A time-compensated spectral filter for transform-limited tunable picosecond pulse generation from spectro-temporal-selection dye lasers

Diffraction and transform-limited picosecond tunable pulses are generated from Spectro-temporal-Selection (STS) dye lasers by using a new extra-cavity filter. This filter is based on a grazing-incident grating and arranged in the configuration of a folded dispersive delay line. Thus, it provides both high spectral selectivity and controllable temporal compensation for elimination of pulse broadening. Direct production of diffraction- and transform-limited picosecond dye laser (10 µJ, 50 ps) pulses spectrally adjustable between 398 and 702 nm is demonstrated in a compact device, with 8 ns pump pulses from a nanosecond nitrogen laser.     

Sloshing dynamics-modulated fluid angular momentum and moment fluctuations driven by orbital gravity gradient and jitter accelerations in microgravity

The dynamical behavior of spacecraft propellant affected by the asymmetric combined gravity gradient and jitter acceleration are studied. In particular the effect of surface tension on partially-filled rotating fluids applicable to a full-scale Gravity Probe-B Spacecraft dewar tank has been investigated. Three different cases of orbital accelerations: (a) gravity gradient-dominated, (b) equally weighted between gravity gradients and jitter, and (c) gravity jitter-dominated accelerations are considered. Fluctuations of angular momentum, fluid moment and bubble mass center caused by slosh wave excitations driven by gravity gradient and jitter accelerations are also investigated.     

Syntheses,Structures, and Magnetism of Trinuclear Zn2Ln Complexes with 2,6‐Dipicolinoylbis(N,N‐diethylthiourea)

The bifunctional ligand 2,6‐dipicolinoylbis(N,N‐diethylthiourea) (H₂L) readily reacts with mixtures of Zn(CH₃COO)₂ and LnCl₃ in MeOH at ambient temperature with formation of trinuclear heterobimetallic complexes [Zn₂Ln(L)₂(OAc)₃] ( 1a – 1f ) (Ln = Ce, Nd, Sm, Gd, Dy, Er). The X‐ray single‐crystal diffraction and structural studies of the complexes revealed their isostructural nature, in which two doubly‐charged ligands {L^2–} bind two Zn²⁺ ions with the terminal acylthiourea sites and one Ln³⁺ ion with the central 2,6‐pyridinedicarboxamide site. In the complexes, the coordination numbers of Ln^III and Zn^II ions are 9 and 5, respectively. Magnetic properties of the complexes were studied by temperature‐dependent dc magnetic measurements. The observed μ_eff values at room temperature are all closed to the calculated values. Fitting χ_M and M data of [Zn₂Gd(L)₂(OAc)₃] ( 1d ) shows a g_iso value of 1.94.     

Analysis of Calix[4]arenes Using Nonaqueous Capillary Electrophoresis

In nonaqueous capillary electrophoresis (NACE), an organic solvent is used in place of an aqueous medium as the background solution to improve the solubility and selectivity for hydrophobic analytes. In this study, we employed NACE with UV detection for the analysis of eight calix[4]arenes. We examined the influence of several parameters—the buffer composition, the nonaqueous solvent‘s composition and proportion, and the concentration of the electrolyte of the nonaqueous buffer—on the efficiency of the electrophoretic separation. The separation was achieved through the analyte's different effective mobility via different degrees of deprotonation on the phenolic OH groups of the calix[4]arene. This deprotonation can further affect the analyte's ability to form a complex with the metal ion. The optimized background electrolyte (BGE), comprising a mixture of N‐methylformamide/acetonitrile (30:70, v/v) and 100 mM AcOH/20 mM NH₄OAc, provided rapid (<11 min) separation of the calix[4]arenes with good resolution. The relative standard deviations of the migration times for the eight analytes were all less than 1%. Within the calibration concentration range, the coefficients of determination (R²) were all greater than 0.9914. Thus, the present study demonstrated NACE can provide adequate separation for the analysis of calix[4]arenes.     

Highly Efficient Dye‐Sensitized Solar Cells Based on Panchromatic Ruthenium Sensitizers with Quinolinylbipyridine Anchors

Panchromatic Ru^II sensitizers TF‐30–TF‐33 bearing a new class of 6‐quinolin‐8‐yl‐2,2′‐bipyridine anchor were synthesized and tested under AM1.5 G simulated solar irradiation. Their increased π conjugation relative to that of the traditional 2,2′:6′,2′′‐terpyridine‐based anchor led to a remarkable improvement in absorptivity across the whole UV–Vis–NIR spectral regime. Furthermore, the introduction of a bulky tert‐butyl substituent on the quinolinyl fragment not only led to an increase in the J_SC value owing to the suppression of dye aggregation, but remarkably also resulted in no loss in V_OC in comparison with the reference sensitizer containing a tricarboxyterpyridine anchor. The champion sensitizer in DSC devices was found to be TF‐32 with a performance of J_SC=19.2 mA cm^?2, V_OC=740 mV, FF=0.72, and η=10.19 %. This 6‐quinolin‐8‐yl‐2,2′‐bipyridine anchor thus serves as a prototype for the next generation of Ru^II sensitizers with any tridentate ancillary.     

Uniform Mesoporous Silica Hexagon and Its Two‐Dimensional Colloidal Crystal

Well‐ordered mesoporous silica nanoparticles with uniform hexagonal disk shapes are synthesized under dilute alkaline conditions with a two‐step process, separating the nucleation and growth process. The resulting monodisperse hexagons can be arranged in a 2‐dimensional (2D) ordered periodical super‐structure. The hexagonal symmetry is similar in both scales. A statistical mechanical cell model is applied to analyze consequences of the interesting packing structure, including osmotic bulk modulus, phase separation and defects.     

Sloshing dynamics modulated cryogenic helium fluids driven by gravity gradient or jitter accelerations associated with slew motion in microgravity

The mathematical formulation of the Dewar container sloshing dynamics for a partially filled liquid of cryogenic superfluid helium II driven by the gravity gradient or jitter accelerations associated with slew motion in a microgravity environment are studied. The numerical computation of sloshing dynamics is based on the non-inertia container bounded frame and the solution of time-dependent, three-dimensional partial differential equations subjected to the initial and boundary conditions. This study discloses that the capillary effect of sloshing dynamics governs the liquid-vapor interface fluctuations driven by the gravity gradient or jitter accelerations associated with slew motion in a microgravity environment. The peculiar behavior of superfluid helium in response to sloshing dynamics is also investigated.     

Reactions of Bis[Diphenyl‐3‐(4‐Methoxyphenylsydnonyl)]Phosphine Palladium Chloride and Phosphorus Ligands and Crystal Analysis of Its Phosphite Adduct

Reactions of bis[diphenyl‐3‐(4‐methoxyphenylsydnonyl)]phosphine palladium chloride and phosphines or phosphites were performed yielding cis‐dichloropalladium complexes. Complexes have been characterized by spectroscopic techniques (compounds 5–13 ) and by X‐ray diffraction for compound 5 . Bond lengths of P‐C(10) and P‐C(16) de creased more than that of P‐C(s) after complex formation suggesting that the phenyl rings were able to contribute more electron density to phosphorus for binding with Pd(II) than the sydnone ring does. The equilibrium constants and rate constants for the reaction between complex 4 and phosphorus ligands depend not only on the basicity but also on steric size (i.e., cone angle) of phosphorus ligands used.     

Photoassisted Synthesis of Luminescent Mannose–Au Nanodots for the Detection of Thyroglobulin in Serum

We have employed mannose‐modified gold nanodots (Man–Au NDs) as a luminescence sensor for the detection of the thyroid‐cancer marker thyroglobulin (Tg) in homogeneous solutions. The luminescent Man–Au NDs are prepared through the reaction of 2.9 nm‐diameter gold nanoparticles (Au NPs) with 11‐mercapto‐3,6,9‐trioxaundecyl‐α‐D ‐mannopyranoside (Man‐RSH) under the irradiation of a light‐emitting diode (LED). We have found that the irradiation enhances the quantum yield (～11 %), alters the emission wavelength and lifetimes, and shortens the preparation time. A luminescence assay has been developed for Tg based on the competition between Tg and Man–Au NDs for the interaction with the concanavalin A (Con A). Because luminescence quenching of the Man–Au NDs by Con A is inhibited by Tg selectivity, we have obtained a highly sensitive and selective assay for Tg.     

Syntheses,Structures, and Biological Activity of NiII,PdII, and PtII Complexes with New Tetradentate Benzamidine Ligands

N‐(Dialkylthiocarbamoyl)benzimidoyl chlorides react with o‐(salicylidenimine)benzylamine with formation of a novel class of tetradentate benzamidine ligands (H₂L^Et and H₂L^Morph), which readily react with Ni(CH₃COO)₂, [PdCl₂(CH₃CN)₂], and [PtCl₂(PPh₃)₂] under formation of complexes of the composition [M(L^R)] [M = Ni ( 4 ), Pd ( 5 ), Pt ( 6 )]. In all complexes, H₂L^R is doubly deprotonated and bonded to the metal ion via its N₂OS donor set and establishes a distorted square‐planar coordination sphere. The antiproliferative effects of the compounds on MCF‐7 and Hep‐G2 cells were studied. The complexes of H₂L^Morph are generally more active than those of H₂L^Et. While H₂L^Et and its complexes exhibit stronger effects on the Hep‐G2 line, the corresponding compounds of H₂L^Morph show almost equal effects on the two cell lines. In each series of compounds, the cytotoxicity increases in the order H₂L^R << 4 < 5 < 6 .