Large Structures Research Articles

Non-contact Testing of Large Concrete Structures for Voids and Delaminations

Concrete is the most used construction material for civil engineering structures, as it is reliable, cost-efficient, and long lasting. Infrastructure made of reinforced concrete can be used for many decades, provided that maintenance is rigorous. The necessary periodic checks are typically manual tasks, including visual inspection for defects on the outside and hammering to find internal voids and imminent spalling. In this a paper, a non-contact system for automated inspection is presented. Two parallel lasers are used with a scanning head on a mobile platform to cover large areas. The first laser emits a high energy pulse, igniting plasma on the surface and subsequently inducing a shock wave into the structure. The second laser measures the resulting vibration. Signal analysis of individual measurement points give a first indication about the presence of faults. Unsupervised learning and visual computing are used to find and narrow down damaged areas in the scanning data with higher probability. After systematic testing in the laboratory, measurements were conducted recently in two tunnels with concrete linings. This paper provides an overview of the developed hardware and signal analysis techniques. Furthermore, the recent verification results are presented for the first time. In future, the proposed method can be combined with geometric scans and automated optical inspection of the surface to offer a holistic inspection approach and relieve the authorities that are responsible for operation and maintenance of the growing number of aging infrastructures.

Vibration analysis of a partially submerged structure using the DIC technique

The continuous expansion of offshore wind turbine sites has been garnering increasing attention, particularly in countries where available land is limited. Nevertheless, efficiently allocating resources for the maintenance and repair of offshore wind turbines presents a formidable challenge. This challenge is compounded by the complex and often unpredictable weather conditions, as well as various business-related issues specific to the offshore environment. To tackle these challenges, one effective solution is to implement vibration analysis through the use of digital image correlation (DIC) methods. This approach has a well-established theoretic background dating back to approximately 2008 and has demonstrated its effectiveness in the realm of structural health monitoring for large structures like bridges and towers. Relevant information on the upper structure of the wind turbines has been obtained using numerical models in our previous work. Changes in the structural feature frequencies of wind turbines are the primary focus in vibration analysis. However, changes in feature frequencies can occur for various reasons, and relying solely on frequency shifts can make it challenging to pinpoint the precise areas of damage within wind turbine structures, especially without the benefit of long-term observations. In this study, the DIC method is employed on scaled cylindrical models to gain insights into the frequency variations stemming from the erosion of non-cohesive soils beneath offshore wind turbine foundations. Changes in modal curvature within the upper structure of the wind turbine will also be analyzed. This additional investigation will enable a clear differentiation between defects in the upper structure and frequency shifts resulting from erosion or problems with the underwater foundation.

Sideband Peak Count – a new nonlinear ultrasonic technique for monitoring damage progression in engineering materials

Linear ultrasonic (LU) techniques used by majority of the researchers working in material damage monitoring, are reliable for detecting relatively large defects. If the defect dimensions are in the range of the ultrasonic wavelength or larger, then those defects can be detected by analyzing the scattered ultrasonic fields. Material damage affects LU parameters such as ultrasonic wave speed and attenuation and their changes are detectable for relatively large defects. However, for small defects (when defect dimensions are significantly smaller than the wavelength of the propagating signal) the changes in the LU parameters are too small to detect or measure reliably. For detecting small defects engineers often use high frequency ultrasonic signals to make the defect dimensions greater than the wavelength. However, high frequency signals attenuate quickly and therefore, only very small regions near the ultrasonic probe can be inspected in this manner. Inspecting large structures by high frequency ultrasonic signals requires moving the probe mechanically from one point to the next and therefore, can be very time consuming. Nonlinear ultrasonic (NLU) technique on the other hand does not need to satisfy this restricting condition that the wavelength of the signal must be smaller than the defect size. NLU works well when the signal wavelength is much larger than the defect size. Therefore, relatively low frequency signals that can propagate a long distance and monitor a large area of a structure can be used for NLU measurements. Different NLU techniques can be used for detection and monitoring of small damages in a specimen. A relatively new NLU technique called the Sideband Peak Count-Index or SPC-I technique has been developed by the author and his collaborators. SPC-I technique for monitoring different types of materials – composites, metals, concrete, and other cement-based materials has been found to be effective. Along with those success stories of SPC-I the effect of topography and the advantage of topological sensing is also discussed in this presentation.

A fast analysis algorithm for structural vibration modal sensitivity

Vibration modal sensitivity analysis has a wide range of applications in structural optimization design, model correction, fault detection, and reliability analysis. The existing methods for calculating modal sensitivity mainly include modal superposition method, Nelson’s method, and some improved algorithms derived from them. However, the existing algorithms have the drawback of low computational efficiency when applied to modal sensitivity analysis of the large-scale structures. In view of this, the objective of this work is to develop a fast modal sensitivity analysis method that can more efficiently calculate the modal sensitivity of the large structures with thousands of degrees of freedom. This new sensitivity analysis technique integrates Sherman-Morrison-Woodbury formula, subspace iteration and forward-difference to achieve the goal of fast calculation. The innovations of the proposed method mainly include the following aspects. Firstly, the Sherman-Morrison-Woodbury formula is used to quickly calculate the perturbed flexibility matrix due to the minor modification in the structure. Then, the perturbed flexibility matrix is introduced into the subspace iteration method to calculate the perturbed modal parameters. Finally, the forward-difference algorithm is used to calculate the modal sensitivity. Two numerical examples are used to verify the superiority of the proposed modal sensitivity algorithm. Taking the 1952-bar structure as an example, the calculation time of the proposed algorithm is only 8.3 % and 18.2 % of that of the existing approximate modal superposition method and the improved Nelson’s method, respectively. In terms of calculation accuracy, the results obtained by the proposed method are exactly the same as the exact solution when the perturbation scale is set to 10−5. It is found that the proposed method significantly reduces computation time compared to the existing methods on the premise that the calculation accuracy is basically unchanged.

An improved and extended parameterization of the CO2 15 µm cooling in the middle and upper atmosphere (CO2_cool_fort-1.0)

Abstract. The radiative infrared cooling of CO2 in the middle atmosphere, where it emits under non-local thermodynamic equilibrium (non-LTE) conditions, is a crucial contribution to the energy balance of this region and hence to establishing its thermal structure. The non-LTE computation is too CPU time-consuming to be fully incorporated into climate models, and hence it is parameterized. The most used parameterization of the CO2 15 µm cooling for Earth's middle and upper atmosphere was developed by Fomichev et al. (1998). The valid range of this parameterization with respect to CO2 volume mixing ratios (VMRs) is, however, exceeded by the CO2 of several scenarios considered in the Coupled Climate Model Intercomparison Projects, in particular the abrupt-4×CO2 experiment. Therefore, an extension, as well as an update, of that parameterization is both needed and timely. In this work, we present an update of that parameterization that now covers CO2 volume mixing ratios in the lower atmosphere from ∼0.5 to over 10 times the CO2 pre-industrial value of 284 ppmv (i.e. 150 to 3000 ppmv). Furthermore, it is improved by using a more contemporary CO2 line list and the collisional rates that affect the CO2 cooling rates. Overall, its accuracy is improved when tested for the reference temperature profiles as well as for measured temperature fields covering all expected conditions (latitude and season) of the middle atmosphere. The errors obtained for the reference temperature profiles are below 0.5 K d−1 for the present-day and lower CO2 VMRs. Those errors increase to ∼1–2K d−1 at altitudes between 110 and 120 km for CO2 concentrations of 2 to 3 times the pre-industrial values. For very high CO2 concentrations (4 to 10 times the pre-industrial abundances), those errors are below ∼1 K d−1 for most regions and conditions, except at 107–135 km, where the parameterization overestimates them by ∼1.2 %. These errors are comparable to the deviation of the non-LTE cooling rates with respect to LTE at about 70 km and below, but they are negligible (several times smaller) above that altitude. When applied to a large dataset of global (pole to pole and four seasons) temperature profiles measured by MIPAS (Michelson Interferometer for Passive Atmospheric Spectroscopy) (middle- and upper-atmosphere mode), the errors of the parameterization for the mean cooling rate (bias) are generally below 0.5 K d−1, except between 5×10-3 and 3×10-4 hPa (∼85–98 km), where they can reach biases of 1–2 K d−1. For single-temperature profiles, the cooling rate error (estimated by the root mean square – rms – of a statistically significant sample) is about 1–2 K d−1 below 5×10-3 hPa (∼85 km) and above 2×10-4 hPa (∼102 km). In the intermediate region, however, it is between 2 and 7 K d−1. For elevated stratopause events, the parameterization underestimates the mean cooling rates by 3–7 K d−1 (∼10 %) at altitudes of 85–95 km and the individual cooling rates show a significant rms (5–15 K d−1). Further, we have also tested the parameterization for the temperature obtained by a high-resolution version of the Whole Atmosphere Community Climate Model (WACCM-X), which shows a large temperature variability and wave structure in the middle atmosphere. In this case, the mean (bias) error of the parameterization is very small, smaller than 0.5 K d−1 for most atmospheric layers, reaching only maximum values of 2 K d−1 near 5×10-4 hPa (∼ 96 km). The rms has values of 1–2 K d−1 (∼20 %) below ∼2×10-2 hPa (∼80 km) and values smaller than 4 K d−1 (∼2 %) above 10−4 hPa (∼105 km). In the intermediate region between ∼5×10-3 and ∼2×10-4 hPa (85–102 km), the rms is in the range of 5–12 K d−1. While these values are significant in percentage at ∼5×10-3–5×10-4 hPa, they are very small above ∼5×10-4 hPa (96 km). The routine is very fast, taking (1.5–7.5) ×10-5 s, depending on the extension of the atmospheric profile, the processor and the Fortran compiler.

Experimental and statistical study on sound absorption coefficient of porous asphalt concrete considering mesoscopic pore parameters

Porous asphalt concrete (PAC) has attracted significant attention in the road industry due to its excellent noise reduction capabilities. However, clogging in PAC decreases its sound absorption performance, as mesoscopic pore parameters play a crucial role in influencing PAC’s sound absorption abilities. To further investigate the influence of mesoscopic pore parameters on the sound absorption performance of PAC, CT scanning and digital image processing technology were employed. The principal component analysis method was employed to determine the weighting of the influence of mesoscopic pore parameters on the sound absorption coefficient. The correlation between different pore parameters and the sound absorption coefficient of PAC specimens was analyzed. The results showed that the minimum Feret diameter has the most significant effect on the sound absorption performance of PAC, while the concavity and the length-short axis ratio have the least impact. The correlation between mesoscopic pore parameters and sound absorption coefficients was found to be inconsistent before and after clogging. Mesoscopic pore parameters that were positively correlated with sound absorption coefficients before clogging turned negatively correlated after clogging. Connected large pores and smooth regular pore structure enhance the sound absorption performance of PAC, but clogging disrupts this structure, resulting in a decrease in sound absorption performance.

Early‐age cracking due to restraint: Laboratory and field investigations on the predictive capacity of the simplified method in Annex D of the future EC2

AbstractThe Annex D of the future EC2 draft gives guidance on the evaluation of early‐age cracking of large structures due to restraint. In case of restrained conditions, compressive stresses are firstly generated in massive structures due to temperature increase, then tensile stresses are generated due to temperature decrease and shrinkage. Due to these tensile stresses, there is a risk of cracking which may be evaluated by the simplified method in Annex D. This method is currently verified against laboratory tests performed in the temperature‐stress testing machine and field cases on restrained concrete elements. The laboratory verification consisted of five approaches to consider different available input (modeled, assumed, or measured). The field investigation focused on the relation between the calculated cracking risk and the observed damage. The results show that the method has very good accuracy and captures with reasonable simplicity the mechanisms and the relations between the parameters involved.

PBF-LB of large-area magnesium WE43 structures surface-enhanced by plasma electrolytic oxidation

AbstractDue to the improved understanding of the industry, additive manufacturing processes are becoming increasingly accepted for fabricating complex lightweight components. The focus of the magnesium research is primarily on small implant structures. Due to challenges in the manufacturing process and oxidation behavior, large structures for lightweight components are mainly fabricated with titanium. This paper expands the scope of the laser-based powder bed fusion (PBF-LB) of larger-area magnesium parts with surface enhancement using the Ultraceramic® by the plasma electrolytic oxidation (PEO). For this purpose, the PBF-LB process development for cylindric structures with a diameter of 31 mm is carried out. The processing strategies are adapted for a crack and porosity free process. To mitigate the inherent oxidation of the biodegradable WE43 and reduce the surface wear in tribologically challenging applications, the additively manufactured magnesium is modified by the Ultraceramic®. The thickness of the ceramic surface could be tailored between 10 and 40 µm, while enclosing adhering powder particles of the PBF. Electrochemical impedance spectroscopy showed an increased resistance to corrosion by an increased modulus |Z0.01| by a factor of 658. The tribological behavior was characterized in pin-on-disc experiments and showed a decrease of surface wear down to 7.9 × 10–6 mm3/N·m up to a Hertzian pressure of 720 MPa tested by a tungsten carbide ball. Therefore, the synthesis of the PBF-LB of large-area magnesium parts and the PEO of the Ultraceramic® enables lightweight components for challenging oxidative and tribological conditions in real world applications.

Influence of polyethylene glycol and various carboxylic acids on the physical and mechanical properties of beech wood (Fagus sylvatica) and Scots pine wood (Pinus sylvestris)

ABSTRACT The goal of this study was to investigate the influence on physical and mechanical properties of beech wood (Fagus sylvatica) and Scots pine wood (Pinus sylvestris) modified with polyethylene glycol (PEG) 400 as an alcohol and various carboxylic acids (citric acid, malic acid and 1,2,3,4-butanetetracarboxylic acid). PEG 400, chosen for its large and flexible structure, was expected to minimize the negative effects on mechanical properties. However, contrary to expectations, tensile and impact bending strength decreased – similar to other modifications. Tensile strength decreased (beech: 36.0% to 46.3%), while the modulus of rupture did not show a strong decrease (beech: 2.4% to 15.2%). The modulus of elasticity (beech: 1.6% to 14.7%), compression strength (beech: 11.7% to 40.6%) and hardness (beech: 6.0% to 17.1%) increased. Impact bending strength was reduced (beech: 43.0% to 69.3%). Modifying agents, fixed inside the wood, demonstrated high anti-swelling efficiency during leaching cycles (beech: 27.1% to 45.9%). Equilibrium moisture content was reduced between 20.8% and 39.1% for beech at a relative humidity of 65%.

MoLPC2: Improved prediction of large protein complex structures and stoichiometry using monte carlo tree search and AlphaFold2.

Today, the prediction of structures of large protein complexes solely from their sequence information requires prior knowledge of the stoichiometry of the complex. To address this challenge, we have enhanced the Monte Carlo Tree Search algorithms in MoLPC to enable the assembly of protein complexes while simultaneously predicting their stoichiometry. In MoLPC2, we have improved the predictions by allowing sampling alternative AlphaFold predictions. Using MoLPC2, we accurately predicted the structures of 50 out of 175 non-redundant protein complexes (TM-score > = 0.8) without knowing the stoichiometry. MoLPC2 provides new opportunities for predicting protein complex structures without stoichiometry information. MoLPC2 is freely available at https://github.com/hychim/molpc2. A notebook is also available from the repository for easy use. Supplementary data are available at Bioinformatics online.

Techniques of creating in-plane fiber waviness in composites and its mechanical performance – A Review

Abstract In-plane fiber waviness is a common manufacturing flaw in composites, which can be observed during the production of items such as wind turbine blades, industrial components, aircraft structures, and automobile parts, etc. When manufacturing large composite structures, the traditional hand lay-up with fabric is labor-intensive and comes with several other issues, leading to various defects. One major but often overlooked defect is in-plane fiber waviness. The current investigation provides an overview of creating several techniques of in-plane fiber waviness faults in composites. Previously, numerous techniques were reported by researchers, employed to induce in-plane fiber waviness with specific parameters for their investigations. An effort has been made to highlight the various non-destructive techniques used for characterizing in-plane fiber waviness. Additionally, this paper presents a compilation of data on the impact of in-plane fiber waviness on the mechanical performance of composites. The paper concludes by proposing scope for additional research in the area of in-plane fiber waviness. Further, a novel method was proposed for creating in-plane fiber waviness which can reduce the possible fiber rotation using semi-circular wooden bars along with clamping arrangements instead of circular bars in the earlier investigations. Consequently, this could be a significant approach which resembles with realistic in-plane waviness generated while producing fiber reinforced polymer (FRP) composite components.

MinActionPath2: path generation between different conformations of large macromolecular assemblies by action minimization.

Recent progress in solving macromolecular structures and assemblies by cryogenic electron microscopy techniques enables sampling of their conformations in different states that are relevant to their biological function. Knowing the transition path between these conformations would provide new avenues for drug discovery. While the experimental study of transition paths is intrinsically difficult, in-silico methods can be used to generate an initial guess for those paths. The Elastic Network Model (ENM), along with a coarse-grained representation (CG) of the structures are among the most popular models to explore such possible paths. Here we propose an update to our software platform MinActionPath that generates non-linear transition paths based on ENM and CG models, using action minimization to solve the equations of motion. The new website enables the study of large structures such as ribosomes or entire virus envelopes. It provides direct visualization of the trajectories along with quantitative analyses of their behaviors at http://dynstr.pasteur.fr/servers/minactionpath/ minactionpath2_submission.

Advancing a Non-Contact Structural and Prognostic Health Assessment of Large Critical Structures

Advancing a Non-Contact Structural and Prognostic Health Assessment of Large Critical Structures

Biodiversity loss reduces global terrestrial carbon storage.

Natural ecosystems store large amounts of carbon globally, as organisms absorb carbon from the atmosphere to build large, long-lasting, or slow-decaying structures such as tree bark or root systems. An ecosystem's carbon sequestration potential is tightly linked to its biological diversity. Yet when considering future projections, many carbon sequestration models fail to account for the role biodiversity plays in carbon storage. Here, we assess the consequences of plant biodiversity loss for carbon storage under multiple climate and land-use change scenarios. We link a macroecological model projecting changes in vascular plant richness under different scenarios with empirical data on relationships between biodiversity and biomass. We find that biodiversity declines from climate and land use change could lead to a global loss of between 7.44-103.14 PgC (global sustainability scenario) and 10.87-145.95 PgC (fossil-fueled development scenario). This indicates a self-reinforcing feedback loop, where higher levels of climate change lead to greater biodiversity loss, which in turn leads to greater carbon emissions and ultimately more climate change. Conversely, biodiversity conservation and restoration can help achieve climate change mitigation goals.

Insights into the writing process of the mask-free nanoprinting fluid force microscopy technology

Platelets are activated immediately when contacting with non-physiological surfaces. Minimization of surface-induced platelet activation is important not only for platelet storage but also for other blood-contacting devices and implants. Chemical surface modification tunes the response of cells to contacting surfaces, but it requires a long process involving many regulatory challenges to transfer into a marketable product. Biophysical modification overcomes these limitations by modifying only the surface topography of already approved materials. The available large and random structures on platelet storage bags do not cause a significant impact on platelets because of their smallest size (only 1–3 μm) compared to other cells. We have recently demonstrated the feasibility of the mask-free nanoprint fluid force microscope (FluidFM) technology for writing dot-grid and hexanol structures. Here, we demonstrated that the technique allows the fabrication of nanostructures of varying features including grid, circle, triangle, and Pacman-like structures. Characteristics of nanostructures including height, width, and cross-line were analyzed and compared using atomic force microscopy imaging. Based on the results, we identified several technical issues, such as the printing direction and shape of structures that directly altered nanofeatures during printing. Importantly, both geometry and interspace governed the degree of platelet adhesion, especially, the structures with triangular shapes and small interspaces prevent platelet adhesion better than others. We confirmed that FluidFM is a powerful technique to precisely fabricate a variety of desired nanostructures for the development of platelet/blood-contacting devices if technical issues during printing are well controlled.

Bioinformatic prediction of proteins relevant to functions of the bacterial OLE ribonucleoprotein complex.

OLE (ornate, large, extremophilic) RNAs are members of a noncoding RNA class present in many Gram-positive, extremophilic bacteria. The large size, complex structure, and extensive sequence conservation of OLE RNAs are characteristics consistent with the hypothesis that they likely function as ribozymes. The OLE RNA representative from Halalkalibacterium halodurans is known to localize to the phospholipid membrane and requires at least three essential protein partners: OapA, OapB, and OapC. However, the precise biochemical functions of this unusual ribonucleoprotein (RNP) complex remain unknown. Genetic disruption of OLE RNA or its partners revealed that the complex is beneficial under diverse stress conditions. To search for additional links between OLE RNA and other cellular components, we used phylogenetic profiling to identify proteins that are either correlated or anticorrelated with the presence of OLE RNA in various bacterial species. This analysis revealed strong correlations between the essential protein-binding partners of OLE RNA and organisms that carry the ole gene. Similarly, proteins involved in sporulation are correlated, suggesting a potential role for the OLE RNP complex in spore formation. Intriguingly, the Mg2+ transporter MpfA is strongly anticorrelated with OLE RNA. Evidence indicates that MpfA is structurally related to OapA and therefore MpfA may serve as a functional replacement for some contributions otherwise performed by the OLE RNP complex in species that lack this device. Indeed, OLE RNAs might represent an ancient RNA class that enabled primitive organisms to sense and respond to major cellular stresses.IMPORTANCEOLE (ornate, large, extremophilic) RNAs were first reported nearly 20 years ago, and they represent one of the largest and most intricately folded noncoding RNA classes whose biochemical function remains to be established. Other RNAs with similar size, structural complexity, and extent of sequence conservation have proven to catalyze chemical transformations. Therefore, we speculate that OLE RNAs likewise operate as ribozymes and that they might catalyze a fundamental reaction that has persisted since the RNA World era-a time before the emergence of proteins in evolution. To seek additional clues regarding the function of OLE RNA, we undertook a computational effort to identify potential protein components of the OLE ribonucleoprotein (RNP) complex or other proteins that have functional links to this device. This analysis revealed known protein partners and several additional proteins that might be physically or functionally linked to the OLE RNP complex. Finally, we identified a Mg2+ transporter protein, MpfA, that strongly anticorrelates with the OLE RNP complex. This latter result suggests that MpfA might perform at least some functions that are like those carried out by the OLE RNP complex.

Design on thermal-mechanism coordination for binding reinforcing mesh based on shape memory polymer

Abstract The traditional rebar binding devices require complex drive and transmission mechanisms, which leads to large volume and complex structure. In this paper, a cylindrical thermoplastic shape memory polymer (SMP) fixture is proposed to verify the rebar binding method of thermal-mechanism coordination. The SMP fixture is manufactured by the injection molding technology through selecting suitable-ratio Polylactic acid (PLA) and Polycaprolactone (PCL) blend materials. Besides, an additional auxiliary device is presented to overcome the incomplete recovery disadvantage existing in the thermoplastic SMP and completely achieve binding the rebar. On this base, two different binding methods are proposed to compare the mechanical performance after fixing the rebar, and the external force/thermal contributions are tested and discussed in detail. The tested results show that the binding contribution of heat could reach 70% while the binding contribution of external force could reach 30% above the transition temperature (Tg). The maximum tensile force that the binding rebar can withstand under the thermal-mechanism coordination action could reach up to 657.7 N, which is higher than the maximum tensile force of the wire binding. In addition, the maximum friction force between rebar and notches of fixture could reach up to 94.1 N, which further verifies the feasibility of thermal-mechanism coordination for binding reinforcing mesh based on SMP fixture.

Right coronary artery obstruction following transcatheter aortic valve replacement by aortic valve mass.

A 93-year-old woman with symptomatic severe aortic stenosis and normal biventricular function was referred for transcatheter aortic valve replacement (TAVR) evaluation. Cardiac computed tomography revealed safe coronary heights and multiple large calcified mobile mass-like structures attached to the aortic valve (AV), confirmed also by transesophageal echocardiography, which were thought to be prominent Lambl's excrescences.

Two halogenated coplanar Schiff base complexes: Insights into the impact of halogen substitution on intermolecular interactions via theoretical calculations

The manipulation of intermolecular interaction intensities significantly influences a wide range of domains in material science, attracting widespread attention from researchers. In this study, we used a strategy distinct from the adjustment of molecular skeletons, through the introduction of different halogenated ligands, two new coplanar halogenated Schiff base complexes with large conjugate structure [CuII(3,5-Cl-Salphmen)]·DMF(CuL3,5-Cl) and [CuII(3Br-5Cl-Salphmen)]·DMF(CuL3Br5Cl), where 3,5-Cl-Salphmen(H2L3,5-Cl) = N,N′-bis(3,5-dichlorosalicylidene)- diamine, 3Br-5Cl-Salphmen(H2L3,5-Br) = N,N′-bis(3‑bromo-5-chlorosalicylidene)- diamine were obtained. The effects of different substituted atoms on molecular orbitals, energy levels, intermolecular interstrength are analyzed in detail by DFT theory calculations, and compared with CuII-3,5-Br-Salphmen(CuL3,5-Br) and non-halogenated analogues CuII-Salphmen(CuLH). Analysis results show that the strategy of increasing molecular conjugation by the substitution of different halogen atoms can not only effectively modulate the charge distribution on the benzene ring but also can precisely control the binding energy as well as strength of intermolecular interactions.

Unveiling Dark Forces with Measurements of the Large Scale Structure of the Universe

Unveiling Dark Forces with Measurements of the Large Scale Structure of the Universe