New Identity Based Proxy Re-Encryption Scheme from Lattices

Identity-Based Proxy Re-Encryption (IB-PRE) allows a semi-trusted proxy to convert the ciphertext encrypted under Alice’s identity into Bob’s ciphertext of the same message without leaking plaintext. Lattice-based cryptography enjoys potential resistance to quantum analysis and low computational complexity. A multi-hop and unidirectional IB-PRE from lattices is presented. We split the functions of decryption and ciphertext transformation separately, and design the double private keys mechanism, where two keys are generated for each user, one key is used to decrypt the ciphertext by Pre-Image Sampling technique, and the other is used to generate the re-encryption key by Bonsai Trees technique. The generation of the re-encryption key is non-interactive and collusion resistant. Moreover, its IND-sID-CPA security over the decisional Learning With Errors (LWE) assumption under the standard model is proved. Compared with some previous IBPRE schemes from Bilinear Pairings, the format of transformed ciphertext in our scheme remains unchanged, furthermore, it can also resist quantum analysis. Compared with some existing IB-PRE schemes from lattices with similar properties, the space of the message in our scheme is a vector of length l and the encryption process remains a lower encryption blowup factor. At last, a proof-of-concept implementation is provided.

High speed cutting of AZ31 magnesium alloy

Using LBR-370 numerical control lathe,high speed cutting was applied to AZ31 magnesium alloy.The influence of cutting parameters on microstructure,surface roughness and machining hardening were investigated by using the methods of single factor and orthogonal experiment.The results show that the cutting parameters have an important effect on microstructure,surface roughness and machine hardening.The depth of stress layer,roughness and hardening present a declining tendency with the increase of the cutting speed and also increase with the augment of the cutting depth and feed rate.Moreover,we established a prediction model of the roughness,which has an important guidance on actual machining process of magnesium alloy.

Surgical treatment of large pheochromocytoma(>6 cm):A 10-year single-center experience

Objective:Clinical practice guidelines recommend open adrenalectomy(OA)for large pheochromocytoma(LPCC)>6 cm in size.Although laparoscopic adrenalectomy(LA)for the treatment of LPCC has been reported,its role remains unclear.This study aimed to compare the effectiveness of LA and OA,and summary the surgical treatment experience.Methods:Data concerning LPCC,from January 2010 to June 2019 of a single institution,were retrospectively reviewed.Altogether 82 patients with a tumor larger than 6 cm were included(52 patients in LA group and 30 patients in OA group).Groups were balanced by propensity score matching(PSM)into 15 pairs.Patients’demographics,preoperative characteristics,and prognosis were analyzed.Results:Before PSM,the OA group had larger tumor sizes(median[interquartile range,IQR]:8.9[7.3-10.3]vs.7.2[6.7-8.0]cm;p=0.000)and higher vanillylmandelic acid level(median[IQR]:114.3[67.8-326.4]vs.66.6[37.8-145.8]μmol/24 h;p=0.004)and needed a higher cumulative dose of prazosin(median[IQR]:83.5[37.0-154.0]vs.38.0[21.0-81.0]mg;p=0.028).After PSM,the baseline data showed no significant differences between both groups.The LA group had relatively more stable blood pressure in surgery,with a lower fluctuation of systolic blood pressure(mean±standard deviation[SD]:70.9±25.1 vs.107.4±46.2 mmHg,p=0.012)and a lower percentage of hemodynamic instability(46.7%vs.86.7%,p=0.020).The LA group had shorter postoperative hospital stays(mean±SD:6.4±2.7 vs.10.1±3.4 days;p=0.003)than the OA group.Differences regarding metastasis rate(6.7%vs.0,p=1.000)were not statistically significant between LA and OA groups.The median(IQR)follow-up time of 82 patients was 72.5(47.0-103.5)months.Binary logistic regression showed that right-side tumors or those>8 cm in size were independent risk factors of OA.Conclusion:LA is a safe,minimally invasive procedure for LPCC and has relatively better perioperative characteristics in large medical centers.Patients with tumors on the right side or larger than 8 cm are more likely to undergo OA initially.

Review on loss prevention of chemical reaction thermal runaway:Principles and application

Reaction thermal runaway has been extensively characterized as a major hazard for fine chemical industry.It is necessary to develop safety technologies for the control of reaction thermal runaway in emergencies and mitigating the subsequent hazards.To date,literature review on the loss prevention methods of chemical reaction thermal runaway is insufficient.In this paper,a comprehensive review is delivered to outline the progress of emergency response technologies for reaction thermal runaway in recent years,major principles and potential applications of those loss prevention methods.It is expected that this review article has certain reference value for the further understanding of thermal runaway,the design of mitigation systems,and the formulation of emergency response strategy for runaway reactions.

Approaching 19%efficiency and stable binary polymer solar cells enabled by a solidification strategy of solvent additive

Additives play a crucial role in enhancing the photovoltaic performance of polymer solar cells(PSCs).However,the typical additives used to optimize blend morphology of PSCs are still high boiling-point solvents,while their trace residues may reduce device stability.Herein,an effective strategy of“solidification of solvent additive(SSA)”has been developed to convert additive from liquid to solid,by introducing a covalent bond into low-cost solvent diphenyl sulfide(DPS)to synthesize solid dibenzothiophene(DBT)in one-step,which achieves optimized morphology thus promoting efficiency and device stability.Owing to the fine planarity and volatilization of DBT,the DBT-processed films achieve ordered molecular crystallinity and suitable phase separation compared to the additive-free or DPS-treated ones.Importantly,the DBT-processed device also possesses improved light absorption,enhanced charge transport,and thus a champion efficiency of 17.9%is achieved in the PM6:Y6-based PSCs with an excellent additive component tolerance,reproducibility,and stability.Additionally,the DBT-processed PM6:L8-BO-based PSCs are further fabricated to study the universality of SSA strategy,offering an impressive efficiency approaching19%as one of the highest values in binary PSCs.In conclusion,this article developed a promising strategy named SSA to boost efficiency and improve stability of PSCs.

Hot Compression Mechanical Behavior of Solution Heat‑Treated and Pre‑aged Mg–Zn–Gd–Er Alloys

The mechanical behavior of solution heat-treated and pre-aged Mg–6Zn–1Gd–1Er alloys during hot compression(from 180 to 330℃)has been investigated.The results showed that the flow stress curves of the pre-aged sample(PAS)intersected with that of the solution heat-treated sample(SHTS)during hot compression.At 180℃,when the true strain is 0.27 and 0.47,the PAS showed larger and smaller stress(210.80 MPa vs.207.58 MPa and 205.67 MPa vs.207.93 MPa)than the SHTS,respectively.These phenomena were due to the stronger interaction of W phase and dislocations/twins under the strain of 0.27,while dynamic recrystallization softening occurred under the strain of 0.47.When the temperature increased to 330℃,the flow stress of PAS and SHTS showed an opposite trend to that of 180℃.Continuous dynamic recrystallization and particle stimulated nucleation based on slip operations are the main deformation mechanisms under 330℃.At the true strain is 0.33 and 0.53,the PAS has smaller and larger stress(61.32 MPa vs.63.69 MPa and 58.75 MPa vs.57.09 MPa)than the SHTS,respectively.The increasing deformation resistance of dynamic precipitation improved the flow stress under smaller strain and dynamic recrystallization decreased the flow stress under high strain,which resulted the opposite phenomena of SHTS.

Enhanced Li+migration in solid polymer electrolyte driven by anion-containing polymer-chains

Li-ion batteries with solid polymer electrolytes(SPEs)are safer than conventional liquid electrolytes due to the absence of highly flammable liquid electrolytes.However,their performance is limited by the poor Li+transport in SPEs at room temperature.Anion-containing polymer-chains incorporated SPEs(ASPEs)are therefore developed to enhance Li^(+) diffusion kinetics.Herein,we propose a novel and feasible strategy to incorporate the anion-containing polymer-chains,such as lithiated perfluorinated sulfonic acid(PFSA),into polyvinylidene fluoride(PVDF)polymer-based SPEs.The immobile anion groups from the PFSA-chains impede the migration of mobile anion groups dissociated from the Li salt.The transference number is thus raised from∼0.3 to 0.52 with the introduction of anion-containing polymer-chains into SPEs.The electrostatic repulsion among anion-containing chains also reduces the close chain stacking and brings 159%increase in the ionic conductivity to 0.83×10^(−3) S/cm at 30℃ in contrast with the pure PVDF-based SPE.In addition,LiFeO_(4)/Li batteries with ASPEs exhibit 55%capacity boost at 0.5 C in contrast to the capacity of batteries with pure-PVDF SPEs,and also offer more than 1000 charge/discharge cycles.Our research findings potentially offer a facile strategy to design thermal stable SPEs with superior Li^(+) transport behaviors towards developing high-performance SPEs-based batteries.

高温陶瓷过滤管性能退化建模及实时寿命预测

高温陶瓷过滤管由内部孔径较大的支撑体和外部孔径较小的过滤膜双层结构构成,在实际应用中,存在大量粒径较小的粉尘颗粒,会穿过过滤膜沉积到支撑体内部,脉冲反吹无法有效清除.因支撑体内颗粒沉积及管壁外残余粉尘层不断压缩,使陶瓷过滤管渗透率不断下降,残余压降逐渐增加。本工作基于高温陶瓷过滤管壁内颗粒沉积特性及残余粉尘层压缩不可直接观测的特点,结合贝叶斯估计理论,利用过滤管运行期间采集的残余压降数据,提出一种基于状态空间模型的过滤管性能退化建模方法。该方法能融入最新采集到的残余压降数据,实时对模型参数进行更新,可对陶瓷过滤管的剩余寿命进行实时预测,同时对陶瓷过滤管剩余寿命的失效概率密度分布及陶瓷过滤管的退化状态变化率进行预测。对某高温试验装置及壳牌煤气化装置中的陶瓷过滤管残余压降分析表明,预测剩余寿命准确率随残余压降数据增加而逐渐增加,后期预测准确率高于95%,且陶瓷过滤管退化状态变化率逐渐变小,与陶瓷过滤管残余压降前期增加快后期增加慢的现象一致。

On the Linear Complexity of New Generalized Cyclotomic Binary Sequences of Order Two and Period pqr

Periodic sequences over finite fields, constructed by classical cyclotomic classes and generalized cyclotomic classes, have good pseudorandom properties. The linear complexity of a period sequence plays a fundamental role in the randomness of sequences. Let p, q, and r be distinct odd primes with gcd（p-1, q-1 ）=gcd（p- 1, r-1）=gcd（q-1, r-1）=2. In this paper, a new class of generalized cyclotomic sequence with respect to pqr over GF（2） is constructed by finding a special characteristic set. In addition, we determine its linear complexity using cyclotomic theory. Our results show that these sequences have high linear complexity, which means they can resist linear attacks.

Novel Video Steganography Algorithm Based on Secret Sharing and Error-Correcting Code for H.264/AVC

In this paper, we analyze the video steganography technique, which is used to ensure national security and the confidentiality of the information of governmental agencies and enterprises. Videos may be used to transmit secrets and conduct covert communication. As such, we present an algorithm based on a secret sharing scheme and an Error-Correcting Code（ECC）, which combines Grey Relational Analysis（GRA） with a partition mode in video compression standard H.264/AVC. First, we process secret information by secret sharing, and then use an ECC to process the obtained information. Moreover, we choose the Discrete Cosine Transform（DCT） blocks using GRA, and then use rules to hide the pretreated information in DCT coefficients of the video frames. Experimental results indicate that our algorithm has good invisibility, better robustness, good anti-steganalysis ability, and little influence on the bit rate of the video carrier. In addition, the bit error rate is low after attacks such as noise, filtering,or frame loss in the simulation environment.

Effect of Ti（lll） Surface Defects on the Process of Photocatalytic Reduction of Hexavalent Chromium

In this paper, the process of photocatalytic reduction of hexavalent chromium was investigated over Ti3＋- modified TiO2 photocatalysts. The Ti3＋ surface defects were repaired by annealing as-prepared sample at different temperatures to control the amount of Ti3＋ sites. The samples were characterized by SEM, XRD, BET, UV-Vis absorption, EPR and XPS. The results showed Ti3＋ defects were successfully doped in TiO2. The surface selective adsorption of hexavalent chromium [Cr2072 （Cr（VI））] and the desorption of trivalent chromium [Cr3＋ （Cr（III））] were investigated during the process ofphotocatalytic reduction positive charges due to more Ti3＋ defects on the surface show a Accordingly, the surface positive reduction of Cr（VI）. charges controlled by the Ti3＋ Zeta potential results presented that the increased significant improvement for adsorption of Cr（VI）. defects play important roles in the photocatalytic