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241.
何林生  柳尚青 《中国激光》1991,18(4):286-293
本文指出光场压缩态|α,z〉A=S(z)D(α)|0〉和|α,z〉B=D(α)S(z)|0〉不完全等价,它们实质上是本文命名的压缩子(Squeezon)湮灭算符b=SaS~+的两个本征态,具有完全相同的压缩特性,但本征值不同,光子统计分布和光子统计特性有显著差异,所含的能量状况亦很不相同。  相似文献   
242.
采用紫外线、同平板梯度浓度亚硝基肌,纯铜蒸气激光诱变去甲基金霉素生产菌金霉素链霉菌的原生质体,结果表明原生质体对各种诱变剂的敏感性较高.正变幅度较大.原生质体经紫外线、同平板梯度浓度亚硝墓肌复合诱变后,筛选到一菌株,重新制备原生体,经激光诱变,选育出高产菌株S. A. HU02,去甲基金霉素效价从2831u/ml提高到4337u/ml,提高了53. 2,经多次传代产量性状非常稳定.  相似文献   
243.
本文研究了在阴-非离子表面活性剂SDS-TritonX-100存在下,用Cadion 2B分光光度法测定银,发现DMF介质的增溶、增敏、增稳效果均好.配合物的最大吸收波长为560nm,表现摩尔吸光系数为1.23×10~5L·mol~(-1)·cm~(-1),Ag(Ⅰ)在0—18μg/25ml范围内服从比耳定律.该方法操作简便、快速,选择性好,可直接用于废水中微量银的测定,结果满意.  相似文献   
244.
对东乡野生稻的越冬性能进行了连续2年的观察,结果表明:东乡野生稻的稻蔸能在武汉地区安全越冬,翌年春季再生苗从地表以下的茎节长出.越冬再生植株与种子实生植株相比并无差异.  相似文献   
245.
Structures, heats of formation, and vibrational eigenvalues have been calculated by semiempirical AM 1 quantum mechanical method for the reactants, products, and activated complexes of three Mannich reactions, namely, the reaction between potential Mannich reagent H2N+ = CH2Cl? and furan and the conventional Mannich reactions between ammonia, formaldehyde, and furan in neutral and acidic media. It has been found that the Mannich reaction involving the potential Mannich reagent occurs more quickly than do the conventional Mannich reactions in neutral medium; the Mannich reaction in acidic medium proceeds most quickly. The results have been discussed in terms of the orbital match and static electric interaction between some atoms of reactant complexes. © 1995 John Wiley & Sons, Inc.  相似文献   
246.
247.
The photocatalytic activities of titanium dioxide (TiO2) supported on hexagonal mesoporous silica (HMS), zeolite Y (NaY) were investigated by using the photodegradation of 2,4,6-trichlorophenol (TCP) as test reactions. It was found that the photocatalytic activity of TiO2 on HMS was much higher than that of TiO2 powders, and that of TiO2 on NaY. It was also found that TiO2/HMS had maximal photocatalytic activity at a lower Ti content. The larger the pore size of HMS used as the support of TiO2, the better the photocatalytic activity of TiO2 for degradating of organic pollutant. These observations suggested that the supported structure was a main factor responsible for enhancement of the photocatalytic activity of TiO2. Characterization of the samples by TEM, XRD, BET, and UV-vis diffuse reflectance spectra indicated that the structures of HMS and TiO2 were confirmed and TiO2 did not enter into the HMS framework and was formed as nanoparticles on all supports.  相似文献   
248.
A seven‐step cascade reaction —in which selective mesylation, epoxide formation, epoxide lysis, cyclization, reiterative oxidation, and nitrogen–oxygen exchange occur sequentially—facilitates the construction of the maleic anhydride moiety of CP molecules 1 and 2 (>93% yield per step). Unstable intermediates of this reaction sequence were detected, providing evidence for the proposed mechanism and resulting in the discovery of a new chemical entity.  相似文献   
249.
One new tigliane-type diterpene, 4-deoxy-4(β)H-8-hydroperoxyphorbol-12-benzoate-13-isobutyrate (1), together with two known diterpenoids, 3-acetyl-5,8-dibenzoyl-14α-propanoyl-13,17-epoxy-7-myrsinaone diterpene with C9–C10 cyclised to form an additional lactone ring (2), Euphodendriane A (3) have been isolated from the whole plants of Euphorbia dracunculoides Lam. Their structures were elucidated by means of extensive spectroscopic analysis (NMR and HR-ESI-MS) and comparison with data reported in the literature. This is the first isolation of 8-hydroperoxy tigliane diterpene (1) from the genus of Euphorbia. All compounds were evaluated for their antifungal activities.  相似文献   
250.
In this study, the magnetic materials known as polymerized ionic liquid@3‐(trimethoxysilyl)propyl methacrylate@Fe3O4 nanoparticles were synthesized and utilized as potential adsorbents. First, these nanoparticles were applied to the analysis of sulfonamides and quinolones present in different water samples using magnetic solid phase extraction and high‐performance liquid chromatography. Under optimized conditions, the developed method showed excellent detection sensitivity, with limits of detection (S/N = 3) and quantification limits (S/N = 10) within 0.2–1.0 and 0.8–3.4 μg/L, respectively. The spiked recoveries of the SAs and QNs in environmental water samples ranged from 83.5 to 103.0%, with RSDs of less than 4.5%. In addition, the adsorbents effectively removed sulfamethoxazole and ofloxacin present in existing aquatic environments. The adsorption kinetics and isotherms of sulfamethoxazole and ofloxacin on the magnetic adsorbents were studied to assess removal performance. The results indicate that the adsorption process follows a pseudo‐second‐order mechanism, which reveals that the sorption mechanism is the rate‐limiting step and produces high qmax values (sulfamethoxazole = 70.35 mg/g and ofloxacin = 48.95 mg/g), thus demonstrating the enormous adsorption capacity of these magnetic adsorbents.  相似文献   
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