Recent Progress in Chemiluminescence for Gas Analysis

Abstract

Chemiluminescence is frequently used as a powerful analytical tool for gas analysis. In this mini-review with 102 references, we summarize the recent advances in chemiluminescence-based analytical methodologies and their application in gas/volatile species analysis, mainly including applications of ozone-induced chemiluminescence, cataluminescence-based gas sensors and arrays, and dielectric barrier discharge–induced chemiluminescence for gas analysis. Efforts in the innovation of the methodologies, the exploration of new sensing materials, and the mechanism studies are discussed in detail.     

The optimal harvesting policy for non-autonomous populations with discount

Infinite horizon and non-autonomous optimal harvesting problems with discounted instantaneous utility are considered in this work. We first show that the optimal harvesting policy exists for a class of single populations by using the maximum principle. Second, the explicit expressions for the optimal harvesting policy and the maximum yields of logistic, Gompertz and Gilpin–Ayahs systems are obtained.     

Finite p-groups with small subgroups generated by two conjugate elements

In this paper, we study the properties of a finite p-group G such that ${|\langle x, x^y \rangle:\langle x \rangle| \leq p}$ for all ${x,y \in G}$ . Such groups relate to a problem posed by Berkovich and Janko (Groups of prime order, Walter de Gruyter, Berlin, vol. 3, 2011) (Problem 1762). For such a group G, we mainly get the exponent of G′ and the nilpotent class of G.     

On Hypercentral Groups G With |G:G n |<∞

In 1960, Baumslag, following up on work of Cernikov for the 1940s, proved that a hypercentral p-group G with G = G ^p is a divisible Abelian group. In this article, we provide an interesting generalization of this 45 year old result: If a hypercentral p-group G satisfies |G:G ^p |<∞ (of course, it contains G = G ^p ), there exists a normal divisible Abelian subgroup D such that |G:D|<∞.     

Recoil proton tagged knockout reaction for He

We report for the first time the discrimination of the core fragment knockout and valence nucleon knockout reaction mechanisms at medium energy range, by the use of the recoil proton tagging technique. Intense ⁸He beams at 82.3 MeV/u were supplied by the RIPS beam line at RIKEN, and impinged on both hydrogen and carbon targets. Recoil protons were detected in coincidence with the forward moving core fragments and neutrons. The core fragment knockout mechanism is identified through the polar angle correlation and checked by various kinematics relations. This mechanism may be used to extract the cluster structure information of unstable nuclei. On the other hand, with the selection of the tagged valence nucleon knockout mechanism, a narrower peak of ⁷He ground state is obtained. The extracted neutron spectroscopic factor Sn=0.512(18) is relatively smaller than the no-tagged one, and is in good agreement with the prediction of ab initio Green?s function Monte Carlo calculations.     

A fluorescence chemosensor based on peptidase for detecting nickel(II) with high selectivity and high sensitivity

We report herein a new class of metal ion chemosensors and give the first example of a metal-dependent peptidase chemosensor for metal ions. The chemosensor contains the basic specific Ni(II)-dependent peptide bond hydrolysis sequence (Gly-Ala-Ser-Arg-His-Trp-Lys-Phe-Lys). The substrate was labeled with a fluorophore at the N-terminal and a quencher at the C-terminal Lys side chain. Initially, the MOCAc ((7-methoxycoumarin-4-yl)acetyl-) emission was quenched by the nearby quencher. In the presence of Ni(II), the substrate was irreversibly cleaved at the cleavage site, leading to a 20-fold increase in fluorescence intensity. The chemosensor combines the high selectivity of a peptidase (at least greater than tenfold for Ni(II) over other metal ions) with the high sensitivity of fluorescence detection limit of 50 nM and can be applied for the quantitative detection of Ni(II) over a concentration range of three orders of magnitude. Given this degree of selectivity and sensitivity, our molecular engineering design may prove useful in the future development of other peptidase-based probes for different metal ions in toxicological and environmental monitoring.     

Separation of peptides with an aqueous mobile phase by temperature-responsive chromatographic column (J. Sep. Science 35'16)

DOI: 10.1002/jssc.201200247 A thermoresponsive chromatographic material was prepared through a simple method and employed for the temperature-modulated separation of peptides in an aqueous mobile phase. At 10°C, the grafted polymer chains are hydrophilic and in the form of extended coil. In this case, the peptides were unable to be separated and showed a single peak in chromatograms. In contrast, the polymer is hydrophobic and in the form of collapsed globule at 50°C. In this case, the peptides were completely separated because of the enhanced hydrophobic interaction of peptides and stationary phase.     

Self-assembly of highly uniform LiFePO4 hierarchical nanostructures by surfactant molecules in a new mixture medium

In this work, the LiFePO₄ samples are synthesized in ethylene glycol/water (EG/W) and aqueous solution, respectively. The samples are characterized by X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy, electron diffraction, and nitrogen adsorption isotherms. The results show that the reaction medium and the surfactant molecules have the significant influences on the particle morphology. In the presence of dodecylbenzenesulfonic acid sodium, the highly uniform LiFePO₄ hierarchical nanostructures are obtained in EG/W, which consist of the nanoplates. Nevertheless, the irregular LiFePO₄ microparticles are obtained in aqueous solution. Furthermore, the electrochemical properties of the samples are mainly investigated. The hierarchical LiFePO₄ sample exhibits a higher rate capability and an improved cyclability than the aggregated irregular microparticles, which have been ascribed to the highly uniform hierarchical nanostructures.     

Rapid organism degradation function of Fe-based alloys in high concentration wastewater

The treatment of high concentration organic wastewater using Fe-based alloys in the Fenton-like system was investigated. The removal rate of COD by using the Fe₇₈Si₉B₁₃ metallic glass (MG) reached 85%, about 30% and 40% higher than that by the Fe₇₈Si₉B₁₃ crystalline alloy (CA) and by the traditional material Fe⁰ used in Fenton-like system, respectively. The treatment result by the Fe₇₈Si₉B₁₃ MG was more than 65% higher and 50 times faster than that of the traditional aeration process with the same addition of Fe⁰. It has been proved that the Fe₇₈Si₉B₁₃ MG played an excellent catalytic activity in the oxidative degradation of organic compounds, and its microstructure transformation during the corrosion process promoted the degradation efficiency of the wastewater treatment process.     

Synthesis,Crystal Structure,Magnetic Properties of a Manganese(II) Coordination Polymer with Double-Helix Chains

Abstract  

A new heterocyclic carboxylate ligand, 5-(4′-pyridyl)-3-methyl-benzoic acid (Hpmba), was synthesized to construct a Mn(II) coordination polymer, namely [Mn(pmba)₂] _n (1). Complex 1 crystallizes in monoclinic space group C2/c, with a = 17.44(2), b = 17.040(12), c = 8.680(15) ?, β = 111.258(13), V = 2404(5) ?³, and Z = 4. Single-crystal X-ray diffraction studies show that complex 1 has a 3D metal-organic supramolecular framework consisting of double helical chains. Magnetic studies for complex 1 show antiferromagnetic coupling between the nearest Mn(II) ions, with g = 2.11 and J = −10.1 cm⁻¹.