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Trace amine-associated receptor 1 (TAAR1) is an intracellular expressed G-protein-coupled receptor that is widely expressed in major dopaminergic areas and plays a crucial role in modulation of central dopaminergic neurotransmission and function. Pharmacological studies have clarified the roles of dopamine D1 receptor (D1R) in the medial prefrontal cortex (mPFC) in cognitive function and social behaviors, and chronic stress can inhibit D1R expression due to its susceptibility. Recently, we identified TAAR1 in the mPFC as a potential target for treating chronic stress-induced cognitive and social dysfunction, but whether D1R is involved in mediating the effects of TAAR1 agonist remains unclear. Combined genomics and transcriptomic studies revealed downregulation of D1R in the mPFC of TAAR1−/−mice. Molecular dynamics simulation showed that hydrogen bond, salt bridge, and Pi–Pi stacking interactions were formed between TAAR1 and D1R indicating a stable TAAR1–D1R complex structure. Using pharmacological interventions, we found that D1R antagonist disrupted therapeutic effect of TAAR1 partial agonist RO5263397 on stress-related cognitive and social dysfunction. Knockout TAAR1 in D1-type dopamine receptor-expressing neurons reproduced adverse effects of chronic stress, and TAAR1 conditional knockout in the mPFC led to similar deficits, along with downregulation of D1R expression, all of these effects were ameliorated by viral overexpression of D1R in the mPFC, suggesting the functional interaction between TAAR1 and D1R. Collectively, our data elucidate the possible molecular mechanism that D1R in the mPFC mediates the effects of TAAR1 activation on chronic stress-induced cognitive and social deficits.

The rebound dynamics of double droplets impacting an inclined superhydrophobic surface decorated with macro-ridges are investigated via lattice Boltzmann method (LBM) simulations. Four rebound regions are identified, that is, the no-coalescence-rebound (NCR), the partial-coalescence-rebound of the middle part bounces first (PCR-M), and the side part bounces first (PCR-S), as well as the complete-coalescence-rebound (CCR). The occurrence of the rebound regions strongly depends on the droplet arrangement, the center-to-center distance of the droplets, and the Weber number. Furthermore, the contact time is closely related to the rebound regions. The PCR-M region can significantly reduce the contact time because the energy dissipation in this region may decrease which can promote the rebound dynamic. Intriguingly, the contact time is also affected by the droplet arrangement; i.e., droplets arranged parallel to the ridge dramatically shorten the contact time since this arrangement increases the asymmetry of the liquid film. Therefore, for multidrop impact, the contact time can be effectively manipulated by changing the rebound region and the droplet arrangement. This work focuses on elucidating the wetting behaviors, rebound regions, and contact time of the multiple-droplet impacting an inclined superhydrophobic surface decorated with macro-ridges.

Muon imaging technology, as an emerging detection method, is widely used in various fields. Muons can be classified into cosmic ray muons and accelerator muons based on their origins. Cosmic ray muons stand out for wide energy range, strong penetrating power and no artificial radiation. These characteristics make cosmic ray muon imaging technology adept at achieving nondestructive imaging of target objects. Presently, the commonly used imaging methods include scattering and transmission imaging technologies that leverage muon information for imaging. Additionally, muon and muonic secondary particle coincidence imaging technology utilizes information from secondary particles generated during the interaction between muons and target objects for imaging. The accelerator muon, distinguished by its high flux, strong monochromaticity, and adjustable energy, enables rapid and multidimensional imaging of target objects at various depths. Furthermore, it facilitates the analysis of material elements through muonic X-rays. This article provides insights into the production process and physical characteristics of muons, the fundamental principles of muon imaging technology, and its diverse applications across disciplines. It also explores the current development status and emerging trends in fields such as mineral resource exploration, archaeological studies, and nuclear safety.

Bouncing dynamics of a trailing drop off-center impacting a leading drop with varying time intervals and Weber numbers are investigated experimentally. Whether the trailing drop impacts during the spreading or receding process of the leading drop is determined by the time interval. For a short time interval of 0.15 ≤ Δt* ≤ 0.66, the trailing drop impacts during the spreading of the leading drop, and the drops completely coalesce and rebound; for a large time interval of 0.66 < Δt* ≤ 2.21, the trailing drop impacts during the receding process, and the drops partially coalesce and rebound. Whether the trailing drop directly impacts the surface or the liquid film of the leading drop is determined by the Weber number. The trailing drop impacts the surface directly at moderate Weber numbers of 16.22 ≤ We≤ 45.42, while it impacts the liquid film at large Weber numbers of 45.42 < We≤ 64.88. Intriguingly, when the trailing drop impacts the surface directly or the receding liquid film, the contact time increases linearly with the time interval but independent of the Weber number; when the trailing drop impacts the spreading liquid film, the contact time suddenly increases, showing that the force of the liquid film of the leading drop inhibits the receding of the trailing drop. Finally, a theoretical model of the contact time for the drops is established, which is suitable for different impact scenarios of the successive off-center impact. This study provides a quantitative relationship to calculate the contact time of drops successively impacting a superhydrophobic surface, facilitating the design of anti-icing surfaces.

Reducing the contact time during the droplet impact on the surface is crucial for anti-icing, self-cleaning, and heat transfer optimization applications. This study aims to minimize the contact time by modifying the surface curvature to create an asymmetric impact process. Our experiments showed that the increase in Weber numbers (We) and the decrease in the ratio of surface diameter to droplet diameter (D*) intensify the asymmetry of the impact process, yielding four distinct rebound modes. Low asymmetry observes the liquid retract toward the central point (Rebound Modes 1 and 2), whereas high asymmetry yields a wing-like rebound (Rebound Modes 3 and 4). In Rebound Mode 1, increased asymmetry would lead to more extended contact due to the prolonged waiting period. Conversely, the reduction in contact time in Rebound Mode 2 occurs due to increased asymmetry with no waiting period. For Rebound Modes 3 and 4, the retraction time could be divided into three stages, generated by two liquid detachment modes from the surface. Analysis reveals that an increased asymmetry would reduce the retraction time during the first stage but prolong it during the third stage, with no significant effects on the second. Four correlations, each pertaining to a distinct impact mode, are proposed based on these analyses to describe the contact time concerning Weand D* for droplets impacting a superhydrophobic cylindrical surface.

This study investigates whether adding ridges to a superhydrophobic cylindrical surface can reduce contact times compared to those of ridged flat or cylindrical surfaces, inspired by the shortened contact time achieved by adding ridges to flat surfaces. The study focuses on studying azimuthal ridges on the cylinder through experimentation, emphasizing the impact dynamics and contact time characteristics under varying We(Weber number) and D* (dimensionless droplet diameter). Within the ultralow Weber number range (ULWR), low Weber number range (LWR), and medium Weber number range (MWR), the contact time is longer than on ridged flat surfaces. In the high Weber number range (HWR), the opposite is observed: increased inertial forces lead to the rupture of the liquid film above the ridges due to Rayleigh–Plateau instability. As a result, the primary droplet splits into two sections with curvature effects promoting its recoiling and rebounding. This study introduces a criterion, defined as C= We/D*, and finds that when Cexceeds 2.42, not only is the contact time shorter than on ridged flat or cylindrical surfaces, but it also further decreases with an increase in Weor a decrease in D*. The contact time characteristics observed in the HWR offer potential applications in areas such as anti-icing.

We investigated the microscale electrohydrodynamic (EHD) conduction pumps in a wide range of working regimes, from the saturation regime to the ohmic regime. We showed that the existing macro- and microscale theoretical models could not accurately predict the electric force of microscale EHD conduction pumps, especially for the cases of a strong diffusion effect. We clarified that the failure is caused by a rough estimate of the heterocharge layer thickness. We revised the expression of heterocharge layer thickness by considering the diffusion effect and developed a new theoretical model for the microscale EHD conduction pumps based on the revised expression of heterocharge layer thickness. The results showed that our model can accurately predict the dimensionless electric force of the microscale EHD conduction pumps even for the cases of a strong diffusion effect. Furthermore, we developed a working regime map of microscale EHD conduction pumps and found that the microscale EHD conduction pumps more easily fall into the saturation regime compared with the macroscale EHD conduction pumps due to the enhanced diffusion effect; in other words, the microscale EHD conduction pumps have a wider saturation regime. We showed that the conduction number C0could not distinguish the working regime of the microscale EHD conduction pumps because it does not take the diffusion effect into account. By employing the revised expression of heterocharge layer thickness, we proposed a new dimensionless number, C0Dto distinguish the working regimes of microscale EHD conduction pumps.

Profiting from their slippery nature, lubricant-infused porous surfaces endow with droplets excellent mobility and consequently promise remarkable heat transfer improvement for dropwise condensation. To be a four-phase wetting system, the droplet wettability configurations and the corresponding dynamic characteristics on lubricant-infused porous surfaces are closely related to many factors, such as multiple interfacial interactions, surface features, and lubricant thickness, which keeps a long-standing challenge to promulgate the underlying physics. In this work, thermodynamically theoretical analysis and three-dimensional molecular dynamics simulations with the coarse-grained water and hexane models are carried out to explore droplet wettability and mobility on lubricant-infused porous surfaces. Combined with accessible theoretical criteria, phase diagrams of droplet configurations are constructed with a comprehensive consideration of interfacial interactions, surface structures, and lubricant thickness. Subsequently, droplet sliding and coalescence dynamics are quantitatively defined under different configurations. Finally, in terms of the promotion of dropwise condensation, a non-cloaking configuration with the encapsulated state underneath the droplet is recommended to achieve high droplet mobility owing to the low viscous drag of the lubricant and the eliminated pinning effect of the contact line. On the basis of the low oil–water and water–solid interactions, a stable lubricant layer with a relatively low thickness is suggested to construct slippery surfaces.

During assembly process, the miniature part needs to be fixed in its assembly position. In some occasions where adhesive is used, the joining force is not established due to the adhesive curing process, in that case the locking of parts is required. Manual locking is difficult to meet the increasing demand for mass production. To solve this problem and realize fully automatic assembly, a novel gripper module was designed and corresponding locking method was proposed. Thanks to the functional integration, the gripper module is capable of manipulating and locking the part. This module is integrated into the assembly system and plays a crucial role in automatic assembly. The locking method for automatic assembly is based on the integration of the part picking up and the locking unit releasing. After being placed accurately at its desired position, the miniature part can be automatically locked by releasing the locking unit. The innovative structure and mechanism of the gripper module convert the spring force into the locking force of the miniature part, ensuring non-rigid locking and suitable small locking force. Locking principle, flexibility and limitations of the proposed method were clarified in detail. Moreover, an effective compensation strategy was used to achieve accurate and stable pickup of the part, which increased the reliability of the assembly process. During automatic locking, the disturbances to the part due to the eccentric load were analyzed. The effectiveness of the gripper module and proposed method was verified by experiment. Experimental results indicated that the modular system integrated with the gripper module could meet the requirements of fully automatic assembly. Manual locking is replaced by automatic locking, and workers are liberated from tedious manual operations. The improvement of automation level enables assembly equipment to be applied to mass production scenarios.

As medical facilities are usually built at urban areas, special concrete aggregates and evaluation methods are needed to optimize the design of concrete walls by balancing density, thickness, material composition, cost, and other factors. Carbon treatment rooms require a high radiation shielding requirement, as the neutron yield from carbon therapy is much higher than the neutron yield of protons. In this case study, the maximum carbon energy is 430 MeV/u and the maximum current is 0.27 nA from a hybrid particle therapy system. Hospital or facility construction should consider this requirement to design a special heavy concrete. In this work, magnetite is adopted as the major aggregate. Density is determined mainly by the major aggregate content of magnetite, and a heavy concrete test block was constructed for structural tests. The compressive strength is 35.7 MPa. The density ranges from 3.65 g/cm3to 4.14 g/cm3, and the iron mass content ranges from 53.78% to 60.38% from the 12 cored sample measurements. It was found that there is a linear relationship between density and iron content, and mixing impurities should be the major reason leading to the nonuniform element and density distribution. The effect of this nonuniformity on radiation shielding properties for a carbon treatment room is investigated by three groups of Monte Carlo simulations. Higher density dominates to reduce shielding thickness. However, a higher content of high-Z elements will weaken the shielding strength, especially at a lower dose rate threshold and vice versa. The weakened side effect of a high iron content on the shielding property is obvious at 2.5 μSv/h. Therefore, we should not blindly pursue high Z content in engineering. If the thickness is constrained to 2 m, then the density can be reduced to 3.3 g/cm3, which will save cost by reducing the magnetite composition with 50.44% iron content. If a higher density of 3.9 g/cm3with 57.65% iron content is selected for construction, then the thickness of the wall can be reduced to 174.2 cm, which will save space for equipment installation.

In this paper, the alkali sulfadiazine neodymium (NdSD) was prepared from sulfadiazine and neodymium nitrate hexahydrate under alkaline conditions, and used as a heat stabilizer on PVC. The structure of NdSD was characterized by elemental analysis and infrared spectrum. The results show that the molecular formula of NdSD is Nd (SD)2·OH·H2O. The thermal degradation process of NdSD at 25-800°C was characterized by thermogravimetric analysis. The results show that the decomposition temperature of NdSD is higher than 200°C, which is suitable for PVC thermal stabilizer. The thermal stabilizer time of PVC by NdSD was characterized by static Congo red method. The results showed that the thermal stabilizer time of PVC increased from 2.7min to 23.2 min after adding NdSD. The discoloration effect of NdSD on PVC was characterized by oven discoloration method. The results indicate that PVC samples added with NdSD show better effect than other heat stabilizers. By means of silver nitrate solution method and Fourier transform infrared spectroscopy, it was proved that sulfadiazine neodymium can absorb and react with HCl, and further proposed a possible mechanism of NdSD stabilization of PVC.

Organophosphorus magnetic molecularly imprinted polymers (OMMIPs) with high adsorption capacities (13.5–83.8 mg g–1) and good applicability were developed for efficient extraction and pre-concentration of multiple organophosphorus pesticides (OPPs) from foodstuffs. The OMMIP-based sample pretreatment coupled with low-temperature plasma ambient ionization mass spectrometry achieved rapid screening for 90 kinds of pesticides at default maximum residue limits of National Standard (GB 2763-2021) in nine types of agro-products. The OMMIP-based liquid chromatography coupled with triple quadrupole mass spectroscopy assay demonstrated rapid magneto-actuated isolation, efficient removal of matrix interference, and reduced signal suppression, resulting in a short detection time (30 min), compliant recoveries (60.1–127.5%), low detection limits (0.0001–0.073 μg g–1), and simultaneous quantification of multi-pesticides. The yolk–shell-structured OMMIPs (Fe3O4@mTiO2@MIPs) demonstrated additional benefits of excellent ultraviolet light-driven catalytic degradation activity toward OPPs, making them eco-friendly for self-cleaning regeneration and reducing laboratory pesticide discharge. This work highlights the potential of OMMIPs for high-throughput and in situ pesticide monitoring in modern large-scale agricultural markets.

Reducing the contact time of a droplet hitting a solid surface is crucial for many situations. In this work, the dynamic behavior of a low-viscosity droplet on a superhydrophobic surface, which consists of a cylindrical substrate and a macro ridge placed axially on the peak, was numerically investigated viathe lattice Boltzmann method. The focus was given to the spreading and the detaching morphology of the droplet at the Weber number We= 0.84–37.8 and the cylinder-to-droplet radius ratio R* = 0.57–5.71. The ridge is found to redistribute the droplet mass and affect the impact outcomes, as well as the contact time. For each R*, a jug rebound, a stretched rebound straddling the ridge, and a split detachment occur sequentially with the increasing We. When R* does not exceed 1.71, the contact time decreases continuously with the increase in We. With R* being taken between 1.71 and 5.14, the contact time initially reduces with Weand plateaus after Wereaches 10.3. Once R* exceeds 5.14, the split droplets may present as a bestriding shape at We> 30.3 rather than the regular jug shape with a small We. The contact time would be decreased to a second plateau in this case. In most cases, the contact time can be shortened effectively for the droplet on a ridged cylinder compared with that of a smooth cylinder.

Thermite films are typical energetic materials (EMs) and have great value in initiating explosive devices. However, research in thermite film preparation is far behind that of research in thermite powders. Electrophoretic deposition (EPD) is an emerging, rapid coating method for film fabrication, including of energetic composite films. In this work, a polytetrafluoroethylene (PTFE)/Al/CuO organic-inorganic hybrid energetic film was successfully obtained using the above method for the first time. The addition of lithocholic acid as a surfactant into the electroplating suspension enabled PTFE to be charged. The combustion and energy release were analyzed by means of a high-speed camera and differential scanning calorimetery (DSC). It was found that the combustion process and energy release of PTFE/Al/CuO were much better than that of Al/CuO. The main reason for the excellent combustion performance of the hybrid PTFE/Al/CuO system was that the oxidability of PTFE accelerated the redox reaction between Al and CuO. The prepared PTFE/Al/CuO film was also employed as ignition material to fire a B–KNO3explosive successfully, indicating considerable potential for use as an ignition material in micro-ignitors. This study sheds light on the preparation of fluoropolymer-containing organic-inorganic hybrid energetic films by one-step electrophoretic deposition.

Random vapor nucleation leads to flooding condensation with degraded heat-transfer efficiency. Since an external electric field has a significant effect on manipulating droplets’ motion, it is possible to be one of the effective methods to hinder flooding phenomena and improve the heat-transfer rate by applying the external electric field during condensation. However, the motion of nanodroplets is more sensitive to the electric field owing to the scale effect on the nanoscale. The effect of the electric field on growth has not explicitly been comprehended. This work studied the condensation processes on a nanodimpled surface under an electric field with various strengths and directions. The results showed that condensed droplets’ growth under the electric field depends on the competition between the electric field force and solid–liquid interactions. Increased vertical electric field strength, the higher torsion by the electric field hindered the motion of vapor, decreased the collision frequency for water molecules with the cooled surface, and elongated the cluster when the electric field force dominates, thus deteriorating the condensation performance. While applying the horizontal electric field, the greater electric field strength leads to better condensation performance by the larger contacting area for heat exchange. A wetting transition induced by the electric field was observed when the electric field strength increased to a certain extent (E> 5.2 × 108V/m in this study). When the V-shaped surface replaced the dimpled surface as the condensed substrate, the same wetting transition phenomena occurred under a more significant horizontal electric field strength, showing that this method is universal. Besides, different electric field frequencies influenced both the growth and the nucleation, thus exhibiting various condensation performances.

Diuron [DU; 3-(3,4-dichlorophenyl)-1,1-dimethylurea], a widely used herbicide for weed control, arouses ecological and health risks due to its environment persistence. Our findings revealed that DU at 0.125–2.0 mg L–1caused oxidative damage to rice. RNA-sequencing profiles disclosed a globally genetic expression landscape of rice under DU treatment. DU mediated downregulated gene encoding photosynthesis and biosynthesis of protein, fatty acid, and carbohydrate. Conversely, it induced the upregulation of numerous genes involved in xenobiotic metabolism, detoxification, and anti-oxidation. Furthermore, 15 DU metabolites produced by metabolic genes were identified, 7 of which include two Phase I-based and 5 Phase II-based derivatives, were reported for the first time. The changes of resistance-related phytohormones, like JA, ABA, and SA, in terms of their contents and molecular-regulated signaling pathways positively responded to DU stress. Our work provides a molecular-scale perspective on the response of rice to DU toxicity and clarifies the biotransformation and degradation fate of DU in rice crops.

SrLi2Ti6O14(SLTO) coated with different amount of ZrO2was successfully prepared. The as-obtained composites are stacked by a series of particles with a pure phase structure and a good crystallinity. Furthermore, ZrO2coating not only enhances the structural stability of the materials but also facilitates the diffusion of lithium through the SEI film. As a result, the redox polarization was reduced, and the reversibility of the electrochemical reaction was enhanced. Particularly, SLTO-ZrO2-2 sample delivers a high initial lithiation capacity of 283.6 mA h g−1, and the values maintain at 251.7, 228.0, 207.4, 175.3, and 147.7 mA h g−1at the current densities of 0.13, 0.26, 0.54, 1.31, and 2.62 A g−1, respectively. Our experiment also confirmed that SLTO materials coated with ZrO2are suitable for high power density applications, and the lithiation specific energy efficiency of SLTO-ZrO2-2 is 200% as high as that of pure SLTO at a power density of 1257 W kg−1.

In this study, the wetting and dewetting behaviors of water nanodroplets containing various molecule numbers on nanopillar-arrayed surfaces in the presence or absence of an external electric field are investigated via molecular dynamics (MD) simulations, aiming to examine whether there is a scale effect. The results show that, in the absence of an electric field, nanodroplets on coexisting Cassie/Wenzel surfaces may be in the Cassie or the Wenzel state depending on their initial states, and apparent contact angles of the Cassie or Wenzel nanodroplets increase monotonously with increasing the droplet size. Energy analysis shows that on the same coexisting Cassie/Wenzel surface, when an electric field is imposed, a small nanodroplet possesses a lower energy barrier separating the Cassie state from the Wenzel state. Therefore, the small nanodroplet is easier to collapse into the Wenzel state. Moreover, the spontaneous Wenzel-to-Cassie dewetting transition is not observed for the nanodroplets after the removal of the electric field because the Wenzel state is a globally stable energetic state. With the same pillar geometry, both the wetting transition and the dewetting transition are significantly modified for liquids with higher intrinsic contact angles. The energy barrier of the wetting transition increases for both the large and small nanodroplets, meaning that the Cassie state becomes more robust. The energy curve shows that the Wenzel state of the large nanodroplet has higher energy so that the droplet can return to the Cassie state when removing the electric field. Intriguingly, although the small Wenzel nanodroplet has lower energy in the presence of the electric field, the dewetting transition still occurs. The increased solid–liquid interfacial tension when removing the electric field is responsible for this abnormal result. The wetting and dewetting transitions follow different energy pathways, leading to a hysteresis energy loop. There exists a critical water molecule number separating the unstable/stable Wenzel configurations, above which the Cassie state is energetically favorable and the dewetting transition can occur spontaneously after removing the electric field.

Tricationic ionic liquid (TIL) electrolytes have been successfully employed in supercapacitors with graphene electrodes, but the low power density of the TILs-based supercapacitors caused by strong cations–anions associations requires enhancement by adding organic solvents to the liquid. In this paper, the role of the solvents acetonitrile (ACN) and ethylene carbonate (EC) on the ion diffusion, the conductivity of the TIL [C6(mim)3](Tf2N)3, and the structures and the capacitances of the electrical double layers (EDLs) in TIL/ACN and TIL/EC electrolytes were probed by molecular dynamics (MD) simulations. The results indicate that adding organic solvents to the liquid significantly reduces interactions between ions, thereby greatly improving the ion diffusion coefficients and the conductivity of the TIL, and the maximum conductivity is found at the 0.55 M TIL/ACN electrolyte concentration. Moreover, the reduced packing of counterions and the strong expulsion of coions near charged electrodes are observed in the organic electrolytes, especially in the TIL/EC electrolyte. Further analyses on EDLs affirm that the asymmetric camel-shaped differential capacitance–voltage (C–V) curve in the pure TIL electrolyte is weakly changed by the solvent ACN or EC. Besides, the EDL capacitance in the TIL-based hybrid electrolytes is improved slightly by the organic solvents. Comparing the integral capacitances in TIL/ACN and TIL/EC with different solvent contents, it is found that reducing the solvent polarity may be more beneficial to promote the EDL capacitance. Comprehensively, in this work, the 0.55 M TIL/ACN electrolyte is the optimal choice for the high-performance supercapacitor. Hence, solvating TIL electrolytes in supercapacitors by suitable solvents can effectively enhance the power density without compromising energy density.

Shape memory effect (SME), mainly present in crystalline Ti-Ni alloys, is basically missing in metallic glasses (MGs) that lack the long-range periodic order of crystals. Here, we report experimental results of SME in annealed MGs, in which the low-energy configuration state recovery is observed by both differential scanning calorimetry and X-ray photon correlation spectroscopy. We elucidate the origin of SME in MGs under the potential energy landscape framework, i.e., after annealing, the energy of MGs enters into a deep basin and atoms are located in the low-energy configuration state. Albeit deviating from their relative stable configurations by temperature changes, atoms in the annealed MGs tend to return to the low-energy atomic configurations along certain trajectories as pre-annealing temperature is approached. These results could extend the application of MGs as functional materials by directionally manipulating their energy states via annealing and rejuvenation.

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The Mudan River Watershed, located in the northernmost region of China, is an important component of the Songhuajiang River System. The water quality of this watershed is of great importance because it is widely used for aquaculture production, hydraulic electro-generating, recreation, fishing, and irrigation. In this study, the water quality index (WQI) and principal component analysis (PCA) were employed to evaluate the Spatio-temporal variations in the surface water quality of the watershed. Ten monitoring sections were selected and monitored monthly for this study. Results indicated that the Chaihe bridge section exhibited the worst water quality with a WQI score of 32.81 due to large quantities of sewage discharge. Moreover, the water quality of the Mudan River Watershed showed seasonal variations. The WQI scores in the rainy season, nonrainy season, and icebound season were 69.38, 70.99, and 41.96, which was due to the surface water runoff in the rainy season as well as the low temperature and bacterial activity in the icebound season. Furthermore, the PCA technique revealed that permanganate index and ammonia nitrogen were the primary contaminants of this watershed regardless of the season. Therefore, it is urgent to restore the water quality of the Mudan River Watershed by adopting powerful management measures and improvement methods.