Injection Strategy in Natural Gas–Diesel Dual-Fuel Premixed Charge Compression Ignition Combustion under Low Load Conditions

Dual-fuel premixed charge compression ignition (DF-PCCI) combustion has been proven to be a viable alternative to conventional diesel combustion in heavy-duty compression ignition engines due to its low nitrogen oxides (NOx) and particulate matter (PM) emissions. When natural gas (NG) is applied to a DF-PCCI engine, its low reactivity reduces the maximum pressure rise rate under high loads. However, the NG–diesel DF-PCCI engine suffers from low combustion efficiency under low loads. In this study, an injection strategy of fuel supply (NG and diesel) in a DF-PCCI engine was investigated in order to reduce both the fuel consumption and hydrocarbon (HC) and carbon monoxide (CO) emissions under low load conditions. A variation in the NG substitution and diesel start of energizing (SOE) was found to effectively control the formation of the fuel–air mixture. A double injection strategy of diesel was implemented to adjust the local reactivity of the mixture. Retardation of the diesel pilot SOE and a low fraction of the diesel pilot injection quantity were favorable for reducing the combustion loss. The introduction of exhaust gas recirculation (EGR) improved the fuel economy and reduced the NOx and PM emissions below Euro VI regulations by retarding the combustion phasing. The combination of an NG substitution of 40%, the double injection strategy of diesel, and a moderate EGR rate effectively improved the combustion efficiency and indicated efficiency, and reduced the HC and CO emissions under low load conditions.

Problems and Strategies of China’s Natural Gas Industry

Although significant progress in China＇s natural gas industry has been made since the adoption of the ＂Eighth Five-Year Plan＂（from 1991 to 1995）, some problems still exist in the aspects of gas resources, exploitation, utilization and macromanagement, and hinder a further development of the natural gas industry. A series of strategies for solving the problems was put forward, including accurate orientation of the natural gas industry, strengthening the construction of gas transmission and distribution networks, comprehensive exploitation policies for ＂integration of up-and-downstream＂, government-supported gas-preferential policies, construction of the gas market frameworks and devoting strong effort to the new market development.

Research on the Control Strategy of Variable Nozzle Turbocharger for Natural Gas Engine

A variable nozzle turbocharger （VNT） was applied to a 2.2-liter L4 natural gas engine,and a VNT control system was designed to operate it.Based on VNT matching test results,a VNT control strategy was studied,in which VNT adjustment is carried out through pre-calibrated VNT handling rod position,combined with a closed-loop target boost pressure feedback using proportional-integral-derivative（PID） algorithm.Experimental results showed that the VNT control system presented in this thesis can lead to optimized performance of VNT,increase engine volumetric efficiency over a wide speed range,improve engine dynamic characteristics and upgrade economic performance.

NATURAL LANDSCAPES AND STRATEGIES OF REGIONAL SUSTAINABLE DEVELOPMENT IN EBINUR LAKE REGION IN XINJIANG

Changes and natural landscape Characteristics in Ebinur lake region are described in this paper. Based on analybog limiting factors to affect sustainable development in Ebinur lake region, strategies of regional protection, resource exploitation , environmetal harnessing and sustainable developmental hamessing and sustainable development in future are put forward.

Strategies for Natural Rubber Production and Development in China

The world's natural rubber output was 12. 31 million t and the consumption reached 12. 17 million t in 2015. China's natural rubber output was 0. 85 million t and the consumption reached 4. 724 million t in 2016. Southeast Asian countries are the main natural rubber producing countries,and ITRC policy affects the natural rubber prices. During 2017-2025,the supply of natural rubber in the world is expected to be abundant to meet downstream demand. Based on natural conditions for rubber planting and production costs,China's rubber production should place emphasis on developing ClassⅠrubber production area,strengthening Class Ⅱ rubber production area and adjusting Class Ⅲ rubber production area. It is recommended to build high-output rubber plantations in Class rubber production area in Xishuangbanna; choose rubber farms with good conditions in Class Ⅱ rubber production area and build high-quality rubber production base as the dedicated production raw material base for aviation rubber; expand the Southeast Asia rubber production belt for development of natural rubber industry.

THE FEATURES OF THE NATURAL RESOURCES AND THE RENOVATION STRATEGY OF POYANG LAKE

The present paper made an analysis of the features of the land, water,climatic and biological resources of Poyang Lake, the largest body of fresh water in china, whose water-covered area shows great variation between the flood and the dry seasons. It is a lake of transit water, the maximum recorded annual runoff, being 1,457× 108m3. Yet the great fluctuation of its runoff in different months and different years renders its function in storing and regulating the water of the Changjiang River limited and inopportune. On the other hand, the Poyang Lake is a high-valued district in sunshine hours, water evaporation and wind energy, it serves as a temperature moderator.Abundant in bioresources, the lake formed an integrated water ecosptem and a water-land alternated landbeach-grassy sandbar ecosystem. Finally, the author put forward the strategy of renovating poyang Lake by harnessing its water system; bringing the lake level under artificial control; harmonizing the relationship between Poyang Lake and the Changjiang River and making full use of the comprehensive advantages of the fake's resouces.

Research of Application of Passive Natural Ventilated Strategies of High-Density Urban Area

High-density development is becoming an inevitable tendency in Chinese urbanization. In this study,the application of natural ventilation in high-density urban development is discussed. Based on the domestic and foreign study on natural ventilation,indoor and outdoor natural ventilated strategies,and the application on natural ventilation in underground space development are analyzed. From the study,the relationship between passive and active ventilated technologies is interpreted into what is described to be synergistic,complementary and additive.

Characteristics,Current Status and Strategy on Exploitation of Agricultural Natural Resources in China

This paper formulated the present characteristics, current status and the problems of agricultural natural China. Measures of preservation and strategy about exploitation of agricultural natural resources were put forward, provide a scientific basis for the government to make policies .

Effect of Natural Disasters and Their Coping Strategies in the Kuakata Coastal Belt of Patuakhali Bangladesh

Bangladesh has experienced a number of severe natural disasters. Most recently, tropical storms Aila, Sidr and Mohaseen have affected the Kuakata coastal belt. These natural disasters have had substantial negative impacts on natural resources. Development of coping strategies for the protection of natural resources across this belt is significantly important. The present research is focused on the effects of tropical storms on crops, humans, fish, livestock and infrastructure. There were 99 fatalities recorded during the Sidr and Aila natural disasters. These disasters impacted 910.94 ha (Sidr) and 973.69 ha (Aila) of cropland. The total number of affected livestock and fishes such as, 18,200 fish ponds, 1209 cattle, 3324 goats, 6888 chickens, 1716 ducks, 103 buffalo and 144 sheep. After tropical cyclones of Sidr, Aila, Heavy rainstorms and Mohaseen 12,970, 17,703, 10,050 and 2500 households respectively reported some form of damage. Cattle, goat, chicken and buffalo were found more injured than other livestock due to the natural disasters of Sidr. Temperature and wind speed were both found to be statistically significant (p ≤ 0.05) with humidity. Climatic parameters trend has been increased significantly since 1979. Regular monitoring of climatic variables, preparedness activities, and coping strategies would be significantly important for this coastal communities.

FUNDAMENTAL RESEARCH IN NATURAL SCIENCE: SUPPORTING NATIONAL STRATEGY

The Central Committee of the Communist Party of China and the State Council have put forward "the strategy for revitalizing China through science and education" and decided to implement it with the turn of the century. All circles of the society and the broad masses of people i n China are unprecedentedly raising their scientific and technical awareness and so gradually reaching more and more common understanding of the role that fundamental research in natural science has been playing as a cornerstone in the implementation of "the strategy of revitalizing China through science and education".

Study on the Value and Sustainable Development of World Natural Heritage——A Case Study of Wulong Karst in Chongqing City, China

Unique natural landscapes of Wulong Karst were introduced and compared with other famous karst regions inscribed as the in World Natural Heritage, landscape features and significant geoscience research value of Wulong Karst was analyzed. Problems of Wulong Karst in Chongqing as the World Natural Heritage were proposed, and factors influencing its sustainable development given as: lack of professional management staff, excessive development, frequent geologic hazards and human interventions. Corresponding protective measures were given on the basis of research and investigation, sustainable development and innovation stressed as well as digitalized construction of heritage and exploration of high-end tourist products to promote the sustainable development of world heritage.

Research progress and challenges of natural gas hydrate resource evaluation in the South China Sea

As an efficient clean energy,natural gas hydrate(NGH)has become a hot topic in recent researches.Since1990 s,China has made great achievements and progress in NGH exploration in the South China Sea(SCS),including determination of the favorable distribution areas and favorable strata thickness,identification of the dual source for accumulation,evaluation of the prospective gas contents,verification of the widespread existence,and confirmation of the technical recoverability of NGH resources.However,there are three major challenges in the NGH studies.First,all the 24 national key and major projects in the SCS focused on trial production engineering and geological engineering in the past 20 years,while 8 of the 10 international NGH research projects focused on resource potential.Second,resource evaluation methods are outdated and some parameter selection are subjective.Third,the existing resource evaluation results are low-level with a great uncertainty,and cannot be used to guide NGH exploration and production or strategic research.To improve the evaluation of NGH resources in the SCS,future researches should focus on four aspects:(1)improve the research on the criterion of the objective existence of NGH and the method of prediction and evaluation;(2)apply new theories and methods from the global NGH research;(3)boost the research on the difference and correlation of the conditions of hydrocarbon migration and accumulation in different basins;(4)innovate the theory and method of NGH resource potential evaluation.

The Prosperous Natural Gas Industry in Sichuan

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Near- and Mid-term Development of Natural Gas Market in China

Economy growth in China is expected to slow down a little during the I3th Five-Year-Plan period. So will the domestic gas demand and supply market, which may be quite different from that of the 11 th and 12th Five-Year-Plan periods. The paper summarized the state quo of gas supply and demand in the country and analyzed factors that may affect the demand and supply balance in the new period. It is proposed that there will be many uncertainties in achieving supply and demand goals of gas set for tire period, and gas glut is also very possible during the time. To deal with the problem, it is suggested that several measures be taken nationwide： improving utilization of gas in several sectors, straightening and optimizing the pricing mechanism, speeding up construction of infrastructures, implementing relevant policies and boosting up supen^ision and monitor of tire industry.

Combination strategies for first-line treatment of patients with unresectable hepatocellular carcinoma:prospect of natural products

Liver cancer stands as a significant global health concern,contributing substantially to cancer incidence and mortality,particularly in Asian countries[1].Hepatocellular carcinoma(HCC)accounts for approximately 90%of all liver cancer cases and is characterized by a high-risk profile and a generally poor prognosis[2].To address advanced HCC,systemic therapy has been recommended,leading to the approval of a range of treatment regimens in clinical practice.Traditionally,first-line therapy involved the use of multitargeted tyrosine kinase inhibitors(TKIs)such as sorafenib or lenvatinib,while cabozantinib,ramucirumab.

Introducing Translation Studies:a Case Study of the Text of an Auto Company's Market Strategy

This paper starts with the necessity of the translation from English to Chinese and the other way around in auto industry. Then, talks about the nature of translation and translating, translation standards, translation strategies and discusses the characteristics of the texts of the auto company's strategy, translation techniques and at last make the conclusion.

Strategies for constructing seven-membered rings:Applications in natural product synthesis

The seven-membered ring motifs are found in bioactive pharmaceuticals and a wide range of natural products,including alkaloids and terpenoids,which hold significant importance in synthetic chemistry and has garnered considerable attention from both academia and industry.Despite the challenges faced in the past decade,the total synthesis of natural products incorporating the non-aromatic cycloheptane skeletons remains a compelling pursuit.Recently,numerous elegant strategies for constructing the sevenmembered ring system have been successfully developed.This review focuses on the recent advancements in this field from 2017 to April 2023,highlighting key transformations utilized to construct the non-aromatic cycloheptane core structures and serves as a valuable guide for synthetic chemists engaged in the total synthesis of natural products containing seven-membered ring motifs.

Applying Network Flow Optimization Techniques to Improve Relief Goods Transport Strategies under Emergency Situation

Given the seriously damaged emergency situation occurring after a large-scale natural disaster, a critical and important problem that needs to be solved urgently is how to distribute the necessary relief goods, such as drinking water, food, and medicine, to the damaged area and how to transport them corresponding to the actual supply and demand situation as quickly as possible. The existing infrastructure, such as traffic roads, bridges, buildings, and other facilities, may suffer from severe damage. Assuming uncertainty related with each road segment’s availability, we formulate a transshipment network flow optimization problem under various types of uncertain situations. In order to express the uncertainty regarding the availability of each road segment, we apply the Monte Carlo simulation technique to generate random networks following certain probability distribution conditions. Then, we solve the model to obtain an optimal transport strategy for the relief goods. Thus, we try to implement a necessary and desirable response strategy for managing emergency cases caused by, for example, various natural disasters. Our modeling approach was then applied to the actual road network in Sumatra Island in Indonesia in 2009, when a disastrous earthquake occurred to develop effective and efficient public policies for emergency situations.

Meta-Learning of Evolutionary Strategy for Stock Trading

Meta-learning algorithms learn about the learning process itself so it can speed up subsequent similar learning tasks with fewer data and iterations. If achieved, these benefits expand the flexibility of traditional machine learning to areas where there are small windows of time or data available. One such area is stock trading, where the relevance of data decreases as time passes, requiring fast results on fewer data points to respond to fast-changing market trends. We, to the best of our knowledge, are the first to apply meta-learning algorithms to an evolutionary strategy for stock trading to decrease learning time by using fewer iterations and to achieve higher trading profits with fewer data points. We found that our meta-learning approach to stock trading earns profits similar to a purely evolutionary algorithm. However, it only requires 50 iterations during test, versus thousands that are typically required without meta-learning, or 50% of the training data during test.