We investigate the structure, energetics, and the ideal tensile strength of tungsten （W） with hydrogen （H） using a first-principles method. Both density of states （DOS） and the electron localization function （ELF） reveal the underlying physical mechanism that the tetrahedral interstitial H is the most energetically favorable. The firstprinciples computational tensile test （FPCTT） shows that the ideal tensile strength is 29.1 GPa at the strain of 14% along the [001] direction for the intrinsic W, while it decreases to 27.1 GPa at the strain of 12% when one impurity H atom is embedded into the bulk W. These results provide a useful reference to understand W as a plasma facing material in the nuclear fusion Tokamak.
With the rapid development of information technology,the development of blockchain technology has also been deeply impacted.When performing block verification in the blockchain network,if all transactions are verified on the chain,this will cause the accumulation of data on the chain,resulting in data storage problems.At the same time,the security of data is also challenged,which will put enormous pressure on the block,resulting in extremely low communication efficiency of the block.The traditional blockchain system uses theMerkle Tree method to store data.While verifying the integrity and correctness of the data,the amount of proof is large,and it is impossible to verify the data in batches.A large amount of data proof will greatly impact the verification efficiency,which will cause end-to-end communication delays and seriously affect the blockchain system’s stability,efficiency,and security.In order to solve this problem,this paper proposes to replace the Merkle tree with polynomial commitments,which take advantage of the properties of polynomials to reduce the proof size and communication consumption.By realizing the ingenious use of aggregated proof and smart contracts,the verification efficiency of blocks is improved,and the pressure of node communication is reduced.
Jin WangWeiOuWenhai WangRSimon SherrattYongjun RenXiaofeng Yu
This paper investigates the relationship between employees＇ perception of work-family balance practices and work-family conflicts. It examines the role of challenge stress and hindrance stress as moderators. Based on survey data collected from 841 civil servants in Beijing, we found that perceived work-family balance practices may reduce work-family conflict, while challenge and hindrance work stresses were positively related to work-family conflict. In addition, challenge and hindrance stresses differentially moderated the relationship between perceived work-family practices and work-family conflict. When challenge stress is high then workffamily balance practices will reduce work-family conflict. However, under high hindrance stress, work-family balance practices will serve to reduce work-family conflict less. More detailed analysis of the configurational dimensions of work-family balance practices （work flexibility, and employee and family wellness care） are also tested. This study provides additional insight into the management of work-family interfaces and offers ideas for future research.
Xiaoxi ChangYu ZhouChenxi WangCarmen de Pablos Heredero
Hydraulic fracturing is one of the most important techniques for enhancing oil/gas production.The permeability-based hydraulic fracture(PHF)model,which is based on the smeared-crack method and considers the interaction between the pore pressure and solid phase,is adopted in the present study for a fully-coupled simulation of the hydraulic fracture in a heterogeneous rock formation.The level set method(LSM),which is used to describe the distribution of material properties of heterogeneous rocks,is coupled with the PHF model.Using the coupled PHF–LSM model,a series of finite element method(FEM)simulations are carried out to investigate the characteristics of a hydraulic fracture(e.g.,the breakdown pressure and fracture propagation)in heterogeneous rocks.Three types of heterogeneous rocks are examined:layered rock,rock with distributed inclusions,and rock with random spatial variations in the material properties.The results of the numerical simulations show that the coupled PHF–LSM model can describe the material interface without changing the FEM mesh used to discretize the physical domain.Further,the model effectively simulates hydraulic-fracturing problems for various heterogeneous rocks.
Ming LiPeijun GuoDieter F.E.StolleLi LiangYitao Shi
Key-dependent message （KDM） security is an important security issue that has attracted much research in recent years. In this paper, we present a new construction of the symmetric encryption scheme in the the ideal cipher model （ICM）; we prove that our scheme is KDM secure against active attacks with respect to arbitrary polynomialtime challenge functions. Our main idea is to introduce a universal hash function （UHF） h as a random value for each encrypfion, and then use s = h（sk） as the key of the ideal cipher F, where sk is the private key of our symmetric encryption scheme. Although many other schemes that are secure against KDM attacks have already been proposed, in both the ideal standard models, the much more significance of our paper is the simplicity in which we implement KDM security against active attacks.
Qiqi LAI Yuan CHEN Yupu HU Baocang WANG Mingming JIANG
Industrial symbiosis is the quintessential characteristic of an eco-industrial park. To divide parks into different types, previous studies mostly focused on qualitative judgments, and failed to use metrics to conduct quantitative research on the intemal structural or functional characteristics of a park. To analyze a park＇s structural attributes, a range of metrics from network analysis have been applied, but few researchers have compared two or more symbioses using multiple metrics. In this study, we used two metrics （density and network degree centraliza- tion） to compare the degrees of completeness and dependence of eight diverse but representative industrial symbiosis networks. Through the combination of the two metrics, we divided the networks into three types： weak completeness, and two forms of strong completeness, namely ＂anchor tenant＂ mutualism and ＂equality-oriented＂ mutualism. The results showed that the networks with a weak degree of completeness were sparse and had few connections among nodes; for ＂anchor tenant＂ mutualism, the degree of completeness was relatively high, but the affiliated members were too dependent on core members; and the members in ＂equality-oriented＂ mutualism had equal roles, with diverse and flexible symbiotic paths. These results revealed some of the systems＇ internal structure and how different structures influenced the exchanges of materials, energy, and knowledge among members of a system, thereby providing insights into threats that may destabilize the network. Based on this analysis, we provide examples of the advantages and effectiveness of recent improvement projects in a typical Chinese eco-industrial park （Shandong Lubei）.
Yan ZHANGHongmei ZHENGHan SHIXiangyi YUGengyuan LIUMeirong SUYating LIYingying CHAI
During past few years,the construction of fluorescent metallacycles featuring the fluorescenceresonance energy transfer behavior has attracted extensive attention due to their diverse applications such as real-time monitoring the dynamics of coordination-driven self-assembly,photoswitching fluorescence-resonance energy transfer,and light-controlled generation of singlet oxygen for cancer therapy.This review focuses on the recent advances on the design principles,preparation methods,optical properties,and the wide applications of fluorescent metallacycles with the FRET property.
To ensure the authenticity and integrity of bundles, the in-transit PDUs of bundle protocol （BP） in space delay/disruption-tolerant networks （DTNs）, the bundle security protocol specification （IRTF RFC6257） suggested using a digital signature directly over each bundle. However, when bundle fragment services are needed, this mechanism suffers from heavy computational costs, bandwidth overheads and energy consumption. In this paper, we address the fragment authentication issue for BP by exploiting the combination of RS error correction and erasure codes with the help of batch transmission characteristic of DTNs. The RS error correction and erasure codes are adopted to allow the receivers to locate the false/injected fragments and reconstruct the only one signature shared by all fragments of a bundle, even if some other fragments are lost or routed to a different path. Getting only partial authentic fragments, a DTN node is able to detect and filter the false/injected fragments, and authenticate the origin of a bundle as well. Such an approach tolerates high delays, unexpected link disruption and the BP nature of routing fragments of the same bundle possibly via different paths. The performance analysis demonstrates that both of our schemes, which follow our generic idea based on RS codes, significantly reduce bandwidth overheads and computational costs as compared to the prior works.
We study the effects of film thickness on lattice parameters, direct band gap and photovoltaic outputs in the sol-gel derived BiFeO3 thin films. With the change of the film thickness, the great transitions will take place in the preferred orientation and lattice parameters. Furthermore, the photovoltaic outputs are significantly dependent on the film thickness. The results show that the open circuit voltage gradually increases and the short circuit current reciprocally decreases with the increase of film thickness. In particular, we demonstrate for the first time that there are tunable photovoltaic outputs with external electric field polarization switching in the polycrystalline BiFeO3 film, which is critical for the future device applications based on the photovoltaic properties of BiFeO3 films.
We investigate the transport properties of a pair of Majorana bound states in a T-shaped junction, where two normal leads are coupled with an identical Majorana bound state. Both the scattering matrix and the recursive Green function method show that the peak value of the differential conductance （Gpeak） in units of e2/h and the shot noise Fano factor in the zero bias limit （F0）, which are measured at the same lead and zero temperature, satisfy a linear relation as F0=1＋Gpeak/2, independent of the magnitude or symmetry of the coupling strengths to the leads. Therefore, combined measurements of the differential conductance and shot noise in the T-shaped geometry can serve as a characteristic signature in probing Majorana bound states.
