Interference Alignment with Multiple Antennas for Single Group D2D Communications

Yunpeng Li,Kyunghi Chang 한국통신학회 2015 한국통신학회 학술대회논문집 Vol.2015 No.1

Numerical Analysis of Directional Rock Blasting with Continuous-Discontinuous Element Method

Yunpeng Li,Chun Feng,Yiming Zhang 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.8

When simulating the directional blasting process, many researchers focus on the cutting and splitting effects who might pay more attention on the crushing effects when studying conventionalcut blasting. In this case, a numerical tool capable of capturing the strong discontinuity processes of quasi-brittle materials is highly preferable, where many blasting parameters should be calibrated and inputted. In this work, a hybrid finite-discrete elements method with explicit iterative procedure named Continuous-Discontinuous Elements Method (CDEM) is adopted to study the directional rock blasting processes. Landau model is used to capture the detonation effects, where the parameters are calibrated by comparing to the results provided by published literatures. We found that: i) The crack propagation mode of directional rock blasting is similar to those found in Brazilian splitting tests where the crack initiates from the midpoint of the connecting line of blast holes; ii) Compared with traditional cut blasting, the free surface has no significant influence on the blasting effect of directional cut blasting, while the spacing of the hole has great influence on the cutting effect. The index of fracture degree can be used to evaluate the blasting effect quantitatively. This work partly reveals some cracking patterns and rules of directional rock blasting, which may assist the engineers to develop improved precise blasting technologies.

Synthesis of mesoporous PrxZr1-xO2-δ solid solution with high thermal stability for catalytic soot oxidation

Hongcheng Li,Kongzhai Li,Xing Zhu,Yunpeng Du,Yonggang Wei,Kang Zhai,Hua Wang 한국공업화학회 2017 Journal of Industrial and Engineering Chemistry Vol.54 No.-

The fabrication of mesoporous PrxZr1xO2d solid solutions with different Pr/Zr molar ratios is reported in the present work. Based on a systematic investigation, the anion of Zr precursor and template species are found to play the most important roles for the formation of mesoporous structure. The triblock copolymer Pluronic F127 template helps to generate porosity in the matrix by self-assembly into micelle, while the additional Cl1 from Zr precursor can lead to the enhancement of the interaction between non-ionic micelles. The physicochemical properties of the obtained samples were studied by means of N2 sorption analysis, TEM, XRD, H2-TPR, O2-TPD and XPS technique. It is found that, compared with the nonmesoporous counterparts, the mesoporous PrxZr1xO2d solid solutions possess much higher specific surface area (139 m2 g1) and enhanced redox ability. Also, the ability to release oxygen is improved after aging at high temperature. For the catalytic soot oxidation, the fresh mesoporous Pr0.1Zr0.9O2d catalyst (calcinated at 500 C) shows high activity in a loose contact condition (T50 = 399 C). It should be highlighted that the T50 values over the three mesoporous PrxZr1xO2d samples decrease by 8–24 C after aging at 800 C for 3 h. This suggests that the mesoporous PrxZr1xO2d solid solution is an ideal candidate for catalytic application at high temperatures.

Effects of Continuous Straw Returning on Soil Functional Microorganisms and Microbial Communities

Guan Yunpeng,Wu Meikang,Che Songhao,Yuan Shuai,Yang Xue,Li Siyuan,Tian Ping,Wu Lei,Yang Meiying,Wu Zhihai 한국미생물학회 2023 The journal of microbiology Vol.61 No.1

This study examined the changes in soil enzymatic activity, microbial carbon source metabolic diversity, and straw decomposition rates in paddy fields treated with 1, 2, or 3 years of straw returning (SR1–SR3). The soil’s ability to decompose straw and cellulolytic bacteria increased with the number of treatment years (1: 31.9% vs. 2: 43.9% vs. 3: 51.9%, P < 0.05). The numbers of Azotobacter, Nitrobacteria, cellulolytic bacteria, and inorganic phosphate bacteria increased progressively with the numbers of straw returning years. Cellulolytic bacteria and inorganic phosphate bacteria were significantly positively correlated with the decomposition rate (r = 0.783 and r = 0.375, P < 0.05). Based on 16S sequencing results, straw returning improved the microbial diversity of paddy soils by increasing unclassified bacteria and keeping dominant soil microorganism populations unchanged. The relative importance of individual microbial taxa was compared using random forest models. Proteobacteria, ammoniating bacteria, and potassium dissolving bacteria contributed to peroxidase activity. The significant contributors to phosphate monoesterase were Acidobacteriota, Desulfobacterota, ammoniating bacteria, cellulolytic bacteria, and potassium-dissolving bacteria. Proteobacteria, ammoniating bacteria, cellulolytic bacteria, and potassium-dissolving bacteria contributed to urease activity. Desulfobacterota, ammoniating bacteria, cellulolytic bacteria, and potassium-dissolving bacteria contributed to the neutral invertase activity. In conclusion, soil microbial community structure and function were affected within 2 years of straw returning, which was driven by the combined effects of soil organic carbon, available nitrogen, available potassium, and pH. With elapsing straw returning years, soil properties interacted with soil microbial communities, and a healthier soil micro-ecological environment would form.

Comparative analysis of physiological traits of three Actinidia valvata Dunn genotypes during waterlogging and post-waterlogging recovery

Zhi Li,Yunpeng Zhong,Danfeng Bai,Miaomiao Lin,Xiujuan Qi,Jinbao Fang 한국원예학회 2020 Horticulture, Environment, and Biotechnology Vol.61 No.5

Kiwifruit ( Actinidia sp.) vines are poorly adapted to waterlogging stress. Actinidia valvata is more tolerant against waterloggingstress than Actinidia deliciosa , and the latter contains some common rootstocks that are frequently used in kiwifruit cultivation. Little is known about the responses of A. valvata genotypes against waterlogging stress and during post-waterloggingrecovery. Here, we compared physiological traits of three A. valvata genotypes (KR1, KR3, and KR5) during waterloggingstress and recovery. Kiwifruit vines displayed water loss, a decline in the net photosynthetic rate, and inhibited shoot elongationduring waterlogging. These three genotypes could endure long-term waterlogging owing to their unique root systemconfi gurations as well as by sustaining carbohydrate reserves in the roots. Feeder roots of KR1 vines were damaged earlierand lost water more quickly than the other genotypes. Under the same stress, KR3 formed adventitious roots more rapidly,while KR5 had an improved ability to control water loss in above-ground tissues. After reoxygenation, growth of vineswas partially recovered due to water loss control, photosynthetic recovery, and carbohydrate replenishment. KR3 and KR5recovered their growth earlier and replenished more carbohydrates than KR1 after re-aeration. During waterlogging, both therelative water content and carbohydrate levels of vines can limit the recovery effi ciency after re-aeration. Our results revealedmutual and distinct responses of diff erent A. valvata genotypes during waterlogging stress and recovery and provided moreinsight into the physiological basis of their adaptation to waterlogging stress.

Kinetin inhibits apoptosis of aging spleen cells induced by D-galactose in rats

Mengyun Li,Wu-Qing OuYang,Xiaoli Wu,Yin Zheng,Yunpeng Wei,Lei An 대한수의학회 2014 JOURNAL OF VETERINARY SCIENCE Vol.15 No.3

Kinetin (Kn) is a cytokinin growth factor that exertsseveral anti-aging and antioxidant effects on cells andorgans. To investigate the mechanism underlying apoptoticevents in aging cells induced by D-galactose (D-gal), weexamined the effect of Kn delivered via nuchalsubcutaneous injection on D-gal-induced aging andapoptosis in rats. Our results showed that interleukin (IL)-2levels and mitochondrial membrane potential (Δ Ψ m) weredecreased by Kn in aging rats while IL-6 production andapoptosis increased. In addition, the expression ofanti-apoptotic Bcl-2 was low while that of Bax was high inthe aging group. After treated with Kn, compared withaging group, there showed obvious difference in Kn groupwith elevated IL-2, proliferation index, Bcl-2, Δ Ψ m anddecreased IL-6 and Bax in splenic lymphocyte. Based onthese results, we concluded that Kn can effectively protectthe rat spleen from aging, apoptosis, and atrophy.

Epsilon-Fe₂O₃ is a novel intermediate for magnetite biosynthesis in magnetotactic bacteria

Tong Wen,Yunpeng Zhang,Yuanyuan Geng,Junquan Liu,Abdul Basit,Jiesheng Tian,Ying Li,Ji-Lun Li,Jing Ju,Wei Jiang 한국생체재료학회 2019 생체재료학회지 Vol.23 No.3

Background: Natural biological magnetite nanoparticles are widely distributed from microorganisms to humans. It is found to be very important in organisms, especially in navigation. Moreover, purified magnetite nanoparticles also have potential applications in bioengineering and biomedicine. Magnetotactic bacteria (MTB) is considered one of the most abundant species around the world which can form intracellular membrane enveloped magnetic nanoparticles, referred to as magnetosomes. To our knowledge, the biomineralization of magnetosome in MTB involves a serious of genes located on a large unstable genomic region named magnetosome island, which specially exists in MTB. The magnetite core of magnetosome formed via a Fe (III) ion intermediates, for instance, α-Fe2O3 and ferrihydrite. Though the biosynthesis of magnetosome represents a general biomineralization mechanism of biogenic magnetite, knowledge of magnetosome biosynthesis and biomineralization remains very limited. Method: Cells used in this study were cultured in a 7.5-L bioreactor, samples for intermediate capture were taken each certain time interval after the generation of magnetosome biosynthesis condition. High-resolution transmission electron microscopy were used to analyze the detailed structure of magnetosomes. The parameters of the crystal structures were obtained by Fast Fourier Transform analyses. Results: In this study, we identified a novel intermediate phase, ε-Fe2O3, during the magnetite maturation process in MTB via kinetic analysis. Unlike α-Fe2O3, which has been reported as a precursor during magnetosome biosynthesis in MTB before, ε-Fe2O3, due to its thermal instability, is a rare phase with scarce natural abundance. This finding confirmed that ε-Fe2O3 is an important novel intermediate during the biomineralization of magnetosome in MTB, and shed new light on the magnetosome biosynthesis pathway.

Gasoline Desulfurization by Catalytic Alkylation over Methanesulfonic Acid

Xiaolin Wu,Yunpeng Bai,Ying Tian,Xuan Meng,Li Shi 대한화학회 2013 Bulletin of the Korean Chemical Society Vol.34 No.10

Methanesulfonic acid (MSA) was used as catalyst to remove trace organic sulfur (thiophene) from Fluid Catalytic Cracking gasoline (FCC) via alkylation with olefins. The reactions were conducted in Erlenmeyer flask equipped with a water-bath under atmospheric pressure. The influence of the temperature, the reaction time, and the mass ration of MSA were investigated. After a 60 min reaction time at 343 K, the thiophene conversion of 98.7% was obtained with a mass ration of MSA to oil of 10%. The catalyst was reused without a reactivation treatment, and the thiophene conversion reached 92.9% at the third time. The method represents an environmentally benign route to desulfur, because MSA could easily be separated from the reaction mixture via decantation and it could be reused.

Public safety users’ priority-based energy and time-efficient device discovery scheme with contention resolution for ProSe in third generation partnership project long-term evolution-advanced systems

Kaleem, Zeeshan,Li, Yunpeng,Chang, KyungHi IET 2016 IET COMMUNICATIONS Vol.10 No.15

<P>A device-to-device (D2D) discovery scheme is key enabler for proximity-based services in third generation partnership project long-term evolution-advanced systems for public safety (PS) and general LTE scenarios. The deployment of D2D networks results in severe co-channel interference between conventional cellular users and D2D users, and faces proximity interference management challenges because of the co-existence of multiple D2D users. We propose a time and energy-efficient contention-resolving device discovery resource allocation (TEECR-DDRA) scheme that has the capability to enhance the success ratio for discovery of D2D users by reducing collisions among users. Moreover, the proposed TEECR-DDRA scheme has the ability to prioritise PS users to meet their QoS and latency requirements. Furthermore, multi-channel slotted ALOHA with energy sensing can be used to increase the probability of successful discovery of non-PS users. This ability helps to reduce the discovery time of PS users under disaster scenarios, and also reduces the energy consumption of non-PS users by minimising the number of beacon retransmissions. System-level simulations show that the proposed TEECR-DDRA scheme performs remarkably well under D2D network. Compared with the conventional random access scheme, the proposed scheme almost doubles the discovery range and significantly improves the success ratio for discovery of D2D users.</P>

Knowledge Map Analysis of Smart Tourism Research: Comparison of Chinese and English Papers

Huang, Tao,Li, Yunpeng Smart Tourism Research Center 2021 Journal of smart tourism Vol.1 No.4

Smart tourism and associated topics have been extensively discussed by scholars around the world. The goal of this study is to make available an all-inclusive database-based analysis of the longitude status of research on smart tourism. Three databases, Web of Science (WoS), Science Direct and China Knowledge Network (CNKI), were utilized to gather papers published from 2011 to 2020. The data results were analyzed and results were generated using CiteSpace. The results of Chinese and English papers were evaluated to form the conclusion of this study. The implication formed the prediction of future research trends and development suggestions.