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The cooling capacity of a typical dilution refrigerator is mainly determined by the circulating flow of the He-3 in the system, which is usually realized by the external circulation pump. In order to increase the concentration of circulating He-3, the still often take the orifice structure to limit the influence of the superfluid helium film, and this structure will also have a certain impact on the flow rate of He-3. This paper summarizes the flow rate models of each part of the orifice structure, and establishes a model related to the influence of pumping speed and the diameter of orifice on the flow rate of circulating He-3. The relationship between pumping speed and flow rate is developed and the relation is divided into three phases for detailed analysis. It is found that the flow rate and the concentration of circulating He-3 increase first and then decrease with the increasing diameter of orifice at a certain pumping speed, and the possible reasons for this phenomenon are analyzed. The results indicate that there is an optimal orifice diameter at a determined pumping speed. [ABSTRACT FROM AUTHOR]

Simple Summary: In 2019, Late Devonian Xinhang forest was reported from Anhui Province, China. It represents the earliest forest in Asia and China, and was regarded as monospecific with numerous small trees of the lycopsid. Recently, we found some other plants from the forest and now erect a new fern-like plant named Xinhangia. It is small with height of tens of centimeters, and usually has two orders of branches in alternate and sometimes triseriate pattern. Spines densely occur on the main axes and primary branches. Its leaf-like organs are very simple and dichotomize into recurved tips. Fertile organs are similar to the "leaves" but terminated in elongate and paired sporangia. Both the "leaves" and fertile organs are alternately arranged on secondary branches. In anatomy, the primary xylem is "8"-shaped and is surrounded by secondary xylem. With simple characters, Xinhangia represents a morphologically primitive plant and is of uncertain affinity at class or order level. As a component of Xinhang forest, Xinhangia will help understand the growth habit and habitat of fern-like plants, as well as the structure and ecology of ancient forests in the future. Palaeozoic fern-like plants show great diversity in their morphology and/or anatomy. Within this group, a novel taxon, Xinhangia spina gen. et sp. nov., is now reported from the Upper Devonian (Famennian) Wutong Formation of Anhui Province, China. The primary and secondary branches are borne alternately and sometimes in a triseriate pattern. Spines are evident on the main axes or stems and on the primary branches. Vegetative ultimate appendages with recurved tips are alternate, usually dichotomous 1–2 times, and sometimes as an aphlebia located at the base of primary or secondary branches. Fertile ultimate appendages are alternate, usually dichotomous 1–2 times, and terminate in elongated and paired sporangia. The stele has a clepsydroid-like primary xylem with each end bearing a protoxylem strand. The secondary xylem surrounding the primary xylem illustrates uniseriate rays. With rare divisions in both the vegetative and fertile ultimate appendages, Xinhangia represents a morphologically primitive plant. It is of uncertain affinity at the class or order level. The stelar architecture suggests that the clepsydroid stele may not be emphasized in discussing the relationship among fern-like plants such as rhacophytaleans. [ABSTRACT FROM AUTHOR]

Tree lycopsids prospered in the Late Devonian and constituted a major part of the Late Paleozoic forest ecosystem that deeply impacted the Earth's climate. However, the fertile organs of these early tree lycopsids display low morphological disparity, which has hampered further knowledge about their ecological habit. Here, we report Omprelostrobus gigas gen. et sp. nov. from the Upper Devonian (Famennian) Wutong Formation at Changxing, Zhejiang, China. The collection includes aerial axes, strobili and associated roots. The strobili are the largest among coeval lycopsids to our knowledge, and are divided into proximal and distal portions by dimorphic sporophylls with differentiated laminae and probable strong photosynthetic capacity. The associated but not attached roots displaying multiple isotomous branches lack rootlets and typical rootlet scars. The varied strobili sizes of early tree lycopsids were relatively independent of their body plan, but the large strobili could suggest increased reproductive investment to overcome the disadvantages of the disturbed flooded habitat. A new species of Late Devonian fossil lycopsid with large strobili and differentiated sporophylls provides insight into reproductive investment of early tree lycopsids. [ABSTRACT FROM AUTHOR]

The earliest ovules in the Late Devonian (Famennian) are surrounded by a cupule that is involved in both protection and pollination, and generally have free integumentary lobes. Here we report a new taxon from the Famennian of China, Guazia dongzhiensis gen. et sp. nov. The terminally borne ovule is apparently acupulate (without cupule) and has four radially arranged wing-like integumentary lobes that are extensively fused, and folded lengthwise and inwards. Guazia provides evidence that not all Devonian seeds possess a cupule and it increases their diversity in integumentary lobes. This genus also suggests that the integuments develop new functions, probably including wind dispersal at the expense of the cupules. [ABSTRACT FROM AUTHOR]

This paper presents a fully integrated high-frequency (HF) radio-frequency identification (RFID) tag chip based on the ISO/IEC 15693 and discusses a series of design techniques, including analog and digital control circuits. In order to get a more coupled power supply, an amplitude shift keying demodulator with very low modulation index is proposed. Moreover, modulator, limiter, and electrostatic discharge circuit are mentioned to make the tag IC work effectively and reliably. Besides, digital control circuit with 2-kbit EEPROM memory is designed to help the tag operate correctly under a very low magnetic field. The proposed RFID tag IC was fabricated using a 0.18-μm 2P6M CMOS technology with an area of 926 μm by 855 μm and a power consumption of less than 120 μA. Data rates of 6.62–52.97 kb/s are supported. The tag can operate under a minimum magnetic field of 0.12 A/m and a minimum modulation index of 2.33% which is far less than 10% required by the RFID standard. Compared with the prior references, the proposed tag IC has better performances especially in the aspect of low modulation index. [ABSTRACT FROM AUTHOR]

Shougangia bellafrom the Late Devonian (Famennian) of South China is a fern-like plant known for its morphology and now provided with anatomy and a reconstruction. Its stems contain a dissected stele with a four-ribbed and an elongate-curved primary xylem segments changing to three elongate and slightly curved segments. Primary branches have a dissected stele with three similar primary xylem segments as in stems. The primary xylem of the stems and primary branches is mesarch, and individual primary xylem segments bear peripheral protoxylem strands and are surrounded by secondary xylem.Shougangiais anatomically compared with fern-like plants, zygopterid ferns and early seed plants, verifying its uncertain affinity at class and order levels as suggested by morphology, or representing a new order within the Cladoxylopsida. On the basis of anatomy and branching pattern, it is emphasized that most fern-like plants appear evolutionarily closely related to iridopteridaleans. Secondary xylem is involved not only in mechanical support, but also more likely in enhancing water supply for fern-like plants includingShougangia. By the Late Devonian, besides the abrupt drop of atmospheric CO2levels, the presence of secondary xylem may correlate well with the primary radiation of leaves (megaphylls) of euphyllophytes (e.g. fern-like plants, sphenopsids, progymnosperms and seed plants). [ABSTRACT FROM PUBLISHER]

Studying the effect of oxygen in coal oxidation is very important for understanding and controlling coal spontaneous combustion. However, the oxygen effect is not very easy to determine clearly due to the large effect of heat source on coal oxidation in temperature rising experiments. Here, focused on sub-bituminous coal, the oxygen effect was separated from coal oxidation by continuously measuring FTIR spectra of coal with respect to varying temperatures and under oxygen and nitrogen. The active groups’ real-time changes of coal oxidation, thermal treatment and oxygen effect were measured. The carboxylic ester and carboxyl units are the main functional groups that increase with temperatures increasing under oxygen and nitrogen, while the other functional groups decrease in quantity. The oxygen effect promoted the consumption of aliphatic hydrocarbons and hydroxyl groups and also promoted the formation of oxygen-containing groups (except hydroxyl). Four characteristic temperature stages involved in the oxygen effect and their key functional groups were identified. Simultaneously, the relationship of oxygen consumption and chemisorption in oxygen effect was analyzed. The starting temperature of oxygen chemisorption is between 50 and 60°C. The maximum contribution of oxygen effect was observed in methyl and methylene groups. These results are important for chemical control of coal spontaneous combustion. The oxidation of aliphatic hydrocarbon should be controlled before oxygen chemisorption. The value of oxygen consumption between 70 and 80°C can be measured accurately due to the constant chemisorption rate, which help to identify the tendency for spontaneous combustion. These results will help in better understanding of the reaction mechanism of coal oxidation, especially the oxygen effect. [ABSTRACT FROM AUTHOR]

The Late Devonian (Famennian) witnessed the diversification of early seed plants (spermatophytes), which usually possess cupulate ovules as their female reproductive organs. Previous studies have described two such plants with uni-ovulate cupules from South China. Here, a new seed plant, Calycosperma qii gen. et sp. nov., is reported from the Upper Devonian Wutong Formation of Changxing County, Zhejiang Province, China, exemplifying the first occurrence of multi-ovulate cupules in South China and eastern Asia. This plant shows cupulate ovules and associated synangiate pollen organs. Cupules are goblet-shaped with the basal two-third fused and the distal one-third dissected into 16 linear tips. Each cupule bears two ovules at the bottom, below the bases of linear tips. Synangiate pollen organs terminate isotomously divided fertile branches and consist of three to six basally fused elongate microsporangia. The considerably fused cupule of Calycosperma suggests an earlier differentiation of multi-ovulate cupules in Famennian. Calycosperma shows the largest cupules among the known Devonian seed plants, which are inferred to provide greater protection to ovules and possibly imply a hydrochoric reproduction strategy for this plant. [ABSTRACT FROM AUTHOR]

A heterosporous lycopsid plant is described from the Upper Devonian (Famennian) Wutong Formation, Changxing County, northern Zhejiang Province, China. The plant is known for its terminal and many detached megasporangiate strobili, most of which do not have sporophylls preserved. Some megasporangiate strobili are closely associated with a vegetative axis bearing leaf cushions and with a mass of microspores. Because of the monosporangiate strobili, the present lycopsid belongs to the Dichostrobiles of the Isoёtales sensu lato. This lycopsid conforms to Changxingia in the vegetative leaves, leaf cushions (including leaf scar and ligule pit), some parts of the megasporophyll (pedicel, heel and lamina), the megasporangium and the megaspores, although the branching pattern of axes, the arrangement and other parts of megasporophyll are still unknown. The fossils are described as Changxingia sp., and this genus is expanded with character of microspore. Hence, the previous and present data indicate that the earliest lycopsids with monosporangiate strobili from the Upper Devonian of China are consistent in Lagenicula megaspores with gula and Lycospora microspores with equatorial cingulum. In contrast, the Carboniferous lycopsids with monosporangiate strobili in Euramerica and Cathaysia show great diversification of both megaspores and microspores. [ABSTRACT FROM AUTHOR]

Pollen organ Telangiopsis sp., associated with but not attached to vegetative fronds, has been collected from the Upper Devonian (Famennian) Wutong Formation, Dongzhi County, Anhui Province, China. Fertile axes with terminal pollen organs are dichotomous for 2–4 times and may be proximally attached by fragmentary pinnules. Pollen organs are synangiate and borne on the top of a short stalk. Synangia are radial in symmetry and each consists of 4–8 elongate microsporangia fused at base. Microsporangia have a longitudinal dehiscence line and show a tapered apex. The associated stem is spiny and bears a vegetative frond which bifurcates once at the basalmost part. Frond rachises possess one order of pinna arranged alternately. Pinnules are borne alternately, planate, highly dissected, and equally dichotomous for 2–3 times. Comparisons among Late Devonian seed plants recognize several branching patterns in the fertile fronds/axes bearing terminal pollen organs. Telangiopsis sp. reinforces that the Late Devonian pollen organs are synangiate usually with basally fused microsporangia. It is suggested that the evolutionary divergence of radial and bilateral symmetries of pollen organs may have occurred in the Famennian, when the earliest seed plants evolved planate and sometimes laminate pinnules. [ABSTRACT FROM AUTHOR]

Late Devonian Minostrobus chaohuensis is one of the earliest monosporangiate-strobilate isoetaleans. Based on new material of this plant, the vegetative axis and microsporangiate strobilus are studied in detail, and the whole plant knowledge is summarized. The vegetative axis is isotomously branched. The stem is up to 55 mm in diameter with helically arranged leaf cushions. Stems and thick branches bear long fusiform leaf cushions and interareas with vertical linear ornamentations. A ligule pit, oblanceolate leaf scar, and vascular bundle scar appear on the leaf cushion. Distal axes have persistent lanceolate leaves and rhombic leaf bases. The microsporangiate strobilus is cylindrical in shape, possesses sporophyll with alate pedicel and long triangular lamina, uniseriate sporangial wall, subarchesporial pad inside the sporangium, and microspore with cingulum. Based on comparisons with other isoetaleans, the usage of the terms “leaf cushion” and “leaf base” is discussed, and Minostrobus chaohuensis is considered as a tree-like lycopsid. It suggests that arborescent isoetaleans with monosporangiate strobili had appeared and diversified in the Late Devonian. The multi-dichotomous branching system of Minostrobus provides new data on the evolution of growth architecture in rhizomorphic lycopsids. [ABSTRACT FROM AUTHOR]

The remarkable differences between the infrared spectra of oxygen adsorption and nitrogen desorption in coal have been experimentally and theoretically investigated. Density functional theory calculations were performed to better explain the mechanism of oxygen adsorption using six different molecular models of coal. In addition, the remarkable differences of infrared spectra between oxygen adsorption and nitrogen desorption was defined as the indexV, which was used to classify the spontaneous combustion tendency of coal. The experimental data indicated that the spectra in the 4000–2000 cm−1and 1250–1050 cm−1regions exhibited significant changes. These results suggest that the mechanism of oxygen adsorption is the alteration and transfer of charge density around the activated sites, which leads to the observed changes of the infrared spectra. TheV, which is related to the alteration of spectral intensity, is found to decrease with the increase of adiabatic oxidation time and the relative spontaneous combustion period of coal. This observation solidifies the connection between sample spectral intensity and oxygen chemisorption. These data suggest that the hydroxy in hydroxy and carboxyl groups on the surface of coal particles is the site of oxygen chemisorption, and theVcan be used to rapidly and accurately categorize the spontaneous combustion tendency of coal. [ABSTRACT FROM PUBLISHER]

Aiming at the complexity of coal structure and reaction, based on the analysis of active group species, structure and its transformation characteristics in coal reaction, the paper comprehensively constructed the active structural unit in the process of coal spontaneous combustion for the first time. Using the frontier orbital theory and quantum chemical calculation to analysis the complete reaction path, activation energy and the heat release of electron transfer in reactions of the active site, the 13 elementary reaction were obtained. The order and relationship of the reactions in coal spontaneous combustion was also built. Based on the research results, the coal oxidation dynamics theory was presented in the paper, which is a chemical chain cycle caused by oxygen with low activation energy, and converts the coal native structure to carbon free radicals releasing the gaseous products. The reaction mechanism of heat and products was illustrated in the oxidation dynamics theory of coal spontaneous combustion. The theory was successfully applicated in categorizing the spontaneous combustion tendency of coal and developing highly-effective chemical inhibition technology to prevent coal spontaneous combustion. [ABSTRACT FROM AUTHOR]

Abstract: The extinction coefficient differs for different functional groups making the quantitative analysis of their infrared spectra problematic. Although the coefficients of some functional groups have been researched previously, they are inaccurate because of deviations in techniques used and linear fitting. The distribution and structural characteristics of functional groups from coal infrared spectra is therefore inaccurate. In this study, quantum chemistry methods are used for the quantification of coal infrared spectra based on the Beer–Lambert law. The effect of the extinction coefficients of different functional groups is eliminated. The experimental infrared intensities, unit absorption intensities and their ratios are obtained to calculate the percentage composition of coal functional groups and molecular structure parameters. Accurate distribution and structural characteristics of coal functional groups are obtained. A linear relationship between the distribution of some functional groups and structural parameters is obtained. Multiple structural parameters are used to determine the grade and maturity of coal samples. The ethylene in coal oxidation experiments below 200°C is consistent with the hydrocarbon-generating potential parameters. These results will improve the accuracy of the quantitative analysis of infrared spectra for determining coal structural features and provide an index for the utilization and prevention of the spontaneous combustion of coal. [Copyright &y& Elsevier]

Coal spontaneous combustion (CSC) is one of the main disasters in the process of coal mining. In this paper, the important role of high-latent heat phase change material CH3COONa·3H2O (SAT) in controlling CSC was studied and compared with common inhibitors (NaCl, CaCl2, ascorbic acid (VC)). The thermal performance characteristics of SAT were revealed by the C80 micromanometer, and the effects of different inhibitors on the thermal behavior of Shengli lignite were analyzed and compared. Furthermore, the gas–solid coaxial fixed bed measurement system was used in conjunction with the Pfeiffer online mass spectrometer, to design the natural temperature rise experiment of coal after the heating interruption in the same programmed temperature rise interval, investigating the effects of different inhibitors on the temperature and gas production in the process of coal oxidation. The results show that the heat absorption effect of SAT is more significant than common inhibitors, which not only improves the heat absorption rate of the samples but also increases the total heat absorption of the sample by 236.6 J·g−1 compared with the raw coal. In the programmed temperature rise experiment, the maximum temperature point of the SAT-inhibited coal sample is reduced by 15.5% compared with raw coal, the time to reach the maximum temperature point is delayed by 20.5%, and the SAT inhibitor effectively inhibits the production of CO and CO2 gases. The method described in this paper provides a new idea for the prevention and control of CSC. [ABSTRACT FROM AUTHOR]

Moisture has a complex influence on the spontaneous combustion tendency of coal. The exothermicity of four different ranks of coal (lignite, gas coal, fat coal, and anthracite) with different total moisture contents during the oxidation process was tested by TA-DSC (Thermogravimetric Analysis- Differential Scanning Calorimetry). It was found that, for different ranks of coal, the effect of the moisture content can be quite different and for the same rank of coal, different moisture contents will affect the coal's exothermicity in very different ways. In addition, the critical moisture content at which the coal is most highly prone for spontaneous combustion was also obtained. It was found that different ranks of coal have different critical moisture contents. For lignite and anthracite, the critical moisture content was 25% and 20%, respectively. For the gas coal and fat coal, the lower the moisture content is, the greater the chance for the coal to have spontaneous combustion. [ABSTRACT FROM PUBLISHER]

A mild and efficient synthesis of N-substituted-3-aryl-3-(4-hydroxy-6-methyl-2-oxo-2 H-pyran-3-yl)propanamides via four-component reaction of an aldehyde, amine, Meldrum's acid, and 4-hydroxy-6-methyl-2 H-pyran-2-one in the presence of benzyltriethylammonium chloride (TEBAC) in aqueous medium is described. This method has the advantages of accessible starting materials, good yields, mild reaction conditions, and begin environmentally friendly. [ABSTRACT FROM AUTHOR]

Kunia venusta gen. et sp. nov. is reported from the late Middle Devonian (Givetian) Haikou Formation near Kunming City, Yunnan Province, China. This plant has three orders of naked axes that divide pseudomonopodially. The second- and third-order axes occur in a helix. Fertile appendages are distantly spaced and helically inserted to the third-order axis; they comprise equally dichotomous branches terminated by two clusters of paired and fusiform sporangia. Sterile appendages are dichotomous and distally recurved. A comparison is made with the basal euphyllophytes including the trimerophytes, cladoxylopsids, zygopterids, stauropterids, and some relevant genera of uncertain affinity. The new plant resembles them in dichotomous appendages with terminal elongated sporangia, but differs mainly in the three orders of pseudomonopodial axes bearing helical laterals. It is thus placed in the Euphyllophytina as incertae sedis. It is suggested that an evolutionary divergence in the branching pattern and appendage morphology might have occurred in the Middle Devonian euphyllophytes, that is, maintaining three dimensions versus yielding more or less planation. [ABSTRACT FROM AUTHOR]

To solve the problem of high dust concentration caused by rock tunnel excavation, in view of the characteristics of dust produced and analyzing the processes of roadheader cutting rock, the paper used Fluent software to carry on numerical simulation of dust movement and analyse the dust characteristics of motion and concentration distribution. Simultaneously, this paper designed the foam dust suppression system applied to fully mechanize large cross-section rock tunnel excavation on the principle of foam dust suppression, and put it into application at the driving face of the north main haulage roadway in Zhuxianzhuang Coal Mine, Huaibei Mining Co., Ltd. The results show that the dust concentration on the exhaust section of the driving face, reaches a maximum at the leeward side of dust source. Foam making by the foam dust suppression system can enclose roadheader's cutting head and cover palisades, reaching the results of wetting rock, reducing dust content, depressing the generation of dust and blocking the spreading alleyway. The average dust-settling effect is 86. 2% and 84. 4% for the total dust and respirable dust, and the effect is 3. 6 and 4. 6 times comparing with water spray, achieving a good effect. [ABSTRACT FROM AUTHOR]

Abstract: Serious mine fire disasters have occurred in Northwest China where there are abundant coal resources. For the shortage of water and loess, a large cost of conventional grouting slurry is needed. However, plenty of sand and fly ash resources have been found there. In order to improve the quality of sand injection and reduce the wastage of water during grouting, a kind of new compound material of sand-suspended colloid, which is composed of mineral inorganic gel and organic polymer, was developed in this paper. And the inhibition performance experiments of the sand-suspended colloid were carried out. The results show that the sand-suspended colloid efficaciously affected the oxidation characteristics above the critical temperature during the acceleration oxidation of the lignite and fat-gas coal samples and restrained the oxidation course by increasing the activation energy, so that it reduced the contents of CO and C2H4 and depressed the oxidation rate during the coal spontaneous combustion, and finally inhibited the coal spontaneous combustion. [Copyright &y& Elsevier]

Archaeopteris macilenta is one of the most widespread plants in the Late Devonian. Based on fossils from the Frasnian Huangjiadeng Formation, Yichang District of Hubei Province, for the first time we study in detail the anatomy of this progymnosperm plant in South China. Ultimate axes are protostelic with three xylem sympodia and lack secondary tissue. Penultimate axes are eustelic, bearing eight sympodia and a thin band of secondary xylem. Radially symmetrical sympodia of mesarch primary xylem produce traces of appendages in a spiral arrangement. Archaeopteris macilenta and A. halliana ( A. roemeriana) are dominant in the Frasnian and Famennian, respectively. Comparisons with these two species from other tectonic plates indicate consistent stelar architectures. Global spread, continuous occurrence, and identical anatomy during the Late Devonian indicate that Archaeopteris survived the Frasnian-Famennian extinction event. In this time, endemic genera and cosmopolitan taxa, including Archaeopteris, suggest the palaeogeographic isolation of South China and certain associations with other plates. [ABSTRACT FROM AUTHOR]

For calculating the stiffness function of a structure, the differential equation of the vibration of the structure was divided into the differential equation on the original stiffness function that was known, and Fredholm integral equation of the first kind on the undetermined stiffness function that was unknown. And the stable solutions of the integral equation, when the smooth factor was equal to zero, was solved by the extrapolation with p smooth factors. So the stiffness function of the structure is obtained. Applied examples show that the method is feasible and effective. [ABSTRACT FROM AUTHOR]

A new vascular plant, Hsüa deflexa sp. nov., is documented from the Lower Devonian ((upper) Pragian-lower Emsian) Xujiachong Formation, near Xujiachong village, Qujing District, eastern Yunnan, South China. In three dimensions, the branching system comprises a robust creeping main axis and comparatively slender erect lateral axes inserted oppositely or alternately. The lateral axes depart at right angles from the main axis. Towards the apex, the main axis is perhaps erect with the lateral axes attached at smaller angles. The lateral axes dichotomize equally one to three times in different planes and decrease in diameter and length acropetally. They bear sparse and irregular tiny spines. Apices of a pair of distal lateral axes curve in opposite directions and each terminates in a rounded to reniform sporangium. The sporangium dehisces into two equal valves along an indistinct convex marginal thickening. The xylem is possibly centrarch. This plant fits Hsüa in branching pattern, sporangial characters and xylem maturation.Hsüa deflexa sp. nov. differs mainly from the type speciesH. robusta in the presence of axial spines, perpendicular extension of lateral axes from the main axis and curving of distal lateral axes. Based on the possibly cen-trarch xylem and terminal sporangium, this plant relates to the rhyniophytes (sensu Banks, 1968). In view of the equal sporangial valves with marginal thickenings it resembles the zosterophyllophytes (sensu Banks, 1968).Hsüa is now treated asincertae sedis. [ABSTRACT FROM AUTHOR]

We describe the tracheid ultrastructure of Hsüa deflexa from the Lower Devonian (upper Pragian-lower Emsian) Xujiachong Formation, Qujing District, Yunnan Province, China. Scanning electron microscopy study of fusainized and permineralized tracheids shows that they are of G-type, bearing many irregularly distributed perforations. The cell wall consists of a decay-resistant inner part lining the cell lumen and a nonresistant outer part. The resistant inner part, i.e., the assumed heavily lignified secondary wall, is continuous over the poorly lignified outer part that comprises the primary wall and discontinuous secondary wall. It forms the annular thickening over the discontinuous secondary wall. The heavily lignified secondary wall may be divided into three layers. Minute perforations occur on the entire heavily lignified secondary wall, i.e., between and on the thickenings. Concerning the distribution, density, and diameter of perforations, G-type tracheids of H. deflexa share some characters of S-type tracheids. Based on observations of casts, cell wall perforation is cylindrical, with a smooth enclosing wall and two slightly enlarged ends. Lumen casts of tracheids have been formed in several stages. The tracheid ultrastructure of H. deflexa supports the theory of two depositional processes for the secondary cell wall. It indicates that at the genus level of Devonian plants, G-type tracheids differentiate in wall perforation characters; the chemical diversification of the secondary cell wall might have occurred by the Early Devonian. Moreover, this work adds to our knowledge about the evolution of tracheids and early land vascular plants. [ABSTRACT FROM AUTHOR]

Background: Low temperatures during flowering severely affect crop growth and yield. Methods: This experiment was conducted under potted conditions with LXD 4 and TJH as test materials and pre-sprayed with exogenous ABA at a concentration of 20 mg·L-1 at flowering stage, respectively and then with an average of 15℃ condition for 5 days. Result: The results showed that foliar spraying exogenous ABA effectively inhibited the increase of MDA content and relatively significantly improved the photosynthetic parameters such as Gs and Tr and alleviated the loss of yield factors caused by chilling stress. Compared with spraying water, spraying exogenous ABA can significantly increase the yield per pot of LXD 4 by 6.72~17.77% and TJH by 6.41~37.04% under low temperature conditions. In summary, foliar spraying exogenous ABA ameliorated the effects of chilling stress on the physiological characteristics of adzuki bean leaves and improved yield as a result of improved antioxidant defense mechanisms which impeded lipid peroxidation. Thus, we conclude that foliar spraying exogenous ABA could decelerate the damages caused by chilling stress to some extent. [ABSTRACT FROM AUTHOR]

Introduction: Neutrophils are important participants in the innate immune response. They rapidly and efficiently identify and clear infectious agents by expressing large numbers of membrane receptors. Upon tissue injury or pathogen invasion, neutrophils are the first immune cells to reach the site of injury and participate in the inflammatory response. Materials and methods: A thorough search on PubMed related to neutrophil death or clearance pathways was performed. Conclusion: Inflammatory response and tissue damage can be aggravated when neutrophils are not removed rapidly from the site of injury. Recent studies have shown that neutrophils can be cleared through a variety of pathways, including non-inflammatory and inflammatory death, as well as reverse migration. Non-inflammatory death pathways include apoptosis and autophagy. Inflammatory death pathways include necroptosis, pyroptosis and NETosis. This review highlights the basic properties of neutrophils and the impact of their clearance pathways on the inflammatory response. [ABSTRACT FROM AUTHOR]

Foam is used as an efficient means of dust suppression in underground coal mines. The poor performance of conventional adding device of foaming agent restricts its wide application. The objective of this study is to propose and investigate a new parallel jet adding device (PJAD). Experimental results show that PJAD requires a greater water flow to produce negative pressure than the single stage jet adding device (SJAD) and is harder to generate cavitation. PJAD consumes a less pressure loss than SJAD and realizes any adding proportion below 1%, which is especially suitable for precision addition of foaming agent. A foaming system used for dust suppression is put forward with PJAD adding foaming agent. Field application indicates that foam achieves a far better dust suppression effect than the roadheader water spraying, and the foam cost is significantly reduced due to the low adding proportion of foaming agent. The marked dust suppression effect makes us believe that the proposed PJAD will greatly promote the large-scale application of foam technology used for dust suppression in underground coal mines. [ABSTRACT FROM AUTHOR]

Arteriovenous malformation (AVM)-derived ophthalmic artery (OphA) branches are not common, and their management is very challenging. We evaluated the safety and efficacy of Trans OphA ethanol embolotherapy for these lesions. We retrospectively reviewed 26 patients with AVMs fed by OphA, who underwent transOphA embolization using ethanol from February, 2015 to December, 2019. Sixty-six transOphA embolotherapy procedures (range, 1–4 procedures; mean, 2.5 procedures) were performed. Devascularization degree, visual field, visual acuity, and quality-of-life outcomes were compared and analyzed at follow up (mean, 32.6 months; month range 10–60). Complications were recorded. Twenty-five of the 26 patients (96%) reported complete or > 90% AVM devascularization while one patient (4%) showed > 70% devascularization. Eleven patients (42%) presented with visual acuity impairments; among them, 6 had improvements while 4 were completely relieved. Eight patients (30.7%) presented visual field defects, 3 had improvements while 4 were completely relieved. Ten patients (38.4%) presented with diplopia and exophthalmos with 2 being completely relieved while 6 had major improvements. Bleeding was controlled in all cases (100%). All patients (100%) exhibited cosmetic deformities with 17 being completely relieved. Moreover, all patients (100%) exhibited impaired daily life, which was resolved in 21 patients with 5 patients reporting major improvements. After endovascular treatment, there was no vision loss, death, or permanent disability in any patient. TransOphA ethanol embolotherapy is efficacious and safe for symptomatic resolution or improvement of AVMs fed by OphA with acceptable complications without the risk of visual impairment. [ABSTRACT FROM AUTHOR]

The arborescent lycopsid Sublepidodendron grabaui was widely distributed in the Late Devonian of South China. Its morphology and anatomy have been described, but the microsporangiate strobilus remains unclear. New material collected from the Guanshan Member of the Wutong Formation in Zhejiang Province allowed us to provide more details of this plant. The pseudomonopodial axis without secondary xylem bears medullated stele and branch traces arranged in irregular helices. The lateral branch possesses solid exarch primary xylem. This pseudomonopodial branching system possibly represents the crown or cauline lateral branch. The microsporangiate strobilus contains microspores belonging to the Lycospora granulata Group. The monosporangiate nature of S. grabaui is confirmed, and the classification of Sublepidodendraceae into the suborder Dichostrobiles is supported. The L. granulata Group microspores are suggested to occur not only in bisporangiate strobili but also in monosporangiate strobili. [ABSTRACT FROM AUTHOR]

A novel composite foam material for blocking air leakage in coal mine was developed. In order to examine the performance of the new composite foam, the foaming property, mechanical property, microstructure, thermal stability, and flame resistance of the composite foams, polyurethane foams, phenolic foams, and urea-formaldehyde foams were investigated. The results show that the composite foam had the biggest compressive strength, thermal stability, and flame resistance. Moreover, composite foam had the lowest foaming temperature and shrinkage, indicating that it had small risk in causing spontaneous combustion of coal, and it exhibited good air leakage blocking effect. Field application showed that composite foam could effectively block air leakage in goaf. Thus, composite foam materials were considered to be the potential candidates for blocking air leakage in coal mines to prevent spontaneous combustion of coal. [ABSTRACT FROM AUTHOR]

In order to obtain the optimal key structure parameters of foam nozzle applied to dust control underground coal mine, the design principle of foam nozzle was elaborated. Meanwhile the compressibility of foam was defined and the calculation formula about volume change of foam caused by pressure variation was deduced. From the formula, the volume expansion would occur when the foam flows out the pipeline, if the two gaps were set at the pipeline end symmetrically, the fan-shaped diffusion would appear along the gaps because of the volume expansion. Based on these principles, the internal structure of the nozzle was designed and the key structure parameters were theoretically calculated. By using the experimental system constructed in the lab, a series of optimized experiments were carried out, and the optimum sizes of the key structure parameters were obtained. The foam nozzle with optimum structure parameters was produced, and the simulation spraying experiments and the practical application were carried out using the produced foam nozzle. The results of experiments and application show that the foam nozzle has the advantages, such as large flow quantity, far jetting distance, uniform dispersion and wide diffusion range. Furthermore, the foam spraying from the foam nozzle can effectively cover the dust sources, which will have a remarkable effect on dust control at working face underground coal mines. [ABSTRACT FROM AUTHOR]

The study of a Late Devonian arborescent lycopsid, Sublepidodendron songziense Chen 1977, from the Hsiehchingssu (Xiejingsi) Formation of Hubei Province and the Wutung (Wutong) Formation of Anhui Province, PR China, provides new insight into its holistic architecture and taxonomic affinity. The study allows several interrelated organ species to be integrated into a conceptual whole-plant species, Sublepidodendron songziense Chen emend. Wang Q., Hao, Wang D.-M., Wang Y. et Thomas Denk. The plant consists of a monocaulous trunk growing from a stigmarian rhizomorph, the trunk bearing biseriate, sub-opposite to possibly alternate lateral branches that expand by means of isotomous to slightly anisotomous dichotomies, forming an excurrent canopy. Lateral branches bear terminal Lepidostrobus-like strobili. These strobili are dimorphic, implying separate mega- and microsporangiate strobili considered with the associated organ assemblage, including Triletes-type megaspores, Lepidocarpopsis-like sporophylls, and Lepidophloios-like cauline anatomy. Moreover, lateral branches are caducous, and ulodendroid scars mark the attachment sites of former branches onto the trunk. The plant diagnostically possesses spirally arranged, small, vertically elongated leaf cushions, which have false leaf scars. The presence of ligule cannot be excluded definitely. The characteristics of leaf cushions show considerable variation corresponding to different taphonomic processes, preservational modes and ontogenetic stages so that this plant megafossil has been classified in various ways previously. Based on organic connection and cauline anatomy, a reconstruction of the whole-plant species is tentatively given. We compare this whole-plant species to the type species S. mirabile (Nathorst) Hirmer, and revise Sublepidodendron (Nathorst) Hirmer 1927, suggesting that the genus and its own family Sublepidodendraceae sensu Kra¨usel et Weyland 1949 should be separated from the order Protolepidodendrales sensu Pichi-Sermolli 1958 and referred to the order Isoe¨tales sensu lato and the suborder Dichostrobiles sensu DiMichele et Bateman 1996. Present Ulodendron specimens are the earliest record in the Late Palaeozoic strata, demonstrating that the pseudomonopodial branching architectural form in the arboresent lycopsids had evolved by the Late Devonian (Famennian). Such a woody trunk together with lateral branches (or cauline peduncles), separate mega- and microsporangiate strobili, and rootlet-bearing rhizomorph epitomize the major structural units (or architectural modules) of a true arborescent lycopsid, and S. songziense appears to be the oldest arborescent lycopsid showing an apparently centralized rhizomorph. We suggest that phylogenetically more advanced arborescent lycopsids did not precipitately occur in the Carboniferous, rather they had already evolved by the Late Devonian (Famennian). The widespread genus Sublepidodendron (Nathorst) Hirmer 1927 emend., especially abundant in China, among the Late Devonian–Early Carboniferous floras may represent one of the progenitors of the phylogenetically advanced arborescent lycopsids. [Copyright &y& Elsevier]

Coal fire is the major hazard to energy security and the environment in the world. Liquid CO 2 and liquid N 2 are widely used in coal mines. However, the spontaneous combustion tendency and re-ignition of coal which is dealt with liquid CO 2 and liquid N 2 remain unclear. To solve the problem, this paper studied the pore and oxidation property changes in coal treated by liquid carbon dioxide and liquid nitrogen, applying SEM, isothermal adsorption and thermogravimetric experiments. The results showed that the matrix of coal soaked by liquid CO 2 and liquid N 2 is shrunk due to cold condition in the context of low temperature (236 K, 77 K). The pore and crack are grown with the increase of total pore volume and specific surface area, which result in increased the oxygen absorption capacity, especially when being soaked by liquid N 2. It can be explained liquid CO 2 mainly promotes the increase of mesopores in 3.5 nm – 4 nm. Because of the low temperature of liquid N 2 , new micropores are formed in 0.45 nm–0.55 nm and mesopores in 2 nm–4 nm are increased. After coal is soaked by liquid CO 2 and liquid N 2 , the pore surface becomes rougher and the pore structure for liquid N 2 tends to be more complex. Pore evolution promotes oxygen absorption by the coal, which results in the decrease of characteristic temperatures in coal oxidation and combustion stages. After coal is soaked in liquid CO 2 and liquid N 2, the oxidation and combustion intensity of coal has increased and the average apparent activation energy of oxidation has dropped by 9.65%–11.33% and 15.10%–17.62% respectively, which indicates that their tendency of spontaneous combustion and reignition increases. In all, this study reveals the evolution of pore structure and changes in oxidation property of coal soaked by liquid CO 2 and liquid N 2 , focusing on providing more information for effectively controlling coal spontaneous combustion after using liquid CO 2 and liquid N 2. • The coal mesopores between 3.5 nm and 4 nm increase treated by liquid CO 2. • The coal micropores formation and mesopores increase treated by liquid N 2. • The oxidation activation energy decreases after soaking liquid CO 2 and liquid N 2. • The coal oxidation active is enhanced after soaking liquid CO 2 and liquid N 2. • The liquid N 2 have more significant effect on pore development and oxidation. [ABSTRACT FROM AUTHOR]

• Mechanism functions of CO, CO 2 generation in isothermal smoldering combustion of coal. • Reactive group conversion in isothermal smoldering combustion of coal. • The relationship between CO and CO 2 production and the consumption and conversion of reactive groups. The process of coal smoldering combustion will produce a significant number of CO and CO 2 gases, causing environmental pollution and casualties. It is important to elucidate the law and mechanism of CO and CO 2 generation during coal smoldering combustion. In this paper, the CO and CO 2 production patterns and the relationship of reactive group conversion during isothermal smoldering combustion were investigated by TG-MS and FT-IR. Results reveal that the CO and CO 2 generation curves with time during isothermal smoldering combustion of coal in the first stage conform to the polynomial function Y 1 = A 1 + B 1 t + C 1 t 2 + D 1 t 3 + E 1 t 4 , in the second stage accord with the complex exponential function Y 2 = A 2 + B 2 e kt (k < 0), as well as the CO + CO 2 production curve. The consumption rate function of functional groups during isothermal smoldering combustion is calculated from the CO + CO 2 production curve as v = L · Y CO + CO 2 1000000 V m . As the isothermal temperature rises, the rate of coal combustion in smoldering combustion accelerates, causing an exponential increase in CO + CO 2 emissions and reactive group consumption. The CO and CO 2 emissions vary considerably at different isothermal temperatures, which is due to the increase in the number and type of reactive groups involved in the reaction with rising temperature. During isothermal smoldering combustion of coal, in exception to the direct generation of CO and CO 2 from carboxyl and carbonyl groups, aliphatic hydrocarbons are key groups for the continuous generation of CO and CO 2 , and are also important mediators for the formation of carboxyl and carbonyl groups. The hydroxyl group acts as a reactant at relatively low temperatures and plays an essential role in driving the reaction. The aromatic hydrocarbon is the principal source of CO and CO 2 at higher temperatures. This study will help to forecast the degree of coal smoldering combustion and to control coal smoldering combustion. [ABSTRACT FROM AUTHOR]

Mine fires mainly arise from spontaneous combustion of coal seams and are a global issue that has attracted increasing public attention. Particularly in china, the closure of coal workfaces because of spontaneous combustion has contributed to substantial economic loss. To reduce the occurrence of mine fires, the spontaneous coal combustion underground needs to be studied. In this paper, a computational fluid dynamics (CFD) model was developed for coal spontaneous combustion under goaf gas drainage conditions. The CFD model was used to simulate the distribution of oxygen in the goaf at the workface in a fully mechanized cave mine. The goaf was treated as an anisotropic medium, and the effects of methane drainage and oxygen consumption on spontaneous combustion were considered. The simulation results matched observational data from a field study, which indicates CFD simulation is suitable for research on the distribution of oxygen in coalmines. The results also indicated that near the workface spontaneous combustion was more likely to take place in the upper part of the goaf than near the bottom, while further from workface the risk of spontaneous combustion was greater in the lower part of the goaf. These results can be used to develop firefighting approaches for coalmines. [ABSTRACT FROM AUTHOR]

Coal dust seriously threatens the safety and occupational health of coal mines. Numerical simulation research on the infrared radiation characteristics of diffused coal dust is carried out in fully mechanized working faces based on the optical monitoring problem of dust particles in mine atmospheric environments. The CFD method is applied to obtain the law of dust transport and distribution. Combined with Mie scattering model, the infrared radiation change characteristics and spectral selection of diffused coal dust particles are simulated and analyzed along the working face. The comparison results show the following: the attenuation and scattering characteristics of mine dust particles system are first enhanced, and then they weaken as the distance from dust source increases. The infrared attenuation of mine dust at the center of the vertical cross-section is generally greater than that at the roof and floor in the same location. The dispersion of mine dust directly determines the attenuation contribution of respirable dust to total dust. Moreover, the infrared absorption effect of functional groups in coal causes the infrared attenuation effect of coal dust to have obvious optical selectivity along the roadway, the existing optical “window.” [ABSTRACT FROM AUTHOR]

Abstract: Pauthecophyton gracile gen. et sp. nov. is described from the Lower Devonian (Pragian) Posongchong Formation near Zhichang Village of Wenshan District, southeastern Yunnan, China. This plant consists of pseudomonopodially and dichotomously branched main axes and lateral branches. Some laterals are pseudomonopodially divided producing three to four times dichotomously branched systems terminating in sporangia; other branches are isotomously divided six to eight times terminating in sporangia. Fusiform sporangia are grouped as fertile units; each unit, generally with two, three or four sporangia, is subtended by a branch which generally divides once or twice. Sporangia lacking twisting have a longitudinal dehiscence and contain similarly sized spores with laevigate and folded exine. Pauthecophyton probably occupies a basal position within the euphyllophytes, as one of the earliest divergent clades. It is more similar to the genus Psilophyton Dawson than to others in branching, as well as sporangial shape, terminal position and longitudinal dehiscence; these similarities, more likely to be plesiomorphic characters of the euphyllophytes, indicate that they both belong to the “trimerophyte grade”. The character of twisted sporangia in trimerophytes and the phytogeographic isolation of euphyllophytes in South China are discussed. [Copyright &y& Elsevier]

Abstract: A new plant, Dibracophyton acrovatum gen. et sp. nov., is described from the Lower Devonian (Pragian) Posongchong Formation of Wenshan District, southeastern Yunnan, China. The plant has creeping axes from which arise vegetative and fertile axes. The vegetative axes helically bear lateral dichotomous appendages with curved or round tips. The fertile axes possess terminal strobili with numerous fertile units arranged in irregular helices. Each fertile unit consists of a stalked long-elliptical sporangium, with dehiscence into two equal valves, and two discrete long-ovate bracts covering sporangium from above–below directions. A new genus and species is thus established based on these characters and is temporarily regarded as incertae sedis of Tracheophyta, although it perhaps closes to the barinophytes in affinity. Detailed comparisons with other plants having a similar architecture, i.e., sporangia closely associated with modified vegetative structures, are made. The discovery of D. acrovatum further enriches the composition of the Posongchong flora and demonstrates great morphological disparity of the Early Devonian vascular plants. [Copyright &y& Elsevier]

Abstract: A new species of early vascular plant, Adoketophyton parvulum sp. nov., is described from the Lower Devonian (Pragian) Posongchong Formation of Yunnan, China. The plant is composed of main axes, lateral vegetative branches and isotomous or anisotomous fertile axes. The vegetative axes branch isotomously or pseudomonopodially in three dimensions, with some laterals ending in terminal circinately coiled tips. K-shaped branching and tubercles are preserved. Terminal strobili consist of four vertical rows of fertile units, arranged in opposite and decussate pairs. Each fertile unit comprises a fan-shaped sporophyll and a sporangium attached adaxially by a short stalk at the base of the sporophyll. The strobili and fertile units (sporophylls and associated sporangia) of this new species are much smaller than those of the type species, Adoketophyton subverticillatum, and the ratio of heights of sporangia to sporophyll laminae in the two species shows a large discrepancy. The affinity and evolution of Adoketophyton are discussed. The various leaf-like appendages in plants reported from the Early Devonian of South China are considered a phenomenon of convergent evolution. [Copyright &y& Elsevier]

Abstract: In this article, we present the numerical simulations of a real cylinder head quench cooling process employing a newly developed boiling phase change model using the commercial CFD code AVL-FIRE v8.5. Separate computational domains constructed for the solid and liquid regions are numerically coupled at the interface of the solid–liquid boundaries using the AVL-Code-Coupling-Interface (ACCI) feature. The boiling phase change process triggered by the dipping hot metal and the ensuing two-phase flow is handled using an Eulerian two-fluid method. Multitude of flow features such as vapor pocket generation, bubble clustering and their disposition, are captured very effectively during the computation, in addition to the variation of the temperature pattern within the solid region. A comparison of the registered temperature readings at different monitoring locations with the numerical results generates an overall very good agreement and indicates the presence of intense non-uniformity in the temperature distribution within the solid. Overall, the predictive capability of the new boiling model is well demonstrated for real-time quenching applications. [Copyright &y& Elsevier]