• 대한기계학회논문집B
• /
• 제21권9호
• /
• pp.1185-1197
• /
• 1997

Three-dimensional flow within a film-cooling hole, which is normally oriented to the main flow, has been measured by using a straight five-hole probe for the blowing ratios of 1.0 and 2.0. The length-to-diameter ratio of the injection hole is fixed to be 1.0 throughout the whole experiments. The result shows that the secondary flow within the hole is strongly affected by the main flow and flow separation at the hole inlet. The higher blowing ratio provides less influence of the main flow on the injectant flow. The three-dimensional flow at the hole exit is considerably altered due to the strong interaction between the injectant and main flow. The aerodynamic loss produced inside the injection hole is mainly attributed to the inlet flow separation.

• 대한기계학회논문집
• /
• 제10권3호
• /
• pp.367-375
• /
• 1986

본 연구에서는, 주분무의 착화지연기간에 미치는 보조연료 분사시기의 영향 및 공기유동을 연소장 내에 도입시켜 분무와 공기의 혼합을 적극적으로 촉진시킴에 따라 그 후의 연소과정이 어떤 영향을 받는가에 대해서 검토했다.또 소형고속 디이 젤기관에서는 분무의 연소기간을 최대한 단축 시키지 않으면 안되므로, 보조연료 분사 에 의해 그 단축목적이 어느 정도 달성될 수 있는 가능성을 제2보에서 시사한 바 있으 나 본 연구에서 더욱 상세히 검토했다.

• 한국자동차공학회논문집
• /
• 제12권2호
• /
• pp.45-53
• /
• 2004

An experimental study was carried out to obtain the fundamental data about the effects of radicals induced injection on premixture combustion. A constant volume combustor divided to the sub-chamber and the main chamber was used. The volume of the sub-chamber is set up to occupy less than 1.5％ of that of whole combustion chamber. Radial twelve narrow passage holes are arranged between the main chamber and the sub-chamber. The products including radicals generated by spark ignition in the sub-chamber will derive the simultaneous multi-point ignition in the main chamber. While the equivalence ratio of pre-mixture in the main chamber and the sub-chamber is uniform. We have examined the effects of the sub-chamber volume, the diameter of passage hole, and the equivalence ratio on the combustion characteristics by means of burning pressure measurement and flame visualization. In the case of radical ignition method(RI), the overall turning time including the ignition delay became very short and the maximum burning pressure was slightly increased in comparison with those of the conventional spark ignition method(SI), that is, single chamber combustion without the sub-chamber. The combustible lean limit by RI method is extended to more ER=0.25 than that by SI method. Therefore the decrease of every emission including NOx and the improvement of fuel consumption is anticipated due to lean burn.

• 소성∙가공
• /
• 제20권1호
• /
• pp.5-10
• /
• 2011

The main objective of the present study is to predict the process window of injection-compression molding corresponding to the capability of an injection machine for fabricating 7 inch LGP. The open distance and volume filled after injection stage were found to be two important factors that affect critical requirements such as flow length, injection pressure and clamping force for the process. Process window for the key factors was also predicted by response surface method. As a result, predicted process window for open distance and volume filled after injection stage satisfying the critical requirement with a given injection machine was in the range of 60 ~ 75%, and 104.00 ~ 104.25%, respectively.

• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 1999년도 춘계학술대회논문집
• /
• pp.213-217
• /
• 1999

An expert system is developed for rational and efficient design of multi-component injection molding which is a fairly new manufacturing technique to produce plastic parts by injecting two or more materials sequentially using multiple injection units in a single machine into a single rotary mold. The knowledge base used in the present design system is primarily composed of two parts ; knowledge from domain expert and knowledge from CAE analysis. The present expert system has hour main modules ; general design guidelines for injection molding specific guidelines for multi-component injection molding redesign guidelines from the result of the CAE analysis and finally troubleshooting for multi-component injection molding. To show the validity of the present design methodology two shop floor design problems were tested ; design and fabrication of timing belt cover and power window's assist knob by using multi-component injection molding.

• 한국자동차공학회논문집
• /
• 제22권4호
• /
• pp.55-64
• /
• 2014

This work was investigated on pilot injection strategy of blended fuels(Diesel-DME) for combustion and emissions in a single cylinder direct injection compression ignition engine. Diesel and DME were blended by the method of weight ratio. Weight ratios for diesel and DME were 95:05 and 90:10 respectively. dSOI between main and pilot injection timing was varied. A total amount of injected fuels(single injection) was adjusted to obtain the fixed BMEP as 4.2 bar in order to compare with the fuel conditions. Also, the amount of pilot injection fuel was varied by 5%, 10% and 20% of total injection fuel. The engine was equipped with common rail and injection pressure is 700 bar at 1200 rpm. As a result, when mixing ratio increase, indicated thermal efficiency was increased in comparison with DD 100 and CO, THC and smoke were lower than DD 100. The influence of reducing NOx by pilot injection was more effective than DD 100. When pilot injection quantity increase, abrupt increase of NOx was occured at pilot injection quantity of 20%.

• 한국기계가공학회지
• /
• 제20권6호
• /
• pp.76-81
• /
• 2021

A plastic noise barrier is a structure installed to minimize noise, and it is composed of the main plate, sound-absorbing plate, and sound-absorbing material. Plastic noise barrier structures have several advantages compared to other products, such as light weight, anticorrosion, durability, easy assembly, rapid construction, and low costs. In this study, the main and sound-absorbing plates were manufactured through extrusion molding, and the sound-absorbing plate was finished with a press to improve the conventional injection molding. Extrusion molding dies and punch dies were designed, and a profile extrusion-molding system was developed. Thus, inexpensive and efficient sound-absorbing and main plates can be produced, and the noise barrier structure can be assembled rapidly. Additionally, a noise barrier structure with extended service life and excellent quality can be constructed by creating uniform free space to accommodate increased temperatures after assembly and installation.

• 대한후두음성언어의학회지
• /
• 제29권2호
• /
• pp.70-75
• /
• 2018

The office-based, un-sedated vocal fold injection laryngoplasty has re-emerged in the past decade as an appealing alternative to microsuspension laryngoscopic procedure which is conducted under general anesthesia. The trend toward vocal fold injection laryngoplasty in an in-office setting was possible due to technological evolution for visualization and new injection materials. However, invisibility of the injection needle has been the main shortcomings of cricothyroid approach. The purpose of this review is to provide an up-to-date review of office-based, trans-cricothyroid membrane approach injection laryngoplasty technique under local anesthesia and efforts made to increase the preciseness of amount and location of the injected materials in the management of glottic insufficiency. A review of variable efforts undertaken to maximize the result of cricothyroid approach by technically increasing accuracy of the location of needle tip was done. With the proper patient selection and utilization of the new technologies, office-based and un-sedated vocal fold injection laryngoplasty via cricothyroid approach can be redeem as a main-stay in the management of glottic insufficiency, such as vocal fold paralysis, vocal fold paresis, vocal fold atrophy and vocal fold scar.

• 한국분무공학회지
• /
• 제22권2호
• /
• pp.87-95
• /
• 2017

Recently, as the interest in environmental issues have increased around the world, the regulation on vehicle exhaust have been tightened in each country. To satisfy such tightened exhaust regulation, automotive manufactures are forced to equipped Diesel Particulate Filter (DPF) at Diesel vehicles. If DPF is used for a long time, DPF regeneration should be performed. The objective of this study is to research on post injection for DPF regeneration. The result of the study was that it was desired that retarding post injection timing, lower load of engine and smaller the amount of main fuel injection, for DPF regeneration. Oil dilution was tended to increase as load was lower, amount of post injection was increased, and post injection timing was retarded.

• 대한한방소아과학회지
• /
• 제23권1호
• /
• pp.205-228
• /
• 2009

Objectives The purpose of this study is to investigate the current acupuncture therapy of cerebral palsy. Methods We investigated the Chinese clinical papers which were published in the last 10 years(from 1999 to 2008). We found these papers from the oriental medical library in university and we also used the China National Knowledge Infrastructure(CNKI) through the internet and selected 32 papers for analyzing. Results Most papers were described the effect of acupuncture or acupoint-injection. This is more effective way to treat than the general rehabilitation treatment such as the physical therapy, the occupational therapy, and the speech therapy. Acupuncture or acupoint-injection has overall $80{\sim}100%$ of rehabilitation rate. The younger the children were, the longer the treatment period was, and the more successful in treatment. The acupuncture was often used with the general acupuncture and scalp acupuncture. Commonly used major acupuncture points were sishencong(四神聰), bohui(百會), zusanli(足三里), yundongqu(運動區), pinghengqu(平衡區), quchi(曲池), and sanyinjiao(三陰交). Commonly used main meridian pathways were bladder, governor vessel, gallbladder, large intestine, stomach, small intestine meridian. Head is the common site for acupuncture. The main acupoint-injection points were zusanli(足三里), dazhui(大椎), shenshu(腎兪), yamen(啞門), neiguan(內關), and fengchi(風池). For the injection, brain activator, ganglioside M1, cerebroprotein hydrolysate, cytidine diphosphate choline, Vit B1, Vit B12, the salviae root, the safflower were commonly used. Conclusions Acupuncture and acupoint-injection have been shown as an effective treatment on cerebral palsy. The acupuncture was used often the general acupuncture and scalp acupuncture all together. Commonly used main acupuncture points were sishencong, bohui, zusanli, yundongqu, pinghengqu, quchi, sanyinjiao.