B copolymer/C homopolymer blends with special interactions were studied by aMonte Carlo simulation in two dimensions. The interaction between segment A and segment C was repulsive, whereas it wasattractive between segment B and segment C. In order to study the effect of copolymer chain structure on the morphologyand structure of A-B copolymer/C homopolymer blends, the alternating, random and block A-B copolymers were introducedinto the blends, respectively. The simulation results indicated that the miscibility of A-B block copolymer/C homopolymerblends depended on the chain structure of the A-B copolymer. Compared with alternating or random copolymer, the blockcopolymer, especially the diblock copolymer, could lead to a poor miscibility of A-B copolymer/C homopolymer blends.Moreover, for diblock A-B copolymer/C homopolymer blends, obvious self-organized core-shell smicture was observed inthe segment B composition region from 20% to 60%. However if diblock copolymer composition in the blends is less than40%, obvious self-organized core-shell structure could be formed in the B-segment component region from 10 to 90%.Furthermore, computer statistical analysis for the simulation results showed that the core sizes tended to increasecontinuously and their distribution became wider with decreasing B-segment component.     

USE OF REGRESSION ANALYSIS TO ESTIMATE UV SPECTRAL IRRADIANCE FROM BROAD BAND RADIOMETER READINGS UNDER FS-40 FLUORESCENT SUNLAMPS FILTERED WITH CELLULOSE ACETATE

Abstract— Weighted and unweighted UV spectral irradiances were measured under a 2-lamp fluorescent fixture containing Westinghouse FS-40 fluorescent sunlamps filtered with (6 h aged) 0.127 mm (0.005 in.) cellulose acetate by use of newly developed broadband UV radiometers and an automated UV spectro-radiometer. Measurements were taken at 10-cm intervals between 20 and 110 cm from the lamps. Correlations were determined between sets of data measured with the broadband radiometers and the UV spectroradiometer.
By use of linear regression analyses on the weighted and unweighted spectral data, regression equations were developed for predicting UV-B irradiance (unweighted mWm-²), biologically effective UV (BUV) (weighted mWm) in the 280–320 nm (UV-B) region, UV-B sun equivalents, and incident flux density in the UV-B region in photons m-²× 10²¹ integrated over a 6-h exposure. Examination of the correlation coefficients ( r values) indicated that agreement was excellent between measured and predicted values for all comparisons (r values from 0.9972 to 0.9998).
Use of regression equations should permit accurate. rapid estimation of both weighted and unweighted UV irradiances at any location in an experimental set-up and provide a useful means for intra- and inter-laboratory comparisons of spectral measurements, made in the interagency BACER program under FS-40 fluorescent sunlamps filtered with 0.127 mm cellulose acetate (aged for 6h).     

COMPUTER SIMULATION OF POLYMER SOLUTION THERMODYNAMICS

The statistical counting method for the computer simulation of the ther-modynamic quantities of polymer solution has been reviewed. The calculating results fora single athermal chain confirm the theory of the renormalization group. The results forthe athermal solution are consistent with the scaling law of the osmotic pressure with theexponent 2.25. The results for a single chain with the segmental interaction are in a goodagreement with the exact results obtained by the direct counting method. The results forthe polymer solution show us that the Flory-Huggins parameter is strongly dependent onboth the polymer concentration and the interaction energy between segments. Monte carlo simulation; Polymer solution; Thermodynamic quantities;Translational entropy; Conformational entropy; Scaling law     

TETRACHLOROPYRIDINE: A NEW REAGENT FOR THE DEHYDRATION OF ALDOXIMES UNDER MICROWAVE*

ABSTRACT

Dehydration of aldoximes to nitriles using tetrachloropyridine under microwave in dry media is described. The procedure is applicable to a variety of aldoximes and the reagent can be recycled and reused.

     

EFFECT OF ACIDITY ON ACID-SENSITIVE UV CURING SYSTEM*

By using diphenyliodonium salts with different counterions as photo acid generators (PAGs), theeffect of acidity on ring-opening polymerization of epoxy monomers and polycondensation of polyol withhexamethoxymethyl melamine (HMMM) was studied. The result shows that the rate of ring-openingpolymerization is evidently dependent on the acidity of the acid and strong photo-generated acid is required.However, there is a leveling effect in the polycondensation system; if the photo-generated acid is strongerthan protonated HMMM, the acidity does not obviously affect the polycondensation rate.     

ACTION SPECTRA FOR THE PHOTOLYSIS OF 5-IODODEOXYURIDINE IN DNA AND RELATED MODEL SYSTEMS: EVIDENCE FOR SHORT-RANGE ENERGY TRANSFER*

Abstract— A variety of polynucleotides containing 5-iodouracil residues were irradiated in aqueous solution with wavelengths between 240 and 313 nm. From the rate of deiodination the photochemical cross sections (a_B) were determined as a function of the irradiation wavelength (A). The expression was used to relate the observed values of _B to the intrinsic quantum yield, φ_INT, and to the absorption cross sections, and for the iodinated and noniodinated residues, respectively. φ_INT is the probability an excited iodouracil residue will deiodinate, while the parameter b is a measure of the number of noniodinated bases which contribute their excitation energy to the deiodination process. For IdUrd and poly(5-iodouridylic acid), the average values of φ_INT calculated from the experimental _B values were 0.0202 and 0.0188, respectively, for irradiation in air. In native, denatured, and depurinated DNA in which IdUrd was substituted for 10% of the Thd, the average φ_INT values were 0.0069, 0.0088, and 0.0153, respectively, indicating an enhancement in φ_INT upon decreasing the order of the polynucleotide. In contrast, the average values of b bor the same set of compounds were found to be 4 , 2 and 0.4, respectively, indicating a decrease in b with decreasing polynucleotide order, i.e. a loss of base stacking decreases the extent of energy transfer. A value of b= 4 for native DNA is assumed to mean that the extent of energy transfer in native DNA is limited to four base donors per iodouracil residue serving as an energy trap.     

COMPUTER SIMULATION OF A SINGLE POLYMER CHAIN IN DIFFERENT SOLVENTS

In the present paper, the behavior of a single polymer chain under various solvent conditions was modeled by self-avoiding walks (SAW) with nearest neighbors attraction Δε on a simple cubic lattice. Determination of the θ-condition wasbased on the numerical results of the mean square radius of gyration and end-to-end distance. It was found that at the θtemperatue Δε/kT equals -0.27. The exponents a in the Mark-Houwink equation with different interaction parameters areconsistent with the results of experiments: under θ-condition, a = 0.5, and for a good solvent α= 0.74-0.84, respectively.     

FUNCTIONS OF POLYAMINES IN ROSIN SIZING UNDER NEUTRAL PAPERMAKING CONDITIONS

Functions of the polyamines in neutral rosin sizing were investigated using X-ray photoelectron spectroscopy(XPS) and laser diffraction particle analysis. The polyamine with a higher charge density and a smaller unite size could retainmore rosin and cover larger fiber surfaces. The XPS spectra demonstrated that polyallylamine.(PAAm) and polyvinylamine(PVAm) could react with a rosin size to form a-OC-N-CO-structure, but polydimethylamino ethyl methacrylate(PDMAEMA) could not, The formation of this structure may be a key step for effective sizing.     

MOLECULAR SIMULATION STUDY ON THE CHANGE OF POLYMER STRUCTURE DURING YIELDING*

A better understanding of a recently raised argument on whether there occurs a structure change during yieldinghas been acquired by using molecular simulation. That is, when monitoring the displacements of all atoms before and afterthe yield, a structure transition does occur, which is the "atomic jump" that coordinates the amount of the atoms in thepolymer and makes a large step beyond～0.05 nm for all those atoms. Results indicate that the complex of polymer chainpacking induces the multiple atomic jumps around the yield point. This explains why polymers have a broader yielding peak.     

PHOTOPOLYMERIZATION IN THE MICELLAR SYSTEMSⅡ THE CATALYSIS OF PKT FUNCTIONAL MICELLE*

A kind of cationic compounds, having benzophenone end group and various length chain (PKT) (BP-CH_2N+R_2R'·X~-, R&R' different chain iength alkyl group) were used as photosensitizers. Various BP/TEA systems have been used for study, The efficiency of MMA photopolymerization initiated by them shows PKT>BP in homogeneous water solution and PKT> BP/CTAB in micellar water solution. The results obtained indicate that catalytic effects of PKT type functional micelles are far greater than that of common micelle with the enhancement of polymerization rate over 10 times compared with BP in water solution. The catalytic role, reaction character of PKT, effect of counter ions and retarding effect of oxygen have also been discussed.     

STUDY ON MEAN-SQUARE RADIUS OF GYRATION FOR POLYALKYLENEOXIDES

Taking account of the effect of heteroatoms in backbone, this article dealt with themean-square radii of gyration of polyalkyleneoxides by the approach of matrix algebrain accordance with the rotational isomeric state model. Numerical calculation with theparameters available in the literatures indicated that the dependence of on themolecular weight can be expressed by the general formula: = aM~b     

POLYMER SUPPORT EFFECTS OF METAL COMPLEXES FOR CATALYSIS*

In the course of investigating the catalytic behavior of metal complexes forring opening metathesis polymerization of cycloolefins, metathesis, hydroformylation andselective hydrogenation of olefins experimental results time and again indicate the pres-ence of effects of macromolecular supports -the utilization of macromolecular supportsincreases obviously the activity, selectivity, and stability of the catalysts and so as to in-crease the conversion of substrates, yields of reactions, properties of formed polymers andso on. Discussed these effects on the basis of the authors' experiments.     

THE ASYMMETRIC SYNTHESIS OF AMINO ACIDS UNDER POLYMER-SUPPORTED PHASE TRANSFER CATALYTIC CONDITION

The optical α-amino acids were synthesized under room temperature byalkylation of N-(diphenyl methylene) glycine t-butyl ester under polymer-supported phasetransfer conditions using polymer-supported cinchonine (or quinine) alkaloids as chiralphase transfer catalysts and dichloromethane as solvent, followed by hydrolysis of theabove intermediates introduced to the final products-optical α-amino acids. This is anew method for the asymmetric synthesis of α-amino acids. The influences of catalyst,temperature, substrates, and organic solvents on the chemical yield and optical purities ofproducts were studied.