Chain Architecture Research Articles

Wideband and Efficient 256-GHz Subharmonic- Based FMCW Radar Transceiver in 130-nm SiGe BiCMOS Technology

This article proposes a fully integrated single-channel bistatic frequency-modulated continuous-wave (FMCW) radar transceiver (TRX) that operates at a center frequency of 256 GHz. The main focus of this work is to realize a wideband and efficient radar TRX that offers high resolution of target detection in the short-range FMCW radar sensing application. The radar TRX chip is designed and manufactured using the 130 nm silicon–germanium (SiGe) bipolar complementary metal-oxide-semiconductor (BiCMOS) technology which offers heterojunction bipolar transistors (HBTs) with <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$f_{\mathbf {T}}/f_{\mathbf {MAX}}$ </tex-math></inline-formula> of 300/500 GHz. The transmitter (TX) of the radar TRX is based on a fundamentally operated multiplier-by-8 chain architecture that offers a 3-dB bandwidth of around 65 GHz with a saturated output power of −5.4 dBm. On the other hand, the receiver (RX) is based on a subharmonic architecture that provides a conversion gain (CG) of 10.4 dB with an average noise figure (NF) of 23.5 dB. This TRX is realized with two integrated on-chip folded dipole antennas. The antenna offers high antenna gain and radiation efficiency due to the use of the selective localized backside etching (LBE) technique. This chip consumes 305 mW of power from a 3.3-V supply and occupies a silicon area of 3.3 mm2. The radar range measurement is performed in an anechoic chamber, and it shows the maximum dynamic range (DR) of around 34 dB at 1-m range of the target.

Acesso equitativo a vacinas: lições aprendidas e perspectivas futuras

Abstract Vaccination is an essential component of primary health care and coping with health emergencies. However, despite the progress from the last decades, important barriers persist resulting in lower access and disparities between the countries in the access to new vaccines. In this scenario, the World Health Organization (WHO) launched, in 2020, the Immunization Agenda for the 2021-2030 decade (AI2030). This article aims to discuss the main factors that affect access to vaccines and strategies to promote equity in access to them at global and national levels. These factors are multi-sectoral and need to be considered in both levels, with emphasis on financial and geographic barriers, infrastructure challenges, socioeconomic and cultural factors, public policies, and governance. The text points the need to remodel the global architecture of production chains and research and innovation centers, creating and/or strengthening existing ones in low- and middle-income countries. In addition, establishing new mechanisms and models for the production and commercialization of vaccines is necessary. The strategies adopted for accessing vaccines and other health technologies are at the center of the global health agenda debate.

Daisy chain architectures: from discrete molecular entities to polymer materials.

Daisy chain architectures, made by the self-complementary threading of an axle covalently linked to a macrocycle, represent a particularly intriguing family of supramolecular and mechanically interlocked (macro)molecules. In this review, we discuss their recent history, their modular chemical structures, and the various synthetic strategies to access them. We also detail how their internal sliding motions can be controlled and how their integration within polymers can amplify that motions up to the macroscopic scale. This overview of the literature demonstrates that the peculiar structure and dynamics of daisy chains have already strongly influenced the research on artificial molecular machines, with the potential to be implemented from nanometric switchable devices to mechanically active soft-matter materials.

Highly differentiated multi-stimuli-responsive fluorescence performance of tetraphenylethylene-containing styrene–maleic acid copolymers induced by macromolecular architecture control

TPE-containing styrene–maleic acid copolymers with a diverse chain architecture display highly differentiated fluorescence responsiveness to multiple stimuli.

Primary sulfonamide-functional polymers with controlled chain architectures by RAFT polymerisation

Diblock copolymers with precisely located sulfonamide groups were synthesized by RAFT polymerisation, either using an acrylamido sulfonamide monomer (SPA) or a sulfonamide-functional trithiocarbonate RAFT agent (S-CTA).

Integrated Production and Distribution Planning using Mathematical Model for Maximizing Profit

In three-dimensional concurrent engineering context, product, process, and supply chain designs are approached by the imperative of concurrency principle. The imperative of concurrency proposes product architecture and supply chain architecture conducted simultaneously. The detailed product design and production process design are conducted simultaneously. While manufacturing system design is conducted simultaneously with logistic system design. This study concerns on integrating production planning with distribution planning in a new plastic bags plant. Since the plant is relatively new, the number of orders is still scarce. Therefore, production planning becomes critical. Producing more products than required creates inventories while producing as many as the order required creates an intermittent production schedule. A mathematical is developed to simultaneously schedule production and distribution to maximize profit. The model provides solutions on the number of materials to be delivered, the number of products produced and delivered within its period for the planning horizon.

Influence of Molecular Weight on the Bead Foaming and Bead Fusion Behavior of Poly(butylene terephthalate) (PBT)

A current trend in the progress of bead foams is the use of engineering polymers (i.e., poly(butylene terephthalate) (PBT)), which are more temperature resistant than commodity polymers and thus offer new areas of application. Currently, foaming and molding of PBT bead foams seem to be possible only with an epoxy-based chain extender. This modification leads not only to an increase in molecular weight but also to a changed PBT chain architecture (i.e., branching or even cross-linking). Thereby, the crystallization behavior is considerably slowed down so that the time for chain interdiffusion across neighboring bead surfaces is prolonged. This study investigates the molecular weight influence separately. The crystallization behavior is controlled by varying the length of linear PBTs in such a way that different bead fusion phenomena result. With increasing molecular weight, a lower open cell content (OCC), and therefore a higher expansion behavior during thermomechanical analysis, was observed, which increases the contact area between the beads in the cavity during the steam chest molding process. Adding to the literature shown so far, this study shows that linear chemically unmodified PBT can also be processed into bead foam components using PBTs having a higher molecular weight.

Synergistic effect of star‐shaped architecture and poly(ethylene glycol) moieties on poly(lactic acid) stereocomplex crystallization behaviors

AbstractStereocomplex (sc) crystal formation represents an important strategy to improve the physical properties of poly(lactic acid) (PLA), including enhanced thermal resistance, anti‐hydrolysis and mechanical performance. Therefore, understanding and controlling the sc crystallization behaviors is an important and widely studied research topic. Herein, we investigate the cooperative effect of star‐shaped PLA chain topology and poly(ethylene glycol) incorporation on sc formation. We synthesize a series of poly(lactides), including poly(l‐lactic acid) (PLLA), poly(d‐lactic acid), star‐shaped PLLA and poly(d‐lactic acid)‐poly(ethylene glycol)‐poly(d‐lactic acid) (DED) triblock copolymer, via ring‐opening polymerization of lactide, followed by solution blending to form PLA stereocomplexes (scPLAs). The chemical structure of the prepared scPLAs is characterized by Fourier transform infrared and nuclear magnetic resonance, whereas the crystallization behavior and spherulite morphology are investigated by wide‐angle X‐ray diffraction, DSC and polarized optical microscopy. Linear PLLA/star‐shaped poly(d‐lactic acid) presents rapid crystallization behaviors and high crystallinity due to the excellent nucleation ability of star‐shaped chain topology. For isothermal crystallization, star‐shaped PLLA/DED exhibits the fastest crystallization kinetics, the highest crystallinity and the lowest crystallization half‐time of all samples. It is found that addition of poly(ethylene glycol) segments can increase chain mobility and backbone flexibility, further facilitating the crystallization of scPLA containing star‐shaped chain architecture. These results demonstrate an effective approach to cooperatively promote scPLA formation, with potential use for practical applications. © 2022 Society of Industrial Chemistry.

Chain Architecture Dependence of Morphology and Water Transport in Poly(fluorene alkylene)-Based Anion-Exchange Membranes

Chain Architecture Dependence of Morphology and Water Transport in Poly(fluorene alkylene)-Based Anion-Exchange Membranes

The Isolation, Structure Elucidation and Bioactivity Study of Chilensosides A, A1, B, C, and D, Holostane Triterpene Di-, Tri- and Tetrasulfated Pentaosides from the Sea Cucumber Paracaudina chilensis (Caudinidae, Molpadida).

Five new triterpene (4,4,14-trimethylsterol) di-, tri- and tetrasulfated pentaosides, chilensosides A (1), A1 (2), B (3), C (4), and D (5) were isolated from the Far-Eastern sea cucumber Paracaudina chilensis. The structures were established on the basis of extensive analysis of 1D and 2D NMR spectra and confirmed by HR-ESI-MS data. The structural variability of the glycosides concerned the pentasaccharide chains. Their architecture was characterized by the upper semi-chain consisting of three sugar units and the bottom semi-chain of two sugars. Carbohydrate chains of compounds 2-5 differed in the quantity and positions of sulfate groups. The interesting structural features of the glycosides were: the presence of two sulfate groups at C-4 and C-6 of the same glucose residue in the upper semi-chain of 1, 2, 4, and 5 and the sulfation at C-3 of terminal glucose residue in the bottom semi-chain of 4 that makes its further elongation impossible. Chilensoside D (5) was the sixth tetrasulfated glycoside found in sea cucumbers. The architecture of the sugar chains of chilensosides A-D (1-5), the positions of sulfation, the quantity of sulfate groups, as well as the aglycone structures, demonstrate their similarity to the glycosides of the representatives of the order Dendrochirotida, confirming the phylogenetic closeness of the orders Molpadida and Dendrochirotida. The cytotoxic activities of the compounds 1-5 against human erythrocytes and some cancer cell lines are presented. Disulfated chilensosides A1 (2) and B (3) and trisulfated chilensoside C (4) showed significant cytotoxic activity against human cancer cells.

산업연관분석을 이용한 라스트마일 배송산업 공급사슬구조의 탐색적 연구

The purpose of the study is to identify the degree of production induction effects and industrial synergy effects of the last mile delivery service industry. It also connects the industrial linkage structure of the last mile delivery industry with the concept of the supply chain. Ultimately, it identifies the structure of the service supply chain centered on the last mile delivery. It approaches research problems from a service science perspective. The philosophical basis of the study is the concept of service dominant logic. In addition, the research methodology is an inter-industry analysis of economics, and WIOD is used for analysis data. Petroleum product manufacturing and warehousing are the backward industries of the last mile delivery industry. And it seems clear that wholesale and retail industry are forward industries. Therefore, the last mile delivery industry plays a role in connecting the relationship between the supply industry, the manufacturing industry, and the distribution industry on the supply chain. In addition, the supply chain architecture of the last mile delivery service is significantly different from the existing manufacturing-oriented supply chain structure. Academically, the concept of a traditional manufacturing-oriented supply chain has been expanded to the service sector. And it identified the supply chain structure of the last mile delivery service. In practice, if a strategic industry is selected with limited resources, it will be an important indicator for determining investment priorities.

Application Analysis of Block Technology Based on Block Chain Computer Model in the False Identification of the Catalog List of the Financial Department of Multinational Companies

The financial data of some listed companies is not transparent enough, especially in financial-related management and program planning. In addition to legal and ethical constraints, with the continuous upgrading of blockchain technology, it is possible to explore the use of blockchain technology to lower the threshold for a certain number of investors to participate in corporate financial governance. Jointly supervising the capital flow of listed companies can ensure the safety of funds and improve the efficiency of capital use, thereby solving the problem of financial fraud of listed companies to a certain extent. The four core features of blockchain technology include decentralized distributed ledgers, consensus mechanisms, asymmetric encryption, and smart contracts. Exploring the feasibility and embedding path of chain technology in the capital supervision of listed companies will help to solve this problem. The integrated application of blockchain technology plays an important role in new technology innovation and industrial transformation. According to the unique technical characteristics of blockchain technology such as decentralization, nontampering, and traceability, combined with its application scenarios in the accounting field, it is hoped to use blockchain technology to solve problems such as information asymmetry and easy tampering of financial amounts from the source. Therefore, effective analysis can reduce the occurrence of financial fraud and fraud in listed companies, and blockchain technology has become a new way to prevent financial fraud in listed companies. This paper analyzes the classification and basic characteristics of blockchain, and studies the access mechanism and voting rules of candidate nodes based on the private chain architecture of the Raft distributed protocol to ensure the authenticity and real-time of financial information of listed companies and financial decisions. Improving the difficulty of financial fraud can provide good social and economic benefits.

Role of Short Chain Branching in Crystalline Model Polyethylenes

The role of short chain branches (SCBs) (C4H9) on the melt and crystalline properties of monodisperse polyethylene systems (C400H802) is investigated, using molecular dynamics simulations of a coarse-grained united-monomer model that represents a chemical monomer as one particle. A method is introduced, whereby SCBs are grown out of the linear backbone to minimize computational expense. Here, this concept is proven by introducing differing numbers (Nb = 0, 1, 2, 4, 10, and 20) of regularly spaced SCBs along the chain backbones and studying their influence on the melt and crystalline properties. By growing SCBs into the melt phase, it is demonstrated that they marginally perturb the original topology, justifying a relatively short equilibration time after growth. Upon crystallization, however, each system’s behavior differs considerably. Cooling and heating cycles are performed to study crystallization and melting at progressively slower rates. The crystalline morphology is observed to depend strongly on both cooling rate and number of branches along the linear backbone. In particular, the lamella thickness decreases systematically with both faster cooling and increasing SCB content. At the highest branch content, of one per 20 backbone carbons (Nb = 20), crystallization is almost entirely suppressed, whereas a small number of branches allows control over the average lamellar thickness. This observation, combined with a prudent method for equilibrating systems with SCBs, opens up opportunities to study more complex chain architectures and mimic industrial polyethylene morphologies.

Multi‐Responsive Jammed Micro‐Gels Ink: Toward Control over the Resolution and the Stability of 3D Printed Scaffolds

Abstract3D printing of hydrogels usually relies on a combination of fine‐tuned material chemistry and polymer chain architecture to obtain an ink with adequate yield‐stress flow, shear‐thinning, and self‐healing behavior. Recent approaches in hydrogel ink design include introduction of reversible covalent or supramolecular bonds or jamming of microparticles into a granular hydrogel. However, the dimensional stability of such systems is typically afforded by a post‐printing covalent cross‐linking step that impedes further on‐demand degradation of the scaffolds. Here, a jammed micro‐gels ink made of thermosensitive poly(N‐isopropylacrylamide) micro‐gels incorporating terpyridine ligand linkers are proposed as a 3D printable ink that is cured post‐printing by iron (II) cations for long‐term stabilization. The uncross‐linked micro‐gels ink exhibits the rheological characteristics of granular materials, meaning yield‐stress, shear‐thinning and fast recovery. Upon curing, iron (II)‐bis‐terpyridine coordination complexes between neighboring micro‐gels are formed. The supramolecular bonds are sufficiently strong and long‐lived to maintain scaffold integrity during manual handling or immersion in liquid medium for over two months. The thermosensitivity of the micro‐gels endows the printed construct with reversible and cyclable temperature‐induced resolution enhancement, while the supramolecular cross‐linking provides an asset of disintegration on‐demand. The proposed micro‐gel scaffolds are biocompatible, revealing the potential for biomedical applications and 4D bioprinting.

Chain Redistribution Stabilizes Coexistence Phases in Block Copolymer Blends.

The nanoscale morphologies of block copolymer (BCP) thin films are determined by chain architecture. Experimental studies of thin film blends of different BCP chain types have demonstrated that blending can stabilize new motifs, such as coexistence phases. Here, we deploy coarse-grained molecular dynamics (MD) simulations in order to better understand the self-assembly behavior of BCP blend thin films. We consider blends of lamella- and cylinder-forming BCP chains, studying their morphological makeup, the chain distribution within the morphology, and the underlying polymer chain conformations. Our simulations show that there are local concentration deviations at the scale of the morphological objects that dictate the local structure, and that BCP chains redistribute within the morphology so as to stabilize the structure. Underlying these effects are measurable distortions in the BCP chain conformations. The conformational freedom afforded by BCP blending stabilizes defects and allows coexistence phases to appear, while also leading to kinetic trapping effects. These results highlight the power of blending in designing the morphology that forms.

Coarse-Grained Simulation of Bottlebrush: From Single-Chain Properties to Self-Assembly.

Bottlebrush polymers consist of a linear backbone with densely grafted side chains. They are known to have a range of properties of interest, such as enhanced mechanical strength and rapid self-assembly into large domains, and have attracted attention as promising candidates for applications in photonics, lithography, energy storage, organic optoelectronics, and drug delivery. Here, we present a coarse-grained model of bottlebrush polymers that is able to reproduce their experimentally observed persistence lengths and chain conformations in the melt. The model is then used to investigate the morphologies of this class of materials for various chain architectures and grafting densities.

The Construction of Intelligent Supply Chain System for Agricultural Products Based on Improved Ant Colony Algorithm

With the rapid development of China itself, the supply chain system has become an effective tool to enhance economic competitiveness, and the intelligent supply chain system integrates innovative technologies such as the Internet, the Internet of Things, cloud computing, and big data into the industrial supply chain management. The ant colony algorithm shows super flexibility and robustness at the level of optimizing many combination problems; the intelligent supply chain architecture of agricultural products is essentially the rational allocation of resources, which is a dynamic combination of resources and tasks that combines a variety of combinations to select the most appropriate and optimal performance. In this paper, the architecture of the intelligent supply chain of agricultural products is studied in combination with the improved ant colony algorithm, and some improvement strategies are adopted to avoid falling into local optimization or local convergence in order to avoid falling into local optimization or local convergence. The improvements of the algorithm mainly include the following: improving the path search of individual ants, improving the pheromone update strategy, improving the selection probability, and improving the dynamic growth mechanism of ants. In this paper, the VRPTW mathematical model, the dataset TSPLIB, and the operation data of the intelligent supply chain of agricultural products are used for test verification; the results can be obtained by verifying the results of the experiment closer to the optimal solution, and the efficiency of the algorithm is significantly improved. Therefore, through the improvement and optimization of the ant colony algorithm, it is very suitable for solving and optimizing the intelligent supply chain system of agricultural products.

Li+ Transport in Single-Ion Conducting Side-Chain Polymer Electrolytes with Nanoscale Self-Assembly of Ordered Ionic Domains

Li-ion batteries based on organic liquid electrolytes have been commercialized for decades. However, the flammability of the liquid electrolyte and propensity for reaction with metallic lithium anodes warrants the study of alternative electrolyte materials to satisfy modern demands such as higher safety and energy density. Polymer electrolytes are less flammable than organic liquids, more easily processable than inorganic solids, and more inert toward lithium metal and electrochemical side reactions. But the ionic conductivity in common polymer electrolytes, such as poly(ethylene oxide)-based polymer electrolytes, is limited by the segmental relaxation of the polymer matrix that is solvating the lithium cation. Recently, metal ion-containing polymers with regulated, repeating chain architecture have drawn attention as ion conductors due to their ionic domain segregation. In this contribution, we investigate the ion transport mechanism in a series of metal ion-containing polymers with ionic groups located on the side chains to explore their potential as Li+ conductors. Four side-chain polymers having different numbers (n = 6, 10, 12, and 15) of methylene groups as side spacers between the polymer backbone and terminally bound anions, titrated with Li+ counterions, were synthesized and characterized. These polymers were found to have strong nanoscale phase segregation with predominantly 1-D ionic domains. Through dielectric spectroscopy analysis, their conductivity was found to be linearly scaled with the dielectric relaxation rate. Short side chains (n = 6) resulted in a slower dielectric relaxation rate and lower DC conductivity compared to polymers with longer side chains (n ≥ 10). The long-range Li+ transport in these polymers is found to be coupled to the ionic cluster relaxations.

Including the reefer chain into genuine beef cold chain architecture based on blockchain technology

Improving the cold chain system for perishable foods would both increase food safety by maintaining quality and reduce business operation costs by minimizing food loss from inappropriate management. This has led to various attempts to apply blockchain technology (BCT) to the food cold chain, such as IBM's FoodTrust and Alibaba's Food Trust Frameworks. This system is expected to guarantee food traceability and sustainability. In this research, we focused on the importance of maritime and aviation transportation in the entire supply chain, and we established the BCT-based beef cold chain system, which includes the reefer chain. Specifically, we raised the monitoring and physical infrastructure issues at the port (or airport) and maritime (aviation) transportation node and took these into consideration. Additionally, we conducted scenario analysis to investigate the effects of the suggested system. The amount of food losses and the associated greenhouse gas (GHG) emissions are calculated by different scenarios in accordance with the recall recovery time and node where a recall occurrence is recognized. For both import and export models, when the proposed BCT-based beef cold chain platform is applied, the number of discarded reefer containers and the associated GHG emissions go down by 42.1% and 21.8%, respectively. Interestingly, when we assumed the recall recognition stage was right after the defects occur, the largest effects of improving performance of the proposed platform were 48.3% in import (IM) node of the port level. These results will provide a needed solution for cold chain management at the government level and affirms the essential role of the port/airport in the cold chain.

Smart offload chain: a proposed architecture for blockchain assisted fog offloading in smart city

Blockchain enables smart contract for secure data transfer by which fog offloading servers can have trustworthy access control to work with data execution. When cloud is used for handling requests from mobile users, the attacker may perform denial of service attack and the same is possible at fog nodes and the same can be handled with the help of blockchain technology. In this paper, smart city application is discussed a use case study for blockchain based fog computing architecture. We propose a novel offload chain architecture for blockchain-based offloading in internet of things (IoT) networks where mobile devices can offload their data to fog servers for computation by an access control mechanism. The offload chain model using deep reinforcement learning (DRL) is proposed to improve the efficiency of blockchain based fog offloading amongst existing models.