Treatment of Textile Dye Effluent Using a Self-made Positively Charged Nanofiltration Membrane

A selfmade positively charged nanofiltration （NF） membrane was used to treat textile dye effluent to generate water for reuse, and the factors affecting nanofiltration process such as operating pressure, feed flow and membrane cleaning were investigated. With an applied pressure of 1.0 MPa and a feed flow of 40 L/h, this NF membrane has a removal of 93.3% for CODor and a reduction of approximately 51.0% in TDS, salinity and conductivity achieving the chroma removal of 100%. The permeate obtained through this membrane is suitable for recycling. Moreover, the membrane could be reused after being cleaned with 1% NaOH solution.

Electron G-Factor Anomaly and the Charge Thickness

The electron g-factor relates the magnetic moment to the spin angular momentum. It was originally theoretically calculated to have a value of exactly 2. Experiments yielded a value of 2 plus a very small fraction, referred to as the g-factor anomaly. This anomaly has been calculated theoretically as a power series of the fine structure constant. This document shows that the anomaly is the result of the electron charge thickness. If the thickness were to be zero, g = 2 exactly, and there would be no anomaly. As the thickness increases, the anomaly increases. An equation relating the g-factor and the surface charge thickness is presented. The thickness is calculated to be 0.23% of the electron radius. The cause of the anomaly is very clear, but why is the charge thickness greater than zero? Using the model of the interior structure of the electron previously proposed by the author, it is shown that the non-zero thickness, and thus the g-factor anomaly, are due to the proposed positive charge at the electron center and compressibility of the electron material. The author’s previous publication proposes a theory for splitting the electron into three equal charges when subjected to a strong external magnetic field. That theory is revised in this document, and the result is an error reduced to 0.4% in the polar angle where the splits occur and a reduced magnetic field required to cause the splits.

Positively charged microporous ceramic membrane for the removal of Titan Yellow through electrostatic adsorption

To develop a depth filter based on the electrostatic adsorption principle, positively charged microporous ceramic membrane was prepared from a diatomaceous earth ceramic membrane.The internal surface of the highly porous ceramic membrane was coated with uniformly distributed electropositive nano-Y2O3 coating. The dye removal performance was evaluated through pressurized filtration tests using Titan Yellow aqueous solution. It showed that positively charged microporous ceramic membrane exhibited a flow rate of 421 L/（m^2·hr） under the trans-membrane pressure of 0.03 bar. Moreover it could effectively remove Titan Yellow with feed concentration of 10 mg/L between pH 3 to 8. The removal rate increased with the enhancement of the surface charge properties with a maximum rejection of 99.6%. This study provides a new and feasible method of removing organic dyes in wastewater. It is convinced that there will be a broad market for the application of charged ceramic membrane in the field of dye removal or recovery from industry wastewater.

Direct electrochemistry and enzymatic activity of hemoglobin in positively charged colloid Au nanoparticles and hemoglobin layer-by-layer self-assembly films

Alternate adsorption of positively charged colloid-Au nanoparticles(nano-Au^(⊕))and negatively charged hemoglobin(Hb)on L-cysteine(L-cys)modified gold electrode resulted in the assembly of{Hb/nano-Au^(⊕)}n layer-by-layer films/L-cys modified gold electrode.The nano-Au^(⊕)was characterized by transmission electron micrograph(TEM)and microelectrophoresis.The modified electrode interface morphology was characterized by electrochemical impedance spectroscopy(EIS),atomic force mi-croscopy(AFM),cyclic voltammograms(CV)and chronoamperometry.Direct electron transfer between hemoglobin and gold electrodes was studied,and the apparent Michaelis-Menten constant(k_(m)^(app))of the modified electrode was evaluated to be 0.10 mmol·L^(-1).Moreover,the higher activity of proteins in the nano-Au^(⊕)films could be retained compared with the electropolymerization membrane,since the pro-teins in nano-Au^(⊕)films retained their near-native structure.Direct electron transfer between hemoglo-bin and electrode and electrochemically catalyzed reduction of hydrogen peroxide on a modified elec-trode was studied,and the linear range was from 2.1×10^(-8)to 1.2×10^(-3)mol·L^(-1)(r=0.994)with a detection limit of 1.1×10^(-8)mol·L^(-1)H_(2)O_(2).

Unmodified and positively charged gold nanoparticles for sensitive colorimetric detection of folate receptor via terminal protection of small molecule-linked ss DNA

The detection of protein/small molecule interactions plays important roles in drug discovery and protein/metabolite interactions in biology. In this work, by coupling the terminal protection of small molecule-linked ss DNA strategy with the unmodified and positively charged gold nanoparticle((+)Au NP) nanoprobes, we have developed a sensitive and simple colorimetric sensor for the detection of folate receptor, a highly expressed protein in many kinds of malignant tumors. The target folate receptor binds the folate moieties of the folate-linked ss DNA through high affinity interactions and protects the protein-bound ss DNA from digestion by exonuclease I. The protected ss DNA thus adsorbs the((+)Au NP) through electrostatic interactions, leading to a red-to-blue color change of the sensing solution for sensitive colorimetric detection of folate receptor at the sub-nanomolar level. Besides, this colorimetric sensor shows high selectivity toward folate receptor against other control proteins. The developed sensor avoids the modification/conjugation of the Au NP nanoprobes and the involvement of any expensive instruments for signal transduction in protein detection. Featured with these obvious advantages, the colorimetric sensor strategy demonstrated herein can be easily expanded for sensitive and convenient detection of various protein/small molecule interactions.

Three positive charge nonapoptotic-induced photosensitizer with excellent water solubility for tumor therapy

Photodynamic therapy(PDT)has emerged as a significant cancer therapy option.Currently,cation-based organic small molecule aggregation-induced emission(AIE)photosensitizers(PSs)attract the wide atten-tion of many scientists,due to improved reactive oxygen species(ROS)production after cationization.However,such PSs tend to localize only the mitochondria,limiting the death way of tumor cells(usu-ally apoptosis)during PDT process,which may affect the therapeutic effect under some circumstances.Herein,we designed a novel water-soluble three positive charge PS,TPAN-18F,which could be distributed uniformly in cell cytoplasm and had distribution in different sub-organelles(mitochondria,endoplasmic reticulum,lysosome).The experimental results showed that TPAN-18F-based PDT process can not only disrupt mitochondrial functions(reducing ATP production and destroying mitochondrial membrane po-tential),but also elevate the intracellular lipid peroxides(LPOs)level,which evoke the non-apoptotic death manner of tumor cells.Further,in vivo studies showed that TPAN-18F-based PDT could effectively inhibit tumor growth.Accordingly,we believe that the construction of TPAN-18F is suggestive for tumor non-apoptotic therapy.

Study on the recovery of NBTI of ultra-deep sub-micro MOSFETs

Taking the actual operating condition of complementary metal oxide semiconductor （CMOS） circuit into account, conventional direct current （DC） stress study on negative bias temperature instability （NBTI） neglects the detrapping of oxide positive charges and the recovery of interface states under the ＇low＇ state of p-channel metal oxide semiconductor field effect transistors （MOSFETs） inverter operation. In this paper we have studied the degradation and recovery of NBTI under alternating stress, and presented a possible recovery mechanism. The three stages of recovery mechanism under positive bias are fast recovery, slow recovery and recovery saturation.

Actions of negative bias temperature instability （NBTI） and hot carriers in ultra-deep submicron p-channel metal-oxide-semiconductor field-effect transistors （PMOSFETs）

Hot carrier injection （HCI） at high temperatures and different values of gate bias Vg has been performed in order to study the actions of negative bias temperature instability （NBTI） and hot carriers. Hot-carrier-stress-induced damage at Vg = Vd, where Vd is the voltage of the transistor drain, increases as temperature rises, contrary to conventional hot carrier behaviour, which is identified as being related to the NBTI. A comparison between the actions of NBTI and hot carriers at low and high gate voltages shows that the damage behaviours are quite different： the low gate voltage stress results in an increase in transconductance, while the NBTI-dominated high gate voltage and high temperature stress causes a decrease in transconductance. It is concluded that this can be a major source of hot carrier damage at elevated temperatures and high gate voltage stressing of p-channel metal-oxide-semiconductor field-effect transistors （PMOSFETs）. We demonstrate a novel mode of NBTI-enhanced hot carrier degradation in PMOSFETs. A novel method to decouple the actions of NBTI from that of hot carriers is also presented.

Arc Stability Characterization of Double Coated Electrodes for Hardfacing

The aim of this work is to establish the influence of the relative position of the alloy charge C-Cr-Mn in the structure of the coating of rutile electrodes for hardfacing,on the operational behavior(arc stability).For this,three variants of electrodes with similar chemical composition are elaborated in the metallic core and the coating,differentiating only in the relative position that occupies the alloy charge(C-Cr-Mn)in the structure of the coating:internal,external and homogeneous.For the development of the research,a completely random design is used.The operative characterization of the electrodes is performed in terms of the arc stability.In conclusion,it can be seen that the position of the alloy load influences the operation behavior(stability of the arc).The variant of internal alloy charge in the coating presents the better arc stability performance.

Potential distribution around a test charge in a positive dust-electron plasma

The electrostatic potential caused by a test-charge particle in a positive dust-electron plasma is studied, accounting for the d^Lst-charge fluctuations associated with ultraviolet photoelectron and thermionic emissions. For this purpose, the set of Vlasov-Poisson equations coupled with the dust charging equation is solved by using the space-time Fourier transform technique. As a consequence, a modified dielectric response function is obtained for dust-acoustic waves in a positive dust-electron plasma. By imposing certain conditions on the velocity of the test charge, the electrostatic potential is decomposed into the Deby^Hiickel （DH）, wake-field （WF）, and far-field （FF） potentials that are significantly modified in the limit of a large dust-charge relaxation rate both analytically and numerically. The results can be helpful for understanding dust crystallization/coagulation in two- component plasmas, where positively charged dust grains are present.

solitary waves shock waves dust charge variation dusty plasma

The nonlinear propagation of dust acoustic waves is investigated in four-component plasmas consisting of positively charged dust grains, trapped ions, nonthermal electrons, and photoelectron due to ultraviolet irradiation.We use generalized viscoelastic hydrodynamic model for strongly coupled dust grain. In the weak nonlinearity limit, a modified Kadomstev–Petviashvili（KP） equation and a modified KP-Burger equation, which have a damping term coming from nonadiabatic charge variation, have been derived in the kinetic regime and hydrodynamic regime, respectively. With the increasing of UV photon flux, the hydrodynamic regime changes to kinetic regime. The approximate analytical line soliton and shock solutions are investigated in the kinetic regime and hydrodynamic regime, respectively.

Numerical simulation of the effect of lower positive charge region in thunderstorms on different types of lightning

Combined with the existing stochastic lightning parameterization scheme, a classic tripole charge structure in thunderstorms is assumed in the paper, and then 2-dimensional fine-resolution lighting discharge simulations are performed to quantitatively investigate the effect of lower positive charge(LPC) on different types of lightning. The results show:(1) The LPC plays a key role in generating negative cloud-to-ground(CG) flashes and inverted intra-cloud(IC) lightning, and with the increase of charge density or distribution range of LPC region, lightning type changes from positive polarity IC lightning to negative CG flashes and then to inverted IC lightning.(2) Relative to distribution range of charge regions, the magnitude of charge density of the LPC region plays a dominant role in lightning type. Only when the maximal charge density value of LPC region is within a certain range, can negative CG flashes occur, and the occurrence probability is relatively fixed.(3) In this range, the charge density and distribution range of LPC region jointly determine the occurrence of negative CG flashes, which has a linear boundary with the trigger condition of IC lightning.(4) The common effect of charge density and distribution range of the LPC region is to change the distribution of positive potential well of bottom part of thunderstorms, and inverted IC lightning occurs when the initial reference potential is close to 0 MV, and negative CG flashes occur when the initial reference potential is far less than 0 MV.

Positive Charge Region in Lower Part of Thunderstorm and Preliminary Breakdown Process of Negative Cloud-to-Ground Lightning

A new lightning locating technology, called Lightning Mapping Array （LMA）, has been developed. The system takes advantage of GPS technology to measure the times of arrival （TOA） of lightning impulsive very high frequency （VHF） radiation events at each remote location. The spatiotemporal development processes of lightning are described in three-dimension by measurement of the system with high time resolution （50 ns） and space precision （50-100 m）. The charge structures in thunderstorm and their relationship with lightning discharge processes are revealed. The temporal and spatial characteristics of preliminary breakdown process involved in negative cloud-to-ground （CG） lightning discharges are analyzed based on the data of lightning VHF radiation events. The effect of positive charge region in lower part of thunderstorm on the occurrence of negative CG lightning discharge is discussed. The results indicate that the preliminary breakdown process with longer duration in negative CG lightning discharges is an intracloud discharge process. It occurs between negative and positive charge regions located in middle and lower parts of thunderstorm respectively. It initiates from the negative charge region and propagates downward. After propagating into the positive charge region, the lightning channel develops horizontally. The characteristics of the preliminary breakdown process are consistent with that of intracloud lightning discharges. The stepped leaders are initiated by the K type breakdown which occurs in the last stage of the preliminary breakdown process and develops downward through the positive charge region. The existence of positive charge region in lower part of thunderstorm results in the occurrence of preliminary breakdown process with longer duration before the return stroke of negative CG lightning discharges.

Kinetically regulated one-pot synthesis of cationic gold nanoparticles and their size-dependent antibacterial mechanism

Cationic gold nanoparticles(cAuNPs)have been regarded as promising candidates for antibacterial applications due to their high surface charge density,favorable biocompatibility,and controllable surface chemistry.Nevertheless,the complicated fabrication process and unclear antibacterial mechanism have greatly hindered the further biomedical application of cAuNPs.Herein,we have developed a simple and controllable strategy for synthesizing cAuNPs with tailored size and antibacterial behavior by kinetically modulating the reaction process.Specifically,a functional ligand,(11-mercaptoundecyl)-N,N,Ntrimethylammonium bromide(MUTAB),was chosen to chemically manipulate the positive surface charge of cAuNPs via a one-step strategy.The size of cAuNPs could be flexibly adjusted from 1.1 to 14.8 nm by simply elevating the stirring speed of the reaction from 0 to 1500 rpm.Further studies revealed that the antibacterial effect of cAuNPs was strongly correlated with the particle size.MUTAB-protected ultrasmall gold nanoclusters(MUTAB-AuNCs)were able to eradicate E.coli at a concentration as low as 1.25μg mL^(-1),while the minimum inhibitory concentration of MUTAB-AuNPs with a large size for E.coli was 5μg mL^(-1).Mechanistic investigation revealed that MUTAB-AuNPs were able to damage the bacterial membrane and stimulate the production of reactive oxygen species more effectively than MUTAB-AuNCs.Conversely,MUTAB-AuNCs were more active in inducing membrane depolarization in contrast to MUTAB-AuNPs,suggesting the unique size-dependent antibacterial manner of cAuNPs.This study presents a new strategy for the controlled preparation of cAuNPs with distinct sizes and antibacterial behavior,laying a valuable foundation for developing efficient cationic NP-based bactericidal agents.

Novel polyethyleneimine/TMC-based nanofiltration membrane prepared on a polydopamine coated substrate

Most commercial NF membranes are negatively charged at the pH range of a typical feed solution. In order to enhance the removal of cations （such as Mg2＋ or Ca2＋）, we utilized polyethyleneimine （PEI） and trimesoyl chloride （TMC） to perform interfacial polymerization reaction on a polydopamine coated hydrolyzed polyacry-lonitrile substrate to obtain a positively charged nanofiltration membrane. Effects ofpolydopamine coating time, PEI concentration, TMC reaction time and concentration on the membrane physicochemical properties and separation performance were systematically investigated using scanning electron microscopy, streaming potential and water contact angle measurements. The optimal NF membrane showed high rejection for divalent ions （93.6±2.6% for MgSO4, 92.4±1.3% for MgCl2, and 90.4±2.1% for Na2SO4）, accompanied with NaCl rejection of 27.8±2.5% with a permeation flux of 17.2±2.8 L.m-2.h-1 at an applied pressure of 8 bar （salt concentrations were all 1000 mg.L-1）. The synthesized membranes showed promising potentials for the applications of water soft-ening.

Hot-carrier-induced on-resistance degradation of step gate oxide NLDMOS

The hot-carrier-induced on-resistance degradations of step gate oxide NLDMOS （SG-NLDMOS） transistors are investigated in detail by a DC voltage stress experiment, a TCAD simulation and a charge pumping test. For different stress conditions, degradation behaviors of SG-NLDMOS transistors are analyzed and degradation mechanisms are presented. Then the effect of various doses of n-type drain drift （NDD） region implant on Ron degradation is investigated. Experimental results show that a lower NDD dosage can reduce the hot-carrier induced Ron degradation effectively, which is different from uniform gate oxide NLDMOS （UG-NLDMOS） transistors.