Outer Shell Research Articles

Stiffening of double-shelled fullerene molecules under uniaxial strains

Onion-like fullerenes (OLFs) have spherical and tunable shell structures that make them perfect solid lubricants, but their molecular mechanical properties are largely unknown as they are extremely difficult to measure. In this computational study, double-shelled OLFs C60@C180, C80@C180, C60@C240 and C80@C240 are subject to uniaxial elastic strains to obtain their mechanical response. Compressive and tensile elastic moduli are calculated using density functional theory with van der Waals correction. We found that the tensile elastic moduli of the single- and double-shelled fullerenes are always larger than the compressive ones by about 50% to 100%. Inserting C80 into C180 causes an increase in compressive elastic modulus from 96.8 GPa to 178.6 GPa, while inserting C60 into C240 cause much smaller increases. The key factor that determines the stiffening effects is the relative sizes of the inner and outer shells.

Stability and programmed sequential release of Lactobacillus plantarum and curcumin encapsulated in bilayer-stabilized W1/O/W2 double emulsion: Effect of pectin as protective shell

In order to overcome the problem that traditional W1/O/W2 double emulsions do not have targeted release performance, thereby better meeting the health needs of consumers, ovalbumin fibrils/pectin-based bilayer-stabilized double emulsion (OP-BDE) co-encapsulated with Lactobacillus plantarum and curcumin was constructed with pectin as the outer protective shell, which was expected to be used in the development of novel functional foods. The effects of pectin coating on the viability of Lactobacillus plantarum under conditions including storage, pasteurization, freeze–thaw cycles and in vitro simulated digestion were investigated. Results showed that pectin as protective shell could significantly enhance the tolerance of Lactobacillus plantarum to various environmental factors. Besides, the adsorption of pectin endowed OP-BDE with higher lipolysis and stronger protective effect on curcumin, remarkably improving the photostability and bioaccessibility of curcumin. In addition, in vitro simulated gastrointestinal release study indicated that OP-BDE possessed programmed sequential release property, allowing curcumin and Lactobacillus plantarum to be released in small intestine and colon, respectively. OP-BDE is the first reported co-delivery emulsion system with programmed release characteristic. This study provides new insights into OP-BDE in constructing co-delivery systems and programmed sequential release of active substances, and has potential reference and application value in actual food production.

Heterostructural NiFeW disulfide and hydroxide dual‐trimetallic core‐shell nanosheets for synergistically effective water oxidation

AbstractA stable and highly active core‐shell heterostructure electrocatalyst is essential for catalyzing oxygen evolution reaction (OER). Here, a dual‐trimetallic core‐shell heterostructure OER electrocatalyst that consists of a NiFeWS2 inner core and an amorphous NiFeW(OH)z outer shell is designed and synthesized using in situ electrochemical tuning. The electrochemical measurements of different as‐synthesized catalysts with a similar mass loading suggest that the core‐shell Ni0.66Fe0.17W0.17S2@amorphous NiFeW(OH)z nanosheets exhibit the highest overall performance compared with that of other bimetallic reference catalysts for the OER. Additionally, the nanosheet arrays were in situ grown on hydrophilic‐treated carbon paper to fabricate an integrated three‐dimensional electrode that affords a current density of 10 mA cm−2 at a small overpotential of 182 mV and a low Tafel slope of 35 mV decade−1 in basic media. The Faradaic efficiency of core‐shell Ni0.66Fe0.17W0.17S2@amorphous NiFeW(OH)z is as high as 99.5% for OER. The scanning electron microscope, transmission electron microscope, and X‐ray photoelectron spectroscopy analyses confirm that this electrode has excellent stability in morphology and elementary composition after long‐term electrochemical measurements. Importantly, density functional theory calculations further indicate that the core‐shell heterojunction increased the conductivity of the catalyst, optimized the adsorption energy of the OER intermediates, and improved the OER activity. This study provides a universal strategy for designing more active core‐shell structure electrocatalysts based on the rule of coordinated regulation between electronic transport and active sites.

Cryo-EM structures of Banna virus in multiple states reveal stepwise detachment of viral spikes

Banna virus (BAV) is the prototype Seadornavirus, a class of reoviruses for which there has been little structural study. Here, we report atomic cryo-EM structures of three states of BAV virions—surrounded by 120 spikes (full virions), 60 spikes (partial virions), or no spikes (cores). BAV cores are double-layered particles similar to the cores of other non-turreted reoviruses, except for an additional protein component in the outer capsid shell, VP10. VP10 was identified to be a cementing protein that plays a pivotal role in the assembly of BAV virions by directly interacting with VP2 (inner capsid), VP8 (outer capsid), and VP4 (spike). Viral spikes (VP4/VP9 heterohexamers) are situated on top of VP10 molecules in full or partial virions. Asymmetrical electrostatic interactions between VP10 monomers and VP4 trimers are disrupted by high pH treatment, which is thus a simple way to produce BAV cores. Low pH treatment of BAV virions removes only the flexible receptor binding protein VP9 and triggers significant conformational changes in the membrane penetration protein VP4. BAV virions adopt distinct spatial organization of their surface proteins compared with other well-studied reoviruses, suggesting that BAV may have a unique mechanism of penetration of cellular endomembranes.

Study of the Failure Mechanism of a High-Density Polyethylene Liner in a Type IV High-Pressure Storage Tank.

The use of Type IV cylinders for gas storage is becoming more widespread in various sectors, especially in transportation, owing to the lightweight nature of this type of cylinder, which is composed of a polymeric liner that exerts a barrier effect and an outer composite material shell that primarily imparts mechanical strength. In this work, the failure analysis of an HDPE liner in a Type IV cylinder for high-pressure storage was carried out. The breakdown occurred during a cyclic pressure test at room temperature and manifested in the hemispherical head area, as cracks perpendicular to the liner pinch-off line. The failed sample was thoroughly investigated and its characteristics were compared with those of other liners at different stages of production of a Type IV cylinder (blow molding, curing of the composite material). An examination of the liner showed that no significant chemical and morphological changes occurred during the production cycle of a Type IV cylinder that could justify the liner rupture, and that the most likely cause of failure was a design-related fatigue phenomenon.

Preparation and crystallization behavior of sensitive thermochromic microencapsulated phase change materials

A novel sensitive thermo-chromic microcapsules with inorganic/organic nanoparticles-embedded composite shell was designed and synthesized, and the thermal properties, thermo-chromic performance, crystallization behavior of ethyl myristate (EM) in confined spaces were studied in this paper. As the reaction proceeded, the aminated silica (NH2-SiO2) nanoparticles modified outer shell in the aqueous phase and isophorone diisocyanate (IPDI) in the oil phase gradually self-assembled at the inner interface, leading to the formation of an inorganic/organic polymers composite shell. The effect of NH2-SiO2 nanoparticles content on the crystallization behavior, microstructure, morphology, and phase-change properties as well as the thermal stability of MPCMs were investigated in detail. Interestingly, the covalent attachment of NH2-SiO2 nanoparticles on the capsules surface offered long-term chemical stability compared to that of conventional physical adsorption. The NH2-SiO2 nanoparticles were found distributed uniformly on the surface of MPCMs, and the onset crystallization temperature of MPCMs increased by 7.3 °C with NH2-SiO2 nanoparticles addition of 15% content, which counteracts the super-cooling phenomenon. Microcapsule temperature change optical microscopy and non-isothermal crystallization kinetics revealed that the crystallization of RS-MPCMs were homogeneous as well. RS-MPCMs have significant potential in green energy applications due to their latent heat storage, thermal stability, thermal conductivity, leakage prevention, and mechanical properties.

Missed foreign body falsely interpreted as glass in surgery

Retained Foreign Bodies (FBs) in soft tissues are typically a complication of open wounds from trauma, accidents, and surgery, for which plenty of patients seek acute medical care. The importance of localizing these FBs is vital to patient health because it reduces the detrimental complications of loss of function, local tissue damage, infection, and sepsis. In today’s modern age, many automobile taillights are composed of three components: the polycarbonate outer shell, the light bulb, and various metal casings. Occasionally, patients present with one of these objects retained in their body. Here, we present the case of a FB that was dictated as a hematoma; however, it was a piece of polycarbonate that was reported as a piece of glass in the operating room transcript. Based upon imaging a piece of taillight polycarbonate at our institution, the Hounsfield Units (HU) averaged to be 88.62. Nonetheless, if there is acute blood in soft tissues, taillight plastic could be an appropriate differential; however, a hematoma is less likely to be polycarbonate from car rear lights based on the HU.

Simultaneously enhancing strength and ductility of coarse grain Cu–Al alloy via a macro dual-cable structure

The trade-off relationship of strength and ductility of metals leads to a strength increase accompanied by a ductility decrease. In the past two decades, despite significant efforts to increase strength while minimizing the ductility loss by tailoring microstructures, it has been rare to achieve simultaneous enhancement in strength and ductility, i.e., to disrupt the trade-off relationship. Here via rotary swaging and subsequent annealing, we prepared a macro dual-cable structured Cu–Al alloy rod with an inner micro-grain (MG) core (2.2 mm in diameter, 54% volume fraction) wrapped in an outer ultrafine-grain (UFG) shell (a thickness of 0.4 mm). Tensile tests revealed that the inner core has a yield strength of 472 MPa and a ductility of 29.1%, while the wrapping of the outer shell simultaneously enhances the yield strength to 552 MPa and ductility to 31.9%, respectively. The analysis of strain during the stretching process shows that the shell has a strong restraining effect on the core. Microstructure characterization indicates that the core blocks the propagation of the shear bands of shell and maximizes its density. At the same time, the restriction of the shell increases the lattice defect accumulation and work hardening ability as well as ductility of the core. Our research not only provides a method for preparing macro dual-cable structured materials with industrial scale and clean interface, but also explores a new strategy for simultaneously enhancing strength and ductility of metals, which designs macro millimeter-scale structures instead of adjusting microstructure from the micrometer scale.

Vibration transmission analyses of double-layer cylindrical shell with fully immersed elastic connections through experimental and analytical approaches

This paper investigates vibration transmission characteristics of the double-layer cylindrical shell with fully immersed elastic connections through experimental and analytical approaches. A test sample of the double-layer cylindrical shell connected by six vibration isolators is firstly manufactured and a forced vibration test is done with fully immersed interlayer. Meanwhile, a novel analytical approach is developed to calculate vibration responses of an unequal double-layer cylindrical shell with fully immersed elastic connections. The substructure receptance method and wave propagation method are combined in the coupling theoretical model. Springs are utilized to simulate elastic connections, that are considered as substructures. By comparing the achieved analytical and experimental vibration responses, good agreements are gained and the two approaches are demonstrated. Then the transmission characteristics are gradually analyzed with respect to the double-layer shell with elastic connections, double-layer shell with interlayer fluid and double-layer shell with fully immersed elastic connections. It is found that the interlayer water between the inner and outer shells plays a “short-circuit” role in vibration transmission, which greatly reduces the isolation performance of vibration isolators. Nevertheless, the fully immersed isolators with small stiffness still have the non-ignorable vibration isolation effect compared with the case of rigid connection.

Eggshell microstructure, shell quality indices, mineralogy, and UV–Vis absorbance of domestic eggs of Iran

The structure and quality of eggshells (ES) vary around a mean value depending on different items, and these variations are important in their many industrial and technological applications as will be mentioned (vide infra). Five commercial egg brands of different laying hens are examined and their quality indices, morphological microstructure, elemental composition, and light absorbance at 200–700 nm UV/Vis spectra were compared. The ES layers include a limiting membrane, inner and outer shell membranes, a mammillary layer, a palisade layer, a surface vertical crystal layer, and a bilayer cuticle. The elemental composition of each layer reflects the proteinous or calcified nature of the layers, and various elements, C, O, N, Ca, Fe, Mg, Mn, Pb, Sr, Sc, Hf, Co, and La, were found. The weight difference between egg brands was significant, as well as the difference in ES percentage between white and colored eggs. ES weight possessed a positive relationship with the thickness of the calcified layer. So, the ES is heavier and the egg is larger and heavier when the calcified layer is thicker. The calculated average ES index was 7.99% ± 0.16 SE. In all ES samples, the absorbance in UV wavelength spectra (300–350 nm) was slightly higher than in Vis spectra (400 - 700 nm) and their difference was significant. The difference in absorbance of various treatments was significant and mean absorbance was the highest in the after-furnace (ash) samples and was the lowest for acid-treated ones. It seems that turning the ES into ash can improve the absorbance capability, especially in white ESs.

In situ injectable hydrogel encapsulating Mn/NO-based immune nano-activator for prevention of postoperative tumor recurrence

Postoperative tumor recurrence remains a predominant cause of treatment failure. In this study, we developed an in situ injectable hydrogel, termed MPB-NO@DOX + ATRA gel, which was locally formed within the tumor resection cavity. The MPB-NO@DOX + ATRA gel was fabricated by mixing a thrombin solution, a fibrinogen solution containing all-trans retinoic acid (ATRA), and a Mn/NO-based immune nano-activator termed MPB-NO@DOX. ATRA promoted the differentiation of cancer stem cells, inhibited cancer cell migration, and affected the polarization of tumor-associated macrophages. The outer MnO2 shell disintegrated due to its reaction with glutathione and hydrogen peroxide in the cytoplasm to release Mn2+ and produce O2, resulting in the release of doxorubicin (DOX). The released DOX entered the nucleus and destroyed DNA, and the fragmented DNA cooperated with Mn2+ to activate the cGAS-STING pathway and stimulate an anti-tumor immune response. In addition, when MPB-NO@DOX was exposed to 808 nm laser irradiation, the Fe-NO bond was broken to release NO, which downregulated the expression of PD-L1 on the surface of tumor cells and reversed the immunosuppressive tumor microenvironment. In conclusion, the MPB-NO@DOX + ATRA gel exhibited excellent anti-tumor efficacy. The results of this study demonstrated the great potential of in situ injectable hydrogels in preventing postoperative tumor recurrence.

Carbon fibers coated with floral MoSe2 are applied to high-performance electromagnetic absorbing materials

Studied the microwave absorption performance of carbon fiber, mixed carbon fiber/MoSe2 (CM) bilayer composite materials in the range of 2–18 GHz. The flower-shaped layer and core-shell double-layer interface of MoSe2 work together to improve electromagnetic wave absorption, providing a new approach for designing lightweight, broadband, and strong absorption-absorbing materials. To address the drawbacks of the high conductivity of pure carbon fibers, transition metal sulfides were introduced promptly, and the CM core-shell materials with flower-shaped outer shell structures were prepared. An in-depth analysis of the working mechanism of CM absorbing materials and the influence of the interface between carbon fibers and MoSe2 on the absorbing performance has been conducted, providing a favorable experimental basis for the application of fiber membranes in absorbing materials.

METHODOLOGY FOR PREDICTING THE MATERIALS ELASTIC MODULUS OF PRODUCTS PRODUCED BY LAYER-BY-LAYER CLADDING WORKING UNDER THREE-POINT BENDING CONDITIONS

The work is devoted to the investigation of the influence of technological filling density on the distribution of elastic modulus when printing functional parts by the layer-by-layer deposition modeling (FDM) method in terms of stiffness under three-point bending conditions, in an elastic isotropic setting. The structure of the product is considered as a set of the body of the outer shell formed during printing by the outer perimeters and the inner body, which is directly the technological filling. The data of experimental studies of elasticity modulus distribution for both the outer shell and the inner structure are given, the nomogram of elasticity modulus distribution is obtained, allowing in general to estimate the functionality of the part in the aspect of providing the required elasticity modulus in calculations.

Is the Local Energy Conservation Law Valid inside the Electronic Device of Charged Capacitors?

The energy conservation is one of the most fundamental and well established principles in physics. Emmy Noether extended the energy conservation principle to the quantum field theoretical domain in empty space by relating the time translation invariance of the universe with energy conservation. While this is the case in open empty space, it seems that the local space enclosed by conducting metallic plates has unexpected property suggesting that the energy conservation principle does not necessarily apply to localized bound system of capacitors in electrodynamics. This point of view was raised by noticing the fact that the spherical capacitor has calculable electrostatic self-potential energy in both the inner and outer shells respectively which was not taken into account in the conventional consideration of the total energy stored in the capacitors. It seems like the concept of moving charges one by one into the capacitor plates has blindsided the investigators to bypass the necessary steps to account for the additional repulsive self-potential energy that accumulates simultaneously in both of the capacitor plates in the process of charging the capacitor. The investigation shows that the repulsive self-potential energies from both of the capacitor plates have indeed been omitted in the conventional calculation of the stored energy in the capacitors. We present the dynamics of the stored potential energy in capacitors and discuss its physical consequences in relation to the anomalous energy devices reported in the past.

Spherical geometry convection in a fluid with an Arrhenius thermal viscosity dependence: The impact of core size and surface temperature on the scaling of stagnant-lid thickness and internal temperature

The rock and rock-ice mixtures of the core-enveloping spherical shells comprising terrestrial body interiors have thermally determined viscosities well described by an Arrhenius dependence. Accordingly, the implied viscosity contrasts determined from the activation energies (E) characterizing such bodies can reach values exceeding 1040, for a temperature range that spans the conditions found from the lower mantle to the surface. In this study, we first explore the impact of implementing a cut-off to limit viscosity magnitude in cold regions. Using a spherical annulus geometry, we investigate the influence of core radius, surface temperature, and convective vigour on stagnant lid formation resulting from the extreme thermally induced viscosity contrasts. We demonstrate that the cut-off viscosity must be increased with decreasing curvature factor, f (=rin/rout, where rin and rout are the inner and outer radii of the annulus, respectively), if the solutions are to be not only computationally manageable but physically valid. We find that for statistically-steady systems, the mean temperature decreases with core size, and that a viscosity contrast of at least 107 is required for stagnant lid formation as f decreases below 0.5. Inverting the results from over 80 calculations featuring stagnant lids (from a total of approximately 180 calculations), we apply an energy balance model for heat flow across the thermal boundary layers and find that the non-dimensionalized temperature in the Approximately Isothermal Layer (AIL) in the convecting region under a stagnant lid is well predicted by TAIL′=12−2Tout′+γ+γ2+4γ1+Tout′ where γ is a function of E and f, and Tout′ is the non-dimensionalized surface temperature. Moreover, the normalized (i.e., non-dimensional) thickness of the stagnant lid, L′, can be obtained from a measurement of the non-dimensional surface heat flux once TAIL′ is determined. Stagnant-lid thicknesses increase from 10 to 30% of the shell thickness as f is decreased, and thick lids can overlie vigorously convecting underlying layers in small core bodies, potentially delaying secular cooling and suggesting that small objects with small cores may have developed thick elastic outer shells early in the solar system's history while maintaining vigorously convecting interiors. However, we also find that for the small number of 3-D calculations that we examined, parametrizations based on 2-D calculations overestimate the temperature of the convecting layer and the thickness of the conductive lid when f is small (less than 0.4).

Experimental methods in chemical engineering: X‐ray fluorescence—XRF

AbstractX‐ray fluorescence (XRF) is a non‐destructive spectrometric technique to detect elements with an atomic number from 11 (sodium) and beyond 92 (uranium). When X‐rays or gamma rays eject tightly bound inner core electrons, an electron from an outer shell will fill the empty orbital and fluoresce. Every element has a characteristic fluorescence, which depends on the element and the electrons in the orbitals that are ejected and those that fill the orbital. With the characteristic energy of the fluorescence, we determine elemental composition and concentration when adequately calibrated. Typical run times range from a second to a few minutes with an sensitivity to as low as (ppm). XRF guns are portable devices that produce qualitative data while libraries loaded to laboratory instruments are capable of producing quantitative data. A broad range of scientists and engineers apply XRF in research—140 of the 250 scientific categories in the Web of Science (WoS) cite XRF analyses. Of the 10,000 articles indexed in WoS since 2018, chemical engineering ranks fifth with the most articles. The focus of the research in this category includes adsorption and waste water, combustion and pyrolysis, catalysis and zeolites, and nanoparticles and oxidation.

X-rays, electrons, and neutrons as probes of atomic matter

X-rays, electrons, and neutrons probe different properties of matter. X-rays feel electron density (ED). Electrons sense the electrostatic potential (ESP) of electrons and nuclei. Neutrons are sensitive to nuclear coherent scattering length (NCSL). While NCSL maps are widely understood to be different, ED and ESP maps are tacitly assumed to be similar. Here, I show that the belief in ED and ESP map equivalence is mistaken, but contains a grain of truth. Using density functional theory (DFT), the Bethe-Mott (BM) relation, and the Thomas-Fermi (TF) and Cromer-Mann (CM) atomic models, I show that ED and ESP maps are indeed more similar to each other than to NCSL maps. Nevertheless, peak and integrated map values depend differently on the atomic order number and on the contributions from electrons in the inner and outer CM shells. ED and ESP maps also differ in the sign and relative magnitude of excess charge effects.

Reducing the Cost of 3D Metal Printing Using Selective Laser Melting (SLM) Technology in the Manufacture of a Drill Body by Reinforcing Thin-Walled Shell Forms with Metal-Polymers

This article describes the technology for manufacturing a metal composite structure of a metal-cutting tool body. The main problem with using metal 3D-printing is its prohibitively high cost. The initial data for carrying out finite element calculations are presented, in particular, the calculation and justification of the selected loads on the drill body arising from metal-cutting forces. The described methodology for designing a digital model of a metal-cutting tool for the purpose of its further production using SLM 3D metal printing methods facilitates the procurement of a digital model characterized by a reduced weight and volume of material. The described design technology involves the production of a thin-walled outer shell that forms the external technological surfaces necessary for the drill body, as well as internal structural elements formed as a result of topological optimization of the product shape. Much attention in this article is paid to the description of the technology for filling internal cavities with a viscous metal polymer, formed as a result of the topological optimization of the original model. Due to this design approach, it is possible to reduce the volume of 3D metal printing by 32%, which amounts to more than USD 135 in value terms.

Mild low-temperature photothermal therapy demonstrated a distinctive 'hot spring' effect in the multichannel regulation of atherosclerosis instead of inducing foam cell apoptosis

Atherosclerosis (AS), characterized by endothelial injury, progressive inflammation, and lipid deposition, can cause adverse cardiovascular events. However, effectively addressing all these pathological conditions simultaneously is challenging. To devise a comprehensive treatment strategy for AS, we developed a nanoparticle-based mild photothermal therapy (PTT) approach, which controlled the temperature within the range of 42–45 ℃, creating a unique 'hot spring' effect. The nanoparticles used in this therapy consist of a core made of zeolitic imidazolate framework-8 (ZIF-8) nanoparticles loaded with indocyanine green (IR820), and an outer shell made of L-arginine (LA)-modified polydopamine (PDA), which is further modified with hyaluronic acid (HA) to target plaques. In vitro studies have demonstrated that mild PTT can open the TRPV1 channel in foam cells and regulate lipid metabolic diseases by maintaining a controlled temperature range of 42–45 ℃. Furthermore, the LA-PDA shell has anti-inflammatory properties, decreasing NLRP3 expression. Moreover, the eNOS/NO pathway was activated by LA, promoting the healing of injured endothelial cells (ECs). Additionally, the increased temperature enhances HSP90 expression, thereby helping to maintain eNOS. In vivo studies further confirmed that the HLPIZ-guided ‘hot spring’ effect has impressive anti-atherosclerotic capability by scavenging lipids, reducing inflammation, and repairing injured ECs simultaneously. In conclusion, our study confirmed that HLPIZ-guided mild PTT can exhibit a ‘hot spring’ effect, effectively regulating three key pathophysiological processes of AS, being a novel, potentially effective strategy for anti-AS therapy.

Enhancing electromagnetic wave absorption with core‐shell structured SiO2@MXene@MoS2 nanospheres

AbstractMaterial composition and structural design are important factors influencing the electromagnetic wave (EMW) absorption performance of materials. To alleviate the impedance mismatch attributed to the high dielectric constant of Ti3C2Tx MXene, we have successfully synthesized core‐shell structured SiO2@MXene@MoS2 nanospheres. This architecture, comprising SiO2 as the core, MXene as the intermediate layer, and MoS2 as the outer shell, is achieved through an electrostatic self‐assembly method combined with a hydrothermal process. This complex core‐shell structure not only provides a variety of loss mechanisms that effectively dissipate electromagnetic energy but also prevents self‐aggregation of MXene and MoS2 nanosheets. Notably, the synergistic combination of SiO2 and MoS2 with highly conductive MXene enables the suitable dielectric constant of the composites, ensuring optimal impedance matching. Therefore, the core‐shell structured SiO2@MXene@MoS2 nanospheres exhibit excellent EMW absorption performance, featuring a remarkable minimum reflection loss (RLmin) of −52.11 dB (2.4 mm). It is noteworthy that these nanospheres achieve an ultra‐wide effective absorption bandwidth (EAB) of 6.72 GHz. This work provides a novel approach for designing and synthesizing high‐performance EMW absorbers characterized by “wide bandwidth and strong reflection loss.”