Search

MgPc photosensitizers facilitate electron excitation in the NIR region to further enhance the photocatalytic activity of Bi2WO6.

Photocatalysis is a perennial solution that promises to resolve deep-rooted challenges related to environmental pollution and energy deficit through harvesting the inexhaustible and renewable solar energy. To date, a cornucopia of photocatalytic materials has been investigated with the research wave presently steered by the development of novel, affordable, and effective metal-free semiconductors with fascinating physicochemical and semiconducting characteristics. Coincidentally, the recently emerged red phosphorus (RP) semiconductor finds itself fitting perfectly into this category ascribed to its earth abundant, low-cost, and metal-free nature. More notably, the renowned red allotrope of the phosphorus family is spectacularly bestowed with strengthened optical absorption features, propitious electronic band configuration, and ease of functionalization and modification as well as high stability. Comprehensively detailing RP's roles and implications in photocatalysis, this review article will first include information on different RP allotropes and their chemical structures, followed by the meticulous scrutiny of their physicochemical and semiconducting properties such as electronic band structure, optical absorption features, and charge carrier dynamics. Besides that, state-of-the-art synthesis strategies for developing various RP allotropes and RP-based photocatalytic systems will also be outlined. In addition, modification or functionalization of RP with other semiconductors for promoting effective photocatalytic applications will be discussed to assess its versatility and feasibility as a high-performing photocatalytic system. Lastly, the challenges facing RP photocatalysts and future research directions will be included to propel the feasible development of RP-based systems with considerably augmented photocatalytic efficiency. This review article aspires to facilitate the rational development of multifunctional RP-based photocatalytic systems by widening the cognizance of rational engineering as well as to fine-tune the electronic, optical, and charge carrier properties of RP.

Foxtail millet [Setaria italica (L.) P. Beauv.], as a rich source of folates, has been cultivated on arid infertile lands, for which N deficiency is one of the major issues. Growing environments might have a significant influence on cereal folate levels. However, little is known whether N deficiency modulates cereal folate levels. In order to obtain enriched folate foxtail millet production in nutrient-poor soil, we conducted a study investigating the content of folate derivatives of 29 diverse foxtail millet cultivars under two N regimes (0 and 150 kg N ha−1) for 2 years to explore folate potential grown under low N. The contents of total folate and most derivatives were reduced by N deficiency. The effect on total folate content caused by N was stronger than cultivar genotype did. Folate content of enriched folate cultivars was prone to be reduced by N deficiency. Structural equation models (SEMs) revealed that N fertilization had a positive indirect effect on grain folate content through influencing plant N and K accumulation. Collectively, the results indicate much more attention should be paid to N management when foxtail millet is cultivated in infertile soil, to improve foxtail millet folate contents.

Universal access to clean water has been a global ambition over the years. Photocatalytic water disinfection through advanced oxidation processes has been regarded as one of the promising methods for breaking down microbials. The forefront of this research focuses on the application of metal-free photocatalysts for disinfection to prevent secondary pollution. Graphitic carbon nitride (g-C3 N4 ) has achieved instant attention as a metal-free and visible-light-responsive photocatalyst for various energy and environmental applications. However, the photocatalytic efficiency of g-C3 N4 is still affected by its rapid charge recombination and sluggish electron-transfer kinetics. In this contribution, two-dimensionally protonated g-C3 N4 was employed as metal-free photocatalyst for water treatment and demonstrated 100 % of Escherichia coli within 4 h under irradiation with a 23 W light bulb. The introduction of protonation can modulate the surface charge of g-C3 N4 ; this enhances its conductivity and provides a "highway" for the delocalization of electrons. This work highlights the potential of conjugated polymers in antibacterial application.

Nitrogen defect-engineered g-C3N4 with high electron localization at the vacancy site manifested stronger interaction with CO2 molecules and concomitantly enhanced the reaction specificity towards CO, CH3OH and CH4 generations from CO2 reduction.

Photocatalytic reduction of CO

To assess real-world use of emicizumab in adult people with hemophilia A (PwHA) without inhibitors including healthcare resource utilization (HCRU) and costs. Adult, male PwHA without inhibitors initiating emicizumab (index date) were identified using IBM MarketScan after 10/4/2018. Patients were required to have continuous health insurance coverage for ≥180 days prior to and ≥90 days after index date and have ≥90 days of continuous use of emicizumab. Patients were followed until treatment gap, disenrollment, or end of data. Results were reported overall and among a subgroup with prior factor VIII (FVIII) prophylaxis. Emicizumab use, concomitant FVIII treatment use, HCRU, and costs were assessed separately over baseline, the emicizumab induction period, emicizumab maintenance period, and annualized. Among the 71 emicizumab patients (FVIII prophylaxis subgroup: 52) included in the study, the mean age was 35 (subgroup: 34) years and mean follow-up was 12 (subgroup: 11.1) months. At baseline, the annualized mean total healthcare cost was $532,948 (subgroup: $645,727). After emicizumab initiation, per-patient-per-month (PPPM) HCRU was higher in the emicizumab induction period compared to the maintenance period with higher monthly FVIII fills/in-office administrations (0.37 vs 0.17), non-FVIII outpatient visits (2.23 vs 1.55), and emergency department visits (0.06 vs 0.03). The FVIII prophylaxis subgroup yielded similar HCRU trends. Hemophilia treatment costs accounted for over 95% of total healthcare costs. The annualized mean cost was $50,491 (subgroup: $61,512) for concomitant FVIII treatment and $777,171 (subgroup: $793,168) for emicizumab and concomitant FVIII treatment for the first year of emicizumab treatment. This study represented experience with emicizumab after the approval for PwHA without inhibitors. The study cohort may not be representative of all PwHA taking emicizumab. The findings highlight the continued burden of treatment and healthcare cost for PwHA without inhibitors despite advances in treatment options.

CO2 photoreduction into hydrocarbon fuels is a promising strategy in closing the carbon cycle to realize a sustainable energy economy. Among the many photocatalysts that have been developed thus far, porous graphitic carbon nitride (gC6N6) has emerged as a potential photocatalyst candidate in view of its unique optoelectronic properties, metal-free nature and two-dimensional versatile structure that can be easily modified. In this work, the enhancement of equivalent stoichiometry carbon nitride (gC6N6) through single transition metal atom modification was systematically studied from first principles density functional theory calculations. The formation energy calculations revealed that incorporating single Co, Cu, Ni or Pd atom into gC6N6 is energetically favorable, with the exception of Pt. The computed density of states plot indicates that a greater degree of hybridization of the transition metal atom d-orbitals with the p-orbitals of O atom from CO2 will lead to stronger adsorption interaction. The optical absorption spectra show that Cu, Pd, and Pt promotes greater light absorption by extending the optical absorption to the NIR region. The presence of additional dopant states near the Fermi surface was found to have affected the optical absorption. The band structures of the Co,Cu,Pd,Pt@gC6N6 show bandgap narrowing due to the shifting of conduction band edge closer to the Fermi level. Contrastingly, Ni@gC6N6 exhibits bandgap narrowing through the shifting of the valence band edge to the Fermi level. The band edge positions suggest that anchoring gC6N6 with single Co, Cu, Ni, Pd and Pt atom dopants possesses the capability to reduce CO2 into C1 products. Among all the transition metals studied, Pd@gC6N6 and Cu@gC6N6 are identified as the most promising single-atom photocatalysts for CO2 reduction due to their energetically favorable formation energy, stable CO2 adsorption configuration, narrow bandgap, low charge carrier recombination, extended light absorption range and suitable band edge positions.

ZnIn

In this work, the intramolecular structure of a pristine graphitic carbon nitride (GCN) was modified to investigate how it would affect the photocatalytic activity towards hydrogen evolution reaction (HER) under simulated solar irradiation. The intramolecular bonding of GCN was broken by subjecting it to a simple thermal treatment under a controlled environment. Both experimental and computational studies revealed that removal of inter-heptazine CN(H)C groups from the pristine structure induced an amorphous phase and additional energy bands to GCN. It was also observed that a mid-gap state was formed between the conduction band (CB) of the amorphous carbon nitride (ACN) and the H+/H2 reduction potential. The presence of the mid-gap state not only served as an additional reduction site for HER, but also acted as a buffer to reduce the recombination rate of photogenerated charge carriers. The optimum ACN sample displayed an enhanced photocatalytic performance achieving a HER rate of 789 µmol/gcat, which was about 2-fold higher than that of pristine GCN. This could be ascribed to the synergistic effect of improved light absorption, increased surface area, suppressed charge recombination and increased charge carrier densities for the ACN samples to drive the overall reduction–oxidation process.

In recent years, graphitic carbon nitride (gC3N4) has hit the limelight as a bright, metal-free and visible-light responsive photocatalyst. Pristine gC3N4, however, suffers from inadequate light absorption profile, limited surface area and significant recombination of photo-induced electron-hole pairs, thus requiring reformative strategies. Herein, this work has employed elemental doping of oxygen to gC3N4 (O-gC3N4) and uncovered the evolution of properties that arises in conjunction with increasing doping level. These intrusive changes in properties by increasing oxygen doping levels are then evaluated based on the trends observed from photocatalytic hydrogen (H₂) evolution. It is revealed that oxygen doping had a competing dual effect to the photocatalytic activity. On one hand, oxygen doping introduced more porosity and added sub-gap impurity states in its electronic band structure, which resulted in enhanced light harvesting capabilities. On the other hand, impurity levels from high density oxygen groups behave detrimentally as potent electron-holes recombination centers. This became the governing factor for higher doping levels O-gC3N4, which thereby resulted in a weakened photoactivity compared to pristine gC3N4. In overall, it is hoped that the findings of this study can provide a new understanding of the rational design and oxygen-doping strategy for gC3N4 for its photocatalytic enhancement.

Variable message signs can display not only text information, but also graphic information. Graphic information can be identified further in the distance than text information. Besides, the graphical information is not limited by language, as different countries can use the same graphical signs. The paper studies driver's comprehension of various graphic of five signs via questionnaires. The results showed that driver's selection of graphical signs had significant differences; only graphic A and graphic B, and graphic B and graphic C of fog sign did not have significant differences. Based on hypothesis testing and multiple comparisons analyzed to obtain the graphics of the five signs, the conclusions provide a base reference for graphic design of highway variable message signs.

Mycophenolate mofetil (MMF) is a very powerful immunosuppressive drug used in preventing acute rejection in liver transplantation. However, MMF has some serious side effects, including hematologic and gastrointestinal disorders. This study was designed to investigate the relationship between the clinical events and the pharmacokinetics of mycophenolic acid (MPA) in Chinese liver transplant recipients. Sixty-three adult liver transplant recipients receiving 1.0 g of MMF twice daily in combination with tacrolimus were prospectively included. The MPA pharmacokinetic profiles (blood sampling time points: before the dose and 0.5, 1, 1.5, 2, 4, 6, 8, 10, and 12 hours after the dose) were monitored after transplantation. Every clinical event, including acute and MMF-related side effects, was monitored in all patients within 3 months. Two patients (3.2%) had an episode of acute rejection. Forty-two patients (66.7%) had 52 episodes of MMF-related side effects, including leukopenia, diarrhea, and infection. The 0-hour concentration (C(0h)), maximum (peak) concentration (C(max)), and area under the curve from 0 to 12 hours (AUC(0-12h)) in patients with side effects were significantly higher than those in patients without side effects (P < 0.05). The thresholds of side effects from receiver operating characteristic analysis were 2 mg/L (sensitivity, 52.4%; specificity, 90.5%) for C(0h), 10 mg/L (sensitivity, 45.2%; specificity, 85.7%) for C(max), and 40 mg h/L (sensitivity, 71.4%; specificity, 61.9%) for AUC(0-12h) (P < 0.05). Leukopenia was discriminated effectively in C(0h) and in C(max) (P < 0.05). These results demonstrate the close relationship between leukopenia and MPA pharmacokinetic parameters in the early period after liver transplantation. C(0h) and AUC(0-12h) of MPA could predict the subsequent occurrence of leukopenia. These values may be used in routine monitoring for MMF therapy.

A high energy resolution X-ray spectrometer based on Silicon Drift Detector is described in this paper. The spectrometer consists of the SDD detector module, the analog electronics for shaping and filtering and the digital electronics for peak detection and data transfer. The system can working at room temperature as a thermo electric cooler (Peltier Element) is integrated into the SDD chip. The dynamic range is about 1 keV to 10 keV. Test results indicated high energy resolution Full Width at Ha lf Maximum (FWHM), which is better than 160 eV @ 5.9 keV with the incoming photon of radioisotopes ( 55 Fe).

We report on the experimental results of a lateral semi-insulating GaAs photoconductive switch, with a gap of 8 mm between two electrodes, triggered by 1064 nm laser pulses at a wavelength beyond the GaAs absorption edge. Both the linear and nonlinear modes of the switch were observed when it was triggered by light pulses with an energy of 1.9 mJ and a pulse width of 60 ns, and operated at high voltages of 3 and 5 kV. The results show that when the semi-insulating GaAs photoconductive switch operates under an electrical field of 4.37 kV/cm, it will enter into the linear mode first, and then the switch will undergo the nonlinear mode (lock-on) after a delay of about 20-100 ns. It is worth noticing that the delay time under high light energy is longer than that in the low optical energy. The non-intrinsic absorption mechanism is discussed. EL2 deep level defects and double-photon absorption in GaAs may play a key part in the absorption process.

依据密度泛函理论和电负性均衡原理,由分子中原子有效电负性更为精密的表达式,提出和建立了计算基团电负性及基团中原子电荷分布的新方案,并给出了一些常见原子的电负性和硬度的各类价态参数。通过对100多个基团进行的计算、分析和比较,表明该方案的结果是合理的和可以推广应用的。

以密度泛函理论表述的电负性及其均衡原理为基础,以组成原子电负性的调和平均为分子电负性参考取值,提出和设计了直接计算分子中原子电荷分布的新方案,避免了原算法中的多元回归和参数的多重选择,给出了分子环境下原子电负性和硬度的价态标度.本方案能更简便广泛的应用于大分子中原子电荷分布的计算,结果与ab initio STO-3G的结果符合相当好.

Rational combination of aggregation-induced emission active luminogens and mesogens generates high solid-state efficiency luminescent liquid crystals, thus resolving the problem of aggregation-caused quenching normally occurs in the fabrication of luminescent mesomorphic films.

Considering that semi-insulating gallium arsenide photoconductive switches can be triggered into the high gain mode and no reliable theories can account for the observed transient characteristics, we propose the monopole charge domain model to explain the peculiar switching phenomena occurring in the high gain mode and we discuss the requirements for the lock-on switching. During operation on this mode, the applied field across the switch and the lock-on field are all larger than the Gunn threshold field. Our developed monopole charge domain is based on the transferred-electron effect, but the domain is only composed of large numbers of electrons piled up due to the negative differential mobility. Using the model and taking the physical mechanism of the avalanche impact ionization and recombination radiation into consideration, we interpret the typical phenomena of the lock-on effect, such as the time delay between the beginning of optical illumination and turning-on of the switch, and the conduction mechanism of the sustaining phase. Under different conditions of bias field intensity and incident light energy, the time delay of the switching is calculated. The results show that the physical mechanisms of impact ionization and recombination radiation occurring in the monopole charge domain are responsible for the lock-on switching.

It is a crucial problem in the studies of the fluid on numerical simulations of the interfaces movement in multi-component fluids. Fluid dynamic characteristics are studied during shock waves pass helium bubble in this paper. These methods are used including high resolution discontinuous finite method for Fluid dynamic equations, Level set method for capturing moving interfaces and ghost fluid method with Isobaric fix for disposing the interfaces, which obtains profiles of the helium bubble, density contours and the curves of density and pressure with center axial direction. It is in good agreement for the general bubble shape and position compared with those in other numerical schemes.

Comparing with typical closed loop PID control strategy, dynamic matrix control (DMC) strategy performs well in tracking system and could also be directly applied to plant model with time-delay, however its ability of anti-interference is much weaker than typical PID control strategy. In this paper, DMC-PID cascade control strategy is proposed combined with the advantages of these two algorithms and was simulated in a uniaxial DC servo system in order to shorten the time-delay and enhance the stability of the system. The simulated results show that this double control strategy does much better than typical PID algorithm especially in tracking property, accuracy, robustness.

Based on theories of optimization for the route of heavy cargo transportation on roads and operating characteristics of heavy cargo transportation, an objective function which incorporates risk cost is developed for heavy cargo transportation.. In order to analyze the optimal route more clearly and conveniently, connectivity and network parameters such as blocking and restraint were defined in the Transcad software. Based on road sections, results minimizing total cost, including risk cost, are presented. An example verifies the feasibility of the model.

A mesocrack is in scale much larger than a microcrack but still smaller than a macrocrack, which has already been known to significantly influence the macroscopic behavior of engineering materials in transferring the load. An accumulative damage model is proposed in this work to account for the continuous degradation of the elastic moduli due to mesocrack formation in the rock medium under an excessive amount of volumetric strain. A power law is proposed to relate the isotropic damage measure D to the volumetric strain and the damage parameters involved in the model are determined from the peak state in the uniaxial stress and strain curve. A macrocrack is introduced to illustrate the continuous accrual of damage in the strain history due to geometrical singularity. The special elements are implemented in the near-tip region in the finite element analysis and the elastic moduli involved in the analytical expressions are updated according to the mesocrack damage developed in the strain history. As a natural consequence of mesocrack damage, the crack tip stress relief, the damage evolution in the neighborhood of the macrocrack tip and the nonhomogeneous response of material damage by softening are discussed in detail.

In this brief review, we look back on the conception of nano-atoms and their gradual evolutions into a new class of giant molecules in the context of soft matter science. The structural features and the characteristics about giant molecular self-assembly are summarized. It is found that these giant molecules with high conformational rigidities and precisely-defined shapes and symmetries can exhibit unusual phase structures and phase transition behaviors which are not commonly observed in conventional polymers. Their self-assembly is robust due to collective and cooperative interactions among nano-atoms, forming hierarchical structures that are sensitive to their primary structures. This modular feature is reminiscent to the domain concept in protein science. It is thus proposed that nano-atoms can serve as unique elements for macromolecular science.

In this paper, experiments of an all-solid-state insulated semi-insulating GaAs ultrafast surface photoconductive semiconductor switch triggered by nanosecond and femtosecond laser are reported. Both linear and nonlinear modes of the 3 mm-gap GaAs PCSS were observed when triggered by the /spl mu/J nanosecond laser. The current could be as high as 560 A. The same device also revealed good temporal characteristics when triggered with a 76 MHz femtosecond laser. The rise time of the PCSS response is less than 200 ps, and is limited by the coaxial cable.

Using the experimental methods about weak current and magnetic field, we make the experimental observation for oxide superconductor. The result obtained shows that there is Josephson weak link between superconducting grain. We consider that the weak link is the main reason of low Jc for oxide superconductor.

This paper reports a new method of measuring the work function of meterials. The method is based on accurate measuring of energy distribution of secondary electrons and contact potential difference of meterials. We call it the method of secondary electron emission-contact potential difference (SEE-CPD method). The work function of pure metals of Ni, Al, Au and Mo were measured by this method. The results are well consistent with that obtained by using photo-electron and Kelvin's method. The fundamentals and applications of the SEE-CPD method are proved to be correct and reliable.