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Construction of a colorimetric nanosensor for detecting As(III) in water

LI Jian, RUAN Yue, YANG Liang, LIU Bianhua

2020, 50(7): 873-879. doi: 10.3969/j.issn.0253-2778.2020.07.001

Abstract:
For the shortcomings of traditional large-scale instruments in the aspect of real time in SITU detection and operability for detecting pollutant in water. A portable colorimetric nanosensor was constructed for the real time and in situ detection of As(III) in water. The nanosensor consisted of gold nanoparticles modified with trithiocyanuric acid (TMT-AuNPs), and its detection limit for As(III) reached 0.87 μg/L. It is believed that the colorimetric nanosensor will have wide application prospects in outdoor visual detection scenarios.

Development of an in situ high-pressure catalytic reactor for synchrotron radiation photoionization mass spectrometry

YU Shengsheng, WEN Wu, XU Minggao, YANG Jiuchong, BI Hailin, WANG Xudi, QI Fei, PAN Yang

2020, 50(7): 880-886. doi: 10.3969/j.issn.0253-2778.2020.07.002

Article Views:118 Full article PDF

Abstract:
An in situ high-pressure catalytic reactor which can be coupled with synchrotron radiation vacuum ultraviolet photoionization mass spectrometry was developed. A tapered micro orifice was designed at the top of the high-pressure reaction tube for the first sampling, along with a quartz nozzle downstream connected with the mass spectrometry for the second sampling. Thus, the working pressure range of the reactor could reach from atmosphere to 3.6 MPa. In this design, gas dynamics theory and COMSOL Multiphysics software were applied for simulation, and the simulation results were verified by experimental measurements. The dimethyl ether (DME) carbonylation to methyl acetate reaction under different pressures near working conditions was studied by in situ mass spectrometry simultaneously. It was found that the selectivity of methyl acetate obtained in real time increased significantly with the increase of reaction pressure. The development of the in situ high-pressure catalytic reactor will be helpful to further study gas-solid catalytic reaction mechanism under high pressure.

Protective effect of Fe3O4 nanoparticles on cadmium chloride-induced toxicity in the small intestine of mice

WANG Xiaoqin, ZHANG Yan, TAN Weihang, NIE Kai, XU Xiaolong

2020, 50(7): 887-893. doi: 10.3969/j.issn.0253-2778.2020.07.003

Article Views:94 Full article PDF

Abstract:
Synergistic toxicity from multiple environmental pollutants poses greater threat to humans. Here we evaluated combined toxicity of environment pollutants Fe3O4 nanoparticles (nano-Fe3O4) and cadmium chloride (CdCl2) in the small intestine of mice. The results showed that Fe3O4 nanoparticles (nano-Fe3O4) and CdCl2 have a negative synergistic toxicity in the small intestine of mice. Oral nano-Fe3O4 did not show obvious toxicity in the small intestine of mice. In contrast, oral CdCl2 caused significant oxidative stress in the small intestine of mice. CdCl2-induced oxidative stress resulted in inflammatory response in the small intestine as indicated by the significant increases in the levels of cyclooxygenase-2 and nitric oxide synthase as well as the inflammatory cell infiltration in the small intestinal tissue. Co-exposure to nano-Fe3O4 and CdCl2 significantly attenuated the CdCl2-induced damage in the small intestine through reduction of oxidative stress and inflammatory response.

Green synthesis of silver nanoparticles and their photocatalytic degradation performance of tetrabromobisphenol A

LI Wenjie, YU Shengsong, CHEN Jiejie

2020, 50(7): 894-900. doi: 10.3969/j.issn.0253-2778.2020.07.004

Article Views:104 Full article PDF

Abstract:
Silver nanoparticles (AgNPs) could enhance the photocatalytic reaction significantly owing to its surface plasmon resonance (SPR) effect. However, AgNPs are usually unstable without the ligands and their preparation process always requires organic chemicals as the reducing agents. In this work, humic acids (HA), widely existent in environmental water samples, were used as both reductant and ligand for in situ synthesizing and stabilizing AgNPs under simulated sunlight. The results of photocatalytic experiments indicate that the as-prepared AgNPs show excellent activity for the degradation of tetrabromobisphenol A (TBBPA), a typical organic halogenated pollutant in water. With AgNPs generated in the mixture of 1 mg/L HA and 2 mmol/L Ag+, 74.9% TBBPA was degraded in 1 h. This degradation efficiency is much better than that of commercial AgNPs. Through controlling the reaction conditions, neutral pH was found to be beneficial for the degradation of TBBPA, which would lower the requirements of equipments and reaction conditions in practical applications. By the inhabitation test of active species, singlet oxygen (O2), hydroxyl radical (·OH) and superoxide anion (O2·-) generated via the SPR effect of the in situ formed AgNPs under illumination, were simultaneously identified to be the active species in the degradation of TBBPA. Therefore, the AgNPs with high photocatalytic activity are in situ synthesized by using cheap HA under mild conditions, exhibiting potential for applications in photocatalytic degradation of organic pollutants in wastewater.

Using splines on triangular mesh to solve PDE with nonhomogeneous boundary

WANG Zhihua, KANG Hongmei

2020, 50(7): 901-905. doi: 10.3969/j.issn.0253-2778.2020.07.005

Article Views:82 Full article PDF

Abstract:
The spline spaces S,02(Δ(2)mn) defined on type Ⅱ regular triangulation are directly used to solve the PDE problems with homogeneous boundary.For the PDE problems with nonhomogeneous boundary, the solutions obtained usually do not satisfy the convergence properties if they are still solved in the spline spaces S,02(Δ(2)mn),because the basis functions of S,02(Δ(2)mn) vanish on the boundary of the parameter domain. Here, based on the spline spaces S,02(Δ(2)mn) and S2(Δ(2)mn) defined on type Ⅱ regular triangulation,a set of blended spline basis functions were formed by combining the basis functions of S,02(Δ(2)mn) with the basis functions of S2(Δ(2)mn) whose support centers are all outside the boundary of the parameter domain.The blended spline functions were used to solve the PDE problem with nonhomogeneous boundary.Experiment results show that the solutions obtained by this method are convergent.

Raman study of surface modified bi-layer graphene under high pressure

DU Jinxiang, NI Kun, TAO Zhuchen, ZHU Yanwu

2020, 50(7): 906-911. doi: 10.3969/j.issn.0253-2778.2020.07.006

Article Views:78 Full article PDF

Abstract:
Raman spectroscopy is one of the most effective ways to characterize the structure and properties of graphene. The interlayer interactions in bi-layer graphene

Factors influencing the amount of atmospheric black carbon over the southern ocean and the Tropical Western Pacific Ocean

SU Chenyun, YUE Fange, Kang Hui, Yu Xiawei

2020, 50(7): 912-919. doi: 10.3969/j.issn.0253-2778.2020.07.007

Article Views:101 Full article PDF

Abstract:
Black carbon (BC) has direct and indirect climatic effects and can be transported over long distances. Knowledge of the concentration and distribution of BC aerosol in the globe is of significant climatic importance. During the 34th Chinese Antarctic Research Expedition (CHINARE), the concentrations of BC were measured by multi-angle absorption photometer (MAAP). The factors influencing the level of BC were investigated based upon NOx and other data measured synchronously. Excluding the influence of ship emissions, the BC concentrations of the ocean areas from Zhongshan station to France station, and the Ross Sea in the Southern Ocean, and the tropical Western Pacific Ocean was 7.86 ng/m3±15.52 ng / m3, 4.73 ng/m3±11.52 ng/m3, and 17.80 ng/m3±32.71 ng / m3, respectively. Further source analysis showed that BC concentrations over the Ross Sea reflect the natural background of the Antarctic continent, the relatively high BC concentrations over the tropical Western Pacific Ocean may be related to the terrestrial sources, and the estimated dry deposition flux of BC aerosol is much higher than the model results.

Influence analysis of tuning parameters on the change-point estimation in CUSUM type statistics

TAN Changchun, JIANG Min

2020, 50(7): 920-928. doi: 10.3969/j.issn.0253-2778.2020.07.008

Article Views:122 Full article PDF

Abstract:
Generally, the range of tuning parameters in CUSUM type change-point estimation statistic is assumed to be (0,1) in theory. But the different values of tuning parameters often lead to the different estimation results in application. Here Monte Carlo method was used to study the influence of tuning parameters on the change-point estimation based on the jump change-point model. It was found that when the jump is large, the change-point estimate is not affected by the value of tuning parameters no matter where the true location of the change-point is. However, the value of tuning parameter has a significant effect on the change-point estimate when the jump is small. Especially, when the true location of change-point is close to one of the two trails, best estimation is obtained with the tuning parameter at 0.5. When the true location of change-point is near the center of sequence, it was observed that the smaller the tuning parameter, the better the estimation. On the basis of simulation and applications, a data-driven method was proposed to select appropriate tuning parameters from a set of possible values, which makes the CUSUM type change-point estimator more robust.

Markov chains prediction model of insurance lapse or surrender probability

ZHANG Ying

2020, 50(7): 927-933. doi: 10.3969/j.issn.0253-2778.2020.07.009

Article Views:238 Full article PDF

Abstract:
The continuous-time time-homogeneous Markov chain was used to construct a prediction model about the probability of insurance lapse or surrender to calculate the probability of being in various states at any time, and a parameter estimation method was given. In reality, the state of the insurance policy would have discrete events at a specific time, so the multi-stage Markov chain model was used to characterize this feature. That was, at a specific time when a discrete event occurs, a jump matrix was defined to describe the state transition at the specific time. The model was applied to the study of the life insurance lapse or surrender probability of insurance companies, and the model parameters were estimated and calibrated by actual data. Finally, the calibrated Markov chain model was used to predict the life insurance lapse or surrender probability and a good prediction result was obtained.

The risk factors and perinatal outcomes of umbilical vessels thrombosis

ZHU Ying, LIU Yanyan

2020, 50(7): 936-939. doi: 10.3969/j.issn.0253-2778.2020.07.010

Article Views:67 Full article PDF

Abstract:
Objective: The aim of this study is to examine the association between the various risk factors associated with umbilical cord thrombosis, and to evaluate perinatal outcomes. Methods: A retrospective study of umbilical cord thrombi enrolled between 2015~2018 was carried out. Data were analyzed from the medical archives of Tongji Hospital, Huazhong University of Science and Technology. The diagnoses of all cases were confirmed by histopathology. Results:5 of 8 cases were umbilical vein embolism and 3 were umbilical vein thrombi. Gross examination reported 6 cases of additional cord abnormalities, including 2 cases of anomalous of umbilical cord lengths, 2 cases of hyper-coiling, 1 case of swollen cord with deficiency of Wharton’s jelly, and 1 case of placenta velamentous. There are 4 cases termed gestational diabetes disorders, including 3 were gestational diabetes mellitus and one had a history of type I diabetes. Clinical findings depicted that the chief complaint of 4 patients was decreased fetal movement, 3 patients were unsatisfied with electronic fetal monitoring (EFM) and 1 was routine delivery. Perinatal outcomes: With the exception of 2 stillbirths, the remaining 6 cases were terminated by cesarean section. Six infants are alive, including one was SGA（small for gestational age）,one was LBW（low birth weight）and one was VLBW that all infants transferred to neonatology department. Conclusion: We have observed that umbilical structural dysplasia and abnormal blood glucose may lead to the formation of thrombosis. Focus on important signs from prenatal ultrasound, EFM tests and fetal movements can help in improving the screening rate of umbilical cord thrombi. Our results support in the more effective approach of performing emergency cesarean section as soon as possible completed with antenatal corticosteroid therapy for fetal lung maturation in the third trimester.

DEA based production planning considering attainability and management goals with undesirable outputs

ZENG Wenjiang, YANG Feng

2020, 50(7): 940-949. doi: 10.3969/j.issn.0253-2778.2020.07.011

Article Views:59 Full article PDF

Abstract:
The problem of production planning in a centralized decision-making environment usually involves the participation of all subunits, and each subunit makes its own contribution to the total production. When making a production planning, the central decision-maker needs to determine the inputs and outputs quantities of each subunit based on the changes in product demand and available resources that are known or predictable in the next quarter. On the one hand, due to the relative stability of the production technology level in the short term, it is unrealistic to greatly increase production, we need to consider the attainability of the production planning, that is, the closer the production plan for the next quarter is to the production status of the current quarter, the easier it is to achieve. On the other hand, in the previous production planning research, the central decision-maker did not formulate targeted management goals for each subunit, so that the production plan cannot fully reflect the manager’s expectations of the goal, so the management goals should be taken into account, and the production planning is required to be as close as possible to the management goals. In addition, in the production process, outputs can be divided into desirable and undesirable outputs.From these perspectives, a production planning method based on data envelopment analysis(DEA) for decision-making units with undesirable outputs was proposed by considering the attainability of production planning and management goals set in advance in a centralized decision-making environment. The proposed model was illustrated by the real cases of 32 paper mills along the Huaihe River in Anhui Province, China.

Research on optimization method of convolutional neural network based on visualization

WANG Yue, LI Jing

2020, 50(7): 959-967. doi: 10.3969/j.issn.0253-2778.2020.07.013

Article Views:72 Full article PDF

Abstract:
With the lifting force computer calculation, the application range of the depth of learning more and more widely. However, the design and tuning of deep learning models is very difficult. For complex models, adjusting only one layer of the network may lead to very different results. Many researchers usually adjust their parameters based on past experience, make a lot of trial and error, and wasting a lot of time and energy. Based on the data characteristics of the convolutional neural network model, this paper proposes a method of auxiliary parameter adjustment based on visualization. Analyze the internal data of the convolutional neural network by visualization and analyze the information represented by it, so as to quickly locate the model fault, realize targeted parameter adjustment, reduce the difficulty of researchers in parameter adjustment, and improve work efficiency.

Focused loss-based for imbalanced data scenarios integrated classification methods for CGAN

CUI Wenquan, YU Houying, HOU Xiaotian

2020, 50(7): 968-976. doi: 10.3969/j.issn.0253-2778.2020.07.014

Article Views:69 Full article PDF

Abstract:
For the case of imbalanced data, an integrated classification method for CGAN-focal-loss was investigated based on conditional generative adversarial networks (CGAN) using gradient boosting trees. The method first reduces the imbalance rate by CGAN, and further improves the classification performance of the classifier by increasing the focus on a few classes of samples through the weight balancing of the focused loss combined with the GBDT algorithm. The properties of the method were investigated and several theoretical results were obtained. It was proved that the empirical conditional distribution generated by CGAN converges to the conditional distribution of the corresponding aggregate under certain conditions; that the empirical risk of the CGAN method with focused loss converges to the expected risk; and that the estimator of the method converges to the function that minimizes the expected risk. The experimental results show the good performance of the CGAN-focal-loss method.

The effect of police trust repair strategies: Empirical test under the situation of sudden police corruption

LI Hui, LI Yixuan, WANG Na

2020, 50(7): 977-984. doi: 10.3969/j.issn.0253-2778.2020.07.015

Article Views:79 Full article PDF

Abstract:
Under the situation of sudden police corruption, effect difference of different trust repair strategies was systematically analyzed through three experiments. The experimental results showed that: Firstly, the effects of trust repair strategies under different trust violation type have significant differences. When faced with power-oriented trust violation, the effect of combined strategy of “apology and commitment” is the best, and it needs be cautious and prudent to use the denial repair strategy; and in responsibility-oriented violation, the combined strategy of “denial and commitment” can better soothe people’s negative emotions, and repair damaged trust. Secondly, repair time has great influence on trust repair effect. Trust repair strategies after a brief delay have good effect, but the best delay time should not be dragged too long, and long time delay, such as 1 week, is ineffective even may lead to the reverse effect (bad results). Thirdly, intervention of third party has significant influence on trust repair effect. The higher the government credibility is, the better of trust repair strategies’ effect is，and it is helpful to repair the fragility of police trust.

Cooperation mode selection and pricing between hotel and OTA considering consumer preference under dual-channel supply chain

WANG Xin, ZHU Yangguang, WU Zun

2020, 50(7): 985-992. doi: 10.3969/j.issn.0253-2778.2020.07.016

Article Views:77 Full article PDF

Abstract:
In the context of the tourism supply chain, based on the different cooperation mode in the dual channel marketing strategy between the hotel and the online travel agency (OTA): commission mode and merchant mode, the choice of cooperation mode and pricing between hotel and OTA was studied. There is a Stackelberg game between the hotel and the OTA. The hotel as a tourism provider occupies a dominant position in the game, OTA as a follower is required to decide sales effort.

Fuzzy local coordinate concept factorization with graph regularization

ZHANG Yikai, PENG Yong, KONG Wanzeng, WEN Yimin

2020, 50(7): 993-1002. doi: 10.3969/j.issn.0253-2778.2020.07.017

Article Views:59 Full article PDF

Abstract:
Matrix Factorization is an effective and efficient method to solve clustering problems in machine learning. However, for most traditional which factorization based models in clustering, there are two necessary steps to get the final assignments. First, original data can be decomposed to a basis matrix and a coefficient matrix through a certain model. Second, the learned coefficient matrix is fed into K-means to make discretization. This two-step paradigm causes extra computational burden and may have some side effect on the final results due to the sensitivity to initialization of K-means. To this end, a novel model termed fuzzy local coordinate concept factorization with graph regularizer (FLCCF-G) is proposed. Which avoids using K-means by enforcing the sum of each row of the non-negative coefficient matrix to equal to one. Then the final clustering results can obtained directly by checking the maximum value of each row of the coefficient matrix. In addition, through this constraint, our proposed model changes is a fuzzy clustering model rather than hard clustering, indicating that the model has better interpretability to data points in boundaries of different clusters. Extensive experimental results on synthetic and Benchmark data sets indicate the better performance of FLCCF-G on data clustering.

The uncertainty of projection of precipitation change in the middle and lower reaches of the Yangtze River under the RCP8.5 scenario

KONG Haimei, LI Gen, SUN Liang

2020, 50(7): 1003-1012. doi: 10.3969/j.issn.0253-2778.2020.07.018

Article Views:49 Full article PDF

Abstract:
Summer precipitation changes in the middle and lower reaches of the Yangtze River under global were estimated, using the historical simulation of the fifth coupled mode comparison plan (CMIP5) and the experimental data under the high concentration scenario of the typical concentration path (RCP8.5). The results show that the multi-mode average predicted global warming has a small increase in precipitation variation in the middle and lower reaches of the Yangtze River. On the one hand, global warming leads to an increase in water vapor content, which is conducive to the increase of precipitation in the Yangtze River Basin. On the other hand, global warming has caused the Summer monsoon circulation to weaken, and the weakened summer monsoon is not conducive to the increase of precipitation in the Yangtze River basin. Under the combined effect of the two, the multi-model average estimated mid-downstream watershed in the Yangtze River has no obvious changes in summer precipitation. However, there is a large inter-mode uncertainty in this estimate. The analysis shows that the uncertainty of the prediction of precipitation change is mainly due to the uncertainty of precipitation prediction results caused by large-scale Summer monsoon circulation changes, and the increase of water vapor caused by climate warming has less influence on the uncertainty of precipitation variation. Further research on this source of uncertainty shows that precipitation in the middle and lower reaches of the Yangtze River and changes in the East Asian summer monsoon circulation are strongly correlated with the warming of the North Atlantic and the the Western North Pacific SST. This indicates that in the context of global warming, the warming of the North Atlantic and the Western North Pacific SST has a great impact on the prediction of precipitation changes in the middle and lower reaches of the Yangtze River. If the uncertainty of the prediction of the North Atlantic and the Western North Pacific SST is reduced, the precipitation prediction results in the middle and lower reaches of the Yangtze River will be more reliable.

Identification of PBMC-related cells of single cell RNA sequence data

GONG Lejun, ZHOU Shehai, CHENG Yifei, GAO Zhihong, LI Huakang

2020, 50(7): 1013-1018. doi: 10.3969/j.issn.0253-2778.2020.07.019

Article Views:133 Full article PDF

Abstract:
Cell type identification is one of the main tasks of single cell RNA sequencing. This paper proposes an automatic identification of cell types based on random forest (AICTRF) method to identify cell types in single-cell sequencing data. This method uses the random forest classification model for training, and then predicts unknown cell types according to the trained model. A random forest classification model was trained on human peripheral blood mononuclear cells (PBMC) sequencing data set to predict the cell types of related subtypes of human PBMC B cells. The results show that the proposed method can help researchers automatically identify cell types in single-cell sequencing data.

A malicious domain name detection method based on CNN

DU Shuying, DU Peng, DING Shifei

2020, 50(7): 1019-1025. doi: 10.3969/j.issn.0253-2778.2020.07.020

Article Views:96 Full article PDF

Abstract:
In recent years, various cyber attacks based on botnets have been one of the cyber security threats. Various malwares use the Domain Generation Algorithm (DGA) to automatically generate a large number of pseudo-random domain names to connect to commands and control servers. The detection and classification of pseudo-random domain names based on the convolutional neural network (CNN) method is focused on. A brief introduction is given to the hazards, basic principles of botnets, and the role of fake domain names in botnets. After analyzing the principle of DGA algorithm and the defects of traditional DGA domain name recognition algorithm,emphasis is laid on the research of fake domain name recognition method based on convolutional neural network. The basic concept of convolutional neural network is expounded by simple neural network training experiments. The differences of the model's effect on solving classification problems under different hyperparameters and different excitation functions are simulated. In the analysis of the model operation results, the accuracy and loss function of the domain name identification by the convolutional neural network model are given, and the evaluation indexes of the accuracy, recall, F1 and ROC curves are printed out. All indicators show that the classification of the model is good. It is concluded that counterfeit domain name recognition based on CNN is a reliable method.

Adaptive fractional order particle swarm optimization using swarm activity feedback and mutation operator

SU Shoubao, CHEN Qiuxin, WANG Chishe, LI Zhi

2020, 50(7): 1026-1034. doi: 10.3969/j.issn.0253-2778.2020.07.021

Article Views:100 Full article PDF

Abstract:
The basic particle swarm optimizer with fractional-order (FOPSO) is easy to fall into premature convergence, because its overall performance depends on the fractional order α. To solve the problem, a new adaptive fractional-order PSO algorithm, SFOPSO is proposed, by cooperating mutation operators into swarm activity feedback with S-model. During the iteration of this new algorithm, the fractional-order α of particles is adjusted adaptively according to the swarm activity with S-model and the activity value of single particles. At the same time, to enhance the ability of the swarm to escape out of local optimum during the process of exploitation or exploration, the hybrid model was designed by using mutation operators. The convergence of the proposed algorithm SFOPSO is analyzed theoretically and the experimental results show that the proposed algorithm is practicable and effective in improving convergence accuracy and convergence speed.

2020 Vol. 50, No. 7

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