Effect of light irradiation

The Sjjf.fl character of the reaction was ascertained by the effect of light irradiation and addition of a radical trap. Namely, under light irradiation, the half-reaction time was considerably shortened (3 instead of 41 min). Addition of di(tert-butyl)nitroxide completely quenched the reaction—neither C- nor 0-substitution was observed after 4 h. The radical trap may only react with the R radicals that escaped the solvent cage where R, Nu, and X have been formed. This means that, in the... 

Fig. 37. Band edge profile of a (In,Mn)As/GaSb heterostmcture. Eq. E. and Ep denote band edges of conduction band, valence band, and Fermi level, respectively, (b) Temperature dependence of the magnetization observed during cooldown in the dark (open circles) and warmup (solid circles) under a fixed magnetic field of 0.02 T. The effect of light irradiation at 5 K is also shown by an arrow, (c) Magnetization curves at 5 K observed before (open circles) and after (solid circles) light irradiation. Solid line shows a theoretical curve, (d) Hall resistivity />Hall observed at 5 K before (dashed line) and after (solid line) light irradiation (Koshihara...

As illustrated in Fig. 1, these processes may be initiated by the absorption of light by the adsorbate (A), the substrate (S) or adducts (A-S) originating from their interaction. Excitation on the adsorbate or the adduct may relax following a reaction pathway in which the bulk solid may either participate actively or remain inactive. Otherwise, the substrate itself could become excited and trigger a reaction within the adsorbate [5]. In order to understand the diverse photochemistry undergone by an adsorbed molecule, it is convenient to analyze the effect of light irradiation on semiconductors, metals and insulators. 

The effects of light irradiation on the content of total lycopene and d.v-isomer in tomato puree are shown in Figures 4.9 and 4.10. The increase in civ-isomers began to occur at the onset of exposure to light. Total lycopene loss as well as d.v-isomer loss increased with light irradiation time. 

FI G U RE 4.9 The effect of light irradiation on total lycopene degradation (Shi and Le Maguer, 1999b). 

Figure 2. Effect of light irradiation time on the luminol release from II. [II] = 1 pmol/L, [NaOH] = 10 mmol/L, [H2O2] = 500 mmol/L.

To ascertain that the photo-generated paramagnetic center in poly(carbon suboxide) is indeed identical to that originally present in the polymer, the effect of light irradiation on the ESR spectrum of 13c-labelled polymer was examined. The ESR spectrum of poly(carbon suboxide) with natural abundance of is a strong singlet absorption with very weak 13c satellite lines... 

Zhong, J.J., Seki, M., Furusaki, S., and Furaya, T. 1991. Effect of light irradiation on anthocyanin production by suspended cultures of Perilla frutescens. Biotech. Bioeng. 36, 653-658. 

An important feature of the effect of light irradiation is the absence of any fatigue based on the spin-crossover phenomenon. The authors have concluded that the general modification of the intermolecular interaction topology mainly consists of variations of the sulfur-carbon distances during irradiation. They consider this observation as relevant information for a general study of photo-excited states in future attempts to design materials for electric molecular devices. 

Licht-echtheit, /. fastness to light, -effekt, m. luminoiis effect, -eindruck, m. luminous impression. -einstrahlung, /. irradiation (by light), -elnwirkung, /. action or effect of light. 

The effects of UV irradiation to enhance the degradation of aged Pu(IV) polymer in HClOi. Depolymerization under dark conditions for each experiment is shown by a data point directly above the last light sample point (4). 

Fig. 7. Effect of light on the IC50 values for the inhibition of cell growth of various cancer cell lines by platinum(IV) diazido complexes, (a) toxicity of the cis-complexes 4 and 5 on human bladder cancer cell lines (5637-CDDP, cisplatin-resistant cell line) (b) comparison of cytotoxicities of the cis- and rarcs-isomers 4 and 6 in the dark and upon irradiation cisplatin is included for comparison. Data from Ref. (30).

Glucose, glycerol, sucrose, starch, acetate, malate and lactate were examined for the effect of carbon sources on the hydrogen production and the effects of light intensity were also examined under the different irradiances, such as 0, 3, 7, 15, 30, 50 and 110 klux/m2, by adjusting the distance between the light source and the samples of Rb. sphaeriodes KD 131 cultures. 

By contrast, a reference sample is a test assembly using the rubber under test but which is protected from light during any irradiation exposure period and is, hence, used to distinguish between the effects of light and heat. 

Liquid water was decomposed to Ti2 ana 02 stoicniometrical y and continuously by sonopiiutocaialytic reaction, as shown Fig. 12.2. Effectiveness of simultaneous irradiation of ultrasound and light is also confirmed as shown in Table 12.1. This table shows the gaseous reaction products froir liquid water in... 

One curious case of the effect of light on electron-transfer equilibrium involves the reduction of ,p-di(t-butyl)stilbcnc with potassium in DME. The reaction leads directly to a diamagnetic dianion a solution of this dianion remains ESR silent unless subjected to ultraviolet irradiation by a Hg/Xe lamp. The anion radical of a,(3-di(t-butyl)stilbene then formed from the dianion by the loss of an electron. The electron reverted within 5-10 min after ultraviolet irradiation was turned off, transforming the anion radical into the dianion (Gerson et al. 1996). This case deserves to be clarified. Maybe the light effect consists simply in singlet-triplet transformation of the dianion, with the formation of some more or less stable biradical state of the dianion, which possesses two unpaired electrons and can even be a paramagnetic one. 

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