Independent Units Research Articles

BCAN: Bidirectional Correct Attention Network for Cross-Modal Retrieval.

As a fundamental topic in bridging the gap between vision and language, cross-modal retrieval purposes to obtain the correspondences' relationship between fragments, i.e., subregions in images and words in texts. Compared with earlier methods that focus on learning the visual semantic embedding from images and sentences to the shared embedding space, the existing methods tend to learn the correspondences between words and regions via cross-modal attention. However, such attention-based approaches invariably result in semantic misalignment between subfragments for two reasons: 1) without modeling the relationship between subfragments and the semantics of the entire images or sentences, it will be hard for such approaches to distinguish images or sentences with multiple same semantic fragments and 2) such approaches focus attention evenly on all subfragments, including nonvisual words and a lot of redundant regions, which also will face the problem of semantic misalignment. To solve these problems, this article proposes a bidirectional correct attention network (BCAN), which introduces a novel concept of the relevance between subfragments and the semantics of the entire images or sentences and designs a novel correct attention mechanism by modeling the local and global similarity between images and sentences to correct the attention weights focused on the wrong fragments. Specifically, we introduce a concept about the semantic relationship between subfragments and entire images or sentences and use this concept to solve the semantic misalignment from two aspects. In our correct attention mechanism, we design two independent units to correct the weight of attention focused on the wrong fragments. Global correct unit (GCU) with modeling the global similarity between images and sentences into the attention mechanism to solve the semantic misalignment problem caused by focusing attention on relevant subfragments in irrelevant pairs (RI) and the local correct unit (LCU) consider the difference in the attention weights between fragments among two steps to solve the semantic misalignment problem caused by focusing attention on irrelevant subfragments in relevant pairs (IR). Extensive experiments on large-scale MS-COCO and Flickr30K show that our proposed method outperforms all the attention-based methods and is competitive to the state-of-the-art. Our code and pretrained model are publicly available at: https://github.com/liuyyy111/BCAN.

Choosing allowability boundaries for describing objects in subject areas

Anomaly detection is one of the most promising problems for study and can be used as independent units and preprocessing tools before solving any fundamental data mining problems. This article proposes a method for detecting specific errors with the involvement of experts from subject areas to fill knowledge. The proposed method about outliers hypothesizes that they locate closer to logical boundaries of intervals derived from pair features, and the interval ranges vary in different domains. We construct intervals leveraging pair feature values. While forming knowledge in a specific field, a domain specialist checks the logical allowability of objects based on the range of the intervals. If the objects are logical outliers, the specialist ignores or corrects them. We offer the general algorithm for the formation of the database based on the proposed method in the form of a pseudo-code, and we provide comparison results with existing methods.

Low-order gray-box modeling of heating buildings and the progressive dimension reduction identification of uncertain model parameters

Heating buildings have a huge heat capacity and have abilities to accept fluctuating heat supply from renewables. Creating a low-order scalable model that describes the thermal dynamics of coupled heat transfer, charge, and discharge processes among heating buildings is essential to unlocking the thermal storage potential of building mass and achieving space heating decarbonization. White-box models tend to be too complex and black-box models lack scalability. Thus, a low-order gray-box model with uncertain lumped parameters is proposed based on comprehensive heat transfer analyses and necessary assumptions. Thermal mass in heating buildings is divided into four independent heat storage units. The building envelope that can be heated directly or not is regarded as a different heat storage unit. To reduce the search space dimension of model identification, the decision variables are downsized to essential model parameters based on the sensitivity analysis. Moreover, a progressive dimension reduction method is introduced to further improve the probability that the optimization algorithm converges to a global minimum. Case studies show that the calibrated model with global optimal solutions of uncertain model parameters has a good performance on the prediction of the average temperature of indoor air, the average absolute error is only 0.1 °C.

Population genetic structure in the critically endangered Crocodylus intermedius (Crocodilia: Crocodylidae): a shift in perspective for conservation actions in Colombia

Abstract Conservation actions for threatened species and populations aim to preserve their genetic diversity and prevent issues such as inbreeding or outbreeding depressions. This perspective has been incorporated into the management plans proposed for the critically endangered Orinoco crocodile (Crocodylus intermedius) in Colombia. A previous study, which used mitochondrial cytochrome b and cytochrome c oxidase subunit I, suggested that the in situ population management of the Orinoco crocodile in Colombia does not face genetic restrictions. In this research, we re-evaluated this proposal by using an expanded sampling and additional molecular markers (microsatellite nuclear DNA and the mitochondrial D-loop) that have successfully identified crucial information at the population level in other crocodilians. Our findings reveal, for the first time, a pattern of population structure consisting of three genetic clusters with geographical correspondence, matching three ecoregions in the Colombian Orinoco basin. This pattern might be a historical and current consequence of the ecological, bioclimatic, and/or geographical features of the ecoregion. Additionally, we examined the correspondence with the genetic clusters of the confiscated individuals that formed part of the initial population (F0) of the Colombian ex situ species population and successfully assigned most of them to one of these clusters. The genetically distinct clusters should be regarded as independent management units for conserving and managing the species in Colombia.

A generalized model for monitor units determination in ocular proton therapy using machine learning: A proof-of-concept study

Objective. Determining and verifying the number of monitor units is crucial to achieving the desired dose distribution in radiotherapy and maintaining treatment efficacy. However, current commercial treatment planning system(s) dedicated to ocular passive eyelines in proton therapy do not provide the number of monitor units for patient-specific plan delivery. Performing specific pre-treatment field measurements, which is time and resource consuming, is usually gold-standard practice. This proof-of-concept study reports on the development of a multi-institutional-based generalized model for monitor units determination in proton therapy for eye melanoma treatments. Approach. To cope with the small number of patients being treated in proton centers, three European institutes participated in this study. Measurements data were collected to address output factor differences across the institutes, especially as function of field size, spread-out Bragg peak modulation width, residual range, and air gap. A generic model for monitor units prediction using a large number of 3748 patients and broad diversity in tumor patterns, was evaluated using six popular machine learning algorithms: (i) decision tree; (ii) random forest, (iii) extra trees, (iv) K-nearest neighbors, (v) gradient boosting, and (vi) the support vector regression. Features used as inputs into each machine learning pipeline were: Spread-out Bragg peak width, range, air gap, fraction and calibration doses. Performance measure was scored using the mean absolute error, which was the difference between predicted and real monitor units, as collected from institutional gold-standard methods. Main results. Predictions across algorithms were accurate within 3% uncertainty for up to 85.2% of the plans and within 10% uncertainty for up to 98.6% of the plans with the extra trees algorithm. Significance. A proof-of-concept of using machine learning-based generic monitor units determination in ocular proton therapy has been demonstrated. This could trigger the development of an independent monitor units calculation tool for clinical use.

MiRNAs differentially expressed in vegetative and reproductive organs of Marchantia polymorpha – insights into their expression pattern, gene structures and function

ABSTRACT MicroRNAs regulate gene expression affecting a variety of plant developmental processes. The evolutionary position of Marchantia polymorpha makes it a significant model to understand miRNA-mediated gene regulatory pathways in plants. Previous studies focused on conserved miRNA-target mRNA modules showed their critical role in Marchantia development. Here, we demonstrate that the differential expression of conserved miRNAs among land plants and their targets in selected organs of Marchantia additionally underlines their role in regulating fundamental developmental processes. The main aim of this study was to characterize selected liverwort-specific miRNAs, as there is a limited knowledge on their biogenesis, accumulation, targets, and function in Marchantia. We demonstrate their differential accumulation in vegetative and generative organs. We reveal that all liverwort-specific miRNAs examined are encoded by independent transcriptional units. MpmiR11737a, MpmiR11887 and MpmiR11796, annotated as being encoded within protein-encoding genes, have their own independent transcription start sites. The analysis of selected liverwort-specific miRNAs and their pri-miRNAs often reveal correlation in their levels, suggesting transcriptional regulation. However, MpmiR11796 shows a reverse correlation to its pri-miRNA level, suggesting post-transcriptional regulation. Moreover, we identify novel targets for selected liverwort-specific miRNAs and demonstrate an inverse correlation between their expression and miRNA accumulation. In the case of one miRNA precursor, we provide evidence that it encodes two functional miRNAs with two independent targets. Overall, our research sheds light on liverwort-specific miRNA gene structure, provides new data on their biogenesis and expression regulation. Furthermore, identifying their targets, we hypothesize the potential role of these miRNAs in early land plant development and functioning.

Intermediate product control in cascade reaction for one-pot production of ε-caprolactone by Escherichia coli.

ε-Caprolactone is an important non-toxic compound for polymer synthesis like polycaprolactone which has been widely used in drug delivery and degradable plastics. To meet the demand for a green economy, a bi-enzymatic cascade, consisting of an alcohol dehydrogenase (ADH) and a cyclohexanone monooxygenase (CHMO), was designed and introduced into Escherichia coli to synthesize ε-caprolactone from cyclohexanol with a self-sufficient NADPH-cofactor regeneration system. To further improve the catalytic efficiency, a carbonyl group-dependent colorimetric method using inexpensive 2,4-dinitrophenylhydrazine (DNPH) was developed for assay of cyclohexanone, an intermediate production of cascade reaction. It can be used to screen mutant strains with high catalytic efficiency from high-throughput library by detecting the absorbance value in microtiter plates (MTP) instead of gas chromatography (GC) analysis. Moreover, an RBS combinatorial library was constructed for balancing the expression of ADH and CHMO from two independent transcriptional units. After the high-throughput screening based on intermediate product control, an optimal variant with higher substrate tolerance and long-term stability was obtained from RBS combinatorial library. Through a fed-batch process, ε-caprolactone production reached 148.2mM after 70h of reaction under the optimized conditions, which was the highest yield achieved to date.

A Geostratigraphic Map of the Rachmaninoff Basin Area: Integrating Morphostratigraphic and Spectral Units on Mercury

AbstractGeological maps of Earth typically incorporate field observations of rock lithology, structure, composition, and more. In contrast, conventional planetary geological maps are often made using primarily qualitative morphostratigraphic remote sensing observations of planetary surfaces. However, it is possible to define independent quantitative spectral units (SUs) of planetary surfaces, which potentially contain information about surface composition, grain size, and space weathering exposure. Here, we demonstrate a generic method to combine independently derived geomorphic and SUs, using the Rachmaninoff basin, Mercury, as an example to create a new geostratigraphic map. From this geostratigraphic map, we can infer some compositional differences within geomorphic units, which clarifies and elaborates on the geological evolution of the region.

A Comprehensive Review on Creating Autonomous Car Systems

Autonomous vehicles are around us and are finding trillions of recent developed applications, starting from driverless cars to automatically observation in critical areas. Continual progress in these technologies within the earlier decades makes these inventions possible. However, the planning of these technologies which must be surmounted, to apply efficient, useful supremely important and safe tasks of those independent units are daunting as well as numerous. Over the past decade, many researches are published within the domain of autonomous vehicles. Yet, most of them concentrate only on a selected technological area, such as vehicle control, visual environment perception ... etc. During this paper we present a brief yet comprehensive overview on the most significant key ingredients of autonomous cars, it covers almost all bases, from available models and types, their functions, importance, in addition to the most important related work.

Centers of responsibility for the formation of effective activities of enterprises of the grain product complex

Introduction. To ensure the efficiency of enterprises, it is important to form responsibility centers. They will be responsible for the performance of enterprises. These processes are intensified under the influence of the war in Ukraine and due to the negative consequences of the Covid-19 pandemic. Global changes that have occurred in the external environment require a revision of approaches to the formation of efficiency of enterprises in general, as well as their structural divisions. The purpose of the paper is to research the centers of responsibility in the enterprise management system of the grain production complex. Results. The authors defend the thesis that responsibility centers solve the tasks of coordinating, distributing responsibilities and stimulating all units to achieve the strategic goals of the enterprise. It is necessary to consider the centers of responsibility as structural divisions of the enterprise, since the transformation of the organizational system of the enterprise is constant. That is, the allocation of responsibility centers occurs within a specially created structure that does not coincide with the organizational structure of the enterprise. The authors will give on a concrete example the performance indicators of the enterprise of the grain production complex for Volyn-Zerno-Product LLC. On this basis, conclusions are drawn about positive or negative trends that affect the efficiency of enterprises. In particular, positive changes are the growth of current and non-current assets, receivables, and negative ones are the increase in production costs, payables, a decrease in cash, a slowdown in asset turnover, low liquidity indicators, and financial stability. To overcome negative trends, it is necessary to develop measures to improve performance. One of the areas of increasing the effectiveness of Volyn-Grain-Product LLC is the formation of responsibility centers: costs, revenues, profits, investments. Conclusion. The use of responsibility centers will distinguish between the main functions, powers, rights and responsibilities through which the activities of enterprises of the grain production complex are carried out. Departments or business processes in this situation are independent units of the process, and managers are responsible for the implementation of planned indicators.

The use of Versius CMR for pelvic surgery: a multicentric analysis of surgical setup and early outcomes

IntroductionVersius CMR is a novel robotic system characterized by an open surgical console and independent bedside units. The system has potentials of flexibility and versatility, and has been used in urological, gynecological, and general surgical procedure. The aim is to depict a comprehensive analysis of the Versius system for pelvic surgery.MethodsThis is a study involving two Institutions, ASST Santi Paolo and Carlo, Milan, and Apuane Hospital, Massa, Italy. All interventions performed in the pelvic area with the Versius were included. Data about indications, intra-, and post-operative course were prospectively collected and analyzed.ResultsA total of 171 interventions were performed with the Versius. Forty-two of them involved pelvic procedures. Twenty-two had an oncological indication (localized prostate cancer), the remaining had a non-oncological or functional purpose. The mostly performed pelvic procedure was radical prostatectomy (22) followed by annexectomy (9). No intra-operative complication nor conversion to other approaches occurred. A Clavien II complication and one Clavien IIIb were reported. Malfunctioning/alarms requiring a power cycle of the system occurred in 2 different cases. An adjustment in trocar placement according to patients’ height was required in 2 patients undergoing prostatectomy, in which the trocar was moved caudally. In two cases, a pelvic prolapse was repaired concomitant with other gynecological procedures.ConclusionsPelvic surgery with the Versius is feasible without major complications; either dissection and reconstructive steps could be accomplished, provided a proper OR setup and trocar placement are pursued. Versius can be easily adopted by surgeons of different disciplines and backgrounds; a further multi-specialty implementation is presumed and long-term oncological and functional outcomes are awaited.

An efficient wastewater collection model for groundwater resource protection in smart cities

Efficient wastewater collection is a critical concern in the development of smart cities, where sustainable urban infrastructure is paramount. In the context of smart city wastewater optimization, this study highlights the need for a comprehensive approach that considers both surface water and groundwater dynamics. Existing methods often fall short in addressing groundwater-related concerns, with limitations in accounting for potential contamination and aquifer vulnerability. The proposed method integrates a nuanced understanding of groundwater aspects, providing a more robust and sustainable solution for urban water resource management. This research introduces a new approach that harnesses the power of Divide-And-Conquer (DAC) and Variable Neighborhood Search (VNS) to optimize wastewater collection systems in smart cities. The DAC strategy divides the city into manageable zones, simplifying the optimization problem for parallel processing in large-scale urban environments. VNS fine-tunes wastewater collection networks within each zone by exploring diverse neighborhood solutions. The DAC and VNS offers several benefits, including improved efficiency in wastewater transport, reduced energy consumption, and minimized environmental impact. Zoning the urban landscape is a strategic approach to optimize wastewater collection in smart cities. It involves dividing the city into manageable zones based on specific criteria such as geographical features, population density, and infrastructure layout. Each zone is treated as an independent unit for focused analysis and optimization. The optimization process employs a scoring function that combines weighted criteria, yielding a composite score for each geographical location. Applying a threshold or clustering algorithm group's locations into zones, facilitating tailored wastewater management strategies. By optimizing collection routes and infrastructure design, this approach assists smart cities in achieving sustainability goals while efficiently managing wastewater. The study showcases the potential of DAC and VNS as a robust and adaptable solution for wastewater collection in smart cities, contributing to the development of greener, more resource-efficient urban areas.

A genomic approach for the identification of population management units for the dolphinfish (Coryphaena hippurus) in the eastern Pacific

In the Tropical Eastern Pacific dolphinfish (TEP) Corypahena hippurus is part of commercial, recreational, and artisanal fisheries and is also caught incidentally by the tuna purse-seine and longline fisheries. Defining the existence of differenced populations in exploited species for being considered independent management units is crucial for conservation plans. However, there is a great uncertainty about the species population genetic structure across the TEP. To investigate it and to identify possible management units for conservation purposes this study was carried out, based on two SNPs datasets of 3867 and 3220 SNPs for young of the year (YOY) and adult individuals, respectively, obtained through NGS protocols. Sampling covered the species’ range distribution in the Tropical Eastern Pacific and was structured into YOY and adult individuals in order to discard the effects of migrating individuals into sampled locations. Our results revealed slight but significant differences among locations occupying the latitudinal limits of the species distribution at transitional areas between tropical and subtropical waters. These areas are characterized by strong seasonal variations in sea surface temperature and limit the prevalence of populations in these extremes. Genetic differences also seem to be related to spatial separation of locations as the northernmost (Los Cabos) and southernmost (Peru) locations including a set of oceanic samples, showed the highest levels of genetic differentiation. Whereas were detected barriers to gene flow among spatially separated locations for YOY individuals probably related to site fidelity, clear limitations to gene flow between Mexico and Central America locations were observed probably related to oceanic circulation in the area. Design management strategies in countries where the dolphinfish is explored is of primary interest to preserve genetic resources. It is necessary to define the existence of genetic differences of populations for species that are highly dependent on environmental factors limiting its distributional range as is the case of the dolphinfish.

A Magnet‐Driven Soft Bistable Actuator

AbstractBistable morphing structures are widely used as actuation mechanisms in soft actuators, soft robotics, energy absorbers, mechanical computers, optical lenses, metamaterials, and flexible electronics. However, untethered actuators, repetitive actuators, and hybrid‐assembly (containing in‐plane‐assembly and out‐of‐plane‐assembly) actuators remain challenging to realize using existing bistable structures, which hinders the novel application of such actuators in research, engineering, and daily life. This problem is solved by fabricating a magnet‐driven soft bistable actuator (MSBA) unit. The self‐buckling of the circular polydimethylsiloxane (PDMS) sheet ensures the bistability of the actuator and allows it to operate as an independent unit, free of external constraints. The reorientation of neodymium‐iron‐boron (NdFeB) microparticles embedded in the PDMS sheet enables the dome‐shaped actuators to exhibit repetitive snapping under the stimulus of a direction‐switching magnetic field. The potential of this MSBA unit in bionics, electronics, and biomechanics applications is demonstrated in systematic studies involving modification of the buckling deflection and magnetic moment density. The MSBA unit exhibits excellent performance in hybrid designs and intelligent systems.

Madagascar's burned area from Sentinel-2 imagery (2016–2022): Four times higher than from lower resolution sensors

Madagascar is one of the most burned regions in the world, to the point that it has been called the ‘Isle of fire’ or the ‘Burning Island’. An accurate characterization of the burned area (BA) is crucial for understanding the true situation and impacts of fires on this island, where there is an active scientific debate on how fire affects multiple environmental and socioeconomic aspects, and how fire regimes should be in a complex context with differing interests. Despite this, recent advances have revealed that BA in Madagascar is poorly characterised by the currently available global BA products. In this work, we present, validate, and explore a BA database at 20 m spatial resolution for Madagascar covering the period 2016–2022. The database was built based on 75,010 Sentinel-2 images using a two-phase BA detection algorithm. The validation with independent long-term reference units showed Dice coefficients ≥79 %, omission errors ≤24 %, commission errors ≤18 %, and a relative bias ≥ − 8 %. An intercomparison with other available global BA products (GABAM, FireCCI51, C3SBA11, or MCD64) demonstrated that our product (i) exhibits temporal consistency, (ii) represents a significant accuracy improvement, as it reduces BA underestimations by about eightfold, (iii) yields BA estimates four times higher, and (iv) shows enhanced capability in detecting fires of all sizes. The observed BA spatial patterns were heterogeneous across the island, with 32 % of the grasslands burning annually, in contrast to other land cover types such as the dense tropical forest where <2 % burned every year. We conclude that the BA characterization in Madagascar must be addressed using imagery at spatial resolution higher than MODIS or Sentinel-3 (≥250 m), and temporal resolution higher than Landsat (16 days) to deal with cloudiness, the rapid attenuation of burn scars signals, and small fire patches.

Efficient management of HVAC systems through coordinated operation of parallel chiller units: An economic predictive control approach

In developed countries, air conditioning systems have become major contributors to energy consumption in buildings. Cooling installations made up of independent chiller units connected in parallel pose a challenge in finding the most energy-efficient management strategy. This article proposes a novel economic model predictive control strategy to optimize the operation of multiple-chiller HVAC systems according to an economic cost comprising energy consumption as well as a thermal comfort index. Provided that the gradient of the economic cost function can be calculated or estimated, the proposed controller only entails the solution of a single quadratic programming (QP) problem at each sampling period, reducing computational requirements and thus facilitating the deployment on commercial embedded HVAC management platforms. The proposed controller improves economic performance. As our numerical analysis shows, optimal sequencing is achieved for the case of dual-chiller plants. Moreover, the controller adapts to possible variations in the economic criteria, enabling the system to respond to changes in electricity price and user preferences. A realistic case study, using a high fidelity model of a building simulated in TRNSYS, demonstrates the effectiveness of the proposed methodology. In particular, the proposed controller demonstrates to be more efficient than state-of-the-art QP-based economic predictive controllers in achieving a reduction of the energy consumption up to 5.19%, which is in line with the targeted reduction of 7.9% by 2030 in the EU Green Deal's ‘Fit for 55’ package.

Structural and syntactic features of article titles about coronavirus

Over the past few years, articles regarding COVID-19 have remained pertinent in various media outlets, the internet and other communication platforms, which has ultimately resulted in the significance of the coronavirus topic not just in medical research, but also in the linguistic realm. Studying headlines of articles about coronavirus poses a challenge for researchers. The issue arises due to the significant role of journalism in influencing public opinion and the readership. Additionally, modern society's fascination with the coronavirus infection and the pandemic complicates the study further. The importance of this study is due to the newness of the subject matter, with limited coverage in scientific literature. The aim of this article is to examine the structural and semantic characteristics of article headings relating to the coronavirus. To achieve this goal, several tasks need to be accomplished. Firstly, it is necessary to identify and analyse the characteristics of the headline as part of the journalistic text, its various types and functions, and its consistency with the content of the article. Secondly, a study must be conducted on the structural and semantic features of the coronavirus-related article headlines. This includes determining the frequency of usage of different structural patterns of simple and complex sentences in both British and Russian publications, and examining the impact of these patterns on the readers' perception of the article's content. According to the research, it was concluded that the title of a publication serves a dual purpose as an independent unit and an essential component of the text. The title has various functions, including graphic-excretory, informative, nominative, and advertising-expressive. It is characterised by its brevity, nominativeness, and written fixity which contribute to its effectiveness.

Microgels for bioprinting: recent advancements and challenges.

Microgels have become a popular and powerful structural unit in the bioprinting field due to their advanced properties, ranging from the tiny size and well-connected hydrogel (nutrient) network to special rheological properties. Different microgels can be fabricated by a variety of fabrication methods including bulk crushing, auxiliary dripping, multiphase emulsion, and lithography technology. Traditionally, microgels can encapsulate specific cells and are used for in vitro disease models and in vivo organ regeneration. Furthermore, microgels can serve as a drug carrier to realize controlled release of drug molecules. Apart from being used as an independent application unit, recently, these microgels are widely applied as a specific bioink component in 3D bioprinting for in situ tissue repair or building special 3D structures. In this review, we introduce different methods used to generate microgels and the microgel-based bioink for bioprinting. Besides, the further tendency of microgel development in future is introduced and predicted to provide guidance for related researchers in exploring more effective ways to fabricate microgels and more potential bioprinting application cases as multifunctional bioink components.

Study on design and impact energy absorption of Voronoi porous structure with tunable Poisson's ratio

As the inner core of crash box, the porous structure could cushion impact load through its own deformation. The aims of this study were to propose a series of Voronoi porous structures with tunable Poisson's ratio (VP-VPS) by using the periodic array of unit cells based on Voronoi-Tessellation and to develop crash boxes filled with porous structures for strong crashworthiness and high energy absorption. VP-VPS structures through the periodic arrays of unit cells were constructed according to 4 independent unit cell design factors. The quasi-static and dynamic compressive mechanical responses of VP-VPS structures prepared by selective laser melting (SLM) were studied through the combinations of mechanical test and simulation. Relationships between VP-VPS unit cell design factors and mechanical properties of structures were determined by establishing regression equations using the response surface method (RSM). Finally, the energy absorption of new crash boxes filled with VP-VPS structures was investigated through simulation. Results showed that VP-VPS structures had high load-bearing capacities and energy absorption under quasi-static and dynamic compressive conditions. Regression equations based on RSM could well predict mechanical properties of structures. The mechanical properties of VP-VPS structures were enhanced with the increase of global strain rate, which showed different deformation modes at low and high global strain rates. Compared with typical crash boxes filled with negative Poisson's ratio (NPR) inner cores, new type VP-VPS crash boxes had stronger impact resistance and higher energy absorption. This investigation provided a feasible design solution and theoretical basis for the construction and engineering application of impact resistance protective structures.

Palaeomagnetic results from Early Mesozoic strata in the Qaidam Basin and their implications for the formation of the Northern China Domain

SUMMARY The Northern China Domain is located between the Central Asian Orogenic Belts to the north and the Kunlun–Qinling belt to the south, and it comprises the North China, Alxa and Tarim blocks. The relationships among the Northern China domain and the southern tectonic elements such as the Qaidam Basin/Terrane are debated because of the major modification by crustal deformation in the late Mesozoic–Cenozoic. To address this issue, we conducted a palaeomagnetic and high-precision radiometric dating study of Triassic volcanic rocks and Middle Jurassic strata in the Qaidam Terrane. Our objective was to determine the relationship between the Qaidam Terrane with the Tarim Block and the North China Block (NCB) during the late Palaeozoic and early Mesozoic. Four volcanic samples yielded zircon U-Pb ages of 236–243 Ma. The characteristic remanent magnetizations (Middle Triassic: D = 40.2°, I = 54.6°, α95 = 3.4°; Middle Jurassic: D = 27.4°, I = 48.0°, α95 = 7.9°) passed the fold and reversal tests, and yielded Middle Triassic and Middle Jurassic palaeopole positions at 57.6° N, 178.2° E, A95 = 4.0° and 65.8° N, 197.6° E, A95 = 7.8°, respectively. Based on these new poles, combined with other reliable data, we compared the apparent polar wander path (APWP) of the Qaidam Terrane with those of the NCB and Tarim Block. The results show that, from the Carboniferous through Early Cretaceous, the APWP of the Qaidam Terrane resembles that of the Tarim Block, but it is quite different from that of the NCB. Combined with other reported evidence, we conclude that the Qaidam Terrane was an independent dynamic unit during the late Palaeozoic until its connection with the Tarim Block, which was followed by continuous eastward motion. During this process, the connection between the Qaidam Terrane and the NCB–Alxa blocks occurred in the Middle Triassic, and subsequently the Qaidam Terrane underwent multiple tectonic responses to collisions with the Qiangtang Terrane, Lhasa Terrane and the India Plate, before the formation of its modern tectonic configuration.