http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
- 中文 을 입력하시려면 zhongwen을 입력하시고 space를누르시면됩니다.
- 北京 을 입력하시려면 beijing을 입력하시고 space를 누르시면 됩니다.
RISS 인기검색어
- 검색키워드
- 저자 : ( Kaikai Cheng ) (검색결과 3 건)
- 무료
- 기관 내 무료
- 유료
-
Discussion of Sensitivity Factors and Dominating Variable for Design Value Method
Jitao Yao,Kaikai Cheng 대한토목학회 2017 KSCE Journal of Civil Engineering Vol.21 No.1
The partial factor method is considered to be one of the most reliable design methods. However, engineers have examined the shortcomings of the partial factor method, primarily its flexibility and generality in searching for the values of partial factors. In order to improve upon the partial factor method, the design value method has been established on the basis of probability. The design value method is more flexible, general, and represents the developing direction of the reliability design method. However, based on experience, a set of sensitivity factors αi values has been developed. The sum of squares may be greater than 1.0 as a result of conservatism. Although some researchers have revised the values of αi by using the enumeration optimization method, the results are not ideal. This paper focuses on the recommended values of sensitivity factors that are applicable to the safety design as well as the serviceability design. It will be shown that these recommended values can improve the accuracy of the reliability index and present specific ranges of relative errors. This makes it possible to establish a practical design value method based on probability. In addition, a method to determine the dominating parameter is illustrated.
-
Haiming Tang,Chao Li,Kaikai Cheng,Lihong Shi,Li Wen,Xiaoping Xiao,Yilan Xu,Weiyan Li,Ke Wang 한국미생물·생명공학회 2020 Journal of microbiology and biotechnology Vol.30 No.11
Soil physical and chemical characteristics, soil potential denitrification rates (PDR), community composition and nirK-, nirS- and nosZ-encoding denitrifiers were studied by using MiSeq sequencing, quantitative polymerase chain reaction (qPCR), and terminal restriction fragment polymorphism (T-RFLP) technologies base on short-term (5-year) tillage field experiment. The experiment included four tillage treatments: conventional tillage with crop residue incorporation (CT), rotary tillage with crop residue incorporation (RT), no-tillage with crop residue retention (NT), and rotary tillage with crop residue removed as control (RTO). The results indicated that soil organic carbon, total nitrogen and NH4 +-N contents were increased with CT, RT and NT treatments. Compared with RTO treatment, the copies number of nirK, nirS and nosZ in paddy soil with CT, RT and NT treatments were significantly increased. The principal coordinate analysis indicated that tillage management and crop residue returning management were the most and the second important factors for the change of denitrifying bacteria community, respectively. Meanwhile, this study indicated that activity and community composition of denitrifiers with CT, RT and NT treatments were increased, compared with RTO treatment. This result showed that nirK, nirS and nosZ-type denitrifiers communities in crop residue applied soil had higher species diversity compared with crop residue removed soil, and denitrifying bacteria community composition were dominated by Gammaproteobacteria, Deltaproteobacteria, and Betaproteobacteria. Therefore, it is a beneficial practice to increase soil PDR level, abundance and community composition of nitrogen-functional soil microorganism by combined application of tillage with crop residue management.
-
( Haiming Tang ),( Li Wen ),( Lihong Shi ),( Chao Li ),( Kaikai Cheng ),( Weiyan Li ),( Xiaoping Xiao ) 한국미생물생명공학회 2022 Journal of microbiology and biotechnology Vol.32 No.10
Soil autotrophic bacterial communities play a significant role in the soil carbon (C) cycle in paddy fields, but little is known about how rhizosphere soil microorganisms respond to different long-term (35 years) fertilization practices under double rice cropping ecosystems in southern China. Here, we investigated the variation characteristics of rhizosphere soil RubisCO gene cbbL in the double rice ecosystems of in southern China where such fertilization practices are used. For this experiment we set up the following fertilizer regime: without any fertilizer input as a control (CK), inorganic fertilizer (MF), straw returning (RF), and organic and inorganic fertilizer (OM). We found that abundances of cbbL, 16S rRNA genes and RubisCO activity in rhizosphere soil with OM, RF and MF treatments were significantly higher than that of CK treatment. The abundances of cbbL and 16S rRNA genes in rhizosphere soil with OM treatment were 5.46 and 3.64 times higher than that of CK treatment, respectively. Rhizosphere soil RubisCO activity with OM and RF treatments increased by 50.56 and 45.22%, compared to CK treatment. Shannon and Chao1 indices for rhizosphere soil cbbL libraries with RF and OM treatments increased by 44.28, 28.56, 29.60, and 23.13% compared to CK treatment. Rhizosphere soil cbbL sequences with MF, RF and OM treatments mainly belonged to Variovorax paradoxus, uncultured proteobacterium, Ralstonia pickettii, Thermononospora curvata, and Azoarcus sp.KH33C. Meanwhile, cbbL-carrying bacterial composition was obviously influenced by soil bulk density, rhizosphere soil dissolved organic C, soil organic C, and microbial biomass C contents. Fertilizer practices were the principal factor influencing rhizosphere soil cbbL-carrying bacterial communities. These results showed that rhizosphere soil autotrophic bacterial communities were significantly changed under conditions of different long-term fertilization practices Therefore, increasing rhizosphere soil autotrophic bacteria community with crop residue and organic manure practices was found to be beneficial for management of double rice ecosystems in southern China.
ScienceON
KISS연관 검색어 추천
이 검색어로 많이 본 자료
활용도 높은 자료
