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Straw fiber mulch film is a promising alternative to petroleum-based plastic mulching film. The optimal combination of process parameters during the manufacturing process of the wheat straw fiber-based plant fiber film (hereinafter referred to as film), was studied via a five-factor and five-level central composite design methodology. Response surface methodology was used to analyze the effects of sizing agent content, wet strength agent mass fraction, basis weight, KP pulp mixing ratio, and beating degree of wheat straw fiber on the dry tensile index, wet tensile index, and degradation time. The optimal parameters were as follows: a sizing agent content of 2.0%, a wet strength agent mass fraction of 60%, a beating degree of wheat straw fiber of 60 °SR, a basis weight of 54.6 to 60.8 g/m2, and a KP pulp mixing ratio of 37.6% to 44.7%. These parameters achieved the desired physical properties, i.e., a degradation time of 55 to 65 d, a dry tensile index of 10 to 12 N·m/g, and a wet tensile index 3.5 to 5.5 N·m/g. With the optimal manufacturing parameters, straw mulch film would meet the demands for agriculture.

The amination and alkenylation of the C(sp3)–H bond at the N-α position of secondary benzamides were both realized by using N-hydroxyphthalimide (NHPI) imidate esters as substrates under a dual photoredox-hydrogen atom transfer (HAT) catalyst.

A facile synthetic method for the C(sp2)–H bond functionalization of unactivated alkenes via visible-light-induced photoredox-quinuclidine dual catalysis and distal heteroaryl ipso-migration has been realized under mild conditions.

A strategy for overcoming the limitation of the Morita–Baylis–Hillman (MBH) reaction, which is only applicable to electron-deficient olefins, has been achieved via visible-light induced photoredox catalysis in this report.

The site selective C(sp

N-Hydroxyphthalimide (NHPI) imidate esters were designed and used as amidyl radical precursors in the visible light photocatalyzed C–H amidation of heteroarenes for the first time. The reactions can be conducted under simple and mild conditions with a broad scope of electron-rich heteroarenes and NHPI esters, affording the desired amidation products in moderate to good yields. Moreover, the mechanistic paradigm has been clarified on the basis of Stern–Volmer analysis and the measurement of redox potentials.

Two 3D finite element models are established to analyze the mechanical response of road construction and solve the problem in which the actual fatigue life of the overlay is significantly shorter than the designed value. The first model is composite pavement with multiple overlays, whereas the second model is pavement overlaid with the same thickness of asphalt concrete. Calculation result indicates that interlaminar bonding condition significantly affects shear stress and tensile strain, and the value calculated by the second model is smaller than that calculated by the first model, which may lead to unsafe design. The following conclusions can be drawn based on the tendency of interlayer shear to form along the direction of road depth. (1) The interlaminar shear of old pavement decreases when overlaid with asphalt concrete, whereas maximum shear stress always occurs at the bottom of the surface layer. (2) When pavement overlay frequency is increased, the interlaminar shear value of the surface layer will be increased. The value of interlayer shear stress mutation increases with the frequency of overlay. The simulation results show that the service life of asphalt overlay decreases with the frequency of overlay, which indicates that overlaying asphalt cannot improve the stress state of the surface layer. By contrast, the comprehensive influences of interlaminar bonding condition and composite load will increase surface stress, which may eventually intensify surface damage.

N2-selective autocatalytic ditriazolylation reactions of cyclopropenones and tropone with N1-sulfonyl-1,2,3-triazoles were reported for the first time. In contrast to previous methods for preparing N2-substituted bis(1,2,3-triazolyl) compounds, the reaction achieved ditriazolylation in one step under simple and user-friendly conditions with a wide range of substrate scope. A plausible mechanism has been proposed relying on preliminary mechanistic investigations.

A mix-net is an important cryptographic tool in schemes requiring anonymity of messages, such as in secure e-voting and e-auction schemes. In this paper, we present a novel mix-net protocol which achieves stronger security and satisfies both public verifiability and sender verifiability. Our mix-net is constructed based on Wikstrom's scheme and strengthens its se-curity by introducing an improved key generation procedure and proposing a new method for constructing zero knowledge proof of secret shuffle. It is proved to be CCA-secure under the assumption of random oracle. Compared with previous mix-net schemes which are CCA-secure, the proposed protocol does not require any trusted center, and incurs fewer inter-actions between servers which resulting in a lower computation and communication complexity.

Network coding has been shown to have a lot of positive effects on networks. However, its mixing nature contributes to its vulnerability to pollution attacks. Two kinds of schemes, homomorphic MAC based schemes and homomorphic signature based schemes, have been proposed to achieve secure random linear network coding. In this paper, we present POND, a novel protocol using RIPPLE transmission protocol and homomorphic signature in the areas near and far from the source respectively. POND theoretically achieves better overall communication efficiency. And by utilizing neoteric symmetric key distribution method, it is immune to key related attacks. To the best of our knowledge, our work is the first solution which uses different authentication schemes in different parts of a network for network coding.

Electrocoagulation (EC) has been proven by a substantial number of studies to be an efficient technology to remove organic pollutants from wastewater. Nevertheless, the high energy consumption of this technology inhibits its extensive application. The objective of this work is to investigate the feasibility of electrical energy conservation and high efficiency by using Pulse Electrocoagulation (PE). PE, a combination of a pulsing technique and EC, was proposed in an attempt to treat the dye wastewater. The results demonstrated that PE, as compared with DCE (direct current electrocoagulation), resulted in up to 51.66% energy conservation by using two iron electrodes as anode and cathode. Moreover, this high energy conservation was obtained during a high level of treatment efficiency: 99.62% of color removal and 91.15% of COD removal for 1000 mg L-1 4BS solution in a short electrolyzing time of 15 mins.

We present a robust disaster recovery system model according to the requests of disaster recovery talent of a key e-government project of China. The model strengthens the safe communication ability and guarantees the secure command on disaster recovery. It introduces a self-supervision power to watch the integrality and security of the disaster recovery system itself. It makes the use, management, and maintenance of the disaster recovery system much easier through the real-time visible platform. This model suits security-critical environments for owning the features of security, robustness, and controllability. It has guided the construction of an e-government disaster recovery system of China.

In this paper, we devise a novel anonymous voting protocol based on bilinear pairings. This protocol can be used by a group of participants to vote for one or more resolutions under the decentralized condition (boardroom voting), at the meantime preserving the privacy of participants. More specifically, in the session key set-up phase, every participant just need to broadcast a single message containing an ephemeral public key and a zero-knowledge proof. In the commitment phase, participants should broadcast the commitment of their votes although the actual votes are not revealed. After that, in the voting phase, every participant should encrypts his or her vote by combining these public keys and his secret session key, and then broadcast it to others. Finally, the voting result can be recovered by multiplying all the votes together. The advantage of our protocol over others lies in the fact that once the session keys have been established, they can be used repeatedly over multiple commitment and voting phases. So it requires just two rounds of broadcasting in every voting process after the first one, rendering it pretty good in terms of round efficiency. More precisely, if a group need to vote for several resolutions in one meeting, our protocol would involve less computational load and bandwidth usage in every vote. In fact, it is better than all the other techniques known. Our protocol is provably secure under the Decision Bilinear Diffie-Hellman assumption and random oracle assumption.

Reusable anonymous return channels proposed by Golle and Jakobsson allow any recipient of one of the anonymous messages in a mix net to send back one or more replies directly. Yet their protocol has an obvious efficiency problem caused by multiple rounds of message processing. In this paper, we introduce a technique which is based on universal re-encryption and increases the total efficiency of reusable anonymous return channels. Our protocol retains all the significant attributes of the reusable channels, known as compos ability, reusability, transferability and compatibility. And it reduces the processing rounds of a message so as to increase efficiency. Moreover, it produces some new important properties. When using our protocol, even if all the servers in our system are corrupted, they can not gain the information of message content and our system can not be easily used as a decryption oracle. We also improve the efficiency of our original protocol when processing long messages and present a hybrid construction for it. Using Pohlig-Hellman, a message is much shorter in our hybrid construction than it is in our primary construction. As a result, the larger a message is, the more efficient our hybrid construction becomes.

Mix-net is a cryptographic technique that is used to hide the origin of messages in computer network communications. The optimistic mix-net proposed by Golle et al. is a very practical and efficient construction which has a very fast mixing process when all players behave honestly. A new type of relation attack on Golle's optimistic mix-net and its modified editions is presented in this paper. In particular a malicious mix server can break any given user's anonymity in previous mix- sessions by using current session as a decryption oracle at the cost of being accused of cheating. The attack suggests that the optimist mix-net must use different keys in each mix-session and this demerit would deliver a significant blow to its practical value.

A mix network is a cryptographic construction for anonymous communications. In addition to anonymity, a reputable mix network first defined by Golle offers a reputation property: the mix-net can prove that every message it outputs corresponds to an input submitted by a user without revealing which input. This property can shield the mix-net from liability in the event that an output message is objectionable or illegal. In this work we analyze two reputable ElGamal based mix-net schemes proposed by Golle and present two active attacks for them. Our attacks rely on the homomorphism properties of RSA signature and ElGamal cryptosystem and can break the reputation properties of those schemes. We also show how to counter our attacks by using secure hash functions.