Facile synthesis of graphene via reduction of graphene oxide by artemisinin in ethanol

The preparation of reduced graphene oxide(RGO)by chemical reduction of graphene oxide(GO)usually involves highly toxic reducing agents which are harmful to the environment and human health.In this paper,a mediated facile and relative green approach for the preparation of RGO in ethanol using artemisinin as a reducing agent is reported for the first time.The morphology and de-oxidation efficiency of the obtained RGO were characterized by transmission electron microscope(TEM),atomic force microscope(AFM),and X-ray photoelectron spectroscopy(XPS).The results showed that artemisinin can effectively reduce GO into few-layered RGO with a high carbon to oxygen ratio(11.7).The mechanism for elimination of oxygen-containing functional groups decorated on GO nanosheets by artemisinin was proposed.The important features of relatively environmentally friendly and facile operation procedures endow this approach with great promise in the mass production of RGO and various graphene-based materials,especially for biomaterials.

Influence of order degree of coaly graphite on its structure change during preparation of graphene oxide

Coaly graphite is an important natural graphite resource that derived from coal under a natural process that associated with igneous intrusion.Flake graphite is usually used for the chemical synthesis of graphene oxide(GO),the main precursor for preparation of graphene,but few papers pay attention to preparing GO using coaly graphite.In this paper,four kinds of natural coaly graphite with different graphitization degrees were exposed to a modified Hummer’s oxidation method to prepare GO.The flake graphite sample was also used for comparison.The results showed that the structural change process from graphite to GO were significantly affected by the graphitization degree of the original coaly graphite.The relationship between yields of GO and graphitization degrees of the coaly graphite was explored.The mechanism of why the graphite with low graphitization degrees cannot be totally oxidized was proposed.Coaly graphite with a graphitization degree of higher than 80% was easier to be oxidized and yielded the same amount of GO as the flake graphite did,suggesting it is the potential substitute for the flake graphite to produce GO in bulk quantities.

Diurnal Circadian Lighting Accumulation Model:A Predictor of the Human Circadian Phase Shift Phenotype

Light is an important external factor that affects human circadian rhythms.This study aimed to explore the effects of different dimensions of diurnal light exposure on the physiological circadian phase shift(CPS)of the human body.A strict light exposure experiment with different timing schemes(8:00-12:00,13:00-17:00,18:00-22:00),durations(4 h,8 h)and effective circadian stimulus levels(circadian stimulus:0.35,0.55)was performed in an enclosed laboratory.Fourteen participants,including seven males and seven females,with a mean age of 24.29±2.43(mean±standard deviation),participated in this experiment and experienced all six lighting schemes.The results showed that both time factor(F_(3,40)=29.079,p<0.001,the power of the sample size=0.98)and circadian stimulus levels(T_(20)=−2.415,p=0.025,the power of sample size=0.76)sig-nificantly affect the CPS.On this basis,a diurnal circadian lighting accumulation(DCLA)-CPS model was proposed in the form of the Boltzmann function,and was validated by experimental data with high correlation(R^(2)=0.9320,RSS=0.1184),which provides strong support for rationally arranging the light level at different times of the day.