确定性网络随机多点r—辐射中心选址理论与算法

在Edward. Minieka提出的γ—辐射选址理论与算法的基础上,本文提出了在确定性网络中选择多个随机服务能力设施为最多用户服务的选址理论与算法。

Effects on Agronomic Traits of M_1 by Pollen of Upland Cotton Irradiated by ^(60)Co-γ Ray

[Objective] The aim was to provide reference for research on radiation and breeding of cotton pollen through irradiating common ripe pollen grain of upland cotton by 60Co-γ Ray of varied doses. [Method] Ripe pollen grains of upland cotton were irradiated by 60Co-γ Ray with doses of 5, 10, 15, and 20 Gy, respectively, to learn radiation effect and select appropriate dose. [Result] Most properties of M1 obviously showed variation when dose was over 10 Gy; vitality, growth, and fertility were greatly inhibited when dose was 15 Gy which was almost semi-lethal concentration, and variation species were richest at the same time, which provided materi- als for practical breeding. [Conclusion] 60Co-γ Ray of 15 Gy is more suitable for mutagenesis research on ripe pollen grains of upland cotton.

Study on γ-Ray Irradiation Mutation of Bacillus subtilis NCD-2

[Objective] To study the effect of 60Co γ-rays irradiation on Botrytis cinerea biocontrol strains—Bacillus subtilis NCD-2. [Method] NCD-2 cells were irradiated at different doses of γ-rays from 100 to 2 000 Gy. The strains were screened by plate confrontation method and Oxford cup diffusion. [Result] The curves of the relationship of irradiation dose and mutation and lethal rate were obtained. The results showed that lethal rate increased with the increasing of irradiation dose. The lethal rate of 1 000 Gy irradiation dose reached 99.50%. The mutation rate increased below 500 Gy and decreased above 500 Gy. The highest mutation rate occurred when the irradiation dose was between 400 and 700 Gy, and the average mutation rate was above 15%. The optimal irradiation dose was 500 Gy, when the average mutation rate was 26.51% and lethal rate was 77.71%. [Conclusion] This study provided references for γ-rays irradiation mutation of Bacillus subtilis.

Feasibility of using recycled CRT funnel glass as partial replacement of high density magnetite sand in radiation shielding concrete

The recycled cathode ray tube(CRT)funnel glass was used as replacement of magnetite sand in the concrete,and its mass replacement rates were 0,20%,40%and 60%,respectively.The flowability,apparent density and mechanical properties of the radiation shielding concrete were investigated,while itsγ-ray radiation shielding parameters such as linear and mass attenuation coefficients(μandμm,respectively),thickness values of half-value layer(hHVL)and tenth-value layer(hTVL)were obtained by theoretical calculation,experiment and Monte.Carlo N-Particle(MCNP)simulation code.The experimental results show that the flowability of the concrete increases significantly,whilst its apparent density,compressive strength and static elastic modulus decrease slightly.The calculated,simulated and experimentalμm,μ,hHVL and hTVL values of all concrete samples are very consistent at the sameγ-ray photon energy,and it is feasible to use MCNP code to simulateγ-ray radiation shielding parameters of materials.The calculated results show that in a wide range ofγ-ray photon energy,theμm value of the concrete with CRT funnel glass replacing magnetite sand is improved effectively,and its radiation shielding performances are the same as those of the control concrete(M.1).By comprehensively comparing the flowability,mechanical properties andγ-ray radiation shielding properties,the concrete samples with 20%.40%funnel glass as fine aggregate have good performances.

Effect of PLA/ZnO Packaging and Gamma Radiation on the Content of Listeria innocua, Escherichia coil and Salmonella enterica on Ham during Storage at 4℃

The effect of ZnO and low y-radiation on PLA based-films was investigated to be used for food packaging application. Ham slices were inoculated with E. coli, L. innocua and S. enterica and then covered with PLA and PLA/5% ZnO films. The samples were irradiated with a y-radiation dose of 0.3 kGy at dose rate of 13.5 kGy/h. Microbiological analysis was performed at 0, 1 and 5 days on samples stored at 4 ℃. Results showed that no consistent reduction of bacteria was obtained, even at the fifth day of storage, when the ham was covered with PLA/5% ZnO film and no γ-radiation was performed. The use of γ-radiation results necessary to reduce the bacteria growth. In fact E. coli and S. enterica were not detected after 5 days of storage; whereas in the case of test with L. innocua a reduction of 1.3 log CFU/g was observed after 5 days of storage. The antibacterial results indicate that the presence of ZnO in PLA film is effective only for E. coll. The differences of the results obtained here with those reported in literature （where ZnO particles are reported to be very effective as antimicrobial material） are accounted for the different methodologies used. In conclusion considering the positive results, even if small, obtained here at least only for the E. Coli and considering that PLA/5% ZnO film shows, compared to plain PLA film, good tensile properties （especially Young＇s modulus and stress at yielding） and good permeability （to O2 and CO2） induce to consider the PLA/5% ZnO composite film usable for food packaging when long shelf life and food safety are required, considering also that it is biodegradable and compostable.

Efficient Extraction of Tea Saponin from Tea Seed Meals by ^(60)Coγ-Irradiation

In order to simplify the extraction process of tea saponin and improve its extraction rate,tea seed meals was taken as materials to explore effects of ^(60)Coγ-irradiation and H_(2)O_(2) on the extraction rate of tea saponin.The results showed that the optimal crude extract condition of tea saponin was 6%H_(2)O_(2) and an irradiation dose of 5 kGy,the extraction rate was 46.4%.However,when the irradiation dose and the H_(2)O_(2) concentration continued to increase,the extraction rate of tea saponin decreased.After flocculate extraction,the tea saponin content increased from 40.80%to 48.32%.Foaming property test results showed that the higher the tea saponin content in the solution was,the higher the foaming height will be,and the foam had a certain stability.This work provided a new method for the extraction of natural products,usingγ-ray irradiation and H_(2)O_(2) pretreatment to improve the extraction rate,and this was of great significance for industrial extraction.

Differential activation of mitogen-activated protein kinases by γ-irradi-ation in IEC-6 cells: Role of intracellular Ca^(2+)

Objective: To explore the effects of γ-irradiation on mitogen-activated protein kinases (MAPKs) and role of intracellular calcium in this event in intestinal epithelial cell line 6 (IEC-6 cells). Methods: After cultured rat IIEC-6 cells with or without the pretreatment of intracellular Ca2+ chelator were exposed to Y-ir-radiation of 6 Gy, the total and phosphorylated MAPKs in the cells were determined with Western blotting and apoptosis was examined with flow cytometry. Activities of Extracellular signal-regulated protein kinase (ERK) and p38 MAPK were determined by using immuoprecipitation followed by Western blotting. Results: In response to γ-irradiation, phosphorylation of ERK was not significantly observed, while the levels of phosphorylated c-Jun NH2-terminal kinase (JNK) and p38 MAPK were increased in 30 min and reached the peak 2 h after exposure to 6 Gy γ-irradiation, though the cell viability was significantly lowered 12 h. On the other hand, no obvious changes were seen in the total protein levels of ERK, JNK and p38 MAPK. Chelation of intracellular Ca2+ almost completely suppressed the JNK and p38 MAPK phosphorylation induced by γ-irradia-tion, but removal of external Ca2+ had no such effect. Activation of p38 MAPK, but not of ERK, was seen to have a correlation with γ-irradiation induced apoptosis. Conclusion: The results suggest that γ-irradiation is a potent activator for JNK and p38 MAPK, and Ca2+ mobilized from intracellular stores plays an important role in the activation of MAPKs and the induction of apoptosis in IEC-6 cells.

Radiation Absorption Mechanism in Nonvolatile MNOS Structure

The γ-ray radiation will speed up the discharge of the storedcharge in nonvolatile MNOS structure. The radiation absorptionmechanism to enhance the discharge is discussed. A direct radiationemission model from the interface traps distributing both in energylevel and in space is given. The theoretical results based on thismodel are in good agreement with experimental measurements.

Effect of γ-ray Radiation on the Loss of Optical Fiber in Visible Range

The mechanism of γ-ray radiation induced absorption loss of the optical fiber in visible range is analyzed. According to the mechanism, the quantitative relation between loss in optical fiber and γ-ray cumulation dose is found by use of methods of solid physics and statistic physics. This quantitative relation is certified in terms of the results of radiation experiment.

Biocidal Effect of Gamma Radiation on the Ecology of Filamentous Fungal Populations Associated with Stone Deterioration

This study focused on the identification of the filamentous fungi associated with soapstone samples exposed to outdoor conditions and the biocidal effect of gamma radiations on isolated fungal populations in Minas Gerais State in Brazil. Two soapstone blocks were placed outdoors under tropical environmental conditions for 12 months. A total of 9 filamentous fungal populations were identified on their surfaces, namely Acremomium （cf.） alternatum, Alternaria alternata, Aspergillusfumigatus, Calcarisporium （cf.） arbuscula, Cladosporium cladosporioides, Curvularia lunata, Epicoccum nigrum, Fusarium equiseti and Penicillium citrinum. The gamma radiation assay was then carried out as a test of biocidal action by exposing all fungal populations to the ionizing radiation. The results showed that only the C. cladosporioides species was resistant to this biocidal agent, since it was able to increase its population post exposure. Scanning electron microscopy images identified the microbial colonization on the soapstone blocks and the stone elementar composition was analyzed by energy dispersive X-ray spectrometry. After treatment, there was no structural and aesthetic alteration in the soapstone samples, and evidencing that gamma radiation can be used as a biocidal agent. However, the resistance of the black fungal population indicates caution in the choice of gamma irradiation as biocidal treatment.

Improvement of Rice （Oryza sativa L.） var. Ciherang and Cempo Ireng Productivity Using Gamma Irradiation

Rice is the source of important food in the world. The demand of rice tends to increase every year, thus research to increase genetic variation of rice by gamma irradiation has been conducted. This research aimed to study the influence of gamma irradiation doses on the vegetative growth, yield and quality. The randomized completely block design was used with two factors --gamma irradiation doses and varieties. Two rice varieties were Ciherang and Cempo Ireng, while doses of gamma irradiation consisted of six levels： 0, 100, 200, 300, 400 and 500 Gy. The results indicated that the treatment of 200 Gy gamma irradiation to Ciherang could improve the number of grains/panicle, protein content, degraded plant height and amylose contents. Gamma irradiation to Cempo Ireng at dose of 200 Gy could improve the number of grains/panicle, 1,000 grain weight, while it decreased days to 50% heading and plant harvest age.

In-situ Enhanced Toughening of Poly（ethylene terephthalate）/elastomer Blends via Gamma-Ray Radiation at Presence of Trimethylolpropane Triacrylate

Gamma-ray radiation has always been a convenient and effective way to modify the inter- facial properties in polymer blends. In this work, a small amount of trimethylolpropane triacrylate （TMPTA） was incorporated into poly（ethylene terephthalate） （PET）/random terpolymer elastomer （ST2000） blends by melt-blending. The existence of TMPTA would induce the crosslinking of PET and ST2000 molecular chains at high temperatures of blend- ing, resulting in the improvement in the impact strength but the loss in the tensile strength. When the PET/ST2000 blends were irradiated by gamma-ray radiation, the integrated me- chanical properties could be enhanced significantly at a high absorbed dose. The irradiated sample at a dose of 100 kGy even couldn＇t be broken under the impact test load, and at the same time, has nearly no loss of tensile strength. Based on the analysis of the impact- fractured surface morphologies of the blends, it can be concluded that gamma-ray radiation at high absorbed dose can further in situ enhance the interfacial adhesion by promoting the crosslinking reactions of TMPTA and polymer chains. As a result, the toughness and strength of PET/ST2000 blend could be dramatically improved. This work provides a facial and practical way to the fabrication of polymer blends with high toughness and strength.

ASSESSMENT OF COLLECTIVE DOSE FOR TRAVELLERS BY WATERS

People travelling by air will receive more exposure dose and by water will receive less one.According to statistic data from the Ministry of Communications in 1988,the turnover in that year was abode 2×1010 man·km.The total number of fishermen for inshore fishing was nearly two million reported by Ministry of Agriculture,Animal Husbandry and Fishery.Based on measured data on 212 points in six typical shipping lines of inshore lines and inland rivers,and the total voyage is 5625km,the average natural radiation dose rate received by travellers was calculated.Worn that assessment of collective effective dose for passengers by Water and fishermen was derived.The value is 32.7 man.Sv for passengers and 265.3 man.Sv for fishermen.

Radiation-Chemical Degradation of Oxalic Acid in Water Solutions

Co60 gamma ray radiolysis of aqueous oxalic acid solution （1 × 10-2 M） was investigated within the dose range up to 80 kGy. The value of pH increases from 2.0 to 4.0 and approximately 90% of oxalic acid and its derivatives are degraded at the dose of 80 kGy. Dissolved O2 affects to the degradation of oxalic acid at the initial stage due to total consumption of O2 at the dose of 2 kGy. Formation of CO2 occurs at a higher rate at the initial stage until the dissolved 02 is fully consumed. The kinetic model of oxalic acid degradation in aqueous solution under the gamma irradiation was tested. The suggested mechanism complies with the experimental data both of our own and of that reported earlier.

Characterization of pH-sensitive Poly (acrylic acid-co-N-vinyl-2-pyrrolidone) Hydrogels Prepared by Gamma Radiation

The pH-sensitive copolymer hydrogels were prepared with the monomers of acrylic acid and N-vinyl-2-pyrrolidone based on gamma radiation technique. The morphology of the hydrogels was monitored by using scanning electron microscope. The influence of absorbed dose, monomer composition and concentration on the swelling ratio (SR) of the hydrogels were investigated in detail. The effect of pH and temperature of the swelling medium on the swelling behavior of the hydrogels were also examined. The results show that the SR of the copolymer hydrogels decreases with the monomer concentration and absorbed dose increasing. The copolymer hydrogels show a better pH-sensitive behavior. In alkaline solution, the SR of the hydrogels is much higher than in acid solution.

The Effectiveness of Radiation Damage Reduction in Mice by Laser Light in Dependence of the Time Interval between Exposures

A research was carried out to determine the period of time during which it is possible to reduce the radiation damage in mice by means of laser radiation （650 nm） after gamma irradiation. First, the mice were exposed to γ- radiation （whole body irradiation）, then after 2 h or 24 h they were irradiated with laser radiation. The results of these studies have shown that the use of laser irradiation to reduce radiation damage in mice is effective 24 h after the exposure to 5 Gy ionizing radiation which leads to the bone-marrow clinical form of the ARS （Acute radiation sickness）. In case of the lethal dose of ionizing radiation 7 Gy （the transitional clinical form of the ARS）, the increase in life expectancy of mice is observed using laser radiation both 2 and 24 h after the exposure to γ- radiation, but the effectiveness of the laser used 2 h after the ionizing radiation is significantly more efficient.

The Best Dose for Sterilisation of Greenhouse Whitefly, Trialeurodes vaporariorum （Westwood） （Hem.： Aleyrodidae） by Gamma Radiation

Greenhouse whitefly （GHWF）, Trialeurodes vaporariorum （Westwood） is a very important pest of greenhouse plants, but its resistance to pesticides has rendered it difficult to control by chemical methods in recent years. Sterile insect technique （SIT） is a biological control method which has been used in Area Wide Integrated Pest Management （AWIPM）. This study conducted the possibility of sterilising GHWF adults by gamma radiations emitted from cobalt 60. Longevity of the adults, and the amount of egg laying and sterilisation of eggs were determined under the influence of 50, 60, 70, 80, 90 Gy doses under controlled conditions （65 ± 5% RH, 25 ± 2 ℃, L/D = 16/8）. Normal insects were considered as control （0 dose）. The best combination for mating of normal and sterile adults （normal male × normal female as control, normal male and irradiated female, irradiated male × normal female, and irradiated male × irradiated female） was studied using a factorial design （n = 4）. Results showed that the best irradiating doses were 70 and 80 Gy for females and males respectively. Longevity of irradiated males and females was not significantly different from that of non-irradiated specimens. The best mating model was irradiated males and females.

Thermoluminiscence Response of an Alloy Quaternary Ionic Crystal Exposed to High Energy Radiation

The alkali halide crystals exhibit significant TL （thermoluminescence） properties when exposed to ionizing radiation. The defects in crystals can be produced in high concentration by means of chemical impurities, radiation, mechanical work and others processes. This study is concerned with the TL properties of quaternary mixtures of alkali halide crystals when they are irradiated with beta and gamma-rays. The samples were made mixing KCI, KBr, RbCI, RbBr salts doped with divalent europium （Eu2＋）, by the Czochralski method sintering at 400 ~C during 6 hours in a N2 atmosphere. The samples were exposed to beta and gamma rays. We present the TL glow curves, demonstrating that the nature of the defects in the crystals can be produced by trapping states and recombination mechanisms. The highest temperature TL curves are the most interesting due to possible applications in dosimetry and optical energy storage.

Study of latch-up immunization in bulk CMOS integrated circuits exposed to transient ionizing radiation

This paper presents experimental results of transient gamma irradiation effects on two kinds of circuits.One is a two-stage circuit consisting of a bipolar power device L7805CV and a bulk complementary metal-oxide-semiconductor(CMOS) device IDT6116,the other is a two-stage circuit consisting of a bipolar power device L7805CV and the equivalent circuit of the parasitic P-N-P-N structure in bulk CMOS devices.The results show that the L7805CV's output interruption after transient irradiation can prevent latch-up from occurring on the second stage circuit.The demanded minimum interruption duration to avoid latch-up varies with dose rate,and this is confirmed by the experimental results.

Effects of Gamma Irradiation for Sterilization on Aqueous Dispersions of Length Sorted Carbon Nanotubes

There is currently great interest in the potential use of carbon nanotubes as delivery vessels for nanotherapeutics and other medical applications. However, no data are available on the effects of sterilization methods on the properties of nanotube dispersions, the form in which most medical applications will be processed. Here we show the effects of gamma irradiation from a 60Co source on the dispersion and optical properties of single-wall carbon nanotubes in aqueous dispersion. Samples of different length-refined populations were sealed in ampoules and exposed to a dose of approximately 28 kGy, a level sufficient to ensure sterility of the dispersions. In contrast to literature results for solid-phase nanotube samples, the effects of gamma irradiation on the dispersion and optical properties of the nanotube samples were found to be minimal. Based on these results, gamma irradiation appears sufficiently non-destructive to be industrially useful for the sterilization of nanotube dispersions.