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The spin-correlated radical pairs (SCRPs) formed by photoinduced electron transfer from zinc tetrakis(4-sulfonatophenyl)porphyrin (ZnTPPS) to quinones in micelles of the cationic surfactant cetyltrimethylammonium chloride (CTAC) were studied by means of Fourier transform EPR (FT-EPR). It is shown that variation of the power of the microwave pulse allows the separation of EPR signals arising from SCRPs and free radicals. The measured kinetics of radical formation can be accounted for in terms of a statistical model taking into account the non-uniform distribution of the solutes over the micelles. The rate constant of electron transfer quenching (k_q) of the ZnTPPS triplet state by duroquinone (DQ) is found to be 1.05 × 10⁶ s⁻¹. The FT-EPR measurements gave information also on the kinetics of the homogeneous electron transfer reaction DQ⁻ + DQ → DQ + DQ⁻ in CTAC solution in which the DQ⁻ anion radicals were generated by light-induced electron transfer from ZnTPPS. It is found that the dependence of the rate of this reaction on quinone concentration deviates from the linear relationship found in homogeneous solutions. A statistical model is proposed to account for the data. Based on this model, the rate constant of the self-exchange reaction (k_ex) is 4.1 × 10⁶ s⁻¹. From results obtained with duroquinone and benzoquinone as acceptors, it is concluded that ZnTPPS is located at the micelle/water interface.

A comprehensive SPICE model is developed for single photon avalanche diodes (SPADs). The model simulates both the static and dynamic behaviors of SPADs. Parameters of the model were extracted form experimental data obtained from SPADs designed and fabricated in a standard 0.5μm CMOS process. In this model, the resistive behavior of the device was modeled with an exponential function. Moreover, the device simulated response to incident optical power stimulation is modeled. Experimentally extracted parameters were incorporated into the model, and simulation results agreed with the experimental data.

We investigate the thermal quench of Ising and Potts models via Monte Carlo dynamics. We find that the local distribution of the site-site interaction energy has the same form as in the equilibrium case, a result that allows us to define an instantaneous temperature θ during the systems relaxation. We also find that, after an undercritical quench, θ equals the heat bath temperature in a finite time, while the total system energy is still decreasing due to the coarsening process.

In this document I present a brief review of the concepts of jet physics employed in heavy ion physics. Fast partons originating from scatterings with large momentum transfer are produced at very short time-scales and subsequently propagate through the strongly interacting medium produced in the collisions of heavy nuclei. They feature the only experimental handle available to directly study the interaction of a well defined probe and the medium. Consequently they are ideally suited to investigate the nature of the medium produced in these collisions and the mechanism of interaction between the medium and the partons. The experimental methods necessary to reconstruct jets originating from fragmenting partons in the environment of high particle multiplicity heavy ion collisions will be discussed. Physics observables suited to investigate the parton medium interaction will be introduced and a summary of recent results on jet physics in heavy ion collisions is presented.

Interaction among different units in a network of oscillators may often lead to quenching of oscillations and the importance of oscillation quenching can be found in controlling the dynamics of many real world systems. But there are also many real life phenomena where suppression of oscillation should be avoided for maintaining the sustained evolution of the system. In this work, we propose a self-feedback control scheme through which one is able to either achieve quenching or to retrieve the rhythmic behavior in a network of mean-field diffusively coupled systems. It is found that for proper choice of the strength of the control signal, the system converges to an oscillatory state from oscillation quenched state and for further increase of the strength the system enters in chaotic region. Moreover, reversal of the phase of the control signal can induce suppression of oscillation. Thus, the proposed modification offers a better control on the dynamics of the mean-field coupled system. In addition to this, a new transition phenomenon from inhomogeneous limit cycle (IHLC) to homogeneous limit cycle (HLC) through chaotic route has also been found in the modified system.

The photophysical and photochemical properties and quenching (by 1,4-benzoquinone) of metallophthalocyanine sulfonates of aluminium (AlPcS_mix), zinc (ZnPcS_mix), silicon (SiPcS_mix), germanium (GePcS_mix) and tin (SnPcS_mix) are presented. The quantum yield values of fluorescence (Φ_F), triplet state (Φ_T), singlet oxygen (Φ_Δ) and photodegradation (Φ_d) were determined and the observed trends in their variation among the complexes discussed in terms of aggregation and the heavy atom effect. 1,4-benzoquinone effectively quenched the fluorescence of the complexes. Quenching analyses gave positive deviations from Stern-Volmer behavior, suggesting the existence of static quenching in addition to dynamic quenching. The static and dynamic components of the quenching were separated using a modified Stern-Volmer equation and the “sphere of action quenching model”. The quenching constant was found to be a function of the radius of the central metal ion.

The synthesis, spectral and photophysical properties including fluorescence quenching of the following octa-substituted oxotitanium phthalocyanines are reported: 2,3,9,10,16,17,23,24-octaphenoxyphthalocyaninato titanium(IV) oxide, 2,3,9,10,16,17,23,24-[octakis(4-t-butylphenoxyphthalocyaninato)]titanium(IV) oxide, 2,3,9,10,16,17,23,24-{octakis[(4-benzyloxy)phenoxy]phthalocyaninato}titanium(IV) oxide and 2,3,9,10,16,17,23,24-octaphenylthiophthalocyaninato titanium(IV) oxide. The complexes are characterized by ¹H NMR, IR and UV-vis spectroscopies. Their photophysical properties are presented where moderate fluorescence quantum yields (0.14-0.19) and lifetimes were determined. Varied triplet quantum yields were obtained and the triplet lifetimes (40-100 μs) were short.

Oxygen-monitoring techniques are applied to various fields, such as chemicals, deep sea environment, fluid dynamics, clinical analysis and environmental monitoring. Recently, a variety of devices and sensors based on phosphorescence or photoexcited state quenching of porphyrin molecules have been developed to measure oxygen concentration on the solid surface. Many optical oxygen sensors are composed of porphyrins (platinum(II), palladium(II), zinc(II), metal-free, etc.) dispersed in oxygen-permeable polymer film or directly immobilized onto solid surface via chemical or physical adsorption. Oxygen-sensing systems are classified into four types: (1) phosphorescence intensity change, (2) phosphorescence lifetime change, (3) change of lifetime of photoexcited triplet state, and (4) intensity change of absorption of photoexcited triplet state. In this review, the properties of various optical oxygen-sensing devices using porphyrins and sensing system are introduced.

Monomeric and Si–Si bonded dimeric silicon(IV) phthalocyanines bearing 4${}^{\prime }$,7${}^{\prime }$,10${}^{\prime }$-trioxaundecylsulfanyl groups were synthesized. These novel phthalocyanine derivatives were characterized by general analysis methods such as FT-IR, MALDI-TOF or HRMS, ¹H NMR and UV-vis electronic absorption. Their aggregation behaviors were described in dimethyl sulfoxide (DMSO). In addition, the photophysical and photochemical properties of these phthalocyanines were also investigated in DMSO to determine potential of these phthalocyanines to acts as photosensitizer for photodynamic therapy (PDT) of cancer. Their high singlet oxygen generation demonstrated their suitability for PDT applications. These peripherally 4${}^{\prime }$,7${}^{\prime }$,10${}^{\prime }$-trioxaundecylsulfanyl substituted silicon(IV) phthalocyanines are promising Type II photosensitizers owing to their favorable singlet oxygen generation capability. In addition, their fluorescence quenching behavior by 1,4-benzoquinone were also studied in DMSO.

The oleate capped NaYF₄:Yb/Er upconversion nanoparticles (OA-UCNPs) were firstly synthesized by the thermal decomposition method and subsequently converted to water-dispersible, ligand-free UCNPs (LF-UCNPs) via an easy acid treatment process. The interaction of LF-UCNPs with bovine serum albumin (BSA) was then investigated. The binding of LF-UCNPs with BSA was confirmed by the static quenching of intrinsic fluorescence of BSA upon addition of LF-UCNPs. The spectra of synchronous fluorescence and circular dichroism (CD) of BSA in the absence and presence of LF-UCNPs revealed that the presence of LF-UCNPs led to a slight conformational change of BSA, suggesting a minor nanotoxicity of LF-UCNPs toward BSA.

In this paper, a novel fluorescent nanoswitch based on carbon dots (CDs) was developed for the sensitive and selective determination of Hg${}^{2+}$ and I${}^{-}$. The CDs were obtained by simple hydrothermal process and had a strong fluorescence emission at 440nm. The fluorescence of the CDs can be selectively quenched by Hg${}^{2+}$ ion, and then the I${}^{-}$ was added into the system, which can interact with Hg${}^{2+}$ and recover fluorescence of the CDs. Under optimal conditions, the quenching fluorescence intensity on addition of Hg${}^{2+}$ has obtained a satisfactory linear relationship covering the linear range of 0–50$\mu$M with the linear relationship ($R_1^2=0.9991$), and the limit of detection is 0.047$\mu$M. The additions of I${}^{-}$ could lead to the fluorescence intensity of the solution of CDs and Hg${}^{2+}$ (50$\mu$M) recover rapidly, which is linearly related ($R_2^2=0.9957$) to the concentration of I${}^{-}$ in the range from 0 to 70$\mu$M, the detection limit for I${}^{-}$ was calculated to be 0.084$\mu$M. Moreover, the developed method to detect Hg${}^{2+}$ and I${}^{-}$ was evaluated in real examples, and the fluorescence switching can sensitively and selectively detect Hg${}^{2+}$ and I${}^{-}$ over some potentially interfering ions, the recoveries were up to 97.8–107.0% and 96.7–106.6%, respectively.

Quenching is commonly used for improving material properties of steel tubes because of their numerous applications. However, quenching generates some residual stress and deformation in the material due to rapid temperature fluctuations. The properties of the steel are strong functions of these variable temperatures and therefore, the estimated stress and deformation by constant property or static quenching analysis are not very realistic. This study describes the first extensive study of the quenching process of a steel tube including temperature dependent properties by three liquid quenchants using the dynamic fluid–structure interaction quench model. The cooling characteristics of the three liquid quenchants are compared to each other along with the transient temperature distributions in the steel tube. The time-varying nodal, axial, and radial residual stress and deformation of the tube are studied. It is found that, the effectiveness of quenching does not depend only on a particular quenchant, but also on the temperature-varying properties of the steel and the uniformity of the cooling which ultimately determine the criteria for selecting a suitable quenchant for a specific purpose.

In order to enhance the hot-quenching steel's comprehensive performance, a C-Si-Mn-Ti-B hot forming steel is designed. By the means of experiment, WHF1300R/D steel's micro metallographic structure and mechanical performance in the procedures of hot rolling, annealing and hot stamping is studied and it performs good hardenability. Through the hot forming technic experiment, the most appropriate cooling velocity is found, which inhibits the formation of pearlite and bainite effectively. The microstructure of the hot-stamped WHF1300R/D steel sheet is composed of lath martensite. The strength and ductility of the hot-stamped WHF1300R/D steel sheet are matched well with a tensile strength of about 1300MPa and a total elongation up to 12%.