Administrative reform and the disposal of zombie enterprises: evidence from China.

The study investigates the effects of drastic institutional changes on the reduction of zombie enterprises in China and the underlying mechanisms of this relationship. We employed data from the ASIF from 1998 to 2007 and adapted the difference-in-difference approach to analyze the effects based on China's investment approval system reform. We find that the reform can reduce the proportion of zombie enterprises by 13.3%. This result is driven by competition and scale effects. The former reduces institutional transaction costs by 12.8% and increases innovation capacity by 6.1%. The latter significantly improves the total factor productivity of enterprises; the reform promoted the expansion of enterprise size by 7.1% and the enhancement of market accommodation capacity by 13.2%. The reform had a weak effect on state-owned and non-competitive industrial zombie enterprises. This paper contributes to debates concerning the effect of institutions on entrepreneurship and the disposal of small zombie enterprises.

Application of aromatic amide-derived atropisomers as chiral solvating agents for discrimination of optically active mandelic acid derivatives in 1 H nuclear magnetic resonance spectroscopy.

Non-biaryl atropisomers and their stereochemistry have attracted much attentions in the past years. However, application of the non-biaryl atropisomers as chiral solvating agents is yet to be explored. In this work, four aromatic amide-derived atropisomeric phosphine ligands (hosts) were used as chiral solvating agents to recognize various mandelic acid derivatives (guests) in 1 H nuclear magnetic resonance (NMR) spectroscopy. It is found that chiral center configurations of the four hosts have different effects on the enantiorecognition to the used guests. In addition, the host and guest interaction was further investigated by determination of the host-guest complex stoichiometry using the Job's method and density functional theory calculation, respectively. Moreover, chiral analysis accuracy of these hosts was evaluated through relationship between enantiomeric excess values of 4-chloromandelic acid provided by NMR and gravimetry, respectively.

Methoxy terminated poly dimethylsiloxane bonded stationary phase for reversed-phase liquid chromatography.

In this work, a methoxy terminated poly dimethylsiloxane modified silica gel material was proposed as a novel stationary phase for reversed-phase liquid chromatography. With 5 µm silica gel as matrix, methoxy terminated poly dimethylsiloxane polymer was grafted by one step chemical bonding reaction. The obtained stationary phase was characterized by scanning electron microscopy, fourier transform infrared spectroscopy and element analysis. To our knowledge, this is the novel methoxy terminated poly dimethylsiloxane bonded stationary phase with good separation efficiency (42107-46988 plates/m for benzene homologues) and high stability (RSD is 0.08-5.09%). Comparing to other traditional columns of the same type, the proposed stationary phase has a wider polarity separation scale and shorter analysis time. In addition to the rapid separation of hydrophobic compound, such column also exhibited great potential in the separation of hydrophilic analytes.

Preparation and chromatographic evaluation of the hydrophilic interaction chromatography stationary phase based on nucleosides or nucleotides.

In this work, a series of novel hydrophilic interaction chromatography (HILIC) stationary phases were prepared by grafting nucleosides or nucleotides on the surface of silica gel. Firstly, the silica was modified with 3-glycidoxypropyltrimethoxysilane (GPTMS). And then nucleosides or nucleotides were bonded on the surface of GPTMS-modified silica through the epoxy-amine ring-opening reaction to provide four HILIC materials. These obtained stationary phases were successfully characterized by Fourier transform-infrared spectroscopy (FT-IR) and elemental analysis (EA), respectively. Effects of column temperature, water content of the mobile phase, pH and buffer concentration on the retention behavior of these HILIC materials and the corresponding separation mechanism were evaluated using various nucleosides and nucleobases, respectively. In addition, polar and hydrophilic compounds such as amino acids and water-soluble vitamins were successfully separated using the corresponding columns, showing application potential for the separation of bioactive substances.