The effect of chitosan (CS) coagulation bath on structure and performance of polylactic acid (PLA) microfiltration membrane

Fei Liu,Bing-Bing Li,De Sun,Fenggang Li,Xinyue Pei 한국화학공학회 2022 Korean Journal of Chemical Engineering Vol.39 No.5

Membrane hydrophilicity is a crucial factor in evaluating ultrafiltration processes. In this paper, chitosan(CS) was selected for the hydrophilic modification of the polylactic acid (PLA) membrane, and PLACS membranes wereprepared for the densification of the yeast solution. By non-solvent phase inversion method (NIPS), the PLACS microfiltrationmembranes were prepared by using chitosan (CS) acetic acid solution as the coagulation bath and glutaraldehydeas the crosslinking agent. PLACS membranes were characterized by water contact angle, porosity, pore sizedistribution, mechanical properties, ATR-FTIR, SEM, TGA and the ultrafiltration experiment. The viscosity of coagulationbath solution can severely influence the exchange rate of the solvent and the non-solvent as well during phaseinversion; therefore, it can regulate the precipitation kinetics and membrane morphology. The results showed that chitosan(CS) was presented as granular on the pore surfaces of the PLACS membranes. When chitosan (CS) contentincreased, gel rate became smaller and membrane forming process was prolonged; the porosity and pore size of thePLACS were increased compared to the polylactic acid (PLA) membrane, pure water flux increased from 90.31 L·m2·h1to 120.14 L·m2·h1, and yeast rejection rate increased from 75% to more than 90%.

An Automatic Assembly Control Method for Peg and Hole based on Multidimensional Micro Forces and Torques

Fei Shen,Zheng-Tao Zhang,De Xu,Juan Zhang,Wenrong Wu 한국정밀공학회 2019 International Journal of Precision Engineering and Vol.20 No.8

In this paper, an automatic assembly method for peg and hole based on multidimensional micro forces and torques is developed for satisfying the accurate and lossless assembly requirements. The relationship between the forces and torques from the force sensor and the attitudes deviation of peg and hole is discussed. Moreover, a novel method based on active constraint state for estimating the deviation angles between the peg and the hole through the toques exerted on the sensor is proposed. To achieve automated insertion and minimize the contact forces and torques in the meanwhile during the insertion process, a control strategy for controlling contact forces and torques is proposed by eliminating the position and attitudes deviation interactively. Related assembly experiments are conducted to verify the effectiveness of the proposed approaches.

Study of the Electric Field Screening Effect for Field Emitter Arrays

Nannan Li,Fei Yan,Shucai Pang,Lei Chen,Dazhi Jin,Wei Xiang,De Zhang,Jingyi Dai,Baoqing Zeng 한국물리학회 2015 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.66 No.8

Understanding the influence of the interaction of emitters on the field emission performance of a field emitter array is of great importance for the design of a multi-emitter device. In this work, a screening factor S is defined to quantify the effect of electric field screening due to the interaction of emitters in an array. A three-dimensional finite integration technique is used to study the electric field screening effect for Spindt-type field emitter arrays which have potential applications in flatscreen displays and high-power vacuum electronics. The dependences of the electric field screening on the tip-to-tip spacing, half-angle of the emitter, height of the emitter and radius of the tip’s curvature are analyzed. The effects of the variations in the size of the emitter’s geometry on the most efficient arrangement to achieve maximum emission efficiency in an array are discussed.

Novel Spintronic Responses of Novel Materials: A Tale of Two Systems

Paul Haney,Fei Xue,Duarte Pereira de Sousa,Jian-Ping Wang,Tony Low 한국자기학회 2021 한국자기학회 학술연구발표회 논문개요집 Vol.31 No.1

The discovery of new materials with unique magnetic ordering, crystal symmetries, and topological properties continues to stimulate the development of new spintronic devices. Spin-orbit coupling underlies many of the spintronic applications in materials, as it couples the electron spin with its real space motion and often plays a key role in determining the topological properties of a material’s electronic structure. In this talk we’ll describe the unique properties of two quite distinct materials systems: antiferromagnetic bilayer CrI3 and magnetic tunnel junctions composed of one or more magnetic Weyl semimetals. Bilayer CrI3 is a two-dimensional Van der Waals material in which two ferromagnetic CrI3 monolayers are coupled antiferromagnetically. We consider electron doped CrI3 and theoretically study the current-induced torques present in this material. In the purely antiferromagnetic state, the two individually inversion symmetry-broken layers of CrI3 form inversion partners, like the well-studied CuMnAs and MnAu. However, the exchange and anisotropy energies are similar in magnitude, unlike previously studied antiferromagnets in which the exchange energy is dominant. This difference leads to qualitatively different behaviors in this material. Using a combination of first-principles calculations of the spin-orbit torque and an analysis of the ensuing spin dynamics, we show that the deterministic electrical switching of the Néel vector is the result of damping like spin-orbit torque, which is staggered on the magnetic sublattices. We then present results on magnetic tunnel junctions composed of one or more magnetic Weyl semimetal layers. For an asymmetric magnetic tunnel junction containing a conventional ferromagnet and a magnetic Weyl semimetal contact, we find unique features of the spin transfer torque. The Weyl semimetal hosts chiral bulk states and topologically protected Fermi arc surface states which we find govern the voltage behavior and efficiency of the spin transfer torque. We discuss the existence of a large field-like torque acting on the magnetic Weyl semimetal, whose efficiency can exceed the theoretical maximum of conventional magnetic tunnel junctions. This large field-like torque is derived from the Fermi arc spin texture and displays a counter-intuitive dependence on the Weyl nodes separation. We finally consider a magnetic tunnel junction composed of two Weyl semimetal contacts. For this system, we show that chirality-magnetization locking leads to a gigantic tunneling magnetoresistance ratio, an effect that does not rely on spin filtering by the tunnel barrier. Our results shed light on the new physics of multilayered spintronic devices comprising of magnetic Weyl semimetals, which might open doors for new energy efficient spintronic devices.

Monosomal Karyotypes among 1147 Chinese Patients with Acute Myeloid Leukemia: Prevalence, Features and Prognostic Impact

Yang, Xiao-Fei,Sun, Ai-Ning,Yin, Jia,Cai, Cheng-Sen,Tian, Xiao-Peng,Qian, Jun,Chen, Su-Ning,Wu, De-Pei Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.11

A monosomal karyotype (MK), defined as ${\geq}2$ autosomal monosomies or a single monosomy in the presence of additional structural abnormalities, was recently identified as an independent prognostic factor conveying an extremely poor prognosis in patients with acute myeloid leukemia (AML). In the present study, after excluding patients with t(15;17), t(8;21), inv(16) and normal karyotypes, 324 AML patients with cytogenetic abnormalities were the main subject of analysis. The incidences of MK were 13% in patients aged 15 to 60 years and 18% in those between 15 and 88 years old. MK was much more prevalent among elderly patients (p < 0.001) and was significantly associated with the presence of -7, -5, del(5q), abn12p, abn17p, -18 or 18q-, -20 or 20q- and CK (for all p < 0.001 except for abn12p p=0.009), and +8 or +8q was less frequent in MK+ AML(p=0.007). No correlation was noted between monosomal karyotype and FAB subtype (p > 0.05); MK remained significantly associated with worse overall survival among patients with complex karyotype (p=0.032); A single autosomal monosomy contributed an additional negative effect in OS of patients with structural cytogenetic abnormalities (P=0.008). This report presents the prevalence, feature and prognostic impact of MK among a large series of Chinese AML patients from a single center for the first time.

Genetic Diversity and Evolutionary Relationships of Oryza Species with the B- and C-Genomes as Revealed by SSR Markers

( Ying Bao ),( Hai Fei Zhou ),( De Yuan Hong ),( Song Ge ) 한국식물학회 2006 Journal of Plant Biology Vol.49 No.5

Protection Against Helicobacter pylori Infection by a Trivalent Fusion Vaccine Based on a Fragment of Urease B-UreB414

Li Wang,Xiao-Fei Liu,Shi Yun,Xiao-Peng Yuan,Xu-Hu Mao,Chao Wu,Wei-Jun Zhang,Kai-Yun Liu,Gang Guo,Dong-Shui Lu,Wen-De Tong,Ai-Dong Wen,Quan-Ming Zou 한국미생물학회 2010 The journal of microbiology Vol.48 No.2

A multivalent fusion vaccine is a promising option for protection against Helicobacter pylori infection. In this study, UreB414 was identified as an antigenic fragment of urease B subunit (UreB) and it induced an antibody inhibiting urease activity. Immunization with UreB414 partially protected mice from H. pylori infection. Furthermore, a trivalent fusion vaccine was constructed by genetically linking heat shock protein A (HspA), H. pylori adhesin A (HpaA), and UreB414, resulting in recombinant HspA-HpaA-UreB414 (rHHU). Its protective effect against H. pylori infection was tested in BALB/c mice. Oral administration of rHHU significantly protected mice from H. pylori infection, which was associated with H. pylori-specific antibody production and Th1/Th2-type immune responses. The results show that a trivalent fusion vaccine efficiently combats H. pylori infection, and that an antigenic fragment of the protein can be used instead of the whole protein to construct a multivalent vaccine.

Acid-doped polyaniline membranes for solar-driven interfacial evaporation

Xia Li,Dongmin Yue,Fei Liu,Jingtong Yu,Bing-Bing Li,De Sun,Xin Ma 한국화학공학회 2023 Korean Journal of Chemical Engineering Vol.40 No.1

Interface solar desalination technology is an important green and sustainable strategy to solve the freshwater crisis. Herein, polyaniline (PANI) membranes were prepared by immersion precipitation phase inversion (NIPs) method and using for solar-driven water evaporation. To improve the light absorption rate of the PANI membrane, acid doping modification was carried out to the membrane. The results show that the polyaniline-p-toluene sulfonic acid (PANI-PTSA) membrane modified by p-toluene sulfonic acid (PTSA) has microporous structure, and the hydrophilicity was greatly improved after modification. The water evaporation rate and solar energy conversion efficiency of PANI-PTSA membrane were 1.38 kg/(m2h) and 80.7% under 1 kW/m2 sunlight irradiation, respectively, significantly improved compared to the original membrane. Due to the electrostatic repulsion effect of PANI-PTSA on anion charged SO − 3 , Na+ is separated from Cl−, which reduces the salt crystallization in the evaporator, indicating that PANI-PTSA membrane has certain salt resistance in solar desalination experiments. This work provides a simple method to prepare the PANI-PTSA membrane with high efficiency and salt resistance that has huge potential for practical application of interface solar desalination technology.

Pose Measuring and Aligning of a Micro Glass Tube and a Hole on the Micro Sphere

Fu-Dong Li,De Xu,Zheng-Tao Zhang,Ya-Li Shi,Fei Shen 한국정밀공학회 2014 International Journal of Precision Engineering and Vol. No.

To ensure high uniformity of the inner space of the hollow sphere after assembly, the glass tube must be inserted into the hole on thesphere towards the center of the sphere. This paper deals with the pose measuring of the hole on the sphere and the glass tube andpose aligning of the two objects. The sphere is 500 mm in diameter with a 20 mm hole on it, and the glass tube is 17 mm in diameter. Novel pose measuring method for the hole on the sphere and the glass tube is developed, using two microscopic cameras, each oneacquires a projection vector of the object to be measured. A plane containing the optical axis of the microscopic camera and the posevector of the object is determined, with the microscopic camera calibrated in advance. Pose vector of the object to be measured canbe calculated by the intersection of the two planes acquired by the two microscopic cameras. Error analysis of the pose measuringmethod is conducted and experimental results were consistent with analytical results. Less than 0.7o pose aligning error is achievedusing the proposed pose measuring method and pose aligning method.

Failure analysis of prestressed concrete containment vessels under internal pressure considering thermomechanical coupling

Wu Yu-Xiao,Fei Zi-Jian,Feng De-Cheng,Song Meng-Yan 한국원자력학회 2023 Nuclear Engineering and Technology Vol.55 No.12

After a loss of coolant accident (LOCA) in the prestressed concrete containment vessels (PCCVs) of nuclear power plants, the coupling of temperature and pressure can significantly affect the mechanical properties of the PCCVs. However, there is no consensus on how this coupling affects the failure mechanism of PCCVs. In this paper, a simplified finite element modeling method is proposed to study the effect of temperature and pressure coupling on PCCVs. The experiment results of a 1:4 scale PCCV model tested at Sandia National Laboratory (SNL) are compared with the results obtained from the proposed modeling approach. Seven working conditions are set up by varying the internal and external temperatures to investigate the failure mechanism of the PCCV model under the coupling effect of temperature and pressure. The results of this paper demonstrate that the finite element model established by the simplified finite element method proposed in this paper is highly consistent with the experimental results. Furthermore, the stress-displacement curve of the PCCV during loading can be divided into four stages, each of which corresponds to the damage to the concrete, steel liner, steel rebar, and prestressing tendon. Finally, the failure mechanism of the PCCV is significantly affected by temperature.