Systematic Control of the Excited‐State Dynamics and Carrier‐Transport Properties of Functionalized Benzo[ghi]perylene and Coronene Derivatives

A series of benzo[ghi]perylene (Bp) and coronene (Cor) derivatives substituted with electron‐withdrawing methoxycarbonyl (COOMe) or electron‐donating methoxyl (MeO) groups was synthesized. The electrochemical, spectroscopic, and photophysical properties of these compounds were investigated by cyclic voltammetry, steady‐state and time‐resolved spectroscopy, and quantum‐yield measurements. Introduction of suitable substituents onto the aromatic rings enabled control of electrochemical and spectroscopic behavior. Examination of excited‐state dynamics revealed that fluorescence quantum yields increased with increasing number of COOMe groups in both Bp and Cor derivatives, consistent with the findings of DFT calculations. Single‐crystal analysis allowed the performance of field‐effect transistors containing single crystals of the derivatives to be rationalized.     

Lactate biosensors: current status and outlook

Many research efforts over the last few decades have been devoted to sensing lactate as an important analytical target in clinical care, sport medicine, and food processing. Therefore, research in designing lactate sensors is no longer in its infancy and now is more directed toward viable sensors for direct applications. In this review, we provide an overview of the most immediate and relevant developments toward this end, and we discuss and assess common transduction approaches. Further, we critically describe the pros and cons of current commercial lactate sensors and envision how future sensing design may benefit from emerging new technologies.     

Ground states of Fermions on lattices

We consider Fermion systems on integer lattices. We establish the existence of dynamics for a class of long range interactions. The infinite volume ground states are considered. The equivalence of the variational principle and ground state conditions is proved for long range interactions. We also prove that any pure translationally invariant ground state of the gauge invariant algebra is extendible to a ground state of the full CAR algebra for the Hamiltonian with a chemical potential (equivalence of ensemble for canonical and ground canonical states at the zero temperature).     

On ground states of the one-dimensional ferromagnetic XXZ model

We obtain the complete list of pure infinite volume ground states for the one-dimensional ferromagnetic XXZ model.     

Hyperfine fields at Y nuclei in Y(Fe1−xTx)3 (T = Al, Co)

The spin echo spectra of ⁸⁹Y hyperfine fields in Y(Fe_1−xT_x)₃ with low concentration x consist of two main lines and of satellite lines caused by the replacement of the Fe atoms by the T atoms. Values of the magnetic moments of the T atoms are estimated by observing the satellite lines.     

Simultaneous determination of trace elements in minute samples by electrothermal-vaporization/low-pressure helium-ICP-MS.

Electrothermal vaporization with two filaments was studied for low-pressure helium-ICP-MS. A 10-microl volume of sample was dried and vaporized, and then introduced to the ICP. With this technique, four elements were simultaneously determined with the acceptable precisions (RSD ca. 10%). The detection limit based on 3sigma of background signals approached the fractional ppb range. The proposed method was successfully applied to the analysis of the certified reference material for human hair.     

Heat capacity of vanadium-oxygen alloy

Heat capacities of vanadium-oxygen alloys with various compositions, VO_0.0834, VO_0.1127, VO_0.1245, and VO_0.1296, were measured from 320 to 920K by adiabatic scanning calorimetry. A heat capacity anomaly due to order-disorder rearrangement of oxygen atoms was observed for all the compositions. The transition temperatures from α′ to β phase were found to be 780, 791, 786, and 768K for VO_0.0839, VO_0.1127, VO_0.1245, and VO_0.1296, respectively. The transition temperatures from β′ to β were also observed to be 665 and 660K for VO_0.1245 and VO_0.1296, respectively, but they shifted to lower temperatures in repeated measurements. The excess heat capacity due to order-disorder transition was obtained by assuming that the heat capacity can be expressed as the sum of a harmonic term of lattice vibration, a dilational term, an electronic term, and an anharmonic term of lattice vibration. The entropy changes due to the transition for VO_0.0834, VO_0.1127, VO_0.1245, VO_0.1296 were determined from the excess heat capacities to be 1.90, 2.88, 2.82, and 2.88 J K^?1 mole^?1, respectively, values which were explained by calculating the entropy changes due to the order-disorder rearrangement of oxygen atoms in the superstructures of VO_x alloys. From the O/V dependence of the transition temperature and entropy change, the most stable composition of the α′ phase was thought to be V₄₈O₅.     

Phase transition in Pd40Ni10Cu30P20 bulk metallic glass under HP & HT

The phase transitions in Pd₄₀Ni₁₀Cu₃₀P₂₀ bulk metallic glass (BMG) have been studied under high pressure and high temperature (HP & HT) by X-ray diffaction measurements with synchrotron radiation source. We found that the BMG underwent a phase transitions of amorphous-crystalline-amorphous at 10 GPa upon heating. The parallel experiments were carried out at 7 GPa, while we did not observe the amorphous-crystalline-amorphous transitions by increasing temperature. Quenching the melted BMG at 7 GPa, it was found that the phase crystallized from the melt differed from the primary phase crystallized from the starting amorphous solid upon heating suggesting there existed a distinct mechanism in two cases.     

Remarkable Dependence of the Final Charge Separation Efficiency on the Donor–Acceptor Interaction in Photoinduced Electron Transfer

The unprecedented dependence of final charge separation efficiency as a function of donor–acceptor interaction in covalently‐linked molecules with a rectilinear rigid oligo‐p‐xylene bridge has been observed. Optimization of the donor–acceptor electronic coupling remarkably inhibits the undesirable rapid decay of the singlet charge‐separated state to the ground state, yielding the final long‐lived, triplet charge‐separated state with circa 100 % efficiency. This finding is extremely useful for the rational design of artificial photosynthesis and organic photovoltaic cells toward efficient solar energy conversion.