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31.
The boxes contained kiwifruits were irradiated with cobalt-60 γ-rays at different dosages (0.6 , 1.8 and 3.6 KGy) and stored in a room ventilated at night, the natural ambient air being used as cool source.The results showed that the treatment which fruits irradiated with 0.6 KGy was the best after 85 days. It gave the normal-fruit rate of 95.10%, fruit flesh hardness of 4.10 Kg · cm-2, fresh and plump fruits, good quality and less Vc loss. 相似文献
32.
Poly(n-vinylpyrrolidone) hydrogels: 2.Hydrogel composites as wound dressing for tropical environment
POLY(N-VINYLPYRROLIDONE) HYDROGELS: 2. HYDROGEL COMPOSITES AS WOUND DRESSING FOR TROPICAL ENVIRONMENT. The effects of irradiation on hydration and other properties of poly(vinylpyrrolidone) (PVP) hydrogel composites have been investigated. The aqueous solution of vinylpyrrolidone (VP) 10 wt % was mixed with several additives such as agar and polyethylen glycol (PEG). The solution was then irradiated with gamma rays from Cobalt-60 source at room temperature. Several parameters such as elongation at break (EB), tensile strength (TS), degree of swelling (DS), water vapor transmission rate (WVTR), equilibrium water content (EWC), microbial growth and penetration test, and water activity (Aw) were analysed at room temperature of 29 ±2°C humidity of 80 ± 10%. Results show that elongation at break of hydrogel membranes with initial composition of VP with agar, VP with agar and PEG were 240 % and 250 % kGy, the equilibrium water content of membranes were 96 to 90%, whereas degree of swelling were 55 to 10. The WVTR of hydrogel membranes with initial composition of VP with agar and PEG was 70 g m-2h-1, while the water activity was 0.9. Such hydrogel membranes exhibits the following properties: They are elastic, transparent, flexible, impermeable for bacteria. They absopt a high capacity of water, attached to healthy skin but not to the wound and they are easy to remove. These properties of the hydrogel membranes allow for applying as a wound dressings in tropical environment. 相似文献
33.
Rahman Hosseinzadeh Ali Sharifi Kourosh Tabar-Heydar Farshid Mohsenzadeh 《Monatshefte für Chemie / Chemical Monthly》2002,133(11):1413-1415
Summary. N,N-Dimethylhydrazones of ketones and aldehydes undergo facile cleavage to the corresponding carbonyl compounds upon exposure
to microwaves in water containing a catalytic amount of PdCl2–SnCl2 in high yields.
Corresponding authors. E-mail: rahman@umz.ac.ir
Received December 27, 2001. Accepted (revised) February 6, 2002 相似文献
34.
35.
This Letter describes the amination of 3-bromoisoxazoles by a nucleophilic aromatic substitution reaction. We have found 3-bromoisoxazoles to be inert to substitution under thermal conditions, however, the employment of phosphazene bases under microwave irradiation facilitates the amination process and allows the corresponding 3-aminoisoxazoles to be isolated in moderate yield. 相似文献
36.
Spiro [3H-indole-3,2′-[4H] pyrido [3,2-e]-1,3-thiazine]-2,4′ (1H) diones, a class of previously unknown compound which does not form under conventional conditions, can be prepared by treatment of ‘in situ’ generated 3-indolylimine derivatives with 2-mercaptonicotinic acid under microwave irradiation in absence of any solvent or solid support in 85-92% yields in 3-8 min. The facile one pot reaction is generalized for a variety of ketones and amines to give pure pyrido [3,2-e] thiazine derivatives, which do not require further purification processes. 相似文献
37.
微波作用下2,5-二取代-1,3,4-噁二唑的合成 总被引:2,自引:0,他引:2
2 ,5 二取代 1 ,3 ,4 二唑可用作药品 ,光敏物质 ,闪烁体 ,激光材料 ,高分子液晶单体等[1- 5] 。一种是以芳香酸与水合肼作为原料用多聚磷酸作为脱水环合剂来合成此类化合物[6 ] ,另一种是由芳香酸转变为芳香酰氯或酯 ,再与水合肼反应得到单酰肼或二酰肼 ,最后用三氯氧磷[7] ,五氧化二磷和五氯化磷[8] ,一氯三甲硅[9] 脱水环合 ;此外 ,用水合肼和尿素合成得到的氨基脲代替水合肼 ,与芳香酸缩合合成二唑[10 ] ,这些方法共同的缺陷是 :环合时间较长 ,少者 4~ 5h ,多则 8h。近年来 ,微波技术在有机合成及其杂环化合物的合成中得到了广… 相似文献
38.
We synthesized the new photosensitive oligomer containing a chalcone moiety in the main chain by end-capping reaction of diepoxide compound with methacrylic acid. The chalcone-epoxy oligomeric compound was synthesized with 4,4′-dihydroxychalcone and epichlorohydrin. Investigation of the photosensitivity of the newly synthesized chalcone oligomer was carried out by using UV-Vis absorption and infrared spectroscopies under UV exposure. We observed the photodimerization behavior under UV irradiation. At the same time, we could also observe the photopolymerization of the compound with a trace amount of dimethoxyphenyl acetophenone. Thermal properties of UV-cured dimethacrylate compounds were also studied. 相似文献
39.
The applicability of the epr technique for the detection of dried vegetables, mushrooms, some spices, flavour additives and some condiments preserved with ionizing radiation is discussed. The epr signals recorded after exposure to gamma rays and to beams of 10 MeV electrons from linac are stable, intense and specific enough as compared with those observed with nonirradiated samples and could be used for the detection of irradiation. However, stability of radiation induced epr signals produced in these foods depends on storage condition.
No differences in shapes (spectral parameters) and intensities of the epr spectra recorded with samples exposed to the same doses of gamma rays (60Co) and 10 MeV electrons were observed 相似文献
40.
与氯代烯烃或芳烃相反, 氯代膦烯与零价钯的氧化加成反应可以在温和条件下进行. 提出了可能的反应机理. 起始卤代膦烯的结构决定了反应历程和最终产物的结构. 相似文献