Search

For the degradation of chitosan, a novel physical method of self-resonating cavitation with strong cavitation effects was investigated in this paper. The effects of initial concentration, pH, temperature, inlet pressure and cavitation time on the degradation efficiency of chitosan were evaluated. It was found that the degradation efficiency was positively correlated with temperature and cavitation time, but was negatively correlated with the solution concentration. The degradation efficiency was maximized at pH of 4.4 and inlet pressure of 0.4 MPa. Under the experimental conditions, the intrinsic viscosity of chitosan solution was reduced by 92.2%, which was twice as high as the degradation efficiency where a Venturi tube cavitator was used. The viscosity-average molecular weights of initial and degraded chitosan were 651 and 104 kD, respectively. The deacetylation degree of chitosan slightly decreased from 89.34% to 88.05%. Structures and polydispersity of initial and degraded chitosan were measured by Fourier-transform infrared spectroscopy (FT-IR), nuclear magnetic resonance hydrogen spectroscopy (1H NMR), X-ray diffraction (XRD) and gel permeation chromatography (GPC). The results showed that the degradation process did not change the natural structure of chitosan. XRD peaks of the original chitosan were observed at 2θ of 9.59° and 20.00°, and the one at 2θ of 20.00° was obviously weakened after the degradation process, which indicated that the crystallinity of chitosan decreased significantly after the degradation. The polydispersity index of chitosan samples decreased from 3.17 to 2.75, indicating that the molecular-weight distribution of products after the degradation was more concentrated. The results proved that self-resonating cavitation prompted the degradation of chitosan and could reduce the polydispersity of the products for the production of oligochitosan with homogeneous molecular weights.

The combination of 5G technology and the industrial Internet of things (IIoT) makes it possible to realize the interconnection of all things. Still, it also increases the risk of attacks such as large-scale DDoS attacks and IP spoofing attacks. Threat intelligence is a collection of information causing potential and nonpotential harm to the industrial Internet. Extracting network security entities and their relationships from threat intelligence text and constructing structured threat intelligence information are particularly important for IIoT security protection. However, threat intelligence is mostly text reports, which means the value information needs to be extracted manually by security analysts, and it is highly dependent on personnel experience. Therefore, this study proposes an IIoT threat intelligence analysis method based on feature weighting and BERT-BiGRU. In this method, BERT-BiGRU is used to classify attack behavior and attack strategy. Then, the attack behavior is weighted to make the classified result more accurate according to the relationship between attack strategy and attack behavior in ATT&CK for ICS knowledge. Finally, the possibility of attack and the harm degree of attack are calculated to form the threat value of the attack. The security analysts can judge the emergency response sequence by the threat value to improve the accuracy and efficiency of emergency response. The results indicate that the proposed method in this study is more accurate than the other standard methods and is more suitable for the unstructured threat intelligence analysis of IIoT.

Knowledge graph simple question answering (KGSQA) aims on answering natural language questions by the lookup of a single fact over a knowledge graph. As one of the core tasks in the scenarios, relation extraction is critical for the quality of final answers. To improve the accuracy of relation extraction in KGSQA, in this paper, we propose a new deep neural network model called TEBC-Net, which is constructed based on the combination of Transformer Encoder, BiLSTM and CNN Net in a seamless way. We give the detailed design of our approach and have conducted an experimental evaluation with a benchmark test. Our results demonstrate that TEBC-Net can achieve higher accuracy on relation extraction and question answering tasks in KGSQA, compared to some current methods including the state-of-the-art.

Hydrodynamic cavitation is an effective method for chitosan degradation, of which the mechanism directly determines the molecular weight distribution of degradation products. In this study, based on the Monte Carlo simulation and experimental results, the mechanism of chitosan degradation with hydrodynamic cavitation and molecular weight distribution of products were analyzed. The results showed that the algorithm established in the simulation could effectively analyze degradation mechanism and the factors that influenced degradation mechanism and molecular weight distribution of products. The degradation with hydrodynamic cavitation was caused by chemical and mechanical effects, of which the former dominated the degradation process. The outlet and inlet angles and throat length of the cavitator had major and minor influences on the degradation pattern, respectively. The chemical effect led to random cuts resulting in wide distribution of the products, while the mechanical effect led to central cuts resulting in narrow distribution of the products. With more central cuts, the slide-shaped molecular weight distribution curve of degradation products was gradually transferred into a bell-shaped curve. These results provide instructions for researches on the molecular weight distribution of chitosan products degraded with hydrodynamic cavitation.

Through the freeze-thaw cycle test, the damage characteristics of basalt fiber cement solidified aeolian sand with different basalt fiber and cement content, different freeze-thaw cycles and curing age were analyzed. The test results show that with the increase of the basalt fiber content, the damage degree of the basalt fiber cement solidified aeolian sand under the action of freeze-thaw cycle first decreases and then increases, and the damage degree is minimum when the basalt fiber content is 0.5%; The 90-day-old specimens were more resistant to freeze-thaw damage than the 28-day specimens. By establishing the damage model of unconfined compressive strength loss rate and freezing and thawing times of basalt fiber-solidified aeolian sand, it was found that it obeyed the quadratic polynomial change trend, and the fitting accuracy was greater than 0.9. The gray entropy analysis method was used to find that the amount of cement had the greatest influence on the mass loss rate and unconfined compressive strength of basalt fiber-solidified aeolian sand specimens.

In order to study the basalt fiber in the road with the performance, the test of matrix asphalt concrete, basalt fiber reinforced asphalt concrete and the SBS modified asphalt concrete applying ultraviolet aging, high and low temperature alternating cycle change, after the freeze-thaw cycle and salt freezing and thawing cycle road environment for rutting test, low-temperature bending test and immersion Marshall test. The test results show that basalt fiber plays an important role in improving the high-temperature stability, low-temperature crack resistance and water stability of asphalt concrete under different road conditions. The degree of influence of pavement environment on the deterioration of pavement performance of basalt fiber asphalt concrete is as follows: ultraviolet aging > high and low temperature alternating cycle > freeze-thaw cycle > salt freeze-thaw cycle.

Formal analysis is used to find out flaws of cryptographic protocols. A formal analysis method with reasoning for cryptographic protocols has been proposed. In the method, behaviors of participants and behaviors of an intruder are used as premises of forward reasoning to deduce formulas, then analysts check whether the deduced formulas are related to flaws. However, the method only can detect the flaws related to confidentiality and authentication but is unable to detect the flaws related to non-repudiation and fairness. This paper proposes an extension of the formal analysis method with reasoning, which can deal with the flaws related to non-repudiation and fairness. This paper also shows a case study of flaw detection for non-repudiation and fairness in ISI protocol with the proposed method. The result shows that the proposed method is effective to find out flaws that related to the two security properties above.

The AC-16 asphalt concrete with A grade 90# asphalt and A grade 90# asphalt mixed with 0.3% basalt fiber as the binder was taken as the research object, passing the rutting test, trabecular bending test and freeze-thaw splitting test. The high temperature stability, low temperature crack resistance and water stability of the two asphalt mixtures after different environmental impact factors showed that the dynamic stability, maximum bending strain and residual strength ratio of the basalt fiber reinforced asphalt concrete were significantly higher. In the matrix asphalt concrete. The dynamic stability of basalt fiber asphalt concrete compared with matrix asphalt concrete increased by 15.79%, 14.7%, 16.51%, 18.18%, respectively, after environmental influence factors and UV, high and low temperature alternating, freeze-thaw and salt freezing environment. 17.95%; after the same environmental action, the maximum bending strain of basalt fiber asphalt concrete increased by 14.99%, 30.57%, 18.77%, 19.29%, 15.94%, respectively; the residual strength ratio increased by 3.82%, 5.61%, 8.82%, 10.76%, 10.36%; and the accuracy of the test data was verified microscopically from the action of basalt fiber by scanning electron microscopy.

Load crack is one of the main failure forms of asphalt concrete pavement. Basalt fiber has become an important research direction of road fiber modifier. However, the self-healing performance research of basalt fiber asphalt mixture under different road environment factors are rarely. In this paper, the self-healing performance of asphalt pavement in different road environments is studied by combining the self-healing properties of asphalt and the crack resistance of fiber materials. The self-healing test of basalt fiber asphalt concrete was carried out after long and short aging, ultraviolet aging, snow melting and freeze-thaw cycles treatment. By using the damage rate as the evaluation index, the self-healing characteristics of basalt asphalt pavement were analyzed by the method of “fatigue-self-healing - fatigue” under the influence of different road environment. The experiment also compared the self-healing properties with SBS modified asphalt and matrix asphalt and explained the mechanism of basalt fiber mixture self - healing by electron microscope. The results show that the addition of basalt fiber can greatly improve the self-healing level of asphalt concrete under various road conditions.

Formal analysis is used to find out flaws of cryptographic protocols. A formal analysis method with reasoning for cryptographic protocols has been proposed. In the method, forward reasoning is used to deduce flaws or situations related to flaws from formalized specifications of cryptographic protocols. Analysts of cryptographic protocols pick up deduced results related to flaws from results of forward reasoning according to some criteria. However, there is no study about the criteria for what are flaws that can be applied to various cryptographic protocols. This paper presents fine-grained security properties that cryptographic protocols should satisfy in order to clarify the criteria. The paper shows the enumerated security properties are correct and valid through analyzing some cryptographic protocols.

Many cryptographic protocols have been proposed, and many studies of them have been done. However, there is no study to identify constituent elements of cryptographic protocols that are elements of the protocols consist of. The constituent elements can be used for the basis of classification of already proposed cryptographic protocols, the basis of prediction of new cryptographic protocols, and the basis of formal verification for cryptographic protocols. This paper presents primitive constituent element of cryptographic protocols that is an element so that cryptographic protocol cannot accomplish its original tasks without it.

To investigate the effects of transcatheter arterial chemoembolization (TACE) combined with precise radiation therapy (RT) on p53 gene expression and prognosis of patients with hepatocellular carcinoma (HCC). A total of 80 patients with unresectable HCC treated in the First People's Hospital of Qinhuangdao from March 2009 to March 2015 were randomly divided into TACE group (n=40) and TACE + RT group (n=40). Enzyme-linked immunosorbent assay (ELISA) was used to detect the levels of p53 in both groups before and after treatment. The biochemical indexes of liver function [α-fetoprotein (AFP), alanine aminotransferase (ALT) and γ-glutamyl transferase (GGT)] were detected. Moreover, adverse reactions were compared between the two groups of patients, the short-term therapeutic effect was evaluated, and effects of two treatment methods on progression-free survival (PFS) and overall survival (OS) of patients were detected. There were no statistically significant differences in clinical data between the two groups of patients (P>0.05). The p53 protein levels were significantly downregulated in both treatment methods, and it was decreased more significantly in TACE + RT group than that in TACE group (P

Formal analysis of cryptographic protocols is to find out flaws in the protocols by various formal methods. Some supporting tools for formal analysis of cryptographic protocols have been proposed and applied, but the tools failed to support the whole processes of formal analysis automatically. Therefore, a supporting environment which can support formal analysis automatically is needed for analysts. This paper presents the first supporting environment for formal analysis of cryptographic protocols.

Formal analysis of protocols is to find out flaws in cryptographic protocols by formal method. In formal analysis methods with proving such as theorem proving and model checking, analysts must set possible attacks as targets, and then verify whether these attacks succeed or not. However, it's impossible to enumerate all attacks so that flaws may be not detected. As an alternative way, a formal analysis method with reasoning has been proposed, but it can only be applied to key exchange protocols. This paper presents a formal analysis method with reasoning for various cryptographic protocols. By succeeding in detecting flaws of splitting protocols, we show that the proposed method is effective for various cryptographic protocols.

In the world, hepatocellular carcinoma (HCC) is one of the most common and most lethal cancers. Currently, standard therapy for unresectable HCC is a local-regional therapy with transarterial chemoembolisation (TACE). In this study, we sought to assess whether plasma circulating microRNAs (miRNAs) can be used to predict the prognosis of HCC patients receiving the TACE treatment. Firstly, we systematically examined TACE therapeutic effectiveness-related circulating miRNAs through miRNA Profiling Chips. As a result, we identified 19 circulating miRNAs to be significantly differentially expressed between the TACE-response group and the TACE-nonresponse group. In the second stage, we performed quantitative analyses of these candidate miRNAs in additional HCC patients treated with TACE and validated two of the aforementioned 19 miRNAs (miR-1285-3p and miR-4741) as candidate biomarkers for predicting prognosis of TACE. Interestingly, we found that miR-1285-3p could directly repress JUN oncogene expression in HCC cells, indicating miR-1285-3p could act as a potential tumor suppressor. In conclusion, our data indicate that circulating miR-1285-3p and miR-4741 was predictive of response to TACE therapy in HCC.