The effects of various auditory takeover requests: A simulated driving study considering the modality of non-driving-related tasks.

With the era of automated driving approaching, designing an effective auditory takeover request (TOR) is critical to ensure automated driving safety. The present study investigated the effects of speech-based (speech and spearcon) and non-speech-based (earcon and auditory icon) TORs on takeover performance and subjective preferences. The potential impact of the non-driving-related task (NDRT) modality on auditory TORs was considered. Thirty-two participants were recruited in the present study and assigned to two groups, with one group performing the visual N-back task and another performing the auditory N-back task during automated driving. They were required to complete four simulated driving blocks corresponding to four auditory TOR types. The earcon TOR was found to be the most suitable for alerting drivers to return to the control loop because of its advantageous takeover time, lane change time, and minimum time to collision. Although participants preferred the speech TOR, it led to relatively poor takeover performance. In addition, the auditory NDRT was found to have a detrimental impact on auditory TORs. When drivers were engaged in the auditory NDRT, the takeover time and lane change time advantages of earcon TORs no longer existed. These findings highlight the importance of considering the influence of auditory NDRTs when designing an auditory takeover interface. The present study also has some practical implications for researchers and designers when designing an auditory takeover system in automated vehicles.

Single-Atom Anchored g-C3N4 Monolayer as Efficient Catalysts for Nitrogen Reduction Reaction.

Electrochemical N2 reduction reaction (NRR) is a promising approach for NH3 production under mild conditions. Herein, the catalytic performance of 3d transition metal (TM) atoms anchored on s-triazine-based g-C3N4 (TM@g-C3N4) in NRR is systematically investigated by density functional theory (DFT) calculations. Among these TM@g-C3N4 systems, the V@g-C3N4, Cr@g-C3N4, Mn@g-C3N4, Fe@g-C3N4, and Co@g-C3N4 monolayers have lower ΔG(*NNH) values, especially the V@g-C3N4 monolayer has the lowest limiting potential of -0.60 V and the corresponding limiting-potential steps are *N2+H++e-=*NNH for both alternating and distal mechanisms. For V@g-C3N4, the transferred charge and spin moment contributed by the anchored V atom activate N2 molecule. The metal conductivity of V@g-C3N4 provides an effective guarantee for charge transfer between adsorbates and V atom during N2 reduction reaction. After N2 adsorption, the p-d orbital hybridization of *N2 and V atoms can provide or receive electrons for the intermediate products, which makes the reduction process follow acceptance-donation mechanism. The results provide an important reference to design high efficiency single atom catalysts (SACs) for N2 reduction.

Theoretical exploration of the structural, electronic and optical properties of g-C3N4/C3N heterostructures.

Integration of graphene-like carbon nitride materials is essential for nanoelectronic applications. Using density-functional theory (DFT), we systematically investigate the structural, electronic and optical properties of a s-triazine-based g-C3N4/C3N heterostructure under different modified conditions. The g-C3N4/C3N van der Waals heterostructure (vdWH) formed has an indirect bandgap with type-II band alignment and the band structures can be tuned from type-II band alignment to type-I band alignment by applying biaxial strains and external electric fields (Efield). Compared to single transition metal (TM) atoms at g-C3N4/C3N surfaces, the TM atoms anchored in the interlayer region exhibit more stability, and the corresponding bandgaps are changed from 0.19 eV to 0.61 eV. In addition, the g-C3N4/C3N heterostructure has a strong absorption coefficient in the ultraviolet-visible light region along the x direction. It is found that compressive strain has a large influence on the absorption coefficient of the g-C3N4/C3N system. With the increased compressive strain, the absorption spectra in the visible light region disappeared. Tensile strain has a slight effect on the absorption range, but causes a red shift of the absorption spectrum. In comparison, the light absorption coefficient of the g-C3N4/C3N system remains almost unchanged under the Efield conditions. In summary, the formation of a s-triazine-based g-C3N4/C3N heterostructure has shown potential for applications in nanoelectronic and optoelectronic devices.

When to use vibrotactile displays? A meta-analysis for the role of vibrotactile displays in human-computer interaction.

OBJECTIVE: This study aims to investigate the benefits of unimodal tactile displays relative to other modal displays and the performance gains of adding redundant tactile displays by integrating empirical studies. BACKGROUND: Tactile displays have attracted increasing attention in recent years due to their unique advantages. Synthesizing experimental data is necessary to analyze the performance benefits of tactile displays for participants and better help practitioners in utilizing them. METHOD: Five meta-analyses were conducted. Two meta-analyses compared the participants' performance between tactile and other modal displays (visual vs. tactile and auditory vs. tactile). Three meta-analyses examined the performance gains of adding redundant tactile displays based on other modal displays (visual vs. visual + tactile, auditory vs. auditory + tactile, and visual + auditory vs. visual + auditory + tactile). The related moderator variables, the types of presented information and concurrent tasks, were analyzed. RESULTS: Little evidence shows the performance difference between tactile and auditory displays. Tactile displays are more beneficial than visual displays for presenting alert information or in the situation with a visual concurrent task. The performance gains of adding redundant tactile displays to other modal displays also depend on the specific type of presented information and the concurrent task. CONCLUSION: When using tactile displays to convey information, interface designers should consider the specific type of presented information and the concurrent tasks. APPLICATIONS: The present study's findings can provide some implications for designers to utilize tactile displays when they construct and implement information displays.

Optimal Time Intervals in Two-Stage Takeover Warning Systems With Insight Into the Drivers' Neuroticism Personality.

Conditional automated driving [level 3, Society of Automotive Engineers (SAE)] requires drivers to take over the vehicle when an automated system's failure occurs or is about to leave its operational design domain. Two-stage warning systems, which warn drivers in two steps, can be a promising method to guide drivers in preparing for the takeover. However, the proper time intervals of two-stage warning systems that allow drivers with different personalities to prepare for the takeover remain unclear. This study explored the optimal time intervals of two-stage warning systems with insights into the drivers' neuroticism personality. A total of 32 drivers were distributed into two groups according to their self-ratings in neuroticism (high vs. low). Each driver experienced takeover under the two-stage warning systems with four time intervals (i.e., 3, 5, 7, and 9 s). The takeover performance (i.e., hands-on-steering-wheel time, takeover time, and maximum resulting acceleration) and subjective opinions (i.e., appropriateness and usefulness) for time intervals and situation awareness (SA) were recorded. The results showed that drivers in the 5-s time interval had the best takeover preparation (fast hands-on steering wheel responses and sufficient SA). Furthermore, both the 5- and 7-s time intervals resulted in more rapid takeover reactions and were rated more appropriate and useful than the 3- and 9-s time intervals. In terms of personality, drivers with high neuroticism tended to take over immediately after receiving takeover messages, at the cost of SA deficiency. In contrast, drivers with low neuroticism responded safely by judging whether they gained enough SA. We concluded that the 5-s time interval was optimal for drivers in two-stage takeover warning systems. When considering personality, drivers with low neuroticism had no strict requirements for time intervals. However, the extended time intervals were favorable for drivers with high neuroticism in developing SA. The present findings have reference implications for designers and engineers to set the time intervals of two-stage warning systems according to the neuroticism personality of drivers.

Highly efficient catalytic properties of Sc and Fe single atoms stabilized on a honeycomb borophene/Al(111) heterostructure via a dual charge transfer effect.

Theoretical design and experimental fabrication of highly efficient single-atom catalysts (SACs) containing isolated metal atoms monodispersed on appropriate substrates have surged to the forefront of heterogeneous catalysis in recent years. Nevertheless, the instability of SACs, i.e., preferential clustering in chemical reaction processes, dramatically hinders their practical applications. In this paper, using first-principles calculations, we predict that a honeycomb borophene/Al(111) heterostructure can be an ideal candidate to stabilize and enhance the catalysis of many transition metal (TM) SACs via a dual charge transfer mechanism. The Al(111) substrate donates electrons to the pre-covered two-dimensional honeycomb borophene (h-B) to stabilize the latter, and the deposited TM atoms further provide electrons to the h-B, enhancing the covalent binding between the h-B and the Al(111) substrate. Intriguingly, during CO oxidation, the h-B/Al(111) heterostructure can in turn serve as an efficient electron reservoir to accept electrons from or donate electrons to the deposited TM-SACs and the reactants. Such a flexible dual charge transfer mechanism not only facilitates stabilizing the TM-SACs rather than clustering, but also effectively reduces the reaction barriers. Particularly, in contrast to expensive noble metal atoms such as Pd and Pt, low-cost Sc- and Fe-SACs are found to be the most promising SAC candidates that can be stabilized on h-B/Al(111) for O2 activation and CO oxidation, with fairly low reaction barriers (around 0.50-0.65 eV). The present findings may provide important theoretical guidance for the experimental fabrication of highly stable, efficient, and economic SACs stabilized on various heterostructure substrates.

Electrochemical Sensors and Biosensors for the Analysis of Tea Components: A Bibliometric Review.

Tea is a popular beverage all around the world. Tea composition, quality monitoring, and tea identification have all been the subject of extensive research due to concerns about the nutritional value and safety of tea intake. In the last 2 decades, research into tea employing electrochemical biosensing technologies has received a lot of interest. Despite the fact that electrochemical biosensing is not yet the most widely utilized approach for tea analysis, it has emerged as a promising technology due to its high sensitivity, speed, and low cost. Through bibliometric analysis, we give a systematic survey of the literature on electrochemical analysis of tea from 1994 to 2021 in this study. Electrochemical analysis in the study of tea can be split into three distinct stages, according to the bibliometric analysis. After chromatographic separation of materials, electrochemical techniques were initially used only as a detection tool. Many key components of tea, including as tea polyphenols, gallic acid, caffeic acid, and others, have electrochemical activity, and their electrochemical behavior is being investigated. High-performance electrochemical sensors have steadily become a hot research issue as materials science, particularly nanomaterials, and has progressed. This review not only highlights these processes, but also analyzes and contrasts the relevant literature. This evaluation also provides future views in this area based on the bibliometric findings.

Promote or inhibit: An inverted U-shaped effect of workload on driver takeover performance.

OBJECTIVE: In conditional automated driving (SAE Level 3), drivers are required to take over their vehicles when the automated systems fail. Non-driving related tasks (NDRTs) can positively or negatively affect takeover safety, but the underlying reasons for this inconsistency remain unclear. This study aims to investigate how various workload levels generated by NDRTs may influence the takeover performance of drivers and the lead time they require. METHOD: Fifty drivers were randomly distributed into five groups, which corresponded to five workload levels (1-4 levels generated by Tetris game; control level generated by monitoring). Each driver completed vehicle takeover tasks upon receiving takeover requests with various lead times (3, 5, 7, 9, and 11 s) while engaging in NDRTs. The drivers' takeover performance and subjective opinions were recorded. RESULTS: Drivers in the moderate workload condition (i.e., level 3) had significantly shorter takeover times and better takeover quality than those in the lower (i.e., level 1 and level 2) or higher (i.e., level 4) workload conditions. They also subjectively required less lead time in the moderate condition. Moreover, the drivers rated 7 s as the most appropriate lead time despite the improvement in their overall takeover performances with increased lead time. CONCLUSIONS: This study found an inverted U-shaped relationship between the drivers' workload generated by NDRTs and takeover performance. The moderate workload level (rather than the lower or higher workload level) led to a faster and better takeover performance, and it seemed to require minimal lead time for drivers. These findings help understand the relationship of drivers' workload during the automation and takeover performance in conditional automated driving. An important recommendation emerging from this work is to investigate what should be the most efficient method to detect the drivers' workload state real-time and give feedback to them when it comes to overload or underload during the automated driving.

Strain induced spin-splitting and half-metallicity in antiferromagnetic bilayer silicene under bending.

Searching for half-metals in low dimensional materials is not only of scientific importance, but also has important implications for the realization of spintronic devices on a small scale. In this work, we show theoretically that simple bending can induce spin-splitting in bilayer silicene. For bilayer silicene with Bernal stacking, the monolayer has a long range ferromagnetic spin order and between the two monolayers, the spin orders are opposite, giving rise to an antiferromagnetic configuration for the ground state of the bilayer silicene. Under bending, the antiferromagnetic spin order is retained but the energetic degeneracy of opposite spin states is lifted. Due to the unusual deformation potentials of the conduction band minimum (CBM) and valence band maximum (VBM) as revealed by density-functional theory calculations and density-functional tight-binding calculations, this spin-splitting is nearly proportional to the degree of bending deformation. Consequently, the spin-splitting can be significant and the desired half-metallic state may emerge when the bending increases, which has been verified by direct simulation of the bent bilayer silicene using the generalized Bloch theorem. Our results hint that bilayer silicene may be an excellent candidate for half-metallicity.

Unconventional deformation potential and half-metallicity in zigzag nanoribbons of 2D-Xenes.

Realization of half-metallicity (HM) in low dimensional materials is a fundamental challenge for nano spintronics and a critical component for developing alternative generations of information technology. Using first-principles calculations, we reveal an unconventional deformation potential for zigzag nanoribbons (NRs) of 2D-Xenes. Both the conduction band minimum (CBM) and valence band maximum (VBM) of the edge states have negative deformation potentials. This unique property, combined with the localization and spin-polarization of the edge states, enables us to induce spin-splitting and HM using an inhomogeneous strain pattern, such as simple in-plane bending. Indeed, our calculation using the generalized Bloch theorem reveals the predicted HM in bent zigzag silicene NRs. Furthermore, the magnetic stability of the long range magnetic order for the spin-polarized edge states is maintained well against the bending deformation. These aspects indicate that it is a promising approach to realize HM in low dimensions with the zigzag 2D-Xene NRs.

Influences of Experience and Visual Cues of Virtual Arm on Distance Perception.

Egocentric distance perception refers to the perception of distance from a target to a perceiver, which is an important component of visual space perception. It is important to activities in virtual environments and influenced by several factors, such as action capacities and visual cues. However, few studies have investigated such aspects. Hence, Experiments 1 and 2 investigated the effect of using experience and visual cues, respectively, of virtual arms on egocentric distance perception in near and far spaces at equal, prolonged, and shortened lengths of a virtual arm. Results revealed that using experience and visual cues of the virtual arm had a significant effect on egocentric distance perception when the length of virtual arm was equal to the real arm and prolonged but not when shortened. The egocentric distance perception on the conditions of having using experience and virtual arm was most precise. The findings provide implications for the design and implementation of virtual body self-representation in virtual environments.

Strain Engineering of a Defect-Free, Single-Layer MoS2 Substrate for Highly Efficient Single-Atom Catalysis of CO Oxidation.

Single-atom catalysts (SACs) are of great scientific and technical importance due to their low cost, high site density, and high specificity to enhance chemical reactions. Nevertheless, a major issue that severely limits the practical exploration of SACs is their instability, i.e., the preference of sintering and clustering over a defect-free substrate during operation. Here, we employ first-principles calculations to investigate how substrate engineering can stabilize SACs by strain-tuning the electronic interactions between the metal and the substrate using two Pd adatoms on a defect-free, single-layer MoS2 as a typical example. It is identified that the Pd2 dimer is prone to dissociate and form highly efficient SACs for CO oxidation due to the enhanced charge transfer and orbital hybridization with the MoS2 substrate under a suitable tensile strain. The straining induces a semiconductive-to-metallic phase transition of the substrate. Moreover, low-cost elements, such as Ag, Ni, Cu, and Cr, can also be stabilized into high-performance SACs for CO oxidation with tunable reaction barriers by straining. The present findings offer a new avenue to inhibit the transition metal atoms from clustering into nanoclusters/particles and provide a clear guidance for the development of highly cost-efficient and stable SACs on defect-free substrates.

Influences of Augmented Reality Assistance on Performance and Cognitive Loads in Different Stages of Assembly Task.

According to the assembly task model proposed by Stork and Schubö (2010), the assembly task is divided into commissioning and joining subtasks. Each subtask includes two sequential stages, namely, perception and response selection, and action. This division enables a convenient discussion of the influences of Augmented reality (AR) assistance on operators during different stages of an assembly task. Research results can provide a basis for the further analysis of the influence mechanism of AR assistance on an assembly task. This study is composed of three experiments. Experiment 1 explores the influences of AR assistance on the performance of the overall assembly task and the commissioning and joining subtasks. Combining a variation of task complexities, Experiments 2 and 3 discuss the influences of AR assistance on the different stages of the commissioning and joining subtasks. We found that AR assistance can shorten the time of the overall assembly task and subtasks (commissioning and joining) and reduce mistakes during these tasks. Moreover, AR assistance can decrease cognitive load in the commissioning subtask, but it increases cognitive load in the joining task with low complexity. In the perception and response selection stage of the commissioning and joining subtasks, AR assistance can shorten the time for users to recognize the target part and understand the assembly relation. This advantage is extremely significant for the high-complexity task. In the action stage of two subtasks, AR assistance can shorten the time for users to capture parts, but it prolongs the time for users to build parts.

The transcription factor OsSUF4 interacts with SDG725 in promoting H3K36me3 establishment.

The different genome-wide distributions of tri-methylation at H3K36 (H3K36me3) in various species suggest diverse mechanisms for H3K36me3 establishment during evolution. Here, we show that the transcription factor OsSUF4 recognizes a specific 7-bp DNA element, broadly distributes throughout the rice genome, and recruits the H3K36 methyltransferase SDG725 to target a set of genes including the key florigen genes RFT1 and Hd3a to promote flowering in rice. Biochemical and structural analyses indicate that several positive residues within the zinc finger domain are vital for OsSUF4 function in planta. Our results reveal a regulatory mechanism contributing to H3K36me3 distribution in plants.

Position-specific intron retention is mediated by the histone methyltransferase SDG725.

BACKGROUND: Intron retention (IR), the most prevalent alternative splicing form in plants, plays a critical role in gene expression during plant development and stress response. However, the molecular mechanisms underlying IR regulation remain largely unknown. RESULTS: Knockdown of SDG725, a histone H3 lysine 36 (H3K36)-specific methyltransferase in rice, leads to alterations of IR in more than 4700 genes. Surprisingly, IR events are globally increased at the 5' region but decreased at the 3' region of the gene body in the SDG725-knockdown mutant. Chromatin immunoprecipitation sequencing analyses reveal that SDG725 depletion results in a genome-wide increase of the H3K36 mono-methylation (H3K36me1) but, unexpectedly, promoter-proximal shifts of H3K36 di- and tri-methylation (H3K36me2 and H3K36me3). Consistent with the results in animals, the levels of H3K36me1/me2/me3 in rice positively correlate with gene expression levels, whereas shifts of H3K36me2/me3 coincide with position-specific alterations of IR. We find that either H3K36me2 or H3K36me3 alone contributes to the positional change of IR caused by SDG725 knockdown, although IR shift is more significant when both H3K36me2 and H3K36me3 modifications are simultaneously shifted. CONCLUSIONS: Our results revealed that SDG725 modulates IR in a position-specific manner, indicating that H3K36 methylation plays a role in RNA splicing, probably by marking the retained introns in plants.

Engineering Pichia pastoris for Efficient Production of a Novel Bifunctional Strongylocentrotus purpuratus Invertebrate-Type Lysozyme.

Lysozymes are known as ubiquitously distributed immune effectors with hydrolytic activity against peptidoglycan, the major bacterial cell wall polymer, to trigger cell lysis. In the present study, the full-length cDNA sequence of a novel sea urchin Strongylocentrotus purpuratus invertebrate-type lysozyme (sp-iLys) was synthesized according to the codon usage bias of Pichia pastoris and was cloned into a constitutive expression plasmid pPIC9K. The resulting plasmid, pPIC9K-sp-iLys, was integrated into the genome of P. pastoris strain GS115. The bioactive recombinant sp-iLys was successfully secreted into the culture broth by positive transformants. The highest lytic activity of 960 U/mL of culture supernatant was reached in fed-batch fermentation. Using chitin affinity chromatography and gel-filtration chromatography, recombinant sp-iLys was produced with a yield of 94.5 mg/L and purity of > 99%. Recombinant sp-iLys reached its peak lytic activity of 8560 U/mg at pH 6.0 and 30 °C and showed antimicrobial activities against Gram-negative bacteria (Vibrio vulnificus, Vibrio parahemolyticus, and Aeromonas hydrophila) and Gram-positive bacteria (Staphylococcus aureus and Bacillus subtilis). In addition, recombinant sp-iLys displayed isopeptidase activity which reached the peak at pH 7.5 and 37 °C with the presence of 0.05 M Na+. In conclusion, this report describes the heterologous expression of recombinant sp-iLys in P. pastoris on a preparative-scale, which possesses lytic activity and isopeptidase activity. This suggests that sp-iLys might play an important role in the innate immunity of S. purpuratus.

Application of AFP whole blood one-step rapid detection kit in screening for HCC in Qidong.

Hepatocellular carcinoma (HCC) is a big problem in China where the Hepatitis B (HBV) infection patients are near to 120 million. Early screening and diagnosis is the key to reduce the incidence and mortality of HCC. Serum AFP detection is the main methods for diagnosis, recurrent monitoring and therapeutic evaluation of primary HCC. Hepatitis patients should detect the AFP at least once every six months to help early diagnosis of HCC. Unfortunately, most hepatitis and other liver disease patients do not test their AFP regularly. Therefore, a rapid, convenient detect kit for AFP is necessary for the hepatitis patients to test AFP at home by themselves. It will be very helpful to the HCC early screening and early diagnosis. We screened 859 individuals who were HBsAg positive and had high risk of HCC in Qidong by using two different kits, AFP one-step rapid detection kit (Shanghai Outdo Biotech) and AFP Diagnostics ELISA kit (Zhengzhou Autobio Diagnostics), and compared the results. As a result, the positive accordance rate and the negative accordance rate of AFP one-step rapid detection kit and the Autobio ELISA kit were 95.65% (22/23) and 99.40% (831/836), respectively. The total diagnose accordance rate reached up to 99.30% (853/859). The screening results showed a high accordance rate of two methods. It is so meaningful to achieve home-test and improve HCC early screening and diagnosis by using AFP one-step rapid detection kit.

Interplay between the spin-selection rule and frontier orbital theory in O2 activation and CO oxidation by single-atom-sized catalysts on TiO2(110).

Exploration of the catalytic activity of low-dimensional transition metal (TM) or noble metal catalysts is a vital subject of modern materials science because of their instrumental role in numerous industrial applications. Recent experimental advances have demonstrated the utilization of single atoms on different substrates as effective catalysts, which exhibit amazing catalytic properties such as more efficient catalytic performance and higher selectivity in chemical reactions as compared to their nanostructured counterparts; however, the underlying microscopic mechanisms operative in these single atom catalysts still remain elusive. Based on first-principles calculations, herein, we present a comparative study of the key kinetic rate processes involved in CO oxidation using a monomer or dimer of two representative TMs (Pd and Ni) on defective TiO2(110) substrates (TMn@TiO2(110), n = 1, 2) to elucidate the underlying mechanism of single-atom catalysis. We reveal that the O2 activation rates of the single atom TM catalysts deposited on TiO2(110) are governed cooperatively by the classic spin-selection rule and the well-known frontier orbital theory (or generalized d-band picture) that emphasizes the energy gap between the frontier orbitals of the TM catalysts and O2 molecule. We further illuminate that the subsequent CO oxidation reactions proceed via the Langmuir-Hinshelwood mechanism with contrasting reaction barriers for the Pd monomer and dimer catalysts. These findings not only provide an explanation for existing observations of distinctly different catalytic activities of Pd@TiO2(110) and Pd2@TiO2(110) [Kaden et al., Science, 2009, 326, 826-829] but also shed new insights into future utilization and optimization of single-atom catalysis.

SET DOMAIN GROUP 708, a histone H3 lysine 36-specific methyltransferase, controls flowering time in rice (Oryza sativa).

As a key epigenetic modification, the methylation of histone H3 lysine 36 (H3K36) modulates chromatin structure and is involved in diverse biological processes. To better understand the language of H3K36 methylation in rice (Oryza sativa), we chose potential histone methylation enzymes for functional exploration. In particular, we characterized rice SET DOMAIN GROUP 708 (SDG708) as an H3K36-specific methyltransferase possessing the ability to deposit up to three methyl groups on H3K36. Compared with the wild-type, SDG708-knockdown rice mutants displayed a late-flowering phenotype under both long-day and short-day conditions because of the down-regulation of the key flowering regulatory genes Heading date 3a (Hd3a), RICE FLOWERING LOCUS T1 (RFT1), and Early heading date 1 (Ehd1). Chromatin immunoprecipitation experiments indicated that H3K36me1, H3K36me2, and H3K36me3 levels were reduced at these loci in SDG708-deficient plants. More importantly, SDG708 was able to directly target and effect H3K36 methylation on specific flowering genes. In fact, knockdown of SDG708 led to misexpression of a set of functional genes and a genome-wide decrease in H3K36me1/2/3 levels during the early growth stages of rice. SDG708 is a methyltransferase that catalyses genome-wide deposition of all three methyl groups on H3K36 and is involved in many biological processes in addition to flowering promotion.

Sub-surface alloying largely influences graphene nucleation and growth over transition metal substrates.

Sub-surface alloying (SSA) can be an effective approach to tuning surface functionalities. Focusing on Rh(111) as a typical substrate for graphene nucleation, we show strong modulation by SSA atoms of both the energetics and kinetics of graphene nucleation simulated by first-principles calculations. Counter-intuitively, when the sub-surface atoms are replaced by more active solute metal elements to the left of Rh in the periodic table, such as the early transition metals (TMs), Ru and Tc, the binding between a C atom and the substrate is weakened and two C atoms favor dimerization. Alternatively, when the alloying elements are the late TMs to the right of Rh, such as the relatively inert Pd and Ag, the repulsion between the two C atoms is enhanced. Such distinct results can be well addressed by the delicately modulated activities of the surface host atoms in the framework of the d-band theory. More specifically, we establish a very simple selection rule for optimizing the metal substrate for high quality graphene growth: the introduction of an early (late) solute TM in the SSA lowers (raises) the d-band center and the activity of the top-most host metal atoms, weakening (strengthening) the C-substrate binding, meanwhile both energetically and kinetically facilitating (hindering) the graphene nucleation, and simultaneously promoting (suppressing) the orientation disordering the graphene domains. Importantly, our preliminary theoretical results also show that such a simple rule is also proposed to be operative for graphene growth on the widely invoked Cu(111) catalytic substrate.