Refining Characteristics of Hardwood Pulp Using Straight- and Curved-bar Plates: A Time Series Study

Huan Liu,Jixian Dong,Xiaojun Jiang,Chong Luo,Xiaohui Tian,Ruifang Yang,Litao Zhang,Bo Wang,Yan Yan 한국펄프·종이공학회 2019 펄프.종이기술 Vol.51 No.5

There are obvious differences in the refining characteristics of plates with straight bars compared to curved bar plates having the same bar parameters during refining. The objective of this research is to explore the difference in the refining characteristics of the straight bar and curved bar plates on experimental and theoretical studies. The bar angle of the curved bar plate is defined, and the two plates are used in the refining of bleached sulphate eucalyptus pulp (BSEP). Samples at different refining times were collected, and the properties of the fibers, pulp, and paper were detected and analyzed. It was found that the curved bar and straight bar plates have a similar influence on the pulp SR freeness. However, the curved bar plate effectively retained the fiber length, which means that its fiber cutting effect is weaker than that of the straight bar plate. Meanwhile, the fiber external fibrillation of the samples refined by the curved bar plate was better than that of the samples refined by the straight bar, which showed a higher tensile and tear index of the formed paper. Through the theoretical analysis of refining intensity via characterization of the parameter bar edge length (BEL), the specific edge load (SEL) of the curved bar plate was lower, and the refining characteristics predicted by the refining intensity were similar to the results from the experiments conducted in this paper.

Preparation and Characterization of Transitional Alumina Obtained through Ammonia Treatment

Yan Liu,Litao Jia,Bo Hou,Debao Li 대한화학회 2015 Bulletin of the Korean Chemical Society Vol.36 No.12

In this study, different aluminas were obtained by precipitating Al(NO3)3·9H2O with different concentration of aqueous solution of ammonium carbonate. The obtained aluminas were treated by 50 (vol/vol) % ammonia via low temperature immersing and high temperature hydrothermal treatment, respectively, then, the treated aluminas were calcined again. The crystal types, morphology, textural properties, and pore distribution of the original alumina, ammonia-treated alumina, and the second calcined alumina were studied by characterizations of X-ray diffraction, thermogravimetric analyses, nuclear magnetic resonance, Brunauer-Emmett-Teller (BET), transmission electron microscopy, and so on. Several modified aluminas with specific morphology, desired pore structure, and pure crystal types were obtained, which can be used in some specific industrial application.

Study of Visual Spatial Perception Performance at Close Range in Underground Coal Mine

Ren Dawei,Liu Yang,Chen Litao 보안공학연구지원센터 2015 International Journal of Signal Processing, Image Vol.8 No.11

In coal mines the environment is complex, crowded with personnel and equipment, as well as lack of colors. The safety in production is influenced by visual spatial perception is whether or not accurate. The visual spatial perception precision plays a significant even crucial role in positioning. By simulating the environment in coal mines, the positioning experiment about participants’ visual spatial perception performance of different target objects in two models—from far to near and from near to far has been carried out. Experimental results showed that visual spatial perception distance was significantly shorter than target range, that visual spatial perception in deep pink was the poorest. In addition, the H has become appreciable and regular with visual spatial perception changing. The experimental results provided references for setting warning marks, safe distances and choosing colors for infrastructure in coal mines.

Study on the influence of hold-down spring on the vibration characteristics of core barrel

Tan Tiancai,Sun Lei,Liu Litao,Yang Jie 한국원자력학회 2023 Nuclear Engineering and Technology Vol.55 No.9

The influence of hold-down spring (HDS) on the vibration characteristics of core barrel is studied in this paper. First, the vibration characteristics experiment of core barrel was carried out with four type of different hold-down spring. These hold-down springs represent the same hold-down force under different spring stiffness and different hold-down force under the same spring stiffness. And then a new finite element method for researching the influence of hold-down spring on the vibration characteristics of core barrel was presented. This new method could consider the influence of the hold-down force and the spring stiffness at the same time. The results suggest that, the hold-down force and friction have greater influence on the vibration characteristics of core barrel than the spring stiffness, and the influence is nonlinear. The influence of the boundary condition on beam mode is greater than that on shell mode for core barrel.

Perspectives on China-Africa Relationships in a context of

Changing World,Zhenke Zhang,Litao Liu 한양대학교 유럽-아프리카연구소 2022 글로벌 거버넌스와 문화 Vol.2 No.1

When talking about Sino-African relationships recently, few concern about China- Africa relationships in the context of the changing world. This study generally reviewed the background of the changing world and the evolution of China-Africa relations. For a long time, the Africa has been regarded as the hopeless continent. In the new century, the African countries experienced a transition from hopeless continent to rising Africa with more potentials. The state and private Chinese enterprises went to African countries not only for the crude oil and gas, the mining, and the forestry business, but also as important partner in infrastructure construction, joint enterprises as well as international trade partners. Most western views of China in Africa contained with negative attitude in the globalization era. The globalization and changing world gave the opportunity for China to improve the relations with African countries, especially in the economic relations. From 2009 to present, China became the top international trade partner in the whole Africa. There are also arguments with China in Africa in the future. The world is a complex socio-ecological system and corresponding with rapid changes, we provide the perspectives on the China-Africa relations in the context of changing world.

The upregulation of keratocan promotes the progression of human pancreatic cancer

Gao Huijie,Qian Ruikun,Ren Qiang,Zhang Litao,Qin Wei,Zhou Caiju,Wang Huiyun,Liu Chao,Zhang Yuntao 대한독성 유전단백체 학회 2024 Molecular & cellular toxicology Vol.20 No.2

Background The role of the extracellular matrix (ECM) in oncogenic contexts has been studied previously, but the expression patterns and functional role of keratocan, a classical small leucine-rich proteoglycan found in the ECM, in tumors remain poorly understood. As pancreatic cancer (PC) is characterized by desmoplasia in the ECM, this study sought to assess the significance of keratocan in PC. Objective In this study, Gene Expression Profiling Interactive Analysis (GEPIA) was first used to analyze the expression pattern of keratocan in PC. Keratocan, P53, and P21 levels were evaluated in PDAC patient tissues and the role of keratocan was additionally directly assessed via transfecting PDAC cell lines with a pENTER-human keratocan construct. Results Patients with PC showing high levels of keratocan had low survival rates. A significantly upregulated expression of keratocan was observed in the PC tumor tissues in comparison to healthy paracancerous tissues. Keratocan upregulation in BxPC-3 and PANC-1 cells markedly enhanced their proliferation and migration, but reduced cellular apoptosis. Furthermore, the P53 and P21 expression levels were significantly reduced in pancreatic ductal adenocarcinoma cells overexpressing keratocan. P53 and P21 were downregulated in PC tumor tissues. Conclusions All results showed that keratocan played important roles in the promoting of PC. Background The role of the extracellular matrix (ECM) in oncogenic contexts has been studied previously, but the expression patterns and functional role of keratocan, a classical small leucine-rich proteoglycan found in the ECM, in tumors remain poorly understood. As pancreatic cancer (PC) is characterized by desmoplasia in the ECM, this study sought to assess the significance of keratocan in PC. Objective In this study, Gene Expression Profiling Interactive Analysis (GEPIA) was first used to analyze the expression pattern of keratocan in PC. Keratocan, P53, and P21 levels were evaluated in PDAC patient tissues and the role of keratocan was additionally directly assessed via transfecting PDAC cell lines with a pENTER-human keratocan construct. Results Patients with PC showing high levels of keratocan had low survival rates. A significantly upregulated expression of keratocan was observed in the PC tumor tissues in comparison to healthy paracancerous tissues. Keratocan upregulation in BxPC-3 and PANC-1 cells markedly enhanced their proliferation and migration, but reduced cellular apoptosis. Furthermore, the P53 and P21 expression levels were significantly reduced in pancreatic ductal adenocarcinoma cells overexpressing keratocan. P53 and P21 were downregulated in PC tumor tissues. Conclusions All results showed that keratocan played important roles in the promoting of PC.