Experimental study on the composite fouling characteristics of calcium carbonate and nanometer magnesia

Zhiming Xu,Jingtao Wang,Zhimin Han,Yu Zhao 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.1

In order to study the composite fouling characteristics of crystallization and particulate, the fouling characteristics of calcium carbonate (CaCO 3 ) and nanometer magnesia in the alternating elliptical axis tube were investigated experimentally. The results show that CaCO 3has obvious effect on the inhibition of the formation of particulate fouling. The asymptotic value of fouling resistance of the nanometer magnesia is the highest and the CaCO 3 is the lowest, and the composite fouling is between them. The fouling rate and the asymptotic value of composite fouling resistance decrease with the increase of the CaCO 3 concentration. The time reaches to the asymptotic value of the three experiments are similar. The variation of nanometer magnesia concentration has greater influence than the CaCO 3 concentration on the asymptotic value of composite fouling. The fouling rate and the asymptotic value of composite fouling resistance increase obviously with the increase of the nanometer magnesia concentration.

The Deviation Characteristics of High-speed Train Running Time in Section and its Effect on Transport Capacity

Zhiming Yuan,Qi Zhang,Tao Wang,Feng Chen 보안공학연구지원센터 2016 International Journal of Hybrid Information Techno Vol.9 No.10

Starting from the phenomenon that a large number of trains’ actual arrival & departure time deviate from specified time in train working diagram in the database of high speed railway dispatching system, the paper analyzes the defects of current train running time calculation method. Based on data mining theory, a section running time deviation calculation model for high speed railway train is proposed. Then the properties of train section running time deviation are studied in three different cases (non-stop both at the start and the end of section, stop at the end of section, and departure at the start of section) with the data from a Chinese railway bureau dispatching system, and its further influence on carrying capacity is analyzed. The results show that three deviation cases all fit Gauss distribution and the accumulative deviation time can increase the transport capacity for more than 1 million passengers per year.

Modeling of SACK-based Fast Retransmission and Recovery

Zhiming Wang,Xiaoping Zeng,Xiaofan Jia,Xue Liu,Li Chen 보안공학연구지원센터 2016 International Journal of Future Generation Communi Vol.9 No.6

Selective acknowledgment (SACK)-based retransmission and recovery mechanism has been implemented in most of current transmission control protocol (TCP) stacks. A new SACK-based loss recovery algorithm is defined in RFC6675 under standard track. Existing models in literatures on modeling TCP SACK, which usually use SACK-based retransmission and recovery mechanism, is no longer accurate for two reasons: 1) they ignore transmission of new packets before retransmission of the last loss; 2) they are based on the strategy that pipe is decreased by 2 upon receipt of a partial ACK, where pipe is the estimated number of outstanding packets. This paper develops a new method to derive the expected number of new packets transmitted between retransmission of the first loss and the last, proposes a model that estimates the expected number of packets transmitted during fast retransmission and recovery phase (FRR) and the corresponding expected duration based on RFC6675. The numerical results show that the proposed model can accurately estimate the expected number of packets transmitted during FRR and the corresponding expected duration based on RFC6675.

Linguistic Angst and Multiculturalism: The Singaporean Experience

( Zhiming Bao ) 부경대학교 글로벌지역학연구소 2017 Journal of Global and Area Studies(JGA) Vol.1 No.1

Singapore is a multiethnic, multilingual city-state since its founding. Within the multilingual society, the languages have well-defined functions: English is the working language, and Chinese (Mandarin), Malay and Tamil are the mother tongues of the respective ethnic groups. Within the Chinese community, the traditional dialects are Southern Min (Hokkien, Teochew) and Cantonese. After independence, the government chose English as the working language, closed vernacular schools, and promoted Mandarin within the Chinese community. Within a short span of 40 years since independence, the young Singaporeans have virtually abandoned dialects in favor of English and Mandarin. The government`s language policy has created a multilingual, multicultural community. This article traces the history of the language situation in Singapore, and describes the linguistic angst that permeates the community. The linguistic angst is manifested in language choice, language identity, and language confidence, among others. Linguistic angst is perhaps the by-product of multilingualism and multiculturalism.

Shear Behavior of Marlstone Containing Parallel Fissure under Normal Unloading

Zhiming Yin,Xinrong Liu,Zhongping Yang,Yanlei Wang 대한토목학회 2021 KSCE Journal of Civil Engineering Vol.25 No.4

Shear tests under normal unloading were carried out to further study the shear mechanical behavior of marlstone containing parallel fissures. The results reveal that the failure on the rock bridge is tensile failure except for the limited extrusion failure at the tip of the prefabricated fissure. The failure on both sides is generally tensile-shear mixed failure, in which the tensile failure is mainly concentrated in the middle of both sides. In general, it can be summarized as a tensile-shear failure mode of STS-T-STS (S means shear failure, T means tension failure). The failure normal stress of the specimens gradually increases and then decreases with the increase of the fissure inclination, increases with an increase in the initial normal/shear stress, and decreases with the increase of the unloading rate. Strong dilation occurred in the shear process of the specimens, which shows obvious arch effect. The variation law of dilatancy deformation and horizontal deformation in the stage of normal stress unloading is just opposite to that of the failure normal stress. The increasing effect of high shear stress on shear deformation is greater than that of dilatancy deformation, while the inhibiting effect of high normal stress on dilatancy deformation is greater than that of the shear deformation.

Characteristics of calcium carbonate fouling on heat transfer surfaces under the action of electric fields

Zhiming Xu,Hongliang Chang,Bingbing Wang,Jingtao Wang,Qi Zhao 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.7

The present study examined the effect of electric fields in calcium carbonate (CaCO 3 ) scale formation on a heat transfer surface. The effects of electric fields ranging from 0 V to 4000 V on the fouling properties of CaCO 3 were investigated. Results showed that the optimal electric voltage was approximately 500 V, at which the asymptotic value of fouling resistance and the deposited weight were minimal and corresponded to 52.8 % and 61.3 % reductions, respectively, compared with the results recorded at 0 V. At higher voltages of 3000 V or 4000 V, the asymptotic value of fouling resistance and the weight of fouling deposits increased relative to those obtained at 0 V. The scanning electron microscope images of the fouling deposits obtained at 0 V showed mainly aragonites with sharp and needle-like crystal structures. The structure of CaCO 3 fouling changed from aragonites to spherical vaterites as the applied voltage was increased.

ZnO nanowire array ultraviolet photodetectors with self-powered properties

Zhiming Bai,Xiaoqin Yan,Xiang Chen,Hanshuo Liu,Yanwei Shen,Yue Zhang 한국물리학회 2013 Current Applied Physics Vol.13 No.1

A ZnO nanowire (NW) array ultraviolet photodetector (PD) with Pt Schottky contacts has been fabricated on a glass substrate. Under UV light illumination, this PD showed a high photo-to-dark current ratio of 892 at 30 V bias. Interestingly, it was also found that this PD had a high sensitivity of 475 without external bias. This phenomenon could be explained by the asymmetric Schottky barrier height (SBH) at the two ends causing different separation efficiency of photogenerated electronehole pairs, which resulted in the formation of photocurrent. It is anticipated to have potential applications in self-powered UV detection field.

Maximum magnetic entropy change modulated toward room temperature in perovskite manganites La0.7−xNdx(Ca,Sr)0.3MnO3

Zhiming Wang,Qingyu Xu,Kaixin Chen 한국물리학회 2012 Current Applied Physics Vol.12 No.4

With Nd3þ doping and Ca2+, Sr2+ modulating in the solegel technique, a series of polycrystalline perovskite samples La0.7-xNdx(Ca,Sr)0.3MnO3 (x = 0, 0.05, 0.1, 0.15, 0.20, 0.25) was prepared, their maximum magnetic entropy changes were tuned to room temperature (ΔSH=-1.47 J/kg K at 298 K for La0.45Nd0.25(Ca,Sr)0.3MnO3), an enhancement of the maximum magnetic entropy change (ΔSH=-1.89 J/kg K at 315 K) and its refrigerant capacity (about 45.3 J/kg) had also been obtained under 9 kOe magnetic field variation for La0.55Nd0.15(Ca,Sr)0.3MnO3 contrast to La0.7(Ca,Sr)0.3MnO3.

Video Quality Assessment based on Deep Neural Network

( Zhiming Shi ) 한국인터넷정보학회 2023 KSII Transactions on Internet and Information Syst Vol.17 No.8

This paper proposes two video quality assessment methods based on deep neural network. (i)The first method uses the IQF-CNN (convolution neural network based on image quality features) to build image quality assessment method. The LIVE image database is used to test this method, the experiment show that it is effective. Therefore, this method is extended to the video quality assessment. At first every image frame of video is predicted, next the relationship between different image frames are analyzed by the hysteresis function and different window function to improve the accuracy of video quality assessment. (ii)The second method proposes a video quality assessment method based on convolution neural network (CNN) and gated circular unit network (GRU). First, the spatial features of video frames are extracted using CNN network, next the temporal features of the video frame using GRU network. Finally the extracted temporal and spatial features are analyzed by full connection layer of CNN network to obtain the video quality assessment score. All the above proposed methods are verified on the video databases, and compared with other methods.

The SnRK2 family in pepper (Capsicum annuum L.): genome-wide identifcation and expression analyses during fruit development and under abiotic stress

Zhiming Wu,Jiaowen Cheng,Fang Hu,Cheng Qin,Xiaowan Xu,Kailin Hu 한국유전학회 2020 Genes & Genomics Vol.42 No.10

Plant-specifc SnRK2 (sucrose nonfermenting-1-related protein kinase 2) genes play crucial roles in the coordination of plant growth and development and responses to stress. However, comprehensive studies have not been performed for this gene family in pepper (Capsicum annuum), a very important Solanaceous vegetable worldwide. To fully understand the status of SnRK2s in chili pepper, a total of 9 putative SnRK2 genes (named CaSnRK2.1-2.9) were identifed in pepper in the present study. These genes were located on 7 diferent chromosomes and classifed into three subfamilies based on the phylogenetic tree. Their conserved motif compositions and exon-intron structures were systematically analyzed, and the results strongly supported the classifcation. Furthermore, a total of 81 putative cis-elements were found in the promoter regions, and the cis-elements related to hormone and stress signaling were abundant. Finally, the CaSnRK2 gene expression profles among diferent tissues, especially developing fruit tissue, and under various abiotic stresses were investigated to identify tissuespecifc or stress-responsive candidates. This study was the frst to comprehensively investigate the SnRK2 family in pepper, and the results provide important clues for further functional analyses of fruit development and abiotic stress responses.