연구논문(硏究論文) : 활엽수 낙엽의 수분저류 특성에 대한 실험적 분석

( Qiwen Li ),최형태 ( Hyungtae Choi ),이은재 ( Eun Jai Lee ),임상준 ( Sangjun Im ) 한국환경복원기술학회(구 한국환경복원녹화기술학회) 2016 한국환경복원기술학회지 Vol.19 No.2

This study purposed to examine the water retention capacity of floor litter in deciduous forests. Water holding capacity(WHC) and interception storage capacity of Alnus hirsuta Turcz. ex Rupr., Quercus acutissima, Quercus mongolica litters were experimentally estimated. Physical characteristics of litters were also obtained to understand the relationships between water-retention capacity and litter characteristics. Experiments showed that WHC increases with specific volume of litter, varying 244.4% to 416.8% of its dry mass. Interception storage have estimated with rainfall simulation experiments. Maximum interception storage (Cmax) and minimum interception storage (Cmin) of litters were 220% and 138% of dry mass in Alnus hirsuta Turcz. ex Rupr., 218% and 137% in Quercus acutissima, and 240% and 156% in Quercus mongolica. Both Cmax and Cmin increased linearly with litter mass, and the values of Cmin in broadleaf litters have also linear relation to leaf area.

Post Fire Effects on Structural and Hydrological Properties of Forest Soils

( Qiwen Li ),( Sangjun Im ),( Taehyun Kim ),( Jeman Lee ) 대한지질공학회 2019 대한지질공학회 학술발표회논문집 Vol.2019 No.2

A fire is one of the most dangerous events that lead to irreversible consequences on forest environment. All organic matters over and near the ground surface can burn in a fire. Combustion of forest fuels causes significant changes in soil structure and property. Fire-induced repellent layer plays an important role in controlling runoff and erosion processes after a fire. Therefore, an intensive survey on soil structure and hydrologic charactristics is needed to quantitatively examine the effects of fire on water movement and soil erosion. In this study, spatial and temporal patterns of soil properties were observed on forestlands in Gangwon province, affected by the 2019.04.04 fire. Soil texture, degrees of ash layer and soil water repellency were measured according to fire severity and fire type. Water Drop Penetration Time (WDPT) was implemented to measure the extent of soil water repellency for burnt soils. Through the field investigation, the results showed that soil properties changed with high heat, but the influences reached only a few centimeter near the soil surface. The extent and pattern of soil hydrophobicity have close relations to fuel types and fire intensities. Soil water repellency decreased with time, mainly due to raindrop impacts and soil sheet erosion. Acknowledgment This study was carried out with the support of ‘R&D Program for Forest Science Technology (Project No. 2017061B10-1919-AB01)’ provided by Korea Forest Service (Korea Forestry Promotion Institute)

Genetic diversity and phylogenetic analysis of porcine reproductive and respiratory syndrome virus in southern China from 2007 to 2014

Qiwen Wu,Zhili Li,Guanqun Zhang,Jianqiang Niu,Xiduo Zeng,Baoli Sun,Jingyun Ma 대한수의학회 2017 Journal of Veterinary Science Vol.18 No.3

Porcine reproductive and respiratory syndrome virus (PRRSV) has a high degree of genetic variation. In this study, we characterized the genetic variation and evolutionary relationships among circulating PRRSV strains in southern China. We analyzed 29 NSP2 strains and 150 ORF5 strains from clinical samples collected in southern China during 2007–2014. The alignment results showed that the nucleotide identity similarities of the two genes among these strains were 80.5%–99.7% and 80.9%–100%, respectively. Phylogenetic analysis based on the NSP2 gene showed that highly pathogenic (HP)-PRRSV was still the dominant virus in southern China from 2013 to 2014. Compared with reference strains CH-1a and VR-2332, the field strain 131101-GD-SHC, which shared high homology with JXA1-P170, had a novel 12 amino acid deletion at position 499-510. Phylogenetic analysis based on the ORF5 gene showed that HP-PRRSV, VR2332-like strains, and QYYZ-like strains were simultaneously circulating in southern China from 2007 to 2014, suggesting that, in recent years, the type 2 PRRSV was more diverse in southern China. In conclusion, mutations in the decoy epitope and primary neutralizing epitope could be markers of viral evolution and used to study evolutionary relationships among PRRSV strains in China.

Characterization and development of EST-SSR markers to study the genetic diversity and populations analysis of Jerusalem artichoke (Helianthus tuberosus L.)

Shipeng Yang,Qiwen Zhong,Jie Tian,Lihui Wang,Mengliang Zhao,Li Li,Xuemei Sun 한국유전학회 2018 Genes & Genomics Vol.40 No.10

In recent years, Jerusalem artichoke has received widespread attention as a novel source of sugar, biofuel, and animal feed. Currently, only few gDNA-SSRs derived from sunflower were verified in the Jerusalem artichoke; therefore, it is particularly important to develop SSR primer markers that belonged to Jerusalem artichoke resources. Using EST data to develop EST-SSR markers is simple and effective. In order to understand the general characteristics of SSR markers in Jerusalem artichoke EST sequences and accelerate the use of SSR markers in Jerusalem artichoke research. This study used 40,370 sequenced unigene fragments and MISA software to identify SSR loci. The 48 pairs of EST-SSR primers assessed for the identification of 45 varieties of Jerusalem artichoke. Cluster, genetic diversity parameters and AMOVA analysis was conducted using the genetic similarity coefficient, revealing genetic differences between 48 genetic material. A total of 1204 SSR loci were identified with 13 different types of repeats, distributed among 1020 EST sequences, of which trinucleotide repeats were the most common, accounting for 38.21% of the total SSR loci. Among the 44 repeat motifs, AG/CT, AAG/ CTT, and ATC/ATG motifs had the highest frequencies, accounting for 22.45, 14.71, and 7.84% of all motifs, respectively. From these sequences, 48 pairs of EST-SSR primers were designed, and 22 primer pairs for loci with high polymorphism were selected to analyze the genetic diversity of 45 Jerusalem artichoke germplasm sources. The results indicated that the variation range of the effective number of alleles for 22 primers ranged between 1.7502 and 4.5660. The Shannon’s information index ranged between 0.6200 and 1.6423. The variation range of PIC ranged between 0.3121 and 0.6662 with an average of 0.5184. Cluster analysis was conducted using the genetic similarity coefficient, revealing significant genetic differences between Asian and European genetic material. Cluster analysis revealed a relationship between the genotypes and geographic origins of the Jerusalem artichoke. The results of AMOVA as well as the genetic identity and genetic distance in the Jerusalem artichoke population showed that there presented certain genetic heterogeneity in Jerusalem artichoke genetic structure of 45 samples from seven different geographic populations. The Jerusalem artichoke EST-SSR marker system established in this study provides an effective molecular marker system for future research focused on Jerusalem artichoke genetic diversity and the breeding of new varieties.

Effects of a chitosan nanoparticles encapsulation on the properties of litchi polyphenols

Xingan Cheng,Qiwen Zou,Hanhui Zhang,Jianwei Zhu,Murtaza Hasan,Fangyun Dong,Xin Liu,Junjie Li,Yuehua Wu,Xiaojing Lv,Keqiang Wang,Xiangling Deng,Zhanmei Liu,Xuhong Jiang 한국식품과학회 2023 Food Science and Biotechnology Vol.32 No.13

Litchi polyphenols have very specific biological activities. Nevertheless, the low and inconsistent oral bioavailability and instability hinder the further application of litchi polyphenols in food systems. This work prepared litchi polyphenols loaded chitosan nanoparticles (LP-CSNPs) by ionic gelation method to enhance the encapsulation on the properties of litchi polyphenols. The optimum conditions of formation via single factors and the Box–Behnken design were chitosan (CS) concentration 1.065 mg/mL, sodium tripolyphosphate (TPP) concentration 0.975 mg/mL, and the mass ratios of polyphenols and CS 1:1 with encapsulation efficiency (EE%) of 45.53%. LP-CSNPs presented the nanosized range of particle size (mean 170 nm), excellent polydispersity index (PDI) (0.156 ± 0.025), and zeta potential values (+ 35.44 ± 0.59). The in vitro release in simulated gastric fluid (pH 1.2) and intestinal fluid (pH 6.8) during 100 h was 58.34% and 81.68%, respectively. LP-CSNPs could effectively improve the storage stability and had great antibacterial activity compared with unencapsulated litchi polyphenols.

Investigation of Rebar Exposure Issues of Diaphragm Wall and Influencing Factors Analysis

Liyuan Tong,Qiwen Guo,Hongbo Che,Mingfei Zhang,Huangsong Pan,Hongjiang Li 대한토목학회 2019 KSCE JOURNAL OF CIVIL ENGINEERING Vol.23 No.4

The exposure of rebar in diaphragm wall was discovered after excavation in more than 20 subway stations, along the lines 1 to 4 in Suzhou, China. Such phenomena were investigated from strata formation, hydrogeological condition, construction techniques, adjacent surcharge load and other aspects. Based on field investigation, in situ testing and numerical simulation, the disturbance of trenching operations and the main factors that affect the stability of the diaphragm wall during the trenching process are analyzed comprehensively. The results show that the deformation behavior and stability of slurry trench walls are mainly influenced by strata characteristics, adjacent surcharge loading, formation of bentonite filter cake on trench walls, pressure of a confined aquifer, height of slurry filling and slurry density. The underground water pressure in the confined aquifer of silty soil layers is considered as one of the main controlling factors, which is verified by the subsequently dewatering and trenching tests. During the construction process, the deformation and stability of the trench walls can be improved by adjusting and controlling the crucial controlling factors. Further, relevant remedial measures as well as the preventive methods during the process of constructing diaphragm walls and subsequent soil excavation are addressed.

인공강우실험에 의한 임도노면의 지표유출량 및 토양유실량 평가

유송 ( Song Eu ),( Qiwen Li ),이은재 ( Eun Jai Lee ),임상준 ( Sangjun Im ) 한국환경복원기술학회 2015 한국환경복원기술학회지 Vol.18 No.3

Unpaved forest roads are common accessways in mountain areas being used for forestry purposes. The presence of forest roads produces large volumes of surface runoff and sediment yield due to changes in soil properties and hillslope profile. Rainfall simulation experiments were conducted to estimate the impacts of above-ground vegetation and antecedent soil water condition on hydrology and sediment processes. A total of 9 small plots(1m×0.5m) were installed to represent different road surface conditions: no-vegetation(3 plots), vegetated surface(3 plots), and cleared vegetation surface(3 plots). Experiments were carried out on dry, wet, and very wet soil moisture conditions for each plot. Above ground parts of vegetation on road surface influenced significantly on surface runoff. Runoff from no-vegetation roads(39.24L) was greater than that from vegetated(25.05L), while cleared-vegetation condition is similar to no-vegetation roads(39.72L). Runoff rate responded in a similar way to runoff volume. Soil erosion was also controlled by land cover, but the magnitude is little than that of surfacerunoff. Even though slight differences among antecedent soil moisture conditions were found on both runoff and soil erosion, runoff rate and soil losses were increased in very wet condition, followed by wet condition. The experiments suggest that vegetation cover on forest road surface seems most effective way to reduce surface runoff and soil erosion during storm periods.

임목생산방법에 따른 토양교란 영향 평가

이은재 ( Eunjai Lee ),( Qiwen Li ),유송 ( Song Eu ),한상균 ( Sang-kyun Han ),임상준 ( Sangjun Im ) 한국임학회 2017 한국산림과학회지 Vol.106 No.2

중장비를 이용한 임목생산작업은 산림 내 토양교란을 유발하며, 산림토양은 토양침식에 취약한 구조를 가지게 된다. 임목생산방법 및 장비에 따라 토양교란 유형 및 토성 변화 정도는 다르게 나타난다. 따라서 이 연구에서는 국내에서 이루어지고 있는 우드그랩을 이용한 단목생산방법과 스윙야더를 이용한 전목생산방법에 따른 토양교란 영향을 평가하였다. 이를 위하여 토양교란 유형은 시각적 평가방법을 이용하여 분류하였으며, 교란 유형에 따른 토양의 물리성 변화는 토양시료캔에 의한 샘플링 방법을 이용하였다. 단목과 전목생산작업지에서 관찰된 극심한 교란(deep disturbance)과 토양답압(compacted) 유형은 각각 48%와 23%로 나타났다. 또한, 임목생산작업에 따른 토양의 물리성 변화는 중장비 차량이 통행한 곳에서 차이가 발생하였다. 반면 차량 통행과 관련 없는 토양교란 유형에서는 임목수확작업 전 · 후의 토양의 용적밀도 및 공극률은 통계적으로 차이가 없었다. 이 연구를 통해 산림 내에서 중장비의 통행으로 인하여 주로 토양 교란 및 훼손이 발생함을 알 수 있었다. Soil disturbance caused by timber harvesting is widely recognized as a potential threat to forest utilization. The degree and extent of soil disturbance is believed to vary with respect to harvesting methods and logging machines. This study has conducted to assess the degree of soil disturbance associated with ground-based cut-to-length (GC) and cable yarding with whole tree (CW) harvesting methods. Soil disturbance was classified using a visual assessment of harvest unit. The properties of soils in different disturbance levels were also evaluated to understand the influence of timber harvesting on soil structure with soil core sampling method. The deep disturbance and soil compaction were observed in sites by 48% and 23% through harvesting areas for GC and CW logging methods, respectively. The results showed that logging machine and number of machine passage had significant influences on soil bulk density and porosity. Soil disturbance types such as rutted, slash cover, and compact were influenced by equipment travel trends in a GC method.

근적외선 분광기법을 이용한 낙엽의 함수율 예측

홍석주 ( Suk-ju Hong ),( Qiwen Li ),임상준 ( Sangjun Im ),김기석 ( Ghiseok Kim ) 한국농업기계학회 2016 한국농업기계학회 학술발표논문집 Vol.21 No.2

매년 막대한 피해를 불러일으키는 대표적 산림재해인 산불은 낙엽 등의 연료의 연소를 통해 일어난다. 이 때 낙엽의 수분함량은 산불의 발화와 확산에 중요한 요소이다. 낙엽이 건조할수록 산불이 일어나기 쉬워 마른 낙엽이 쌓인 봄철에 산불의 발생이 적으며, 낙엽의 수분함량이 높은 여름에 산불의 발생이 적다. 수분은 근적외선 대역의 특정 파장을 흡수하는 성질을 가지며, 이와 관련하여 근적외선 분광기법으로 수분함량을 측정하는 연구들이 선행되어 왔다. 따라서 본 연구에서는 근적외선 분광기와 초분광 카메라로 얻은 정보를 통해 낙엽의 함수율을 예측할 수 있는 모델을 개발하고자 하였다. 굴참나무, 상수리나무, 신갈나무, 전나무 네 가지 종류의 낙엽을 침수를 통해 함수율 조건을 설정한 후, 근적외선 분광기를 이용해 근적외선 반사 스펙트럼을 얻고, 초분광카메라를 이용해 가시광선-근적외선 대역의 초분광 영상을 획득하였다. 낙엽을 드라이오븐에서 135℃로 하루 동안 건조하여 중량법으로 함수율을 측정한 후, 전처리를 거친 근적외선 스펙트럼데이터와 PLS 회귀분석을 하여 회귀모델을 구성하였다. 각 낙엽의 종류별과 활엽수군에 대하여 PLS 회귀분석을 진행하여 가장 적절한 전처리법을 거친 최적 모델들을 획득하였다. 활엽수군에 대한 최적 모델은 SNV 전처리를 거쳤으며 Calibration Rsquare 0.9623 Validation Rsquare 0.9518의 높은 적합도를 보였다. 초분광 영상은 영상처리를 통해 낙엽의 이미지를 분리한 후 한 이미지의 픽셀 당 스펙트럼 데이터의 평균을 낸 후 PLS 회귀분석을 진행하였다. 활엽수군에 대하여 최적의 모델은 전처리를 거치지 않았으며 Calibration Rsquare 0.8730 Validation Rsquare 0.6933의 결과를 얻었다.

산림유역의 계류수질 현황 및 계절적 변동 특성

남수연,임홍근,이기문,최형태,양현제,김재훈,Nam, Sooyoun,Lim, Honggeun,Li, Qiwen,Choi, Hyung Tae,Yang, Hyunje,Kim, Jaehoon 한국물환경학회 2022 한국물환경학회지 Vol.38 No.5

Seasonal variability of water quality in the upland headwater streams in ten forested catchments (37.0~209.0 ha) was examined from April to November 2021. Here, seven physicochemical parameters were analyzed including pH, electrical conductivity (EC), biochemical oxygen demand (BOD), chemical oxygen demand (COD), total nitrogen (T-N), total phosphorous (T-P), and BOD/TOC. The parameters were compared with those of lowerland rivers as middle and lower reaches within a watershed. The pH showed was low (6.4~6.9) during all the seasons, however, BOD and BOD/TOC in the fall season were 2-fold higher than in the spring and summer seasons. Based on environmental standards, the water quality level revealed that the upland headwater streams maintained the purity and cleanliness of water except for pH in the summer season. BOD/TOC of all the seasons and BOD of the fall season in the upland headwater streams were higher than that in the lowerland rivers, whereas the rest of the physicochemical parameters in the upland headwater streams were lower than that in the lowerland rivers. Additionally, the water quality level maintained the purity and cleanliness of water as "Good" in two reaches. The unique aspects of our study design enabled us to draw inferences about water quality characteristics with temporal and spatial analysis in upland headwater streams. This design will be useful for the long-term strategy of effective water quality management for integrated upland headwater streams and lowerland rivers within a watershed.