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Morphology selective construction of

Maher Darwish, Ali Mohammadi, Navid Assi, Samer Abuzerr, Youssef Alahmad

《化学科学与工程前沿(英文)》 2020年 第14卷 第4期   页码 561-578 doi: 10.1007/s11705-019-1808-1

摘要: Controlled growth of Bi WO nanorods with exposed [0 0 1] facets and the fabrication of an Fe O -Bi WO magnetic composite by a microwave-assisted polyol process, were achieved in this study. The adsorptivity and photocatalytic performance of the composite toward sunset yellow dye degradation were greatly enhanced by the -cyclodextrin cavities on its surface, firmly anchored through a cetyltrimethylammonium bromide linkage. A series of examinations and characterizations were carried out to determine the influence of various factors on the morphological modulation-photocatalytic behavior of the pure Bi WO prior to final functionalization. Changing the pH of the precursor solution impacted the formation of 0D, 2D, and 3D structures; however, the presence of hexamethylenetetramine surfactant induced the development of 1D nanorod structure. A reasonable crystal growth mechanism was proposed to elucidate the formation process. Conversely, the mechanism of the activity enhancement of -cyclodextrin functionalized Fe O -Bi WO , compared to that of the non-functionalized samples, could be realized with the assistance of chemical trapping experiments on sunset yellow, and was confirmed on the colorless antibiotic (sulfamethoxazole). The high performance and durability of this composite can be attributed to the facet-dependent activity, large adsorption capacity due to inclusion interactions, enhanced visible light absorption, and efficient charge separation.

关键词: β-cyclodextrin     Bi2WO6     shape controlled     nanorod     sunset yellow    

Synthesis and characterization of biocompatible polyurethanes for controlled release of hydrophobic and

Juichen YANG,Hong CHEN,Yuan YUAN,Debanjan SARKAR,Jie ZHENG

《化学科学与工程前沿(英文)》 2014年 第8卷 第4期   页码 498-510 doi: 10.1007/s11705-014-1451-9

摘要: Design of biocompatible and biodegradable polymer systems for sustained and controlled release of bioactive agents is critical for numerous biomedical applications. Here, we designed, synthesized, and characterized four polyurethane carrier systems for controlled release of model drugs. These polyurethanes are biocompatible and biodegradable because they consist of biocompatible poly(ethylene glycol) or poly(caprolactone diol) as soft segment, linear aliphatic hexamethylene diisocyanate or symmetrical aliphatic cyclic dicyclohexylmethane-4,4′-diisocyanate as hard segment, and biodegradable urethane linkage. They were characterized with Fourier transform infrared spectroscopy, atomic force microscope, and differential scanning calorimetry, whereas their degradation behaviors were investigated in both phosphate buffered saline and enzymatic solutions. By tuning polyurethane segments, different release profiles of hydrophobic and hydrophilic drugs were obtained in the absence and presence of enzymes. Such difference in release profiles was attributed to a complex interplay among structure, hydrophobicity, and degradability of polyurethanes, the size and hydrophobicity of drugs, and drug-polymer interactions. Different drug-polyurethane combinations modulated the distribution and location of the drugs in polymer matrix, thus inducing different drug release mechanisms. Our results highlight an important role of segmental structure of the polyurethane as an engineering tool to control drug release.

关键词: phase structure     degradation     polyurethanes     controlled release     drug delivery    

An extended thermo-mechanically coupled algorithm for simulation of superelasticity and shape memoryeffect in shape memory alloys

S. HASHEMI,H. AHMADIAN,S. MOHAMMADI

《结构与土木工程前沿(英文)》 2015年 第9卷 第4期   页码 466-477 doi: 10.1007/s11709-015-0300-3

摘要: Thermo-mechanical coupling in shape memory alloys is a very complicated phenomenon. The heat generation/absorption during forward/reverse transformation can lead to temperature-dependent variation of its mechanical behavior in the forms of superelasticity and shape memory effect. However, unlike the usual assumption, slow loading rate cannot guarantee an isothermal process. A two-dimensional thermo-mechanically coupled algorithm is proposed based on the original model of Lagoudas to efficiently model both superelasticity and shape memory effects and the influence of various strain rates, aspect ratios and boundary conditions. To implement the coupled model into a finite element code, a numerical staggered algorithm is employed. A number of simulations are performed to verify the proposed approach with available experimental and numerical data and to assess its efficiency in solving complex SMA problems.

关键词: shape memory alloy     thermo-mechanical coupling     superplasticity     shape memory effect    

A novel shape memory alloy actuated soft gripper imitated hand behavior

《机械工程前沿(英文)》 2022年 第17卷 第4期 doi: 10.1007/s11465-022-0700-8

摘要: The limited length shrinkage of shape memory alloy (SMA) wire seriously limits the motion range of SMA-based gripper. In this paper, a new soft finger without silicone gel was designed based on pre bent SMA wire, and the finger was back to its original shape by heating SMA wire, rather than relying only on heat exchange with the environment. Through imitating palm movement, a structure with adjustable spacing between fingers was made using SMA spring and rigid spring. The hook structure design at the fingertip can form self-locking to further improve the load capacity of gripper. Through the long thin rod model, the relationship of the initial pre bent angle on the bending angle and output force of the finger was analyzed. The stress-strain model of SMA spring was established for the selection of rigid spring. Three grasping modes were proposed to adapt to the weight of the objects. Through the test of the gripper, it was proved that the gripper had large bending amplitude, bending force, and response rate. The design provides a new idea for the lightweight design and convenient design of soft gripper based on SMA.

关键词: shape memory alloy (SMA)     pre bent     wire     gripper     grasping mode     lightweight    

Size and shape effects of MnFeO nanoparticles as catalysts for reductive degradation of dye pollutants

《环境科学与工程前沿(英文)》 2021年 第15卷 第5期   页码 108-171 doi: 10.1007/s11783-021-1396-4

摘要: The magnetic nanoparticles that are easy to recycle have tremendous potential as a suitable catalyst for environmental toxic dye pollutant degradation. Rationally engineering shapes and tailoring the size of nanocatalysts are regarded as an effective manner for enhancing performances. Herein, we successfully synthesized three kinds of MnFe2O4 NPs with distinctive sizes and shapes as catalysts for reductive degradation of methylene blue, rhodamine 6G, rhodamine B, and methylene orange. It was found that the catalytic activities were dependent on the size and shape of the MnFe2O4 NPs and highly related to the surface-to-volume ratio and atom arrangements. Besides, all these nanocatalysts exhibit selectivity to different organic dyes, which is beneficial for their practical application in dye pollutant treatment. Furthermore, the MnFe2O4 NPs could be readily recovered by a magnet and reused more than ten times without appreciable loss of activity. The size and shape effects of MnFe2O4 nanoparticles demonstrated in this work not only accelerate further understanding the nature of nanocatalysts but also contribute to the precise design of nanoparticles catalyst for pollutant degradation.

关键词: Dye degradation     MnFe2O4 nanoparticles     Size and shape-control    

Size-controlled green synthesis of silver nanoparticles assisted by L-cysteine

Wenchao Zhang,Lin Zhang,Yan Sun

《化学科学与工程前沿(英文)》 2015年 第9卷 第4期   页码 494-500 doi: 10.1007/s11705-015-1527-1

摘要: A green and size-controlled synthesis of silver nanoparticles (Ag NPs) in aqueous solution with the assistance of L-cysteine is presented. The size of Ag NPs decreases with the increase of L-cysteine concentration, and thus can be controlled by adjusting L-cysteine concentration. TEM analysis shows that Ag NPs with an average size of 3 nm can be produced in the presence of 1.0 mmol/L L-cysteine, about one sixth of the size of Ag NPs obtained in the absence of L-cysteine (17 nm). The as-synthesized silver colloidal solution is stable and can be stored at room temperature for at least two months without any precipitation. This L-cysteine assisted method is simple, feasible and efficient, and would facilitate the production and application of Ag NPs.

关键词: nanoparticles     silver     L-cysteine     size distribution     synthesis    

Analysis and stabilization control of a voltage source controlled wind farm under weak grid conditions

《能源前沿(英文)》 2022年 第16卷 第6期   页码 943-955 doi: 10.1007/s11708-021-0793-5

摘要: This paper investigates and discusses the interaction stability issues of a wind farm with weak grid connections, where the wind turbines (WTs) are controlled by a new type of converter control strategy referred to as the voltage source (VS) control. The primary intention of the VS control method is to achieve the high-quality inertial response capability of a single WT. However, when it is applied to multiple WTs within a wind farm, its weak-grid performance regarding the stability remains concealed and needs to be clarified. To this end, a frequency domain model of the wind farm under the VS control is first developed. Based on this model and the application of a stability margin quantification index, not only the interactions between the wind farm and the weak grid but also those among WTs will be systematically assessed in this paper. A crucial finding is that the inertial response of VS control has negative impacts on the stability margin of the system, and the dominant instability mode is more related to the interactions among the WTs rather than the typical grid-wind farm interaction. Based on this knowledge, a stabilization control strategy is then proposed, aiming for stability improvements of VS control while fulfilling the demand of inertial responses. Finally, all the results are verified by time-domain simulations in power systems computer aided design/electromagnetic transients including DC(PSCAD/EMTDC).

关键词: weak grids     voltage source (VS) control     wind turbine (WT)     stabilization control     wind farm     inertial response    

Temperature effects of shape memory alloys (SMAs) in damage control design of steel portal frames

Xiaoqun LUO, Hanbin GE, Tsutomu USAMI

《结构与土木工程前沿(英文)》 2012年 第6卷 第4期   页码 348-357 doi: 10.1007/s11709-012-0176-4

摘要: The objective of the present study is to analytically investigate temperature effects of an axial-type seismic damper made of shape memory alloys (SMAs) equipped in steel frames. Based on a modified multilinear one dimensional constitutive model of SMAs, two types of SMAs are employed, which have different stress plateau and different stress growth rate with temperature increase. Temperature effects of SMA dampers on seismic performance upgrading are discussed in three aspects: different environment temperatures; rapid loading rate induced heat generation and different SMA fractions. The analysis indicates that the effect of environment temperature should be considered for the SMA damper in steel frames. However, the rapid loading rate induced heat generation has little adverse effect.

关键词: damage control design     shape memory alloy     temperature effect    

Chinese medicine patterns on patients with pneumoconiosis: a pilot double-blind, randomized, and placebo-controlled

《医学前沿(英文)》 2022年 第16卷 第5期   页码 736-744 doi: 10.1007/s11684-021-0870-5

摘要: Effective therapy options for pneumoconiosis are lacking. Traditional Chinese medicine (TCM) presents a favorable prospect in the treatment of pneumoconiosis. A pilot study on TCM syndrome differentiation can evaluate the clinical efficacy and safety of TCM and lay a foundation for further clinical research. A double-blind, randomized, and placebo-controlled trial was conducted for 24 weeks, in which 96 patients with pneumoconiosis were randomly divided into the control and treatment groups. Symptomatic treatment was conducted for the two groups. The treatment group was treated with TCM syndrome differentiation, and the control group was treated with placebo. The primary outcomes were the six-minute walking distance (6MWD) and the St. George Respiratory Questionnaire (SGRQ) score. The secondary outcomes were the modified British Medical Research Council Dyspnea Scale (mMRC), Chronic Obstructive Pulmonary Disease Assessment Test (CAT), Hospital Anxiety and Depression Scale (HADS), and pulmonary function. Only 83 patients from the 96 patients with pneumoconiosis finished the study. For the primary outcome, compared with the control groups, the treatment group showed a significantly increased 6MWD (407.90 m vs. 499.51 m; 95% confidence interval (CI) 47.25 to 135.97; P <0.001) and improved SGRQ total score (44.48 vs. 25.67; 95% CI −27.87 to −9.74; P <0.001). The treatment group also significantly improved compared with the control group on mMRC score (1.4 vs. 0.74; 95% CI −1.08 to −0.23; P =0.003), CAT score (18.40 vs. 14.65; 95% CI −7.07 to −0.43; P =0.027), and the total symptom score (7.90 vs. 5.14; 95% CI −4.40 to −1.12; P <0.001). No serious adverse events occurred. This study showed that TCM syndrome differentiation and treatment had a favorable impact on the exercise endurance and quality of life of patients with pneumoconiosis.

关键词: pneumoconiosis     randomized controlled trials     traditional Chinese medicine    

Applications of thermostatically controlled loads for demand response with the proliferation of variable

Meng SONG, Wei SUN

《能源前沿(英文)》 2022年 第16卷 第1期   页码 64-73 doi: 10.1007/s11708-021-0732-5

摘要: More flexibility is desirable with the proliferation of variable renewable resources for balancing supply and demand in power systems. Thermostatically controlled loads (TCLs) attract tremendous attentions because of their specific thermal inertia capability in demand response (DR) programs. To effectively manage numerous and distributed TCLs, intermediate coordinators, e.g., aggregators, as a bridge between end users and dispatch operators are required to model and control TCLs for serving the grid. Specifically, intermediate coordinators get the access to fundamental models and response modes of TCLs, make control strategies, and distribute control signals to TCLs according the requirements of dispatch operators. On the other hand, intermediate coordinators also provide dispatch models that characterize the external characteristics of TCLs to dispatch operators for scheduling different resources. In this paper, the bottom-up key technologies of TCLs in DR programs based on the current research have been reviewed and compared, including fundamental models, response modes, control strategies, dispatch models and dispatch strategies of TCLs, as well as challenges and opportunities in future work.

关键词: thermostatically controlled load     demand response     renewable energy     power system operation    

A fully solid-state cold thermal energy storage device for car seats using shape-memory alloys

《能源前沿(英文)》 2023年 第17卷 第4期   页码 504-515 doi: 10.1007/s11708-022-0855-3

摘要: Thermal energy storage has been a pivotal technology to fill the gap between energy demands and energy supplies. As a solid-solid phase change material, shape-memory alloys (SMAs) have the inherent advantages of leakage free, no encapsulation, negligible volume variation, as well as superior energy storage properties such as high thermal conductivity (compared with ice and paraffin) and volumetric energy density, making them excellent thermal energy storage materials. Considering these characteristics, the design of the shape-memory alloy based the cold thermal energy storage system for precooling car seat application is introduced in this paper based on the proposed shape-memory alloy-based cold thermal energy storage cycle. The simulation results show that the minimum temperature of the metal boss under the seat reaches 26.2 °C at 9.85 s, which is reduced by 9.8 °C, and the energy storage efficiency of the device is 66%. The influence of initial temperature, elastocaloric materials, and the shape-memory alloy geometry scheme on the performance of car seat cold thermal energy storage devices is also discussed. Since SMAs are both solid-state refrigerants and thermal energy storage materials, hopefully the proposed concept can promote the development of more promising shape-memory alloy-based cold and hot thermal energy storage devices.

关键词: shape-memory alloy (SMA)     elastocaloric effect (eCE)     cooled seat     cold thermal energy storage    

板形计法的定义及实验应用

张进之,段春华,朱健勤

《中国工程科学》 2001年 第3卷 第12期   页码 47-51

摘要:

板形测控数学模型、解析板形刚度理论和板形板厚协调规律的综合称为板形计法。采用两种实验方式验证了板形计法的正确性和实用性,其一是通过轧铝板实验,计算轧机板形刚度和轧件板形刚度,由实测铝板凸度验证板形刚度方程;其二是由CVC板形控制热连轧机实测数据,用离线计算自适应系数的方法验证板形测控数学模型。

关键词: 板形计法     板形刚度方程     测控数学模型     后计算     自适应    

All-in-one functional supramolecular nanoparticles based on pillar[5]arene for controlled generation,

《化学科学与工程前沿(英文)》 2023年 第17卷 第3期   页码 307-313 doi: 10.1007/s11705-022-2216-5

摘要: The storage and controlled release of singlet oxygen (1O2) have attracted increasing attention due to the wide application and microsecond lifetime of 1O2 in water. Herein we provide an integrated nanoplatform consisting of a diphenylanthracene derivative, a water-soluble pillar[5]arene and a photosensitizer tetrakis(4-hydroxyphenyl)porphyrin (TPP), that may provide the controlled generation, storage and release of singlet oxygen. We design a new diphenylanthracene derivative with two trimethylammonium bromide groups on both ends that can be well recognized by the pillar[5]arene. The formed nanocarriers can be used to load TPP through their supramolecular self-assembly. The resulting nanoparticles show good water-solubility and uniform spherical morphology. After laser irradiation (660 nm), the nanoparticles exhibit excellent ability for the generation and storage of 1O2. When the irradiated nanoparticles are heated above 80 °C, 1O2 can be released from the system. Therefore, in this paper we pioneer the use of noncovalent interaction to integrate the diphenylanthracene derivatives and photosensitizers into one functional system, which provides a new strategy for the controlled generation, storage and release of singlet oxygen. We believe this groundbreaking strategy will have a great potential in providing necessary amounts of 1O2 for the photodynamic therapy of tumors in dark.

关键词: storage and controlled release of singlet oxygen     supramolecular nanoparticles     noncovalent interactions     pillararenes     diphenylanthracene     photosensitizers    

Calculation method on shape finding of self-anchored suspension bridge with spatial cables

Yan HAN, Zhengqing CHEN, Shidong LUO, Shankui YANG

《结构与土木工程前沿(英文)》 2009年 第3卷 第2期   页码 165-172 doi: 10.1007/s11709-009-0021-6

摘要: Based on the spatial model, a reliable and accurate calculation method on the shape finding of self-anchored suspension bridge with spatial cables was studied in this paper. On the principle that the shape of the main cables between hangers is catenary, the iteration method of calculating the shapes of the spatial main cables under the load of hanger forces was deduced. The reasonable position of the saddle was determined according to the shape and the theoretical joint point of the main cables. The shapes of the main cables at completed cable stage were calculated based on the unchanging principle of the zero-stress lengths of the main cables. By using a numerical method combining with the finite element method, one self-anchored suspension bridge with spatial cables was analyzed. The zero-stress length of the main cables, the position of the saddle, and the pre-offsetting of the saddle of the self-anchored suspension bridge were given. The reasonable shapes of the main cables at bridge completion stage and completed cable stage were presented. The results show that the shape-finding calculation method is effective and reliable.

关键词: bridge engineering     self-anchored suspension bridges     special cables     shape-finding     calculation method    

Correction to: Highly degradable chitosan-montmorillonite (MMT) nanocomposite hydrogel for controlled

《环境科学与工程前沿(英文)》 2023年 第17卷 第8期 doi: 10.1007/s11783-023-1704-2

标题 作者 时间 类型 操作

Morphology selective construction of

Maher Darwish, Ali Mohammadi, Navid Assi, Samer Abuzerr, Youssef Alahmad

期刊论文

Synthesis and characterization of biocompatible polyurethanes for controlled release of hydrophobic and

Juichen YANG,Hong CHEN,Yuan YUAN,Debanjan SARKAR,Jie ZHENG

期刊论文

An extended thermo-mechanically coupled algorithm for simulation of superelasticity and shape memoryeffect in shape memory alloys

S. HASHEMI,H. AHMADIAN,S. MOHAMMADI

期刊论文

A novel shape memory alloy actuated soft gripper imitated hand behavior

期刊论文

Size and shape effects of MnFeO nanoparticles as catalysts for reductive degradation of dye pollutants

期刊论文

Size-controlled green synthesis of silver nanoparticles assisted by L-cysteine

Wenchao Zhang,Lin Zhang,Yan Sun

期刊论文

Analysis and stabilization control of a voltage source controlled wind farm under weak grid conditions

期刊论文

Temperature effects of shape memory alloys (SMAs) in damage control design of steel portal frames

Xiaoqun LUO, Hanbin GE, Tsutomu USAMI

期刊论文

Chinese medicine patterns on patients with pneumoconiosis: a pilot double-blind, randomized, and placebo-controlled

期刊论文

Applications of thermostatically controlled loads for demand response with the proliferation of variable

Meng SONG, Wei SUN

期刊论文

A fully solid-state cold thermal energy storage device for car seats using shape-memory alloys

期刊论文

板形计法的定义及实验应用

张进之,段春华,朱健勤

期刊论文

All-in-one functional supramolecular nanoparticles based on pillar[5]arene for controlled generation,

期刊论文

Calculation method on shape finding of self-anchored suspension bridge with spatial cables

Yan HAN, Zhengqing CHEN, Shidong LUO, Shankui YANG

期刊论文

Correction to: Highly degradable chitosan-montmorillonite (MMT) nanocomposite hydrogel for controlled

期刊论文