Synthesis of carbon nitride in moist environments:A defect engineering strategy toward superior photocatalytic hydrogen evolution reaction

Intimate understanding of the synthesis-structure-activity relationships is an accessible pathway to overcome the intrinsic challenges of carbon nitride(g-C_(3)N_(4))photocatalysts.This work looks in the effects of humidity of the synthesis process to the morphology,chemical structure,band structure as well as the photocatalytic activity of g-C_(3)N_(4) materials.Four g-C_(3)N_(4) samples were prepared by heating melem in four gas environments:dry Ar,dry Air,moist Ar and moist Air.The photocatalytic activity measurements revealed that the samples synthesized in moist inert and oxidic gases environments displayed 20 and 10 times the photocata lytic H_(2) evolution activity of the samples synthesized in dry inert and oxidic gases environments,respectively.The reasons for this remarkable variety in photocata lytic activities had been through investigated.After all,the terminations of the carbon vacancies were identified as the dominant factor in enhancing H_(2) evolution performance.The work here thus demonstrating an example of defect engineering.

The Level of Serum Intact Terminal Peptide of Procollagen and Its Clinical Significance in Patients with Chronic Keshan Disease

Objectives To evaluate the changes of serum intact terminal peptide of procollagen in patients with chronic Keshan disease (KD) and investigate their clinical significance. Methods The concentrations of serum intact N-terminal peptide of type procollagen (P NP) and intact N-terminal peptide of type procollagen were measured by radioimmunoassay in 35 patients with chronic KD and 31 normal control. Doppler ultrasounds was used to determine several parameters of left ventricular systole and diastole functions. Results The concentration of serum P NP (74.07±16.74)μg/L and the ratio of P NP/ P NP (18.02 ±4.60) in chronic KD were significantly increased as compared to the control (39.63±12.07 μg/L, 12.12±4.24; P< 0.001). Serum P NP (4.19±0.64)μg/L in chronic KD was higher than that in the control (3.36±0.65 μg/L,P < 0.001) too. The higher of serum concentration of P NP and the ratio of P NP/ P NP, the worse of cardiac function in patients with chronic KD. A negative correlation was found between serum P NP/ P NP, P NP and VE/VA, LVEF (γ=-0.4502, -0.4608, P< 0.01 and γ=-0.3936, -0.3904, respectively; P<0.05). Conclusions These findings suggested that tissue synthesis of collagen type and type was abnormally increased in chronic KD. On the other hand, our results indicated that P NP and P NP were related to several functional alterations of the left ventricle. Serum procollagen peptide measurements might therefore provide indirectly diagnostic information on myocardial fibrosis associated with chronic KD.

Design,fabrication and characterization of dual-channel real space transfer transistor

In this paper,using aδ-doping dual-channel structure and GaAs substrate,a real space transfer transistor(RSTT)is designed and fabricated successfully.It has the standardΛ-shaped negative resistance I-V characteristics as well as a level and smooth valley region that the conventional RSTT has.The negative resistance parameters can be varied by changing gate voltage(VGS).For example,the PVCR varies from 2.1 to 10.6 while VGS changes from 0.6 V to 1.0 V.The transconductance for IP(ΔIP=ΔVGS)is 0.3 mS.The parameters of VP,VV and threshold gate voltage(VT)for negative resistance characteristics arising are all smaller than the value reported in the literature.Therefore,this device is suitable for low dissipation power application.