Theranostic Polyaminocarboxylate–Cyanine–Transferrin Conjugate for Anticancer Therapy and Near‐Infrared Optical Imaging

Iron chelation therapy has been recognized as a promising antitumor therapeutic strategy. Herein we report a novel theranostic agent for targeted iron chelation therapy and near‐infrared (NIR) optical imaging of cancers. The theranostic agent was prepared by incorporation of a polyaminocarboxylate‐based cytotoxic chelating agent (N‐NE3TA; 7‐[2‐[(carboxymethyl)amino]ethyl]‐1,4,7‐triazacyclononane‐1,4‐diacetic acid) and a NIR fluorescent cyanine dye (Cy5.5) onto a tumor‐targeting transferrin (Tf). The N‐NE3TA–Tf conjugate (without Cy5.5) was characterized and evaluated for antiproliferative activity in HeLa, HT29, and PC3 cancer cells, which have elevated expression levels of the transferrin receptor (TfR). The N‐NE3TA–Tf conjugate displayed significant inhibitory activity against all three cancer cell lines. The NIR dye Cy5.5 was then incorporated into N‐NE3TA–Tf, and the resulting cytotoxic and fluorescent transferrin conjugate N‐NE3TA–Tf–Cy5.5 was shown by microscopy to enter TfR‐overexpressing cancer cells. This theranostic conjugate has potential application for dual use in targeted iron chelation cancer therapy and NIR fluorescence imaging.     

ZSM-5分子筛在MTP反应中的催化性能

合成了3种不同晶粒尺寸的ZSM-5分子筛,并制得MTP催化剂,对ZSM-5分子筛催化剂在MTP反应中的性能进行系统研究。采用XRD、SEM、N2物理吸附和TGA等对ZSM-5分子筛催化剂进行表征,发现小晶粒的ZSM-5分子筛具有良好的抗积炭性能,在MTP反应中具有较高的稳定性。采用小晶粒分子筛制成的催化剂,考察反应工艺条件对催化剂催化性能的影响,结果表明,丙烯选择性随反应温度和空速提高而增加,降低反应压力和提高水醇质量比也有利于提高丙烯选择性,为调整MTP工艺的产物分布和优化反应工艺条件提供了技术依据。     

Polycarboxylate superplasticizers of acrylic acid–isobutylene polyethylene glycol copolymers: monomer reactivity ratios,copolymerization behavior and performance

Acrylic acid–isobutylene polyethylene glycol (AA-TPEG) copolymers are typical of polycarboxylate superplasticizers (PCEs). AA-TPEG copolymers are prepared via free-radical polymerization with potassium persulfate as the initiator. The obtained copolymers were characterized by gel permeation chromatography (GPC) and infrared spectra (FTIR). The GPC method can break through the former limitations of the instruments and receive instantaneous unreacted and instantaneous monomer concentrations and not the initial monomer feeds. Since TPEG monomer is highly bulky, the common calculation methods for determining monomer reactivity ratios in copolymerization based on terminal copolymerization equation are not suitable. However, this study created non-linear least squares curve fitting of terminal copolymerization equation (NLLSQ-T) and penultimate copolymerization equation (NLLSQ-P) methods, which used Python’s NumPy, SciPy, and SymPy libraries to generate code and did numerical computations, bringing greater accuracy of monomer reactivity ratios. The monomer reactivity ratios were calculated with Fineman–Ross, Kelen–Tüdös, YBR, NLLSQ-T, and NLLSQ-P methods and found to be r _AA = 10.888, r′ _AA = 1.131, r _TPEG = 0.012, and r′ _TPEG = 0.042 for AA-TPEG copolymers. Moreover, this study also explored specific copolymerization behavior of similar structure of copolymers with steric hindrance under penultimate copolymerization equation, such as dependence of the mole fractions in the copolymer on the mole fractions of unreacted monomers in solution, variation of copolymer compositions with conversion and sequence length distribution. The fluidity and flow loss of pastes containing PCEs were investigated, and the appropriate PCEs dosages resulted in a better workability of cement pastes.     

基于数值模拟的太阳能直拉硅单晶热场降耗研究

通过计算机数值模拟仿真技术分析了TDR-95A-ZJS型22英寸太阳能直拉硅单晶热场结构中影响能耗的主要因素。基于模拟结果提出了通过改变部分热场结构及保温毡布局等优化措施可有效降低原有热场功耗。实际生产实验表明,优化后的热场在保证晶体生长原有质量前提下较原有热场节能29%。     

Coach simplified structure modeling and optimization study based on the PBM method

For the coach industry, rapid modeling and efficient optimization methods are desirable for structure modeling and optimization based on simplified structures, especially for use early in the concept phase and with capabilities of accurately expressing the mechanical properties of structure and with flexible section forms. However, the present dimension-based methods cannot easily meet these requirements. To achieve these goals, the property-based modeling (PBM) beam modeling method is studied based on the PBM theory and in conjunction with the characteristics of coach structure of taking beam as the main component. For a beam component of concrete length, its mechanical characteristics are primarily affected by the section properties. Four section parameters are adopted to describe the mechanical properties of a beam, including the section area, the principal moments of inertia about the two principal axles, and the torsion constant of the section. Based on the equivalent stiffness strategy, expressions for the above section parameters are derived, and the PBM beam element is implemented in HyperMesh software. A case is realized using this method, in which the structure of a passenger coach is simplified. The model precision is validated by comparing the basic performance of the total structure with that of the original structure, including the bending and torsion stiffness and the first-order bending and torsional modal frequencies. Sensitivity analysis is conducted to choose design variables. The optimal Latin hypercube experiment design is adopted to sample the test points, and polynomial response surfaces are used to fit these points. To improve the bending and torsion stiffness and the first-order torsional frequency and taking the allowable maximum stresses of the braking and left turning conditions as constraints, the multi-objective optimization of the structure is conducted using the NSGA-II genetic algorithm on the ISIGHT platform. The result of the Pareto solution set is acquired, and the selection strategy of the final solution is discussed. The case study demonstrates that the mechanical performances of the structure can be well-modeled and simulated by PBM beam. Because of the merits of fewer parameters and convenience of use, this method is suitable to be applied in the concept stage. Another merit is that the optimization results are the requirements for the mechanical performance of the beam section instead of those of the shape and dimensions, bringing flexibility to the succeeding design.     

Vehicle active steering control research based on two-DOF robust internal model control

Because of vehicle’s external disturbances and model uncertainties, robust control algorithms have obtained popularity in vehicle stability control. The robust control usually gives up performance in order to guarantee the robustness of the control algorithm, therefore an improved robust internal model control(IMC) algorithm blending model tracking and internal model control is put forward for active steering system in order to reach high performance of yaw rate tracking with certain robustness. The proposed algorithm inherits the good model tracking ability of the IMC control and guarantees robustness to model uncertainties. In order to separate the design process of model tracking from the robustness design process, the improved 2 degree of freedom(DOF) robust internal model controller structure is given from the standard Youla parameterization. Simulations of double lane change maneuver and those of crosswind disturbances are conducted for evaluating the robust control algorithm, on the basis of a nonlinear vehicle simulation model with a magic tyre model. Results show that the established 2-DOF robust IMC method has better model tracking ability and a guaranteed level of robustness and robust performance, which can enhance the vehicle stability and handling, regardless of variations of the vehicle model parameters and the external crosswind interferences. Contradiction between performance and robustness of active steering control algorithm is solved and higher control performance with certain robustness to model uncertainties is obtained.     

Research on the impact of service provider cooperative relationship on cloud manufacturing platform

As an emerging service-oriented manufacturing paradigm, Cloud Manufacturing (CMfg) is expected to provide smart networked platforms that enable efficient global collaborations among cloud service providers in a product lifecycle. The service provider cooperative relationship (SPCR) plays a crucial part in cloud service scheduling and thus potentially influences the operational performance of a CMfg platform. The guaranteed SPCR could ensure service quality and reduce the interaction costs among service providers in the process of collaborative manufacturing tasks, thereby having a positive impact on the operational efficiency of a CMfg platform. The cost reduction and quality assurance, however, usually make the cost-effective services more attractive for an increasing number of manufacturing tasks and lead to load imbalance in a CMfg platform, thus having a negative impact on the operational efficiency. The impact mechanism of SPCR on a CMfg platform is still unclear from an evolutionary perspective. In this paper, we propose a CMfg platform evolution model (CPEM) to investigate the impacts of SPCR on the operational performance of a CMfg platform. Three quantitative metrics, from the perspective of cloud consumer, cloud operator, and cloud service provider, respectively, are established to support the performance evaluation. The results of contrast experiments reveal the impacts of SPCR on a CMfg platform.     

Accessible regions of tool orientations in multi-axis milling of blisks with a ball-end mill

Noninterference tool orientations are hard to be determined in multi-axis milling of blisks, because the integrated structure of blisks introduces more geometrical constraints. To address this problem, an original approach without interference detection is proposed to solve accessible regions of tool orientations in milling of blisks. Based on the visibility of checking surfaces, only critical points on surface profiles are searched and processed to construct the accessible regions. In this approach, the start point of each profile is sought on boundaries of the main surface with a constant step length. From this point, a new critical point is first searched along a specified direction and then adjusted iteratively until it locates on a profile. When all critical points on profiles are searched like this, the searched points on each checking surface are reordered to form one or more than one closed curve to present the accessible region related to this checking surface. These curves are then mapped onto a unit sphere and divided into nonintersecting segments. After that, a concise approach is proposed to combine accessible regions of all checking surfaces into simply connected regions. This algorithm is finally verified with two kinds of blisks and compared with a referenced method. The results show that the proposed method can efficiently solve accessible regions in multi-axis milling of blisks with an expected accuracy.     

Regulation Mechanism of Novel Thermomechanical Treatment on Microstructure and Properties in Al-Zn-Mg-Cu Alloy

Scanning electron microscopy, transmission electron microscopy, tensile test, exfoliation corrosion test, and slow strain rate tensile test were applied to investigate the properties and microstructure of Al-Zn-Mg-Cu alloy processed by final thermomechanical treatment, retrogression reaging, and novel thermomechanical treatment (a combination of retrogression reaging with cold or warm rolling). The results indicate that in comparison with conventional heat treatment, the novel thermomechanical treatment reduces the stress corrosion susceptibility. A good combination of mechanical properties, stress corrosion resistance, and exfoliation corrosion resistance can be obtained by combining retrogression reaging with warm rolling. The mechanism of the novel thermomechanical treatment is the synergistic effect of composite microstructure such as grain morphology, dislocation substructures, as well as the morphology and distribution of primary phases and precipitations.     

冗余捷联惯组故障诊断的奇异值分解新方法*

冗余捷联惯组故障诊断奇异值分解法由于缺少单位化、阈值偏大和隔离策略有缺陷,导致漏警率偏高、误隔离率偏高且无法隔离负向故障。在分析Shim法原理的基础上,采用改进的解耦矩阵、新的故障隔离函数包含单位化和取模的运算,并且将故障检测和隔离分步实施。对改进方法进行蒙特卡洛数字仿真,仿真试验结果表明:新方法克服了Shim法的缺点,具有更高的正检率、更低的误隔离率。尤其对于发生负向故障的器件,改进方法能得到约99%的隔离率。新方法为冗余捷联惯组故障诊断提供一种新思路。