Kinds Of Channels Research Articles

Cyclostationarity of Communication Signals in Underwater Acoustic Channels

The effect of underwater acoustic propagation on the cyclostationary features of communication signals is modeled and analyzed. Two kinds of channels are considered: the multiscale-multilag channel, over which mobile and wideband acoustic systems usually communicate, and the dispersive channel resulting from low-frequency modal propagation in shallow water. It is shown that multiscale-multilag channels transform cyclostationary signals into a sum of velocity and acceleration-dependent time-warped cyclostationary processes. This time-warping is carefully taken into account to efficiently recover the cyclostationary features. On the other hand, it is found that low-frequency dispersive channels preserve the original periodicity but attenuate the shorter cycles and spread the correlations. To illustrate the theoretical results, applications with simulated and real data are also presented. Specifically, the problem of estimating time-varying Doppler scales is addressed for multiscale-multilag channels as well as the detection of signals with unique cyclostationary signatures. The example of blind symbol-rate estimation applied to covert communications in dispersive channels is also discussed. Special attention is paid to phase-shift keying (PSK), quadrature amplitude modulation (QAM), orthogonal frequency-division multiplexing (OFDM), and direct-sequence spread-spectrum (DSSS) signals. Accompanying supplementary material provides the MATLAB code used for the estimation and detection examples.

Structures and electrical conductivities of a series of coordination polymers based on tetrathiafulvalene

Three novel tetrathiafulvalene-based coordination polymers, [Co(H2TTFTB) (H2O)4DMF] (1), [Co6(HTTFTB)4(H2O)] (2) and [Mn4(TTFTB)4(H2O)7(DMF)] (3) (H4TTFTB = tetrathiafulvalene tetrabenzoate), were synthesized by simple solvothermal method. These complexes exhibit different topologies: complex 1 shows three-dimensional (3D) hydrogen-bonded framework (HOF) constructed by one-dimension (1D) [Co(H2TTFTB)] chains; complex 2 exhibits a porous 3D framework with three kinds of channels, which consisted of {Co3II(COO)8} SBUs connected with TTFTB4‒ ligands along [0 0 1] direction; the porous framework of complex 3 is composed of two types of helical nanotubes. Electrical conductivity (σ) measurements revealed moderate σ values for these three complexes, among which complex 3 shows the highest value of 3.17 × 10–6 S cm‒1 which is comparable to other promising conductive materials consisting of H4TTFTB ligands.

Experimental and numerical analysis of heat transfer in a dimple pattern heat exchanger channel

In contrast to the predominant herringbone shape of heat plates, a microplate heat exchanger has an array of relatively small dimples. Its number and shape define the characteristics of such a plate heat exchanger. Literature, however, of the flow characteristics in such kinds of channels is scarce. Precise knowledge of the flow specifics in such a channel is of key importance to develop efficient new products. Single-phase water flow and heat transfer in microplate heat exchanger was investigated with the laboratory experiments and use of computational fluid dynamics simulations. A novel and innovative laboratory experiment was developed where flow characteristics and heat transfer in the microplate heat exchanger were measured. Experimental results were directly used as boundary conditions in numerical simulations. With this approach a direct validation of the results of numerical simulations were obtained. Heat transfer simulations were performed with three turbulence models: k- ε, k-ω SST and the Reynolds stress model. The most reliable results in heat transfer analysis were obtained using the Reynolds stress model where results are on average 7.05% lower compared to the results of the laboratory experiment. When all experimental uncertainty contributions were analysed, the simulation results were in the band between − 11% and 1.8% compared to the results of the laboratory experiment. Numerical simulations show that the heat transfer coefficient in the channel is proportional to Re0.64 in the analysed geometry of a microplate heat exchanger. The heat transfer coefficient was calculated and was between 9740 and 21990 W/m2K at Reynolds numbers 1170 and 4170 respectively.

A multifunctional probe based on a heterometallic-organic framework: highly selective detection of 1,3-dinitrobenzene, tryptophan, and visual recognition of pentavalent vanadate ions

Herein, a novel luminescent heterometal-organic framework (HMOF), {[EuZn2(imdc)2(4,4′-bpy) (H2O)4(OH)]·4,4′-bpy}n (1), was synthesized by selecting d-f heterometals and two ligands with abundant coordination sites (H3imdc = 1H-imidazole-4, 5-dicarboxylic acid, 4, 4′-bpy = 4, 4′-bipyridine). The X-ray single crystal diffraction reveals that compound 1 is a three-dimensional framework structure with two kinds of channels, which has good pH fluorescence stability. Compound 1 is demonstrated to be the first known HMOF for selective detection of pentavalent vanadate ions (VO43− or VO3−). It also exhibited high selectivity, sensitivity, and low detection limits for 1,3-dinitrobenzene (1, 3-DNB) and L-tryptophan (L-Trp). More significantly, the portable MOF-based fluorescent paper of compound 1 was also successfully manufactured and might be potentially used as a functional material with naked eye recognition. Furthermore, the fluorescence mechanisms of compound 1 for sensing the above analytes have been elaborated in detail.

Meteorological factors against COVID-19 and the role of human mobility.

In the vein of recent empirical literature, we reassessed the impact of weather factors on Covid-19 daily cases and fatalities in a panel of 37 OECD countries between 1st January and 27th July 2020. We considered five different meteorological factors. For the first time, we used a dynamic panel model and considered two different kinds of channels between climate and Covid-19 virus: direct/physical factors related to the survival and durability dynamics of the virus on surfaces and outdoors and indirect/social factors through human behaviour and individual mobility, such as walking or driving outdoors, to capture the impact of weather on social distancing and, thus, on Covid-19 cases and fatalities. Our work revealed that temperature, humidity and solar radiation, which has been clearly under considered in previous studies, significantly reduce the number of Covid-19 cases and fatalities. Indirect effects through human behaviour, i.e., correlations between temperature (or solar radiation) and human mobility, were significantly positive and should be considered to correctly assess the effects of climatic factors. Increasing temperature, humidity or solar radiation effects were positively correlated with increasing mobility effects on Covid-19 cases and fatalities. The net effect from weather on the Covid-19 outbreak will, thus, be the result of the physical/direct negative effect of temperature or solar radiation and the mobility/indirect positive effect due to the interaction between human mobility and those meterological variables. Reducing direct effects of temperature and solar radiation on Covid-19 cases and fatalities, when they were significant, were partly and slightly compensated for positive indirect effects through human mobility. Suitable control policies should be implemented to control mobility and social distancing even when the weather is favourable to reduce the spread of the Covid-19 virus.

Teaching Robotics: Description Model for Synergetic Combination of Robotics Learning Content

The continuing growth in robotics achieves its goal to support humans in monotonous and physically demanding tasks sustainably. However, a robot colleague must, of course, be further developed, programmed, and maintained. Thus, a significant trend towards training in the field of robotics is emerging for a broad target group of teachers and learners. Unfortunately, there is no uniform description model for the classification of the growing robotics learning content available, making it impossible to compare existing contents and combine them for a suitable curriculum adapted to individual needs. This paper proposes, therefore, such a model for the classification of learning content in the field of robotics for sustainable human-robot work. The classification is based on three pillars (human, robot, and environment) and combines/extends existing classifications and keyword concepts. Not only the learner’s knowledge level and the subject area in robotics are thereby classified, but also the environment used or recommended for this purpose. Finally, three different state-of-the-art robotics learning contents have been classified to outline the broad and general applicability, but also the limitations of the proposed classification. It will be shown that the associated and proposed keywords make it easier for learners to find suitable content in the field of robotics via all kinds of channels. Based on these results, the authors suggest applying this description model within Learning Factories, online learning platforms, and offline robotics courses.

Multi-Dimensional Routing, Wavelength, and Timeslot Allocation (RWTA) in Quantum Key Distribution Optical Networks (QKD-ON)

Currently, with the continuous advancement of network and communication technology, the amount of data carried by the optical network is very huge. The security of high-speed and large-capacity information in optical networks has attracted more and more attention. Quantum key distribution (QKD) provides information-theoretic security based on the laws of quantum mechanics. Introducing QKD into an optical network can greatly improve the security of the optical network. In order to reduce the cost of deployment on QKD infrastructure, quantum signals in QKD and classical signals in optical networks are multiplexed in the same fiber by wavelength-division manner. Moreover, due to the limited wavelength resources in an optical fiber, time-division technology is adopted to construct different kinds of channels in QKD system for efficient utilization of wavelength resources. Under such situation, how to satisfy the security requirements of service requests and complete the efficient scheduling of multi-dimensional resources, i.e., wavelengths and timeslots, is a challenging problem. This paper addresses this problem by considering multi-dimensional routing, wavelength, and timeslot allocation (RWTA) in short-distance quantum key distribution optical networks (QKD-ON), in which any two nodes can directly establish a quantum channel, and the maximum distance between any two nodes is less than the distance that can carry out point-to-point quantum key distribution process. While accommodating services with security requirements in QKD optical networks, to avoid the wavelength time-slot fragmentation caused by the constraints of wavelength consistency and time-slot continuity, we propose a time-window-based security orchestration strategy as well as relative-loss of time continuous compactness based RWTA strategy. We conducted the simulations under various scenarios, e.g., different key updating periods and different distributions on wavelength resources, etc., and the results show that the proposed strategy can achieve better performance compared with the baselines in terms of key success rate, key-updating delay, and blocking probability.

Explicit formulas of normal, alternate and conjugate depths for three kinds of parabola-shaped channels

Comparisons reveal that the 2.5, 10/3 and 3 order parabola-shaped channels improve flow conveyance discharges by 0.68%–7.86% and save construction costs by −0.95 to −27.99% over the common rectangular, triangular, trapezoidal sections, the extensively studied quadratic, semi-cubic and horizontal-bottom semi-cubic parabola-shaped sections. However, few researches on the critical, normal, alternate and conjugate depths, playing key roles in the design, operation and management of open channels, for these three kinds of parabola-shaped channels are available at present. Because the governing equations of normal, alternate and conjugate depths are nonlinear, so these characteristic depths cannot be solved analytically except for the critical depths. The biggest challenges in the calculation of normal depths are the nonintegrable wetted perimeters for the three kinds of parabola-shaped channels. Direct and numerical solutions for wetted perimeters are proposed based on the Gauss-Legendre six points method and the Simpson numerical integral method, respectively. Then, three direct solutions of normal depths are proposed using exact wetted perimeters based on the Simpson numerical integral method for the three kinds of channels. Subsequently, the specific energy equations are deformed into dimensionless forms. Meanwhile, analytical critical depths are skillfully utilized to obtain dimensionless specific force equations of conjugate depths. Then explicit solutions of alternate and conjugate depths have as well been proposed using iterative equations for alternate and conjugate depths based on the fixed-point iterative method by running 1stOpt software in the commonly using range of engineering. Through error analysis, the maximum relative errors of normal depths h,h',h''; alternate depths hc,hc',hc''; and conjugate (initial and sequent) depths h1,h2,h1',h2',h1'',h2'' for 2.5, 10/3 and 3 order parabola-shaped cross-sections are only 0.34%, −0.15%, 0.001%; 0.13%, 0.12%, 0.099%; and 0.098%, −0.20%, 0.116%, −0.24%, 0.11%, 0.23% respectively. These explicit solutions of 2.5, 10/3 order parabola-shaped channels are proposed for the first time. And, explicit solutions of 3 order parabola-shaped channel have a similar range of application and higher precision than that of former studies.

Distributed resilient filtering of large-scale systems with channel scheduling

This paper addresses the distributed resilient filtering for discrete-time large-scale systems (LSSs) with energy constraints, where their information are collected by sensor networks with a same topology structure. As a typical model of information physics systems, LSSs have an inherent merit of modeling wide area power systems, automation processes and so forth. In this paper, two kinds of channels are employed to implement the information transmission in order to extend the service time of sensor nodes powered by energy-limited batteries. Specifically, the one has the merit of high reliability by sacrificing energy cost and the other reduces the energy cost but could result in packet loss. Furthermore, a communication scheduling matrix is introduced to govern the information transmission in these two kind of channels. In this scenario, a novel distributed filter is designed by fusing the compensated neighboring estimation. Then, two matrix-valued functions are derived to obtain the bounds of the covariance matrices of one-step prediction errors and the filtering errors. In what follows, the desired gain matrices are analytically designed to minimize the provided bounds with the help of the gradient-based approach and the mathematical induction. Furthermore, the effect on filtering performance from packet loss is profoundly discussed and it is claimed that the filtering performance becomes better when the probability of packet loss decreases. Finally, a simulation example on wide area power systems is exploited to check the usefulness of the designed distributed filter.

Analysis of total signal decay and capacity of information data in wireless atmospheric communication links. Part 2

Introduction: Analysis of total signal decay is based on prognosis of the total path loss occurring in the atmospheric communication links, accounting for effects of gaseous structures attenuation and scattering, hydrometeors (rain, snow and clouds) absorption and attenuation, and turbulent structures fast fading on radio and optical signals passing atmospheric channels with fading. Purpose: To perform a novel methodology of definition and estimation of effects of decay, absorption, scattering, and fading of radio and optical signals propagating in atmospheric channels in various meteorological conditions. Results: Wasanalyzed the impact of gaseous structures, hydrometeors and turbulent structures in total path loss for link budget design and in degradation of data stream parameters, such as capacity, spectral efficiency and bit-error-rate, which lead in loss of information data signals passing such kinds of channels with fast fading and decrease of quality of service. An optimal algorithm was found of the total path loss prediction for various meteorological situations occurring in the real atmosphere at different heights and for various frequencies of radiated signals. A method was proposed of how to evaluate the data stream parameters, capacity, spectralefficiency and bit-error-rate, accounting for the effects of atmospheric turbulence impact on fast fading, which corrupts information passing such kinds of channels. All practical tests were illustrated by the use of the MATLAB utility. A new methodology was proposed on how to evaluate and estimate the capacity, the spectral efficiency, and the loss in energy and in the information data stream for different scenarios of radio and optical signals propagation via atmospheric channels with fading caused by different meteorological conditions. Practical relevance: The results obtained allow to achieve better accuracy of prognosis and increase quality of service in atmospheric communication channels.

The ionothermal synthesis of a new 3-D framework based on classic β-[Mo8O26]4− anions

An unusual metal-organic framework, {H[Ag(I)L][Mo(VI)4O13]}n (1) (L=(4-((1H-1,2,4-triazol-1-yl)methyl)phenyl)methanol)), has been obtained under ionothermal conditions. According to the single-crystal X-ray diffraction analysis, 1 is a new 3-D framework based on β-[Mo8O26]4− type polymolybdate anions with two kinds of channels (A and B) along the b-axes and c-axes in the framework. The neighboring inorganic Mo8-Ag chains are linked by the organic ligands through the Ag centers resulting in 2-D layers. These adjacent 2-D layers extend into a 3-D framework through Ag1 nodes and β-[Mo8O26]4− anions, respectively, resulting in a topological symbol (64 · 82)2(64 · 82). In addition, the gas adsorption, proton conduction and luminescent properties of 1 are also discussed in detail. Moreover, the electrochemical impedance spectroscopy (EIS) measurements show a conductivity (1.9 × 10−4 S cm−1 at 65 °C and 95% relative humidity (RH)), with an activation energy of 0.41 eV for 1. The mechanism of proton conduction for 1 is proved to be the vehicular mechanism.

Decomposing information into copying versus transformation.

In many real-world systems, information can be transmitted in two qualitatively different ways: by copying or by transformation. Copying occurs when messages are transmitted without modification, e.g. when an offspring receives an unaltered copy of a gene from its parent. Transformation occurs when messages are modified systematically during transmission, e.g. when mutational biases occur during genetic replication. Standard information-theoretic measures do not distinguish these two modes of information transfer, although they may reflect different mechanisms and have different functional consequences. Starting from a few simple axioms, we derive a decomposition of mutual information into the information transmitted by copying versus the information transmitted by transformation. We begin with a decomposition that applies when the source and destination of the channel have the same set of messages and a notion of message identity exists. We then generalize our decomposition to other kinds of channels, which can involve different source and destination sets and broader notions of similarity. In addition, we show that copy information can be interpreted as the minimal work needed by a physical copying process, which is relevant for understanding the physics of replication. We use the proposed decomposition to explore a model of amino acid substitution rates. Our results apply to any system in which the fidelity of copying, rather than simple predictability, is of critical relevance.

Reliable fusion estimation over sensor networks with outliers and energy constraints

SummaryThis paper provides a reliable fusion scheme over sensor networks subject to abnormal measurements and energy constraints. Two kinds of channels are employed to implement the information transmission in order to extend the lifetime. Specifically, the one has the merit of high reliability by sacrificing energy cost and the other reduces the energy cost but could result in packet loss. For the addressed problem, a χ2 detection in local state estimator is first designed to remove abnormal measurements, which could come from outliers or a malicious modification by attackers. Then, a new strategy is developed to compensate the lost local estimation transmitted by low‐reliable channels. Furthermore, by view of matrix operation and probability theory, a set of recursive formulas are developed to calculate desired error covariance matrices of local state estimation, compensated state estimation as well as fusion estimation. The optimal fusion weights are obtained analytically and the advantage of fusion estimation is disclosed by resorting to these covariance matrices. Finally, a numerical example is used to illustrate the effectiveness of the proposed method.

EFISIENSI PEMASARAN JAGUNG DI KELURAHAN KALAMPANGAN KECAMATAN SABANGAU KOTA PALANGKA RAYA

The aim of this research is to analyze marketing channel, marketing institution, marketing function, marketing margin, marketing cost, marketing profit, corn farmer's share, marketing efficiency of maize in various channel in Kalampangan village. The results showed that: (1) marketing of corn in Kalampangan village there are two kinds of channels, where channel I involves four institutions namely: farmers, merchants village, retailers, and consumers. While channel II involves two institutions only, namely, farmers as traders and consumers. Maize's marketing functions are: sales function, purchasing function, storage function, transport function and facility function. (2) From calcution result at Marketing Channel I, total marketing margin of maize in Kalampangan Villge is Rp. 3.860,-/kg, total cost of corn marketing is Rp. 310,-/kg, total profit of corn marketing is Rp. 3.550,-/kg and the result obtained by corn farmer are 58,04%. From calculating result at Marketing Channel II, total margin of maize in Kalampangan Village is Rp. 2.160,-/kg, total cost of corn marketing is Rp. 310,-/kg, total profit of corn marketing is Rp. 1.850,-/kg and the result obtained by corn farmer are 71,20%. (3) marketing efficiency at Marketing Channel I equal to 41.96%, and on Marketing Channel II is 28,80%. Marketing efficiency value in Channel I is lower than marketing efficiency II, it is considered more efficient marketing Channel II.

Design and performance of analog circuit for the wide field of view Cherenkov telescope array of LHAASO

The Wide Field of View Cherenkov Telescope Array (WFCTA) is an important part of the Large High Altitude Air Shower Observatory (LHAASO) project. A high-resolution and low-relative deviation charge measurement is required over a dynamic range of 10 photoelectrons (p.e.) to 32,000 p.e. in the electronics readout system of the WFCTA. The analog circuit is one of the crucial parts in the electronics readout system. Because of the large dynamic range of the signals, a dual-gain electronics channel has been designed. In other words, for the signals from a SiPM, we designed two channels with the similar structures and different gains When these two kinds of channels are placed on two different Printed Circuit Boards (PCBs), it reduces the crosstalk between the large gain channels and the small gain channels. Tests have been conducted to evaluate the performance of the electronics readout system under different temperature conditions. Results indicate that accurate charge measurements can be achieved, ranging from 10 p.e. to 32,000 p.e., and that the system is capable of adapting to the temperature environment of the plateau where the altitude is more than 4000 m.

Nitrogen Coordination To Dramatically Enhance the Stability of In-MOF for Selectively Capturing CO2 from a CO2/N2 Mixture

Two In-based metal–organic frameworks (MOFs) have been designed and synthesized by the reaction of 3-phenylpyridine polycarboxylic ligands and In3+ cations: In3L14·(CH3NH2CH3)3 (H3L1 = 5-(3′,5′-dicarboxylphenyl)nicotic acid; 1) and In2L22(CH3COO)2·(CH3)2NH2·(CH3)3NH·H2O (H3L2 = 3-(2,4-dicarboxylphenyl)-6-carboxylpyridine; 2). Single-crystal X-ray diffraction analysis indicates that the In3+ centers in 1 are all coordinated by eight oxygen atoms from four carboxylate groups, resulting in a 3D framework with two different channels A and B with sizes of 14.4 × 8.75 and 7.24 × 6.7 A2, respectively. In 2, each In3+ center was coordinated by six carboxylate oxygen atoms and a pyridine N atom, forming a 2D layerlike structure. These 2D layers are further fused together via electrostatic interactions into a 3D supramolecular framework, showing two kinds of channels A′ and B′ with pore sizes of 5.25 × 9.69 and 4.29 × 8.66 A2, respectively. In this work, the coordination of N to the In3+ center in 2 was first achie...

A Study on Natural Circulation Flow Rate for Various Shaped Channels

The severe accident in Fukushima daiichi nuclear power plant revealed the importance of molten core cooling system without the electric power, then cooling system by natural circulation flow has attracted attention. The heat removal performance of this system depends on the natural circulation flow rate, so it is essential to predict the flow rate accurately for the safety design. The purpose of this study is to develop the evaluation method for the natural circulation, and to examine its accuracy dependence on the channel shape. Experiments were carried out at atmospheric pressure, using room temperature air-water flow. We used seven kinds of channels with various shape and diameter, and measured natural circulation flow rate and pressure drop for each channel. Predictive analysis was conducted by our method based on balance between driving force and pressure drop in the loop channel. The major results are as follows: (1) It is possible to predict the natural circulation flow rate with an error of less than 20 percent for various shaped channels. The average and standard deviation for the ratio between calculated and experimental flow rate is 0.98 and 0.047. (2) Two phase prediction method for pressure drop has maximum 15 % error. To improve the prediction accuracy, it is important to improve the prediction of the void fraction and the two-phase multiplier.

VALUE CHAINS ANALYSIS ANALYSIS OF ORGANIC VEGETABLES (Case Study at Mulyo Santoso Farmer Group in Sukun District of Malang City)

ABSTRACT: Increased income and healthy lifestyle trend encourage people to switch to consuming non-organic food products to organic food products. This encourages producers in developing organic vegetable business. This research was conducted for the development of organic vegetable business by using value chain analysis. Respondent determination was done by census as many as 30 farmers of organic farming at MulyoSantoso Farmer Group in Malang City, and the determination of merchant respondents using snowball sampling. The results show that farmers earn the smallest margin compared to other actors this is because the price received by farmers is determined by the trader. Organic vegetable marketing channel there are four kinds of channels, where farmers who can sell directly to consumers will get the highest profit. This is also related to the efforts of farmers in increasing the added value in processing vegetables into chips and sauces, where farmers are able to increase added value then the profits are also increased. The results of Benchmarking and Upgrading indicate that increasing the added value and capability of farmers to increase production capacity and harvesting the utilization of technology needed to reduce losses post-harvest.

A translucent honeycomb solar collector and thermal storage module for building façades

An innovative new translucent honeycomb solar collector and thermal energy storage module has been designed. The honeycomb module contains two different kinds of channels, namely empty ones and those that are filled with a Phase Change Material (PCM). The latter are sealed at the front and back side and, therefore, form chambers. Solar radiation enters the empty channels and is transmitted forward into them. The absorbed energy fraction at the side walls of these empty chambers leads to a melting of the PCM in their neighboring filled chambers, where then thermal energy is stored as latent heat. A heat transfer fluid, usually air, crosses the empty channels by forced convection and additionally charges or discharges the storage modules. Such elements are ideal to equip “intelligent” building façades in passive houses or then to form thermal storage elements in decentralized air-conditioning systems by integration into the façade of e.g. an office building. This first article presents the innovative solar system and gives new results on simplified two-dimensional temporal-spatial physical modeling, numerical simulation of charging and discharging modes and of a combined mode for a typical practice case. The content of a second planned article on system optimization and full system performance, including the description of thermal behavior of system/building combinations is roughly sketched in the section ‘Conclusions and Outlook’.

Experimental study of supercritical water heat transfer deteriorations in different channels

The experimental tests on heat transfer deterioration (HTD) of supercritical water flowing in 4 different kinds of channels, including tube, annular channel, and 2 × 2 bundle, have been carried out on the Supercritical WAter MUltiPurpose test loop (SWAMUP). The tube is made of Inconel alloy with different inner diameters; the annular channel consists of an Inconel alloy heated inner tube and a 304 stainless steel unheated outer tube. Two kinds of bundles were tested. The first kind of bundle consists of 4 Inconel-718 tubes with different Pitch-to-Diameter ratios, and the 2 × 2 bundle with grid spacers is installed into a square assembly box. The other kind of 2 × 2 bundle consists of 4 heater rods, and the rod bundle with wire wraps is also installed into a square assembly box. The heat transfer of supercritical water in simple channel like tube is stronger with larger cross-sectional flow area, but it is stronger with smaller cross-sectional flow area in complex channel like bundle. Two kinds of HTDs are observed in tube and annular channel, only the first kind of HTD is observed in bundle. The first kind of HTD occurs only at high ratio of heat flux to mass flow velocity in different channels, and the second kind of HTD is more likely to occur in simple channel which could be eliminated in bundle by the transverse turbulent flow. The effects of thermal–hydraulic and structural parameters on the second kind of HTD in tube are as follows: the HTD of supercritical water is severer with higher heat flux and the increment of wall temperature is much larger; the HTD occurs earlier and severer with lower mass flow velocity; the HTD delays and the wall temperature rises more slowly when the pressure rises; and the diameter has no evident effect on this kind of HTD. The heat transfer in bundles especially with wire wraps is qualitatively better and more stable than that in other tested channels. In order to avoid the first kind of HTD within the operating condition of SCWR, the low mass flow velocity condition and high heat flux condition should not occur at the same time during operation.