Secondary Disturbances Research Articles

Reduction of Auto-Power Procedure Influence on the Photovoltaic Inverter On-Board Bus System Caused by Pulsed Loads

The article presents an on-board power system designed for ships, aviation, and space vehicles using energy from photovoltaic panels. The power structure includes both DC and high-frequency AC power buses. As a result of pulse loads, this system is exposed to disturbances that cause electronic systems to reboot. To reduce the effect of the appearance of secondary disturbances in the AC bus to which the photovoltaic converter is connected, a new control strategy has been proposed. This strategy improves the operation of the proportional resonant regulator that controls the AC bus current by making the reference values linearly dependent on the DC bus voltage. A prototype of such a system was designed in the laboratory. The FPGA control board was pulse-disturbed, leading to start the auto-power procedure, and additional disturbances were observed in the AC bus for the standard system. Reduction in the impact of these disturbances was achieved using the proposed control method by reaching a limitation of the bus current in dynamic states caused by the auto-power on process from 280% to less than 100% of the steady-state value. Experimental results verified the validity of the proposed method.

Virtual inertia coordination control strategy of DFIG-based wind turbine for improved grid frequency response ability

The capability of the inertia response of the Double fed induction generator (DFIG) is mainly achieved at the cost of its economic benefits. As such, this study proposes a coordinated control strategy with frequency modulated inertia layered optimization while considering the inertia response of DFIG direct current (DC) side capacitor. According to the disturbance size of the system, the inertia control task is dynamically assigned to the DFIG DC capacitor and speed inertia control module to reduce the startup times of speed control and improve the operation economy. On this basis, we propose a dynamic recovery of DC capacitor voltage based on State of charge (SOC) self-recovery to solve the problem of voltage clamping after the inertia response of DFIG DC capacitor at its stable operating boundary and thus cannot participate in subsequent inertia control. Aiming at the frequency secondary disturbance caused by DFIG speed recovery, a variable coefficient droop control method based on logistic regression function is proposed to realize the dynamic ordered recovery of DFIG speed. Simulation results show that, compared with the traditional synchronous control with the simulation time sequence of 280 s, the proposed timing optimization coordinated control strategy reduces the rotor start times by 12 times, and the wind energy capture increases by 3.6%.

Study on Stratified Settlement and Weak Reflectivity Fiber Grating Monitoring of Shield Tunnel Crossing Composite Strata

This paper proposes a set of field test technology system for layered settlement of composite strata based on weak reflectivity fiber Bragg grating sensing technology based on the shield project of “Keyuan Station ~ Shenzhen University Station” section of Shenzhen Metro Line 13, and through the comparison and verification of three-dimensional numerical simulation and field monitoring, the law and distribution characteristics of disturbance settlement of ground surface and overlying strata during shield tunneling are systematically analyzed, and the vertical and horizontal zoning (layer) system for the spatial and temporal evolution of layered settlement of composite strata during shield tunneling is constructed. On this basis, the targeted settlement control technical measures and recommendations are proposed. The findings show that the weak reflectivity fiber grating sensing technology can better perceive the evolution law and distribution characteristics of vertical and horizontal settlement of composite strata caused by shield tunneling, which is in good agreement with the numerical simulation results, and has the advantages of automation and high precision, it can be used as a supplement and alternative method for traditional measurement methods. The stratum deformation is small and layered settlement is not obvious in shield approaching stage (−5D~0), after shield crossing and shield tail falling (0~3D), the stratum is the longitudinal main deformation zone of shield tunneling disturbance, and the influence range of the whole tunneling disturbance is about (−1D~3D). Meanwhile, according to the influence degree of shield tunneling disturbance, the overlying strata of the tunnel can be divided into main disturbance layer and secondary disturbance layer, and the main disturbance layer is located in the range of 0.5D above the tunnel. In addition, based on the different stages of shield tunneling and the vertical and horizontal zoning (layers) of existing structures such as buildings (structures), the settlement control measures and suggestions are proposed. The research results demonstrate the feasibility of weak reflectivity fiber grating for distributed and continuous strata monitoring. It has important guiding value for improving the understanding of settlement law produced from shield construction in composite strata and analyzing and predicting potential risks resulting from shield construction. It also provides reference value for future subway design and construction.

Cerebrospinal Fluid Concentrations of Neurotransmitters in a Greek Pediatric Reference Population.

Biogenic amines and pterins analysis in cerebrospinal fluid (CSF) are reliable biomarkers for the diagnosis of inherited disorders of monoamine neurotransmitters. The objectives of this study were the establishment of reference values of CSF biogenic amine metabolites in a cohort of Greek children, the detection of primary defects of biogenic amine metabolism, and the assessment of biogenic amine metabolites in children with different neurological disorders. CSF biogenic amine metabolites and pterins (biopterin and neopterin) were analyzed using high-performance liquid chromatography with electrochemical and fluorescence detection. Three hundred sixty-three samples were analyzed: 60 infants and children with no history of neurological disorder, 6 with inherited disorders of monoamine neurotransmitters, and 297 with diverse neurological disorders. Reference values were stratified into six age groups. A strong correlation between homovanillic acid (HVA) and 5-hydroxyindoleacetic acid (5HIAA) levels with age was detected (p < 0.001). Two patients were diagnosed with a defect of the biogenic amine synthetic pathway and three with a defect of tetrahydrobiopterin cofactor production. HVA and 5HIAA abnormalities were detected within different groups of neurological disorders, but none followed a specific pattern of HVA and 5HIAA abnormalities. In the current study, Greek reference values of biogenic amines and pterins in CSF are presented. Five new patients with inherited monoamine neurotransmitter disorders are described. Nonspecific secondary biogenic amine disturbances can be seen in patients with different neurological disorders.

Long-term monitoring of Mount St. Helens micrometeorology.

The 1980 volcanic eruption of Mount St. Helens had profound impacts on the geology, hydrology, and ecology of its surrounding landscapes. Consequently, the event provided a unique opportunity to study ecological change over time in relation to abiotic factors. To better assess the role localized environmental conditions play in these larger processes, we have monitored micrometeorological conditions across six disturbance zones on Mount St. Helens created by the eruption. We deployed 823 environmental sensors at 191 sites from 1997 to 2022 to measure the temperature and relative humidity of aquatic (temperature only) and terrestrial habitats in these areas, collecting over 4.2 million measurements in total. Measurements were typically recorded every 30 min from late spring through mid-fall, with the exception being Spirit Lake, where temperatures have been measured hourly on a year-round basis since 2002. These data have been used to address two broad research questions: (1) how small-scale environmental conditions influence patterns of survivorship and/or establishment on Mount St. Helens post-eruption for a range of organisms, including plants, small mammals, birds, amphibians, arthropods, fish, and other aquatic biota, and (2) to quantify and compare these environmental conditions across different disturbance zones, which vary in disturbance type, intensity, and history of post-eruption secondary disturbances. Due to the repeatability of these measurements over many years, these data lend themselves to exploring the relationship between forest succession and microclimate, especially with respect to forest-dwelling organisms whose spread and demography are sensitive to temperature and relative humidity. In addition, this dataset could be used to investigate additional questions related to early succession, disturbance ecology, climate change, or volcano ecology. This dataset is available in the R data package MSHMicroMetR, which also includes an R Shiny data visualization and exploration tool. There is no copyright on the data; please cite this data paper Ecology when using these data.

25, 50 and 75 years ago

25, 50 and 75 years ago

A New Proposal Generalized Predictive Control Algorithm With Polynomial Reference Tracking Applied for Sodium Fast Reactors

This paper proposes a generalized predictive control (GPC) with constraints and orthonormal Laguerre functions using the simplified model of the primary system (reactor core and intermediate heat exchanger (IHX)) of a prototypical sodium fast reactor (SFR). This paper develops a multiple-input multiple-output (MIMO) GPC with input constraints able to track polynomial references of any degree applied in coolant temperature difference across the core and fractional power. The manipulated variables of the GPC-SFR are the reactivity and the sodium flow rate of the primary and secondary pipes. Moreover, orthonormal Laguerre functions and step down condition number techniques were also applied to avoid the numerical ill-conditioning issue in quadratic programming of large systems. Thus, a GPC type-2 was designed to control fractional power, coolant temperature difference across the core and sodium tank temperature of the SFR primary system when temperature references change according to a linear ramp after reaching their steady-state operation, sustaining 100% power operation on the reactor. In order to analyze the load tracking capability of the GPC-SFR type-2, the load following from 100% fractional power (FP) to 60% FP at 0.8% FP/min rate is simulated. Constraints on the rate of coolant temperature difference across the core and reactivity were applied for the design safety. For comparison criteria, this paper compares the GPC-SFR type-2 with the GPC-SFR type-1, i.e, standard model predictive control (MPC), to verify the viability and superior performance of the proposal regarding: (a) ramp-tracking capability of temperature and load; (b) the rejections of a reactivity disturbance of -1 cent and a secondary sodium inlet temperature disturbance of +10°F; and (c) a simulation with uncertainty in reactor design. The simulations show that the GPC-SFR type-2 overcome the GPC-SFR type-1 robustness and performance.

Incidental findings involving the temporomandibular joint on computed tomography and magnetic resonance imaging.

The temporomandibular joint (TMJ) is frequently imaged in head and neck computed tomography (CT) and magnetic resonance imaging (MRI) studies. Depending on the indication for the study, an abnormality of the TMJ may be an incidental finding. These findings encompass both intra- and extra-articular disorders. They may also be related to local, regional or systemic conditions. Familiarity with these findings along with pertinent clinical information helps narrow the list of differential diagnoses. While definitive diagnosis may not be immediately apparent, a systematic approach contributes to improved discussions between clinicians and radiologists and better patient management.

Cascade PID Control Systems Based on DNA Strand Displacement With Application in Polarization of Tumor-Associated Macrophages

Disturbances are widespread in biochemical systems. Nowadays, prevalent single-loop control strategies only take external disturbances into account. However, internal perturbations that threaten the stability of biochemical systems are invariably ignored. In this paper, a DNA strand displacement (DSD)-based cascade PID control system is designed. In addition to traditionally realizing the tracking of reference input and the attenuation of primary disturbance, the presented control approach also innovatively completes the rejection of secondary disturbance. Specifically, the dynamics of the reference input signal are first governed by a first-order low-pass filter integrated with cascade PID control systems, which efficiently avoids the excessive response of the cascaded primary and secondary controllers to the reference signal. Then, cascade PID controllers and second-order time-delay plants are constructed by utilizing the chemical reaction network (CRN) and the DSD. In terms of secondary perturbation suppression, the obtained control scheme significantly outperforms the single-loop PID control scheme with a smaller overshoot and faster settling time. Finally, the DSD-based cascade PID control method is applied to regulate gene expressions of interferon regulatory factor 4 (IRF4) and interferon regulatory factor 5 (IRF5) that affect the polarization of tumor-associated macrophages (TAMs). Compared with the single-loop PID control strategy, the control strategy exhibits a better inhibitory effect on IRF5 gene overexpression (internal disturbance) and TAMs endogenous gene expression (external disturbance).

PARAMETERS OF CENTRAL AND INTRACARDIAC HAEMODYNAMICS IN WOMEN WITH THYROID HYPERPLASIA AND ACALCULOUS CHOLECYSTITIS.

Aim: The study aimed to investigate some parameters of functional status of central and intracardiac haemodynamics in women with thyroid hyperplasia and acalculous cholecystitis. Materials and Methods: Functional changes of haemodynamic status in women with thyroid hyperplasia and acalculous cholecystitis were investigated. All data are obtained through general and special clinical methods, standard and special laboratory methods of examination, physiological, biochemical and statistical methods. Parameters of central and intracardiac haemodynamics have been recorded by the method of two-dimensional M-mode echocardiography in the echo chamber "Toshiba-140" (Japan) at the resting state. Results: An increase in heart rate (by 45.6%) was observed in patients, which led to decreased duration of cardiac cycle and ejection time. Statistically significant (p<0.05, 11.7% on average) increase in total peripheral vascular resistance was indicated. Dynamics of changes of parameters of central and intracardiac haemodynamics indicates different parallel existing pathways of secondary disturbances in the part of cardiovascular system. A significant increase in peripheral vascular resistance associated with decreased elasticity (increased vascular rigidity) of the arteries is the element of concentric type of left ventricular hypertrophy. The increase in volume in the absence of vasospastic reactions and increasing venous tone is an element of eccentric hypertrophy. Conclusions: It is possible to talk about the presence of systolic dysfunction in patients, which, however, is predominantly of functional character. The revealed specific changes in homeostatic haemodynamic characteristics in the women's body with thyroid hyperplasia and acalculous cholecystitis require the development of new, more effective and preferably drug-free (due to liver pathology and detoxification dysfunction) approaches to medical treatment of such patients.

Drug Repositioning Applied to Cardiovascular Disease in Mucopolysaccharidosis.

Mucopolysaccharidoses (MPS) are genetic metabolic diseases characterized by defects in the activity of lysosomal hydrolases. In MPS, secondary cell disturbance affects pathways related to cardiovascular disorders. Hence, the study aimed to identify MPS-related drugs targeting cardiovascular disease and select a list of drugs for repositioning. We obtained a list of differentially expressed genes and pathways. To identify drug perturbation-driven gene expression and drug pathways interactions, we used the CMAP and LINCS databases. For molecular docking, we used the DockThor web server. Our results suggest that pirfenidone and colchicine are promising drugs to treat cardiovascular disease in MPS patients. We also provide a brief description of good practices for the repositioning analysis. Furthermore, the list of drugs and related MPS-enriched genes could be helpful to new treatments and considered for pathophysiological studies.

Discrete element analysis of the effect of manual tamping operation on the mechanical properties of ballast bed

At present, the theoretical analysis of manual tamping of ballast track has not been systematically carried out. The daily maintenance and repair is mainly based on experience. This paper uses the DEM-MBD co-simulation method to establish the ballast bed-sleeper-tamping machine model, simulates the manual tamping process under specific working conditions, and analyzes the influence of manual tamping on the movement trend, the compactness and the contact state of ballast. The results show that: a) The effect of filling the instantaneous “gap” at the bottom of the sleeper is mainly realized in the stage of inserting, b) The stage of withdrawing from the ballast bed will not cause secondary disturbance to the ballast bed area at the bottom of the sleeper, c) The compactness of the ballast bed in the shallow area at the bottom of the sleeper is improved after tamping, d) The bearing capacity of the ballast bed is guaranteed, e) The difference of contact state between ballast is significantly reduced after tamping and finally, f) The load transmission path inside the ballast bed can be improved after tamping.

The dynamics of cylinder-wake/boundary-layer interaction revealed by turbulent transports

The flow past a cylinder near a plane wall for small gap ratios (G/D=0.1, 0.3, and 0.9) and fixed ReD = 1000 is numerically studied. The fundamental flow features are characterized by the instantaneous and mean fields. Then, the dynamics of cylinder-wake/boundary-layer interaction are revealed by the turbulent momentum transport and kinetic energy production. The turbulent fluctuations caused by the secondary vortex (SV) (at G/D=0.3, 0.9) and the novel tertiary vortex (TV) (at G/D=0.9) can be observed in the distributions of Reynolds stresses. For G/D=0.1 and G/D=0.3, the wake/boundary-layer interaction is dominated by ejection and sweep events, which are related to the generation of the hairpin vortex. These two bursting events lead to the momentum transport between the high- and low-speed sides. For G/D=0.9, the ejection event is not found in the interaction region because the head of the hairpin vortex is entrained into the wake. The upper roller (RU) helps to transport high-momentum fluid toward the wall in this case, although it does not take part in the interaction directly. The shedding of RU, the lower roller (RL), SV (at G/D=0.3 and 0.9), and KH (Kelvin–Helmholtz) vortex (at G/D=0.1) and the generation of the hairpin vortex are crucial to turbulent kinetic energy (TKE) production. The RU, KH vortex, and SV transfer ⟨u′u′⟩ out to ⟨v′v′⟩ and ⟨w′w′⟩ resulting redistribution of the TKE. While RL, surviving for a shorter time, transfers ⟨v′v′⟩ out to ⟨u′u′⟩ and ⟨w′w′⟩, helping explain why it disappears quickly, TV only transfers out ⟨v′v′⟩ out to ⟨u′u′⟩, and its TKE comes from other terms rather than the production term. The redistribution of TKE due to the generation of the hairpin vortex can result in the slower growth rate of the secondary disturbance growth stage, promoting the wall boundary layer transition.

Evaluating Spatiotemporal Patterns of Post-Eruption Vegetation Recovery at Unzen Volcano, Japan, from Landsat Time Series

Quantifying vegetation responses after natural disasters helps clarify complex relationships between vegetation and surface processes such as soil erosion. The heterogenous post-disaster landscape offers a naturally stratified environment for this study. Existing research tends to be frequently monitored but small-scale or sporadically monitored but large-scale. The availability of high-quality and free satellite imagery bridges this gap by offering continuous, longer-term observations at the landscape scale. Here we take advantage of a dense Landsat time series to investigate landscape-scale vegetation response rates and factors at Unzen volcano, Japan. We do this by first investigating differences between two popular vegetation indices—The Normalized Difference Vegetation Index (NDVI) and the Normalized Burn Ratio (NBR), when applied to recovery studies. We then apply pixel-wise regressions to quantify spatio-temporal vegetation response and regression tree analyses to investigate drivers of recovery. Our findings showed that simple linear-log functions best model recovery rates reflecting primary succession trajectories caused by extreme disturbance and damage. Regression tree analyses showed that despite secondary disturbances, vegetation recovery in both the short and long-term is still dominated by eruption disturbance type and elevation. Finally, compared to NDVI, NBR is a better indicator of structural vegetation regrowth for the early years of revegetation.

Distributed DETMs-based internal collision avoidance control for UAV formation with lumped disturbances

This work focuses on the internal collision avoidance control for unmanned aerial vehicle (UAV) formation based on distributed dynamic event-triggered mechanisms (DETMs) and composite disturbance observers. To decrease the transmission rate of the redundant data and alleviate the communication network burden, a method of designing distributed event-triggered mechanisms with dynamic triggering threshold functions is proposed, which are related to tracking errors, triggering errors and consistency errors. By taking the lumped disturbances into account, which include the primary disturbance generated by exogenous system and the secondary disturbance effects from adjacent UAVs, a composite disturbance observer is constructed for each UAV to counteract the negative effects of the unknown disturbances. Moreover, by referring to the prescribed performance control method, a consensus controller, which can avoid the internal collision among the multiple UAVs, is presented for each UAV to achieve the control target. The stability of the closed-loop system can be guaranteed by using the Lyapunov stability theory, along with the gains of controller and observers being represented in explicit forms. Finally, a simulation example regarding six UAVs testifies the availability of the proposed control strategy.

β-Glucosidases as dominant dose-dependent regulators of Oryza sativa L. in response to typical organic pollutant exposures

Understanding the metabolic defense and compensation to maintain homeostasis is crucial for assessing the potential health risk of organic pollutants in crops. Currently, limited understanding is available regarding the targeted metabolic pathways and response mechanism under contaminant stress. This study showed that ciprofloxacin (CIP) at the environmental concentrations (1, 5, 25, 50 mg/L) did not significantly inhibit growth or cause severe oxidative damage to rice (Oryza sativa L.). Instead, the increment in CIP concentration induced a series of sequential metabolic disorders, which were characterized predominantly by primary and secondary metabolic disturbances, including phenylpropanoid biosynthesis, the carbohydrate, lipid and amino acid metabolism. After CIP in vivo exceeded a certain threshold level (>0.29 mg/g dry weight), β-glucosidases (BGLUs) mediated the transition from the activation of the genes related to phenylpropanoid biosynthesis to the inhibition of the genes related to carbohydrate metabolism in rice. In particular, starch and sucrose metabolism showed the most profound perturbation stressed by environmental concentrations of CIP (5 mg/L) and other tested organic pollutants (10 μg/L of tricyclazole, thiamethoxam, polybrominated diphenyl ethers, and polychlorinated biphenyls). Besides, the key genes encoding endoglucanase and BGLU were significantly downregulated (|log2FC| > 3.0) under 100 μg/L of other tested organic pollutants, supporting the transition from the activation of secondary defense metabolism to the disruption of primary energy metabolism. Thus, in addition to bioaccumulation, changes in BGLU activity and starch and sucrose metabolism can reflect the potential adverse effects of pollutants on rice. This study explained the stepwise metabolic and transcriptional responses of rice to organic pollutants, which provided a new reference for the comprehensive evaluation of their environmental risks.

Effects of tetracycline on the secondary metabolites and nutritional value of oilseed rape (Brassica napus L.).

Secondary metabolism, which helps a plant cope with external stress, is sensitive to environmental changes and plays a prominent role in maintaining plant health. However, few studies of the effects of tetracycline on the relationships between secondary metabolism and plant stress responses have been performed. Here, secondary metabolism, nutritional value, and oxidative stress responses in oilseed rape (Brassica napus L.) exposed to tetracycline for 14days were investigated. Tetracycline inhibited growth and biomass accumulation and decreased the chlorophyll content. The sinapine, phenol, and flavonoid contents were 118.46%, 99.67%, and 93.07% higher, respectively, but the carotenoid content was 76.47% lower in plants exposed to 8mg/L tetracycline than the control plants. Tetracycline affected the nutritional value of oilseed rape. Tetracycline decreased the dietary fiber, soluble sugar contents, and microelement (Fe, Mn, and Zn) contents. The antioxidant system also responded strongly to tetracycline. The catalase and peroxidase activities were increased and the superoxide dismutase activity was decreased by tetracycline. Tetracycline caused oxidative damage and secondary metabolite disturbances and adversely affected oilseed rape growth and quality. The results provide a new perspective on the effects of tetracycline on plants in relation to secondary metabolites and improve our understanding involved in the toxicity of tetracycline.

P408 CERTIFICATION FOR COMPETITIVE SPORTS ACTIVITY IN A TEENAGER WITH WPW BY VIA INTRAHYSSIAN ACCESSORY PATHWAY

Abstract The case of a 12–year–old male, height 160 cm, weight 46 kg, who practices water polo at a competitive level is reported. Negative family history of cardiovascular pathologies, general and cardiovascular physical examination within the limits of normality. On the electrocardiographic trace (ECG) presence of delta wave from ventricular pre–excitation from intrahyssian accessory pathway (Fig. 1). Echocardiography + color Doppler was normal. The subject underwent a cardiopulmonary stress test with an incremental ramp protocol and steps of 20 watts / min. Shutdown at 190 watts for muscle exhaustion with peak oxygen consumption (VO2) = 43.9 mL / Kg / min, Heart rate = 197 beats / minute, BP = 210/70 mmHg, VE / VCO2 slope = 27.6. Normal course of the cronotropic and pressure curve. The ventricular pre–excitation delta wave persisted for the entire duration of the test and in recovery (Fig. 2, Fig. 3). Secondary disturbances of ventricular repolarization characterized by ST segment sub–leveling and negative T wave appeared at high load and persisted in the first minutes of recovery, delta VO2 / delta WR = 12. Given the non–disappearance of the delta wave from ventricular pre–excitation during the maximal stress test, the subject was sent to an electrophysiological study and subsequent ablation of the accessory pathway. The electrophysiological study was negative for inducibility of atrial fibrillation (AF) and ventricular arrhythmias. Safe ablation was impossible given the intrahyssian position of the accessory pathway. Considering the negativity of the electrophysiological study due to non inducibility of supraventricular and ventricular arrhythmias, eligibility for competitive sports was granted.

Case Study regarding the Stress Distribution and Microseismic Laws of Coal and Rock Underlying the Residual Coal Pillar

Abstract The stress distribution characteristics, stress gradient evolution, and focal mechanism of microseism (MS) events during mining of working face 103_ (lower) 07 under an overlying residual coal pillar were investigated. Numerical simulations and MS observations were utilized. The coupling relationship between the stress gradient and MS activity was also analysed, which indicated the correlation between the fracture of coal/rock and stress gradient. In addition, the secondary disturbance of the coal mining underlying a fractured hard-thick roof is discussed. The following four points were addressed: (1) the high stress initially concentrated under the edge of the overlying residual coal pillar, and its contribution to both the local coal and rock fracture and the significant change in the stress gradient; (2) the deformation and fracture first occurred in coal and rock underlying the edge of the residual pillar. The stress concentration gradually transferred to the interior of the pillars and was accompanied by the failure of coal and rock; (3) a high correlation between the deformation and fracture of coal/rock and the stress gradient was observed. The fractures under the pillars principally appeared in the high-stress gradient area; (4) the disturbance caused by mining of the underlying working face may cause instability of the high-level fractured roof, accompanied by high-energy MS.

Wall-cooling effects on secondary instabilities of Mack mode disturbances at Mach 6

In hypersonic boundary layers, Mack modes play a crucial role in flow instability, whose secondary instability is a hot research topic. Since hypersonic flight vehicles will probably work under high-stagnation temperature conditions, which significantly affect the aerodynamic heating calculation and aero-thermal protection design of hypersonic vehicles, it is necessary to compare the primary and secondary instabilities in high-stagnation temperature boundary layers and that in the Boeing/AFOSR Mach 6 quiet tunnel (BAM6QT). Herein, wall-cooling is adopted in order not to consider chemical reactions. With the same freestream temperature of 100 K, two Mach 6 boundary layers with the wall temperature of 20 and 600 K, corresponding to the cooled wall condition and the quiet wind tunnel condition, respectively, are chosen to conduct the linear/non-linear stability and the secondary instability analysis. Our results show that the most dangerous Mack mode originates from a fast discrete mode in the present cooled-wall flow and the most dangerous Mack mode is born from the slow discrete modes in BAM6QT boundary layers. Furthermore, when the primary amplitude of Mack mode disturbances is large, the fundamental resonance always dominates the secondary instability, resulting in steady streaky structures that have the largest amplitude in the spectrum. In addition, the present results point out that the distribution of the eigenfunctions of the fundamental modes and subharmonic modes are significantly different under various wall-temperatures. What is more, different ratios of wall temperature to incoming flow temperature have changed the spanwise wave-angle of the secondary disturbances.