Through research on official and semi-official Chinese documents, this article has found evidence to support the argument that there was a military coup d'etat taking place during the 1989 Tiananmen ...crisis. This invalidates a long-held assumption that a coup has been absent in the history of the People's Republic of China. As the military leader, Deng Xiaoping played a central role in the coup, and the coup served as a political prelude to the later military crackdown on Tiananmen prodemocracy demonstrators. The coup was prepared during the days following April 26 when Deng announced his hardline stance against Tiananmen pro-democracy demonstrations through the mouthpiece of the Chinese Communist Party (CCP), took place at the meeting illegitimately summoned by Deng at his residence on May 17, which enacted martial law and dismissed Zhao Ziyang, the top civilian leader, and was completed at the another meeting also held at Deng's residence on May 19 by Deng's anointment of the new party chief Jiang Zemin. In a comparative context of the Global South, the article further analyzes the case of a coup for highlighting its three "Chinese characteristics", which are: the structural inherency of the military power in PRC politics; the operational furtivity for political considerations; and the interweaving between the military mobilization for the purpose of illegitimate leadership and that for the purpose of suppressing social movements. These features may obscure relevant observations, but are not in conflict with a common definition of the coup. Instead, they can enrich the understanding of the coup. In essence, the Tiananmen Chinese coup is a response with the employment of state violence against the Chinese momentum of democratic transition.
In crowded fluids, polymer segments can exhibit anomalous subdiffusion due to the viscoelasticity of the surrounding environment. Previous single-particle tracking experiments revealed that such ...anomalous diffusion in complex fluids (e.g., in bacterial cytoplasm) can be described by fractional Brownian motion (fBm). To investigate how the viscoelastic media affects the diffusive behaviors of polymer segments without resolving single crowders, we developed a novel fractional Brownian dynamics method to simulate the dynamics of polymers under confinement. In this work, instead of using Gaussian random numbers ("white Gaussian noise") to model the Brownian force as in the standard Brownian dynamics simulations, we introduce fractional Gaussian noise (fGn) in our homemade fractional Brownian dynamics simulation code to investigate the anomalous diffusion of polymer segments by using a simple "bottle-brush"-type polymer model. The experimental results of the velocity autocorrelation function and the exponent that characterizes the subdiffusion of the confined polymer segments can be reproduced by this simple polymer model in combination with fractional Gaussian noise (fGn), which mimics the viscoelastic media.
A new green-emitting fluorescent probe
was developed for biothiol detection. The sensing mechanism was considered to be biothiol-induced cleavage of the 2,4-dinitrobenzene- sulfonate group in probe
...and resulting inhibition of the probe's photoinduced electron transfer (PET) process. Probe
exhibited favorable properties such as excellent selectivity, highly sensitive (0.12 µM), large Stokes shift (117 nm) and a remarkable turn-on fluorescence signal (148-fold). Furthermore, confocal fluorescence imaging indicated that probe
was membrane-permeable and suitable for visualization of biothiols in living A549 cells.
In this manuscript, we use a combination of Car-Parrinello molecular dynamics (CPMD) and ReaxFF reactive molecular dynamics (ReaxFF-MD) simulations to study the brown coal-water interactions and coal ...oxidation. Our Car-Parrinello molecular dynamics simulation results reveal that hydrogen bonds dominate the water adsorption process, and oxygen-containing functional groups such as carboxyl play an important role in the interaction between brown coal and water. The discrepancy in hydrogen bonds formation between our simulation results by ab initio molecular dynamics (CPMD) and that by ReaxFF-MD indicates that the ReaxFF force field is not capable of accurately describing the diffusive behaviors of water on lignite at low temperatures. The oxidations of brown coal for both fuel rich and fuel lean conditions at various temperatures were investigated using ReaxFF-MD simulations through which the generation rates of major products were obtained. In addition, it was observed that the density decrease significantly enhances the generation of gaseous products due to the entropy gain by reducing system density. Although the ReaxFF-MD simulation of complete coal combustion process is limited to high temperatures, the combined CPMD and ReaxFF-MD simulations allow us to examine the correlation between water adsorption on brown coal and the initial stage of coal oxidation.
We present herein a novel ratiometric fluorescent probe (1) for benzoyl peroxide (BPO). Probe 1 was obtained by coupling the recognition unit of arylboronate to a benzothiazole-derived fluorophore. ...The probe solution is colorless and displays weak blue fluorescence at 460 nm. Upon the addition of BPO, the arylboronate substituent can be removed via oxidation and 1,4-elimination processes. The released fluorophore emits strong yellow-greenish fluorescence at 546 nm. The ratiometric response of the probe is highly selective and sensitive for BPO. The dynamic range was fitted over 1.0 – 75.0 μM with a detection limit of 0.26 μM. In addition, the probe was applied to quantitative detection of BPO in real samples of wheat flour and an antimicrobial agent. Cellular experiments further demonstrated that probe 1 can be effectively utilized for imaging BPO in living cells.
The read sensor bias point plays an important role in the presence of media field as the aspect ratio of the sensor is scaled down. The change in the bias point also affects the asymmetry of the read ...sensor. The bias point shift is studied experimentally in a spin stand by measuring the change in tunneling magnetoresistive (TMR) resistance in the presence of the media field. The change in the TMR resistance depends on the direction of the media field and the rotation of the free-layer magnetization with respect to the media field. The bias point shift and the associated change in asymmetry in the presence of the media field are calculated from the TMR resistance, and a test based on the bias point shift is proposed to screen the unstable read sensors.
This work provides mesoscale models for the anomalous diffusion of a polymer chain on a heterogeneous surface with rearranging randomly distributed adsorption sites. Both the "bead-spring" model and ...oxDNA model were simulated on supported lipid bilayer membranes with various molar fractions of charged lipids, using Brownian dynamics method. Our simulation results demonstrate that "bead-spring" chains exhibit sub-diffusion on charged lipid bilayers which agrees with previous experimental observations for short-time dynamics of DNA segments on membranes. In addition, the non-Gaussian diffusive behaviors of DNA segments have not been observed in our simulations. However, a simulated 17 base pairs double stranded DNA, using oxDNA model, performs normal diffusion on supported cationic lipid bilayers. Due to the number of positively charged lipids attracted by short DNA is small, the energy landscape that the short DNA experiences during diffusion is not as heterogeneous as that experienced by long DNA chains, which results in normal diffusion rather than sub-diffusion for short DNA.
Both molecular dynamics (MD) and nonequilibrium molecular dynamics (NEMD) simulations were performed to simulate coal ashes using the Guillot-Sator model in this work. The structural and transport ...properties of coal ashes at high temperatures have been obtained. Superheating of coal ash system with anorthite crystal structure initial configuration has been observed for MD simulation which explains the discrepancy between previous MD simulation results and FactSage thermochemical calculations. The fluxing effects of both calcium oxide and sodium oxide have been investigated systematically through MD and NEMD simulations. Moreover, the viscosities of coal ash systems have been computed by two methods: (1) Stokes-Einstein equation; (2) NEMD simulations. Estimations of viscosities for various coal ash systems based on Stokes-Einstein equation exhibit a strong temperature dependence of viscosity, which agrees with previous experimental results. On the other hand, NEMD simulation results that showed a strong shear-thinning feature, failed to reproduce this strong temperature dependence of viscosity, possibly due to the short simulation time. Nevertheless, NEMD simulations not only provide us detailed information about atoms dynamics under shear, but also allow us to model the coal ash system far from equilibrium which cannot be accessed by thermodynamics calculation using software like FactSage.
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•Composite zeolite films were successfully synthesised and applied.•Composite zeolite films had excellent anti-carbon deposition.•Reaction mechanism for MTA with increasing in acidity ...was proposed.
In order to further improve the catalytic performance of zeolite catalyst for methanol to aromatics (MTA) technology, the double-tier SAPO-34/ZSM-5/quartz composite zeolite films were successfully synthesized via hydrothermal crystallization. The Si/Al ratio of SAPO-34 film was used as the only variable to study this material. The composite zeolite material with 0.6Si/Al ratio of SAPO-34 has the largest mesoporous specific surface area and the most suitable acid distribution. The catalytic performance for the MTA process showed that 0.6-SAPO-34/ZSM-5/quartz film has as high as 50.3% benzene-toluene-xylene selectivity and 670 min lifetime. The MTA reaction is carried out through the path we designed to effectively avoid the hydrocarbon pool circulation of ZSM-5 zeolite, so as to improve the aromatics selectivity and inhibit the occurrence of deep side reactions to a great extent. The coke deposition behavior was monitored by thermogravimetric analysis and gas chromatograph/mass spectrometer, it is found that with the increase of Si/Al ratio, the active intermediates changed from low-substituted methylbenzene to high-substituted methylbenzene, which led to the rapid deactivation of the catalyst. This work provides a possibility to employ the synergy effect of composite zeolite film synthesizing anti-carbon deposition catalyst in MTA reaction.
Near infrared light-emitting diode (LED) based on p-NiO/n-InN/n-GaN was realized by plasma-assisted molecular beam epitaxy (PAMBE) combined with radio frequency (rf) magnetron sputtering. The device ...exhibited diode-like rectifying current–voltage characteristics with a turn-on voltage of 1.0V. Under forward bias, prominent near infrared (NIR) emissions were observed at peak around 1570nm at room temperature. The NIR emission was ascribed to the band-edge emission of InN epilayer based on the photoluminescence spectrum and band diagram of the heterojunction. Moreover, the study of the LED in terms of the stability was also discussed.
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